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561.
对劳动湖受纳周边工程排水后水质的影响变化进行了分析,并给出可行性较强的建议,为此类工程排水处理提供很好的借鉴。 相似文献
562.
泛长三角地区工业污染重心演变路径及其驱动机制研究 总被引:3,自引:2,他引:1
工业污染重心路径演变是制造业转移过程中形成的环境空间响应形式,为探明经济发达的泛长三角地区工业污染重心对制造业转移的响应关系,采用2000~2010年工业污染排放数据,运用重心模型,测算各年份工业废水、废气和固废排放重心坐标,分析工业污染重心转移路径及演变规律,探讨重心演变的驱动机制.结果表明:1泛长三角地区的工业污染重心发生了偏移,其中工业固废偏移距离最大,为180.18 km,而工业废水、废气偏移的方向最大,分别为0.40°、0.17°;2工业污染重心轨迹偏移受多种因素的驱动影响.其中,安徽、江西地区重工业的高速发展加剧了污染重心朝西部偏移;以江苏、上海、浙江为代表的长三角地区产业结构优化与调整在一定程度上缓解了该地区的工业污染,安徽、江西地区高污染产业份额的增加及宽松的宏观区域政策助推了工业污染向西部地区偏移;而大规模的清洁化生产、较强的环境治理力度和完善的环保监测制度在一定程度上减缓了工业污染朝东部地区偏移. 相似文献
563.
Use of Neural Net Models to Forecast Atmospheric Pollution 总被引:1,自引:0,他引:1
The forecast of the CO and NO2 concentration levels has been obtained by the 3-layer Perceptron Neural Network with Error Backpropagation learning rule.This study shows the 3-layer Perceptron performances in relationship with the choice of the activation functions parameters (depending on the statistical values of the input/output variables).A first simulation set using data at 1 hour before has been utilized to forecast CO levels. A second simulation set with data at 12–24 hours before has been used to forecast NO2 levels.The Neural Net's performance appears to be very good both for the parameters activation function optimisation and the variables choice. 相似文献
564.
C. L. Hwang J. L. Williams R. Shojalashkari L. T. Fan 《Journal of the American Water Resources Association》1973,9(6):1159-1181
ABSTRACT: A river basin-wide water quality management system is considered. The river receives thermal as well as organic wastes. At-source treatment of these pollutants is imposed to control the basin-wide water quality. The related water quality standards are: the minimum DO concentration, the maximum allowable BOD concentration, the maximum allowable stream temperature, and the allowable rise in stream temperature. The general dynamic mathematical model representing water quality in streams and the thermal effects on BOD and DO concentrations is presented. The model is highly nonlinear in nature. The optimal management problem involving the model is solved by a recently developed nonlinear propgramming technique - the generalized reduced gradient (GRG) method. Comparison of results obtained by the GRG method vs. dynamic programming, and of results using a more realistic mathematical model vs. a simple model are presented. The analysis procedure can be applied to designing new and examining existing water quality programs, and to study the influence of alternate policies and constraints. 相似文献
565.
566.
There is abundant evidence that many factors can influence the toxicity of a particular pollutant including environmental fluctuations, season of the year, stage in life cycle, size, and sex. All of these factors should be assessed before making a judgment of the effect on natural populations. Such an assessment can be conceptualized using a simple population model through whichcontrol gates operate as functions of 1). the direct self-maintainance feedback from existing adult population biomass and 2). the recruitment of new individuals due to the maturation of larvae. By extracting general principles of organismic response to pollutants it is possible to incorporate the information into large-scale ecosystem models which would serve as working tools for answering environmental decision-making problems. 相似文献
567.
Advances in telemetry have facilitated the continuous monitoring of fish position and movement. At present, there are few examples where this approach has been applied to environmental monitoring or assessment. Here we 1) present a case study that used a fixed antenna array and continuously scanning coded receiving system to monitor the movement of radio-tagged smallmouth bass (Micropterus dolomieu) in a thermal discharge canal on Lake Erie during the winter of 1998/1999, and 2) evaluate the use of fixed telemetry arrays for environmental monitoring. Although the number of radiotagged bass in the canal decreased gradually over time, fish spent the majority of the winter in the canal. When in the canal, bass selected areas upstream of the tempering pumps where water was the warmest. This region was also high in habitat complexity, had adequate velocity refuges, and abundant forage. Despite residing in the thermal effluent throughout the winter, none of the fish monitored were observed to participate in reproductive activities in the canal in the Spring. Interestingly, during a biofouling chlorination pulse in May, 50% of radiotagged fish still residing in the canal left and did not return during the monitoring period. Utility infrastructure accessible to fish, including thermal effluents, should be considered as fish habitat and managed accordingly to minimize mortality and sublethal effects on resident and transient fish. Fixed telemetry arrays that permit the continuous monitoring of fish behavior as described in this paper are widely applicable to many issues in environmental management, monitoring, and conservation. 相似文献
568.
