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   35143篇
  免费   301篇
  国内免费   335篇
安全科学   897篇
废物处理   1580篇
环保管理   4154篇
综合类   5102篇
基础理论   9887篇
环境理论   8篇
污染及防治   9082篇
评价与监测   2574篇
社会与环境   2291篇
灾害及防治   204篇
  2022年   304篇
  2021年   296篇
  2020年   220篇
  2019年   267篇
  2018年   576篇
  2017年   606篇
  2016年   930篇
  2015年   616篇
  2014年   913篇
  2013年   2682篇
  2012年   1411篇
  2011年   1580篇
  2010年   1288篇
  2009年   1251篇
  2008年   1404篇
  2007年   1560篇
  2006年   1383篇
  2005年   1547篇
  2004年   1686篇
  2003年   1512篇
  2002年   1072篇
  2001年   1423篇
  2000年   992篇
  1999年   596篇
  1998年   412篇
  1997年   412篇
  1996年   446篇
  1995年   470篇
  1994年   438篇
  1993年   384篇
  1992年   398篇
  1991年   361篇
  1990年   379篇
  1989年   374篇
  1988年   319篇
  1987年   296篇
  1986年   257篇
  1985年   271篇
  1984年   293篇
  1983年   276篇
  1982年   294篇
  1981年   238篇
  1980年   210篇
  1979年   260篇
  1978年   198篇
  1977年   204篇
  1976年   167篇
  1975年   161篇
  1974年   158篇
  1973年   166篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
Environment, Development and Sustainability - Land use and land cover change (LULCC) is one of the problems that the world has been facing for the last few decades despite political attention....  相似文献   
142.
Environment, Development and Sustainability - This study describes the results of groundwater table variation in Thanjavur District before and after the monsoon seasons. Groundwater-level data...  相似文献   
143.
Russian Journal of Ecology - Abstract—We tested a hypothesis about the different abilities of alien and native plants to form arbuscular mycorrhizae. The studies were carried out in the...  相似文献   
144.
Rate-temperature responses in scyphozoan medusae and polyps   总被引:1,自引:0,他引:1  
The effects of temperature on oxygen consumption and spontaneous rhythmic activity have been investigated in various stages of the life histories of 3 species of jellyfish from the Chesapeake Bay, USA. All 3 species clearly show the ability to acclimate positively to temperature change. Thermal sensitivity of metabolism in the winter medusa Cyanea capillata fulva is fairly low at temperature intervals which are experienced in nature. Polyps of the two summer medusae, Chrysaora quinquecirrha and Aurelia aurita, show reduced metabolic sensitivity at temperatures normally accompanying high developmental activity and the onset of strobilation.  相似文献   
145.
146.
147.
148.
149.
150.
The distribution and sources of organochlorine pesticides (OCPs) in air and surface waters were monitored in Nairobi City using triolein-filled semipermeable membrane devices (SPMDs). The SPMDs were extracted by dialysis using n-hexane, followed by cleanup by adsorption chromatography on silica gel cartridges. Sample analysis was done by GC-ECD and confirmed by GC–MS. Separation of means was achieved by analysis of variance, followed by pair-wise comparison using the t-test (p≤ 0.05). The total OCPs ranged between 0.018 – 1.277 ng/m3 in the air and <LOD – 1391.000 ng/m3 in surface waters. Based on the results, the means of Industrial Area, Dandora and Kibera were not significantly different (p≤ 0.05), but were higher (p≤ 0.05) than those of City square and Ngong’ Forest. The results revealed non-significant (p≤ 0.05) contribution of long-range transport to OCP pollution in Nairobi City. This indicated possible presence of point sources of environmental OCPs in the city. The water-air fugacity ratios indicated that volatilization and deposition played an important role in the spatial distribution of OCPs in Nairobi City. This indicated that contaminated surface waters could be major sources of human exposure to OCPs, through volatilization. The incremental lifetime cancer risks (ILCR) determined from inhalation of atmospheric OCPs were 2.3745  ×  10?13 – 1.6845  ×  10?11 (adult) and 5.5404  ×  10?13 – 3.9306  ×  10?11 (child) in the order: Dandora > Kibera > Industrial Area > City Square > Ngong’ Forest. However, these were lower than the USEPA acceptable risks, 10?6 – 10?4. This study concluded that atmospheric OCPs did not pose significant cancer risks to the residents.  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