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71.
Changes in functional structure of soil bacterial communities due to fungicide and insecticide applications in canola 总被引:1,自引:0,他引:1
Newton Z. Lupwayi K. Neil Harker Lloyd M. Dosdall T. Kelly Turkington Robert E. Blackshaw John T. ODonovan Hctor A. Crcamo Jennifer K. Otani George W. Clayton 《Agriculture, ecosystems & environment》2009,130(3-4):109-114
The fungicide vinclozolin and insecticide λ-cyhalothrin are widely used to control canola (Brassica spp.) diseases and insect pests, respectively, in Canada. We investigated non-target effects of these pesticides, applied at recommended rates, on soil microbial biomass, functional bacterial diversity and functional community structure of soil bacteria (by evaluating patterns of C substrate utilization) in canola rhizosphere and bulk soil at three locations in Alberta from 2002 to 2004. Experimental treatments were (a) untreated control, (b) vinclozolin fungicide foliar application, (c) λ-cyhalothrin insecticide foliar application, and (d) vinclozolin and λ-cyhalothrin applications. No significant pesticide effects on soil microbial biomass or functional bacterial diversity were observed, but the functional structures of soil bacteria were altered. In 1 of 12 cases, the control treatment had a different soil bacterial community structure from the 3 pesticide treatments. The fungicide treatment had different bacterial community structures from the control or insecticide treatments in 3 of 12 cases, the insecticide treatment had different community structures from the control or fungicide treatments in 4 of 12 cases, and the combined fungicide and insecticide treatment had different community structures from the other treatments in 3 of 12 cases. Therefore, evaluating soil bacterial functional structures revealed pesticide effects that were not detected when bacterial diversity or microbial biomass were measured in canola rhizosphere or bulk soil. 相似文献
72.
Vikas Yadav Patade Sujata Bhargava Penna Suprasanna 《Agriculture, ecosystems & environment》2009,134(1-2):24-28
Sugarcane, a glycophyte grown in the tropical and subtropical regions, is frequently subjected to soil salinity, affecting the yield and quality of the harvest. The ameliorative efficiency of salt priming on emergence and plantlet growth was examined in sugarcane cultivars which are known to vary in salt tolerance under field conditions. Salt priming with NaCl (100 mM) improved both the percent and rate of germination of the sets of the tolerant (Co 62175) and moderately tolerant (CoM 265) varieties compared to sensitive (CoC 671) and test variety (Co 86032). Salt priming during germination also improved the growth performance of two-month-old sugarcane plants in terms of shoot length, shoot and root fresh weight when subjected to 15 day iso-osmotic (−0.7 MPa) NaCl (150 mM) or polyethylene glycol (PEG 8000; 20%, w/v) stress. The primed plants exhibited lower salt- and dehydration-induced leaf senescence. The results suggest salt priming as an efficient approach for imparting abiotic stress tolerance in sugarcane. 相似文献
73.
Tradeoffs,synergies and traps among ecosystem services in the Lake Victoria basin of East Africa 总被引:1,自引:0,他引:1
Brent M. Swallow Joseph K. Sang Meshack Nyabenge Daniel K. Bundotich Anantha K. Duraiappah Thomas B. Yatich 《Environmental Science & Policy》2009,12(4):504-519
Lake Victoria is a crucial ecosystem for over 25 million people in Kenya, Uganda, Tanzania, Rwanda and Burundi who live in the basin, and for the greater Nile river system downstream of the lake. Ecosystem management in the Lake Victoria basin has been highly extractive for most of the last 60 years, with the 1990s a period of marked decline in food production, economic contraction, rising poverty, increased burden of human disease, and more frequent floods. Lake Victoria itself is becoming eutrophic, with related problems of species extinctions and invasive species. There is evidence of poverty–environment traps: some households and areas appear to be caught in vicious cycles of low income, low investment in soil management, declines in soil fertility, and soil loss, while other households and areas are able to achieve higher incomes and investments, maintain soil fertility, and conserve soil on their farms.Concepts and approaches from the Millenium Ecosystem Assessment (MA) were applied in a study of ecosystem service tradeoffs, synergies and traps in two of the river basins that flow into Lake Victoria from Kenya (Yala and Nyando). Hydrologic units are the main geographic unit used in the analysis, with predictions of sediment yield serving as the main measure of regulating services. Provisioning services are evaluated through a spatially disaggregated analysis of agricultural production, yield and area that combines spatial data from aerial photographs with division-level price and yield estimates.The results illustrate considerable year-to-year variation in land use, agricultural production and sediment yield in the two basins. While overall production appears to be relatively stable at the basin level, there have been shifts in the geographic locus of production toward the upper parts of both basins. A spatial overlay of production and sediment yield indicates that different parts of the basins exhibit tradeoffs, synergies and traps. Results from this study have multiple uses in rural planning, agricultural investment, and watershed management. The results also suggest that the poverty traps conceptual framework may help to enrich the interpretative content of the MA approach. 相似文献
74.
N. L. Panwar N. S. Rathore A. K. Kurchania 《Mitigation and Adaptation Strategies for Global Change》2009,14(6):547-556
This paper deals with field related experience of a low temperature industrial heat application through biomass gasification.
