全文获取类型
收费全文 | 807篇 |
免费 | 18篇 |
专业分类
各国政治 | 20篇 |
工人农民 | 86篇 |
世界政治 | 65篇 |
外交国际关系 | 27篇 |
法律 | 382篇 |
中国政治 | 16篇 |
政治理论 | 212篇 |
综合类 | 17篇 |
出版年
2022年 | 7篇 |
2021年 | 2篇 |
2020年 | 11篇 |
2019年 | 11篇 |
2018年 | 17篇 |
2017年 | 13篇 |
2016年 | 25篇 |
2015年 | 17篇 |
2014年 | 19篇 |
2013年 | 105篇 |
2012年 | 33篇 |
2011年 | 25篇 |
2010年 | 24篇 |
2009年 | 11篇 |
2008年 | 32篇 |
2007年 | 35篇 |
2006年 | 37篇 |
2005年 | 42篇 |
2004年 | 35篇 |
2003年 | 29篇 |
2002年 | 31篇 |
2001年 | 16篇 |
2000年 | 17篇 |
1999年 | 9篇 |
1998年 | 12篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 10篇 |
1994年 | 11篇 |
1993年 | 10篇 |
1992年 | 12篇 |
1991年 | 15篇 |
1990年 | 13篇 |
1989年 | 9篇 |
1988年 | 20篇 |
1987年 | 12篇 |
1986年 | 12篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1974年 | 3篇 |
1973年 | 2篇 |
排序方式: 共有825条查询结果,搜索用时 0 毫秒
51.
Although the topic of recidivism invariably elicits much interest, there appears to be considerable conflict and uncertainty as to even crude estimates of the recidivism rate for persons released from prison. The purpose of this research was to examine the extent to which this apparent confusion may be explained by different methodological choices of criterion measure or length of follow-up. Through the cooperation of the Federal Bureau of Investigation, rap sheet follow-up information for a six-year period was obtained for a relatively large random sample of federal prisoners released in 1970. This data enabled calculation of recidivism rates using various criterion measures and follow-up periods applied to the same sample. The effect of varying these definitions on the recidivism rate obtained can then be directly observed. 相似文献
52.
53.
54.
55.
Contrary to apparent differences in timing and style between Harold D. Lasswells political psychology and the policy sciences approach that he pioneered, the continuity and compatibility between the two are very high. The appropriateness of Lasswells political psychology framework for addressing the intellectual tasks of the policy sciences is demonstrated by linking the insights of his political psychology to the policy sciences framework, and reviewing the common pragmatist philosophy underlying both his political psychology and the policy sciences. 相似文献
56.
57.
The utility of pulmonary interstitial emphysema (PIE) in live birth determination is not well established. Because the distinction between live birth and stillbirth may be important in criminal proceedings, we undertook this study to investigate the relationship between the histologic finding of PIE and live birth. Sixty-six cases of infant death were retrieved and compared with 21 stillborn infants. Histologic sections of the lungs were characterized as "florid PIE," "equivocal PIE," or "absent PIE." Sixteen cases of florid PIE were identified, all in live born infants. Forty-seven cases of equivocal PIE were found in 36 live born and 11 stillborn infants. In 24 cases (14 live born infants and 10 stillborns), no PIE was identified. We examined the relationship between florid PIE in infants with sudden infant death syndrome (SIDS) or "sudden unexpected death in infancy, manner undetermined" (SUDI), and also its relationship to other variables. No association was found. The presence of equivocal PIE may be an artifact of tissue processing. Florid PIE is found only in live born infants. No correlation between the presence of florid PIE and cause of death could be determined. 相似文献
58.
59.
Low concentrations of THC and 11-hydroxy-THC in serum samples are often claimed not to result from recent cannabis use. Prediction of time of exposure is difficult, especially if distinctive features of drug use could not be observed. Therefore, the aim of the study was to investigate the presence of THC and 11-hydroxy-THC in serum samples as well as to obtain preliminary data on the analyte profile for a time window of 24-48 hours after discontinuation of cannabis smoking. Serum samples from heavy (n = 12, > 1 joint/day), moderate (n = 11, < or = 1 joint/day) and light (n = 6, < 1 joint/week) smokers of cannabis were analyzed for THC, 11-hydroxy-THC and free THC-COOH by GC/MS as well as for glucuronidated THC-COOH by LC/MS-MS. The blood samples were collected 24-48 hours after abstaining from cannabis use. Additionally, 8 specimens were obtained from persons after discontinuation of the drug for more than 48 hours. During collection of the blood samples, distinctive effects due to drug use could not be observed. For heavy users of cannabis, THC was detectable in 8 samples, and in 5 cases both biologically active compounds, THC and 11-hydroxy-THC, were present (1.3-6.4 ng THC/mL serum, 0.5-2.4 ng 11-hydroxy-THC/mL serum). Among moderate users, in 1 sample 1.8 ng THC/mL serum and 1.3 ng 11-hydroxy-THC/mL serum were determined, and another sample was tested positive with low concentrations close to the limit of detection. In serum samples of light users both analytes could not be detected, indicating that in those persons a positive finding of THC and 11-hydroxy-THC may rather result from recent consumption than from cannabis use 1 or 2 days prior to blood sampling. The concentrations of THC-COOH and its glucuronide covered a wide range in all groups of cannabis users. However, there was a trend to higher concentrations in heavy users compared to moderate users, and the mean concentration was smaller in light smokers than in moderate smokers. Overall, the findings indicated that data from pharmacokinetic studies should be supplemented by data obtained from "real-life" samples. 相似文献
60.
Benner BA Goodpaster JV DeGrasse JA Tully LA Levin BC 《Journal of forensic sciences》2003,48(3):554-563
This paper discusses results of a supercritical fluid extraction-gas chromatography/mass spectrometry (SFE-GC/MS) study of small samples ( 100 microg to 1 mg) of human scalp hair. The method offers a number of benefits including greater sensitivity than liquid extraction methods because the entire extractable mass is transferred to the analytical system, compared with only a few percent from a conventional liquid extraction/injection. The project's goals were to determine if SFE-GC/MS analyses of the surface-extractable components of an individual's hair yield consistent chemical profiles and to investigate if the profiles are sufficiently different to distinguish them from those of other individuals. In addition, the mtDNA sequences from ten of the same individuals used in the SFE-GC/MS study from four family units were determined, and, while the families were distinguishable, the maternal relations yielded identical sequences. In tandem, SFE-GC/MS and mtDNA techniques may provide valuable complementary data from forensic hair samples. 相似文献