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   548篇
  免费   8篇
  国内免费   2篇
教育   383篇
科学研究   73篇
各国文化   2篇
体育   36篇
综合类   1篇
文化理论   6篇
信息传播   57篇
  2022年   6篇
  2021年   6篇
  2020年   14篇
  2019年   15篇
  2018年   21篇
  2017年   22篇
  2016年   22篇
  2015年   11篇
  2014年   21篇
  2013年   90篇
  2012年   7篇
  2011年   16篇
  2010年   8篇
  2009年   7篇
  2008年   9篇
  2007年   7篇
  2006年   7篇
  2005年   8篇
  2004年   10篇
  2003年   9篇
  2002年   8篇
  2001年   12篇
  2000年   6篇
  1999年   9篇
  1998年   8篇
  1996年   8篇
  1994年   8篇
  1993年   4篇
  1992年   10篇
  1991年   7篇
  1990年   8篇
  1989年   10篇
  1988年   7篇
  1987年   4篇
  1986年   9篇
  1985年   10篇
  1984年   7篇
  1983年   8篇
  1980年   8篇
  1978年   14篇
  1976年   8篇
  1974年   8篇
  1973年   4篇
  1972年   4篇
  1969年   4篇
  1968年   3篇
  1967年   3篇
  1965年   4篇
  1961年   3篇
  1947年   3篇
排序方式: 共有558条查询结果,搜索用时 15 毫秒
521.
This paper gives the results of the scientometric analysis of foreign publications by Kazakh authors that was reflected in the SCOPUS DB in 1991–2008. The publication activity is expressed in 3883 documents, the citation index of which is 10 132. The average share of Kazakh publications in the total worldwide flow is equal to 0.017%. The citation rate of publications was revealed to have significantly grown since the 1996–2000 period. It is shown that most articles were written in English and published in periodical editions. The main themes of publications are represented by physics and chemistry. The leading foreign partners of Kazakhstan in the scientific sphere were determined. Kazakh-Russian scientific cooperation is developing most fruitfully.  相似文献   
522.
Urine is a proven source of metabolite biomarkers and has the potential to be a rapid, noninvasive, inexpensive, and efficient diagnostic tool for various human diseases. Despite these advantages, urine is an under-investigated source of biomarkers for multiple sclerosis (MS). The objective was to investigate the level of some urinary metabolites (urea, uric acid and hippuric acid) in patients with MS and correlate their levels to the severity of the disease, MS subtypes and MS treatment. The urine samples were collected from 73 MS patients-48 with RRMS and 25 with SPMS- and age matched 75 healthy controls. The values of urinary urea, uric acid and hippuric acid in MS patients were significantly decreased, and these metabolites in SPMS pattern showed significantly decrease than RRMS pattern. Also showed significant inverse correlation with expanded disability status scale and number of relapses. Accordingly, they may act as a potential urinary biomarkers for MS, and correlate to disease progression.  相似文献   
523.
The purpose of this research was to investigate how lower extremity work was distributed during the pull of cleans performed lifting the barbell to the minimum height required to receive it in a full squat (minimal height clean); or with maximum effort to elevate the barbell as high as possible and receiving it in either a full (maximal effort clean) or partial (power clean) squat. Eight weightlifters screened for proficient technique performed these clean variations at 80% of one repetition maximum. Work performed on the barbell and by the lower extremity net joint moments (NJM) was computed from marker trajectories and ground reaction forces. Total barbell work, lower extremity NJM work, knee extensor work, and knee joint excursion during the second pull was lower in the minimal height clean than the maximal effort and power cleans (P < 0.05). This research demonstrates that more knee extensor work is performed in the second pull of maximal effort and power cleans compared to the minimal height clean. The larger knee extensor work performed is due to larger knee joint excursion during the second pull of the maximal effort and power cleans, but not larger knee extensor NJM.  相似文献   
524.
This paper studies the load mitigation problem for wind turbines by using active tuned mass dampers. A state space model for the tower/nacelle system is established with the consideration of tower/blade interaction. The uncertainties that appear in the damping matrix and natural frequencies are also considered in the controller design. External loads acting on the tower including the drag force induced by winds and the absolute base shear induced by the rotating blades are involved, and shaping filters for online generating these loads are proposed which can be easily implemented in numerical simulations. An adaptive sliding-mode controller is proposed to handle the system uncertainties, external disturbances and hard constraint, and also to improve the overall performance of the wind turbine system. Numerical simulations are performed to demonstrate the effectiveness of the proposed control law.  相似文献   
525.
Landmarks     
Z. M. 《Prospects》1989,19(3):305-309
  相似文献   
526.
The thirsty bird     
Z. Ahmad 《Resonance》1997,2(6):86-88
  相似文献   
527.
528.
The author presents a review of some mathematical aspects of magnetohydrodynamics and plasma-dynamics, and the fields of mathematics required and used in those domains are briefly discussed. The last section is devoted to the discussion of adjusting the mathematical program of a university, from the point of view of engineering, physics and mathematics, so that a greater number of students in those disciplines will be prepared for graduate courses in magnetohydrodynamics and plasma-dynamics.  相似文献   
529.
530.
Landmarks     
Z. M. 《Prospects》1990,20(4):407-409
  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