全文获取类型
收费全文 | 312篇 |
免费 | 4篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 25篇 |
废物处理 | 18篇 |
环保管理 | 84篇 |
综合类 | 28篇 |
基础理论 | 66篇 |
污染及防治 | 70篇 |
评价与监测 | 7篇 |
社会与环境 | 19篇 |
灾害及防治 | 2篇 |
出版年
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 6篇 |
2016年 | 2篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 33篇 |
2012年 | 11篇 |
2011年 | 18篇 |
2010年 | 9篇 |
2009年 | 13篇 |
2008年 | 8篇 |
2007年 | 14篇 |
2006年 | 19篇 |
2005年 | 12篇 |
2004年 | 15篇 |
2003年 | 11篇 |
2002年 | 8篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 7篇 |
1985年 | 4篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 2篇 |
1979年 | 6篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1972年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1962年 | 1篇 |
1952年 | 1篇 |
排序方式: 共有319条查询结果,搜索用时 250 毫秒
111.
112.
Fred E. Hahn 《Die Naturwissenschaften》1977,64(12):632-632
113.
B. P. Ushakov 《Marine Biology》1968,1(3):153-160
A survey of literature is given with respect to two problems: (1) resistance temperature adaptation in protozoans and multicellular animals at early stages of ontogenesis (cellular adaptations), and (2) changes in thermostability of somatic cells related to temperature adaptations of multicellular organisms. The following aspects are considered and discussed in detail: changes in resistance of protozoans to cold and heat, their causes and genetic controls; possible mechanisms of changes in thermostability of gametes, zygotes and multicellular organisms at oligolcellular stages of development; mechanisms of heat injury to cells; types of changes in heat-resistance of somatic cells from multi-cellular animals during individual life and during phylogenesis. The object of the review is to emphasize those aspects of temperature resistance adaptation of animals which have scarcely been investigated. 相似文献
114.
Learning and adaptation in the management of waterfowl harvests 总被引:1,自引:0,他引:1
Johnson FA 《Journal of environmental management》2011,92(5):1385-1394
A formal framework for the adaptive management of waterfowl harvests was adopted by the U.S. Fish and Wildlife Service in 1995. The process admits competing models of waterfowl population dynamics and harvest impacts, and relies on model averaging to compute optimal strategies for regulating harvest. Model weights, reflecting the relative ability of the alternative models to predict changes in population size, are used in the model averaging and are updated each year based on a comparison of model predictions and observations of population size. Since its inception the adaptive harvest program has focused principally on mallards (Anas platyrhynchos), which constitute a large portion of the U.S. waterfowl harvest. Four competing models, derived from a combination of two survival and two reproductive hypotheses, were originally assigned equal weights. In the last year of available information (2007), model weights favored the weakly density-dependent reproductive hypothesis over the strongly density-dependent one, and the additive mortality hypothesis over the compensatory one. The change in model weights led to a more conservative harvesting policy than what was in effect in the early years of the program. Adaptive harvest management has been successful in many ways, but nonetheless has exposed the difficulties in defining management objectives, in predicting and regulating harvests, and in coping with the tradeoffs inherent in managing multiple waterfowl stocks exposed to a common harvest. The key challenge now facing managers is whether adaptive harvest management as an institution can be sufficiently adaptive, and whether the knowledge and experience gained from the process can be reflected in higher-level policy decisions. 相似文献
115.
Sexual selection is often characterized by polygynous breeding systems, size dimorphism, and skewed operational sex ratios.
Koalas are sexually dimorphic in multiple domains, yet are absent from the literature on sexual selection and the structure
of their mating system is unclear. We provide the first documentation of the strength of sexual selection in koalas by using
microsatellite markers to identify sires. We combine the genetic data with morphological data in order to assess the role
of body size in regulating reproductive output. During our 4-year study, 37% of males were identified as possible sires. Males
were significantly larger than females, with sires heavier than non-sires. Male body mass correlated with annual reproductive
output, with Crow’s Index of Opportunity for Selection revealing that variation in male reproductive success was threefold
higher than that of females. Since it appears that male koalas rarely engage in physical confrontations over access to females,
size dimorphism could be based upon non-agonistic competition and/or female mate choice. We propose that size dimorphism in
koalas evolved as a consequence of endurance rivalry promoting vocal sexual advertisements that attract females. We suggest
that female choice is a key mediator of male reproductive output. 相似文献
116.
117.
Since the early 1990s the U.S. government has been developing and implementing public policies that advance the redevelopment of brownfields, and the recent passage of the Small Business Liability Relief and Brownfields Revitalization Act (SBLRBRA) will significantly advance efforts to integrate environmental contamination mitigation and redevelopment. Experience has demonstrated that successful redevelopment requires the collection, analysis, and interpretation of environmental data in a timely and cost‐effective manner in order to allow developers and lenders to efficiently use cleanup resources, develop response strategies that integrate cleanup with redevelopment, and support meaningful outreach to involved stakeholders. Recent advances in the science and technology of site characterization hold the promise of improved site characterization outcomes while saving time and money. One such advancement, the Triad Approach, combines systematic up‐front planning with the use of a dynamic field investigation process and the generation of real time data to allow in‐field decision making on sample location selection. This article describes an application of the Triad Approach to redevelopment of an urban greenway in Trenton, New Jersey. The Triad Approach, initiated through a partnership between the City of Trenton, New Jersey Department of Environmental Protection, New Jersey Institute of Technology, and the U.S. Environmental Protection Agency, demonstrated that this approach could accelerate the characterization of the 60‐acre, 11‐parcel project area. Environmental issues that were solved using the Triad Approach included the delineation of the extent of historic fill, determination of no further action for several areas of concern, detailed investigation of specific impacted areas and the acquisition of sufficient data to allow the city to make important decisions regarding remediation costs and property acquisition. © 2003 Wiley Periodicals, Inc. 相似文献
118.
Fred Luthans James B. Avey Bruce J. Avolio Steven M. Norman Gwendolyn M. Combs 《组织行为杂志》2006,27(3):387-393
After first providing the meaning of psychological capital (PsyCap), we present a micro‐intervention to develop it. Drawn from hope, optimism, efficacy, and resiliency development, this PsyCap Intervention (PCI) is shown to have preliminary support for not only increasing participants' PsyCap, but also financial impact and high return on investment. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
119.
120.