全文获取类型
收费全文 | 17477篇 |
免费 | 282篇 |
国内免费 | 380篇 |
专业分类
安全科学 | 613篇 |
废物处理 | 737篇 |
环保管理 | 2591篇 |
综合类 | 2970篇 |
基础理论 | 4482篇 |
环境理论 | 7篇 |
污染及防治 | 4607篇 |
评价与监测 | 991篇 |
社会与环境 | 1016篇 |
灾害及防治 | 125篇 |
出版年
2023年 | 95篇 |
2022年 | 171篇 |
2021年 | 168篇 |
2020年 | 189篇 |
2019年 | 151篇 |
2018年 | 284篇 |
2017年 | 268篇 |
2016年 | 412篇 |
2015年 | 334篇 |
2014年 | 445篇 |
2013年 | 1408篇 |
2012年 | 614篇 |
2011年 | 885篇 |
2010年 | 669篇 |
2009年 | 759篇 |
2008年 | 824篇 |
2007年 | 868篇 |
2006年 | 716篇 |
2005年 | 603篇 |
2004年 | 621篇 |
2003年 | 563篇 |
2002年 | 536篇 |
2001年 | 642篇 |
2000年 | 519篇 |
1999年 | 315篇 |
1998年 | 209篇 |
1997年 | 228篇 |
1996年 | 221篇 |
1995年 | 266篇 |
1994年 | 209篇 |
1993年 | 208篇 |
1992年 | 174篇 |
1991年 | 182篇 |
1990年 | 178篇 |
1989年 | 180篇 |
1988年 | 153篇 |
1987年 | 133篇 |
1986年 | 156篇 |
1985年 | 143篇 |
1984年 | 190篇 |
1983年 | 147篇 |
1982年 | 171篇 |
1981年 | 157篇 |
1980年 | 130篇 |
1979年 | 149篇 |
1978年 | 94篇 |
1977年 | 98篇 |
1975年 | 88篇 |
1974年 | 93篇 |
1972年 | 96篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
921.
This review describes the more important features of the emission, chemistry, transport and deposition of pollutants involved in acid deposition. Global emissions, both natural and man-made, of sulphur and nitrogen oxides are discussed and examples of spatial distributions and trends over the last century presented. The more significant chemical and physical processes involved in the transformation of the primary emissions into their acidic end products are described, including a summary of the approximate timescales of the processes involved. Measurements and modelled calculations of spatial and temporal patterns in the deposition of acidic pollutants by both wet and dry pathways are presented. 相似文献
922.
923.
924.
925.
926.
Albin Brandstetter Roger L. Engel Dennis B. Cearlock 《Journal of the American Water Resources Association》1973,9(6):1188-1200
ABSTRACT: A comprehensive mathematical model (Urban Wastewater Management Model) has been developed to continuously simulate time-varying wastewater flows and qualities in complex metropolitan combined sewerage systems. The model serves three functions: (1) assessment of existing or planned system performance in relation to other wastewater discharges in either a metropolitan or river basin area; (2) determination of the optium operation or automatic control of existing or planned systems during rainstorms; and (3) determination of the most economically feasible combination of design alternatives for improving or expanding existing systems to meet specified performance criteria. The model provides an efficient engineering tool for evaluating and controlling pollutant discharges from combined sewerage systems (including treatment plants) to receiving waters, while considering the time and spacial variations of rainfall and dry-weather flows and qualities as well as economic constraints. 相似文献
927.
928.
929.
The southern pine beetle, Dendroctonus frontalis Zimmermann, is a major insect pest of pines in the southern U.S.A. A population dynamic model of D. frontalis within an infestation was developed. The model is based on the integration of several component submodels that describe individual life stage processes of the beetle. The inclusion of variable forest stand density and microclimate conditions results in a model response which closely follows actual field responses. A sensitivity analysis was performed to investigate effects of weather conditions and the importance of the spatial patterns within the forest. 相似文献
930.