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   12141篇
  免费   678篇
各国政治   570篇
工人农民   461篇
世界政治   1019篇
外交国际关系   431篇
法律   7960篇
中国共产党   1篇
中国政治   59篇
政治理论   2263篇
综合类   55篇
  2023年   58篇
  2021年   92篇
  2020年   249篇
  2019年   316篇
  2018年   332篇
  2017年   405篇
  2016年   410篇
  2015年   315篇
  2014年   375篇
  2013年   1291篇
  2012年   322篇
  2011年   375篇
  2010年   333篇
  2009年   335篇
  2008年   350篇
  2007年   333篇
  2006年   330篇
  2005年   287篇
  2004年   300篇
  2003年   271篇
  2002年   262篇
  2001年   487篇
  2000年   447篇
  1999年   306篇
  1998年   196篇
  1997年   155篇
  1996年   128篇
  1995年   129篇
  1994年   151篇
  1993年   141篇
  1992年   201篇
  1991年   223篇
  1990年   207篇
  1989年   215篇
  1988年   206篇
  1987年   196篇
  1986年   232篇
  1985年   210篇
  1984年   165篇
  1983年   170篇
  1982年   114篇
  1981年   120篇
  1980年   85篇
  1979年   132篇
  1978年   74篇
  1977年   75篇
  1976年   70篇
  1974年   77篇
  1973年   67篇
  1972年   70篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
871.
872.
873.
874.
875.
876.
Sethi S  Bhargava SC 《危机》2003,24(1):4-6
Suicide in a family is distressing for each and every member. Children and adolescents bereaved by suicide are known to be more at risk of suffering from a variety of psychiatric problems, especially affective disorders. A group of children and adolescents who experienced a suicidal death in the family were assessed for psychiatric problems as well as for social adjustment. The findings suggest that the bereaved children and adolescents are at elevated risk for major depressive disorder, posttraumatic stress disorder, and impaired social adjustment.  相似文献   
877.
The estimation of time since the latest discharge of pistols and revolvers has been achieved by the Solid Phase Microextraction (SPME) sampling technique and the GC/TEA analytical system. The TEA2 compound, which in our previous work (1) was observed in barrels of shotguns and rifles as well as inside spent cartridges, was also detected in pistols and revolvers. The amount of this compound was very low in short-barreled small arms and its escape from the barrel could generally be measured for only a few days or up to two weeks after the latest discharge. To improve the detection of TEA2 compound, the SPME sampling time was prolonged and fibers coated by Carboxen/polydimethylsiloxane were used. The decrease of the TEA2 peak with time after shooting from pistols is nonexponential but the curve-fitting procedure proposed for the estimation of time since discharge of shotguns and rifles is difficult to apply as the decay is very rapid. Therefore, the detection of TEA2 compounds in small arms should be interpreted that the firearm had been used very recently. The amount of volatile decomposition products of smokeless powder increased significantly with the length of the barrel when firearms of the same caliber, but with different barrel lengths were investigated.  相似文献   
878.
The use of Japanese swords for homicidal attempts is rare. A Japanese samurai sword is a sharp and cutting object. When faced with the use of this weapon, one must distinguish between stabs and incised wounds. Incised wounds can rarely lead to death, but because of the size of the weapon, stabs usually cause much more serious injuries. Stabs also imply a penetrating movement, whereas incised wounds can be the consequence of protective circular blows. Therefore, it is important to distinguish clinically between these two kinds of wounds. We report a case where the perpetrator argued he had given a circular blow, unfortunately hitting the victim. The pieces of evidence are discussed.  相似文献   
879.
This work presents a novel collection method for gunshot residues (GSR) using a sampling procedure based on ethylenediaminetetraacetic acid (EDTA) solution as a complexing agent on moistened swabs. Detection was via a sector-field inductively coupled plasma mass spectrometry (HRICP-MS). The proposed collection and analytical method allowed detection of antimony (Sb), barium (Ba) and lead (Pb) after .38 shot tests. at detection limits of less than 1 microg L(-1) in four different areas of the hands of volunteers. This paper includes a discussion concerning hand areas near the thumb and forefinger as being more suitable for GSR collection as well as a comparison between differences observed using 2% diluted EDTA. 2% nitric acid solution, and simple deionized water as collecting solutions, proving the superior efficiency of EDTA in GSR recoveries.  相似文献   
880.
Thermal transfer printing refers to printing processes that utilize heat to produce an image by either physical or chemical means or by a combination of both. As the technology has improved and the supplies have become less expensive, the use of thermal printing in the personal and business markets has increased significantly. Specifically, dye diffusion thermal transfer and thermal mass transfer have become predominant in the production of counterfeit credit cards, drivers' licenses, and other types of documents produced on plastic media. Chemical analysis by means of thin layer chromatography (TLC) has proven to be useful in characterizing various types of inks (e.g., writing and inkjet inks). In this study, the authors examined 81 different samples that included a total of 54 printer samples (43 photographic prints on paper and eleven plastic card samples) and 27 printer ribbons. A new TLC method was developed and tested utilizing a solvent system (80% n-hexane, 3% methyl ethyl ketone, and 17% ethyl acetate) that is capable of producing excellent resolution.  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