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   10661篇
  免费   589篇
各国政治   441篇
工人农民   368篇
世界政治   834篇
外交国际关系   309篇
法律   7164篇
中国共产党   1篇
中国政治   54篇
政治理论   2034篇
综合类   45篇
  2021年   61篇
  2020年   194篇
  2019年   240篇
  2018年   239篇
  2017年   299篇
  2016年   305篇
  2015年   250篇
  2014年   273篇
  2013年   1025篇
  2012年   240篇
  2011年   311篇
  2010年   292篇
  2009年   301篇
  2008年   287篇
  2007年   262篇
  2006年   283篇
  2005年   251篇
  2004年   254篇
  2003年   238篇
  2002年   242篇
  2001年   465篇
  2000年   422篇
  1999年   296篇
  1998年   183篇
  1997年   148篇
  1996年   129篇
  1995年   121篇
  1994年   146篇
  1993年   133篇
  1992年   199篇
  1991年   220篇
  1990年   206篇
  1989年   218篇
  1988年   208篇
  1987年   193篇
  1986年   238篇
  1985年   209篇
  1984年   160篇
  1983年   173篇
  1982年   114篇
  1981年   123篇
  1980年   88篇
  1979年   134篇
  1978年   75篇
  1977年   74篇
  1976年   70篇
  1974年   76篇
  1973年   67篇
  1972年   67篇
  1970年   47篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
961.
European Journal of Political Research -  相似文献   
962.
A simple method was devised to assess dental attrition in terms of its area and number of sites by using dental plaster casts and a computer assisted image analyser. The changes presented on the occlusal surfaces of teeth were investigated for age estimation using these criteria. The area of attrition on each tooth demonstrated a significant positive correlation with age, but a wide individual variation was observed in the values for each tooth. Therefore, this method was unsuitable for accurate age estimation of a single tooth. A strong negative correlation with age was observed in the number of sites of attrition. A multiple stepwise regression analysis using the variables 'attrition area' and 'attrition number' revealed multiple correlation coefficient values of 0.93. The quantitative assessment of both horizontal and vertical factors of dental attrition would be essential to improve the accuracy of this method.  相似文献   
963.
A 23-year-old man was found on a raised hide in lying position, the head wrapped in a plastic bag connected with a helium gas cylinder by a polypropylene tube. The autopsy did not show any specific findings nor did the routine toxicological analysis reveal significant information regarding the cause of death (BAC 0.9 mg/g, diphenhydramine 0.81 μg/ml in heart serum). For the detection of helium in the lungs, gas samples from both lungs were collected by a method ensuring minimal dilution. Gas analyses were performed using a GC–MS with a split–splitless injector and a headspace syringe. As carrier gas the commonly used helium was replaced by nitrogen. Helium was found in clearly elevated concentrations in gas samples from both lungs. Therefore, suffocation by breathing helium enriched, and thus oxygen deficient atmosphere, can strongly be assumed as the cause of death.  相似文献   
964.
965.
Abstract: A new screening method for detecting gamma-hydroxybutyric acid (GHB) in drink matrices, using the IonSense, Inc. (Saugus, MA) direct analysis in real time (DART) ion source coupled to a JEOL exact mass time-of-flight mass spectrometer (AccuTOF), was validated and compared with the current screening methodology. The DART ion source allows for analysis of samples under ambient conditions with little to no sample preparation. Fifty drink specimens were spiked at levels of 1, 2, 3, and 4 mg/mL GHB, and analyzed on the AccuTOF-DART. Positive detection of GHB occurred for each of the samples at each concentration level, giving 100% accuracy for the samples tested. Twenty-five of the 50 drink specimens were spiked at 1 mg/mL GHB and tested using a color test known as the GHB Color Test #3. Only two of these 25 specimens tested positive for the presence of GHB, giving only 8% accuracy. Implementation of this new methodology as a screening tool for GHB analysis will quickly eliminate negative specimens allowing the examiner to focus analysis time on those that screened positive.  相似文献   
966.
The intradural sagittal diameter at the second cervical vertebra (SD/C2) of 62 SIDS cases was measured myelographically. This SD/C2 proved to be dependent on body size, body weight, and age. A clear, age-dependent difference is to be found in the primarily narrow spinal canal. This parameter (SD/C2), which is more precisely defined in adults on the basis of clinical, radiological, and autopsical findings is assumed to have the value of 0.5 cm in the first 2 months, 0.6 cm in the third month, and 0.65 cm in the fourth month. The resulting potential danger to infants is dependent upon their position. The SD/C2, was significantly decreased in extension as compared to a neutral posture. With consideration of the primarily narrow spinal canal in the infant, there is, according to our measurements, a potential hazard for the infant in any further, significant shortening of the SD/C2. This is independent of the width of the spinal canal under maximal extension. We found individual cases in which the SD/C2 was decreased by almost 50% from the normal value in neutral position. No correlation was found between the primary width of the spinal canal and the degree of luminal reduction upon extension.  相似文献   
967.
Felsenthal  Dan S.  Machover  Moshé 《Public Choice》1998,96(1-2):81-92
We consider a system made up of two committees, with overlapping membership but with different rules for passing decisions; the passage of a joint resolution requires separate approval by each committee. We show that it is possible for one voter a to be stronger (have greater voting power) than another voter b in both of the two committees, while in the two-committee system (considered as a single composite entity) b is stronger than a. We argue that this apparently paradoxical phenomenon is inherent in the structure of the decision-making system in question, rather than being an artefact of any particular index used to measure voting power.  相似文献   
968.
969.
As punishment for lying, the foster mother of a five-year-old white male poured pepper into his throat. He immediately became dyspneic, then apneic, and was pronounced dead about 1 h later. At autopsy, the main stem and several smaller bronchi were occluded with pepper. Mechanisms of asphyxia by pepper include mechanical obstruction of the tracheobronchial tree and mucosal edema caused by the irritant effect of volatile oils in pepper. This rare circumstance represents the second reported fatal case of pepper aspiration and the third reported case overall.  相似文献   
970.
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