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   1410160篇
  免费   103695篇
  国内免费   2773篇
耳鼻咽喉   18430篇
儿科学   43715篇
妇产科学   38381篇
基础医学   211236篇
口腔科学   37795篇
临床医学   131604篇
内科学   275398篇
皮肤病学   31284篇
神经病学   112660篇
特种医学   54140篇
外国民族医学   265篇
外科学   198235篇
综合类   27652篇
现状与发展   8篇
一般理论   639篇
预防医学   113395篇
眼科学   31930篇
药学   105175篇
  7篇
中国医学   3587篇
肿瘤学   81092篇
  2021年   13917篇
  2019年   13296篇
  2018年   17542篇
  2017年   13325篇
  2016年   15230篇
  2015年   18389篇
  2014年   24468篇
  2013年   35291篇
  2012年   49273篇
  2011年   51330篇
  2010年   29793篇
  2009年   27880篇
  2008年   46262篇
  2007年   48792篇
  2006年   47698篇
  2005年   46471篇
  2004年   44081篇
  2003年   41599篇
  2002年   39831篇
  2001年   59551篇
  2000年   60308篇
  1999年   50747篇
  1998年   14535篇
  1997年   13110篇
  1996年   13484篇
  1995年   12675篇
  1994年   11729篇
  1992年   39496篇
  1991年   38972篇
  1990年   37534篇
  1989年   36270篇
  1988年   33631篇
  1987年   32844篇
  1986年   31312篇
  1985年   29478篇
  1984年   22451篇
  1983年   19625篇
  1982年   11688篇
  1979年   21348篇
  1978年   15724篇
  1977年   13112篇
  1976年   12121篇
  1975年   13057篇
  1974年   15879篇
  1973年   15625篇
  1972年   14751篇
  1971年   13728篇
  1970年   12970篇
  1969年   12229篇
  1968年   11364篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
SETTING: Tuberculosis (TB) cases reported from nine districts of Madrid, where the percentage of immigrant population varied from 1.9% in 1996 to 12.2% in 2003. OBJECTIVE: To describe the trends in TB incidence from 1994 to 2003. DESIGN: Observational study. RESULTS: Between 1994-1995 and 2002-2003, the TB rate decreased from 48.5 (95% CI 45.8-51.1) to 23.3 per 100000 population (95% CI 21.5-25.1) (P < 0.001). The percentage of TB cases co-infected with HIV decreased from 55.9% in 1994 to 14.3% in 2003 (P < 0.001), whereas TB cases in foreigners increased from 2.6% in 1994 to 33.7% in 2003 (P < 0.001). CONCLUSION: Although the TB rates showed a marked decrease in the study period, the increasing impact of immigration contributed to slowing down the trend.  相似文献   
93.
94.
95.
BACKGROUND: An augmented reality tool for computer assisted surgery named X-Scope allows visual tracking of real anatomical structures in superposition with volume rendered CT or MRI scans and thus can be used for navigated translocation of bony segments. METHODS: In a feasibility study X-Scope was used in orthognathic surgery to control the translocation of the maxilla after Le Fort I osteotomy within a bimaxillary procedure. The situation achieved was compared with the pre-operative situation by means of cephalometric analysis on lateral and frontal cephalograms. RESULTS: The technique was successfully utilized in 5 patients. Maxillary positioning using X-Scope was accomplished accurately within a range of 1mm. The tool was used in all cases in addition to the usual intra-operative splints. A stand-alone application without conventional control does not yet seem reasonable. CONCLUSION: Augmented reality tools like X-Scope may be helpful for controlling maxillary translocation in orthognathic surgery. The application to other interventions in cranio-maxillofacial surgery such as Le Fort III osteotomy, fronto-orbital advancement, and cranial vault reshaping or repair may also be considered.  相似文献   
96.
A series of 1-alkyl-3,4-dihydroisoquinolines and the related 4-alkyl-1,2-dihydro-benzo[f]isoquinolines was synthesized using reactions of dialkylbenzylcarbinols and their naphthyl analogs with alkylcyanides. Experiments showed that 1-alkyl-6,7-dimethoxy-3,4-dihydroisoquinolines typically produce a hypotensive action, while the benzo-annelated structures usually exhibit a hypertensive effects. The most active compound decreases the arterial pressure in cats by 52 Torr and the effect lasts for about 4 hours. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 3, pp. 15–17, March, 2006.  相似文献   
97.
French asthma patients may be supervised by general practitioners (GPs) and/or specialists. Therefore, this study examined asthma management in patients exclusively supervised by specialists (SPE), GPs, (GP) and both (GP+SPE group), and compared the findings. Asthma patients were consecutively recruited in 348 pharmacies. Each patient completed a questionnaire providing data on personal characteristics, asthma management, perception of disease and asthma supervision. Asthma control was measured using the Asthma Control Test. Questionnaires were linked to computerised records of medications which had been dispensed before inclusion in the study. From the 1,256 patients (mean age = 36.1 yrs, 54.3% females), 11.4, 36.6, and 52.0% were placed in the SPE, GP, and GP+SPE groups, respectively. During the previous 4 weeks, most patients in the SPE group were properly controlled (52.2 versus 26.4 and 21.5% in GP and GP+SPE groups, respectively). The SPE group made more use of fixed combinations of long-acting beta agonist and inhaled corticosteroid, while receiving less short-acting beta agonists, antitussives and antibiotics. Striking differences in symptoms and asthma management were observed according to the type of asthma supervision. The current results strongly support the need to improve the management of asthma in primary care, and the coordination of care between general practitioners and specialists.  相似文献   
98.
Coccidioidomycosis is an endemic fungal infection of the desert southwestern United States of particular concern for immunosuppressed renal transplant recipients. The clinical course of coccidioidomycosis can be severe in immunosuppressed patients, with high rates of dissemination and mortality, and antifungal prophylaxis is routinely administered to high-risk patients. We sought to determine the impact of coccidioidomycosis on patients who received their renal transplant at our hospital in Phoenix, Arizona. A retrospective records review of the first 205 patients who received a renal transplant between June 1999 and December 2003 identified 6 patients (3%) who had contracted coccidioidomycosis after transplantation. All six cases occurred more than 6 months after transplantation. Two of these six patients had disseminated coccidioidomycosis. Two patients, one with pulmonary infection and one with disseminated infection, died. None of the six patients with coccidioidomycosis after transplantation had identified risk factors before transplantation. No high-risk patient who received targeted antifungal prophylaxis had a reactivation of coccidioidomycosis after transplantation. Treatment for acute rejection and induction with antithymocyte globulin did not appear to increase the risk of subsequent coccidioidomycosis.  相似文献   
99.
Spinocerebellar ataxia (SCA) types 2 and 3 are autosomal-dominant neurodegenerative disorders caused by mutations in two different genes. We identified mutations for SCA2 and SCA3 segregating simultaneously in a single Brazilian family. The index patient had SCA2, whereas her two second-degree cousins had SCA3. Disease was more rapidly progressive in the SCA2 patient, who presented severe brainstem and pancerebellar atrophy, as opposed to the two SCA3 patients, who had only mild cerebellar vermian atrophy. In such situations, molecular confirmation of all patients may avoid misdiagnosis of SCA subtypes and eventual errors in predictive testing of unaffected family members.  相似文献   
100.
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