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   587篇
  免费   21篇
  国内免费   5篇
安全科学   30篇
废物处理   29篇
环保管理   151篇
综合类   63篇
基础理论   124篇
污染及防治   142篇
评价与监测   25篇
社会与环境   19篇
灾害及防治   30篇
  2022年   3篇
  2021年   8篇
  2020年   15篇
  2019年   11篇
  2018年   16篇
  2017年   11篇
  2016年   19篇
  2015年   23篇
  2014年   20篇
  2013年   47篇
  2012年   22篇
  2011年   28篇
  2010年   22篇
  2009年   24篇
  2008年   25篇
  2007年   31篇
  2006年   21篇
  2005年   24篇
  2004年   18篇
  2003年   21篇
  2002年   30篇
  2001年   9篇
  2000年   10篇
  1999年   9篇
  1998年   10篇
  1997年   9篇
  1996年   7篇
  1995年   4篇
  1994年   9篇
  1993年   13篇
  1991年   4篇
  1990年   3篇
  1989年   6篇
  1988年   3篇
  1987年   2篇
  1986年   3篇
  1985年   6篇
  1984年   4篇
  1983年   3篇
  1982年   10篇
  1981年   8篇
  1980年   6篇
  1979年   7篇
  1978年   5篇
  1977年   7篇
  1976年   2篇
  1975年   2篇
  1974年   2篇
  1973年   2篇
  1971年   3篇
排序方式: 共有613条查询结果,搜索用时 78 毫秒
11.
Roof rats (Rattus rattus) and deer mice (Peromyscus maniculatus) are occasional pests of nut and tree fruit orchards throughout California and in many other parts of the USA and beyond. In general, the most practical and cost-effective control method for rodents in many agricultural environments is the use of rodenticides (toxic baits), but little or no information exists on the efficacy of current rodenticides in controlling roof rats and deer mice in orchards. Therefore, our goals were to develop an index of rodent activity to monitor efficacy of rodenticides and to subsequently test the efficacy of three California Department of Food and Agriculture rodenticide baits (0.005 % chlorophacinone treated oats, 0.005 % diphacinone treated oats, and 0.005 % diphacinone wax block) to determine their utility for controlling roof rats and deer mice in agricultural orchards. We determined that a general index using the number of roof rat photos taken at a minimum of a 5-min interval was strongly correlated to the minimum number known estimate of roof rats; this approach was used to monitor roof rat and deer mouse populations pre- and post-treatment. Of the baits tested, the 0.005 % diphacinone treated oats was most effective for both species; 0.005 % chlorophacinone grain was completely ineffective against roof rats. Our use of elevated bait stations proved effective at providing bait to target species and should substantially limit access to rodenticides by many non-target species.  相似文献   
12.
创刊于1972年12月的《文教资料简报》是由南京师范学院(1984年易名为南京师范大学)内部编印的资料性月刊,主要目的是为文科教研服务。本文回顾该刊从创办至拥有"统一刊号"、从非正式出版物至成为正式出版物的历史沿革,具体观照该刊的编辑理念,总结该刊的内容特色、文献价值及经验启示。  相似文献   
13.
Environmental Science and Pollution Research - The photo-Fenton process was performed with four radiation settings to treat clinical analysis laboratory wastewater (CALWW) from a hospital, with the...  相似文献   
14.
Caribbean pine, an economically important tree of tropical lowlands, is at risk of SO2 exposure in certain locales. Twenty-week old seedlings of Caribbean, Scots, and Virginia pine were exposed to 0.5, 1.0, and 2.0 ppm SO2 (1300, 2600, and 5200 μm?3, respectively) for 1, 2, 4, and 8 h in modified controlled-environment chambers. Severity of SO2-induced leaf necrosis for each species was related to SO2 concentration and exposure duration using a regression model. The three dose-response relationships differed in detail, but Caribbean pine seedlings were generally as sensitive to SO2 as seedlings of the two highly sensitive temperate species. In addition, 173 4-wk-old Caribbean pine seedlings were exposed to 0.5 ppm SO2 for 4 h. Over one-half of these seedlings exhibited some necrosis and over one-sixth had more than 5 percent of leaf surface necrotic. It is concluded that Caribbean pine seedlings are highly sensitive to acute doses of SO2.  相似文献   
15.
