全文获取类型
收费全文 | 772篇 |
免费 | 9篇 |
国内免费 | 13篇 |
专业分类
安全科学 | 37篇 |
废物处理 | 41篇 |
环保管理 | 214篇 |
综合类 | 79篇 |
基础理论 | 161篇 |
污染及防治 | 182篇 |
评价与监测 | 51篇 |
社会与环境 | 28篇 |
灾害及防治 | 1篇 |
出版年
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 10篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 16篇 |
2016年 | 14篇 |
2015年 | 15篇 |
2014年 | 20篇 |
2013年 | 94篇 |
2012年 | 19篇 |
2011年 | 45篇 |
2010年 | 24篇 |
2009年 | 35篇 |
2008年 | 45篇 |
2007年 | 43篇 |
2006年 | 47篇 |
2005年 | 17篇 |
2004年 | 20篇 |
2003年 | 36篇 |
2002年 | 28篇 |
2001年 | 15篇 |
2000年 | 10篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 9篇 |
1996年 | 14篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 8篇 |
1986年 | 8篇 |
1985年 | 9篇 |
1984年 | 15篇 |
1983年 | 14篇 |
1982年 | 13篇 |
1981年 | 18篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1974年 | 7篇 |
1973年 | 3篇 |
1970年 | 3篇 |
排序方式: 共有794条查询结果,搜索用时 526 毫秒
721.
722.
The razorback sucker, Xyrauchen texanus , in the middle Green River (U.S.A.) has been described as a static population consisting of old individuals that will eventually disappear through attrition. Capture data between 1980 and 1992 indicated a constant length frequency despite a slow but positive growth rate of individual fish. Abundance and survival estimates indicated that the population of razorback sucker in the middle Green River is precariously low but dynamic. Although high variation existed among survival estimates, no significant decrease in the population between 1982 and 1992 could be detected. The low level of recruitment occurring in the razorback sucker population of the middle Green River was related to high-flow years, indicating that floodplain habitats may be necessary for survival of the species. 相似文献
723.
724.
Kenneth J. McLean 《Journal of the Air & Waste Management Association (1995)》2013,63(9):866-870
This paper develops an expression for the resistivity of a dust layer which takes into account its particulate nature, dependence of the surface resistivity component on water vapor pressure and temperature, the volume resistivity and the intrinsic properties of the particulate material. A new expression is given for the surface resistivity which, when combined with the equation for volume resistivity, enables the effective resistance of a dust layer to be characterized by five meaningful parameters. These parameters may be determined for a given fly ash sample from a standard set of resistivity curves. Calculated resistivity curves for an industrially produced fly ash are compared with measured curves. 相似文献
725.
Wang-Hsien Ding Herman Valente David Spink Kenneth Aldous David Hilker Steven Connor 《Chemosphere》1989,18(9-10):1935-1942
Total concentrations of PCDDs and PCDFs were predicted from the concentrations of specifically identified dioxin and furan isomers of each congener group by partial least-squares (PLS). The accuracy of this prediction can be used to evaluate results from different data sets or different sources which were calculated by an automatic identification and quantification program-TASQR. 相似文献
726.
727.
Elon S. Verry Jeffrey R. Lewis Kenneth N. Brooks 《Journal of the American Water Resources Association》1983,19(1):59-67
ABSTRACT: Clearcutting aspen from the upland portion of an upland peatland watershed in north central Minnesota caused snowmelt peak discharge to increase 11 to 143 percent. Rainfall peak discharge size increased as much as 250 percent during the first two years after clearcutting, then decreased toward precutting levels in subsequent years. Storm flow volumes from rain during the first two years increased as much as 170 percent but declined to preharvest volumes in the third year. Snowmelt volumes did not significantly change. Snowmelt peak discharge occurred about four to five days earlier after clearcutting, but the timing of storm flow from rainfall was not changed. Snowmelt peaks remained above precut size for nine years after clearcutting on an area undergoing natural regeneration to aspen saplings. Partial cutting - up to approximately one-half of the watershed - reduced peak snowmelt discharge because melt was desynchronized in cleared and forested parts. Clearing more than 2/3 of the watershed caused snowmelt flood peak size to double during years with snow packs in excess of seven inches of water that remained until a day when maximum air temperatures exceeded 60d?F. 相似文献
728.
Kenneth W. Terhune 《Journal of Safety Research》1983,14(1):13-20
This article describes a collision taxonomy that has three main advantages. First, its coding reliability was established; coders independently coding the same cases achieved 96% agreement. Second, it has a hierarchical structure, enabling the user to choose one of three levels of detail; there are 46 collision types at the most detailed level. Third, it captures the role of the individual vehicle, a valuable feature for suggesting the driver problems involved in an accident. The taxonomy was developed after reviewing other systems and incorporates some of their better features. It uses schematic diagrams to facilitate ease of learning and use, and it was developed for use by researchers and for traffic record systems. The value of the taxonomy for suggesting driver problems in accidents was demonstrated with data indicating alcohol impairment and age effects. 相似文献
729.
Frederick A. Kilpatrick Kenneth K Taylor 《Journal of the American Water Resources Association》1986,22(4):537-548
ABSTRACT: The U.S. Geological Survey has performed hundreds of time-of-travel and tracer dispersion studies in streams and estuaries nationwide. This paper presents an approach to unitizing this type of data to make it more universally usable in predicting the behavior of soluble contaminants entering waterways. Practical application of the superposition principle and of the scalene triangle as an approximation of the response curve from a slug injection of a solute are demonstrated to be a means of simulating the downstream effects of any form of soluble contaminant release. 相似文献
730.
Anyone who drinks water or eats fish from the Great Lakes consumes potentially carcinogenic chemicals. In choosing how to respond to such pollution, it is important to put the risks these contaminants pose in perspective. Based on recent measurements of carcinogens in Great Lakes fish and water, calculations of lifetime risks of cancer indicate that consumers of sport fish face cancer risks from Great Lakes contaminants that are several orders of magnitude higher than the risks posed by drinking Great Lakes water. But drinking urban groundwater and breathing urban air may be as hazardous as frequent consumption of sport fish from the Great Lakes. Making such comparisons is difficult because of variation in types and quality of information available and in the methods for estimating risk. Much uncertainty pervades the risk assessment process in such areas as estimating carcinogenic potency and human exposure to contaminants. If risk assessment is to be made more useful, it is important to quantify this uncertainty. 相似文献