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   20281篇
  免费   234篇
  国内免费   155篇
安全科学   544篇
废物处理   848篇
环保管理   2563篇
综合类   3546篇
基础理论   4857篇
环境理论   18篇
污染及防治   5521篇
评价与监测   1384篇
社会与环境   1251篇
灾害及防治   138篇
  2023年   111篇
  2022年   237篇
  2021年   295篇
  2020年   178篇
  2019年   208篇
  2018年   337篇
  2017年   393篇
  2016年   561篇
  2015年   414篇
  2014年   623篇
  2013年   1726篇
  2012年   780篇
  2011年   964篇
  2010年   734篇
  2009年   745篇
  2008年   894篇
  2007年   931篇
  2006年   829篇
  2005年   671篇
  2004年   626篇
  2003年   602篇
  2002年   552篇
  2001年   598篇
  2000年   462篇
  1999年   269篇
  1998年   219篇
  1997年   206篇
  1996年   225篇
  1995年   237篇
  1994年   229篇
  1993年   215篇
  1992年   221篇
  1991年   210篇
  1990年   212篇
  1989年   178篇
  1988年   153篇
  1987年   133篇
  1986年   160篇
  1985年   162篇
  1984年   161篇
  1983年   166篇
  1982年   159篇
  1981年   165篇
  1980年   153篇
  1979年   145篇
  1978年   110篇
  1977年   123篇
  1974年   109篇
  1973年   92篇
  1972年   107篇
排序方式: 共有10000条查询结果,搜索用时 609 毫秒
571.
Collaborative monitoring over broad scales and levels of ecological organization can inform conservation efforts necessary to address the contemporary biodiversity crisis. An important challenge to collaborative monitoring is motivating local engagement with enough buy-in from stakeholders while providing adequate top-down direction for scientific rigor, quality control, and coordination. Collaborative monitoring must reconcile this inherent tension between top-down control and bottom-up engagement. Highly mobile and cryptic taxa, such as bats, present a particularly acute challenge. Given their scale of movement, complex life histories, and rapidly expanding threats, understanding population trends of bats requires coordinated broad-scale collaborative monitoring. The North American Bat Monitoring Program (NABat) reconciles top-down, bottom-up tension with a hierarchical master sample survey design, integrated data analysis, dynamic data curation, regional monitoring hubs, and knowledge delivery through web-based infrastructure. NABat supports collaborative monitoring across spatial and organizational scales and the full annual lifecycle of bats.  相似文献   
572.
Environmental Science and Pollution Research - This work describes the production/characterization of low molar mass chitosan nanoparticles derived from waste shrimp shells (SSC), as well as from a...  相似文献   
573.
Environmental Science and Pollution Research - It is well known that road transport emits various trace elements into the environment, which are deposited in soils in the vicinity of roads,...  相似文献   
574.
Environmental Science and Pollution Research - The aim of the study was to determine if gold-mining activities could impact the mercury (Hg) concentrations and isotopic signatures in freshwater...  相似文献   
575.
Environmental Science and Pollution Research - Potentially toxic elements (PTEs) are of great concern in steel mill wastes. Therefore, in order to use them as potential fertilizers in soil, risk...  相似文献   
576.
Environmental Science and Pollution Research - On-site small-scale sanitation is common in rural areas and areas without infrastructure, but the treatment of the collected fecal matter can be...  相似文献   
577.
Environmental Science and Pollution Research - Glyphosate is the most used herbicide worldwide. Many studies have reported glyphosate risks to aquatic organisms of different trophic levels....  相似文献   
578.

The presence of potentially hazardous elements (PHEs) in playground soils is generally associated with anthropogenic sources such as vehicle traffic, industries, construction sites, and biomass burning. Studies indicate that PHEs are harmful to human health and may even be carcinogenic. Therefore, the aim of this study was to evaluate the physicochemical, morphological, and mineralogical properties of soil samples from three public playgrounds located in the cities of Bogota, Medellin, and Barranquilla. Besides, the possible impacts caused by the aerodynamics of particles in Colombian cities were verified. The morphology, composition, and structure of the nanoparticles (NPs) (< 100 nm) present in these soils were evaluated by field emission scanning electron microscopy (FE-SEM) equipped with high-precision field emission (FE) and high-resolution transmission electron microscopy (HR-TEM). Soil samples were predominantly feldspar, quartz, and, to a lesser extent, clay minerals, carbonates, and hematites. The average content of PHEs was anthropogenically enriched in relation to the upper continental crust. As and Sn showed a large spatial variation, indicating the influence of local sources, such as vehicle traffic and industries. There is an inverse relationship between the total concentrations of some elements and their leachable fractions. The accumulation of traffic-derived PHEs has a negative impact on human health and the environment, which is alarming, especially for elements such as Pb, Sb, or As. Therefore, the presence of PHEs should receive greater attention from public health professionals, and limits should be set and exposures controlled. This study includes the construction of a baseline that provides basic information on pollution, its sources, and exposure routes for humans in the vicinity of Colombia’s major cities, characterized by their increasing urbanization and industrialization.

  相似文献   
579.

Natural products may be applied in a wide range of domains, from agriculture to food and pharmaceutical industries. In this study, the antioxidant properties and the capacity to inhibit some enzymatic activities of Euphorbia resinifera and Euphorbia officinarum aqueous extracts and honeys were assessed. The physicochemical characteristics were also evaluated. Higher amounts of iron, copper and aluminium were detected in E. officinarum honey, which may indicate environmental pollution around the beehives or inadequate storage of honey samples. This honey sample showed higher amounts of total phenols and better capacity for scavenging superoxide anion free radicals and DPPH free radicals as compared with E. resinifera honey, but poorer capacity for inhibiting lipoxygenase, acetylcholinesterase, tyrosinase and xanthine oxidase. The ratio plant mass:solvent volume (1:100) and extraction time (1 - 2 h) were associated with higher total phenols and better antioxidant activities and lipoxygenase, acetylcholinesterase and tyrosinase inhibitory activities, regardless of the plant species. The aqueous extracts had systematically higher in vitro activities than the respective honey samples.

  相似文献   
580.
Environmental Science and Pollution Research - A theoretical physicochemical and thermodynamic investigation of the adsorption of heavy metals Zn2+, Cd2+, Ni2+, and Cu2+on carbon-based adsorbents...  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