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   39669篇
  免费   329篇
  国内免费   222篇
安全科学   847篇
废物处理   1863篇
环保管理   5261篇
综合类   5586篇
基础理论   11639篇
环境理论   21篇
污染及防治   9428篇
评价与监测   2752篇
社会与环境   2629篇
灾害及防治   194篇
  2022年   181篇
  2021年   197篇
  2019年   226篇
  2018年   1882篇
  2017年   1764篇
  2016年   1725篇
  2015年   618篇
  2014年   704篇
  2013年   2167篇
  2012年   1323篇
  2011年   2562篇
  2010年   1808篇
  2009年   1659篇
  2008年   2176篇
  2007年   2598篇
  2006年   1189篇
  2005年   1101篇
  2004年   1051篇
  2003年   1058篇
  2002年   1093篇
  2001年   1259篇
  2000年   872篇
  1999年   553篇
  1998年   444篇
  1997年   435篇
  1996年   443篇
  1995年   484篇
  1994年   440篇
  1993年   397篇
  1992年   414篇
  1991年   374篇
  1990年   377篇
  1989年   411篇
  1988年   349篇
  1987年   300篇
  1986年   278篇
  1985年   305篇
  1984年   300篇
  1983年   328篇
  1982年   323篇
  1981年   271篇
  1980年   243篇
  1979年   269篇
  1978年   229篇
  1977年   195篇
  1976年   201篇
  1975年   192篇
  1974年   172篇
  1973年   171篇
  1972年   199篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
12.
The purpose of the research is to identify the critical challenges that are impeding the adoption of e-mobility in India. It also aims to give a roadmap how to address these challenges while taking into considerations concerns of all the relevant stakeholders. Based on an in-depth literature review, an exploratory research design is employed to delve deep into various aspects of e-mobility. This is followed by a three-phase Delphi technique to identify and rate the e-mobility challenges in the Indian context. The study successfully identifies four different categories of challenges and proposes integrative framework for e-mobility. Further, the research goes on to lay out the future roadmap for mass adoption of electric vehicles (EVs) in India. The research is novel in terms of presenting a holistic viewpoint on e-mobility in India. Its originality lies in identifying the major inhibitors obstructing EVs adoption in India and then suggesting the roadmap how to overcome these impediments for mass adoption of e-mobility.  相似文献   
13.
14.
Journal of Material Cycles and Waste Management - The traditional Chinese medicinal plant Magnolia officinalis has a wide range of applications; including more than 200 kinds of patented Chinese...  相似文献   
15.
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   
16.
17.
18.
19.
20.
ABSTRACT: The use of nonparametric tests for monotonic trend has flourished in recent years to support routine water quality data analyses. The validity of an assumption of independent, identically distributed error terms is an important concern in selecting the appropriate nonparametric test, as is the presence of missing values. Decision rules are needed for choosing between alternative tests and for deciding whether and how to pre-process data before trend testing. Several data pre-processing procedures in conjunction with the Mann-Kendall tau and the Seasonal Kendall test (with and without serial correlation correction) are evaluated using synthetic time series with generated serial correlation and missing data. A composite test (pre-testing for serial correlation followed by one of two trend tests) is evaluated and was found to perform satisfactorily.  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