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   1344篇
  免费   154篇
  国内免费   86篇
安全科学   526篇
废物处理   4篇
环保管理   237篇
综合类   352篇
基础理论   193篇
环境理论   10篇
污染及防治   21篇
评价与监测   26篇
社会与环境   120篇
灾害及防治   95篇
  2024年   5篇
  2023年   20篇
  2022年   45篇
  2021年   56篇
  2020年   60篇
  2019年   66篇
  2018年   40篇
  2017年   85篇
  2016年   87篇
  2015年   59篇
  2014年   48篇
  2013年   78篇
  2012年   106篇
  2011年   102篇
  2010年   70篇
  2009年   73篇
  2008年   56篇
  2007年   86篇
  2006年   56篇
  2005年   56篇
  2004年   46篇
  2003年   38篇
  2002年   25篇
  2001年   28篇
  2000年   34篇
  1999年   24篇
  1998年   20篇
  1997年   15篇
  1996年   11篇
  1995年   19篇
  1994年   11篇
  1993年   4篇
  1992年   12篇
  1991年   6篇
  1990年   3篇
  1989年   7篇
  1988年   2篇
  1987年   3篇
  1985年   1篇
  1984年   1篇
  1983年   2篇
  1982年   2篇
  1981年   3篇
  1980年   1篇
  1978年   4篇
  1977年   1篇
  1975年   1篇
  1973年   1篇
  1972年   1篇
  1971年   3篇
排序方式: 共有1584条查询结果,搜索用时 484 毫秒
991.
三种生产论:可持续发展的基本理论   总被引:44,自引:15,他引:29  
本文通过研究人与环境的辩证关系,提出了物质生产、人的生产和环境生产是可持续发展系统的基本模型,分析了三种生产之间的和谐关系,并对深化环境影响评价、开展环境建设、建立新伙伴关系等问题进行了探讨。  相似文献   
992.
本在对絮凝理论分析的基础上,设计了几种不同扰流形式的旋流扰流絮凝反应器。通过试验对其絮凝效果进行了分析和比较,找出了比较合理的絮凝器结构。这对于研制开发新型絮凝反应器,发挥新型絮凝剂的效能,提高出水水质,保证供水安全具有十分重要的现实意义。  相似文献   
993.
本文运用可持续发展的“三种生产”理论,对我国北方荒漠化地区的人地系统进行了解析,指出人口生产的膨胀、物质生产的低效率和环境生产的萎缩,以及由此造成的三种生产系统之间支撑与制约机制的破坏,是导致我国北方荒漠化不断扩展的根本原因。  相似文献   
994.
Reintroductions are important components of conservation and recovery programs for rare plant species, but their long-term success rates are poorly understood. Previous reviews of plant reintroductions focused on short-term (e.g., ≤3 years) survival and flowering of founder individuals rather than on benchmarks of intergenerational persistence, such as seedling recruitment. However, short-term metrics may obscure outcomes because the unique demographic properties of reintroductions, including small size and unstable stage structure, could create lags in population growth. We used time-to-event analysis on a database of unusually well-monitored and long-term (4–28 years) reintroductions of 27 rare plant species to test whether life-history traits and population characteristics of reintroductions create time-lagged responses in seedling recruitment (i.e., recruitment time lags [RTLs]), an important benchmark of success and indicator of persistence in reintroduced populations. Recruitment time lags were highly variable among reintroductions, ranging from <1 to 17 years after installation. Recruitment patterns matched predictions from life-history theory with short-lived species (fast species) exhibiting consistently shorter and less variable RTLs than long-lived species (slow species). Long RTLs occurred in long-lived herbs, especially in grasslands, whereas short RTLs occurred in short-lived subtropical woody plants and annual herbs. Across plant life histories, as reproductive adult abundance increased, RTLs decreased. Highly variable RTLs were observed in species with multiple reintroduction events, suggesting local processes are just as important as life-history strategy in determining reintroduction outcomes. Time lags in restoration outcomes highlight the need to scale success benchmarks in reintroduction monitoring programs with plant life-history strategies and the unique demographic properties of restored populations. Drawing conclusions on the long-term success of plant reintroduction programs is premature given that demographic processes in species with slow life-histories take decades to unfold.  相似文献   
995.
