全文获取类型
收费全文 | 9972篇 |
免费 | 274篇 |
专业分类
各国政治 | 382篇 |
工人农民 | 427篇 |
世界政治 | 750篇 |
外交国际关系 | 382篇 |
法律 | 6316篇 |
中国政治 | 72篇 |
政治理论 | 1878篇 |
综合类 | 39篇 |
出版年
2023年 | 58篇 |
2021年 | 66篇 |
2020年 | 123篇 |
2019年 | 175篇 |
2018年 | 231篇 |
2017年 | 210篇 |
2016年 | 231篇 |
2015年 | 135篇 |
2014年 | 204篇 |
2013年 | 978篇 |
2012年 | 240篇 |
2011年 | 279篇 |
2010年 | 204篇 |
2009年 | 253篇 |
2008年 | 272篇 |
2007年 | 263篇 |
2006年 | 255篇 |
2005年 | 196篇 |
2004年 | 244篇 |
2003年 | 221篇 |
2002年 | 181篇 |
2001年 | 480篇 |
2000年 | 447篇 |
1999年 | 323篇 |
1998年 | 137篇 |
1997年 | 137篇 |
1996年 | 103篇 |
1995年 | 105篇 |
1994年 | 104篇 |
1993年 | 87篇 |
1992年 | 221篇 |
1991年 | 222篇 |
1990年 | 240篇 |
1989年 | 222篇 |
1988年 | 228篇 |
1987年 | 229篇 |
1986年 | 187篇 |
1985年 | 191篇 |
1984年 | 166篇 |
1983年 | 147篇 |
1982年 | 105篇 |
1981年 | 114篇 |
1980年 | 73篇 |
1979年 | 121篇 |
1978年 | 77篇 |
1975年 | 65篇 |
1974年 | 87篇 |
1973年 | 80篇 |
1972年 | 60篇 |
1970年 | 54篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Juvenile delinquency is a major public concern in the United States, and increasingly in many other industrialized countries. The last few years have seen a decline in officially recorded juvenile delinquency (Snyder, 1997). However, projections are that with the anticipated increase of the U.S. teenage population because of the echo baby boom generation, serious juvenile crime will substantially increase in the next few years (see Fox, 1996). 相似文献
962.
963.
964.
965.
966.
967.
Contrary to the image of college campuses as “ivory towers,” the victimization of college students recently has been portrayed as a serious problem deserving policy intervention. Based on interviews designed after the National Crime Victimization Survey, which were conducted with 3,472 randomly selected students across 12 institutions, we examined both the level and sources of students'victimization. More than one-third of the sample reported being victims during the 1993–94 academic year. Informed by the lifestyle-routine activities approach, the analysis revealed that the risk of property victimization was increased by proximity to crime, target attractiveness, exposure, and lack of guardianship. The main predictor of violent victimization was a lifestyle that included high levels of partying on campus at night and the recreational use of drugs. 相似文献
968.
Critical studies of an intricate blunt force injury pattern in a brutal homicide led to the identification of the murder weapon. A 50-year-old male was bludgeoned to death in his apartment during a robbery allegedly engineered by his daughter. Careful measurements and overlay construction of the wounds relative to the magazine catch, lanyard ring, magazine chamber, and butt of a 32-caliber Eistegui Hermanos fibar (Espa?a) automatic pistol led to the conclusion that either the alleged weapon or one identical to it caused the fatal injuries. 相似文献
969.
Lyophilized Sigma Type III trypsin has been applied to latent prints two weeks to two months old. This trypsin preparation eliminates the background problems that had been encountered with old prints in a previous study. Zinc chloride treatment of latent prints previously exposed to ninhydrin enhances their detectability upon laser examination. However, it has been reported that the zinc chloride reaction occasionally fails to occur. Accordingly, we have investigated the optimization of this reaction. We find that high humidity and elevated temperature, particularly the former, are needed. Cadmium nitrate, although it produces weaker fluorescence than zinc chloride, may at times be useful. Reaction conditions are much the same as those for zinc chloride. 相似文献
970.
Nuclear spin tomography since its beginnings in the seventies has steadily gained in importance as a method of examination in medical diagnostics as it produces a picture. In the field of forensic medicine the NMR technique as used for anatomic-anthropologic issues attempting to identify skulls this is a valuable supplement to an extension of the existing methods of investigation. The results of a measurement of the thickness of soft facial tissue in a live test person is shown as compared to measures obtained by sonography. 相似文献