全文获取类型
收费全文 | 4647篇 |
免费 | 186篇 |
专业分类
各国政治 | 209篇 |
工人农民 | 211篇 |
世界政治 | 311篇 |
外交国际关系 | 170篇 |
法律 | 3092篇 |
中国共产党 | 1篇 |
中国政治 | 41篇 |
政治理论 | 781篇 |
综合类 | 17篇 |
出版年
2023年 | 25篇 |
2021年 | 36篇 |
2020年 | 81篇 |
2019年 | 89篇 |
2018年 | 125篇 |
2017年 | 147篇 |
2016年 | 138篇 |
2015年 | 97篇 |
2014年 | 126篇 |
2013年 | 438篇 |
2012年 | 118篇 |
2011年 | 151篇 |
2010年 | 113篇 |
2009年 | 121篇 |
2008年 | 135篇 |
2007年 | 114篇 |
2006年 | 130篇 |
2005年 | 119篇 |
2004年 | 123篇 |
2003年 | 129篇 |
2002年 | 119篇 |
2001年 | 196篇 |
2000年 | 143篇 |
1999年 | 108篇 |
1998年 | 45篇 |
1997年 | 54篇 |
1996年 | 44篇 |
1995年 | 59篇 |
1994年 | 47篇 |
1993年 | 59篇 |
1992年 | 85篇 |
1991年 | 91篇 |
1990年 | 79篇 |
1989年 | 65篇 |
1988年 | 86篇 |
1987年 | 87篇 |
1986年 | 99篇 |
1985年 | 110篇 |
1984年 | 88篇 |
1983年 | 82篇 |
1982年 | 38篇 |
1981年 | 36篇 |
1979年 | 35篇 |
1978年 | 33篇 |
1975年 | 31篇 |
1974年 | 45篇 |
1972年 | 27篇 |
1971年 | 31篇 |
1970年 | 30篇 |
1968年 | 32篇 |
排序方式: 共有4833条查询结果,搜索用时 31 毫秒
991.
Sixteen deaths associated with the use of the Taser were examined. All involved young males who had a history of abuse of controlled substances; all but three were under the influence of cocaine, phencyclidine [phenylcyclohexylpiperidine (PCP)], or amphetamine. All were behaving in a bizarre or unusual fashion which necessitated calling the police. The cause of death was an overdose of drugs in eleven, gunshot wounds in three, heart disease and Taser shock in one, and an undetermined cause in one. All were considered to be under the influence of PCP by the police at the time of the incident. All were unarmed, which was the reason a Taser was used instead of a more lethal weapon. The conclusion reached after evaluation of these cases is that the Taser in and of itself does not cause death, although it may have contributed to death in one case. 相似文献
992.
993.
994.
995.
Gas chromatographic/mass spectrometric analysis of morphine and codeine in human urine of poppy seed eaters 总被引:1,自引:0,他引:1
H N elSohly D F Stanford A B Jones M A elSohly H Snyder C Pedersen 《Journal of forensic sciences》1988,33(2):347-356
In this study, poppy seeds were examined for a natural constituent that might serve as a maker for the seeds' ingestion as opposed to opiate abuse. Thebaine was selected as possible marker, since it was found to be a component of all poppy seeds examined and was not a natural component of different heroin samples. During the course of this investigation, a new extraction and cleanup procedure was developed for the gas chromatographic/nitrogen phosphorus detection (GC/NPD) and gas chromatographic/mass spectrometric (GC/MS) analysis of morphine and codeine in urine. A linear response, over a concentration range of 25 to 600 ng/mL, was obtained for codeine and morphine (r = 0.9982 and 0.9947, respectively). The minimum detectable level (LOD) and limit of quantitation (LOQ) for morphine were 10 and 30 ng/mL, respectively; whereas LOD and LOQ for codeine were 2 and 8 ng/mL, respectively. The coefficients of variance (CV, n = 6) for morphine and codeine analyses at the 100-ng/mL level were 13.3 and 4.6%, respectively. This procedure was used for the analysis of urine samples from five poppy seed eaters who each ingested 200 g of poppy seed cake. Results indicated that significant amounts of morphine and codeine are excreted in urine and that in all subjects, at least at one point in time, the apparent morphine concentration as determined by radioimmunoassay (RIA) analysis exceeded the cutoff value (300 ng/mL) established for screening. Thebaine was not detected in urine specimens collected following poppy seeds ingestion and thus could not be used as a marker. 相似文献
996.
Yellow oleander poisoning--a study of 170 cases 总被引:1,自引:0,他引:1
Yellow oleander or Thevetia peruviana is a very common plant in the North of Sri Lanka. Ever since the fact that the fruits and kernel are poisonous was published in the Newspapers, many cases of poisoning due to Thevetia occurred. 170 cases of Thevetia poisoning admitted to the Teaching Hospital, Jaffna in the North of Sri Lanka are studied by the authors. The mortality, morbidity, age distribution, presenting symptoms and clinical findings are analysed. The action of the cardiac glycoside in Thevetia is clearly demonstrated in this study. 相似文献
997.
998.
999.
Two cases of acute intoxication of buflomedil hydrochloride are reported. The analysis of this compound was performed by an Extrelut extraction followed by a gas chromatographic-mass spectrometric determination. Analytical parameters of linearity, reproducibility and specificity were satisfactory. 相似文献
1000.