全文获取类型
收费全文 | 18972篇 |
免费 | 292篇 |
专业分类
各国政治 | 617篇 |
工人农民 | 1454篇 |
世界政治 | 928篇 |
外交国际关系 | 668篇 |
法律 | 11352篇 |
中国政治 | 72篇 |
政治理论 | 4085篇 |
综合类 | 88篇 |
出版年
2020年 | 109篇 |
2019年 | 163篇 |
2018年 | 1434篇 |
2017年 | 1385篇 |
2016年 | 1222篇 |
2015年 | 225篇 |
2014年 | 202篇 |
2013年 | 1018篇 |
2012年 | 401篇 |
2011年 | 1149篇 |
2010年 | 1188篇 |
2009年 | 831篇 |
2008年 | 1000篇 |
2007年 | 976篇 |
2006年 | 296篇 |
2005年 | 322篇 |
2004年 | 425篇 |
2003年 | 396篇 |
2002年 | 276篇 |
2001年 | 431篇 |
2000年 | 383篇 |
1999年 | 301篇 |
1998年 | 174篇 |
1997年 | 139篇 |
1996年 | 162篇 |
1995年 | 163篇 |
1994年 | 160篇 |
1993年 | 145篇 |
1992年 | 240篇 |
1991年 | 255篇 |
1990年 | 246篇 |
1989年 | 250篇 |
1988年 | 228篇 |
1987年 | 226篇 |
1986年 | 263篇 |
1985年 | 261篇 |
1984年 | 238篇 |
1983年 | 222篇 |
1982年 | 156篇 |
1981年 | 135篇 |
1980年 | 114篇 |
1979年 | 160篇 |
1978年 | 96篇 |
1977年 | 121篇 |
1976年 | 95篇 |
1975年 | 71篇 |
1974年 | 90篇 |
1973年 | 86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
921.
922.
Crystallographic analysis of the cerebrospinal fluid (CSF) was carried out in 18 cases of death from coronary disease and 19 cases of death from ethanol poisoning. The crystallograms were evaluated visually and by the stereoscopic picture. Specific features of the CSF crystal colonies growth in subjects dead from the above conditions are determined. 相似文献
923.
Trivedi R Chattopadhyay P Kashyap VK 《The American journal of forensic medicine and pathology》2002,23(2):191-196
A new method for better recovery of DNA suitable for amplification of hypervariable loci from fragments of teeth, consisting of two steps-scraping and aspiration, and extensive decalcification-is reported. Higher yields of high molecular weight DNA were obtained from the root, pulp, and crown of all kinds of 120 teeth, irrespective of gender, age, and source of teeth. HLA DQA1, 5 poly markers (LDLR, GYPA, HBGG, D7S8, and Gc), and other 12 short tandem repeat loci (HPRTB, F13B, LPL, D13S317, D7S820, D5S818, D21S11, D18S51, FGA, D8S1179, D3S1358, and vWA) could be successfully amplified and typed from recovered DNA. 相似文献
924.
Oliver WR Baker AM Powell JD Cotone CM Meeker J 《The American journal of forensic medicine and pathology》2002,23(3):252-256
An ordnance-disposal expert was killed while disposing of a cache of explosives. The likely position of the body was reconstructed by modeling the explosion as an omnidirectional emission of particles from a model of the explosion site and noting the distribution of particles on a model of a human. The applications and limitations of this method in reconstructing the events and correlation with the injuries noted at autopsy are discussed. 相似文献
925.
It is argued that American courts may be routinely admitting evidence with little to no probative value and great potential for prejudicial impact. This may be particularly likely with regard to what is essentially intuitive profiling or stereotype related evidence, defined herein as evidence suggesting that the defendant (or other party), or his (her) behavior, fits intuitive profiles (or stereotypes) of the type of person likely to commit the crime or behavior in question. In other words, intuitive profiling evidence is admitted to postdict behavior. Formal empirically based profiling evidence (testimony regarding the fit of a defendant's characteristics or behaviors to formal or scientific profiles of the typical perpetrator of the crime in question for use to prove guilt is inadmissible in American courts. However, we suggest that everyday use of informal intuitive profiles underlies both judicial determinations of probative value diagnosticity, and thus admissibility, of evidence, and jurors' use of the evidence in determining guilt. Demonstrations of the use of base rate information to evaluate the probative value of such intuitive profiling evidence both as evidence of guilt and as evidence of innocence are provided. Demonstrations of both how to evaluate the actual probative value of evidence (when all necessary values are known), and the theoretical limit of its probative value (in circumstances where some values are not known) are provided. It is argued that such evaluations may provide the basis for (1) support of motions to either admit or to exclude evidence, (2) testimony to the jury to help them weigh or interpret evidence, (3) exculpatory profiling (profiling evidence of innocence), (4) pretrial research to establish probative versus prejudicial value of evidence, and (5) sufficiency analyses to determine maximum likelihood of guilt, given multiple items of evidence. Among these, the first two are considered most important, as it can be demonstrated that many profiling characteristics currently admitted in trial (such as evidence of battery to support a murder charge) are not probative of guilt. 相似文献
926.
