全文获取类型
收费全文 | 10557篇 |
免费 | 291篇 |
专业分类
各国政治 | 397篇 |
工人农民 | 378篇 |
世界政治 | 710篇 |
外交国际关系 | 285篇 |
法律 | 6702篇 |
中国政治 | 67篇 |
政治理论 | 2221篇 |
综合类 | 88篇 |
出版年
2020年 | 102篇 |
2019年 | 155篇 |
2018年 | 190篇 |
2017年 | 218篇 |
2016年 | 212篇 |
2015年 | 161篇 |
2014年 | 182篇 |
2013年 | 941篇 |
2012年 | 215篇 |
2011年 | 263篇 |
2010年 | 210篇 |
2009年 | 266篇 |
2008年 | 268篇 |
2007年 | 269篇 |
2006年 | 261篇 |
2005年 | 241篇 |
2004年 | 234篇 |
2003年 | 242篇 |
2002年 | 235篇 |
2001年 | 423篇 |
2000年 | 366篇 |
1999年 | 294篇 |
1998年 | 158篇 |
1997年 | 122篇 |
1996年 | 136篇 |
1995年 | 132篇 |
1994年 | 133篇 |
1993年 | 134篇 |
1992年 | 232篇 |
1991年 | 251篇 |
1990年 | 240篇 |
1989年 | 248篇 |
1988年 | 225篇 |
1987年 | 223篇 |
1986年 | 262篇 |
1985年 | 256篇 |
1984年 | 229篇 |
1983年 | 214篇 |
1982年 | 151篇 |
1981年 | 127篇 |
1980年 | 113篇 |
1979年 | 151篇 |
1978年 | 85篇 |
1977年 | 111篇 |
1976年 | 95篇 |
1975年 | 71篇 |
1974年 | 89篇 |
1973年 | 83篇 |
1972年 | 78篇 |
1971年 | 69篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
Demographic and trend analysis of 881 consecutive suicides in blacks and whites is presented. For the years 1975 through 1984, the suicide rate was 15.1/100 000 and did not significantly change. White males were overrepresented in all age groups, had an overall suicide rate of 34.9, and showed a small but statistically significant increase in rate which was not accounted for by any specific age group. White females, in general, were represented in proportion to their prevalence in the population, and those ages 20 to 24 demonstrated an increasing suicide rate which was small. Black males were at highest risk in their twenties, showed no significant trends, and were also represented near their prevalence in the population. Black females of all ages were underrepresented, and had low suicide rates which decreased with time. No significant rate changes were noted for teenagers or the elderly. Firearms was the method of choice in all groups, although methods varied with age, race, and sex, and male children preferred hanging. Small but significant increases were noted for the prevalence of nondrug methods in females and carbon monoxide deaths in white males. Similarities and differences to larger scale studies are discussed. Suicide may have characteristics unique to given geographical areas and pervasive to all areas. The authors advocate study and publication of local data to clarify further the nature of suicide. 相似文献
972.
Detection of cocaine metabolite in perspiration stain, menstrual bloodstain, and hair 总被引:2,自引:0,他引:2
Low nanogram and picogram quantities of cocaine metabolite equivalents were detected in extracts from perspiration stains, menstrual bloodstains, and hair using radioimmunoassay. The theory of drug inclusion in hair and its significance are discussed. 相似文献
973.
974.
The interpretation of bloodstain patterns at crime scenes has received increased attention in recent years. Important to an understanding of this is knowledge of the fundamentals of blood droplet formation and impact dynamics. A review of the literature reveals that a considerable amount of work has been done with aqueous drop dynamics. Workers in the forensic science area seem to have been unaware of this. In addition, some of the most important and comprehensive early work with blood droplet dynamics seems to have been forgotten. It is not cited in more recent publications dealing with bloodstain pattern interpretation. This literature is reviewed and discussed as well. The present study presents results of experiments with blood droplet dynamics and high-speed photographs of blood droplet impacts on stationary target surfaces. Some longstanding misconceptions of importance to forensic scientists engaged in crime scene reconstruction are discussed. 相似文献
975.
976.
