全文获取类型
收费全文 | 4064篇 |
免费 | 18篇 |
国内免费 | 51篇 |
专业分类
安全科学 | 77篇 |
废物处理 | 137篇 |
环保管理 | 456篇 |
综合类 | 1002篇 |
基础理论 | 893篇 |
环境理论 | 3篇 |
污染及防治 | 910篇 |
评价与监测 | 287篇 |
社会与环境 | 359篇 |
灾害及防治 | 9篇 |
出版年
2022年 | 36篇 |
2021年 | 66篇 |
2020年 | 31篇 |
2019年 | 36篇 |
2018年 | 63篇 |
2017年 | 57篇 |
2016年 | 90篇 |
2015年 | 55篇 |
2014年 | 118篇 |
2013年 | 319篇 |
2012年 | 120篇 |
2011年 | 180篇 |
2010年 | 123篇 |
2009年 | 163篇 |
2008年 | 155篇 |
2007年 | 176篇 |
2006年 | 141篇 |
2005年 | 118篇 |
2004年 | 111篇 |
2003年 | 130篇 |
2002年 | 122篇 |
2001年 | 134篇 |
2000年 | 95篇 |
1999年 | 63篇 |
1998年 | 33篇 |
1997年 | 41篇 |
1996年 | 25篇 |
1995年 | 55篇 |
1994年 | 33篇 |
1993年 | 37篇 |
1992年 | 38篇 |
1991年 | 37篇 |
1990年 | 49篇 |
1989年 | 40篇 |
1988年 | 28篇 |
1987年 | 31篇 |
1986年 | 23篇 |
1985年 | 31篇 |
1984年 | 26篇 |
1983年 | 38篇 |
1982年 | 26篇 |
1981年 | 41篇 |
1980年 | 30篇 |
1979年 | 30篇 |
1977年 | 25篇 |
1976年 | 28篇 |
1975年 | 25篇 |
1972年 | 23篇 |
1970年 | 23篇 |
1965年 | 23篇 |
排序方式: 共有4133条查询结果,搜索用时 15 毫秒
211.
212.
Species composition of fishes was studied in rivers (capture sites) inhabited by the riffle minnow. In some localities, this species proved to occupy a leading position in the ichthyofauna, being obviously dominant. In small rivers, 16 species were caught together with it, including seven species regularly occurring in catches. The relative abundance of riffle minnow showed a moderate positive correlation with that of the gudgeon (0.568) and a nonsignificant negative correlation (?0.399) with that of the bleak. It is probable that the population dynamics of riffle minnow are determined mainly by natural intraspecific mechanisms rather than by water quality, which has changed only slightly in the rivers studied. 相似文献
213.
The objectives of this study were to quantitatively estimate the distribution of arsenic with its speciation and to identify potential pathways for transformation of arsenic species from samples of water, sediments, and plants in the ecosystem affected by the Cheongog Spring, where As(V) concentration reached levels up to 0.270 mg L−1. After flowing about 100 m downstream, the arsenic level showed a marked reduction to 0.044 mg L−1 (about 84% removal) without noticeable changes in major water chemistry. The field study and laboratory hydroponic experiments with the dominant emergent plants along the creek (water dropwort and thunbergian smartweed) indicated that arsenic distribution, reduction, and speciation appear to be controlled by, (i) sorption onto stream sediments in exchangeable fractions, (ii) bioaccumulation by and possible release from emergent plants, and (iii) transformation of As(V) to As(III) and organic species through biological activities. 相似文献
214.