Frutos LR 《The American journal of forensic medicine and pathology》2002,23(3):284-288
The clavicle has been described as a useful bone for the metric determination of sex of human skeletal remains in a contemporary, predominantly white, North American forensic sample. In this article, measurements of clavicle and scapula are provided for a contemporary Guatemalan rural indigenous sample of forensic origin. Maximum length and circumference at midshaft of the clavicle, and height and width of the glenoid fossa of the scapula, were measured in 35 female and 62 male clavicles, and in 38 female and 65 male scapulae. Discriminant function analysis was used to study sexual dimorphism in this population with a classification purpose. Leave-one-out method (jackknife) matrices produced classification success rates ranging from 85.6% to 94.8%. A comparison with the North American forensic sample showed low percentages of correctly sexed Guatemalan male clavicles, ranging from 29.4% to 54.9%. The choice of an appropriate standard for the metric determination of sex is a crucial step in forensic anthropology. 相似文献
927.
Sukhai A Harris C Moorad RG Dada MA 《The American journal of forensic medicine and pathology》2002,23(3):295-298
Self-immolation is an uncommon method of suicide, and its occurrence in South Africa is thus far unknown. This study aimed to determine the prevalence of self-immolation deaths and to establish a profile of these cases and the circumstances under which this condition occurs. A 5-year (1996-2000) retrospective review at a mortuary in Durban, South Africa, was conducted. Data were obtained from the Department of Forensic Medicine, the Medical Research Council's National Injury Mortality Surveillance System, and police and hospital records. During the study period, there were 12339 nonnatural deaths, of which 696 (5.6%) were suicides. Self-immolation accounted for 69 (0.6%) of all nonnatural deaths and 69 (9.9%) of all suicides. The subjects had a mean age of 31.2 years and were predominantly female (76.8%) and black (81.2%). The mean burn surface area was 63.3%, and the mean injury severity score was 36.9. Accelerant use was documented in 53 (76.8%) of cases, and paraffin was preferred. All cases occurred indoors. The proportion of suicides due to self-immolation in our study is excessive when compared with international studies that report figures between 0.9% and 2.2% of suicides. Additional studies are necessary to further elucidate the reasons for this discrepancy. 相似文献
928.
Childhood sporting deaths 总被引:1,自引:0,他引:1
Byard RW James RA Gilbert JD 《The American journal of forensic medicine and pathology》2002,23(4):364-367
929.
The authors describe three accidental deaths resulting from occupational hazards involving environmental gas alterations. One involved the displacement of oxygen caused by leakage of liquid nitrogen during the installation of a magnetic resonance imaging system. Two involved elevated environmental carbon dioxide concentrations: dry ice sublimation in a walk-in refrigerator in a research laboratory, and activation of a carbon dioxide fire alarm-extinguisher system by a woman locked in a bank vault. The autopsy findings, scene investigations, and certifications of these deaths, as related to the mechanisms of death, are discussed. 相似文献
930.
Hertzfeld HR 《The Journal of Technology Transfer》2002,27(4):311-320
Since 1958 NASA has invested approximately $3.7 billion in life sciences R&D in the support of the successful human space flight program. There are numerous studies documenting the spin-off technologies that can be traced to NASA research and development activities. Most of these studies describe the technologies and their uses; however only a few measure the economic impact of the spin-offs and most of these are benefit/cost studies that tend to overstate benefits or underestimate costs. This study takes a different approach, measuring only economic impacts to the companies that developed successful spin-off products from NASA life sciences investments. A personal interview was conducted with each company and the benefits are conservatively estimated as the value-added by the NASA technology to the company's output and the amount of additional private R&D stimulated by the NASA R&D.This pilot study of fifteen companies, using a very conservative measurement technique, found a large return to companies that have successfully commercialized NASA life sciences spin-off products. Value-added benefits totaled over $3.7 billion in life sciences R&D in the support of the successful human space flight program. There are numerous studies documenting the spin-off technologies that can be traced to NASA research and development activities. Most of these studies describe the technologies and their uses; however only a few measure the economic impact of the spin-offs and most of these are benefit/cost studies that tend to overstate benefits or underestimate costs. This study takes a different approach, measuring only economic impacts to the companies that developed successful spin-off products from NASA life sciences investments. A personal interview was conducted with each company and the benefits are conservatively estimated as the value-added by the NASA technology to the company's output and the amount of additional private R&D stimulated by the NASA R&D.This pilot study of fifteen companies, using a very conservative measurement technique, found a large return to companies that have successfully commercialized NASA life sciences spin-off products. Value-added benefits totaled over 1.5 billion and a NASA R&D total investment in these 15 technologies of 64 million was found to stimulate an additional64 million was found to stimulate an additional 200 million in private R&D. 相似文献