全文获取类型
收费全文 | 27410篇 |
免费 | 1419篇 |
国内免费 | 1篇 |
专业分类
各国政治 | 1156篇 |
工人农民 | 1174篇 |
世界政治 | 1949篇 |
外交国际关系 | 935篇 |
法律 | 18212篇 |
中国共产党 | 3篇 |
中国政治 | 174篇 |
政治理论 | 5088篇 |
综合类 | 139篇 |
出版年
2021年 | 153篇 |
2020年 | 548篇 |
2019年 | 607篇 |
2018年 | 783篇 |
2017年 | 793篇 |
2016年 | 865篇 |
2015年 | 670篇 |
2014年 | 724篇 |
2013年 | 2900篇 |
2012年 | 694篇 |
2011年 | 759篇 |
2010年 | 749篇 |
2009年 | 797篇 |
2008年 | 762篇 |
2007年 | 751篇 |
2006年 | 758篇 |
2005年 | 666篇 |
2004年 | 698篇 |
2003年 | 575篇 |
2002年 | 595篇 |
2001年 | 1099篇 |
2000年 | 951篇 |
1999年 | 770篇 |
1998年 | 392篇 |
1997年 | 294篇 |
1996年 | 290篇 |
1995年 | 304篇 |
1994年 | 286篇 |
1993年 | 277篇 |
1992年 | 521篇 |
1991年 | 526篇 |
1990年 | 504篇 |
1989年 | 493篇 |
1988年 | 491篇 |
1987年 | 481篇 |
1986年 | 492篇 |
1985年 | 501篇 |
1984年 | 414篇 |
1983年 | 393篇 |
1982年 | 298篇 |
1981年 | 284篇 |
1980年 | 219篇 |
1979年 | 364篇 |
1978年 | 210篇 |
1977年 | 168篇 |
1976年 | 142篇 |
1975年 | 169篇 |
1974年 | 209篇 |
1973年 | 173篇 |
1972年 | 144篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
71.
Isolation of the DNA minisatellite probe MZ 1.3 and its application to DNA 'fingerprinting' analysis 总被引:1,自引:0,他引:1
U Schacker P M Schneider B Holtkamp E Bohnke R Fimmers H H Sonneborn C Rittner 《Forensic science international》1990,44(2-3):209-224
A minisatellite probe, MZ 1.3, detecting hypervariable fragment patterns was isolated from a human genomic library. A repetitive sequence of 27 bp length was identified which is contained in the probe approx. 40 times. The MZ 1.3 repeat shows variable homology of 53-73% to the repetitive sequence of the protein III gene of the bacteriophage M13 genome. Polymorphic restriction fragment patterns were found with MZ 1.3 using the enzymes Hinf I, BstN I, Hae III, Mbo I, PstI/Pvu II, and Rsa I. An average of 18 polymorphic fragments was observed using Hinf I as enzyme. The band sharing frequency after Hinf I digestion among unrelated individuals was determined to be 23.8 +/- 7.2%. An example for the application of MZ 1.3 to paternity testing in an incest case is given. The probe can be used with radioactive or non-radioactive detection systems. An approach is presented to compare polymorphic fragment patterns from individuals obtained by independent gel runs on the basis of relative band positions (RBP) and calculated in a computerized analysis. 相似文献
72.
Good gas chromatography (GC) separation of molecules is essential for clean gas chromatography/mass spectrometry (GC/MS) confirmation of compounds. The trifluoro derivatives of ephedrine (E) and methamphetamine (MA) coelute on dimethyl silicone capillary columns, such as DB-1, which are most commonly used by chromatographers. Methods are described to separate E and MA to aid GC/MS confirmations of methamphetamine, ephedrine, or both E and MA together, whichever may be present in Enzyme Immunoassay (EIA)-analyzed amphetamine-positive urine samples. The use of the heptafluoro derivatives of E and MA on a DB-1 column, or the trifluoro derivatives of E and MA on a DB-17 column, is suggested for good gas chromatographic separation. 相似文献
73.