Conflict caused by wild herbivores damaging crops is an almost universal problem in conservation. We designed and implemented a game-theory-based system for supporting farmers whose crops were being heavily damaged by wild herbivores. In this community-operated system, farmers self-report their production, which is endorsed by neighboring farmers. The average deficit in production is compensated for by a payment that is directly proportional to the average deficit in production of the group and to the individual farmer's productivity. As a result, farmers are compensated for the average damage (support) and rewarded for individual productivity (reward) (i.e., support cum reward [SuR]). The design of the game is such that only honest reporting gives maximum returns. Farmers who underreport receive less payment because the SuR amount is proportionate to their self-reported productivity. The endorsing farmers, in their own self-interest, prevent overreporting. The system involves multiple game situations, the combined result of which is a stable strategy based on honesty and hard work. In 2 villages along the western boundary of Tadoba Andhari Tiger Reserve in central India, we tested the system with 75 farmers over 6 crop seasons. After a few initial attempts to cheat, honesty prevailed throughout the group. Average crop productivity increased 2.5-fold, in spite of damage, owing to increased effort by farmers. Apart from wildlife conflict resolution, the model offers a promising alternative to crop insurance and a potential behavioral green revolution in agriculture.  相似文献   
996.
Compensating farmers out of public funds for financiallosses due to adverse weather conditions and animaldiseases is fairly common in most Western countries.This government policy differs from that towardsentrepeneurs in other economic branches. Whatjustifies this differential treatment? In the firstpart of this article, three theories of justice arepresented that offer a general framework for dealingwith problems of compensatory justice. In the secondpart, the possibilities of justifiying differentialtreatment of agriculture within each of these theoriesare explored. It is concluded that compensatorypractices in agriculture require fundamentalrethinking in view of the changing technological,economic, and cultural conditions of agriculture.  相似文献   
997.
以“四湖”地区典型湖垸(新兴垸)为背景,给出了典型湖垸水利系统满足综合设计排涝标准的评价准则。用大系统理论与方法,建立了该湖垸水利规划的大系统数学模型,提出了根据子系统之间的关联变量修建节制闸的设计思想,从而使排涝灌溉一体化。最后,用动态规划方法,给出了递推关系式。  相似文献   
998.
生态全息论对发展循环经济的启示   总被引:6,自引:0,他引:6  
作者根据生态全息的理论,提出了推行工业生态系统和循环经济的具体步骤。发展循环经济是一个大的系统工程,涉及到经济、环境、社会的各个层面,涉及到国民经济的各个行业和企业,必须进行系统的研究和战略部署,理念不能作为目标,没有政府的支持和企业的积极参与是不行的。  相似文献   
999.
资源环境生态经济价值综论   总被引:1,自引:0,他引:1  
本文在回顾经济学资源环境观的基础上 ,系统分析了资源环境生态经济价值的内涵 ;并进一步对生态学、环境经济学与可持续发展等相关研究进行分析和总结。  相似文献   
1000.
在对镇江古运河2009~2013年的降雨量、降雨径流污染物量监测的基础上,运用回归分析建立降雨量-径流污染方程,并采用灰色理论对未来降雨量进行预测,进而得出降雨径流面源污染年负荷值。结果表明:2014~2020年间,镇江古运河降雨径流中污染物TP、NH3-N和SS的年负荷与降雨量同向变化,2020年降雨量达到1 381.2 mm时,污染物TP、NH3-N和SS的年负荷可分别达到217.15 t、421.4 t、5 811.87 t,数值较大;灰色理论与回归分析结合所提出的降雨径流面源污染年负荷预测方法,能够在小样本、贫信息和波动数据序列情况下,简捷有效的对降雨径流面源污染负荷进行高精度的预测,实用与推广价值较大。  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