全文获取类型
收费全文 | 11546篇 |
免费 | 82篇 |
国内免费 | 90篇 |
专业分类
安全科学 | 295篇 |
废物处理 | 508篇 |
环保管理 | 1480篇 |
综合类 | 2504篇 |
基础理论 | 2589篇 |
环境理论 | 5篇 |
污染及防治 | 3014篇 |
评价与监测 | 695篇 |
社会与环境 | 572篇 |
灾害及防治 | 56篇 |
出版年
2022年 | 91篇 |
2021年 | 100篇 |
2019年 | 73篇 |
2018年 | 156篇 |
2017年 | 137篇 |
2016年 | 226篇 |
2015年 | 174篇 |
2014年 | 245篇 |
2013年 | 843篇 |
2012年 | 312篇 |
2011年 | 434篇 |
2010年 | 347篇 |
2009年 | 402篇 |
2008年 | 444篇 |
2007年 | 501篇 |
2006年 | 442篇 |
2005年 | 367篇 |
2004年 | 370篇 |
2003年 | 380篇 |
2002年 | 342篇 |
2001年 | 431篇 |
2000年 | 314篇 |
1999年 | 210篇 |
1998年 | 115篇 |
1997年 | 123篇 |
1996年 | 109篇 |
1995年 | 156篇 |
1994年 | 150篇 |
1993年 | 127篇 |
1992年 | 130篇 |
1991年 | 151篇 |
1990年 | 121篇 |
1989年 | 128篇 |
1988年 | 133篇 |
1987年 | 118篇 |
1986年 | 85篇 |
1985年 | 102篇 |
1984年 | 127篇 |
1983年 | 126篇 |
1982年 | 125篇 |
1981年 | 99篇 |
1980年 | 95篇 |
1979年 | 110篇 |
1978年 | 91篇 |
1977年 | 86篇 |
1976年 | 78篇 |
1975年 | 90篇 |
1974年 | 103篇 |
1973年 | 70篇 |
1965年 | 75篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
971.
Rosanna L. Mattingly Edwin E. Herricks Douglas M. Johnston 《Environmental management》1993,17(6):781-795
The environmental impact of loss of natural stream and riparian habitat is of concern throughout the United States and Europe.
Environmental impacts related to such activities as channelization of and levee construction along streams and rivers are
particularly apparent in the Midwestern United States. The objective of the research presented here was to delineate the extent,
relative degree of impact, and implications for management of channelization and levee construction along watercourses located
in the state of Illinois. According to records maintained through the Illinois Streams Information System data base (Illinois
Department of Conservation), nearly 25% of surface water resources in the state have been modified directly by channelization
and/or levee construction. Reviews of agency records, elaboration of case histories, interviews with agency personnel, and
inspections of impacted sites indicated that these alterations have occurred without the benefit of effective mitigation.
Although permit records may provide suggestions for mitigation to be incorporated in the design of a particular project, permits
issued generally do not require even minimal instream habitat and bank stabilization efforts in conjunction with channel alteration.
Information derived from policy and case study analyses suggests that institutional constraints, rather than lack of particular
understanding about mitigation, provide major barriers to protecting the state's surface water resources in terms of regulatory
review, policy interpretation and implementation, and project evaluation. Recommendations for environmental management efforts
regarding these and similar channel alterations are elaborated from these findings. 相似文献
972.
Over the last several years, the inhalation of decay products coming from radon-222 has become a national health concern.
It is estimated that somewhere between 16,000 and 20,000 people die annually in the United States from lung cancer due to
exposure to these decay products. Nationwide, 95% of all homes have not been tested for radon, and so it would seem that any
methodology that could give a general idea of indoor radon concentrations (without actually testing the house itself) might
be useful. While not intended to replace a radon test, which is both simple and inexpensive, our project attempts to predict
indoor radon concentrations based on easily obtainable information from Soil Conservation Service county soil surveys and
US Geological Survey surficial geology maps. We have chosen four parameters: soil permeability, surficial geology, soil shrink-swell
potential, and distance to the nearest geologic fault. Of these four variables, surficial geology and distance to fault correlated
well to winter indoor radon concentrations as measured by short-term (48-h) tests. While it is understood that there are limits
to this methodology, primarily because of map scale problems, the correlations mentioned above were very strong and suggest
further study would be useful. 相似文献
973.
John F. Potter 《The Environmentalist》1993,13(3):161-163
974.
Robert N. Havis Carlos V. Alonso John G. King Russell F. Thurow 《Journal of the American Water Resources Association》1993,29(3):435-444
ABSTRACT: A simulation model [Salmonid Spawning Analysis Model (SSAM)] was developed as a management tool to evaluate the relative impacts of stream sediment load and water temperature on salmonid egg survival. The model is useful for estimating acceptable sediment loads to spawning habitat that may result from upland development, such as logging and agriculture. Software in common use in the USA were adapted for use in gravel bedded rivers and linked to simulate water temperature (the USFWS Instream Water Temperature, SNTEMP model) and water and sediment routing (the USAE Scour and Deposition in Rivers and Reservoirs, HEC-6 model, version 3.2). These models drive the redd (spawning nest) model (the USDA-ABS Sediment Intrusion Dissolved Oxygen SIDO model) which simulates sediment intrusion and dissolved oxygen concentration in the redd environment. The SSAM model predictions of dissolved oxygen and water temperature compared favorably with field data from artificial redds containing hatchery chinook salmon eggs. 相似文献
975.
976.
977.
ABSTRACT. In 1970, the Canadian Federal Government passed the Canada Water Act which provides for a co-operative federal-provincial approach to water resource management. The purpose of this paper is to outline our definition of comprehensive planning and the approach being taken under the new legislation. Two basic premises underly the definition. They are that resource management consists of an array of problems and that the prime function of planning is to provide information for decision making. The definition of comprehensive planning is embodied in a general statement and a set of principles. The principles define the approach that should be taken to provide adequate information for decision making in today's complex environment. A brief resume of the jurisdictions for water management in Canada leads to a discussion of a joint federal-provincial comprehensive study of the Qu'Appelle River Basin in Southern Saskatchewan. The basin and the study are described briefly. This is followed by an outline of the economic and social considerations which are being incorporated into the comprehensive planning study for the basin. 相似文献
978.
Roy Burke James P. Heaney Edwin E. Pyatt 《Journal of the American Water Resources Association》1973,9(3):433-447
ABSTRACT The problem of water resources management can be viewed as one requiring the existence and application of some type of “collective decision” mechanism. Currently, the general water resource decision problem is solved using an “individual decision” format without explicit consideration of the dominant social decision system. This paper demonstrates the need for blending technical planning activities with organized societal processes and then proposes a specific public decision framework to satisfy this requirement. The key element in this planning framework is a generalized “bargaining arena” which serves to link technical activities with the social system. Using this bargaining device we can (1) specify policy at a local level, (2) incorporate “social decision” rules into the planning process, and (3) provide local access to the decision process. A simple case of regional water quality management is used to describe the application of this planning procedure and to offer encouragement for successful use in more complex real-world cases. 相似文献
979.
980.
The hydrocarbons contents (n-alkanes, polycyclic aromatic hydrocarbons) were determined in the sea urchin Arbacia lixula. Multivariate data analysis as principal component analysis, factor analysis and, cluster analysis were applied to elucidate sources of pollution. PCA and FA were performed to establish the relationships between variables (hydrocarbons), samples (sea urchin) and sources of pollution. 相似文献