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   134336篇
  免费   13518篇
  国内免费   9201篇
耳鼻咽喉   1055篇
儿科学   1854篇
妇产科学   1419篇
基础医学   12490篇
口腔科学   2578篇
临床医学   18861篇
内科学   16124篇
皮肤病学   1635篇
神经病学   4781篇
特种医学   4634篇
外国民族医学   45篇
外科学   10388篇
综合类   29386篇
现状与发展   41篇
一般理论   8篇
预防医学   12785篇
眼科学   3658篇
药学   15517篇
  239篇
中国医学   10820篇
肿瘤学   8737篇
  2024年   552篇
  2023年   2070篇
  2022年   5252篇
  2021年   6600篇
  2020年   5415篇
  2019年   4041篇
  2018年   4077篇
  2017年   4539篇
  2016年   3810篇
  2015年   6351篇
  2014年   7794篇
  2013年   7998篇
  2012年   11956篇
  2011年   12622篇
  2010年   9716篇
  2009年   8078篇
  2008年   8875篇
  2007年   8548篇
  2006年   7541篇
  2005年   6688篇
  2004年   4452篇
  2003年   4108篇
  2002年   3350篇
  2001年   2610篇
  2000年   2192篇
  1999年   1684篇
  1998年   975篇
  1997年   999篇
  1996年   752篇
  1995年   638篇
  1994年   590篇
  1993年   342篇
  1992年   322篇
  1991年   304篇
  1990年   267篇
  1989年   209篇
  1988年   202篇
  1987年   179篇
  1986年   115篇
  1985年   90篇
  1984年   45篇
  1983年   41篇
  1982年   15篇
  1981年   11篇
  1980年   7篇
  1979年   14篇
  1978年   2篇
  1975年   4篇
  1974年   3篇
  1973年   5篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
11.
OBJECTIVE: To evaluate the short-term therapeutic effect of percutaneous transluminal coronary angioplasty (PTCA) with stent implantation in the treatment of myocardial infarction with severe pump failure. METHODS: The clinical data of 73 patients receiving PTCA and stent implantation for myocardial infarction with severity pump failure were analyzed and grouped according the occurrence of complications, degree of the vascular lesions and the complexity of the surgical procedures. Preoperative and postoperative ventricular ejection fractions (LVEF) were compared in each case. RESULTS: The degree of vascular lesions and surgical complexity were not shown to relate to the occurrence of the complications. Except in cases complicated by chronic renal dysfunction, significant improvement was achieved in the patients 7 d after the operation (P<0.05), regardless of different degrees of vascular lesions and surgical complexity. CONCLUSION: PTCA with stent implantation is effective to improve the short-term cardiac function of patients with myocardial infarction and severe pump failure.  相似文献   
12.
医院档案综合管理的意义及对策   总被引:4,自引:0,他引:4  
刘晓卿  肖燕 《现代医院》2005,5(12):147-148
对我国医院目前档案管理的现状,档案信息资源在医院现代化建设中的作用以及实行医院档案综合管理的重要意义及对策进行了全面系统地分析,强调了实现医院档案规范化、科学化和现代化管理的重要性和紧迫性。  相似文献   
13.
林岑  胡雁 《中国肿瘤》2007,16(8):606-609
全文以Walker和Avant概念分析格式介绍坚强(hardiness)的定义和特征,说明案例,分析前置因子和后果,列举坚强的评估方法和在不同人群中的运用.希望通过对坚强的全面分析加深医务人员对此概念的理解,从而有助于激发患者的坚强特质.  相似文献   
14.
Epidural hematoma following use of a three-point skull clamp.   总被引:1,自引:0,他引:1  
We report an unusual case of epidural hematoma secondary to the use of a three-point skull-fixation device. Initially, a posterior-fossa brain tumor with hydrocephalus was diagnosed in a 15-year-old boy. Midline suboccipital craniectomy was performed with the patient placed in the prone position. A Mayfield (Ohio Medical Instrument Co., Cincinnati, OH, USA) skull clamp was used for fixation of the head during the surgical procedure, following which, a huge epidural hematoma developed within 6 hours of surgery, due to skull penetration and fracture at one of the clamp's pin sites located proximate to the coronal suture.  相似文献   
15.
