首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   222篇
  免费   0篇
  国内免费   5篇
安全科学   4篇
废物处理   19篇
环保管理   8篇
综合类   68篇
基础理论   41篇
污染及防治   66篇
评价与监测   10篇
社会与环境   11篇
  2023年   2篇
  2021年   1篇
  2020年   3篇
  2019年   1篇
  2018年   3篇
  2017年   6篇
  2016年   3篇
  2015年   6篇
  2014年   6篇
  2013年   19篇
  2012年   5篇
  2011年   16篇
  2010年   7篇
  2009年   15篇
  2008年   13篇
  2007年   19篇
  2006年   12篇
  2005年   8篇
  2004年   10篇
  2003年   7篇
  2002年   9篇
  2001年   7篇
  2000年   4篇
  1998年   3篇
  1997年   2篇
  1995年   4篇
  1994年   5篇
  1993年   2篇
  1992年   3篇
  1990年   2篇
  1989年   3篇
  1988年   2篇
  1987年   1篇
  1985年   2篇
  1982年   2篇
  1980年   1篇
  1978年   1篇
  1977年   1篇
  1973年   1篇
  1970年   1篇
  1966年   2篇
  1964年   2篇
  1959年   1篇
  1958年   1篇
  1957年   2篇
  1956年   1篇
排序方式: 共有227条查询结果,搜索用时 31 毫秒
91.
92.
93.
94.
The amounts of enzyme proteins of peroxisomal β-oxidation in fibroblasts and chorionic villous cells from infants with Zellweger syndrome and in fibroblasts, amniocytes, and chorionic villi from healthy controls were measured by immunoblot analysis. Immunoreactive proteins of peroxisomal acyl-CoA oxidase and 3-ketoacyl-CoA thiolase were absent in fibroblasts and chorionic villous cells from the patients, yet these enzyme proteins were present in fibroblasts, cultured amniocytes, and chorionic villi from the normal controls. These results show that immunoblot analysis of peroxisomal β-oxidation enzymes in amniocytes and chorionic villous cells is of potential value for the prenatal detection of Zellweger syndrome.  相似文献   
95.
96.
Dimethylamine was found to be nitrosated photochemically in aqueous solution containing nitrite both by the irradiation with a high pressure mercury lamp and by the exposure to sunlight to give nitrosodimethylamine, a well-known carcinogen. The nitrosation occurred more readily at alkaline pH than at acidic and neutral pH. These findings suggest that nitrosodimethylamine is produced photochemically under natural environmental conditions.  相似文献   
97.
Total column abundances of CO, HCN, C2H6, and C2H2 have been retrieved from infrared solar spectra observed at Moshiri (44.4°N) and Rikubetsu (43.5°N) in northern Japan from 1997 to 2005. The spectra were recorded with high spectral resolution ground-based Fourier transform infrared (FTIR) spectrometers and total column abundances were calculated by SFIT1 version 1.09e. Deviations of these species relative to their seasonal mean values (ΔCO, ΔHCN, ΔC2H6, and ΔC2H2) were derived, which showed short-time enhancements in 1998, 2002, and 2003. Good correlations among ΔCO, ΔHCN, ΔC2H6, and ΔC2H2 in a few months of each year were seen. Since the number of forest fires in Siberia had large enhancements in 1998, 2002, and 2003, trajectory analyses were performed in order to assess the influence of forest fires and it was confirmed that air masses passing over the location of burning points in Siberia reached Moshiri and Rikubetsu. This paper shows that enhancements of these species were driven by biomass burning in Siberia.  相似文献   
98.
1 IntroductionSolid phasemicro extraction (SPME)asasimpleandrapidextractiontechniqueiswidelyusedinvariousareasforextractingdiluteanalytesfromliquid ,gaseousandsolidsamplesbecauseofitshighextractionefficiency[1 ].Recently ,astirbarsorptiveextraction (SBSE…  相似文献   
99.
We report the development of a new spatially explicit individual-based Dynamic Global Vegetation Model (SEIB–DGVM), the first DGVM that can simulate the local interactions among individual trees within a spatially explicit virtual forest. In the model, a sample plot is placed at each grid box, and then the growth, competition, and decay of each individual tree within each plot is calculated by considering the environmental conditions for that tree as it relates to the trees that surround it. Based on these parameters only, the model simulated time lags between climate change and vegetation change. This time lags elongated when original biome was forest, because existing trees prevent newly establish trees from receiving enough sunlight and space to quickly replace the original vegetation. This time lags also elongated when horizontal heterogeneity of sunlight distribution was ignored, indicating the potential importance of horizontal heterogeneity for predicting transitional behavior of vegetation under changing climate. On a local scale, the model reproduced climate zone-specific patterns of succession, carbon dynamics, and water flux, although on a global scale, simulations were not always in agreement with observations. Because the SEIB–DGVM was formulated to the scale at which field biologists work, the measurements of relevant parameters and data comparisons are relatively straightforward, and the model should enable more robust modeling of terrestrial ecosystems.  相似文献   
100.
Suzuki N  Yasuda M  Sakurai T  Nakanishi J 《Chemosphere》2000,40(9-11):969-976
Long term environmental fate of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) were studied using the fugacity-based dynamic multimedia environmental fate model. New formulation about soil wind erosion into air was included into the model. Effect of process assumption, sensitivity analysis for parameters, and tentative validation against the measured sediment core analysis was performed. Mass fluxes between compartments were estimated by the dynamic modeling. From the model estimates, major mass fluxes coming from emission source were shown to go to the soil and water through wet/dry deposition, then go to degradation mainly in the soil and sediment. Major mass fluxes of TCDD and OCDD come from the impurities in CNP (Chlornitrofen) and PCP (Pentachlorophenol) directly into the soil. Consideration about multimedia environmental dynamics using the modeled mass fluxes was shown in the discussion.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号