首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   33410篇
  免费   397篇
  国内免费   313篇
安全科学   1177篇
废物处理   1570篇
环保管理   4997篇
综合类   4793篇
基础理论   8540篇
环境理论   12篇
污染及防治   8237篇
评价与监测   2385篇
社会与环境   2183篇
灾害及防治   226篇
  2023年   149篇
  2022年   275篇
  2021年   356篇
  2020年   221篇
  2019年   292篇
  2018年   484篇
  2017年   527篇
  2016年   794篇
  2015年   609篇
  2014年   931篇
  2013年   2888篇
  2012年   1155篇
  2011年   1533篇
  2010年   1250篇
  2009年   1291篇
  2008年   1602篇
  2007年   1530篇
  2006年   1382篇
  2005年   1202篇
  2004年   1175篇
  2003年   1132篇
  2002年   1064篇
  2001年   1151篇
  2000年   859篇
  1999年   563篇
  1998年   424篇
  1997年   436篇
  1996年   450篇
  1995年   521篇
  1994年   444篇
  1993年   397篇
  1992年   434篇
  1991年   391篇
  1990年   364篇
  1989年   359篇
  1988年   318篇
  1987年   270篇
  1986年   284篇
  1985年   282篇
  1984年   302篇
  1983年   295篇
  1982年   300篇
  1981年   272篇
  1980年   207篇
  1979年   200篇
  1978年   183篇
  1977年   146篇
  1975年   149篇
  1973年   174篇
  1972年   146篇
排序方式: 共有10000条查询结果,搜索用时 515 毫秒
871.
Environmental Science and Pollution Research - Resident physicians are the first-line health service providers, subjected to prolonged working hours, sleep deprivation and high job demands. Work...  相似文献   
872.
Conventional wastewater treatments are not efficient in removing parabens, which may thus end up in surface waters, posing a threat to aquatic biota and hu  相似文献   
873.
874.
875.
The growing industrial interest in adopting sustainability programmes has ushered in studies regarding sustainability indicators which have continually flourished in current literature. However, limited attention is given to the development of priority ranking, which is an important input for any adopting firm. This paper presents a hybrid multi-criteria approach in determining priority areas in sustainable manufacturing (SM). Using fuzzy analytic hierarchy process to address uncertainty in hierarchical decision-making, this paper determines SM priority strategies and eventually identifies even lower level strategies. The computed sustainable manufacturing index is presented at both the organizational and operational levels for a real case study of an industrial plastic manufacturing firm. This work provides a detailed and transparent hierarchical decision-making approach based on SM framework, the use of which could be valuable to practicing managers across industries in their pursuit of greater sustainability.  相似文献   
876.
877.
Despite many studies showing that landscape corridors increase dispersal and species richness for disparate taxa, concerns persist that corridors can have unintended negative effects. In particular, some of the same mechanisms that underlie positive effects of corridors on species of conservation interest may also increase the spread and impact of antagonistic species (e.g., predators and pathogens), foster negative effects of edges, increase invasion by exotic species, increase the spread of unwanted disturbances such as fire, or increase population synchrony and thus reduce persistence. We conducted a literature review and meta‐analysis to evaluate the prevalence of each of these negative effects. We found no evidence that corridors increase unwanted disturbance or non‐native species invasion; however, these have not been well‐studied concerns (1 and 6 studies, respectively). Other effects of corridors were more often studied and yielded inconsistent results; mean effect sizes were indistinguishable from zero. The effect of edges on abundances of target species was as likely to be positive as negative. Corridors were as likely to have no effect on antagonists or population synchrony as they were to increase those negative effects. We found 3 deficiencies in the literature. First, despite studies on how corridors affect predators, there are few studies of related consequences for prey population size and persistence. Second, properly designed studies of negative corridor effects are needed in natural corridors at scales larger than those achievable in experimental systems. Third, studies are needed to test more targeted hypotheses about when corridor‐mediated effects on invasive species or disturbance may be negative for species of management concern. Overall, we found no overarching support for concerns that construction and maintenance of habitat corridors may result in unintended negative consequences. Negative edge effects may be mitigated by widening corridors or softening edges between corridors and the matrix. Other negative effects are relatively small and manageable compared with the large positive effects of facilitating dispersal and increasing diversity of native species. Efectos Negativos Potenciales de los Corredores  相似文献   
878.
The effect of applied compression on the nature of liquid flow and hence the movement of contaminants within municipal solid waste was examined by means of thirteen tracer tests conducted on five separate waste samples. The conservative nature of bromide, lithium and deuterium tracers was evaluated and linked to the presence of degradation in the sample. Lithium and deuterium tracers were non-conservative in the presence of degradation, whereas the bromide remained effectively conservative under all conditions. Solute diffusion times into and out of less mobile blocks of waste were compared for each test under the assumption of dominantly dual-porosity flow. Despite the fact that hydraulic conductivity changed strongly with applied stress, the block diffusion times were found to be much less sensitive to compression. A simple conceptual model, whereby flow is dominated by sub-parallel low permeability obstructions which define predominantly horizontally aligned less mobile zones, is able to explain this result. Compression tends to narrow the gap between the obstructions, but not significantly alter the horizontal length scale. Irrespective of knowledge of the true flow pattern, these results show that simple models of solute flushing from landfill which do not include depth dependent changes in solute transport parameters are justified.  相似文献   
879.
Since the first product became commercially available in 1995, biotechnology has become the fastest growing crop technology, dominating large shares of the global agricultural market. The development of biotechnology, however, has given rise to questions regarding human and ecological safety, culminating in local and global political battles. While researchers interested in biotech politics have focused on areas such as media framing, social movements, and campaign work, less attention has been paid to how the industry has historically promoted and legitimized this swift proliferation. In this study, we conduct a discourse analysis of documents available on live and archived websites to discern the legitimation strategies employed by one important corporate actor, Monsanto. Findings show that for nearly two decades, Monsanto consistently employed discursive resources that concealed details about actors and action, reflected trends among experts in global sustainability discourse, and reshaped narratives to promote itself, products, and biotechnology in general.  相似文献   
880.
Ornamental horticulture has been identified as an important threat to plant biodiversity and is a major pathway for plant invasions worldwide. In this context, the family Cactaceae is particularly challenging because it is considered the fifth most threatened large taxonomic group in the world; several species are among the most widespread and damaging invasive species; and Cactaceae is one of the most popular horticultural plant groups. Based on the Convention on International Trade in Endangered Species of Wild Flora and Fauna and the 11 largest online auction sites selling cacti, we documented the international cactus trade. To provide an in‐depth look at the dynamics of the industry, we surveyed the businesses involved in the cactus trade in South Africa (a hotspot of cactus trade and invasions). We purchased seeds of every available species and used DNA barcoding to identify species to the genus level. Although <20% of this trade involved threatened species and <3% involved known invasive species, many species were identified by a common name. However, only 0.02% of the globally traded cacti were collected from wild populations. Despite a large commercial network, all South African imports (of which 15% and 1.5% were of species listed as threatened and invasive, respectively) came from the same source. With DNA barcoding, we identified 24% of the species to genus level. Based on our results, we believe that if trade restrictions are placed on the small proportion of cacti that are invasive and there is no major increase in harvesting of native populations, then the commercial trade in cactus poses a negligible environmental threat. However, there are currently no effective methods for easily identifying which cacti are traded, and both the illicit harvesting of cacti from the wild and the informal trade in invasive taxa pose on‐going conservation challenges.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号