A.O. Babatunde Y.Q. Zhao M.A. Morris 《Environmental pollution (Barking, Essex : 1987)》2009,157(10):2830-2836
Aluminium-based water treatment residual (Al-WTR) is the most widely generated residual from water treatment facilities worldwide. It is regarded as a by-product of no reuse potential and landfilled. This study assessed Al-WTR as potential phosphate-removing substrate in engineered wetlands. Results indicate specific surface area ranged from 28.0 m2 g−1 to 41.4 m2 g−1. X-ray Diffraction, Fourier transform infrared and energy-dispersive X-ray spectroscopes all indicate Al-WTR is mainly composed of amorphous aluminium which influences its phosphorus (P) adsorption capacity. The pH and electrical conductivity ranged from 5.9 to 6.0 and 0.104 dS m−1 to 0.140 dS m−1 respectively, showing that it should support plant growth. Batch tests showed adsorption maxima of 31.9 mg P g−1 and significant P removal was achieved in column tests. Overall, results showed that Al-WTR can be used for P removal in engineered wetlands and it carries the benefits of reuse of a by-product that promotes sustainability. 相似文献
215.
T.J. Wallington M.D. Hurley O.J. Nielsen 《Atmospheric environment (Oxford, England : 1994)》2009,43(27):4247-4249
The infrared spectrum of HCF2OCF2OCF2CF2OCF2H (CAS# 188690-77-9) has been re-measured. The integrated absorption intensity over the range 1000–1500 cm?1 measured in the present work is (6.65 ± 0.33) × 10?17 cm2 molecule?1 cm?1 in 700 Torr of air at 296 K. The radiative efficiency of HCF2OCF2OCF2CF2OCF2H is calculated to be 1.02 W m?2 ppb?1. The value reported in the 2007 Intergovernmental Panel on Climate Change (IPCC) report is approximately 35% larger reflecting what we believe to be an erroneously high value for the absorption strength of HCF2OCF2OCF2CF2OCF2H adopted by the IPCC. 相似文献
216.
Shadi Dayyani Chandra A. Madramootoo Peter Enright Guillaume Simard Apurva Gullamudi Shiv O. Prasher Ali Madani 《Journal of the American Water Resources Association》2009,45(3):779-792
Abstract: The hydrologic performance of DRAINMOD 5.1 was assessed for the southern Quebec region considering freezing/thawing conditions. A tile drained agricultural field in the Pike River watershed was instrumented to measure tile drainage volumes. The model was calibrated using water table depth and subsurface flow data over a two‐year period, while another two‐year dataset served to validate the model. DRAINMOD 5.1 accurately simulated the timing and magnitude of subsurface drainage events. The model also simulated the pattern of water table fluctuations with a good degree of accuracy. The R2 between the observed and simulated daily WTD for calibration was >0.78, and that for validation was 0.93. The corresponding coefficients of efficiency (E) were >0.74 and 0.31. The R2 and E values for calibration/validation of subsurface flow were 0.73/0.48 and 0.72/0.40, respectively. DRAINMOD simulated monthly subsurface flow quite accurately (E > 0.82 and R2 > 0.84). The model precisely simulated daily/monthly drain flow over the entire year, including the winter months. Thus DRAINMOD 5.1 performed well in simulating the hydrology of a cold region. 相似文献
217.
