全文获取类型
收费全文 | 3305篇 |
免费 | 32篇 |
国内免费 | 171篇 |
专业分类
安全科学 | 97篇 |
废物处理 | 195篇 |
环保管理 | 289篇 |
综合类 | 587篇 |
基础理论 | 776篇 |
环境理论 | 2篇 |
污染及防治 | 1127篇 |
评价与监测 | 239篇 |
社会与环境 | 183篇 |
灾害及防治 | 13篇 |
出版年
2023年 | 17篇 |
2022年 | 69篇 |
2021年 | 39篇 |
2020年 | 25篇 |
2019年 | 37篇 |
2018年 | 116篇 |
2017年 | 50篇 |
2016年 | 76篇 |
2015年 | 84篇 |
2014年 | 89篇 |
2013年 | 265篇 |
2012年 | 88篇 |
2011年 | 157篇 |
2010年 | 138篇 |
2009年 | 150篇 |
2008年 | 161篇 |
2007年 | 186篇 |
2006年 | 140篇 |
2005年 | 117篇 |
2004年 | 143篇 |
2003年 | 138篇 |
2002年 | 114篇 |
2001年 | 239篇 |
2000年 | 143篇 |
1999年 | 71篇 |
1998年 | 40篇 |
1997年 | 47篇 |
1996年 | 33篇 |
1995年 | 40篇 |
1994年 | 42篇 |
1993年 | 41篇 |
1992年 | 30篇 |
1991年 | 35篇 |
1990年 | 27篇 |
1989年 | 32篇 |
1988年 | 20篇 |
1987年 | 17篇 |
1986年 | 18篇 |
1985年 | 15篇 |
1984年 | 18篇 |
1983年 | 22篇 |
1982年 | 22篇 |
1981年 | 16篇 |
1980年 | 11篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 8篇 |
1975年 | 12篇 |
1973年 | 9篇 |
1972年 | 10篇 |
排序方式: 共有3508条查询结果,搜索用时 15 毫秒
951.
Chlorophenols were adsorbed from gas phase on allophane, Na- and Fe(III)-ion exchanged montmorillonites at room temperature and the reaction on clay surfaces was followed by GC-MS analysis of extracts of the adsorbates. Besides chlorinated biphenyldiols and hydroxydiphenyl ethers, chlorinated hydroxydibenzofurans were formed on Fe(III)-montmorillonite. 相似文献
952.
Chen KS Ho YT Lai CH Tsai YA Chen SJ 《Journal of the Air & Waste Management Association (1995)》2004,54(1):36-48
This work analyzes the variations in daily maximum 1-hr ozone (O3) concentrations and the long-term trends in annual means of hourly ambient concentrations of O3, nitrogen oxides (nitrous oxide + nitrogen dioxide), and nonmethane hydrocarbons in the three administrative regions of Kao-Ping airshed in southern Taiwan over a recent 8-yr period. The annual or monthly means of all maxima, most 95th percentiles, and some 90th percentiles of the daily maximum 1-hr O3 concentrations exceed the daily limit of 120 parts per billion by volume in all three regions, namely, Kao-hsiung City, Kso-hsiung County, and P'ing-tung County. The monthly means of daily maximum 1-hr O3 concentrations exhibit distinct seasonal variations, with a bimodal form with the maxima in autumn and late winter to the middle of spring and a minimum in summer. The long-term variations in the annual means of hourly O3 concentrations in the three regions exhibit increasing trends. These increases in O3 are associated with the decline in ambient concentrations of nitrogen oxides and nonmethane hydrocarbons. High O3 episodes occur most often in autumn and most rarely in summer. The seasonal mean mixing heights in descending order follow the order of spring, summer, autumn, and winter. Meteorological parameters in autumn and winter indicate that the ground-level O3 tends to accumulate and trigger a high O3 episode on a warm day with sufficient sunlight and low wind in a high-pressure system, consistent with the low mixing heights in these two seasons. 相似文献
953.
954.
Model calculating annual mean atmospheric dispersion factor for coastal site of nuclear power plant 总被引:1,自引:0,他引:1
HU Er-bang YAO Ren-tai ZHANG Mao-shuan GAO Zhan-rong WANG Shu-xian CHEN Jia-yi JIA Pei-rong Liao Qi-lin 《环境科学学报(英文版)》2001,13(3):280-290
IntroductionAnatmospheredispersionfieldexperimentwasdoneonthecoastalsiteofnuclearpowerplant (NPP)intheeastpartofChinaduring 1995— 1996 Thecontentofthisexperimentincludes:hourlyobservationofwindandtemperatureonthetowerof10 0m ;Observationofsurfacewindandseeandl… 相似文献
955.
