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   512篇
  免费   29篇
  国内免费   96篇
耳鼻咽喉   3篇
儿科学   12篇
妇产科学   7篇
基础医学   82篇
口腔科学   13篇
临床医学   77篇
内科学   122篇
皮肤病学   12篇
神经病学   27篇
特种医学   30篇
外科学   61篇
综合类   41篇
预防医学   29篇
眼科学   7篇
药学   93篇
中国医学   9篇
肿瘤学   12篇
  2021年   8篇
  2020年   4篇
  2019年   3篇
  2018年   12篇
  2017年   12篇
  2016年   9篇
  2015年   14篇
  2014年   14篇
  2013年   15篇
  2012年   24篇
  2011年   20篇
  2010年   18篇
  2009年   20篇
  2008年   19篇
  2007年   67篇
  2006年   27篇
  2005年   28篇
  2004年   12篇
  2003年   15篇
  2002年   23篇
  2001年   19篇
  2000年   39篇
  1999年   20篇
  1998年   11篇
  1997年   9篇
  1996年   17篇
  1995年   10篇
  1994年   15篇
  1993年   6篇
  1992年   16篇
  1991年   17篇
  1990年   12篇
  1989年   7篇
  1988年   16篇
  1987年   5篇
  1986年   3篇
  1984年   3篇
  1983年   2篇
  1981年   3篇
  1980年   2篇
  1978年   3篇
  1977年   2篇
  1975年   2篇
  1974年   2篇
  1973年   3篇
  1972年   5篇
  1971年   6篇
  1970年   2篇
  1969年   3篇
  1965年   2篇
排序方式: 共有637条查询结果,搜索用时 15 毫秒
1.
For the treatment of intraabdominal infection, single-agent antimicrobial regimens such as β-lactams with good antianaerobic activity are frequent alternatives to combination regimens such as aminoglycosides or aztreonam plus an antianaerobic agent such as clindamycin or metronidazole. The major issues in selecting a regimen are relative efficacy, potential for adverse drug effects, and cost. Single agents are clearly equivalent to combinations in preventing infectious complications after penetrating abdominal trauma and in treating established intraabdominal infections of mild to moderate severity or in relatively low-risk patients. A few trials demonstrated their equivalency in patients at high risk of mortality, although experience is limited. Single-agent regimens may reduce the risks of adverse drug effects compared with combination regimens, but they are not always less expensive.  相似文献   
2.
合成了18个O,O′-二烷基-O″-(5-取代-3-苯并噻吩乙腈肟)磷酸酯及硫代磷酸酯类化合物(Ⅰ1~18)。初步杀螺试验结果表明,其中5个化合物,即Ⅰ2,3,7,11,12有明显的杀螺增效作用。  相似文献   
3.
本文采用丹酰氯聚酰胺薄层分析法研究了65名3~7岁健康儿童的血浆游离氨基酸,研究其与体格生长的关系.结果表明:赖氨酸,甘氨酸,羟脯氨酸,与年龄别身高、体重和身高别体重百分位成正相关.并有显著意义.异亮氨酸.赖氨酸.甘氨酸在营养优组中显著高于差组.提示血浆游离氨基酸对健康学龄前儿童的体格生长发挥重要的生理作用.  相似文献   
4.
We operated 5 patients with the Budd-Chiari syndrome or veno-occlusive disease between 1984 and 1989 (2 porto-caval shunts, one Warren distal spleno-renal shunt, one meso-atrial shunt and one Le Veen peritoneo-jugular shunt). As liver transplantation is now part of the therapeutic armamentarium for these conditions, this paper reviews retrospectively the indications for surgery in these 5 patients.  相似文献   
5.
6.
目的 探讨新生儿C6PD缺陷病和晚发性维生素K缺乏症的危害与预防措施。方法 回顾分析1995-2000年儿内科住院的1周-2月(不含2月)的婴儿3104例次,其中病死56例。结果 1周-2月的小婴儿占住院患儿的19.34%,其中新生儿G6PD缺陷病239例,占7.70%;晚发性维生素K缺乏症92例,占2.96%。死因的第2、3位分别是晚发性维生素K缺乏症(13例,占23.21%)和新生儿C6PD缺陷病(12例,占21.43%),两者的病死率分别为14.13%和5.02%,极显著高于(x^2=17.59,P<0.01)或相近于(x^2=0.88,P>0.05)肺炎的3.57%。新生儿G6PD缺陷病合并感染占38.49%、低氧血症占23.35%、低血糖占19.25%、酸中毒占15.90%,继发胆红素脑病占13.81%。晚发性维生素K缺乏症出现抽搐占90.22%、胃肠、注射部位出血占60.89%;CT证实颅内出血占98.91%。结论 1周-2月的小婴儿约占住院患儿的两成,新生儿G6PD缺陷病和晚发性维生素K缺乏症的病死率均很高,两者是除肺炎外最主要的死因。提议制定并推广预防这2种疾病的常规措施,并参照国内外相应的现状拟出其具体内容。  相似文献   
7.
H Perschak  M Cuénod 《Neuroscience》1990,35(2):283-287
The release of endogenous glutamate and aspartate from corticostriate neurons in the anaesthetized rat was investigated. Efflux of glutamate, aspartate and leucine in push-pull cannula perfusates of the striatum was measured in 1 min fractions collected before, during and after a 4 min stimulation period of ipsilateral frontal cortex. Efflux of the putative excitatory amino acid transmitters, glutamate and aspartate, determined during the first minute of stimulation, was significantly elevated above prestimulation resting level (by 167% and 316%, respectively), while efflux of leucine, a non-transmitter amino acid, remained unchanged. Efflux of glutamate and aspartate during the last 3 min of stimulation dropped rapidly, indicating the activation of a regulatory mechanism, presumably re-uptake. The data further support the hypothesis that glutamate and/or aspartate act as transmitters or are metabolites of transmitters in the corticostriate pathway.  相似文献   
8.
9.
Identification of quinolinic acid in rat and human brain tissue   总被引:20,自引:0,他引:20  
An analytical technique for the determination of the excitotoxic compound quinolinic acid (2,3-pyridine dicarboxylic acid) in brain tissue has been developed. Following sample prepurification by ion exchange and high pressure liquid chromatography, quinolinic acid is converted to the dihexafluoroisopropyl ester and the derivative is analyzed by mass fragmentography. Using the present technique quinolinic acid has been identified in both rat and human brain tissue.  相似文献   
10.
Objective To detect new mutations among 29 glucose-6-phosphate dehydrogenase (G6PD) deficient individuals from Yunnan province. Methods The nitroblue tetrazolium (NBT) method was used to screen G6PD deficient individuals. Mutation was identified by single strand conformation polymorphism (SSCP), amplification created restriction site (ACRS), amplification refractory mutation system (ARMS) and DNA sequencing. Results Among 29 cases, 18 cases of G1388A, 1 case of C1004A, and 1 case of G1381A were identified. Nine cases remained to be defined. The G1381A mutation is a novel mis-sense mutation, with a substitution of threonine for alanine (A461T). The resultant G6PD had reduced enzymatic activity. In addition, G1381A caused a restriction site of Stu I to disappear, providing a rapid method for the detection of this mutation. Conclusion A novel mis-sense mutation G1381A was found. This mutation results in a substitution of threonine for alanine, producing enzyme with reduced activity. The loss of the Stu I restriction site offers a rapid method for the detection of this mutation.  相似文献   
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