全文获取类型
收费全文 | 19935篇 |
免费 | 1566篇 |
国内免费 | 3260篇 |
专业分类
安全科学 | 3061篇 |
废物处理 | 430篇 |
环保管理 | 3074篇 |
综合类 | 11599篇 |
基础理论 | 1744篇 |
环境理论 | 9篇 |
污染及防治 | 1373篇 |
评价与监测 | 1397篇 |
社会与环境 | 1174篇 |
灾害及防治 | 900篇 |
出版年
2024年 | 75篇 |
2023年 | 308篇 |
2022年 | 550篇 |
2021年 | 766篇 |
2020年 | 770篇 |
2019年 | 602篇 |
2018年 | 545篇 |
2017年 | 720篇 |
2016年 | 834篇 |
2015年 | 882篇 |
2014年 | 964篇 |
2013年 | 1171篇 |
2012年 | 1356篇 |
2011年 | 1473篇 |
2010年 | 1031篇 |
2009年 | 1139篇 |
2008年 | 861篇 |
2007年 | 1325篇 |
2006年 | 1353篇 |
2005年 | 1168篇 |
2004年 | 1036篇 |
2003年 | 1007篇 |
2002年 | 854篇 |
2001年 | 730篇 |
2000年 | 674篇 |
1999年 | 597篇 |
1998年 | 386篇 |
1997年 | 330篇 |
1996年 | 228篇 |
1995年 | 213篇 |
1994年 | 181篇 |
1993年 | 159篇 |
1992年 | 106篇 |
1991年 | 66篇 |
1990年 | 51篇 |
1989年 | 26篇 |
1988年 | 31篇 |
1987年 | 25篇 |
1986年 | 11篇 |
1985年 | 12篇 |
1984年 | 25篇 |
1983年 | 17篇 |
1982年 | 14篇 |
1981年 | 11篇 |
1980年 | 15篇 |
1979年 | 15篇 |
1974年 | 5篇 |
1973年 | 9篇 |
1972年 | 7篇 |
1971年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
乌鲁木齐市汽车尾气排污现状及防治对策探讨 总被引:1,自引:0,他引:1
对乌鲁木齐市在用车辆进行了路抽检调查,通过大量数据分析,得出乌鲁木齐市目前汽车尾气排放情况仍令人担忧,治理工作不容忽视。 相似文献
93.
94.
A ten year summary of concurrent ambient water column and sediment toxicity tests in the Chesapeake Bay watershed: 1990-1999 总被引:1,自引:0,他引:1
The goal of this study was to identify the relative toxicity ofambient areas in the Chesapeake Bay watershed by using a suiteof concurrent water column and sediment toxicity tests at seventy-five ambient stations in 20 Chesapeake Bay rivers from1990 through 1999. Spatial and temporal variability was examinedat selected locations throughout the 10 yr study. Inorganicand organic contaminants were evaluated in ambient water andsediment concurrently with water column and sediment tests toassess possible causes of toxicity although absolute causalitycan not be established. Multivariate statistical analysis wasused to develop a multiple endpoint toxicity index (TOX-INDEX) at each station for both water column and sediment toxicity data. Water column tests from the 10 yr testing period showed that49% of the time, some degree of toxicity was reported. The mosttoxic sites based on water column results were located inurbanized areas such as the Anacostia River, Elizabeth River andthe Middle River. Water quality criteria for copper, lead,mercury, nickel and zinc were exceeded at one or more of thesesites. Water column toxicity was also reported in localizedareas of the South and Chester Rivers. Both spatial and temporalvariability was reported from the suite of water column toxicitytests. Some degree of sediment toxicity was reported from 62% of the tests conducted during the ten year period. The ElizabethRiver and Baltimore Harbor stations were reported as the most toxic areas based on sediment results.Sediment toxicity guidelines were exceeded for one or more of thefollowing metals at these two locations: arsenic, cadmium,chromium, copper, lead, nickel and zinc. At the Elizabeth Riverstations nine of sixteen semi-volatile organics and two of sevenpesticides measured exceeded the ER-M values in 1990. Ambientsediment toxicity tests in the Elizabeth River in 1996 showedreduced toxicity. Various semi-volatile organics exceeded the ER-M values at a number of Baltimore Harbor sites; pyrene anddibenzo(a,h)anthracene were particularly high at one of thestations (Northwest Harbor). Localized sediment toxicity was alsoreported in the Chester, James, Magothy, Rappahannock, andPotomac Rivers but the link with contaminants was not determined.Both spatial and temporal variability was less for sedimenttoxicity data when compared with water column toxicity data. Acomparison of water column and sediment toxicity data for thevarious stations over the 10 yr study showed that approximatelyhalf the time agreement occurred (either both suite of testsshowed toxicity or neither suite of tests showed toxicity). 相似文献
95.
