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   1410篇
  免费   68篇
  国内免费   524篇
安全科学   81篇
废物处理   87篇
环保管理   87篇
综合类   808篇
基础理论   247篇
污染及防治   562篇
评价与监测   52篇
社会与环境   45篇
灾害及防治   33篇
  2023年   26篇
  2022年   87篇
  2021年   88篇
  2020年   47篇
  2019年   48篇
  2018年   54篇
  2017年   66篇
  2016年   72篇
  2015年   79篇
  2014年   115篇
  2013年   120篇
  2012年   104篇
  2011年   121篇
  2010年   88篇
  2009年   103篇
  2008年   106篇
  2007年   92篇
  2006年   67篇
  2005年   50篇
  2004年   49篇
  2003年   51篇
  2002年   31篇
  2001年   46篇
  2000年   44篇
  1999年   37篇
  1998年   42篇
  1997年   23篇
  1996年   26篇
  1995年   20篇
  1994年   17篇
  1993年   19篇
  1992年   8篇
  1991年   16篇
  1990年   15篇
  1989年   7篇
  1988年   10篇
  1987年   2篇
  1986年   2篇
  1985年   2篇
  1983年   1篇
  1981年   1篇
排序方式: 共有2002条查询结果,搜索用时 15 毫秒
91.
历史的经验告诉我们,就环境论环境不能解决环境问题。本文从分析当今时代的特点出发,剖析了我国环境污染形势,最后论述如何走出环境污染的怪圈.经济增长不等于经济发展,但可持续发展却是永恒的主题.解决环境问题必须改变传统发展战略,发展是硬道理,但我们讲的发展是全社会的持续、协调、全面发展。解振华局长说:“工业污染是环境污染的主要来源”。经济增长的源泉在企业,经济增长的动力是企业利益,经济增长的压力是市场的竞争,经济增长的持续是协调发展。只顾产值不讲效益的观念必须改变,环境问题的解决必须和国家的经济发展、科学技术、社会稳定统一考虑,必须纳入国家整体战略,环境问题才能进步解决。  相似文献   
92.
数据代表性是指监测结果在表征被监测对象特性时所能达到的真实程度;样品代表性是指局部体现整体时所能达到的真实程度。加密监测是重点原调查的质量基础,不能简化行事。监督性监测中,通过测定流量比例混合样来获取总量控制所必需的漉量加权平均值浓度数据,并以此来减小工作量。为满足浓度控制需要,时间—浓度确定型废水的峰浓度样应单独测定。  相似文献   
93.
长江流域的鱼类资源及其保护对策   总被引:40,自引:7,他引:33  
长江水系的鱼类约有300种,其中鲤科鱼类占半数以上,主要的经济鱼类多数属于鲤科。对不同江段的鱼类资源作了简介,并提出了相应的保护措施。上游江段以维护生物多样性,保护特有种为主,需要建立鱼类自然保护区;中游应保证主要经济鱼类的自然繁殖条件,加强珍稀鱼类的人工繁殖放流工作,同时对湖泊幼鱼资源进行保护;下游应注意保持江水质量,严格遵守工业废水排放标准;河口江段应规定幼鲟保护期,建议每年6月15日至7月31日停止一切损害幼鲟资源的渔捞作业。  相似文献   
94.
In April 1998, two intense dust storms were generated in CentralAsia and transported eastward across East Asia (15 and 19 April). This article presents the chemical characterization ofHong Kong (HK) aerosols during the dust storms. During the 15 Aprildust storm, hourly respiratory suspended particles (RSP)(particle diameter smaller than 10 m) concentrationsmonitored at 7 sites in Hong Kong reached the peak valuessynchronously between 9 and 11 a.m. on 17 April, in which thehighest concentration was 267 g m-3. Analysis ofthe RSP samples showed that concentrations of crustalelements (Ba, Ca, Cd, Cr, Fe, Mg, K+) and anthropogenicspecies (As, Ni, Pb, Zn, NH4 +, NO3 -,SO4 2- and total carbon) were substantiallyenhanced. Enhancement of these species was more than afactor of 2 to 14 relative to the non dust period. The totalcarbon content was high, at 59 g m-3 (notincluding carbonate), and the enrichment factors of Asand Pb on 17 April were 122 and 117, respectively. Thisimplied that anthropogenic materials together with mineraldust were transported to HK from Mainland China. Based onmaterial balance calculations, mineral dust contributed41% to the observed RSP mass on 17 April, which was 2 times thatof the nondust sample (22%). From the 5-day backwardtrajectory analysis, this storm was transported directlyfrom Northwest China to HK. However, there was nocorresponding observation for the 19 April dust stormaerosol. Consequently, 15 April storm had stronger impact onHK's atmosphere than 19 April storm. Compared to the HK AirQuality Objective, 15 April dust storm did not cause seriousair pollution in HK.  相似文献   
95.
