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   14279篇
  免费   421篇
各国政治   776篇
工人农民   577篇
世界政治   1149篇
外交国际关系   575篇
法律   8478篇
中国共产党   2篇
中国政治   183篇
政治理论   2856篇
综合类   104篇
  2020年   181篇
  2019年   238篇
  2018年   322篇
  2017年   328篇
  2016年   330篇
  2015年   259篇
  2014年   310篇
  2013年   1610篇
  2012年   363篇
  2011年   457篇
  2010年   340篇
  2009年   370篇
  2008年   405篇
  2007年   374篇
  2006年   356篇
  2005年   307篇
  2004年   362篇
  2003年   351篇
  2002年   259篇
  2001年   623篇
  2000年   578篇
  1999年   459篇
  1998年   220篇
  1997年   176篇
  1996年   160篇
  1995年   152篇
  1994年   152篇
  1993年   138篇
  1992年   269篇
  1991年   283篇
  1990年   266篇
  1989年   255篇
  1988年   267篇
  1987年   267篇
  1986年   255篇
  1985年   232篇
  1984年   228篇
  1983年   231篇
  1982年   146篇
  1981年   138篇
  1980年   111篇
  1979年   163篇
  1978年   117篇
  1977年   91篇
  1976年   92篇
  1975年   90篇
  1974年   96篇
  1973年   98篇
  1972年   88篇
  1971年   85篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Because of difficulties collecting sales taxes on Internet sales, several states have engaged in an effort (the Streamlined Sales Tax Project, SSTP) to simplify their sales tax systems. One hope among SSTP proponents is that a simplified system will result in Internet vendors voluntarily collecting the sales tax. We address two issues:
  • ? Will states adopt the extensive reforms proposed by the SSTP?
  • ? Will vendors voluntarily collect the sales tax?
We argue that states are unlikely to adopt extensive reforms, but if they did, many vendors would voluntarily collect sales taxes.  相似文献   
942.
Degradation of human DNA extracted from forensic stains is, in most cases, the result of a natural process due to the exposure of the stain samples to the environment. Experiences with degraded DNA from casework samples show that every sample may exhibit different properties in this respect, and that it is difficult to systematically assess the performance of routinely used typing systems for the analysis of degraded DNA samples. Using a batch of artificially degraded DNA with an average fragment size of approx. 200 bp a collaborative exercise was carried out among 38 forensic laboratories from 17 European countries. The results were assessed according to correct allele detection, peak height and balance as well as the occurrence of artefacts. A number of common problems were identified based on these results such as strong peak imbalance in heterozygous genotypes for the larger short tandem repeat (STR) fragments after increased PCR cycle numbers, artefact signals and allelic drop-out. Based on the observations, strategies are discussed to overcome these problems. The strategies include careful balancing of the amount of template DNA and the PCR cycle numbers, the reaction volume and the amount of Taq polymerase. Furthermore, a careful evaluation of the results of the fragment analysis and of automated allele calling is necessary to identify the correct alleles and avoid artefacts.  相似文献   
943.
Eight Y chromosome short tandem repeat (STR) polymorphisms (DYS19, DYS385, DYS389I, DYS389II, DYS390, DYS391, DYS392, and DYS393) were analyzed in the sample of 117 unrelated Albanian males living in Kosovo. A general STR allelic frequency pattern in the Albanian population from Kosovo corresponds to other European populations. Fourty six haplotypes were observed in single copy. The most frequent haplotypes were (DYS19-DYS385-DYS389I-DYS389II-DYS390-DYS391-DYS392-DYS393) 14-11/11-13-29-24-11-13-13 (10.26%), 14-14/17-12-28-24-10-11-12 (9.40%), 13-16/18-13-30-24-10-11-13 (9.40%), and 14-17/17-13-31-24-10-11-13 (9.40%).  相似文献   
944.
945.
Only approximately one-half of the 456 women who were killed or almost killed by a husband, boyfriend, or ex-husband or ex-boyfriend in a recent national study of homicide of women accurately perceived their risk of being killed by their abusive partner. Women are unlikely to overestimate their risk; however, many will underestimate the severity of the situation. From the same study, it was found that relatively few of the victims of actual or attempted intimate partner femicide were seen by domestic violence advocates during the year before they were killed; they were far more likely to be seen in the health care system. Implications are drawn as to innovative ways that women who are abused can be identified and with skilled assessment of the danger in their relationship helped make more informed plans for their safety.  相似文献   
946.
