全文获取类型
收费全文 | 45223篇 |
免费 | 387篇 |
国内免费 | 318篇 |
专业分类
安全科学 | 1394篇 |
废物处理 | 2081篇 |
环保管理 | 6134篇 |
综合类 | 7248篇 |
基础理论 | 12124篇 |
环境理论 | 19篇 |
污染及防治 | 11063篇 |
评价与监测 | 2983篇 |
社会与环境 | 2593篇 |
灾害及防治 | 289篇 |
出版年
2022年 | 358篇 |
2021年 | 458篇 |
2020年 | 335篇 |
2019年 | 410篇 |
2018年 | 599篇 |
2017年 | 669篇 |
2016年 | 1021篇 |
2015年 | 730篇 |
2014年 | 1158篇 |
2013年 | 3613篇 |
2012年 | 1400篇 |
2011年 | 1909篇 |
2010年 | 1560篇 |
2009年 | 1616篇 |
2008年 | 1963篇 |
2007年 | 1940篇 |
2006年 | 1732篇 |
2005年 | 1537篇 |
2004年 | 1478篇 |
2003年 | 1420篇 |
2002年 | 1348篇 |
2001年 | 1623篇 |
2000年 | 1162篇 |
1999年 | 693篇 |
1998年 | 554篇 |
1997年 | 588篇 |
1996年 | 606篇 |
1995年 | 711篇 |
1994年 | 620篇 |
1993年 | 559篇 |
1992年 | 564篇 |
1991年 | 553篇 |
1990年 | 547篇 |
1989年 | 524篇 |
1988年 | 484篇 |
1987年 | 428篇 |
1986年 | 398篇 |
1985年 | 401篇 |
1984年 | 462篇 |
1983年 | 416篇 |
1982年 | 475篇 |
1981年 | 401篇 |
1980年 | 314篇 |
1979年 | 348篇 |
1978年 | 310篇 |
1977年 | 269篇 |
1975年 | 252篇 |
1974年 | 254篇 |
1973年 | 292篇 |
1972年 | 266篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
Extension of EU Emissions Trading Scheme to Other Sectors and Gases: Consequences for Uncertainty of Total Tradable Amount 总被引:1,自引:0,他引:1
Emissions trading in the European Union (EU), covering the least uncertain emission sources of greenhouse gas emission inventories
(CO2 from combustion and selected industrial processes in large installations), began in 2005. During the first commitment period
of the Kyoto Protocol (2008–2012), the emissions trading between Parties to the Protocol will cover all greenhouse gases (CO2, CH4, N2O, HFCs, PFCs, and SF6) and sectors (energy, industry, agriculture, waste, and selected land-use activities) included in the Protocol. In this paper,
we estimate the uncertainties in different emissions trading schemes based on uncertainties in corresponding inventories.
According to the results, uncertainty in emissions from the EU15 and the EU25 included in the first phase of the EU emissions
trading scheme (2005–2007) is ±3% (at 95% confidence interval relative to the mean value). If the trading were extended to
CH4 and N2O, in addition to CO2, but no new emissions sectors were included, the tradable amount of emissions would increase by only 2% and the uncertainty
in the emissions would range from −4 to +8%. Finally, uncertainty in emissions included in emissions trading under the Kyoto
Protocol was estimated to vary from −6 to +21%. Inclusion of removals from forest-related activities under the Kyoto Protocol
did not notably affect uncertainty, as the volume of these removals is estimated to be small. 相似文献
172.
Martyn N. Futter Lars Högbom Salar Valinia Ryan A. Sponseller Hjalmar Laudon 《Ambio》2016,45(2):188-202
We present a framework for evaluating and communicating effects of human activity on water quality in managed forests. The framework is based on the following processes: atmospheric deposition, weathering, accumulation, recirculation and flux. Impairments to water quality are characterized in terms of their extent, longevity and frequency. Impacts are communicated using a “traffic lights” metaphor for characterizing severity of water quality impairments arising from forestry and other anthropogenic pressures. The most serious impairments to water quality in managed boreal forests include (i) forestry activities causing excessive sediment mobilization and extirpation of aquatic species and (ii) other anthropogenic pressures caused by long-range transport of mercury and acidifying pollutants. The framework and tool presented here can help evaluate, summarize and communicate the most important issues in circumstances where land management and other anthropogenic pressures combine to impair water quality and may also assist in implementing the “polluter pays” principle. 相似文献
173.
