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   14480篇
  免费   1057篇
  国内免费   453篇
耳鼻咽喉   181篇
儿科学   454篇
妇产科学   221篇
基础医学   1675篇
口腔科学   308篇
临床医学   1485篇
内科学   3013篇
皮肤病学   278篇
神经病学   932篇
特种医学   471篇
外国民族医学   2篇
外科学   1481篇
综合类   1257篇
一般理论   2篇
预防医学   1111篇
眼科学   497篇
药学   1167篇
  7篇
中国医学   422篇
肿瘤学   1026篇
  2024年   19篇
  2023年   146篇
  2022年   273篇
  2021年   537篇
  2020年   361篇
  2019年   409篇
  2018年   567篇
  2017年   430篇
  2016年   396篇
  2015年   539篇
  2014年   638篇
  2013年   720篇
  2012年   1050篇
  2011年   1130篇
  2010年   668篇
  2009年   463篇
  2008年   769篇
  2007年   791篇
  2006年   678篇
  2005年   720篇
  2004年   624篇
  2003年   603篇
  2002年   573篇
  2001年   467篇
  2000年   504篇
  1999年   400篇
  1998年   118篇
  1997年   97篇
  1996年   104篇
  1995年   92篇
  1994年   56篇
  1993年   51篇
  1992年   144篇
  1991年   119篇
  1990年   102篇
  1989年   110篇
  1988年   91篇
  1987年   75篇
  1986年   66篇
  1985年   50篇
  1984年   38篇
  1983年   23篇
  1982年   13篇
  1981年   9篇
  1980年   11篇
  1979年   14篇
  1977年   12篇
  1973年   9篇
  1970年   9篇
  1965年   8篇
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
31.
Alginates are the most employed biomaterials for cell encapsulation due to their abundance, easy gelling properties and apparent biocompatibility. However, as natural polymers different impurities including endotoxins, proteins and polyphenols can be found in their composition. Several purification protocols as well as different batteries of assays to prove the biocompatibility of the alginates in vitro have been recently developed. However, little is known about how the use of alginates with different purity grade may affect the host immune response after their implantation in vivo. The present paper investigates the long-term functionality and biocompatibility of murine erythropoietin (EPO) secreting C2C12 cells entrapped in microcapsules elaborated with alginates with different properties (purity, composition and viscosity). Results showed that independently of the alginate type employed, the animals presented elevated hematocrit levels until day 130, remaining at values between 70-87%. However, histological analysis of the explanted devices showed higher overgrowth around non-biomedical grade alginate microcapsules which could be directly related with higher impurity content of this type of alginate. Although EPO delivery may be limited by the formation of a fibrotic layer around non-biomedical grade alginate microcapsules, the high EPO secretion of the encapsulated cells together with the pharmacodynamic behaviour and the angiogenic and immune-modulatory properties of EPO result in no direct correlation between the biocompatibility of the alginate and the therapeutic response obtained.  相似文献   
32.
OBJECTIVE: To investigate the factors responsible for Pseudomonas aeruginosa nosocomial cross-infection in the intensive care unit (ICU) and provide effective measure for the prevention and management. METHODS: The homology of 7 Pseudomonas aeruginosa strains isolated from the patients in the ICU and the environment was examined by biological, serological, drug-resistance and plasmid analysis. RESULTS: The results of serological and plasmid analyses had good consistency, which demonstrated that the 7 Pseudomonas aeruginosa strains originated from solution in the oxygen humidifier, with uniform serological and plasmid type, and belonged to the same clone with cross-infection by contact between the patients or nursing staff and the objects in the ICU. CONCLUSION: Serological and plasmid analyses are more practical for identifying the sources of Pseudomonas aeruginosa cross-infection, which can be prevented by strict disinfection of the instrument and supervision of the nursing staff in the ICU.  相似文献   
33.
耳源性脑疝25例,抢救成功者19例。采用单纯脑脓肿穿刺抽脓抢救脑疝6例,仅1例成功;开颅减压术抢救脑疝20例,18例抢救成功。本组临床实践和文献报道都说明耳源性脑疝一旦发生应即刻行开颅减压术,能卓有成效地抢救生命  相似文献   
34.