The gasification system is essentially consists of an open top down draft reactor lined with ceramic. The experiment reveals
that 6.5 kg of liquefy petroleum gas (LPG) is fully replaced by 38 kg of sized wood on hourly basis. The maximum temperature
attained was 367°C in 130 min at 100.7 Nm3 h−1 gas flow rate. This system has resulted a saving of about 19.5 tons of LPG over 3,000 h of operation, implying a saving of
about 33 tons of CO2 emission, thus a promising candidate for clean development mechanism. Fuel economic analysis of gasifier system showed that
the saving was about 13,850 US$ for 3,000 h of baking operation. 相似文献
75.
A.M. Fermont P.J.A. van Asten K.E. Giller 《Agriculture, ecosystems & environment》2008,128(4):239-250
Increasing land pressure during the past three to four decades has transformed farming systems in the mid-altitude zone of East Africa. Traditional millet-, cotton-, sugarcane- and/or banana-based farming systems with an important fallow and/or grazing component have evolved into continuously cultivated cassava or cassava/maize-based systems. Within three to four decades, cassava cultivation increased from 1–11 to 16–55% of cropped fields in our six study sites. Declining soil fertility, and not labour or food shortage, was apparently the primary trigger for this transformation. The land use changes have increased nutrient offtakes and reduced nutrient recycling rates. Cassava and maize now account for 50–90% of nutrient removal. Whereas single-season fallows were the most important source of nutrient recycling on cropped fields in the past, currently cassava litterfall and maize stover contribute roughly 70% of nutrient recycling, with 50–70% of N, P and K recycled in cassava litterfall. This may explain why many farmers reason that cassava ‘rests’ the soil. With increasing land use pressure farmers progressively use cassava as an ‘imitation fallow’ throughout their farm. Farmers increasingly target cassava to poor fertility fields characterized by low pH and available P. High cassava intensities are nonetheless maintained on more fertile fields, probably to guarantee regeneration of soil fertility on all fields. Once cassava is targeted to poor fertility soils, farmers have run out of low-input management options and need to intensify management to maintain system productivity. As cassava is now used by more farmers and on a larger acreage than fallowing in the studied farming systems, cassava cropping could perhaps serve as an excellent entry point to strengthen system sustainability. 相似文献
76.
Runoff and sediment losses from 27 upland catchments in Southeast Asia: Impact of rapid land use changes and conservation practices 总被引:5,自引:0,他引:5
C. Valentin F. Agus R. Alamban A. Boosaner J.P. Bricquet V. Chaplot T. de Guzman A. de Rouw J.L. Janeau D. Orange K. Phachomphonh Do Duy Phai P. Podwojewski O. Ribolzi N. Silvera K. Subagyono J.P. Thibaux Tran Duc Toan T. Vadari 《Agriculture, ecosystems & environment》2008,128(4):225-238
Rapid changes in upland farming systems in Southeast Asia generated predominantly by increased population pressure and ‘market forces’ have resulted in widespread land degradation that has been well documented at the plot scale. Yet, the links between agricultural activities in the uplands and downstream off-site effects remain largely unknown because of the difficulties in transferring results from plots to a larger scale. Many authors have thus pointed out the need for long-term catchment studies. The objective of this paper is to summarize the results obtained by the Management of Soil Erosion Consortium (MSEC) over the last 5 years from 27 catchments in five countries (Indonesia, Laos, Philippines, Thailand, and Vietnam). The purpose of the study was to assess the impacts of cultivation practices on annual runoff and erosion rates. Initial surveys in each catchment included topography, soils and land use. Monitoring included climatic, hydrologic and erosion (total sediment yield including bed load and suspended sediment load) data, land use and crop yields, and farmers’ income. In addition, new land management options were introduced through consultations with farmers and evaluated in terms of runoff and erosion. These included tree plantations, fruit trees, improved fallow with legumes, maize intercropped with legumes, planted fodder, native grass strips and agro-ecological practices (direct sowing and mulch-based conservation agriculture). Regressions analyses showed that runoff during the rainy season, and normalized runoff flow coefficient based on erosive rainfall during the rainy season (rainfall with intensity exceeding 25 mm h−1) increase with the percentage of the catchment covered by maize. Both variables decrease with increasing soil depth, standard deviation of catchment slope (that reflects terrain roughness), and the percentages of the catchment covered by fallow (regular and improved), tree plantations and planted fodder. The best predictors of sediment yield were the surface percentages of maize, Job's tears, cassava and footpaths. The main conclusions generated from this study were: (i) soil erosion is predominantly influenced by land use rather than environmental characteristics not only at the plot scale but also at the catchment scale; (ii) slash-and-burn shifting cultivation with sufficiently long rotations (1 year of cultivation, 8 years of fallow) is too often unjustly blamed for degradation; (iii) in its place, continuous cropping of maize and cassava promotes high rates of soil erosion at the catchment scale; (iv) conservation technologies are efficient in reducing runoff and total sediment yield at the catchment scale; (v) the adoption of improved soil management technologies by upland farmers is not a function of the degree of intensification of their farming system and/or of their incomes. The results suggest that if expansion of maize and cassava into already degraded upland systems were to occur due to increased demand for biofuels, there is a risk of higher runoff and sediment generation. A failure to adopt appropriate land use management strategies will result in further rapid resource degradation with negative impacts to downstream communities. 相似文献
77.
