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   281篇
  免费   15篇
  国内免费   5篇
安全科学   12篇
废物处理   4篇
环保管理   68篇
综合类   35篇
基础理论   86篇
污染及防治   58篇
评价与监测   23篇
社会与环境   10篇
灾害及防治   5篇
  2023年   5篇
  2022年   9篇
  2021年   4篇
  2020年   2篇
  2019年   8篇
  2018年   13篇
  2017年   12篇
  2016年   18篇
  2015年   14篇
  2014年   7篇
  2013年   16篇
  2012年   17篇
  2011年   18篇
  2010年   8篇
  2009年   12篇
  2008年   13篇
  2007年   20篇
  2006年   15篇
  2005年   13篇
  2004年   5篇
  2003年   7篇
  2002年   11篇
  2001年   10篇
  2000年   8篇
  1999年   3篇
  1998年   1篇
  1997年   4篇
  1996年   1篇
  1994年   3篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   2篇
  1987年   2篇
  1986年   1篇
  1984年   2篇
  1983年   1篇
  1981年   1篇
  1980年   2篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1971年   1篇
  1966年   1篇
  1963年   1篇
  1934年   1篇
排序方式: 共有301条查询结果,搜索用时 10 毫秒
181.
A number of studies have examined emotional and belief responses following a disaster, yet there has been limited comparative analysis of responses to disasters in different places. This paper reviews the results of 366 questionnaires that evaluated key emotional and belief concepts in Haiti after the earthquake on 12 January 2010 (n=212) and in Indonesia after the earthquake in Yogyakarta on 27 May 2006 (n=154). The results indicate significant differences between the responses in the two settings, particularly in relation to feelings of impunity, self‐blame for the disaster, regret about pre‐earthquake behaviour, and a sense of justice in the world. Furthermore, the impacts of age, education, and gender on responses also were different in the two case study sites. Overall, the results suggest that understanding the cultural, religious, and social contexts of different disaster locales is important in comprehending the emotions and beliefs that manifest themselves in the wake of a major disaster.  相似文献   
182.
Among group-living organisms, some individuals initiate groups by being the first to attack a prey item or the first to colonize a new settlement site. In the group-living mountain pine beetle (Dendroctonus ponderosae), first attackers (known as pioneers) on live trees suffer higher mortality due to tree defenses than do beetles that join aggregations. This study examined factors that affect an individual’s propensity to initiate an aggregation. When placed on an unoccupied tree, the probability of successfully entering the tree was positively correlated with body condition (residual of mass versus length regression). However, beetles in better condition took longer to initiate tunnel construction than those in poorer condition, suggesting that pioneering is a “desperation” strategy used when low energy reserves preclude further dispersal or when potential trees are rare. These contrasting patterns suggest pioneering is a nonlinear behavioral response, such that beetles with the smallest energy reserves and beetles with the greatest energy reserves both avoid pioneering. We further found that pioneering was more likely when the environment favored success, such as in smaller diameter trees (which may have weaker defenses) and earlier in the season (when the probability of recruiting conspecifics is higher). Our results suggest that pioneers incorporate both internal and external variables in their decision to attack an uncolonized tree.  相似文献   
183.
There is concern that elevated levels of selenium found in the source water of a newly formed wetland park in Las Vegas, Nevada, may have detrimental effects on local wildlife. In this study, we collected and analyzed water samples monthly for a three year period from the inflow and outflow of the system. We also gathered dominant aquatic plants and selected terrestrial plants and analyzed the water and plant tissues (root, shoot, leaf and flower) for selenium by high resolution Inductively Coupled Plasma Mass Spectrometer. Except for storm events and the introduction of an alternative low selenium content source water during summer low-flow conditions, selenium in the water was relatively stable. The concentration in the outflow tended to be slightly lower than the inflow. Concentrations of selenium in the dominant plant taxa in this wetlands were typical of ecosystems in the western United States and varied by taxa, tissue type, localized conditions (e.g., contact with selenium-laden water), and to a lesser extent, seasons. Selenium in the aquatic plant spiny naiad (Najas marina) was relatively high and may pose an ecological risk to wildlife during the late spring and summer. Additional work is underway investigating aquatic food chain accumulations of selenium as well as mass balance of selenium in the system.  相似文献   
184.
Faith-based organizations (FBOs) have played a significant role in environment-related forms of development and governance in Melanesia, including the Solomon Islands. Yet despite their centrality, there remain significant gaps in understandings of processes and outcomes associated with FBO engagement in environment-related development interventions. This paper addresses this gap by analysing the place of the Christian Fellowship Church (CFC), an indigenous FBO active in plantation forestry (and other activities) in the Western Province in the Solomon Islands. We find that the CFC possesses impressive income-generating potential and political networks; however this does not always translate into positive social, economic or environmental outcomes at the village level. While FBOs such as CFC are often championed as playing an important role in environmental governance in an under-resourced nation state, the reality is that they can fall well short in delivering appropriate outcomes for poor communities or the environment despite, and because of, their close ties to target communities.  相似文献   
185.
186.
