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   27770篇
  免费   245篇
  国内免费   270篇
安全科学   695篇
废物处理   1192篇
环保管理   3163篇
综合类   5365篇
基础理论   7107篇
环境理论   12篇
污染及防治   7042篇
评价与监测   1975篇
社会与环境   1575篇
灾害及防治   159篇
  2022年   234篇
  2021年   196篇
  2020年   164篇
  2019年   192篇
  2018年   374篇
  2017年   418篇
  2016年   599篇
  2015年   460篇
  2014年   785篇
  2013年   2080篇
  2012年   883篇
  2011年   1205篇
  2010年   995篇
  2009年   1014篇
  2008年   1159篇
  2007年   1199篇
  2006年   1024篇
  2005年   924篇
  2004年   890篇
  2003年   897篇
  2002年   848篇
  2001年   1133篇
  2000年   775篇
  1999年   472篇
  1998年   294篇
  1997年   341篇
  1996年   355篇
  1995年   404篇
  1994年   389篇
  1993年   295篇
  1992年   333篇
  1991年   320篇
  1990年   346篇
  1989年   310篇
  1988年   283篇
  1987年   243篇
  1986年   252篇
  1985年   264篇
  1984年   247篇
  1983年   237篇
  1982年   230篇
  1981年   225篇
  1980年   185篇
  1979年   209篇
  1978年   191篇
  1977年   182篇
  1975年   163篇
  1974年   179篇
  1973年   165篇
  1972年   163篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
Environment, Development and Sustainability - Environmental deterioration and global warming has created a substantial impact on international companies to incorporate eco-friendly, green supply...  相似文献   
102.
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   
103.
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   
104.
Environment, Development and Sustainability - Drying of fish at the Sagar Island (21.7269° N, 88.1096° E) is generally carried out in open sun on the seashore on plastic sheets or mat of...  相似文献   
105.
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   
106.
107.
108.
109.
110.
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