A Level III fugacity model was applied to characterize the transfer processes and environmental fate of benzo[a]pyrene in wastewater-irrigated areas of Tianjin, China. The physical-chemical properties and transfer parameters of benzo[a]pyrene were used in the model and the concentration distribution of benzo[a]pyrene in sediment, soil, water, air, fish, and crop compartments, as well as transfer fluxes across the compartments, were then derived under steady-state assumptions. The calculated results were compared with monitoring data for air, soil, water, and sediment collected from the literature. The results indicate that there was generally good agreement and the differences were within an order of magnitude for air, soil, and sediment. The concentration of benzo[a]pyrene in the ambient air in the area was very low with a majority present sorbed to aerosol. In the water compartment, approximately 70% of benzo[a]pyrene dissolved in water phase. Relatively high concentrations of the compound were found in the soil and sediment, with the soil serving as the dominant sink in the area. Benzo[a]pyrene, with a slow metabolic rate, was found to accumulate in fish in the area.  相似文献   
96.
Changes of copper speciation in maize rhizosphere soil   总被引:1,自引:0,他引:1  
Chemical forms of copper in the rhizosphere and bulk soil of maize were investigated using rhizobox cultivation and sequential extraction techniques. The copper accumulations were also determined. The results demonstrated that there were continuous changes in copper fractionation within the maize rhizosphere. Initially, the amount of exchangeable copper increased before dropping below the initial level after 40 days or so. Carbonate associated copper followed a similar trend of change, but with a slower pace than the exchangeable copper. The increase in carbonate associated copper only become evident after 30 days, with the net loss occurring after 60 days. There were also initial increases in oxide bound copper as well as decreases in the organic matter associated copper, both followed by a turnover after 40-50 days. The accumulation of copper in the maize plant was found to be biomass dependent. The amount of accumulated copper absorbed in the plant material exceeded the initial quantity of the exchangeable copper in the soil, revealing a transformation from less bioavailable to more bioavailable fractions. During cultivation, decreases in redox potential and increases in pH, dissolved organic carbon (DOC), and microbial activity in the maize rhizosphere were observed. The change in copper speciation may result from root-induced changes in DOC, redox potential, and microbial activity in the rhizosphere.  相似文献   
97.
气相色谱法测定水和废水中丙烯腈   总被引:2,自引:0,他引:2  
本文通过采用气相色谱法,以GDX-502为固定相,FID为检测器测定水和废水中的丙烯腈,精密度和回收率高.方法简便易行,能满足行业废水和地面水的监队是水和废水中丙烯腈分析的较理想方法。  相似文献   
98.
对坑道中的尘毒进行了测试,并根据测试结果提出了一些建议。  相似文献   
99.
In China, although improvements to the pesticide registration process have beenmade in last thirty years, no occupational exposure data are required to obtain a commercial license for a pesticide product. Consequently, notably little research has been conducted to establish an exposure assessment procedure in China. The present study monitored the potential dermal operator exposure from knapsack electric sprayer wheat field application of imidacloprid in Liaocheng City, Shandong Province and in Xinxiang City, Henan Province, China, using whole-body dosimetry. The potential inhalation exposure was determined using a personal air pump and XAD-2 sample tubes. The analytical method was developed and validated, including such performance parameters as limits of detection and quantification, linear range, recovery and precision. The total potential dermal and inhalation exposures were 14.20, 16.80, 15.39 and 20.78 mL/hr, respectively, for the four operators in Liaocheng and Xinxiang, corresponding to 0.02% to 0.03% of the applied volume of spray solution. In all trials, the lower part (thigh, lower leg) of the body was the most contaminated, accounting for approximately 76% to 88% of the total exposure. The inhalation exposure was less than 1% of the total exposure. Such factors as the application pattern, crop type, spray equipment, operator experience and climatic conditions have been used to explain the exposure distribution over the different parts of the body. As indicated by the calculated Margin of Exposure, the typical wheat treatment scenarios when a backpack sprayer was used are considered to be safe in terms of imidacloprid exposure.  相似文献   
100.
A 1-dodecanethiol-based phase-transfer protocol is developed for the extraction of noble metal ions from aqueous solution to a hydrocarbon phase, which calls for first mixing the aqueous metal ion solution with an ethanolic solution of 1-dodecanethiol, and then extracting the coordination compounds formed between noble metal ions and 1-dodecanethiol into a non-polar organic solvent. A number of characterization techniques, including inductively coupled plasma atomic emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis demonstrate that this protocol could be applied to extract a wide variety of noble metal ions from water to dichloromethane with an efficiency of >96%, and has high selectivity for the separation of the noble metal ions from other transition metals. It is therefore an attractive alternative for the extraction of noble metals from water, soil, or waste printed circuit boards.  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