全文获取类型
收费全文 | 6165篇 |
免费 | 245篇 |
专业分类
各国政治 | 445篇 |
工人农民 | 190篇 |
世界政治 | 622篇 |
外交国际关系 | 443篇 |
法律 | 2586篇 |
中国政治 | 50篇 |
政治理论 | 2003篇 |
综合类 | 71篇 |
出版年
2023年 | 41篇 |
2022年 | 26篇 |
2021年 | 54篇 |
2020年 | 106篇 |
2019年 | 152篇 |
2018年 | 167篇 |
2017年 | 199篇 |
2016年 | 203篇 |
2015年 | 117篇 |
2014年 | 173篇 |
2013年 | 1045篇 |
2012年 | 170篇 |
2011年 | 176篇 |
2010年 | 174篇 |
2009年 | 180篇 |
2008年 | 158篇 |
2007年 | 220篇 |
2006年 | 193篇 |
2005年 | 226篇 |
2004年 | 229篇 |
2003年 | 214篇 |
2002年 | 230篇 |
2001年 | 120篇 |
2000年 | 116篇 |
1999年 | 99篇 |
1998年 | 90篇 |
1997年 | 94篇 |
1996年 | 90篇 |
1995年 | 94篇 |
1994年 | 94篇 |
1993年 | 78篇 |
1992年 | 85篇 |
1991年 | 92篇 |
1990年 | 63篇 |
1989年 | 66篇 |
1988年 | 64篇 |
1987年 | 63篇 |
1986年 | 71篇 |
1985年 | 62篇 |
1984年 | 56篇 |
1983年 | 64篇 |
1982年 | 48篇 |
1981年 | 56篇 |
1980年 | 39篇 |
1979年 | 38篇 |
1978年 | 33篇 |
1977年 | 33篇 |
1976年 | 31篇 |
1974年 | 16篇 |
1967年 | 14篇 |
排序方式: 共有6410条查询结果,搜索用时 390 毫秒
841.
842.
Repeated exposure to electro-muscular incapacitating devices could result in repetitive, sustained muscle contraction, with little or no muscle recovery period. Therefore, rhabdomyolysis and other physiological responses, including acidosis, hyperkalaemia, and altered levels of muscle enzymes in the blood, would be likely to occur. Experiments were performed to investigate effects of repeated exposures of TASER International's Advanced TASER X26 on muscle contraction and resultant changes in blood factors in an anaesthetized swine model. A total of 10 animals were used. Six swine were exposed for 5 s, followed by a 5-s period of no exposure, repeatedly for 3 min. (In five of the animals, after a 1-h delay, a second 3-min exposure period was added.) The remaining four animals were used for an additional pilot study. All four limbs of each animal exhibited contraction even though the electrodes were positioned in areas at some distances from the limbs. The degree of muscle contraction generated during the second exposure period was significantly lower than that in the first exposure series. This finding was consistent with previous studies showing that prolonged activity in skeletal muscle will eventually result in a decline of force production. There were some similarities in blood sample changes in the current experiments with previous studies of muscular exercise. Thus problems concerning biological effects of repeated TASER exposures may be related, not directly to the "electric output" per se, but rather to the resulting contraction of muscles (and related interruption of respiration) and subsequent sequelae. Transient increases in hematocrit, potassium, and sodium were consistent with previous reports in the literature dealing with studies of muscle stimulation or exercise. It is doubtful that these short-term elevations would have any serious health consequences in a healthy individual. Blood pH was significantly decreased for 1h following exposure, but subsequently returned toward a normal level. Leg muscle contractions and decreases in respiration each appeared to contribute to the acidosis. Lactate was highly elevated, with a slow return (time course greater than 1 h) to baseline. Other investigators have reported profound metabolic acidosis during restraint-associated cardiac arrest. Since restraint often occurs immediately after TASER exposure, this issue should be considered in further development of deployment concepts. On the basis of the results of the current studies, the repeated use of electro-muscular incapacitating devices in a short period of time is, at least, feasible, with the caveat that some medical monitoring of subjects may be required (to observe factors such as lactate and acidosis). 相似文献
843.
Given the DNA profiles of two individuals and one parent (say the mother) of each, we present likelihood ratios (LRs) comparing the hypothesis that they have the same father with the hypothesis of unrelated fathers. If the individuals have the same mother, the problem is to distinguish full- from half-siblings, otherwise we are comparing a half-sibling relationship with unrelated. We simulate STR profiles at up to 60 loci, based on allele proportions observed at 15 loci in three populations, and use them to approximate misclassification rates both for binary classification (e.g. "half-sib" versus "unrelated"), and when a third "cannot say" category is included. We find that reliable inferences in the absence of the mothers' profiles require many more STR loci than the 10-25 loci that are currently routinely available. However, profiling the two mothers conveys more discriminatory power than profiling the same number of additional loci in the individuals themselves. Our likelihood ratio formulas include a theta (or Fst) adjustment to allow for the individuals concerned to have recent shared ancestry (coancestry), relative to the population from which the allele frequency database is drawn. We illustrate that using an appropriate value of theta can reduce the average misclassification rate. 相似文献
844.
Kerr FC 《Forensic science international》2006,162(1-3):44-48
The ever-increasing size of digital media presents a continuous challenge to digital investigators who must rapidly assess computer media to find and identify evidence. To meet this challenge, methods must continuously be sought to expedite the examination process. This paper investigates using the file ownership property as an analytical tool focusing on activity by individuals associated with the computer. Research centered on the New Technology File System (NTFS), which is the default file system in Microsoft Windows Operating System (OS). This was done because Microsoft's worldwide market penetration makes Windows and NTFS the most likely OS and file system to be encountered in digital forensic examinations. Significantly, digital forensic software now allows examination of NTFS file attributes and properties including the ownership property. The paper outlines potential limitations regarding interpreting ownership findings, and suggests areas for further research. Overall, file ownership is seen as a potentially viable new digital forensic tool. 相似文献
845.
846.
847.
848.
849.
850.
David L. Carter 《Journal of criminal justice》1985,13(6):487-500
This exploratory study examines relationships between the police and Hispanics in Texas. Specifically, data were collected on Hispanic evaluations of police performance, expectations of police performance, and overall satisfaction with the police. A sample of 500 Hispanics throughout the state of Texas were surveyed on their experienced and perceived relationships with three levels of police agencies: local (municipal) police, sheriff's officers, and the state's Department of Public Safety. Findings are reported based upon overall ratings of the police, victim-related data, and data from individuals who had any form of contact with the police. Significant findings show that any form of contact with the police appeared to lower the rating of police performance. This appears to be a product of the interaction between high public expectations and qualitatively poor police performance. Further findings indicate that an increase in the fear of crime among Hispanics lowered evaluations of local police. Similarly, victimization lowered the evaluation of local police, the county sheriff, and the Department of Public Safety. Hispanics also perceived that officers have a “bad attitude,” that the police need to patrol and investigate more, that response time should be improved, and that there should be less discrimination against Hispanics. These findings appear to be largely influenced by ineffective communication (both symbolic and linguistic) and cultural conflict. 相似文献