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   114篇
  免费   0篇
财政金融   13篇
工业经济   6篇
计划管理   19篇
经济学   16篇
贸易经济   4篇
经济概况   2篇
水利工程   54篇
  2014年   1篇
  2012年   9篇
  2011年   10篇
  2010年   1篇
  2008年   1篇
  2006年   5篇
  2005年   2篇
  2004年   1篇
  2003年   1篇
  2002年   3篇
  2001年   3篇
  2000年   1篇
  1999年   4篇
  1998年   7篇
  1997年   2篇
  1996年   3篇
  1995年   3篇
  1994年   3篇
  1993年   4篇
  1992年   6篇
  1991年   13篇
  1990年   6篇
  1989年   7篇
  1988年   3篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   4篇
  1983年   2篇
  1982年   2篇
  1980年   1篇
  1979年   2篇
  1975年   1篇
排序方式: 共有114条查询结果,搜索用时 0 毫秒
1.
2.
The paper expresses an attempt to tackle the problem due to the presence of micropollutants in wastewater which may be able to disrupt the endocrine system of some organisms. These kinds of compounds are ubiquitously present in municipal wastewater treatment plant (WWTP) effluents. The aim of this paper is to compare the fate of the alkylphenols-APs (4-(tert-octyl)) phenol, t-nonylphenol and 4-p-nonylphenol and the hormones (estrone, 17β-estradiol and 17α-ethinylestradiol) in a submerged anaerobic membrane bioreactor (SAMBR) pilot plant and in a conventional activated sludge wastewater treatment plant (CTP). The obtained results are also compared with the results obtained in a previous study carried out in an aerobic MBR pilot plant. The results showed that the APs soluble concentrations in the SAMBR effluent were always significantly higher than the CTP ones. Moreover, the analyses of the suspended fraction revealed that the AP concentrations in the SAMBR reactor were usually higher than in the CTP reactor, indicating that under anaerobic conditions the APs were accumulated in the digested sludge. The aerobic conditions maintained both in the CTP system and in the aerobic MBR favoured the APs and hormones degradation, and gave rise to lower concentrations in the effluent and in the reactor of these systems. Furthermore, the results also indicated that the degradation of APs under aerobic conditions was enhanced working at high solid retention time (SRT) and hydraulic retention time (HRT) values.  相似文献   
3.
A new electron beam-based approach for the direct functionalization of polyethersulfone, polyvinylidene fluoride, polysulfone as well as polyacrylonitrile membranes in a one-step procedure is presented. Aqueous solutions of functional molecules were immobilized on the membrane surface by electron beam treatment. The resulting membranes show significantly increased flux and water wettability accompanied by decreased protein adsorption. Stability tests demonstrated the permanence of the modification. This new method neither requires any preceding surface functionalization nor the use of catalysts/photoinitiators or other toxic reagents. In addition, it avoids the synthesis of hydrophilic monomers/polymers, thus avoiding additional synthetic and purification steps as well as the use of organic solvents.  相似文献   
4.
5.
6.
7.
This article analyzes some of the major factors affecting the content and process of training paraprofessionals in state-run psychiatric hospitals. It reflects on the challenge of providing the relevant knowledge and skills for staff members with limited or no clinical experience yet who are expected to provide the highest quality of care in a rapidly changing field. The author uses her own experience at the only state-run psychiatric hospital in Delaware to present ideas of how to create a learning environment for paraprofessionals that could be transferred to similar facilities.  相似文献   
8.
9.
10.
"A theoretical model of rural-urban migration has been developed with special reference to the informal sector. The wage rate and employment in the informal sector are determined endogenously. The paper shows the simultaneous existence of open unemployment and informal sector in the urban area in migration equilibrium. The effects of alternative subsidy policies on unemployment and welfare of the workers are studied." The model is intended primarily for use in analyzing trends and policies in developing countries.  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