全文获取类型
收费全文 | 203篇 |
免费 | 7篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 13篇 |
废物处理 | 18篇 |
环保管理 | 30篇 |
综合类 | 23篇 |
基础理论 | 50篇 |
污染及防治 | 50篇 |
评价与监测 | 13篇 |
社会与环境 | 15篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 18篇 |
2015年 | 5篇 |
2014年 | 12篇 |
2013年 | 15篇 |
2012年 | 14篇 |
2011年 | 14篇 |
2010年 | 6篇 |
2009年 | 5篇 |
2008年 | 9篇 |
2007年 | 12篇 |
2006年 | 9篇 |
2005年 | 7篇 |
2004年 | 5篇 |
2003年 | 8篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1974年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有213条查询结果,搜索用时 15 毫秒
191.
We documented the spawning patterns of the leopard grouper, Mycteroperca rosacea, from April to June 2005 in the central Gulf of California, Mexico to draw comparisons with other aggregate-spawning groupers
and provide information useful for management of their fishery. Adults formed spawning aggregations of 150 to >700 individuals
at specific sites, and spawning occurred daily at these sites from late April through early June. Courtship occurred throughout
the day, but spawning was restricted to the evening hours. Adults spawned in groups of 6–40 fish, and pair-spawning was not
observed. The group-spawning behavior of adults and the gonosomatic indices of mature males (maximum = 7.2%) suggest that
sperm competition was present. The site-specificity of leopard grouper spawning aggregations and diel spawning period were
typical of most aggregating groupers, and the size and structure of these aggregations was similar to other species in the
genus Mycteroperca. Leopard grouper behavior patterns were unusual in that spawning aggregations persisted for extended periods, spawning was
not synchronized with the lunar cycle, and adults aggregated during non-spawning periods. The extensive duration and site-specificity
of spawning aggregations and the propensity of M. rosacea to form aggregations year-round increases the vulnerability of the species to overfishing. Policies that limit harvest from
these aggregations are needed to improve the management of leopard grouper fisheries in the Gulf of California. 相似文献
192.
The discriminant validity of perceptions of organizational politics, organizational support, and procedural and distributive justice was examined as the distinctions between these variables have been blurred in past research. Results from a sample of 418 full‐time employees provided evidence of discriminant validity for these variables. First, structural equation modelling was used to isolate the best structural representation of these four variables. Then, six theoretically relevant predictors (i.e., leader–member exchange, centralization, formalization, co‐worker cooperation, role conflict, and locus of control) were examined in an effort to provide further conceptual separation. Five of the six antecedents distinguished among politics, justice, and support. Suggestions for additional research that can shed light on the distinctions and similarities of these variables are offered based on the results of this study. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
193.
Monteil MA 《Environmental geochemistry and health》2008,30(4):339-343
Dust clouds travel across the Atlantic to the Americas and the Caribbean Islands. This long-range transport of dust leads to clouds that are enriched with small particles less than 10 microm aerodynamic diameter (PM10) which can reach human airways. The dust clouds also bring pollen, microbes, insects and chemicals, all of which could potentially have a negative impact on human health. This has led to a small number of retrospective studies being conducted on the islands of Barbados and Trinidad to look at possible associations between dust cover and acute asthma admissions to Emergency Rooms. The results have been conflicting. This review examines these studies, offers possible explanations for the differences in results, and suggests that there is a need for a prospective Caribbean-wide study to assess fully any relationship between African dust clouds and human respiratory and cardiovascular diseases. 相似文献
194.
We tested the hypothesis that species loss at one trophic level will reduce the temporal stability of populations at other trophic levels. We examined the temporal stability of annual plant populations on plots that experimentally manipulated the functional diversity of seed-eating rodent consumers. Experimental reduction of rodent functional diversity destabilized populations of small-seeded plants but had less consistent effects on larger-seeded species. Small-seeded species also exhibited a greater number of years of zero abundance. Thus, experimental reduction of rodent functional diversity resulted in lower plant diversity. The decline in the temporal stability of small-seeded plants likely resulted from increased interspecific competition by large-seeded plants. These results demonstrate that the loss of species at one trophic level can lead to reduced richness at lower trophic levels via competition and reduced temporal stability. 相似文献
195.