The flow of carbon from plant roots into soil supports a range of microbial processes and is therefore critical to ecosystem function and health. Pollution-induced stress, which influences rhizosphere C flow is of considerable potential importance, and therefore needs to be evaluated. This paper reports on a method, based on reporter gene technology, for quantifying pollutant effects on rhizosphere C flow. The method uses the lux-marked rhizobacterium Pseudomonas fluorescens, where bioluminescence output of this biosensor is directly correlated with the metabolic activity and reports on C flow in root exudate. Plantago lanceolata was treated with paraquat (representing a model pollutant stress) in a simple microcosm system. The lux-biosensor response correlated closely with C concentrations in the exudate and demonstrated that the pollutant stress increased the C flow from the plantago roots, 24 h after application of the herbicide. The lux-reporter system therefore potentially offers a technique for use in assessing the impact of pollutant stress on rhizosphere C flow through the soil microbial biomass. 相似文献
174.
A solid-phase microbiological assay was used to determine the changes in genotoxicity associated with sequestration or biodegradation of carcinogenic compounds in contaminated soils. The concentration of six carcinogenic polycyclic aromatic hydrocarbons (PAHs) did not change in 59 d in sterile soil, but the genotoxicity declined markedly. In a soil undergoing bioremediation in the field for 147 d or biodegradation in the laboratory for 180 d, the concentrations either changed little or declined at different rates, but the genotoxicity increased followed by a decline. The genotoxicity of a second soil declined as a result of biological treatment. The data show that genotoxicity of contaminated soils may be unrelated to the concentration of carcinogenic PAHs because of aging or new mutagens formed during biological treatment. 相似文献
175.
Forsberg A Söderlund S Frank A Petersson LR Pedersén M 《Environmental pollution (Barking, Essex : 1987)》1988,49(4):245-263
Concentrations of eleven metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn) were determined in the brown seaweed Fucus vesiculosus collected from the Archipelago of Stockholm. Several factors which influence the metal content in the seaweed have been studied, including errors caused by epiphytes, sea exposure and differences depending on which part of the seaweed is analysed. It is concluded that, if all these factors are considered, Fucus vesiculosus plants are excellent bio-indicators of metal pollution. This is also demonstrated by a significant increase in metal content in transplanted Fucus vesiculosus near the city of Stockholm. The results from this investigation also indicate increasing metal concentrations, especially Cd, in samples from the northern parts of the Archipelago and the reason for this is discussed. 相似文献
176.
Suneel V. Sathish Kumar S. Balaji R. Vethamony P. 《Environmental science and pollution research international》2021,28(14):17181-17199
Environmental Science and Pollution Research - Formation of oil-suspended sediment aggregates (OSAs) is believed to be one of the natural cleaning processes in the marine environment. In this... 相似文献
177.
178.
I. N. Sukhanova M. V. Flint G. Hibaum V. Karamfilov A. I. Kopylov E. Matveeva T. N. Rat'kova A. F. Sazhin 《Marine Biology》1988,99(1):1-8
The structure and some functional characteristics of the plankton community at the time of aExuviaella cordata red tide were investigated in Burgas Bay, Bulgaria, in May and June 1986. Characteristics of main plankton components (phyto-, bacterio-, nanoheterotrophic plankton, ciliates and mesoplankton) in the bloom area are presented. Development of theE. cordata bloom was determined by abiotic conditions among which eutrophication and salinity decrease caused the patchy character of its rapid development. Attainment of maximum red tide (ca. 1x109 cells l-1; 1x103 g m-3) from background (500 to 800x103 cells l-1; 600 mg m-3) took 3 to 7d. Growth rate () during that period was 1.2 to 2.2 doublings per day. A sharp bloom decline (3 to 4d) was caused by parasitic flagellates destroying the alga's chloroplast. Diel biomass losses due to grazing remained below 5%. Metabolites and degradation products ofE. cordata revealed no pronounced toxic effects on the other components of the planktonic community. The rapid bloom degradation due to the effects of parasitic flagellates indicates the high potential of ecosystem self-regulation. 相似文献
179.
