全文获取类型
收费全文 | 10355篇 |
免费 | 10篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 38篇 |
废物处理 | 795篇 |
环保管理 | 1310篇 |
综合类 | 1091篇 |
基础理论 | 3252篇 |
污染及防治 | 1908篇 |
评价与监测 | 1052篇 |
社会与环境 | 918篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 12篇 |
2020年 | 3篇 |
2019年 | 9篇 |
2018年 | 1481篇 |
2017年 | 1385篇 |
2016年 | 1203篇 |
2015年 | 147篇 |
2014年 | 40篇 |
2013年 | 60篇 |
2012年 | 488篇 |
2011年 | 1376篇 |
2010年 | 716篇 |
2009年 | 627篇 |
2008年 | 910篇 |
2007年 | 1260篇 |
2006年 | 46篇 |
2005年 | 52篇 |
2004年 | 59篇 |
2003年 | 89篇 |
2002年 | 121篇 |
2001年 | 29篇 |
2000年 | 32篇 |
1999年 | 12篇 |
1998年 | 16篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 15篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1984年 | 20篇 |
1983年 | 15篇 |
1982年 | 7篇 |
1981年 | 3篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1974年 | 3篇 |
1961年 | 3篇 |
1957年 | 3篇 |
1952年 | 2篇 |
1949年 | 2篇 |
1935年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
A case of fatal generalized dystrophic epidermolysis bullosa is described in a prematurely born female whose mother had strikingly elevated mid-trimester serum and amniotic fluid alpha-fetoprotein concentrations, a positive amniotic fluid acetylcholinesterase band, and negative serial ultrasound studies. This case lends further support to an association between autosomal recessive generalized dystrophic epidermolysis bullosa and increased levels of alpha-fetoprotein, positive amniotic fluid acetylcholines'terase, and normal ultrasound findings. 相似文献
42.
Andreas Züttel 《Mitigation and Adaptation Strategies for Global Change》2007,12(3):343-365
Hydrogen storage and transportation or distribution is closely linked together. Hydrogen can be distributed continuously in
pipelines or batch wise by ships, trucks, railway or airplanes. All batch transportation requires a storage system but also
pipelines can be used as pressure storage system. Hydrogen exhibits the highest heating value per weight of all chemical fuels.
Furthermore, hydrogen is regenerative and environment friendly. There are two reasons why hydrogen is not the major fuel of
toady’s energy consumption: First of all, hydrogen is just an energy carrier. And, although it is the most abundant element
in the universe, it has to be produced, since on earth it only occurs in the form of water. This implies that we have to pay
for this energy, which results in a difficult economic task, because since the industrialization we are used to consuming
energy for free. The second difficulty with hydrogen as an energy carrier is the low critical temperature of 33 K, i.e. hydrogen
is a gas at room temperature. For mobile and in many cases also for stationary applications the volumetric and gravimetric
density of hydrogen in a storage system is crucial. Hydrogen can be stored by six different methods and phenomena: high pressure
gas cylinders (up to 800 bar), liquid hydrogen in cryogenic tanks (at 21 K), adsorbed hydrogen on materials with a large specific
surface area (at T < 100 K), absorbed on interstitial sites in a host metal (at ambient pressure and temperature), chemically bond in covalent
and ionic compounds (at ambient pressure), oxidation of reactive metals e.g. Li, Na, Mg, Al, Zn with water. These metals easily
react with water to the corresponding hydroxide and liberate the hydrogen from the water. Finally, the metal hydroxides can
be thermally reduced to the metals in a solar furnace. 相似文献
43.
FUENSANTA CARAVACA DINO FIGUEROA ANTONIO ROLDÁn CONCEPCIÓN AZCÓN-AGUILAR 《Environmental management》2003,31(3):0412-0420
The reestablisment of autochthonous plant species is an essential strategy for recovering degraded areas under semiarid conditions.
A field experiment was carried out to assess the short-term effect of two reafforestation methods involving mycorrhizal inoculation
and compost addition on soil quality parameters and Rhamnus lycioides seedling growth. The nutrient content (NPK) and enzymatic activities (dehydrogenase, urease, protease-BAA, acid phosphatase
and β-glucosidase) increased and bulk density decreased in the rhizosphere soil with the organic amendment. Biomass C of rhizosphere
soil increased by at least 240% with respect to the control soil after mycorrhizal inoculation and the combination of compost
addition + mycorrhizal inoculation. Both mycorrhizal inoculation and composted organic residue addition increased R. lycioides seedling growth in the same proportion. In the short term, we conclude that the application of both reafforestation methods
not only enhances the establishment of R. lycioides seedlings, but also improves soil quality. 相似文献
44.
The paper engages in the discussion of conducting research in war zones, initiated in Disasters by Barakat and Ellis. It looks specifically at possibilities for research in the war zones of Eritrea and Northern Ethiopia during the 1980s, and notes the ways in which this context differs from wars in the former Yugoslavia to which Barakat and Ellis mainly refer. The authors suggest that the unique context of every internal war, and the institutional actors that converge around this context, create both the potential and the demand for particular kinds of information, especially when humanitarian programmes involving international donors are under way. De-contexualising research in war zones from the specific context in which it occurs, in order to derive general guidelines, can thus be problematic. 相似文献
45.
