全文获取类型
收费全文 | 6499篇 |
免费 | 291篇 |
国内免费 | 1篇 |
专业分类
各国政治 | 373篇 |
工人农民 | 48篇 |
世界政治 | 941篇 |
外交国际关系 | 801篇 |
法律 | 3047篇 |
中国共产党 | 314篇 |
中国政治 | 597篇 |
政治理论 | 312篇 |
综合类 | 358篇 |
出版年
2023年 | 28篇 |
2022年 | 26篇 |
2021年 | 17篇 |
2020年 | 27篇 |
2019年 | 42篇 |
2018年 | 53篇 |
2016年 | 35篇 |
2015年 | 37篇 |
2014年 | 165篇 |
2013年 | 113篇 |
2012年 | 396篇 |
2011年 | 437篇 |
2010年 | 231篇 |
2009年 | 170篇 |
2008年 | 330篇 |
2007年 | 387篇 |
2006年 | 418篇 |
2005年 | 375篇 |
2004年 | 348篇 |
2003年 | 337篇 |
2002年 | 301篇 |
2001年 | 237篇 |
2000年 | 234篇 |
1999年 | 144篇 |
1998年 | 108篇 |
1997年 | 89篇 |
1996年 | 77篇 |
1995年 | 92篇 |
1994年 | 101篇 |
1993年 | 68篇 |
1992年 | 55篇 |
1991年 | 72篇 |
1990年 | 61篇 |
1989年 | 71篇 |
1988年 | 109篇 |
1987年 | 89篇 |
1986年 | 83篇 |
1985年 | 93篇 |
1984年 | 90篇 |
1983年 | 97篇 |
1982年 | 67篇 |
1981年 | 71篇 |
1980年 | 90篇 |
1979年 | 48篇 |
1977年 | 19篇 |
1964年 | 25篇 |
1962年 | 21篇 |
1961年 | 18篇 |
1959年 | 20篇 |
1957年 | 16篇 |
排序方式: 共有6791条查询结果,搜索用时 15 毫秒
971.
McMurtrie L 《Journal of law and medicine》2006,14(2):220-227
This article argues that liability for negligent medical treatment should be predicated upon a standard of care reflecting what is medically and scientifically reasonable. Legal science (jurisprudence) and medical science (evidence-based medicine) should be reconciled to improve patient care and outcomes. The use of antenatal corticosteroids in obstetrics during the 1990s illustrates how most jurisprudence for setting the standard of care for treatment is ill equipped to meet the fundamental aims of tort law. The proliferation of evidence-based medical practice provides a unique opportunity for the law to encourage best medical practice when setting the standard of care for treatment. It is argued that, eventually, the law should recognise clinical practice guidelines as the prima facie standard of care for treatment. This will provide legal certainty, appropriate medical practitioner accountability, and ultimately improve patient care and outcomes. 相似文献
972.
973.
974.
d'Arlach L Olson BD Jason LA Ferrari JR 《Journal of prevention & intervention in the community》2006,31(1-2):121-131
This study explored the sense of community among women (n = 21) and women with children (n = 30) living in Oxford Houses, with emphasis on how the presence of children might affect the household. Sense of community did not vary between participants with more or less than three months residence. Residents reported very high levels of satisfaction with the home, possibly because of a ceiling effect of little room for increases in their sense of community over time. Participants reported that they were getting along with the children in the home, that mothers could count on babysitting help, and that the children had a positive effect on the household and their own recovery process. This effect did not differ between mothers and non-mothers, suggesting that non-mothers might view the children in the home with a sense of responsibility and sensitivity comparable to that of the mothers. Implications are discussed. 相似文献
975.
976.
The authors report on a drug fatality of a 21-year-old man with a propofol (2,6-di-isopropylphenol) dependency. Propofol was detected in tissues and body fluids using SPME-GC/MS methods. The postmortem concentrations of propofol were 364 ng/ml in urine, 71 ng/ml in heart blood and 79 ng/ml in femoral blood. The drug addict had only an autodidactic medical knowledge, but had inserted himself a permanent cannula for intravenous injection of propofol several times a day. The injection material was bought via online auctions from eBay. The case illustrates how job-related drug dependencies become indistinct due to the free access to information and goods via the Internet. 相似文献
977.
In the last decade, computer-based systems for the comparison of microscopic firearms evidence have been the subject of considerable research work because of their expected capability of supporting the firearms examiner through the automated analysis of large amounts of evidence. The Integrated Ballistics Identification System, which is based on a two-dimensional representation of the specimen surface, has been widely adopted in forensic laboratories worldwide. More recently, some attempts to develop systems based on three-dimensional (3D) representations of the specimen surface have been made, both in the literature and as industrial products, such as BulletTRAX-3D, but fundamental limitations in achieving fully automated identification remain. This work analyzes the advantages and disadvantages of a 3D-based approach by proposing an approach and a prototype system for firearms evidence comparison that is based on the acquisition and analysis of the 3D surface topography of specimens, with particular reference to cartridge cases. The concept of 3D virtual comparison microscope is introduced, whose purpose is not to provide fully automated identification, but to show how the availability of 3D shape information can provide a whole new set of verification means, some of them being described and discussed in this work, specifically, visual enhancement tools and quantitative measurement of shape properties, for supporting, not replacing, the firearm examiner in reaching the final decision. 相似文献
978.
The population of the Asian elephant is being dramatically reduced due to poaching of the ivory from the male. As poaching occurs in remote forests, it often takes weeks or longer for it to be discovered and it is therefore often very difficult to determine the sex of the decomposed body. Data suggest that in the recent past, over 2000 male elephants have been poached in South India. We have developed a technique based on molecular markers to determine that the carcass is an elephant and that it is a male. Using DNA sequence information from Genbank, we have developed two primer pairs: one for the mitochondrial DNA (mtDNA) and the other for the sex-determining region of Y chromosome (SRY) gene of the Indian elephant. After PCR amplification of known elephant DNA, we found that the mtDNA was common in both males and females, whereas the SRY-specific amplicon was observed only in the male. 相似文献
979.
Jackowski C Bolliger S Aghayev E Christe A Kilchoer T Aebi B Périnat T Dirnhofer R Thali MJ 《Journal of forensic sciences》2006,51(5):1134-1137
Postmortem investigation is increasingly supported by computed tomography (CT) and magnetic resonance imaging, in which postmortem minimal invasive angiography has become important. The newly introduced approach using an aqueous contrast agent solution provided excellent vessel visualization but was suspected to possibly cause tissue edema artifacts in histological investigations. The aim of this study was to investigate on a porcine heart model whether it is possible to influence the contrast agent distribution within the soft tissue by changing its viscosity by dissolving the contrast agent in polyethylene glycol (PEG) as a matrix medium. High-resolution CT scans after injection showed that viscosities above c. 15 mPa s (65% PEG) prevented a contrast agent distribution within the capillary bed of the left ventricular myocardium. Thereby, the precondition of edema artifacts could be reduced. Its minimal invasive application on human corpses needs to be further adapted as the flow resistance is expected to differ between different tissues. 相似文献
980.