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   26175篇
  免费   675篇
  国内免费   2113篇
安全科学   1018篇
废物处理   1261篇
环保管理   2870篇
综合类   6344篇
基础理论   6218篇
环境理论   5篇
污染及防治   7029篇
评价与监测   2013篇
社会与环境   1888篇
灾害及防治   317篇
  2023年   222篇
  2022年   583篇
  2021年   566篇
  2020年   492篇
  2019年   460篇
  2018年   597篇
  2017年   651篇
  2016年   843篇
  2015年   741篇
  2014年   1030篇
  2013年   2282篇
  2012年   1160篇
  2011年   1344篇
  2010年   1184篇
  2009年   1156篇
  2008年   1297篇
  2007年   1265篇
  2006年   1181篇
  2005年   921篇
  2004年   900篇
  2003年   900篇
  2002年   854篇
  2001年   1059篇
  2000年   791篇
  1999年   493篇
  1998年   381篇
  1997年   326篇
  1996年   361篇
  1995年   317篇
  1994年   300篇
  1993年   278篇
  1992年   276篇
  1991年   228篇
  1990年   232篇
  1989年   231篇
  1988年   208篇
  1987年   158篇
  1986年   134篇
  1985年   139篇
  1984年   174篇
  1983年   154篇
  1982年   200篇
  1981年   136篇
  1980年   119篇
  1979年   153篇
  1978年   124篇
  1977年   108篇
  1976年   100篇
  1975年   84篇
  1974年   88篇
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
1.
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   
2.
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   
3.
Huang  Ying  Jiang  Qiongji  Yu  Xubiao  Gan  Huihui  Zhu  Xia  Fan  Siyi  Su  Yan  Xu  Zhirui  He  Cunrui 《Environmental science and pollution research international》2021,28(37):51251-51264
Environmental Science and Pollution Research - Trace copper ion (Cu(II)) in water and wastewater can trigger peroxymonosulfate (PMS) activation to oxidize organic compounds, but it only works under...  相似文献   
4.
The Science of Nature - We present the first study that compares phenological variation in parasite load and inflammatory response in a lizard with asynchronous male and female gonadal cycles....  相似文献   
5.
The study addresses the potential of using concentrated solar power plants (CSPs) as a sustainable alternative of clean energy generation in the Mediterranean region and, in particular, in its North Africa shore. This location presents attractive conditions for the installation of CSPs, in particular high solar irradiation, good manpower concentration, and proximity and availability of water resources for condenser cooling. Energetic, exergetic, and economic analyses were conducted taking into consideration a particular type of CSPs - the parabolic trough concentrated solar power plant, which incorporates the most proven technology and it is already used in Southern Europe (Spain). In addition, the study considered the impact of project financing and incentives on the cost of energy. The combination of higher values for performance and potentially lower levelized cost of electricity (LCE) for the North Africa Mediterranean Rim than the South of Spain region can yield a very favorable return for the invested capital. Tripoli compared to Almeria presented superior performance and potentially lower LCE values ($0.18/kWh versus $0.22/kWh). This is significant, even when it is taken into consideration the fact that the plant in Tripoli, despite a relatively modest capacity factor of 34%, has a large gross power output of 173,886 MWhe. In addition, the implementation at the Tripoli location of a plant similar to the Anadsol plant has a slight advantage (2–3%) in terms of overall efficiency.  相似文献   
6.
7.
8.
ABSTRACT

In this study, a three-dimension (3D) computational model was proposed to investigate the flow and heat transfer characteristics of the intake grilles of two different fuel cell vehicles. The models of the intake grilles were constructed according to the actual sizes of two vehicles, namely, Roewe 950 and Toyota Mirai, considering the heat dissipation unit to simplify the heat transfer model of the vehicle. The results showed that relative to Roewe 950, Mirai intake air flow rate was approximately 10% higher, the heat transfer capacity was approximately 7% higher, and the intake grille area was larger. The coolant outlet temperature of Mirai was lower than that of Roewe 950, which was beneficial for the long term and stable operation of a fuel cell. This comparative study provided guidance for the intake grille and radiator design of fuel cell vehicles. The only difference between fuel cell vehicles on the market and conventional vehicles was that in the former, the internal combustion engine was replaced with a fuel cell stack, which had insufficient heat transfer capacity because of the reducing temperature difference. Increasing the intake grille area and the heat exchange capacity of the radiator were the key issues for the development of fuel cell vehicles. In this study, an optimal window opening angle of the radiator fin of 23° provided a maximal heat transfer coefficient.  相似文献   
9.
Research suggests that encouraging motivated residents to reach out to others in their social network is an effective strategy for increasing the scale and speed of conservation action adoption. However, little is known about how to effectively encourage large numbers of residents to reach out to others about conservation causes. We examined the influence of normative and efficacy-based messaging at motivating residents to engage in and to encourage others to participate in native plant gardening in their community. To do so, we conducted a field experiment with messages on mailings and tracked native plant vouchers used. Efficacy messages tended to be more effective than normative messages at increasing residents’ willingness to reach out to others to encourage conservation action, as indicated by a several percentage point increase in native plant voucher use by residents’ friends and neighbors. Messages sometimes had different impacts on residents based on past behaviors and perceptions related to native plant gardening. Among these subgroups, efficacy and combined efficacy and norm messages most effectively encouraged individual and collective actions, as indicated by increased voucher usage. Our findings suggest that interventions that build residents’ efficacy for engaging in a conservation behavior and for reaching out to others may be a promising path forward for outreach. However, given our results were significant at a false discovery rate cutoff of 0.25 but not 0.05, more experimental trials are needed to determine the robustness of these trends.  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