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   4778篇
  免费   171篇
  国内免费   5篇
各国政治   313篇
工人农民   135篇
世界政治   422篇
外交国际关系   310篇
法律   1869篇
中国共产党   14篇
中国政治   478篇
政治理论   1318篇
综合类   95篇
  2021年   29篇
  2020年   45篇
  2019年   70篇
  2018年   109篇
  2017年   117篇
  2016年   114篇
  2015年   80篇
  2014年   100篇
  2013年   762篇
  2012年   182篇
  2011年   361篇
  2010年   252篇
  2009年   219篇
  2008年   216篇
  2007年   129篇
  2006年   143篇
  2005年   146篇
  2004年   140篇
  2003年   103篇
  2002年   120篇
  2001年   86篇
  2000年   97篇
  1999年   71篇
  1998年   63篇
  1997年   72篇
  1996年   48篇
  1995年   56篇
  1994年   65篇
  1993年   59篇
  1992年   47篇
  1991年   64篇
  1990年   41篇
  1989年   58篇
  1988年   35篇
  1987年   42篇
  1986年   40篇
  1985年   44篇
  1984年   32篇
  1983年   45篇
  1982年   42篇
  1981年   51篇
  1980年   39篇
  1979年   44篇
  1978年   39篇
  1977年   20篇
  1976年   32篇
  1975年   20篇
  1974年   21篇
  1973年   21篇
  1969年   17篇
排序方式: 共有4954条查询结果,搜索用时 28 毫秒
961.
掠夺性定价一般表现为企业为排挤、制约竞争对手或阻碍竞争对手进入市场而在相当长的一段时期内故意将价格设置于其成本之下。其目的是为将竞争对手逐出市场并随后设定高于竞争水平的价格,以收回前期降价的损失。《中华人民共和国反垄断法》以及其他相关的法律法规都包含了禁止掠夺性定价的规定。然而,对于掠夺性定价中的一些具体问题还没有相应的法制规章提供指引和解读,再加上此类案件法院判决的先例在中国现阶段还属少见,因此,本文将详细讲解近年来美国和欧盟的经济学家、反垄断机构以及法院对此类经典案件(如Wanadoo案等)的审理分析经验与趋势,以供借鉴。  相似文献   
962.
While the High Court accepted that there was some similaritybetween Kenwood's new kMix mixer and the KitchenAid Artisanfood mixer (the ‘Artisan mixer’) manufactured anddistributed by Whirlpool, it rejected Whirlpool's claims fortrade mark infringement and passing off because such similaritywas insufficient to cause confusion in the mind of the averagedesign conscious consumer, or to cause detriment to the distinctivecharacter or repute of Whirlpool's mark.  相似文献   
963.
Calcified tissues, such as bone and tooth, and some other sample types, such as those containing adhesive, present a challenge to standard extraction protocols. We have developed a lysis reagent, BTA™ lysis buffer, which is designed for use with PrepFiler™ Kit reagents. The BTA™ lysis buffer disrupts calcified tissue matrices and achieves effective extraction of DNA from pulverized bone and tooth samples. In addition, the BTA™ lysis buffer mildly but efficiently extracts DNA from challenging substrates like tape, chewing gum, and cigarette butts and, as with bone and tooth, DNA from these lysates is purified using established PrepFiler™ reagent extraction protocols.We successfully extracted DNA from powdered human bone samples, chewed gum and smoked cigarettes using BTA™ lysis buffer. Extraction yields for bone, gum and cigarette samples tested were consistent and reproducible. This extraction method efficiently removed potential PCR inhibitors from all samples tested, and CT values for the internal PCR control of Quantifiler® Human DNA Quantification Kit were consistent and within the normal range. The DNA extracted from these samples also provided conclusive profiles that were free of PCR artifacts when amplified using the AmpF?STR® Identifiler® PCR Amplification Kit. The protocol is easily adapted for automation.  相似文献   
964.
