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   1137篇
  免费   94篇
各国政治   127篇
工人农民   76篇
世界政治   131篇
外交国际关系   61篇
法律   663篇
中国政治   4篇
政治理论   168篇
综合类   1篇
  2023年   21篇
  2022年   7篇
  2021年   30篇
  2020年   40篇
  2019年   48篇
  2018年   77篇
  2017年   96篇
  2016年   68篇
  2015年   59篇
  2014年   65篇
  2013年   176篇
  2012年   57篇
  2011年   45篇
  2010年   21篇
  2009年   21篇
  2008年   44篇
  2007年   45篇
  2006年   43篇
  2005年   40篇
  2004年   43篇
  2003年   47篇
  2002年   37篇
  2001年   25篇
  2000年   17篇
  1999年   8篇
  1998年   4篇
  1997年   4篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1993年   2篇
  1992年   2篇
  1991年   3篇
  1990年   1篇
  1989年   1篇
  1988年   2篇
  1984年   2篇
  1983年   2篇
  1981年   2篇
  1980年   3篇
  1979年   4篇
  1978年   1篇
  1977年   2篇
  1976年   1篇
  1974年   4篇
  1972年   3篇
  1968年   1篇
  1967年   1篇
  1966年   1篇
  1964年   1篇
排序方式: 共有1231条查询结果,搜索用时 93 毫秒
31.
Allele and genotype frequencies for three recently described short tandem repeat loci D1S1656, D12S391, and D18S535 were determined in a population sample from Asturias (North Spain). The loci were amplified using a fluorescence based PCR method and were typed automatically. No deviation from Hardy-Weinberg expectations were observed. The three loci proved to be highly discriminating and the allele frequencies observed are similar to those of the other European populations that have been typed for these loci to date.  相似文献   
32.
The amplification of the STR DYS391, using the primers described in the Genome Data Base (GDB: G00-365-251), shows not only an additional band to the Y-specific one in males with a size range of 26 bp less than those of DYS391 locus alleles, but also a polymorphic pattern in females in the same size range as the additional band observed in males. The DYS391 pattern in families reflects a Y-specific linked locus and also a polymorphic X locus with an X-linked pattern of inheritance. A first screening in the X homologous locus allowed the identification of five different alleles. Allele frequencies were explored in different population groups for both the Y locus and the homologous locus in the X chromosome showing a similar allele distribution pattern in the X and Y homologous loci. An alternative reverse primer was designed to amplify the Y-chromosome specific STR in order to improve the specificity and applicability of this system to forensic genetics. Comparative results of the amplification with the new and the previously described primers proved that with this new primer there is a substantial increase in the specificity of the amplification. Moreover, a smaller fragment is amplified with a size out of the range of the alleles of the other Y-STRs usually used in forensic applications, therefore simplifying its inclusion in multiplex systems.  相似文献   
33.
ABSTRACT

This paper analyzes simultaneous strikes during the first half of the 20th century in North America. The transformation of production in copper, lead, zinc, and silver mining districts determined the formation of a working class that operated between Mexico and the United States. Therefore, the labor conflicts combined market circumstances and management-imposed homologation of work structures across firm divisions with the international coordination of miners. The paper describes the emergence, growth, and demise of a regional industrial system.  相似文献   
34.
“Albeit democratic, their coat of arms has pride of place”. Thus Romualdo Nogués defined, in 1890, Spanish collectors of bourgeois origin who had joined the ranks of the aristocracy. A few years later, in 1924, the Duke of Alba’s maiden speech at the Academia de Bellas Artes de San Fernando justified his personal artistic worthiness on the basis of his ancestors’ collecting activities and the artworks they had amassed.