为探讨构效关系,合成了1-对氟苯基-6-氟-1,4-二氢-4-氧-7-(1-哌嗪)噌啉-3-羧酸及其喹啉、萘啶、吡啶[2,3-C]哒嗪环系类似物16个。测定了对大肠杆菌的MIC。用Hückel分子轨道理论(HMO)方法计算了四个母体环上电子密度。结果表明:环中氮的位置对药效团——3位羧基和4位羰基氧原子上电子密度的影响较大而影响其抗菌活性。喹啉、萘啶两环系的3位羧基和4位羰基氧原子上的电子密度较高,其体外抗菌活性较高;而噌啉及吡啶[2,3-C]哒嗪两环系的电子密度较低,其体外抗菌活性较低甚至消失。  相似文献   
35.
Over a 6-year period (1982 to 1988), 36 episodes of septic arthritis were diagnosed in 35 heroin addicts from Barcelona, Spain. Thirty (86%) were men and five (14%) were women, with a mean age of 24 years (range, 14 to 39). Twenty-nine episodes (80%) were monoarticular and seven (20%) were oligoarticular. The sacroiliac (16 cases), sternoclavicular (8), hip (5), and shoulder (4) joints were most frequently infected. Staphylococcus aureus and Pseudomonas aeruginosa were the etiological agents in 75% and 11% of episodes, respectively. Response to antibiotic treatment was good in 32 cases (90%), eight patients needed surgical drainage, and none died. We conclude that septic arthritis in heroin addicts localizes predominantly in axial joints. In our geographic area, infection with S aureus is more frequent than with gram-negative rods such as P aeruginosa or Serratia marcescens, which are most frequently found in reports from the United States.  相似文献   
36.
Two cases are presented in which conventional approaches did not permit dilation of and stent placement in obstructed ureters. In patients with iatrogenic ureteral laceration or rigid ureteral kinking, direct percutaneous translumbar puncture may provide a safe alternative. The authors' technique is described.  相似文献   
37.
白色念珠菌感染的分子生物学诊断研究进展   总被引:1,自引:0,他引:1  
综述了白色念珠菌感染的分子生物学诊断研究进展,包括核型分析,限制性片段长度多态性分析,特异的DNA探针及PCR等方法。  相似文献   
38.
We evaluated the occurrence of REM sleep behaviour disorder (RBD) and vocal cord abductor paralysis (VCAP) in a group of 9 Machado-Joseph disease (MJD) patients. RBD was diagnosed by clinical history plus audiovisual polysomnography in 4 men and 1 woman (55%). While dreaming, 4 fell out of the bed and the other injured his arms. Laryngoscopy detected bilateral VCAP in 1 patient with stridor who required emergency tracheotomy, and partial vocal cord abductor restriction in 2. RBD and VCAP are two potentially injurious conditions that should be considered part of the clinical spectrum of MJD.  相似文献   
39.
为探讨曲格列酮(troglitazone,TGZ)对人卵巢颗粒细胞芳香化酶(P450arom)活性的调节作用,以不同剂量的TGZ和(或)维甲酸类X受体(RXR)激动剂(LG100268,LG)处理来源于体外受精患者的卵巢颗粒细胞24h,然后测定细胞的芳香化酶活性和P450arom mRNA水平。结果发现,TGZ处理颗粒细胞24h可引起剂量依赖性的芳香化酶活性下降;LG单独作用可以抑制芳香化酶活性,但与TGZ合用对芳香化酶的抑制作用更明显;RT-PCR结果显示,随着芳香化酶活性的下降,P450arom mRNA表达水平也降低。表明TGZ可能是通过过氧化物酶体增殖物激活受体γ(PPARγ):RXR异二聚体组成的核受体系统直接抑制卵巢颗粒细胞芳香化酶活性。  相似文献   
40.
应用了A、B、C法7种单克隆抗体进行免疫组化染色,检测南京地区23例成人非何杰金淋巴瘤活检标本,结果示9例T系淋巴瘤,8例B系淋巴廇,非T非B及未定型淋巴瘤各3例。病理组织学表现与免疫表型符合率B系达80%,T系达60%。故根据形态学表现估测免疫表型是可行的。经HTLV抗体血清检测,仅1例多形细胞性T淋巴瘤患者阳性。  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