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   6143篇
  免费   190篇
各国政治   472篇
工人农民   166篇
世界政治   656篇
外交国际关系   385篇
法律   2552篇
中国政治   38篇
政治理论   1986篇
综合类   78篇
  2023年   27篇
  2020年   76篇
  2019年   107篇
  2018年   134篇
  2017年   158篇
  2016年   171篇
  2015年   117篇
  2014年   157篇
  2013年   978篇
  2012年   153篇
  2011年   188篇
  2010年   155篇
  2009年   149篇
  2008年   199篇
  2007年   263篇
  2006年   196篇
  2005年   184篇
  2004年   204篇
  2003年   197篇
  2002年   194篇
  2001年   114篇
  2000年   122篇
  1999年   94篇
  1998年   132篇
  1997年   111篇
  1996年   109篇
  1995年   86篇
  1994年   73篇
  1993年   87篇
  1992年   80篇
  1991年   95篇
  1990年   80篇
  1989年   75篇
  1988年   79篇
  1987年   92篇
  1986年   93篇
  1985年   55篇
  1984年   72篇
  1983年   73篇
  1982年   68篇
  1981年   54篇
  1980年   52篇
  1979年   44篇
  1978年   45篇
  1977年   46篇
  1976年   26篇
  1975年   26篇
  1974年   29篇
  1973年   37篇
  1968年   24篇
排序方式: 共有6333条查询结果,搜索用时 0 毫秒
251.
252.
253.
254.
East Asian governments have engaged in unprecedented collaborationon trade and financial matters since the economic crises of1997. For some observers, such activity, building on a new senseof shared identity forged by resentment at Western responsesto the crises, is a significant step towards the formation ofan East Asian economic bloc. In reality, the new collaborationhas produced only modest results. Neither an East Asian preferentialtrade agreement nor an Asian Monetary Fund is likely to materialize.Underlying power realities and fundamental economic interestsare unchanged. The new interest in negotiating preferentialtrade agreements (many of which are with countries outside ofEast Asia) is best explained by government perceptions of theeffectiveness of such arrangements elsewhere in the global economy,and by a desire to increase bargaining power.  相似文献   
255.
With increasing frequency, relatively small, fragmentary evidence thought to be osseous or dental tissue of human origin is submitted to the forensic laboratory for DNA analysis with the request for positive identification. Prior to performing DNA analysis, however, it is prudent to first perform a presumptive test or "screen" to determine whether the questioned material may be eliminated from further consideration. When material is shown not to be consistent with bone/teeth, DNA testing is not performed. When such determinations cannot be made from gross morphological features, elemental analysis can be indicative. This presumptive test is made possible by applying scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) in conjunction with an X-ray spectral database recently developed by the FBI laboratory. This database includes spectra for many different materials including known examples of bone and tooth from many different contexts and representing the full range of taphonomic conditions. Results of SEM/EDS analysis of evidence can be compared to these standards to determine if they are consistent with bone and/or tooth and, if not, then what the material might represent. Analysis suggests that although the proportions and amounts of calcium and phosphorus are particularly important in differentiating bone and tooth from other materials, other minor differences in spectral profile can also provide significant discrimination. Analysis enables bone and tooth to be successfully distinguished from other materials in most cases. Exceptions appear to be ivory, mineral apatite, and perhaps some types of corals.  相似文献   
256.
Laser desorption mass spectrometry (LDMS) may be used for the detection and identification of dyes found in inks. Naturally-aged and artificially-aged blue and black ballpoint pen inks containing the cationic dye methyl violet were analyzed on paper. The average molecular weight of the dye sample was calculated from LD mass spectral data and plotted versus time. The resulting aging curves demonstrate that, as dye degradation increases, the average molecular weight of the dye decreases. Typical variables involved in ink aging, such as the type of paper and ink formulation, were investigated. Results show that these variables influence the rate of dye degradation. Furthermore, UV accelerated aging has been developed and tested as an alternative to thermal approaches.  相似文献   
257.
A study of 30 cases of violence from a total sample of 199 cases of infant abductions between the years 1983 and 2000 included a subsample of six (or 20%) where the kidnapping was by cesarean section. The six cases are classified by type of crime. Four cases were classified as personal cause homicide, subtype cesarean section homicide; one case classified as personal cause, subtype domestic homicide, and one case classified as a criminal enterprise homicide. The behavioral profiles of the abductors included a confidence style approach to the victim mother, deception, and planning of the cesarean section. The forensic psychodynamics suggest a dual motive to cement a failing partner relationship and to fulfill a childbearing and delivery fantasy. Cesarean section murder suggests a new category of personal cause homicide.  相似文献   
258.
259.
Diagnostic problems associated with cadaveric trauma from animal activity   总被引:2,自引:0,他引:2  
Analysis of a series of deaths between 1986 and 2001 resulting from natural disease, accidents, suicides, and homicide, where postmortem animal activity had traumatized bodies, was undertaken at the Forensic Science Center in Adelaide to demonstrate the range of lesions that may occur and problems in interpretation that result. Tissue damage had been caused by a variety of animals, including fly larvae, ants, birds, dogs, rodents, sea lice, and sharks. Postmortem animal activity had disguised injuries, modified wounds, and created the appearances of inflicted injury. Problems with identification occurred after postmortem facial trauma, and loss of organ parenchyma had interfered with, or precluded, the precise determination of the manner of death in some cases. Specific kinds of tissue and organ damage may occur after death, necessitating careful assessment of lesions in a search for characteristic features of animal activity. The pattern of lesions may enable identification of the particular species of animal involved.  相似文献   
260.
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