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   34234篇
  免费   5353篇
  国内免费   30929篇
安全科学   3093篇
废物处理   1757篇
环保管理   2990篇
综合类   40672篇
基础理论   5659篇
环境理论   2篇
污染及防治   11581篇
评价与监测   2422篇
社会与环境   1047篇
灾害及防治   1293篇
  2024年   54篇
  2023年   458篇
  2022年   1237篇
  2021年   1132篇
  2020年   1506篇
  2019年   2508篇
  2018年   2854篇
  2017年   3056篇
  2016年   2994篇
  2015年   3535篇
  2014年   4234篇
  2013年   4925篇
  2012年   4428篇
  2011年   4143篇
  2010年   3652篇
  2009年   3735篇
  2008年   3575篇
  2007年   3232篇
  2006年   2813篇
  2005年   2039篇
  2004年   1649篇
  2003年   1531篇
  2002年   1305篇
  2001年   1169篇
  2000年   1359篇
  1999年   1157篇
  1998年   927篇
  1997年   883篇
  1996年   861篇
  1995年   718篇
  1994年   499篇
  1993年   419篇
  1992年   455篇
  1991年   350篇
  1990年   290篇
  1989年   216篇
  1988年   164篇
  1987年   84篇
  1986年   87篇
  1985年   57篇
  1984年   58篇
  1983年   45篇
  1982年   48篇
  1981年   36篇
  1979年   5篇
  1976年   4篇
  1974年   3篇
  1973年   5篇
  1972年   8篇
  1971年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Di(2-ethylhexyl) phthalate (DEHP) is an omnipresent environmental chemical with widespread nonoccupational human exposure through multiple ways. Although considerable efforts have been invested to investigate mechanisms of DEHP toxicity, the key metabolic biomarkers of DEHP toxicity remain to be identified. The aim of this study was to assess the urinary metabonomics of dietary DEHP in rats using the technique of ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS). Fourteen female Wistar rats were divided into two groups and given increasing dietary doses of DEHP for 30 consecutive days. The urinary metabolite profile was studied using ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) enabled clusters to be clearly separated. Eleven principal urinary metabolites were identified as contributing to the clusters. The clusters in the positive electrospray ionization (ESI) mode were xanthurenic acid, kynurenic acid, nonate, N6-methyladenosine, and L-isoleucyl-L-proline. The clusters in the negative ESI mode were hippuric acid, tetrahydrocortisol, citric acid, phenylpropionylglycine, cPA(18:2(9Z, 12Z)/0:0), and LysoPC(14:1(9Z)). The urinary metabonomic changes indicated that exposure to dietary DEHP can affect energy-related metabolism, liver and renal function, fatty acid metabolism, and cause DNA damage in rats. The findings of this study on the urinary metabolites and metabolic pathways of DEHP may form the basis for future studies on the mechanisms of toxicity of this commonly found environmental chemical.  相似文献   
942.
Environmental Science and Pollution Research - This population-based study evaluated the short-term association between fine particulate matter (PM2.5) concentrations and its constituents and...  相似文献   
943.
Environmental Science and Pollution Research - Adsorption-desorption behavior of ionic antibiotics in natural aquatic environment is complex, especially in coastal or estuary area where influencing...  相似文献   
944.
Sun  Zhigao  Li  Jiabing  He  Tao  Ren  Peng  Zhu  He  Gao  Hui  Tian  Liping  Hu  Xingyun 《Environmental science and pollution research international》2017,24(29):23080-23095
Environmental Science and Pollution Research - Sediment samples were collected in five marshes (C1, Phragmites australis marsh; C2, P. australis and Cyperus malaccensis marsh; C3, C. malaccensis...  相似文献   
945.
Environmental Science and Pollution Research - Accurate and effective determination of the source of heavy metals is essential for the treatment of marine ecological environments. This article...  相似文献   
946.
Environmental Science and Pollution Research - Water-saving cultivation techniques have been attracting increased attention worldwide. Ridge-furrow mulching system (RFMS), as a prospective...  相似文献   
947.
Environmental Science and Pollution Research - Microbial fuel cell (MFC) is a sustainable technology to treat cattle manure slurry (CMS) for converting chemical energy to bioelectricity. In this...  相似文献   
948.

In order to remove arsenic (As) from contaminated water, granular Mn-oxide-doped Al oxide (GMAO) was fabricated using the compression method with the addition of organic binder. The analysis results of XRD, SEM, and BET indicated that GMAO was microporous with a large specific surface area of 54.26 m2/g, and it was formed through the aggregation of massive Al/Mn oxide nanoparticles with an amorphous pattern. EDX, mapping, FTIR, and XPS results showed the uniform distribution of Al/Mn elements and numerous hydroxyl groups on the adsorbent surface. Compression tests indicated a satisfactory mechanical strength of GMAO. Batch adsorption results showed that As(V) adsorption achieved equilibrium faster than As(III), whereas the maximum adsorption capacity of As(III) estimated from the Langmuir isotherm at 25 °C (48.52 mg/g) was greater than that of As(V) (37.94 mg/g). The As removal efficiency could be maintained in a wide pH range of 3~8. The presence of phosphate posed a significant adverse effect on As adsorption due to the competition mechanisms. In contrast, Ca2+ and Mg2+ could favor As adsorption via cation-bridge involvement. A regeneration method was developed by using sodium hydroxide solution for As elution from saturated adsorbents, which permitted GMAO to keep over 75% of its As adsorption capacity even after five adsorption–regeneration cycles. Column experiments showed that the breakthrough volumes for the treatment of As(III)-spiked and As(V)-spiked water (As concentration = 100 μg/L) were 2224 and 1952, respectively. Overall, GMAO is a potential adsorbent for effectively removing As from As-contaminated groundwater in filter application.

  相似文献   
949.
950.
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