Neurons in the monkey cerebral cortex containing nicotinamideadenine dinucleotide phosphate-diaphorase (NADPH-d) can he dividedinto two distinct types, both nonpyramidal. Type I neurons havea large soma (diameter 20–50 µm), a dense NADPH-dhistochemical reaction. and are distributed throughout the cortex,but mainly in the subcortical white matter, and are mostly aspiny.Type II cells have a small soma (< 20 µm) with lightNADPH-d reactivity and are distributed primarily in the supragranularlayers, particularly layers II and upper III. The numericaldensity of type II cells is much greater than that of type I.Type I neurons also stain for GABA and a few intracortical typeI cells contain calbindin. All type II cells found here arecolocalized with both GABA and calbindin. Neither type I nortype II cells are stained for parvalbumin. Together with previous observations that almost all corticalNADPH-d cells in various subprimates are like type I cells,we suggest that type II cells may form a group of NADPH-d-richneurons differentiated in higher mammalian cortex from a subpopulationof calbindin-containing GABAergic interneurons, and these nitricoxide-synthesizing cells may play a role in control of intracorticalneuronal activity characteristic of higher cerebral functionsin advanced mammals.  相似文献   
16.
目的 解决南方红豆杉细胞生长缓慢及代谢水平低下的问题。方法 对对数期(20d)和静止期(30d)的红豆杉细胞分别进行继代,在整个生长周期中测定了培养基中的碳源、氮源、磷酸盐的变化并分析了红豆杉细胞生长及紫杉醇的合成情况。结果 对数期继代细胞吸收碳源和硝态氮早于静止期继代的细胞,且前者的比生长速度是后者的1.5倍,紫杉醇含量提高了近4倍。结论 对数期继代有利于生物量的积累及紫杉醇的合成。  相似文献   
17.
本文对103名高龄老人进行营养情况调查、心理状况调查和体测量,结果表明:高龄老人体质指数大于26者很少,只要老龄人的各种营养素达到供给量标准,心理状态乐观满意,且不吸烟不酗酒者,则可长命百岁。  相似文献   
18.
We have adapted the simple and sensitive McAb-antigen spot test (AST) for evaluating the efficacy of anti-Leishmania chemotherapy. Serum samples from 37 kala-azar patients were tested by McAb-AST, and all showed definite positive reactions before treatment. After a course of antimony treatment, 20 turned negative, coupled with the disappearance of clinical symptoms; another 12 cases responded with weak positivity accompanied by an improvement of clinical manifestations; and the remaining 5 antimony-resistant patients showed strong positive reactions, with their conditions gradually worsening. Furthermore, all 6 cases in which the diagnosis was missed by the bone marrow smear method turned McAb-AST negative after chemotherapy. These results suggest that McAb-AST can be used to evaluate the efficacy of chemotherapy as well as to avoid missed diagnosis by the bone marrow smear method.  相似文献   
19.
Senile macular degeneration   总被引:1,自引:0,他引:1  
M Yan 《中华眼科杂志》1987,23(6):313-6, 21
  相似文献   
20.
PURPOSE: Type I IFNs (IFN-alpha/beta) have shown significant antitumor activity in preclinical models but limited efficacy and significant toxicity in clinical trials. We hypothesized that the antitumor activity of type I IFNs could be enhanced by chronic, low-dose systemic delivery and sought to test this in murine neuroblastoma models. EXPERIMENTAL DESIGN: Continuous liver-generated expression of human IFN-beta (hINF-beta) was achieved through a gene therapy-mediated approach using adeno-associated virus vectors encoding hIFN-beta (AAV hINF-beta). Orthotopic localized retroperitoneal and disseminated models of neuroblastoma were established using three different xenografts. Immunohistochemical analysis and ELISA were used to evaluate the antiangiogenic effect of therapy. RESULTS: The development of both localized orthotopic (retroperitoneal) and disseminated neuroblastoma was prevented in all mice expressing hINF-beta. Continued growth of established retroperitoneal tumors, treated with AAV hINF-beta as monotherapy, was significantly restricted, and survival for mice with established, disseminated disease was significantly prolonged following administration of AAV hINF-beta. Analysis of treated tumors revealed a significant antiangiogenic effect. Mean intratumoral vessel density was diminished and expression of the angiogenic factors vascular endothelial growth factor and basic fibroblast growth factor were both decreased. Finally, combination therapy in which AAV hIFN-beta was used together with low-dose cyclophosphamide resulted in regression of both established retroperitoneal and disseminated disease. CONCLUSIONS: AAV-mediated delivery of hIFN-beta when used as monotherapy was able to restrict neuroblastoma growth due in part to inhibition of angiogenesis. When used in combination with conventional chemotherapy, AAV hIFN-beta was able to effect complete tumor regression.  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