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   13901篇
  免费   921篇
  国内免费   563篇
耳鼻咽喉   178篇
儿科学   449篇
妇产科学   198篇
基础医学   1627篇
口腔科学   292篇
临床医学   1426篇
内科学   2994篇
皮肤病学   279篇
神经病学   903篇
特种医学   454篇
外国民族医学   2篇
外科学   1424篇
综合类   1134篇
一般理论   2篇
预防医学   1068篇
眼科学   486篇
药学   1132篇
  6篇
中国医学   354篇
肿瘤学   977篇
  2024年   24篇
  2023年   128篇
  2022年   252篇
  2021年   456篇
  2020年   306篇
  2019年   371篇
  2018年   544篇
  2017年   385篇
  2016年   374篇
  2015年   492篇
  2014年   576篇
  2013年   680篇
  2012年   995篇
  2011年   1069篇
  2010年   634篇
  2009年   443篇
  2008年   732篇
  2007年   834篇
  2006年   657篇
  2005年   721篇
  2004年   612篇
  2003年   593篇
  2002年   564篇
  2001年   470篇
  2000年   504篇
  1999年   396篇
  1998年   127篇
  1997年   109篇
  1996年   113篇
  1995年   93篇
  1994年   56篇
  1993年   60篇
  1992年   154篇
  1991年   119篇
  1990年   106篇
  1989年   110篇
  1988年   93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   10篇
  1980年   11篇
  1979年   14篇
  1977年   12篇
  1976年   9篇
  1973年   9篇
  1970年   9篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
赛赓啶对 KBV200细胞多药抗性的逆转作用   总被引:3,自引:0,他引:3  
研究赛赓啶对KBV200细胞多药抗性的逆转作用及逆转机制。在KBV200细胞,采用MTT法,测出赛赓啶对长春新碱、阿霉素和鬼臼乙叉甙耐药的逆转系数分别为5.5,2.0和1.9,而对5-氟尿嘧啶、美法仑的细胞毒性作用无明显影响,表明赛赓啶为多药抗性逆转剂。荧光分光光度法测定表明,赛赓啶可使KBV200细胞内阿霉素蓄积量增加。流式细胞荧光测定显示赛赓啶可增加罗丹明123的蓄积并减慢其外排。免疫细胞化学及狭缝杂交表明赛赓啶不影响KBV200细胞的P-糖蛋白染色深度和 mdr1 RNA 表达水平。以上结果提示赛赓啶的多药抗性逆转机制是抑制P-糖蛋白泵的功能。  相似文献   
13.
成人高原心脏病临床分型的探讨   总被引:1,自引:1,他引:0  
本文总结了680例成人高原心脏病临床资料,依照其临床表现、X线、心电图等项检查,提出了临床上较为实用的诊断和分型意见。  相似文献   
14.
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   
15.
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   
16.
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   
17.
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   
18.
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   
19.
Summary A rapid and quantitative method for the determination of benzodiazepines using high-performance liquid chromatography (HPLC) with diode-array detection (DAD) is reported. The drugs were extracted from serum, blood or post-mortem blood using C18 extraction columns. Brotizolam was used as internal standard. Experiments with spiked serum/blood samples resulted in recoveries between 75% and 94% for all investigated benzodiazepines. Excellent linearity was obtained over the concentration range 5–1500 ng benzodiazepine/ml. The limit of detection was approximately 2 ng/ml. The detection of low therapeutic serum levels of highly potent benzodiazepines is also possible.   相似文献   
20.
The possible immunoregulatory role of the tonsils was studied by determining immunoglobulins IgG, A, M, E and factors C'3, C'4 and PFB of the complement system before and after tonsillectomy. The synthesis in vitro of IgG and IgM by lymphocytes stimulated with pokeweed mitogen was also measured. There were statistically significant differences between pre and post-operative levels of serum IgG, IgA and IgM, which decreased after surgery. Practically no change in the mean values of IgE and no significant differences in the levels of serum C'3, C'4, and PFB, were found. The in-vitro synthesis of both immunoglobulins (IgG, IgM) by lymphocytes increased significantly after tonsillectomy. Our results suggest that not only does tonsillectomy have no counterproductive effect on the immune system, but that, on the contrary, it seems to improve the immune response, since it appears to unblock the suppression to which the immune system was subject.  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