One case of the erroneous administration of deslanoside and high level of drug in antemortem plasma and postmortem specimens has been reported owing to the unusual surrounding circumstances. Deslanoside in antemortem plasma was determined by FPIA and the analysis was done by HPLC in the postmortem tissue samples. The analytical results and methods used in the examinations are discussed in the following paper. 相似文献
74.
75.
The effect of various stain carriers on the quality and quantity of DNA extracted from dried bloodstains 总被引:1,自引:0,他引:1
Bloodstains were made with 200 microliters blood on each of 11 different common substrates to examine the effect of the stain carrier on the amount and quality of DNA recoverable. High-molecular-weight DNA was extracted from all samples after 2 days. The yield of DNA from each sample varied considerably, not only between the different stain carriers but also within a given category. With a DNA yield of up to 10 micrograms, paper, glass, nylon, wood, smooth leather and wool gave the best results, followed by blue denim and wallpaper (up to 6 micrograms), cotton fabric and carpeting (up to 4 micrograms) and suede (up to 2 micrograms). For several stain carriers the DNA-containing solution was contaminated by chemical substances, which in the case of the blue denim, suede, and carpet samples inhibited the digestion of the DNA with restriction enzymes and prevented DNA typing. The different textures of the stain carriers tested and (as for varying yields on the same carrier) the differing degree of loss of DNA during extraction and the physiological variation in the number of leukocytes in human blood are discussed as possible reasons for the wide range of variation in the amounts of DNA it was possible to extract. 相似文献
76.
77.
On the basis of the uncertainty management model, we argue here that when people are uncertain about an organization's trustworthiness, they may resolve the question how they should react toward the organization by relying on their perceptions of the organization's procedures. As a consequence, we predicted that the reactions of parents whose child was in a day care center would be strongly influenced by their perceptions of the procedures used by the organization that was responsible for their children's day care when the parents would be uncertain about the organization's trustworthiness. However, when parents would be certain that the organization could be trusted they would be less in need of procedural information, yielding less strong effects of perceived procedure on parents' reactions. The findings of a survey study corroborate this line of reasoning. In the discussion it is argued that these findings suggest that people especially rely on their perceptions of procedures when they are uncertain about important aspects of their lives, such as the trustworthiness of organizations that are responsible for their children's day care. 相似文献
78.
D J WILLIAMS WILLIAM B. STREAN ENRIQUE GARCIA BENGOECHEA 《Juvenile & family court journal》2002,53(2):31-41
This article discusses relevant literature on the potential benefits of sport, recreation, and leisure, and how these benefits relate to rehabilitation of juveniles. Many professionals involved in juvenile rehabilitation believe sport and recreation are beneficial adjuncts to treatment programming; however, it can be difficult to structure sport and recreation in ways that directly correspond to treatment goals. The purpose of this article is to provide insights for professionals working with juveniles on how sport and recreation programming can be an effective means of helping to achieve rehabilitation goals. Attention is given to approaches, particularly the Teaching Games for Understanding model (Bunker & Thorpe, 1982), which can be used to effectively link recreation and sport to the rehabilitation process. 相似文献
79.
This article outlines the new regionalism movement and its metropolitanagenda, reviews federal efforts to promote new regionalism underISTEA and TEA21, considers how the new federal policieschanged the role of metropolitan planning organizations (MPOs)in transportation planning by examining the MPO for the Louisvillemetropolis, and assesses the MPO process in Louisville. Thelocal decision of whether to build a new bridge across the OhioRiver was a major test of the enhanced MPO process. Federaltransportation policies enhanced regional coordination and cooperationin transportation planning in the Louisville metropolis resultingin a consensus plan to build two bridges across the Ohio River.However, the MPO process did not lead to the development ofa metropolitan-wide interest or perspective. Moreover, the newregionalist agenda was not advanced because sprawl was not afactor in the decision on whether and where to build the bridges. 相似文献
80.