全文获取类型
收费全文 | 2609篇 |
免费 | 41篇 |
专业分类
各国政治 | 126篇 |
工人农民 | 62篇 |
世界政治 | 152篇 |
外交国际关系 | 67篇 |
法律 | 1919篇 |
中国政治 | 21篇 |
政治理论 | 286篇 |
综合类 | 17篇 |
出版年
2020年 | 30篇 |
2019年 | 22篇 |
2018年 | 22篇 |
2017年 | 34篇 |
2016年 | 40篇 |
2015年 | 23篇 |
2014年 | 38篇 |
2013年 | 187篇 |
2012年 | 60篇 |
2011年 | 68篇 |
2010年 | 37篇 |
2009年 | 35篇 |
2008年 | 56篇 |
2007年 | 71篇 |
2006年 | 71篇 |
2005年 | 74篇 |
2004年 | 72篇 |
2003年 | 71篇 |
2002年 | 70篇 |
2001年 | 156篇 |
2000年 | 123篇 |
1999年 | 76篇 |
1998年 | 26篇 |
1995年 | 18篇 |
1994年 | 22篇 |
1993年 | 21篇 |
1992年 | 63篇 |
1991年 | 69篇 |
1990年 | 61篇 |
1989年 | 84篇 |
1988年 | 83篇 |
1987年 | 72篇 |
1986年 | 76篇 |
1985年 | 65篇 |
1984年 | 35篇 |
1983年 | 41篇 |
1982年 | 19篇 |
1981年 | 30篇 |
1979年 | 28篇 |
1978年 | 21篇 |
1977年 | 27篇 |
1976年 | 19篇 |
1975年 | 31篇 |
1974年 | 30篇 |
1973年 | 31篇 |
1972年 | 32篇 |
1971年 | 24篇 |
1970年 | 20篇 |
1969年 | 24篇 |
1968年 | 20篇 |
排序方式: 共有2650条查询结果,搜索用时 7 毫秒
991.
992.
I Root 《The American journal of forensic medicine and pathology》1992,13(1):85-87
The problem of evaluating injury in childhood as to causation--accidental, inflicted or other--is compounded by conflicting literature. The child presenting with head injury following a short distance fall should be a source of alarm. Some of the key thoughts in the literature are evaluated with presentation of some additional observations, in an attempt to sort out some apparent conflicts. 相似文献
993.
994.
995.
996.
Despite their political prominence, cabinet reshuffles have not attracted a great deal of scholarly attention. We provide a theory of cabinet reshuffles that emphasizes both systematic and time‐varying causes. In particular, we argue that prime ministers employ cabinet reshuffles to retain power in the face of both intraparty and electoral challenges to their leadership. We use repeated‐events duration models to examine the timing of cabinet reshuffles in Australia, Canada, Ireland, New Zealand, and the United Kingdom in the period 1960–2001, and find support for several of our hypotheses. 相似文献
997.
998.
N B Wu Chen M I Schaffer R L Lin M L Kurland E R Donoghue R J Stein 《Journal of forensic sciences》1983,28(2):398-403
A general toxicology unknown case is presented to demonstrate our systematic approach. A 20-year-old male was found dead with multiple suicide notes. Overdose was suspected but substances were not known. Blood alcohol was negative. Urine was analyzed by enzyme-multiplied immunoassay technique and was negative for all drugs assayed. Urine was then extracted with ethyl acetate:hexane (1:1) at pH 10 and back-extracted into 1.0N sulfuric acid. The acidic layer was adjusted to pH 10, and re-extracted with ethyl acetate:hexane (1:1). The residue was analyzed by gas chromatography (GC) on a 3% OV-101 column. It was found to be negative for all commonly screened substances. However, several unknown peaks were observed. Electron impact mass spectra of these unknown peaks were obtained and searched for in our computer library of more than 25000 mass spectra. These unknown peaks were identified as doxylamine and pyrilamine by gas chromatography/mass spectrometry. The base peak and molecular ion for pyrilamine were at m/z 121 and 285, respectively. The base peak for doxylamine was at m/z 58. No molecular ion was observed for doxylamine. Both doxylamine and pyrilamine are antihistamines, but are promoted and used in the management of insomnia. Quantitation was performed on a GC using dexbrompheniramine as an internal standard. Blood concentrations for doxylamine and pyrilamine were 0.7 and 7.0 mg/L, respectively. Concentrations in other tissues were determined. Death was caused by combined doxylamine and pyrilamine intoxication; the manner of death was suicide. 相似文献
999.
1000.