A method for the demonstration of the topographical distribution of phenobarbital at the cellular level in various tissues was established. Mice that had been exposed to various doses of phenobarbital by intraperitoneal injection were killed, and their tissues were fixed with 0.1 M phosphate buffer solution (pH 7.4) containing paraformaldehyde and glutaraldehyde. Thereafter, paraffin and frozen sections were made and stained by the indirect immunoperoxidase method using antisera obtained from commercial sources and used for the immunochemical assay of the blood level of phenobarbital in clinical medicine. A specific positive reaction was observed solely in testing the intoxicated tissues, and this reaction was inhibited when phenobarbital was added to the antisera. The minimal sensitivity of the positive reaction, which can be discerned by observing the stained slides macroscopically, was in the range of 10 mg/kg. Thus, the diagnosis of phenobarbital intoxication in the forensic autopsy can be made by immunohistochemistry. A positive reaction was found in various tissue cells, including nerve cells, myelin sheaths, glia cells, hepatocytes, cells of the alveolar and bronchial wall, epithelial cells of the distal part of the renal tubules, and so forth. Endothelial cells of the capillaries in all tissues gave a strong positive reaction. The immunocytochemical electron microscopy of the hepatocytes revealed that the positive reaction in the cytoplasm was located solely in the intraluminal space of the smooth endoplasmic reticulum. These results indicate some interesting aspects of the pharmacokinetics of phenobarbital in vivo. It is expected that the antisera, which are used widely for the assay of the blood concentration of various drugs (phenobarbital, amphetamines, morphine, and so forth), may be regarded as excellent reagents for immunocytochemistry. This clearly indicates that morphological evidence in toxicology, which had so far remained obscure, can be easily obtained by applying these antisera against various drugs. 相似文献
977.
J J Kuhlman R W Mayes B Levine R Jones G N Wagner M L Smith 《Journal of forensic sciences》1991,36(5):1572-1579
Chloroquine concentrations in blood and tissues were examined in overdose and non-overdose cases to determine appropriate ranges for interpretation. Twenty-nine literature overdose cases and 8 non-overdose literature cases were compared with this laboratory's findings. The results indicate significant postmortem redistribution of chloroquine. Combining this laboratory's results and the literature results indicates that using a liver concentration of 150 mg/kg as a cutoff between overdose and non-overdose concentrations properly identified 30 of the 34 published cases containing liver chloroquine and 19 of the 20 presented cases. 相似文献
978.
One December morning the naked bodies of two alcoholics were found on an open place in the center of the city of Essen. The phenomenon of paradoxical undressing due to vital hypothermia is described and the significant influence of alcohol on hypothermia and confusion in connection with hypothermia is pointed out. Compared to the results of other authors, external and internal signs of lethal hypothermia were analysed in a retrospective series of 30 cases (autopsy material in the region of Essen, investigation period from 1979-1989). 相似文献
979.
Mild hypothermia, induced by experimental immersion of ten subjects in cold water, distorted the decay curve of breath ethanol of intoxicated subjects by as much as 22% while not altering overall ethanol clearance rate. The results provide in vivo verification of the in vitro temperature correction factor of 6.8% X degrees C-1, and support previous recommendations that temperature monitoring be included in procedures for breath-ethanol testing. We recommend that mouth temperature be obtained before breath sampling to screen for abnormal body temperature and to allow for potential use of a temperature correction factor. This modification to existing analytical procedures would help to optimize the reliability of breath-ethanol analysis in predicting blood-ethanol concentration. 相似文献
980.
Theory based on sex role traditionalism predicts a more punishing decision for female than for male offenders, while theory based on chivalry (paternalism) predicts greater leniency by the courts for female offenders. This paper tests these two models using a large sample (36,680) of juvenile court referrals in metropolitan, urban, and rural locations spanning a nine-year period. Nonparametric analysis of covariance is used to control for differences in offense, previous contact with the court system, and other background variables. Evidence of gender bias in dispositions was found. The patterns of bias across time, location, offense committed, and previous referral to the court system supports the persistence of chivalry and a decline in sex role traditionalism in court decisions. Greater punishment for girls than boys was found only for repeat offenders committing more serious offenses. Even in those cases, girls were more likely to be taken out of the home environment by the courts through a custody transfer while boys were more likely to be sent to a lock-up facility. 相似文献