Fagundez LA Fernández VL Marino TH Martín I Persano DA Rivarola Y Benítez M Sadañiowski IV Codnia J Zalts A 《Environmental monitoring and assessment》2001,71(1):61-70
Passive diffusion samplers were employed in San Miguel(Buenos Aires Metropolitan Area) for a preliminary airpollution monitoring. The highest loads were observedin downtown, compared with an urban background site.Total suspended particulate matter (TSPM) varied from0.257 to 0.033 mg cm-2 month-1; dust was examinedfor particle nature and size distribution. A similartrend was observed for nitrogen dioxide (NO2) andTSPM spatial distribution, suggesting that traffic isthe major pollution source. Sulphur dioxide (SO2)values were low and rather homogeneous. Levels for theinvestigated pollutants are below EPA's guide linevalues. Geographic (flat area, near to Rio de LaPlata) and climatologic factors (rainfalls andvariable wind directions) contribute to disperse pollutants. 相似文献
96.
Ambient Air Quality Monitoring Network Design for Assessing Human Health Impacts from Exposures to Airborne Contaminants 总被引:1,自引:0,他引:1
Existing methods of establishing ambientair quality monitoring networks typically evaluateonly parameters related to ambient concentrations ofthe contaminant(s) of interest such as emissionsource characteristics, atmospheric transport anddispersion, secondary reactions, depositioncharacteristics, and local topography. However,adverse health risks from exposures to airbornecontaminants are a function of the contaminant andthe anatomic and physiologic characteristics of theexposed population. Thus, ambient air qualitymonitoring networks designed for the protection ofpublic health or for epidemiological studiesevaluating adverse health impacts from exposures toambient air contaminants should account for bothcontaminant characteristics and human healthparameters. A methodology has been establishedwhich optimizes ambient air quality monitoringnetworks for assessments of adverse human healthimpacts from exposures to airborne contaminants byincorporating human health risk assessmenttechniques. The use of risk assessment techniquesas the basis for designing ambient air qualitymonitoring networks will help to target limitedfinancial and human resources to evaluate humanhealth risks from exposures to airbornecontaminants. 相似文献
97.
We propose a modelling framework for the design of a Pigouvian effluent tax, in an environmental management problem implicating
several economic agents located in a river basin. The proposed charging system allows for the agents' geographical position
relative to the river's sections, at which environmental standards are to be enforced, and takes into account the possible
different market structures within which the agents are operating. In particular, we consider industrial agents competing
on an oligopolistic market, and a set of farmers acting as price takers on a large market. A regional authority's goal is
to induce agents to some sort of cooperation which would result in the satisfaction of the common environmental constraints.
The economic process on one side, and the pollution transport and accumulation on the other, constitute two dynamic processes
in two different time scales. As the economic process is much slower than the other process we can neglect the latter's transients
and concentrate on the time invariant steady state solutions to the transportation equation. The model thus constructed has
some noncooperative game and optimal control problem's features with space being the ‘running’ variable.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
98.
工作场所空气中硫酸雾(SO3)的分析 总被引:1,自引:0,他引:1
王连弟 《环境监测管理与技术》1997,9(3):36-37
采用碘量法测定工作场所空气中的三氧化硫及硫酸雾,三氧化硫及硫酸雾经中性水吸收后与碘化钾和碘酸钾反应,析出的碘与淀粉指示剂作用产生蓝色,进行比色测定。 相似文献
99.
A study on the orbit of air temperature movement 总被引:1,自引:0,他引:1
Zong-Chang Yang 《Environmental Modeling and Assessment》2007,12(2):131-143
In this paper, we describe an air temperature movement by mapping its time series to the polar coordinates: the value of the
time series is plotted on the radial coordinate and the time on the angular coordinate. In this way, both the yearly and daily
air temperature movements from five different locations of China are used to demonstrate that, in an intuitionistic view,
air temperature movement is neither random nor chaotic, but has its own orbit. We then propose an elliptic orbit model for
the air temperature movement. Our proposed model provides quite good results when it is applied to the evaluation of yearly
air temperature movements in eight locations in various parts of the world, and the evaluation of daily air temperature movements
in five locations in Hunan Province of China on December 17, 2005. Results show that our approach provides a concise and helpful
model for air temperature analysis. 相似文献
100.
根据塔里木油田1993-1996年环境空气监测数据,对其环境空气质量状况进行了分析和评价。 相似文献