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   88965篇
  免费   1222篇
  国内免费   1086篇
安全科学   3711篇
废物处理   3222篇
环保管理   13683篇
综合类   21118篇
基础理论   26134篇
环境理论   72篇
污染及防治   13950篇
评价与监测   5329篇
社会与环境   3539篇
灾害及防治   515篇
  2022年   792篇
  2021年   803篇
  2020年   647篇
  2019年   859篇
  2018年   1123篇
  2017年   1148篇
  2016年   2147篇
  2015年   1828篇
  2014年   2586篇
  2013年   9242篇
  2012年   2124篇
  2011年   2312篇
  2010年   3239篇
  2009年   3348篇
  2008年   1818篇
  2007年   1636篇
  2006年   2146篇
  2005年   2170篇
  2004年   2471篇
  2003年   2325篇
  2002年   1866篇
  2001年   2206篇
  2000年   1927篇
  1999年   1515篇
  1998年   1369篇
  1997年   1356篇
  1996年   1472篇
  1995年   1563篇
  1994年   1474篇
  1993年   1308篇
  1992年   1313篇
  1991年   1279篇
  1990年   1231篇
  1989年   1196篇
  1988年   1047篇
  1987年   968篇
  1986年   995篇
  1985年   1062篇
  1984年   1153篇
  1983年   1163篇
  1982年   1171篇
  1981年   1088篇
  1980年   941篇
  1979年   918篇
  1978年   816篇
  1977年   707篇
  1976年   636篇
  1975年   599篇
  1973年   624篇
  1972年   621篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Russian Journal of Ecology - The dynamics of the species richness, breeding density, and structure of the community of birds occupying nest-boxes upon a 50-fold reduction of atmospheric emissions...  相似文献   
2.
Environmental Science and Pollution Research - Legacy (i.e., polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD)) and alternative halogenated flame retardants (HFRs) were...  相似文献   
3.
Environmental Science and Pollution Research - A current environmental problem is the uncontrolled use of various pesticides that are harmful to the environment and public health. The herbicide...  相似文献   
4.
This article postulates strong endogenous relationships in lower income countries between institutional quality, financial development and sustained economic growth. These associations were investigated using the vector-error correction model (VECM) and Granger causality method for a sample of 79 countries from 2005 to 2022. The findings show that (1) these variables reinforce each other in the short run. (2) In the long run, both institutional quality and financial development can fuel economic growth. (3) The positive effect of institutional quality on economic growth is greater than that of financial development. Policy implications of these findings are that careful attention should be paid to co-development policies to enhance the institutional quality and the financial system in these economies. Policies should also consider economic growth strategies to enable sustainable economic growth rates.  相似文献   
5.
Russian Journal of Ecology - In this paper, Ellenberg’s indicator values were estimated in order to soil nitrogen (N), pH (R) and soil moisture (M) in different subalpine grassland...  相似文献   
6.
Environmental Science and Pollution Research - Nutrient source and transport study in tropical creeks adjacent to megacities are sparse on a regional and global scale. High-frequency chemical data...  相似文献   
7.
Catalytic activity of spinel ferrite in breaking down toxic dye materials are promising due to their uniqueness. In this study, aluminum-doped copper zinc ferrite, Cu0.4Zn0.6-xAlxFe2O4 (x = 0.0, 0.2, 0.4, 0.6), a catalyst for toxic dye degradation is synthesized through chemical co-precipitation route. The formation of the spinel ferrite catalyst is initially confirmed by Fourier transform infrared spectra, which shows the frequency of metal-oxygen bond vibration at 539 and 427 cm−1 attributed to the tetrahedral and octahedral sites respectively. Higher intensity sharp peak of X-ray diffraction for (311) plane is the evidence for the phase purity and the formation of spinel ferrite. The crystallite size is found to decrease with the increase of Al3+ ion. The surface structure of the obtained particles is investigated using a scanning electron microscope. Analyses of the material's magnetic characteristics using a vibrating sample magnetometer (VSM) revealed that it is, in fact, a soft magnet, as evidenced by the loop of its hysteresis, which is narrow. The catalytic degradation of methylene blue dye under the mechanism of the photo-Fenton process is studied with the obtained spinel ferrites and the result is found to be as high as 96.5%. The process follows pseudo-second order kinetics and the Langmuir isotherm.  相似文献   
8.
Russian Journal of Ecology - A new method for assessing the response of biota to climatic changes in the ecosystem has been tested. In the Central Forest Natural Biosphere Reserve, the average...  相似文献   
9.
Effective management refers to the ability of a protected area or indigenous territory to meet its objectives, particularly as they relate to the protection of biodiversity and forest cover. Effective management is achieved through a process of consolidation, which among other things requires legally protecting sites, integrating sites into land‐use planning, developing and implementing management and resource‐use plans, and securing long‐term funding to pay for recurrent costs. Effectively managing all protected areas and indigenous territories in the Amazon may be needed to avoid a deforestation tipping point beyond which regional climatic feedbacks and global climate change interact to catalyze irreversible drying and savannization of large areas. At present, protected areas and indigenous territories cover 45.5% (3.55 million km2) of the Amazon, most of the 60–70% forest cover required to maintain hydrologic and climatic function. Three independent evaluations of a long‐term large‐scale philanthropic initiative in the Amazon yielded insights into the challenges and advances toward achieving effective management of protected areas and indigenous territories. Over the life of the initiative, management of sites has improved considerably, particularly with respect to management planning and capacity building, but few sites are effectively managed and many lack sufficient long‐term financing, adequate governance, support of nongovernmental organizations, and the means to withstand economic pressures. The time and money required to complete consolidation is still poorly understood, but it is clear that philanthropic funding is critical so long as essential funding needs are not met by governments and other sources, which could be on the order of decades. Despite challenges, it is encouraging that legal protection has expanded greatly and management of sites is improving steadily. Management of protected areas in other developing countries could be informed by improvements that have occurred in Amazonian countries.  相似文献   
10.
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