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   95925篇
  免费   1236篇
  国内免费   1164篇
安全科学   3810篇
废物处理   3523篇
环保管理   14574篇
综合类   21336篇
基础理论   27045篇
环境理论   75篇
污染及防治   17347篇
评价与监测   5782篇
社会与环境   4224篇
灾害及防治   609篇
  2022年   834篇
  2021年   850篇
  2020年   670篇
  2019年   889篇
  2018年   1263篇
  2017年   1281篇
  2016年   2279篇
  2015年   1848篇
  2014年   2607篇
  2013年   9299篇
  2012年   2405篇
  2011年   2836篇
  2010年   3405篇
  2009年   3499篇
  2008年   2455篇
  2007年   2390篇
  2006年   2674篇
  2005年   2518篇
  2004年   2858篇
  2003年   2680篇
  2002年   2246篇
  2001年   2740篇
  2000年   2222篇
  1999年   1595篇
  1998年   1401篇
  1997年   1392篇
  1996年   1519篇
  1995年   1616篇
  1994年   1507篇
  1993年   1367篇
  1992年   1376篇
  1991年   1334篇
  1990年   1286篇
  1989年   1235篇
  1988年   1093篇
  1987年   1020篇
  1986年   1000篇
  1985年   1073篇
  1984年   1174篇
  1983年   1182篇
  1982年   1186篇
  1981年   1103篇
  1980年   952篇
  1979年   942篇
  1978年   834篇
  1977年   728篇
  1976年   646篇
  1974年   625篇
  1973年   663篇
  1972年   662篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Catastrophic disasters like earthquake and flood cause widespread destruction and financial devastation. This has brought disaster management into limelight making it a burgeoning academic research field. The remarkable rise of ICT (Information and Communication Technology) has instigated the scientific world to incorporate these technologies in disaster management. This study presents scientometric analysis to identify the status quo of research on the management of various disasters and role of ICT in it. This paper uses bibliographic data retrieved from Scopus for the observation period from 2011 to 2018. We provide extensive insights into growth of publications, citation pattern and their connectedness with other subject disciplines. Furthermore, we identify most productive and influential countries, institutes and journals. Our study analyses co-occurrence of keywords using Visualization of Similarities (VOS) Viewer. This structured overview will enhance the understanding of this field leading to more focussed and purposeful research.  相似文献   
42.
Journal of Material Cycles and Waste Management - The present research work focused on fabricating Biodegradable Plate (BD plate) composed of rice husk ash, bagasse and corn starch which is...  相似文献   
43.
44.
Quantitative methods have been applied to the study of floristic structure and diversity in Samarskaya Luka. The results show that Samarskaya Luka is a floristically heterogeneous area in which six elementary floras can be distinguished. This area has been assessed as a floristically autonomous formation, and its floristic representativeness was estimated.  相似文献   
45.
46.
Abstract:  Introduction of artificial light into wildlife habitat represents a rapidly expanding form of human encroachment, particularly in coastal systems. Light pollution alters the behavior of sea turtles during nesting; therefore, long-wavelength lights—low-pressure sodium vapor and bug lights—that minimize impacts on turtles are required for beach lighting in Florida (U.S.A.). We investigated the effects of these two kinds of lights on the foraging behavior of Santa Rosa beach mice (  Peromyscus polionotus leucocephalus ). We compared patch use and giving-up densities of mice for experimental food patches established along a gradient of artificial light in the field. Mice exploited fewer food patches near both types of artificial light than in areas with little light and harvested fewer seeds within patches near bug lights. Our results show that artificial light affects the behavior of terrestrial species in coastal areas and that light pollution deserves greater consideration in conservation planning.  相似文献   
47.
Introduced and cryptogenic species in Port Phillip Bay, Victoria, Australia   总被引:4,自引:0,他引:4  
Port Phillip Bay (PPB) is a large (1,930 km2), temperate embayment in southern Victoria, Australia. Extensive bay-wide surveys of PPB have occurred since 1840. In 1995/1996 the Commonwealth Scientific and Industrial Research Organization (CSIRO) Centre for Research on Introduced Marine Pests (CRIMP) undertook an intensive evaluation of the region with the aims of developing a comprehensive species list of native and introduced biota and contrasting previous bay-wide assessments with a current field survey in order to detect new incursions and discern alterations to native communities. Two methods were used to meet these aims: a re-evaluation of regional museum collections and published research in PPB to identify and determine the timing of introductions; and field surveys for benthic (infauna, epifauna and encrusting) organisms between September 1995 to March 1996. One hundred and sixty introduced (99) and cryptogenic (61) species were identified representing over 13% of the recorded species of PPB. As expected, the majority of these are concentrated around the shipping ports of Geelong and Melbourne. Invasions within PPB appear to be increasing, possibly due to an increase in modern shipping traffic and an increase in aquaculture (historically associated with incidental introductions); however the records of extensive biological surveys suggest that this may, in part, be an artefact of sampling effort. In contrast to Northern Hemisphere studies, PPB (and Southern Hemisphere introductions in general) have significantly different suites of successfully invading taxa. PPB is presented as one of the most invaded marine ecosystems in the Southern Hemisphere.Communicated by M.S. Johnson, Crawley  相似文献   
48.
During the artificial reproduction of salmonides, the fecundity can be increased either by improving the viability of spermatozoa, or by extending the time period during which a roe micropile remains open, thus allowing its fecundation. Practically, this can be achieved by the use of some fertilising techniques suitable for fish species. Here, we show that the reproduction of rainbow trout in a 1:1 solution of deuterium-depleted water and distilled water led to a significant increase in survival of roes during their embryonic development. Moreover, the addition of glucose and fructose into the deuterium-depleted fertilising solutions led to a further increase in roe survival during embryonic development. The increase in survival is mainly explained by an increase in the motility of spermatozoa.  相似文献   
49.
50.
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