全文获取类型
收费全文 | 16778篇 |
免费 | 158篇 |
国内免费 | 129篇 |
专业分类
安全科学 | 366篇 |
废物处理 | 696篇 |
环保管理 | 1951篇 |
综合类 | 3722篇 |
基础理论 | 3803篇 |
环境理论 | 8篇 |
污染及防治 | 4303篇 |
评价与监测 | 1098篇 |
社会与环境 | 1071篇 |
灾害及防治 | 47篇 |
出版年
2022年 | 142篇 |
2021年 | 146篇 |
2019年 | 116篇 |
2018年 | 227篇 |
2017年 | 224篇 |
2016年 | 356篇 |
2015年 | 270篇 |
2014年 | 416篇 |
2013年 | 1159篇 |
2012年 | 456篇 |
2011年 | 693篇 |
2010年 | 524篇 |
2009年 | 585篇 |
2008年 | 685篇 |
2007年 | 741篇 |
2006年 | 649篇 |
2005年 | 532篇 |
2004年 | 561篇 |
2003年 | 541篇 |
2002年 | 509篇 |
2001年 | 632篇 |
2000年 | 396篇 |
1999年 | 301篇 |
1998年 | 190篇 |
1997年 | 209篇 |
1996年 | 227篇 |
1995年 | 234篇 |
1994年 | 234篇 |
1993年 | 218篇 |
1992年 | 195篇 |
1991年 | 208篇 |
1990年 | 197篇 |
1989年 | 171篇 |
1988年 | 168篇 |
1987年 | 154篇 |
1986年 | 153篇 |
1985年 | 148篇 |
1984年 | 169篇 |
1983年 | 167篇 |
1982年 | 172篇 |
1981年 | 144篇 |
1980年 | 132篇 |
1979年 | 123篇 |
1978年 | 135篇 |
1977年 | 115篇 |
1976年 | 103篇 |
1975年 | 107篇 |
1974年 | 118篇 |
1971年 | 98篇 |
1967年 | 102篇 |
排序方式: 共有10000条查询结果,搜索用时 406 毫秒
471.
David J. Schaeffer Konanur G. Janardan Harold W. Kerster 《Environment international》1980,4(2):157-162
The “filter model” has been developed to explain the biologic effects of radiation and chemicals. We have examined nearly 300 sets of dose response data, of which 50 are presented here. Responses (induced by radiation and chemicals) which have been examined include in vitro survival studies on animal and plant tissues, induction of cellular aberrations and time to tumor or death. Similar data from in vivo studies has also been examined. All of the data appear to fit the model R = a lnD + b(lnD)2 + c, where R is the response, a and b are parameters fitted by regression to a particular set of data, and c is the response at zero (or lowest) dose. By writing this model in exponential form, it can be seen that the response R results from multistage filtering (by net amounts a and b) of the initial dose, D. The threshold is obtained from this model as the point, , at which the second derivative becomes zero. This is given by when a and b are oppositelt signed. 相似文献
472.
473.
Involuntary eye movements in salamanders 总被引:1,自引:0,他引:1
474.
475.
476.
477.
478.
Sadika M. Baladi Catherine M. Lewis Amitava Ganguly Alvin G. Morrow Lisel R. Shoffner Robert F. Blundy Patrick F. Nakagawa Sara T. Mundy Larry Anderson Karen Adams 《补救:环境净化治理成本、技术与工艺杂志》2003,14(1):5-20
Enhanced bioremediation is quickly developing into an economical and viable technology for the remediation of contaminated soils. Until recently, chlorinated organic compounds have proven difficult to bioremediate. Environmentally recalcitrant compounds, such as polychlorinated biphenyls (PCBs) and persistent organic pesticides (POPs) such as dichlorodiphenyl trichloroethane (DDT) have shown to be especially arduous to bioremediate. Recent advances in field‐scale bioremedial applications have indicated that biodegradation of these compounds may be possible. Engineers and scientists at the Savannah River Site (SRS), a major DOE installation near Aiken, South Carolina, are using enhanced bioremediation to remediate soils contaminated with pesticides (DDT and its metabolites, heptachlor epoxide, dieldrin, and endrin) and PCBs. This article reviews the ongoing remediation occurring at the Chemicals, Metals, and Pesticides (CMP) Pits using windrow turners to facilitate microbial degradation of certain pesticides and PCBs. © 2003 Wiley Periodicals, Inc. 相似文献
479.
In the UK for the period 1994-99, a broad range of environmental projects were given financial support through the European Agriculture Guidance and Guarantee Fund under the Objective 1 and Objective 5b programmes. This paper is concerned with the ex-post evaluation of these projects set within a Sustainable Development framework. The aim was to identify project types or characteristics that offered the greatest return on investment. A classification of six broad project types was adopted. The evaluation revealed that there were significant differences between individual projects with respect to the type and scale, and temporal and social distribution of the benefits they delivered. In particular, as well as delivering environmental and economic benefits, many projects made a significant contribution to the development of human and social capital. The paper concludes that it is possible to improve the basis for future project selection in order to maximise the returns on environmental investments in the context of sustainable development. 相似文献
480.
Baxter E. Vieux Fekadu G. Moreda 《Journal of the American Water Resources Association》2003,39(4):757-769
ABSTRACT: A synthetic relationship is developed between nutrient concentrations and discharge rates at two river gauging sites in the Illinois River Basin. Analysis is performed on data collected by the U.S. Geological Survey (USGS) on nutrients in 1990 through 1997 and 1999 and on discharge rates in 1988 through 1997 and 1999. The Illinois River Basin is in western Arkansas and northeastern Oklahoma and is designated as an Oklahoma Scenic River. Consistently high nutrient concentrations in the river and receiving water bodies conflict with recreational water use, leading to intense stakeholder debate on how best to manage water quality. Results show that the majority of annual phosphorus (P) loading is transported by direct runoff, with high concentrations transported by high discharge rates and low concentrations by low discharge rates. A synthetic relationship is derived and used to generate daily phosphorus concentrations, laying the foundation for analysis of annual loading and evaluation of alternative management practices. Total nitrogen (N) concentration does not have as clear a relationship with discharge. Using a simple regression relationship, annual P loadings are estimated as having a root mean squared error (RMSE) of 39.8 t/yr and 31.9 t/yr and mean absolute percentage errors of 19 percent and 28 percent at Watts and Tahlequah, respectively. P is the limiting nutrient over the full range of discharges. Given that the majority of P is derived from Arkansas, management practices that control P would have the most benefit if applied on the Arkansas side of the border. 相似文献