Natural emissions adopted in current regional air quality modeling are updated to better describe natural background ozone and PM concentrations for North America. The revised natural emissions include organosulfur from the ocean, NO from lightning, sea salt, biogenic secondary organic aerosol (SOA) precursors, and pre-industrial levels of background methane. The model algorithm for SOA formation was also revised. Natural background ozone concentrations increase by up to 4 ppb in annual average over the southeastern US and Gulf of Mexico due to added NO from lightning while the revised biogenic emissions produced less ozone in the central and western US. Natural PM2.5 concentrations generally increased with the revised natural emissions. Future year (2018) simulations were conducted for several anthropogenic emission reduction scenarios to assess the impact of the revised natural emissions on anthropogenic emission control strategies. Overall, the revised natural emissions did not significantly alter the ozone responses to the emissions reductions in 2018. With revised natural emissions, ozone concentrations were slightly less sensitive to reducing NOx in the southeastern US than with the current natural emissions due to higher NO from lightning. The revised natural emissions have little impact on modeled PM2.5 responses to anthropogenic emission reductions. However, there are substantial uncertainties in current representations of natural sources in air quality models and we recommend that further study is needed to refine these representations.  相似文献   
16.
The cost effectiveness of catchment-wide funding for the environmental remediation of urban waterways on the scale of a major metropolitan catchment is examined considering the typical land-use and pollutant-export characteristics of urban catchments. The evaluation is performed by comparing the effectiveness of the major stormwater treatment modes for the pollutants of concern with the proportion of pollutant export to which the measure applies. The heavy metals copper, lead, and zinc in the aqueous phase or bound to fine particulates are identified as representative of the pollutants of concern in drainage from urban catchments. The analysis suggests that these priority pollutants are predominantly (79–87%) derived from runoff from residential property and roads as disseminated urban surfaces. Analysis of a specific case of catchment-wide funding of stormwater remediation in the Sydney Harbour catchment, Australia reveals that the funding allocation cannot be expected to have achieved reductions in the loads of priority pollutants due to the types of treatment measures implemented and the sources addressed. The apportionment of funding in better accordance with the maximum potential effectiveness of stormwater treatment modes and the pollutant-export characteristics of urban catchments could thus be expected to achieve a more cost-effective result from such funding initiatives.  相似文献   
17.
18.
Effective sequestration of carbon dioxide (CO2) by algae reduces greenhouse gases effect on global warming. Algae biomass or residual such as biomeal from algae biofuel processing can be judiciously used for industrial applications such as fertilizer, animal feed, and plastics. Conversion of algae into useful plastic materials can be accomplished by extrusion technology. During algal plastic manufacturing, up to 20% thermoplastic algal blends can be fixated into or encapsulated by a non-biodegradable polymer such as polyolefin, which is known to be resistant to abiotic or biotic degradation. As a result, CO2 that is captured by algae through photosynthesis is permanently stored in a form of biomass and will not be released back into the atmosphere. The extrusion of microalgae reported in this article is a novel process to sequester CO2 and at the same time it makes a good use of the algae biomass in plastic manufacturing. Mechanical properties of the thin plastic films containing microalgae are comparable to the neat polyurethane or polyethylene films. Injection molded articles containing microalgae are dimensionally stable. However, a lower tensile strength, especially elongation at break, is observed in comparison to the neat polypropylene.  相似文献   
19.
ABSTRACT: Maryland officials have identified stormwater utilities as a potential method of financing programs to control nutrients in urban stormwater runoff that are proposed in Maryland's Chesapeake Bay Nutrient Reduction Plan. This paper reviews a number of issues related to the equity, efficiency and acceptability of user charge schemes. Overall, charges are found to be preferable to property taxes from both equity and efficiency perspectives. In addition, evidence suggests that elected officials will support creation of utilities. Obstacles to the implementation of utilities are identified.  相似文献   
20.
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