Jos L. Mateos Paloma Fern ndez Del Pino Francisco J. Guti rrez Ma ero Marí a Ruiz Palomino Juan J. Colon Jos A. Lucas Garcí a Agustí n Probanza 《Chemistry and Ecology》2000,17(2):125-152
Microbial communities (phospholipid fatty acid pattern, bacterial growing strategies, eco-physiological index (EPI) and total bacteria counts, as a number of heterotrophic cuhurable bacteria), substrate-induced respiration (SIR), and nitrogen mineralization were studied in three Mediterranean soils at three different depth levels (A, B and C). Soils were experimentally treated with a final concentration of 1000 ppm of trace metals (Cu2+, Zn2+, Al3+, Fe2+, Pb2+, Ni2+, Mn2+, Cr3+ and Cd2+). Soils were stored in 571 plastic containers for one year, and watered with 1001 during this period. Leachate was recovered through a bottom tap. Samples of the three depths were studied. Soil microbial communities showed different effects to other studies presented in the literature, but carried out on non-Mediterranean soils. Dramatic differences were found between treated soils and untreated ones, but not between soils or horizons. the treated soil displayed a decrease in CFUs, SIR N-mineralization and EPI together with a dominance of r-growing strategists. the relative moles percent of several PLFAs, especially 15:0, 16: 1ω7, cy17: 0, br18:0 and 18: 1ω7 decreased because of the pollution of soils, whereas 10Me16, 18:2ω6, cy19:0, i16:0 and br17:0 showed higher values than in untreated soils. 相似文献
180.
T. R. Pope 《Behavioral ecology and sociobiology》2000,48(4):253-267
Evaluation of evolutionary mechanisms proposed to promote cooperative behavior depends on the relative influence of the behavior
on the reproductive success of individuals, the reproductive success of the group in which they interact behaviorally, and
the degree of gene correlation among cooperators. The genetic relationship within cooperative coalitions of female red howler
monkeys was examined for three populations with different densities and growth rates. Patterns of gene correlation change
within coalitions is documented using data from the mitochondrial and nuclear genomes, and long-term census monitoring. Differences
in fecundity and infant survivorship within and between groups of unrelated (rˉ=0) and related (rˉ≥ 0.25) females are compared. Females that emigrate from their natal groups form coalitions with other migrant females. These
coalitions attempt to establish a territory and, once successful in producing offspring, exclude other females from feeding
resources. Females in these coalitions had different mtDNA haplotypes and a genetically estimated mean r of 0, supporting demographic data on emigration patterns indicating that these females rarely have the opportunity to form
coalitions with kin. Patterns of recruitment and rate of matriline development within social groups supported behavioral data
indicating that females actively attempt to promote their own matriline as breeders over that of other females, and that some
matrilines are more successful at this than others. Mean r among females was significantly higher in coalitions established as social groups for several generations (rˉ=0.44). In these groups, females all shared the same mtDNA haplotype, and mtDNA haplotype divergence was significantly higher
between than within groups. Females in coalitions with kin had significantly higher reproductive success than females in unrelated
coalitions in all populations. This difference was not a function of coalition size, number of males, socionomic sex ratio,
or primiparity, although anecdotal evidence suggests that allomothering may compensate for inept new mothers in related coalitions
more often than in unrelated ones. Differences in territory quality could not be ruled out as a potential causal factor in
the saturated populations, but were unlikely in the low-density, growing population. There were substantial differences among
long-established coalitions in overall reproductive output in all three populations, and this was significantly correlated
with the number of breeding females. Increase in coalition size was a function of both group age and the behavioral tolerance
among females. Regardless of the underlying reasons for the patterns observed, reproductive success clearly increases with
degree of gene correlation among females within cooperative coalitions, and coalitions that recruit more daughters produce
more offspring. The nature of the cooperative relationship among group females directly influences both of these outcomes.
This is associated with substantial genetic differentiation among social groups within populations, creating conditions in
which genetic tendencies towards cooperative behavior can become tightly associated with group reproductive success.
Received: 15 September 1999 / Revised: 27 April 2000 / Accepted: 27 May 2000 相似文献