Muths E  Scherer RD  Corn PS  Lambert BA 《Ecology》2006,87(4):1048-1056
Male boreal toads (Bufo boreas) are thought to return to the breeding site every year but, if absent in a particular year, will be more likely to return the following year. Using Pollock's robust design we estimated temporary emigration (the probability a male toad is absent from a breeding site in a given year) at three locations in Colorado, USA: two in Rocky Mountain National Park and one in Chaffee County. We present data that suggest that not all male toads return to the breeding site every year. Our analyses indicate that temporary emigration varies by site and time (for example, from 1992 to 1998, the probability of temporary emigration ranged from 10% to 29% and from 3% to 95% at Lost Lake and Kettle Tarn, respectively). Although the results provide weak evidence that males are more likely to return after a year's hiatus, a general pattern of state-dependent temporary emigration was not supported. We also hypothesized relationships between temporary emigration and a number of weather variables. While some competitive models included weather covariates, imprecise and variable estimates of the effects of these covariates precluded fully defining their impact on temporary emigration.  相似文献   
187.
Preference rankings for 13 macrophytes were established for the subtidal herbivorous snail Lithopoma undosum using two-choice laboratory experiments and consumption rates. L. undosum did not discriminate among three kelp foods (Egregia menziesii, Eisenia arborea and Macrocystis pyrifera) but ate kelp preferentially and more rapidly over all but Ulva spp. among tested macrophytes. Secondary preferences were established for the red alga Pterocladiella capillacea, followed by the coralline Lithothrix aspergillum, whereas the brown seaweeds Zonaria farlowii and Halidrys dioica and the seagrass Phyllospadix torreyi were the least preferred macrophytes. Fastest consumption rates (1.91 g day−1) were measured in trials consisting only of kelp foods. These results indicate that L. undosum exhibits clear feeding preferences even when given less-preferred, non-kelp macrophytes. Using an ash-marker technique, we determined total organic, carbon, and nitrogen assimilation efficiencies (AE%) for six macroalgae used in preference trials. Tested macrophytes were assimilated at different efficiencies but a pattern was not detected between AE (%) and a macrophyte’s position in L. undosum’s preference hierarchy. Highest total organic AEs were found for P. capillacea (61.2%) and H. dioica (59.4%); lowest AEs were detected for E. menziesii (34.9%), a preferred dietary item. Nitrogen was assimilated from red algae with higher efficiencies (74.9–84.3%) than from brown or green algae. These data suggest that the digestive capabilities of L. undosum are better suited for assimilating organic material and nitrogen from less-preferred, non-kelp foods. This supports the hypothesis that factors besides nutritional composition and digestive optimization have played a role in the evolution of feeding preferences in L. undosum and probably other herbivorous snails associated with northeastern Pacific kelp beds.  相似文献   
188.
In this daily diary study, we investigated the within‐person relationship between daily illegitimate tasks and next‐day counterproductive work behavior (CWB). We explored a moderated mediation model where the link between illegitimate tasks and CWB is mediated by daily end‐of‐work anger, with daily time pressure moderating the relationship between illegitimate tasks and end‐of‐work anger. We collected data from 114 full‐time employees across 10 consecutive working days. Results showed that within individuals, daily illegitimate tasks positively predicted next‐day CWB, and the relationship was mediated by daily end‐of‐work anger. Further, daily time pressure moderated the relationship between daily illegitimate tasks and daily end‐of‐work anger with the relationship being stronger when daily time pressure was high.  相似文献   
189.
A study was conducted to evaluate the association between PCBs in residential indoor air and in the serum of older, long time residents of three upper Hudson River communities. Samples of indoor air and of serum were collected from 170 persons 55 to 74 years of age, and analyzed for PCBs using glass capillary gas chromatography. After adjusting for age, BMI, cigarette smoking, and Hudson River fish consumption with multiple linear regression analysis, the results indicated statistically significant associations between concentrations in indoor air and serum for PCB-28, a lightly chlorinated congener common in air that accumulates in serum, and PCB-105. Duration of exposure was an important factor, since among persons who had lived in their home for 39 years or more, 11 of the 12 most commonly detected congeners were significantly correlated, as was their sum (∑ PCB). Significant associations between indoor air and serum PCB concentrations also were more likely when collected in cooler months and if the two samples were collected within 20 d of each other. The study is among the first to indicate that PCB concentrations characteristic of residential indoor air are associated with a detectable increase in body burden.  相似文献   
190.
Air-soil exchange is an important process governing the fate of polycyclic aromatic hydrocarbons (PAHs). A novel passive air sampler was designed and tested for measuring the vertical concentration profile of 4 low molecular weight PAHs in gaseous phase (PAHLMW4) in near soil surface air. Air at various heights from 5 to 520 mm above the ground was sampled by polyurethane foam disks held in down-faced cartridges. The samplers were tested at three sites: A: an extremely contaminated site, B: a site near A, and C: a background site on a university campus. Vertical concentration gradients were revealed for PAHLMW4 within a thin layer close to soil surface at the three sites. PAH concentrations either decreased (Site A) or increased (Sites B and C) with height, suggesting either deposition to or evaporation from soils. The sampler is a useful tool for investigating air-soil exchange of gaseous phase semi-volatile organic chemicals.  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