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   23191篇
  免费   1391篇
各国政治   1158篇
工人农民   997篇
世界政治   1766篇
外交国际关系   911篇
法律   14555篇
中国共产党   2篇
中国政治   139篇
政治理论   4874篇
综合类   180篇
  2023年   102篇
  2021年   111篇
  2020年   500篇
  2019年   545篇
  2018年   695篇
  2017年   729篇
  2016年   823篇
  2015年   607篇
  2014年   680篇
  2013年   2778篇
  2012年   635篇
  2011年   681篇
  2010年   658篇
  2009年   684篇
  2008年   693篇
  2007年   754篇
  2006年   711篇
  2005年   603篇
  2004年   626篇
  2003年   529篇
  2002年   576篇
  2001年   776篇
  2000年   724篇
  1999年   575篇
  1998年   361篇
  1997年   270篇
  1996年   299篇
  1995年   268篇
  1994年   248篇
  1993年   261篇
  1992年   374篇
  1991年   404篇
  1990年   376篇
  1989年   347篇
  1988年   380篇
  1987年   342篇
  1986年   402篇
  1985年   366篇
  1984年   316篇
  1983年   296篇
  1982年   247篇
  1981年   209篇
  1980年   195篇
  1979年   268篇
  1978年   164篇
  1977年   139篇
  1976年   101篇
  1975年   120篇
  1974年   146篇
  1973年   114篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The disintegration of the Soviet Union had profound economic and social effects on many of the newly independent transition economies. Nowhere was this more so than in the fisheries sector – with one of the biggest production shortfalls occurring in Kyrgyzstan, following the collapse of lake capture and pond-culture production. In 2005, aggregate landings were just 48 tonnes – barely 3 per cent of the catch level recorded in 1989. This article has two objectives. First it analyses the extent to which the dissolution of the Soviet Union can explain the collapse of the fisheries sector in Kyrgyzstan. Second, in the light of these findings, it considers what practical steps, if any, might be taken to revitalize the sector.  相似文献   
992.
993.
994.
This article contains an examination of the way in which the largely British model of professional comprehensive housing management became important in Hong Kong. It shows how a comparatively small number of pioneers, mainly women who were followers of the principles of Octavia Hill, a philanthropic social reformer who developed her ideas in 19th century London, had a considerable influence in the very different environment of Hong Kong. An examination of the comparatively small amount of literature on the housing management profession is followed by a detailed analysis of the way in which the housing management profession has developed in Hong Kong. A review of the origin of public housing programmes in Hong Kong highlights the influence which housing professionals had when the housing administration was radically restructured at the time of the formation of the Hong Kong Housing Authority in the early 1970s.  相似文献   
995.
The National Institute of Forensic Toxicology, Oslo, receives blood and urine samples from all Norwegian drivers apprehended on suspicion of driving under the influence of alcohol or drugs. In 1983 we received samples from 1446 drug-suspected drivers, out of which 445 underwent toxicological analysis. The drugs found most frequently were tetrahydrocannabinol (THC) (n = 199), diazepam (n = 166) and amphetamine (n = 102). A cautious interpretation of the data indicate that about 200 of the 445 subjects selected for toxicological analysis drove under severe influence of drugs. Because of the high percentage of submitted cases not analysed for drugs, this figure represents a minimum estimate. Compared with the results from 1978, we found a several-fold increase in detections of THC and amphetamine in 1983. The number of diazepam detections did not increase in a similar way, but we estimated that the diazepam detections would have increased 3-fold if we had analysed as frequent for this drug in 1983 as in 1978.  相似文献   
996.
997.
Frontal sinuses of Japanese skulls were radiographically examined from the view point of identifying individuals. The system of classification of sinus was proposed, basing on the area size, the bilateral asymmetry, the superiority of side, the outline of upper borders, the partial septa and the supraorbital cells. Frontal sinus patterns could be divided into above 20,000 possible combinations by combining the class numbers in each classification item described above. The frontal sinus pattern of a given person was formulated as a code number which was determined by arranging the class numbers in each classification item as serial numbers. This identification system by the frontal sinus pattern should allow one to characterize each person. The application of this identification system to an actual criminal case was also described.  相似文献   
998.
An improved method for detecting diatom in blood is reported. Blood of cadavers was obtained by cardiac puncture at inquest or from the left atrium directly at autopsy. The blood was hemolyzed by sodium dodecyl sulfate (SDS) and filtered through membrane filter (47 mm in diameter and 5 microns in pore size). When the blood was putrefied, two or three pieces of membranes filters were needed because of choking membrane pore. The membrane filters were digested with fuming nitric acid and diluted with distilled water. The diluted solution was filtered through membrane filter (25 mm in diameter) again. After drying the membrane filter was immersed in oil. Diatoms on the membrane filter were clearly observed microscopically.  相似文献   
999.
A series of fatal motorcycle accidents from a 7-year period (1977-1983) has been analyzed. Of the fatalities 30 were operators of the motorcycle, 11 pillion passengers and 8 counterparts. Of 41 operators 37% were sober at the time of accident, 66% had measurable blood alcohol concentration (BAC); 59% above 0.08%. In all cases where a pillion passenger was killed, the operator of the motorcycle had a BAC greater than 0.08%. Of the killed counterparts 2 were non-intoxicated, 2 had a BAC greater than 0.08%, and 4 were not tested. The results advocate that the law should restrict alcohol consumption by pillion passengers as well as by the motorcycle operator. Suggestions made to extend the data base needed for developing appropriate alcohol countermeasures by collecting sociodemographic data on drivers killed or seriously injured should be supported.  相似文献   
1000.
Studies are reported on microbial conversion of various unsaturated fatty acids to 10-hydroxy and/or 10-oxo fatty acids by Micrococcus luteus. Four fatty acids possessing cis-9-unsaturation produced 10-hydroxy and 10-oxo fatty acid products, but three enoic acids possessing trans-9-unsaturation or double bond(s) in other than the 9-carbon position were inactive as substrates. 10-Hydroxy palmitic and stearic acids were converted to the corresponding 10-oxo fatty acids, but the 10-oxo compounds were inactive as substrates. This indicates that the metabolic sequence of cis-9-enoic fatty acid by the microbial enzyme(s) is first converted to 10-hydroxy fatty acid and then to its 10-oxo compound.  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