These two examples set the scene for the research questions studied in this monographic issue. The present introduction offers a bird’s eye view of the phenomenon and continues with a few remarks about the House of Osuna which, as is well known, occupied a pivotal position in Spanish nobility during the whole of the second half of the nineteenth century.  相似文献   

35.
36.
A clear positive case for anabolic steroids doping was confounded by alleged urine tampering during doping control procedures. Review of the chain of custody showed no flaws, but nevertheless the athlete was adamant that the urine sample should be analyzed for DNA in order to support her contention that she was not the donor of the sample. The results obtained showed that the urine sample that scored positive for steroids contained nuclear DNA that could not be matched to the DNA obtained from the athlete's blood. On the other hand, the same urine sample contained mitochondrial DNA whose nucleotide sequences spanning the hyper variable regions HV1 and HV2 proved to be identical to those determined in mitochondrial DNA amplified from the athlete's blood. The occurrence of an extraneous genotype is compatible with exogenous nuclear DNA admixture to the athlete's urine. Alternatively, taking in consideration the mitochondrial DNA, we could not exclude that a sibling or a maternal relative of the athlete could have acted as a donor of the urine utilized for doping control and DNA analysis. Both situations point to possible tampering of the urine by the athlete. Adjudication at CAS maintained previous national and international federation decision that there was no proof of a chain of custody flaw to justify the athlete's allegation of urine substitution after collection.  相似文献   
37.
Nine Y-STR loci from the "minimal haplotype" included in Y-STR Haplotype Reference Databases (YHRD) together with eight additional Y-STRs (DYS437, DYS438, DYS439, DYS460, DYS461, GATA C4, GATA H4 and GATA A10) were analyzed in a sample of 101 males from Equatorial Guinea living in Madrid. Haplotype and allelic frequencies were calculated and genetic diversities were estimated for each genetic system as well as for the whole haplotype. An unexpected high frequency (6%) of intermediate alleles (13.2 and 14.2) was found in DYS385. For DYS19, two alleles were found in one sample. Another sample failed to amplify with DYS393 primers using either PowerPlex Y System (Promega Corporation) or the Y-PLEXtrade mark 12 (Reliagene, New Orleans, LA) commercial kits. Comparison between Equatorial Guinea and another African population (Mozambique; South East Coast) revealed a significant pairwise Phi(st) value between them (Phi(st)=0.03309; P=0.00000).  相似文献   
38.
The 11 Y-chromosomal short tandem repeats (STRs) included in the Promega Corporation PowerPlex Y System (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385, DYS437, DYS438 and DYS439) were typed in three ethnic groups ("Andalusians", Berber and Arab) and one cosmopolitan population (Tunis) from Tunisia, summing up 247 individuals, and 139 different haplotypes. Focusing the analysis on the seven Y-STRs of the YHRD Minimal Haplotype Core (DYS385 excepted), "Andalusians" showed no differences from the Cosmopolitan and the Arab samples previously published (our Arab sample presented an extremely low haplotype diversity), but were different from the Berbers. The Berbers from Tunisia were not different from those from Morocco.  相似文献   
39.
A qualitative and quantitative analytical method was developed and validated for the determination of 49 licit and illicit drugs in oral fluid. Small oral fluid samples, volume 1mL, were collected from volunteers using a modified Omni-Sal device and the analytes were extracted from an oral fluid/buffer mixture using a single Bond Elut Certify solid phase extraction cartridge. Liquid chromatography-tandem mass spectrometry (LC-MS-MS) and gas chromatography-repetitive full scan mass spectrometry (GC-MS) were used in parallel to analyze the extracts for the targeted drugs. Extracts were analyzed by GC-MS in their underivatized form and as their pentafluoropropionyl derivatives. Deuterated internal standards were used for quantification of drugs of abuse by LC-MS-MS to minimize matrix effects. Methadone-d(9) and tumoxetine were used as the internal standards for quantification of non-derivatized and derivatized analytes respectively by GC-MS. Linearity was demonstrated over the range 5-200 ng/mL and limits of detection were less than 4 ng/mL for each drug analyzed. The method demonstrated acceptable recoveries for most of the analytes and good intra- and inter-day precision. Acquisition of data by repetitive full scan GC-MS allows the addition of further analytes to the target menu.  相似文献   
40.
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