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   3429篇
  免费   56篇
各国政治   97篇
工人农民   93篇
世界政治   145篇
外交国际关系   95篇
法律   2650篇
中国政治   17篇
政治理论   351篇
综合类   37篇
  2020年   33篇
  2019年   34篇
  2018年   54篇
  2017年   42篇
  2016年   63篇
  2015年   28篇
  2014年   51篇
  2013年   245篇
  2012年   86篇
  2011年   133篇
  2010年   79篇
  2009年   61篇
  2008年   108篇
  2007年   121篇
  2006年   106篇
  2005年   84篇
  2004年   121篇
  2003年   113篇
  2002年   108篇
  2001年   150篇
  2000年   134篇
  1999年   103篇
  1998年   20篇
  1995年   17篇
  1993年   27篇
  1992年   62篇
  1991年   83篇
  1990年   85篇
  1989年   91篇
  1988年   95篇
  1987年   89篇
  1986年   75篇
  1985年   77篇
  1984年   67篇
  1983年   58篇
  1982年   24篇
  1981年   20篇
  1979年   30篇
  1978年   33篇
  1977年   22篇
  1976年   27篇
  1975年   28篇
  1974年   37篇
  1973年   37篇
  1972年   35篇
  1971年   36篇
  1970年   38篇
  1969年   32篇
  1968年   27篇
  1967年   18篇
排序方式: 共有3485条查询结果,搜索用时 15 毫秒
231.
232.
233.
This paper discusses results of a supercritical fluid extraction-gas chromatography/mass spectrometry (SFE-GC/MS) study of small samples ( 100 microg to 1 mg) of human scalp hair. The method offers a number of benefits including greater sensitivity than liquid extraction methods because the entire extractable mass is transferred to the analytical system, compared with only a few percent from a conventional liquid extraction/injection. The project's goals were to determine if SFE-GC/MS analyses of the surface-extractable components of an individual's hair yield consistent chemical profiles and to investigate if the profiles are sufficiently different to distinguish them from those of other individuals. In addition, the mtDNA sequences from ten of the same individuals used in the SFE-GC/MS study from four family units were determined, and, while the families were distinguishable, the maternal relations yielded identical sequences. In tandem, SFE-GC/MS and mtDNA techniques may provide valuable complementary data from forensic hair samples.  相似文献   
234.
The results of extraction of 1,2- and 1,4-dihydroxybenzene from water solutions by the hydrophobic and hydrophilic organic solvents are described. The influence of an extragent nature and of a water-phase pH medium on an extraction degree is demonstrated. The repetition factor needed to extract a preset quantity of examined compounds is calculated.  相似文献   
235.
236.
With due regard for the economic situation in regions, differences in the material-technical and personnel provision of each forensic-medical bureau (FMB), paying capacity of local residents and for other factors, a method for estimating the cost of forensic medical services was elaborated and offered for use. The formula of cost estimation for rendered services allow for basic wages (BW) and bonuses, sick-list and vacation payments, overhead charges (including FMB wear-and-tear), and BW assignment to off-budget funds (which constitute, in total, the self-cost of services) as well as the planned profit and road taxes.  相似文献   
237.
A total of 743 lethal outcomes of thromboembolytic complications of trauma, diseases and certain pathological conditions as observed in 1999-2001 and in the three quarters of 2002 were studied. The undertaken analysis confirmed two factors provoking the pathological thrombosis, i.e. 1. Pathological changes observed in the surface vascular wall preconditioned by mechanical damages, atherosclerotic process and aging; and 2. A slower blood flow due to an impaired blood circulation, a forced positioning and to hypodynamics. While deciding on a possibility of a direct cause-effect relation between past traumas, surgeries, poisonings and death of thromboembolism of the pulmonary arteries (TEPA), such relation can be mentioned only on rare occasions. It is more often the case that an indirect, mediated relationship is found, when TERA evolves due to an unfavorable combination of risk factors, i.e. a forced immobility, changing coagulated blood system, impaired blood vessels etc.  相似文献   
238.
The case study was based on the osteologic collection of the chair for anthropology, State Moscow University, including the male carpal bones (67) and female carpal bones (13), aged above 18 to 20. Four measurements were made according to Martin's scheme for metacarpal bones and finger phalanxes. A diagnostic method was worked out on the bases of the discriminative analysis, with such method enabling the remodeling of the ordinal localization of metacarpal bones as well as of main, medium and distal phalanxes. The maximally accurate classification was ensured for metacarpal bones, ranging from 81.5% to 100%; and the minimally accurate one was achieved for distal phalanxes, ranging from 20% to 95%. The discriminative analysis results were checked for distal phalanxes by Neklyudov's series (male--100, female--85); they were described according to 7 sizes. However, an attempt to enhance the accuracy of the classification of these phalanxes failed. The offered method should be applied in combination with the traditional anatomic-and-morphological method; besides, if possible, it is necessary to check the congruence of joint surfaces in the metacarpal interphalangeal joints.  相似文献   
239.
A possibility was studied to use the plaster copies of skulls in the forensic medical identification of personality by applying the craniofacial method. No dependence was found between the plaster casts and the moulding types. Differences between the same craniometric sizes in the skull and in its cast are of an incidental nature. Such incidental deviation is related with an accuracy of determining the localization of craniometric points and with an instrumental precision of measuring devices. The necessity is substantiated that, while making a craniofacial examination, it is necessary to mark all anthropometric points in the skull cast, with the original being a control. The use of a plaster skull cast is possible in those cases, when the burial of the remains must be done in full.  相似文献   
240.
Eighteen cadavers of persons, who died of acute and chronic alcohol and drug intoxication (ephedron-addiction), were used to study the changes in the spinal nerve plexuses and external genitals. The activity of acetylcholinesterase and of NADPH-diaphorase was determined histochemically; the adrenergic nerve fibers were detected by a glyoxyl-acid technique. Rectified changes in the relative density of adrenal-cholinergic- and nitroxydergic structures and in the activity of mediators in different intoxications were found. The chronic intoxication by alcohol and ephedron was accompanied by a reduced activity of enzymes involved in the metabolism of acetylcholine, nitric oxide and catecholamines. A lower density was observed in the nerve fibers that contained the examined substances. The results can be used as an additional criterion in evaluating the male sexual-function status.  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