A developmental validation study based on recommendations of the Scientific Working Group on DNA Analysis Methods (SWGDAM) was conducted on a multiplex system of 10 Cannabis sativa short tandem repeat loci. Amplification of the loci in four multiplex reactions was tested across DNA from dried root, stem, and leaf sources, and DNA from fresh, frozen, and dried leaf tissue with a template DNA range of 10.0-0.01 ng. The loci were amplified and scored consistently for all DNA sources when DNA template was in the range of 10.0-1.0 ng. Some allelic dropout and PCR failure occurred in reactions with lower template DNA amounts. Overall, amplification was best using 10.0 ng of template DNA from dried leaf tissue indicating that this is the optimal source material. Cross species amplification was observed in Humulus lupulus for three loci but there was no allelic overlap. This is the first study following SWGDAM validation guidelines to validate short tandem repeat markers for forensic use in plants.  相似文献   
965.
It has been estimated that women involved in street prostitution are 60 to 100 times more likely to be murdered than are nonprostitute females. In addition, homicides of prostitutes are notoriously difficult to investigate and, as such, many cases remain unsolved. Despite this large risk factor, little literature exists on homicides of prostitutes, and there is a lack of basic statistics and knowledge regarding this very specific victim group that could possibly help investigators. The aim of the current study is to conduct an exploratory study to explore the key characteristics of this group and how they differ from other subgroups of homicide. Forty-six cases of U.K. prostitute homicides are analyzed and compared to 59 male offender-female victim nonsexual homicide cases and 17 male offender-female victim sexual homicide cases.  相似文献   
966.
Abstract:  Three cases are reported of elevated postmortem blood morphine concentrations (189–3036 ng/mL) that were observed during the course of death investigations involving three children ranging in age from 1 week to 2 years, all of whom underwent withdrawal of life support. In all three cases, the presence of opiates in postmortem blood was indicated by immunoassay (ELISA) and quantitative confirmatory analysis of free morphine concentrations in postmortem blood was performed by solid-phase extraction followed by gas chromatography/mass spectrometry (GC/MS) in the selected ion monitoring mode. While the practice of withdrawing life support from terminally ill patients, with the accompanying administration of narcotics/analgesics has been reported in the medical literature, it has not been adequately described in the forensic literature. The implications of this practice on the forensic toxicological interpretation of morphine findings are discussed. To our knowledge, this is the first report of postmortem morphine concentrations arising directly from administration in conjunction with withdrawal of care in pediatric patients.  相似文献   
967.
Detection of ketamine exposure in skeletal tissues by automated enzyme-linked immunosorbent assay (ELISA) and gas chromatography with electron capture detection (GC-ECD) is described. Rats (n = 18) received 0, 15, 30, or 75 mg/kg ketamine hydrochloride acutely (i.p.), and were euthanized within 15 min or 1 h. Ketamine was extracted from ground femoral bone by methanolic incubation followed by liquid-liquid extraction (LLE), while marrow was homogenized in alkaline solution, and then underwent LLE. Extracts were analyzed by ELISA, and subsequently by GC-ECD following derivatization with trifluoroacetic acid anhydride. The effect of tissue type (i.e., diaphyseal bone vs. epiphyseal bone vs. bone marrow) on the immunoassay response was examined through determination of binary classification test sensitivity (S) and measurement of the relative decrease in absorbance (%DA, drug-positive tissues vs. drug-free controls) in each tissue type. The %DA varied significantly between different tissues examined under a given dose condition, and generally decreased in the order marrow > epiphyseal bone > diaphyseal bone, at all dose levels examined. Measured S values for marrow, epiphyseal bone, and diaphyseal bone were 100%, 77%, and 23%, respectively (75 mg/kg dose). These results suggest that the type of skeletal tissue sampled and position sampled within a given bone (diaphyses vs. epiphyses) are important parameters in drug screening of skeletal tissues.  相似文献   
968.
969.
The Turning Point Model State Public Health Act (Turning Point Act), published in September 2003, provides a comprehensive template for states seeking public health law modernization. This case study examines the political and policy efforts undertaken in Alaska following the development of the Turning Point Act. It is the first in a series of case studies to assess states' consideration of the Turning Point Act for the purpose of public health law reform. Through a comparative analysis of these case studies and ongoing legislative tracking in all fifty states, researchers can assess (1) how states codify the Turning Point Act into state law and (2) how these modernized state laws influence or change public health practice, leading to improved health outcomes.  相似文献   
970.
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