Gunnar Horgen Arne Aar?s Marvin J Dainoff Maria Konarska Magne Thoresen Barbara G F Cohen 《International journal of occupational safety and ergonomics》2005,11(1):77-92
Three groups of data entry female visual display terminal (VDT) workers from Norway (n = 30), Poland (n = 33) and the USA (n = 29) were compared. Before intervention, the Norwegian group reported more neck pain compared with the Polish group. The Polish group reported less shoulder pain than both the U.S. and the Norwegian groups. The clinical examination documented fewer symptoms and signs of musculoskeletal illness among the Polish participants compared with the Norwegian and the U.S. groups. After intervention, the Norwegian group reported a reduction in neck pain while the U.S. group reported a reduction in shoulder pain. The Polish group reported an increase in neck, shoulder and forearm pain at follow-up compared to after intervention. The Polish group recorded higher flexion of the upper arm at follow-up parallel with an increase of pain in the upper part of the body. Visual discomfort showed variable results in the 3 countries. 相似文献
46.
Methane oxidation in slurry storage surface crusts 总被引:1,自引:0,他引:1
Livestock manure is a significant source of atmospheric methane (CH4), especially during liquid storage. In liquid manure (slurry) storages a surface crust may form naturally, or an artificial surface crust can be established. We investigated whether there is a potential for CH4 oxidation in this environment. Surface crust materials were sampled from experimental storages with cattle slurry (with natural crust) or anaerobically digested cattle slurry (with straw layer) that had been stored with or without a wooden cover. Extracts of surface crust material were incubated with 5.6% CH4 in the headspace, and methanotrophic activity was demonstrated in all four treatments following a 4- to 10-d lag phase. Subsequent incubation of field-moist surface crust material with 350 microL L(-1) CH4 also showed CH4 oxidation, indicating a potential for CH4 removal under practical storage conditions. There was no CH4 oxidation activity during incubation of autoclaved samples. Methane oxidation rates were 0.1 to 0.5 mg kg(-1) organic matter (OM) h(-1), which is comparable with the activity in wetlands and rice paddies. Partial drying increased CH4 oxidation to 0.2 to 1.4 mg kg(-1) OM h(-1), probably as a result of improved diffusivity within the surface crust. Rewetting reversed the stimulation of methanotrophic activity in some treatments, but not in others, possibly due to a decline in CH4 production in anaerobic volumes, or to growth of methanotrophs during incubation. This study presents direct evidence for methanotrophic activity in slurry storages. Measures to ensure crust formation with or without a solid cover appear to be a cost-effective greenhouse gas mitigation option. 相似文献
47.
48.
Biochar physicochemical parameters as a result of feedstock material and pyrolysis temperature: predictable for the fate of biochar in soil? 总被引:1,自引:0,他引:1
49.
Nguyen Kim Nga Huynh Dang Chinh Phi Thi Thuy Hong Tran Quang Huy 《Journal of Polymers and the Environment》2017,25(2):146-155
This study aimed at finding effective strategies for high-performance removal of reactive blue 19 (RB19) dye from aqueous solution. Chitosan (CS) films had been prepared by using solvent casting with mild drying for this purpose. The CS films were characterized by X-ray diffraction, field-emission scanning electron microscopy, and Fourier transform infrared (FTIR) spectroscopy. The performance of RB19 removal using CS were evaluated by varying contact time, solution pH, initial dye concentration, and adsorbent dosage. Adsorption isotherms, kinetics, and desorption were investigated by batch experiments. Results showed that CS films exhibited the optimal adsorption performance for RB19 removal and high maximum adsorption capacities of RB19, which were 799 and 822.4 mg g?1 at 20 and 40 °C, respectively. Adsorption kinetic data were well described by the pseudo-second-order kinetic model. FTIR analyses further indicated that interactions between RB19 and the CS film occurred during adsorption. The CS films also exhibited satisfactory desorption of RB19 at about 80 % after 30 min of desorption at pH 11. Our study demonstrated that the CS films can be easily prepared and applied for effective removal of RB19 in treatment of wastewater. 相似文献
50.
Doug P. Armstrong Elizabeth H. Parlato Barbara Egli Wendy J. Dimond Renske Kwikkel Åsa Berggren Mhairi McCready Kevin A. Parker John G. Ewen 《Conservation biology》2021,35(3):859-869
Inbreeding depression is an important long-term threat to reintroduced populations. However, the strength of inbreeding depression is difficult to estimate in wild populations because pedigree data are inevitably incomplete and because good data are needed on survival and reproduction. Predicting future population consequences is especially difficult because this also requires projecting future inbreeding levels and their impacts on long-term population dynamics, which are subject to many uncertainties. We illustrate how such projections can be derived through Bayesian state-space modeling methods based on a 26-year data set for North Island Robins (Petroica longipes) reintroduced to Tiritiri Matangi Island in 1992. We used pedigree data to model increases in the average inbreeding level (F ) over time based on kinship of possible breeding pairs and to estimate empirically Ne/N (effective/census population size). We used multiple imputation to model the unknown components of inbreeding coefficients, which allowed us to estimate effects of inbreeding on survival for all 1458 birds in the data set while modeling density dependence and environmental stochasticity. This modeling indicated that inbreeding reduced juvenile survival (1.83 lethal equivalents [SE 0.81]) and may have reduced subsequent adult survival (0.44 lethal equivalents [0.81]) but had no apparent effect on numbers of fledglings produced. Average inbreeding level increased to 0.10 (SE 0.001) as the population grew from 33 (0.3) to 160 (6) individuals over the 25 years, giving a ratio of 0.56 (0.01). Based on a model that also incorporated habitat regeneration, the population was projected to reach a maximum of 331–1144 birds (median 726) in 2130, then to begin a slow decline. Without inbreeding, the population would be expected stabilize at 887–1465 birds (median 1131). Such analysis, therefore, makes it possible to empirically derive the information needed for rational decisions about inbreeding management while accounting for multiple sources of uncertainty. 相似文献