V. K. Garg Y. K. Yadav Aleenjeet Sheoran Subhash Chand Priya Kaushik 《The Environmentalist》2006,26(4):269-276
In India, millions of tones of livestock excreta are produced. Our study explores the potential of an epigeic earthworm Eisenia foetida to compost different livestock excreta (cow, buffalo, horse, donkey, sheep, goat and camel) into value added product (vermicompost)
at the laboratory scale. Vermicomposting resulted in lowering of pH, electrical conductivity, potassium and C:N ratio and
increase in nitrogen and phosphorus contents. Total K was lower in the final cast than in the initial feed. C:N ratios of
the vermicomposts ranged from 16.2 ± 2.17 to 75.4 ± 6.84. Microbial activity measured as dehydrogenase activity in buffalo,
donkey and camel wastes increased with time up to day 90. But in sheep and goat wastes, maximum dehydrogenase activity was
recorded on day 60 and decreased thereafter. The cocoons and hatchlings production by Eisenia foetida in different excreta were also investigated. The greatest number and biomass of hatchlings was recorded in horse excreta
followed by cow, goat and sheep excreta. Thus, cow, horse, sheep and goat excreta show potential as good substrates in vermicomposting
using Eisenia foetida, although further research is required to explore the feasibility of use of buffalo, donkey and camel excreta in combination
with cow/sheep/goat excreta. 相似文献
956.
An understanding of temporal trends in total stream‐flow (TSF), base flow (BF), and storm runoff (RO) can help in the development of water management plans for watersheds and local communities. In this study, 47 streams across Pennsylvania that were unregulated and unaffected by karst environments or coal mining were studied for flow trends and their relationships to selected climate parameters for the period 1971 to 2001. LOWESS curves for annual flow showed that almost all of the selected streams in Pennsylvania had downward trends in total TSF, BF, and RO. Using a seasonal Mann‐Kendall analysis, downward trends were significant at an α= 0.05 level for 68, percent 70 percent, and 62 percent of the streams and at an α= 0.10 level for another 19, 17, and 13 percent of the streams for TSF, BF, and RO, respectively. The ratio of BF to TSF (RBS) had significant upward trends for 34 percent of the streams at an α= 0.05 level and for another 9 percent of the streams at an α= 0.10 level, indicating that TSF decreased relative to BF for more than 40 percent of the streams during the previous 30 years. Downward trends in TSF, BF, and RO were most common for the months of June, July, and December. Trend analyses using monthly and annual total precipitation and mean temperature showed some association between climate and the streamflow trends, but Spearman's correlation and partial Mann‐Kendall analyses revealed that the trends in TSF, BF, and RO could not be explained by trends in precipitation and temperature alone, and thus urbanization and development may have played a role. 相似文献
957.
Relationship between chlorine consumption and chlorination by-products formation for model compounds 总被引:1,自引:0,他引:1
The objective of this research is to investigate the relationship between chlorine decay and the formations of disinfection by-products (DBP), including trichloromethane (TCM) and chloroacetic acid (CAA) in the presence of four model compounds, i.e., resorcinol, phloroglucinol, p-hydroxybenzoic acid, and m-hydroxybenzoic acid. The chlorine degradation in model compounds with OH and/or COOH functional groups were rapid after chlorination. The TCM yields of carboxylic group substituted compounds (3-hydroxybenzoic acid [3-HBA], 4-hydroxybenzoic acid [4-HBA]) were found to be lower than that of the m-dihydroxy substituted compounds. Phloroglucinol, with one more OH substitution group than resorcinol, tends to form significant amounts of CAA after chlorination. However, it was observed that with the COOH substitution of 3-HBA and 4-HBA tend to exhibit more CAA formation potential than resorcinol. The developed parallel second and first-order reaction model for chlorine demand has been successfully utilized for TCM, CAA and DBP formation modeling. A high correlation between CAA and TCM was observed for the model compounds. 相似文献
958.
959.
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a widely spread environmental pollutant. Homopoietic system is one of the targets of TCDD in laboratory animals including monkeys. The present study is the hemopoietic cell kinetics in mice, from the severe depression in cellularity of bone marrow and CFU-GM, to their recovery after the intraperitoneal injection of high dosage of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD). The bone-marrow cellularity and CFU-GM were severely decreased to 37.8% and 48% of the control, respectively until day 1 after exposure to TCDD. They were, however, soon recovered, even overshot the control value. Subsequently, they tended to show decrease and oscillation again to and under the control value. In conclusion, our cell kinetic study has proven the oscillation in bone-marrow cellularity and CFU-GM during the recovery period, of which the observation seems to be useful to extend our understanding in the hematotoxicity of TCDD. 相似文献
960.
There are size-related differences in the use of feeding habitats (planktonic or benthic; oceanic or neritic) by adult female loggerhead sea turtles (Caretta caretta) within Japanese populations. We thus hypothesized that the differences may be reflected in their remigration and growth patterns, and investigated the relationships between body size and remigration intervals, growth rates, and remigration percentages, for female loggerheads nesting on a Japanese beach between 1991 and 2001. Although remigration intervals, growth rates, and remigration percentages were not significantly different among females, there were trends for longer remigration intervals and lower remigration percentages in smaller females. All females grew little. Considering these results along with previous findings, we speculated on the life-history strategy of female Japanese loggerheads.Communicated by T. Ikeda, Hakodate 相似文献