全文获取类型
收费全文 | 2271篇 |
免费 | 79篇 |
专业分类
各国政治 | 116篇 |
工人农民 | 123篇 |
世界政治 | 156篇 |
外交国际关系 | 118篇 |
法律 | 1417篇 |
中国共产党 | 1篇 |
中国政治 | 39篇 |
政治理论 | 372篇 |
综合类 | 8篇 |
出版年
2023年 | 17篇 |
2022年 | 21篇 |
2021年 | 47篇 |
2020年 | 64篇 |
2019年 | 78篇 |
2018年 | 78篇 |
2017年 | 80篇 |
2016年 | 91篇 |
2015年 | 65篇 |
2014年 | 72篇 |
2013年 | 269篇 |
2012年 | 83篇 |
2011年 | 78篇 |
2010年 | 52篇 |
2009年 | 60篇 |
2008年 | 66篇 |
2007年 | 79篇 |
2006年 | 49篇 |
2005年 | 49篇 |
2004年 | 73篇 |
2003年 | 62篇 |
2002年 | 49篇 |
2001年 | 119篇 |
2000年 | 88篇 |
1999年 | 84篇 |
1998年 | 44篇 |
1997年 | 14篇 |
1996年 | 17篇 |
1995年 | 21篇 |
1994年 | 12篇 |
1993年 | 17篇 |
1992年 | 33篇 |
1991年 | 28篇 |
1990年 | 48篇 |
1989年 | 33篇 |
1988年 | 36篇 |
1987年 | 27篇 |
1986年 | 15篇 |
1985年 | 16篇 |
1984年 | 16篇 |
1983年 | 10篇 |
1982年 | 14篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 14篇 |
1978年 | 10篇 |
1977年 | 5篇 |
1971年 | 5篇 |
1970年 | 5篇 |
1969年 | 4篇 |
排序方式: 共有2350条查询结果,搜索用时 15 毫秒
141.
建立了生物检材中芬氟拉明的定性定量分析方法。体液及脏器组织经有机溶剂提取后 ,用GC/MS法进行药物筛选、定性 ,生物检材中的芬氟拉明浓度用4 -苯丁胺作内标、GC/NPD法测定。测得芬氟拉明中毒致死者的血液、尿液、肝等组织中浓度分别为7.8μg/ml、64.2μg/ml、31.3μg/g。并对尸体解剖所见及方法可行性进行讨论 相似文献
142.
143.
144.
145.
The public choice literature contains little formal analysis of the bureaucratic choice of production modes — public or private — of publicly funded services. An important question to be addressed is why some governmental bodies choose to provide a publicly funded service with publicly owned and operated production units whereas other governmental bodies contract with private firms to provide the same publicly funded service. This paper is the first formal attempt to remedy this gap in the literature. We develop a theoretical explanation of the government decision maker's choice between public and private production modes based on utility maximizing behavior. We then examine empirically this choice employing logit analysis. The empirical results, which include several tests for robustness, confirm our theoretical explanation. The results are significant and suggest that non-monetary constraints are an important factor affecting this choice of production modes and that monetary constraints are less influential. 相似文献
146.
Radioimmunoassay of alpha 1-fetoprotein(AFP) for medico-legal identification of fetal blood stains using a commercial kit is described. The AFP content in fetal blood stains on filter paper ranged from 21--320 ng/9 mm2. The protein was detected in stains of adult blood and retroplacental blood in only negligible amounts. Aging of the blood stains did not influence the values up to 1 month. The method is simple and sensitive enough for application to medico-legal-practice. 相似文献
147.
148.
149.
A few papers in the literature reported incident deaths by acute ketamine poisoning. In this paper, we report an unusual homicide caused by chronic ketamine poisoning. The victim was a 34-year old married woman with no previous medical history (except as reported herein) who died in her own home. The court investigation revealed that she was chronically poisoned by her husband over a period of about one year in an act of homicide. Determination of ketamine concentrations in autopsy specimens was carried out with gas-chromatography/mass spectrometry (GC-MS). The results showed that ketamine concentration was 21 microg/mL in gastric contents, 3.8 microg/mL in blood and 1.2 microg/mL in urine. The most striking forensic findings were cardiac muscle fibrosis and hyaline degeneration of small arteries in victim's heart, the pathological features of ketamine poisoning previous reported only in animal studies. 相似文献
150.
Latkoczy C Becker S Dücking M Günther D Hoogewerff JA Almirall JR Buscaglia J Dobney A Koons RD Montero S van der Peijl GJ Stoecklein WR Trejos T Watling JR Zdanowicz VS 《Journal of forensic sciences》2005,50(6):1327-1341
Forensic analysis of glass samples was performed in different laboratories within the NITE-CRIME (Natural Isotopes and Trace Elements in Criminalistics and Environmental Forensics) European Network, using a variety of Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) systems. The main objective of the interlaboratory tests was to cross-validate the different combinations of laser ablation systems with different ICP-MS instruments. A first study using widely available samples, such as the NIST SRM 610 and NIST SRM 612 reference glasses, led to deviations in the determined concentrations for trace elements amongst the laboratories up to 60%. Extensive discussion among the laboratories and the production of new glass reference standards (FGS 1 and FGS 2) established an improved analytical protocol, which was tested on a well-characterized float glass sample (FG 10-1 from the BKA Wiesbaden collection). Subsequently, interlaboratory tests produced improved results for nearly all elements with a deviation of < 10%, demonstrating that LA-ICP-MS can deliver absolute quantitative measurements on major, minor and trace elements in float glass samples for forensic and other purposes. 相似文献