196.
How urbanization unfolds in the text few decades and which urban development path we choose are potentially critical to the efforts aimed at stabilizing greenhouse gas emissions. However, our understanding of urban, as a unit or system, and its cross-scale linkages in the context of carbon management is at infancy state. In this context, this article outlines, the key challenges and introduces a new scientific initiative - Urban and Regional Carbon Management Initiative of the Global Carbon Project, which has raised key scientific questions with the aim to find reasonable answers. This article mainly showcases key science questions, past activities and future outlook with the aim to reach out to the related scientific and policy communities. 相似文献
197.
Ronald J. Scrudato Jeffrey R. Chiarenzelli James J. Pagano Michele Wunderlich 《补救:环境净化治理成本、技术与工艺杂志》1999,9(2):7-21
Through volatilization and long distance atmospheric transport, polychlorinated biphenyls (PCBs) have been redistributed throughout the global environment. Over the last 70 years, these compounds have permeated every known environmental niche including the remote polar regions of the globe. In this article, the solubility and volatility of the PCB congeners are reviewed relative to the remedial technologies that are currently in use or under consideration. The following discussion focuses primarily on the management options for PCB-contaminated, subaqueous solids that require removal, dewatering, drying, and other treatment to degrade the target contaminants and/or containment in engineered facilities including constructed islands, upland secure landfills and subaqueous pits. Environmental mobility resulting from natural and engineered processes is discussed in relation to the potential for contributing to the global loading and redistribution of PCBs. Additionally, select emerging technologies and management options are reviewed relative to their potential to produce secondary environmental impacts resulting from the soluble and/or volatile redistribution of PCBs. Based on a lack of long-term experience and the recognition that contaminants will remain unaltered for decades, technologies involving engineered containment structures should be considered temporary remedial measures until cost-competitive, destructive processing of contaminated sediments is feasible. 相似文献
198.
199.
Environmental Fluid Mechanics - In this work, a summary of Leonardo da Vinci’s contribution in the field of fluid mechanics is reported. Some theoretical laws or fluid flows analyzed or drawn... 相似文献
200.
Electrochemical peroxidation (ECP) is a proprietary process that utilizes sacrificial iron electrodes and stochiometrically balanced applications of hydrogen peroxide to efficiently destroy aqueous phase contaminants. In laboratory trials it has been successful in reducing, often to non‐detectable levels, BTEX, fuel additives, chlorinated solvents, and polychlorinated biphenyls in ground waters. The process has also been found effective in reducing the chemical and biological oxygen demand of industrial waste water. Agency‐approved pilot tests will be conducted at two gasoline spill sites during 2000 where traditional pump and treat methods have proven ineffectual because of ground water chemistry or subsurface hydrologic conditions. The ECP process utilizes a tripartite treatment strategy consisting of 1) ex situ chemical oxidation; 2) in situ oxidation by reinjection of treated water with residual oxidants at the head of the plume; and 3) reestablishment of aerobic biodegradation by alteration of subsurface redox conditions. In contrast to other in situ oxidation treatment methods, dissolved iron is derived electrochemically, negating the need for ferrous salt addition. Dilute hydrogen peroxide (3 percent) is incrementally added to maximize oxidation efficiency and eliminate safety and environmental concerns accompanying the use of highly concentrated solutions. Results of laboratory trials and the geological and geochemical considerations of upcoming pilot‐scale applications are presented. Other potential applications currently under investigation include combination with other remedial processes (e.g. permeable barriers and hydrogen release compounds) to insure complete and rapid contaminant mineralization. 相似文献