A bacterium classified as Achromobacter xylosoxidans strain IR08 by phenotypic typing coupled with 16S rRNA gene analysis was isolated from a soil contaminated with electrical transformer ?uid for over sixty years using Aroclor 1221 as an enrichment substrate. The substrate utilization profiles revealed that IR08 could grow on all three monochlorobiphenyls (CBs), 2,4'- and 4,4'-dichlorobiphenyl as well as 2-chlorobenzoate (2-CBA), 3-CBA, 4-CBA, and 2,3-dichlorobenzoate. Unusually, growth was poorly sustaine... 相似文献
78.
Shamama Afreen Nitasha Sharma Rajiv K. Chaturvedi Ranjith Gopalakrishnan N. H. Ravindranath 《Mitigation and Adaptation Strategies for Global Change》2011,16(2):177-197
Due to large scale afforestation programs and forest conservation legislations, India’s total forest area seems to have stabilized
or even increased. In spite of such efforts, forest fragmentation and degradation continues, with forests being subject to
increased pressure due to anthropogenic factors. Such fragmentation and degradation is leading to the forest cover to change
from very dense to moderately dense and open forest and 253 km2 of very dense forest has been converted to moderately dense forest, open forest, scrub and non-forest (during 2005–2007).
Similarly, there has been a degradation of 4,120 km2 of moderately dense forest to open forest, scrub and non-forest resulting in a net loss of 936 km2 of moderately dense forest. Additionally, 4,335 km2 of open forest have degraded to scrub and non-forest. Coupled with pressure due to anthropogenic factors, climate change
is likely to be an added stress on forests. Forest sector programs and policies are major factors that determine the status
of forests and potentially resilience to projected impacts of climate change. An attempt is made to review the forest policies
and programs and their implications for the status of forests and for vulnerability of forests to projected climate change.
The study concludes that forest conservation and development policies and programs need to be oriented to incorporate climate
change impacts, vulnerability and adaptation. 相似文献
79.
N. H. Ravindranath Rajiv K. Chaturvedi N. V. Joshi R. Sukumar Jayant Sathaye 《Mitigation and Adaptation Strategies for Global Change》2011,16(2):211-227
Climate change is projected to impact forest ecosystems, including biodiversity and Net Primary Productivity (NPP). National
level carbon forest sector mitigation potential estimates are available for India; however impacts of projected climate change
are not included in the mitigation potential estimates. Change in NPP (in gC/m2/yr) is taken to represent the impacts of climate change. Long term impacts of climate change (2085) on the NPP of Indian
forests are available; however no such regional estimates are available for short and medium terms. The present study based
on GCM climatology scenarios projects the short, medium and long term impacts of climate change on forest ecosystems especially
on NPP using BIOME4 vegetation model. We estimate that under A2 scenario by the year 2030 the NPP changes by (−5) to 40% across
different agro-ecological zones (AEZ). By 2050 it increases by 15% to 59% and by 2070 it increases by 34 to 84%. However,
under B2 scenario it increases only by 3 to 25%, 3.5 to 34% and (−2.5) to 38% respectively, in the same time periods. The
cumulative mitigation potential is estimated to increase by up to 21% (by nearly 1 GtC) under A2 scenario between the years
2008 and 2108, whereas, under B2 the mitigation potential increases only by 14% (646 MtC). However, cumulative mitigation
potential estimates obtained from IBIS—a dynamic global vegetation model suggest much smaller gains, where mitigation potential
increases by only 6% and 5% during the period 2008 to 2108. 相似文献
80.
Amireeta K. Rawlani Benjamin K. Sovacool 《Mitigation and Adaptation Strategies for Global Change》2011,16(8):845-863
This article explores the drivers, benefits, and challenges to climate change adaptation in Bangladesh. It specifically investigates
the “Community Based Adaptation to Climate Change through Coastal Afforestation Program,” a 5-year $5 million adaptation scheme
being funded and implemented in part by the Government of Bangladesh, United Nations Development Program, and Global Environment
Facility. The article explores how the CBACC-CA builds various types of adaptive capacity in Bangladesh and the extent its
design and implementation offers lessons for other adaptation programs around the world. The first part of the study begins
by describing its research methods consisting of research interviews, site visits, and a literature review. It then summarizes
six primary sectors vulnerable to climate change in Bangladesh: water resources and coastal zones, infrastructure and human
settlements, agriculture and food security, forestry and biodiversity, fisheries, and human health. The article next describes
the genesis and background behind the CBACC-CA, with an emphasis on components that promote capacity development, demonstration
projects, risk reduction, and knowledge management. The article concludes that technology by itself is only a partial component
of successful adaptation efforts, and that multiple and integrated adaptation measures that cut across sectors and social,
institutional, and infrastructural dimensions are needed to truly build resilience and effectiveness. 相似文献