首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1838篇
  免费   61篇
各国政治   154篇
工人农民   59篇
世界政治   95篇
外交国际关系   63篇
法律   1256篇
中国政治   9篇
政治理论   252篇
综合类   11篇
  2022年   12篇
  2020年   36篇
  2019年   37篇
  2018年   51篇
  2017年   69篇
  2016年   63篇
  2015年   30篇
  2014年   38篇
  2013年   215篇
  2012年   44篇
  2011年   63篇
  2010年   40篇
  2009年   41篇
  2008年   51篇
  2007年   51篇
  2006年   48篇
  2005年   52篇
  2004年   51篇
  2003年   59篇
  2002年   44篇
  2001年   64篇
  2000年   50篇
  1999年   48篇
  1998年   17篇
  1997年   14篇
  1996年   19篇
  1995年   12篇
  1994年   14篇
  1993年   12篇
  1992年   30篇
  1991年   32篇
  1990年   36篇
  1989年   38篇
  1988年   35篇
  1987年   25篇
  1986年   35篇
  1985年   26篇
  1984年   20篇
  1983年   16篇
  1982年   12篇
  1981年   18篇
  1980年   11篇
  1979年   19篇
  1978年   21篇
  1977年   16篇
  1971年   18篇
  1970年   17篇
  1969年   11篇
  1968年   17篇
  1967年   12篇
排序方式: 共有1899条查询结果,搜索用时 0 毫秒
991.
Massive pulmonary embolism in cancer patients can be due to detached thrombi or tumor. Pulmonary tumor embolism is often undiagnosed antemortem. We report a 52-year-old Chinese man admitted for management of hepatocellular carcinoma (HCC). Computerized tomography showed tumor involvement of hepatic vein and inferior vena cava. He died suddenly on the day of admission. At autopsy the main pulmonary arteries of both lungs were blocked by large tumor emboli, the immediate cause of death. Although rapid death in patients with HCC is usually caused by intraperitoneal hemorrhage from spontaneous rupture of tumor, massive pulmonary tumor embolism should also be considered in these patients, especially when antemortem evidence of hepatic vein and/or inferior vena cava invasion is present.  相似文献   
992.
In this paper, miniaturized achiral and chiral high-performance liquid chromatographic procedures for the determination of methamphetamine and amphetamine in human urine are described. After a simple pretreatment of human urine (i.e., 10 microL of urine or diluted urine were acidified and dried-up under N2 at room temperature) and fluorescence derivatization with 4-(4,5-diphenyl-1H-imidazol-2-yl)-benzoyl chloride under mild conditions (pH 9.0, 10 min at room temperature), the derivatives were isocratically separated on a semi-micro ODS column with Tris-HCl buffer (0.1 M, pH 7.0): acetonitrile (45 + 55 v/v) at a flow rate of 0.2 mL/min or their enantiomers were separated on a semi-micro OD-RH column with sodium hexafluorophosphate (0.3 M aq.): acetonitrile (44 + 56 v/v) at a flow rate of 0.1 mL/min as the mobile phase. Wide-ranged calibration curves were obtained with detection limits for the achiral and chiral analyses in the atto and femtomol levels, respectively, per injected volume. Satisfactory within- and between-day reproducibility data were obtained with both the methods with the highest relative standard deviation being 9.6%. The methods were applied to the determination of methamphetamine and amphetamine in human urine samples and the concentrations determined by the two methods were well correlated (r = 0.994).  相似文献   
993.
Postmortem investigation of lamotrigine concentrations   总被引:1,自引:0,他引:1  
Lamotrigine is a relatively new anticonvulsant. Therapeutic plasma concentrations generally range from 1 to 4 mg/L, although several studies have shown that good control of epilepsy has been achieved with concentrations reaching 10 mg/L generally, with little toxicity. In overdose, however, the drug has been linked to ECG changes that may suggest a possible arrythmogenic effect and hence cardiac toxicity. Lamotrigine has also been shown to cause encephalopathy and thus neurotoxicity. There is no information concerning postmortem lamotrigine concentrations and their interpretation. We describe lamotrigine concentrations in postmortem specimens including blood, liver, bile, vitreous humour, and urine from eight cases. A high performance liquid chromatography (HPLC) method is described with extraction procedures for the various tissues. Two possible groups were identified. The first being the "broader therapeutic" group with blood concentrations ranging from 0.9 to 7.2 mg/L and corresponding liver concentrations ranging from 16 to 36 mg/kg. The second being a "supratherapeutic" group with blood concentrations ranging from 20 to 39 mg/L and corresponding liver concentrations ranging from 53 to 350 mg/kg. Although none of the eight cases described were attributed to overdose by lamotrigine alone, the cause of death for one of the three cases in the "supratherapeutic" group was given as mixed drug toxicity. Cause of death for the remaining two cases in this group was reported as epilepsy. However, both these cases showed elevated concentrations of lamotrigine and both were co-medicated with valproic acid. Such co-administration has been shown in the literature to lead to elevated lamotrigine concentrations and a reduction in lamotrigine dose has been recommended. With such data, we highlight the importance of monitoring lamotrigine concentrations in cases co-medicated, particularly with valproic acid.  相似文献   
994.
Suicide attempts can be described to include all actions taken by an individual to end their life as a result of acute desperation. In parallel with the changes in the make-up of human societies both globally and in this country in recent years, suicide attempts are receiving attention in ever increasing proportions. The current study is aimed at investigating the psycho-socio-cultural factors that contribute to the known cases of suicide attempts. The study included 116 cases admitted to the Emergency Internal Medicine and Surgery Units of the University of Istanbul, Faculty of Medicine Hospital between 1 December 1998 and 31 May 1999. In only 47 cases, a 30-point questionnaire was used in several face-to-face interviews with the patients following the preparation of a clinical case study. In establishing the socio-demographic, socio-cultural and socio-economic attributes of each individual case, a range of contributing effective factors is questioned. Including the specific reasons for each suicide attempt, the emotional state of the individual prior to the suicide attempt, the type of suicide action chosen and reasons for this selection, immediate family structure, personal psychiatric antecedent, substance abuse. The results of our investigations are compared with the existing literature in a multi-faceted discussion.  相似文献   
995.
996.
997.
998.
999.
1000.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号