Polybrominated diphenyl ethers (PBDEs) in leachates from selected landfill sites in South Africa 总被引:2,自引:0,他引:2
The last few decades have seen dramatic growth in the scale of production and the use of polybrominated diphenyl ethers (PBDEs) as flame retardants. Consequently, PBDEs such as BDE -28, -47, -66, -71, -75, -77, -85, -99, -100, -119, -138, -153, -154, and -183 have been detected in various environmental matrices. Generally, in South Africa, once the products containing these chemicals have outlived their usefulness, they are discarded into landfill sites. Consequently, the levels of PBDEs in leachates from landfill sites may give an indication of the general exposure and use of these compounds. The present study was aimed at determining the occurrence and concentrations of most common PBDEs in leachates from selected landfill sites. The extraction capacities of the solvents were also tested. Spiked landfill leachate samples were used for the recovery tests. Separation and determination of the PBDE congeners were carried out with a gas chromatograph equipped with Ni63 electron capture detector. The mean percentage recoveries ranged from 63% to 108% (n=3) for landfill leachate samples with petroleum ether giving the highest percentage extraction. The mean concentrations of PBDEs obtained ranged from ND to 2670pgl(-1), ND to 6638pgl(-1), ND to 7230pgl(-1), 41 to 4009pgl(-1), 90 to 9793pgl(-1) for the Garankuwa, Hatherly, Kwaggarsrand, Soshanguve and Temba landfill sites, respectively. Also BDE -28, -47, -71 and BDE-77 were detected in the leachate samples from all the landfill sites; and all the congeners were detected in two of the oldest landfill sites. The peak concentrations were recorded for BDE-47 at three sites and BDE-71 and BDE-75 at two sites. The highest concentration, 9793+/-1.5pgl(-1), was obtained for the Temba landfill site with the highest BOD value. This may suggest some influence of organics on the level of PBDEs. Considering the leaching characteristics of brominated flame retardants, there is a high possibility that with time these compounds may infiltrate into the groundwater around the sites since most of the sites are not adequately lined. 相似文献
218.
This paper presents and tests an integrative model of voluntary learning behavior. Drawing on social exchange theory, we argue that individuals are more likely to pursue learning activities when they identify with their employing organization and have a high quality leader–member exchange (LMX) relationship with their supervisor. We further argue that organizational identification is enhanced by both distributive and procedural fairness, whereas LMX quality is enhanced by interpersonal and informational fairness. Moreover, we contend that effective learning behavior improves job performance. The model was tested with a sample of 398 employees from a large automobile dealership. Results supported most predictions. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
219.
Two strains of Pseudomonas species (B2 and D5)selected from an array of lead solubilizing and accumulatingbacteria obtained from the effluent contaminated soil samples of abattery manufacturing factory were studied. Increase in pH between 4.0 and 6.0 favoured the growth of isolates: Peaklog10 cfu mL–1 values of 7.1, 7.5 and 8.5 wereobtained at pH 4, 5 and 6, respectively.Cell bound lead concentrations for B2 (0.34 mg mL–1)and D5 (0.30 mg mL–1) obtained by direct contact withPbs were greater than lead concentrations of 0.89 and 0.25 mg mL–1 for B2 and D5, respectively,obtained in dialyzed cultures. These cell bound lead concentration in undialyzed cultures were alsogreater than lead concentrations of 0.03 and 0.07 mg mL–1 for B2 and D5 in culture supernatants. Glucose addition did nor improve lead accumulation in the isolates.Exploitation of such isolates for the biotreatment of lead ladeneffluent was conducted. 相似文献
220.
Rai UN Dubey S Shukla OP Dwivedi S Tripathi RD 《Environmental monitoring and assessment》2008,144(1-3):469-481
The water bodies of Lucknow, Unnao and Kanpur (U.P.), India polluted through various point and non point sources were found to be either eutrophic or oligotrophic in nature. These water bodies supported a great number of algal diversity, which varied seasonally depending upon the physico-chemical properties of water. Further, the water bodies polluted through non point sources supports diverse algal species, while the water bodies polluted through point sources supports growth of tolerant blue green algae. High biomass producing algal species growing in these water bodies have accumulated significant amount of metals in their tissues. Maximum amount of Fe was found accumulated by species of Oedogonium sp. II (20,523.00 mug g(-1) dw) and Spirogyra sp. I (4,520.00 mug g(-1) dw), while maximum Chromium (Cr) was found accumulated in Phormedium bohneri (2,109.00 mug g(-1) dw) followed by Oscillatoria nigra (1,957.88 mug g(-1) dw) and Oedogonium sp. I (156.00 mug g(-1) dw) and Ni in Ulothrix sp. (495.00 mug g(-1) dw). Results showed that some of these forms growing in polluted environment and accumulating high amounts of toxic metals may be used as bioindicator species, however, their performance in metal contaminated water under different ecological niche is to be ascertained. 相似文献