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   16894篇
  免费   42篇
  国内免费   32篇
安全科学   174篇
废物处理   1179篇
环保管理   1927篇
综合类   1878篇
基础理论   4969篇
环境理论   2篇
污染及防治   3240篇
评价与监测   1500篇
社会与环境   2064篇
灾害及防治   35篇
  2023年   49篇
  2022年   81篇
  2021年   68篇
  2020年   42篇
  2019年   57篇
  2018年   1661篇
  2017年   1572篇
  2016年   1384篇
  2015年   217篇
  2014年   183篇
  2013年   463篇
  2012年   679篇
  2011年   1723篇
  2010年   1060篇
  2009年   924篇
  2008年   1299篇
  2007年   1694篇
  2006年   278篇
  2005年   298篇
  2004年   251篇
  2003年   369篇
  2002年   377篇
  2001年   284篇
  2000年   190篇
  1999年   120篇
  1998年   74篇
  1997年   64篇
  1996年   65篇
  1995年   72篇
  1994年   71篇
  1993年   69篇
  1992年   60篇
  1991年   65篇
  1990年   70篇
  1989年   54篇
  1988年   58篇
  1987年   57篇
  1986年   58篇
  1985年   48篇
  1984年   67篇
  1983年   60篇
  1982年   51篇
  1981年   28篇
  1980年   33篇
  1979年   32篇
  1978年   30篇
  1977年   30篇
  1976年   29篇
  1974年   31篇
  1973年   30篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Honorary Memberships are conferred by the Air Pollution Control Association on persons of widely recognized eminence in some part of the field of air pollution control or who have rendered especially meritorious service to the Association. Honorary Memberships were awarded this year to Dr. Leonard Greenburg and Mr. Milton Reizenstein, both past presidents of APCA.  相似文献   
992.
Gross average automotive exhaust emissions data collected by the Atlantic Richfield Clean Air Caravan during the summer of 1970 showed only slight geographical variations when the specific makes were ignored. When considering specific makes, significant differences were found on an average emissions basis. Vehicle population—emission distributions showed wide variations in the 50% population levels and in the percent of vehicles with emissions greater than specified values. Hydrocarbon (HC) and carbon monoxide (CO) data are given on a gross basis for the 1970, 1968-69, 1966-67, and pre-1966 model year group vehicles. Average HC and CO emissions and vehicle population-Idle emissions distribution curves are included for specific make vehicles in selected areas.  相似文献   
993.
The so-called “Six Month Study” of the air toxics problem in the United States was initiated in November 1983 by the U.S. Environmental Protection Agency. The study focused on the magnitude, nature, and distribution of the problem—three major issues that were felt to be most useful to policy makers as they attempted to define the scope and direction of a national program for controlling toxic air pollutants. The following paper is based on a draft staff report on the study released for review in September 1984. The report has not been formally released by the U.S. EPA; a final report is due by late spring of 1985.  相似文献   
994.
This paper includes results from pilot plant studies and early field demonstration units and a discussion of the application of the limestone wet scrubbing process to a low sulfur syb-butuminous coal. This latter application required the development of a hybrid two stage scrubber to enable collection of the fine particulate matter as well as removal of a significant amount of the sulfur dioxide.  相似文献   
995.
Recent investigations have indicated that ambient air CO measurements may not reflect population exposure to CO. The lack of correlation may be due to improper siting of CO instruments, improper interpretation of air quality data, or both. Studies of population carboxy-hemoglobin levels are evaluated and compared with ambient air data.,

No significant correlation was found between median population COHb levels and reductions in CO concentrations required to meet ambient air standards when calculations used to estimate reductions were based on the second highest 8 hour average. However, calculated reductions based on annual average concentrations and a trend analysis technique correlated significantly with COHb levels in five cities from which both CAMP and COHb data were available.

Studies to determine the nature of the relationship between ambient air CO concentrations and population COHb levels are needed. The differences between the Occupational Safety and Health Act Regulations and the National Ambient Air Standards for carbon monoxide should be scrutinized to determine if a redefinition of the standards or their applicability is warranted. A reevaluation of the controls necessary to make reductions in population COHb burden may be necessary.  相似文献   
996.
997.
998.
The body of information presented in this paper is directed to scientists working in atmospheric dispersion research and model development. Two years of field measurements in the coastal area of Bilbao in northern Spain show that the diffusion behavior in this complex terrain can be classified into several well defined patterns, which correspond to certain meteorological conditions. The approach taken has been the systematic use of SO2 remote sensors (COSPEC) and ground level monitors in moving platforms which are used to follow and document the flow of the air mass. Results to date show that complex reentry cycles can occur and that synoptically different flows may be indistinguishable by wind sensors at ground level (affected by channeling), and yet result in totally different observed pollution levels by a fixed monitoring network (affected by topographical effects). These results are being used to parameterize the cause-effect relationships and guide the modeling efforts in this area of complex terrain.  相似文献   
999.
The removal of SO2 with atomization of a slaked lime slurry and supplemental injection of gaseous NH3 were tested in a conventional spray dryer/baghouse system for SO2 concentrations of 2000 ppm and 3000 ppm and a 30° F approach to saturation. Results at 3000 ppm of SO2 showed an average SO2 removal efficiency of 90.3 percent at a combined stoichiometric ratio of 0.95-1.10 and an average overall sorbent utilization of 91.6 percent. The overall molal ratio of NH3/SO2 reaction was found to be 2:1 under the test conditions Particle size analyses, and EP toxicity tests were conducted on the products of the reactions.  相似文献   
1000.
ABSTRACT

The decoupling of fossil-fueled electricity production from atmospheric CO2 emissions via CO2 capture and sequestration (CCS) is increasingly regarded as an important means of mitigating climate change at a reasonable cost. Engineering analyses of CO2 mitigation typically compare the cost of electricity for a base generation technology to that for a similar plant with CO2 capture and then compute the carbon emissions mitigated per unit of cost. It can be hard to interpret mitigation cost estimates from this plant-level approach when a consistent base technology cannot be identified. In addition, neither engineering analyses nor general equilibrium models can capture the economics of plant dispatch. A realistic assessment of the costs of carbon sequestration as an emissions abatement strategy in the electric sector therefore requires a systems-level analysis. We discuss various frameworks for computing mitigation costs and introduce a simplified model of electric sector planning. Results from a “bottom-up” engineering-economic analysis for a representative U.S. North American Electric Reliability Council (NERC) region illustrate how the penetration of CCS technologies and the dispatch of generating units vary with the price of carbon emissions and thereby determine the relationship between mitigation cost and emissions reduction.  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