K.?L.?BuchananEmail author M.?R.?Evans A.?R.?Goldsmith 《Behavioral ecology and sociobiology》2003,55(1):50-59
The immunocompetence handicap hypothesis (ICHH) suggests that dominance signals are costly because their development is controlled by testosterone, which is immunosuppressive. Signal control therefore links an increased disease risk with a high quality signal. The chest bib of the house sparrow, Passer domesticus, is a signal known to be related to dominance and under control of testosterone levels. We experimentally manipulated testosterone in male sparrows during the breeding season and again independently during the post-breeding period to test whether variation in levels of testosterone could cause variation in levels of immunocompetence. There was no effect of testosterone manipulation on the cell-mediated response of birds to phytohaemagglutinin injection, nor did testosterone levels appear to affect either white blood cell ratios or red blood cell counts. In contrast, both breeding season and post-breeding season testosterone levels had significant effects upon the humoral response of the birds to sheep red blood cell injections. However, whilst testosterone during the breeding season appeared to act immunosuppressively, the role of post-breeding levels is less clear. In concordance with a previous study, there was an indication that corticosterone is involved in mediating the immunosuppressive effects of testosterone. The strength of the secondary humoral response and the cell-mediated response were negatively related suggesting the possibility of a trade-off between the different arms of the immune system. These results provide some support for the ICHH as a mechanism promoting the evolution of costly badges of status, although the results question whether the immunosuppressive cost can be mediated by testosterone at the time of badge development.Communicated by W.A.Searcy 相似文献
569.
Water and sediment toxicity assessment by use of behavioural responses of medicinal leeches 总被引:2,自引:0,他引:2
Petrauskiene L 《Environment international》2003,28(8):729-736
Behaviour has been shown to be a sensitive indicator of chemically induced stress and pathology in aquatic organisms. However, ecotoxicological investigations on medicinal leech are restricted because of scarce leech resources in natural waters. We used artificially bred medicinal leech (Hirudo medicinalis L.) of two different ages: young (1-2 weeks old) and adult leeches (1 year old). Animals were exposed to: (1) waters of Lake Drukshiai-the cooler of Ignalina Nuclear Power Plant, (2) sediments of the river Nemunas and (3) solution of heavy metal model mixture (HMMM). The following behavioural responses of leech were investigated: mobility (number of moving individuals within certain periods of time), avoidance response (number of individuals escaping the tested water or sediments) changes in body shape (contractions of some muscles, abnormal position of suckers) and feeding activity (longevity of attachment process, interruptions of feeding bouts, size of blood meal). Mobility of young leeches was increased in the tested waters of Lake Drukshiai, whereas adult leeches showed no changes of this index. Avoidance response as well as impaired feeding activity (prolonged attachment process or completely suppressed attachment reflex, decreased size of blood meal) was observed in young leeches exposed to the waters from Lake Drukshiai and in adult animals exposed to all three kind of trials mentioned above. Avoidance response and changes in mobility were recorded during the first hour of exposure to tested samples; therefore, these responses can be used as an express method for water and sediment pollution assessment. Impaired feeding activity was recorded after 1-3-week exposure: this response may be used in assessing a chronic toxicity of pollution. Medicinal leech, due to its sensitivity, simplicity of measured indices and ease of laboratory maintenance, can be used as a test organism in ecotoxicity studies. 相似文献
570.
Miles L. Burnett 《Environmental management》1998,22(2):213-224
/ In 1990, the United States officially entered the era of pollution prevention with passage of the Pollution Prevention Act. This paper analyzes EPA's implementation of the Pollution Prevention Act from its passage in 1990 to the present. It examines the barriers EPA must overcome if it is to effectively integrate pollution prevention into its existing regulatory structure, including impediments created by statutory and organizational structure, the existing relationship between EPA and the groups it regulates, the fragmented implementation scheme of national environmental regulation, the balancing of conflicting demands advanced by powerful interests, industry's economic and technical concerns, and institutional inertia. It also examines issues such as industry commitment, the limits of prevention, and measurement concerns. The findings suggest that EPA's efforts at shifting to a pollution prevention regulatory ethic that holds primacy over pollution control are mixed. Its organizational structure, statutory authority, and incentives system still reflect a single-medium pollution control focus, appropriations for pollution prevention programs and activities are paltry compared to traditional pollution control programs, and participation in the program is voluntary. Yet, the findings also point to some promising programs that are working to institutionalize a pollution prevention regulatory ethic, and many states appear very committed to the concept.KEY WORDS: Pollution prevention; Source reduction; Pollution control; Alternative regulatory design; Barriers to implementation 相似文献