This analogue study (written vignettes and videotapes) examines the influence of victim-perpetrator relationship (spouse or acquaintance), sex of perceiver, and type of abuse (psychological vs. physical) on attributions about victims and perpetrators of domestic abuse. College student participants (73 men, 108 women) were randomly assigned to condition. As expected, type of relationship influenced observer perceptions. Specifically, participants rated the victim of marital violence as more psychologically damaged and disturbed by the abuse than the victim of acquaintance violence. Furthermore, interaction effects showed that men, more than women, rated the actions of the married perpetrator as more of a victim's rights violation than the actions of the acquaintance perpetrator. Second, type of abuse was shown to influence perceptions of the perpetrator but not the victim. Sex-of-perceiver effects were also obtained. Women held the perpetrator more responsible and assigned less blame to the victim than did men. Legal and clinical implications are then discussed.  相似文献   
947.
Privatisation, coupled with liberalisation and competition, constitutes one of the most popular policy options to improve the performance of state-owned enterprises. However, in Greece, it was only after 1991 that privatisation started to gain ground in the political and economic agendas of governments. Drawing upon the theoretical underpinnings of privatisation, the paper overviews and critically analyses the new legal framework on denationalisation in Greece. The paper argues that, though the modernisation of the legal regime is welcomed, the Greek government has failed to treat privatisation as part of wider structural reforms aiming at enhancing competition and foreign investment. The paper concludes that wider structural reforms, including regulatory reform and liberalisation, as well as combating corruption and bureaucracy and promoting transparent capital markets, are absolutely necessary in order to create a competitive environment, which would both complement and support privatisation efforts.  相似文献   
948.
Human subjects research has been the focus of numerous controversies over the years. The dilemma lies between the potential harm to individuals who participate in research and the knowledge to be gained from the research study that might benefit society. When research is conducted in developing countries by researchers and sponsors from the United States and other industrialized countries, differences in history, culture, politics, wealth, and power between the countries give rise to unique challenges. In this Article, the author identifies several ethical issues to be considered when research is conducted in developing countries and provides the legal and ethical framework for their resolution.  相似文献   
949.
950.
The purpose of this study was to evaluate the ability of two amphetamine class screening reagents to exclude ephedrine (EPH), pseudoephedrine (PSEPH), and phenylpropanolamine (PPA) from falsely producing positive immunoassay screening results. The study also sought to characterize the prevalence and concentration distributions of EPH, PSEPH, and PPA in samples that produced positive amphetamine screening results. Approximately 27,400 randomly collected human urine samples from Navy and Marine Corps members were simultaneously screened for amphetamines using the DRI and Abuscreen online immunoassays at a cutoff concentration of 500 ng/mL. All samples that screened positive were confirmed for amphetamine (AMP), methamphetamine (MTH), 3,4-Methylenedioxyamphetamine (MDA), 3,4-Methylenedioxymethamphetamine (MDMA), EPH, PSEPH, and PPA by gas chromatography/mass spectrometry (GC/MS). The DRI AMP immunoassay identified 1,104 presumptive amphetamine positive samples, of which only 1.99% confirmed positive for the presence of AMP, MTH, MDA, or MDMA. In contrast, the online AMP reagent identified 317 presumptive amphetamine positives with a confirmation rate for AMP, MTH, MDA, or MDMA of 7.94%. The presence of EPH, PSEPH, or PPA was confirmed in 833 of the 1,104 samples that failed to confirm positive for AMP, MTH, MDA, or MDMA; all of the 833 samples contained PSEPH. When compared to the entire screened sample set, PSEPH was present in approximately 3%, EPH in 0.9%, and PPA in 0.8% of the samples. The results indicate that cross reactivities for EPH, PSEPH, and PPA are greater than reported by the manufacturer of these reagents. The distribution of concentrations indicates that very large concentrations of EPH, PSEPH, and PPA are common.  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