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   1732篇
  免费   95篇
各国政治   115篇
工人农民   74篇
世界政治   157篇
外交国际关系   145篇
法律   932篇
中国共产党   1篇
中国政治   14篇
政治理论   375篇
综合类   14篇
  2023年   23篇
  2022年   25篇
  2021年   25篇
  2020年   49篇
  2019年   69篇
  2018年   76篇
  2017年   86篇
  2016年   87篇
  2015年   64篇
  2014年   75篇
  2013年   250篇
  2012年   80篇
  2011年   65篇
  2010年   54篇
  2009年   62篇
  2008年   65篇
  2007年   97篇
  2006年   69篇
  2005年   74篇
  2004年   57篇
  2003年   49篇
  2002年   46篇
  2001年   23篇
  2000年   27篇
  1999年   28篇
  1998年   19篇
  1997年   14篇
  1996年   8篇
  1995年   17篇
  1994年   12篇
  1993年   3篇
  1992年   22篇
  1991年   8篇
  1990年   9篇
  1989年   10篇
  1988年   8篇
  1987年   7篇
  1986年   7篇
  1985年   7篇
  1984年   4篇
  1983年   7篇
  1982年   4篇
  1981年   2篇
  1980年   4篇
  1977年   3篇
  1975年   4篇
  1973年   3篇
  1969年   3篇
  1968年   2篇
  1966年   3篇
排序方式: 共有1827条查询结果,搜索用时 15 毫秒
101.
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   
102.
103.
A method for the selenium determination in a mother and her child's hair using palladium as a chemical modifier was optimized. The sample was digested with nitric acid and hydrogen peroxide and diluted to 5 ml. To achieve complete mineralization the samples were ashed at 1200 degrees C in the presence of palladium as a chemical modifier. The optimum atomization temperature was 1900 degrees C. The precision and accuracy of the method were studied using the reference material CRM 397. Results of calibration using aqueous standards and the standard addition method were compared. The method was applied to the selenium determination in 30 samples of the mother's and child's hair. The levels found were 0.54 +/- 0.34 microgram/g for mother's hair and 0.77 +/- 0.25 microgram/g for child's hair.  相似文献   
104.
“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   

105.
106.
107.
In the present longitudinal 3-wave study of 1274 adolescents and young adults, aged 12–24 at the 1st wave, it is examined whether youngsters from intact versus postdivorce families show long-term differences in internalizing and externalizing problems. Furthermore, possible differences in the development of this problem behavior between offspring from intact and postdivorce families are examined, i.e., possible differences in growth curves of internalizing and externalizing problems are investigated. Longitudinal multilevel analyses reveal long-term differences in internalizing and externalizing problems according to family structure. Adolescents and young adults growing up in postdivorce families display more internalizing and externalizing problem behavior than youngsters of intact families. The development of these 2 types of problem behavior does not differ by gender or family structure. That is, the shape of the growth curves of internalizing and externalizing problem behavior is similar for boys and girls and also for youngsters from intact and postdivorce families. Inge VanderValk is a Postdoc Researcher at the Department of Child and Adolescent Studies, Utrecht University, the Netherlands. She received her Ph.D. in 2004 from Utrecht University. Her major research interests include associations between adolescent adjustment and parental marital quality and parental divorce. Ed Spruijt is an Associate Professor at the University of Utrecht. He received his Ph.D. in 1983 from Utrecht University. His major research interests are the consequences of parental divorce and visitation arrangements on children. Martijn de Goede is an associate Professor at Utrecht University, Department of Methodology and Statistics. He received his Ph.D. in 1988 from Utrecht University. His major research interests are occupational and relational life courses of youngsters. Cora Maas is an Assistent Professor at Utrecht University, Department of Methodology and Statistics. She received her PH.D. in 1992 in Utrecht from Utrecht University. Her major interests are: multilevel analysis (theory and applications). Wim Meeus is full Professor of Adolescent Development at Utrecht University. He received his Ph.D. in 1984 from Utrecht University. His major research interests are personality, identity, and relationships in adolescence.  相似文献   
108.
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   
109.
110.
Validation of a recently proposed differentiation method for single poly (ethylene terephthalate) (PET) fibers, based on integration of IR absorption bands, is presented. IR microscopy in the transmission mode, differential scanning calorimetry and optical microscopy were employed. The reliability of the technique has been extended to the cases in which the fibers being compared have experienced long exposure to the elements, as may happen if these items are recovered from open-air crime scenes. The effect of immersion in water and irradiation by the sun for a three-month period have been considered. The fibers remained morphologically and structurally unaltered. The significance of comparisons between fibers kept in different environments is thus enhanced, because the detrimental effect of the elements can be ruled out. This further validation of the proposed technique contributes to render the data presented by the forensic scientist less vulnerable to context effect and bias.  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