首页 | 官方网站   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   34608篇
  免费   2026篇
  国内免费   322篇
医药卫生   36956篇
  2023年   207篇
  2022年   296篇
  2021年   983篇
  2020年   617篇
  2019年   732篇
  2018年   982篇
  2017年   757篇
  2016年   850篇
  2015年   1003篇
  2014年   1277篇
  2013年   1624篇
  2012年   2382篇
  2011年   2430篇
  2010年   1457篇
  2009年   1367篇
  2008年   2198篇
  2007年   2188篇
  2006年   2017篇
  2005年   1886篇
  2004年   1888篇
  2003年   1724篇
  2002年   1627篇
  2001年   642篇
  2000年   560篇
  1999年   563篇
  1998年   347篇
  1997年   294篇
  1996年   291篇
  1995年   250篇
  1994年   178篇
  1993年   185篇
  1992年   326篇
  1991年   281篇
  1990年   269篇
  1989年   285篇
  1988年   211篇
  1987年   189篇
  1986年   193篇
  1985年   158篇
  1984年   148篇
  1983年   123篇
  1982年   82篇
  1981年   84篇
  1980年   64篇
  1979年   71篇
  1977年   48篇
  1976年   45篇
  1974年   51篇
  1969年   45篇
  1968年   42篇
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
101.
102.
103.
OBJECTIVE: To investigate the association between the use of fluoroquinolone agents and the risk of tendinitis in a large population-based case-control study. METHODS: The study was performed by linking automated health databases from the Region of Lombardia, Italy. Cases were patients aged > or =18 years who had a hospital discharge diagnosis of non-traumatic tendinitis in 2002-3. For each case, up to five controls were randomly selected among those eligible for inclusion in the study. A conditional logistic regression model was used to estimate the odds ratio of tendinitis associated with the current, recent and past use of fluoroquinolones. Odds ratios were adjusted for exposure to other antibacterials and other drugs. RESULTS: 22,194 cases and 104,906 controls met the inclusion criteria. Current use of fluoroquinolones significantly increased the risk of tendon disorders as a whole (odds ratio [OR] = 1.7; 95% CI 1.4, 2.0), tendon rupture (OR = 1.3; 95% CI 1.0, 1.8) and rupture of the Achilles' tendon (OR = 4.1; 95% CI 1.8, 9.6). Concomitant use of corticosteroids and fluoroquinolones increased the risk of both tendon rupture (OR = 3.1; 95% CI 1.5, 6.3) and rupture of the Achilles' tendon (OR = 43.2; 95% CI 5.5, 341.1). DISCUSSION: Evidence that exposure to fluoroquinolones is associated with the sudden occurrence of tendinitis is supported by this large population-based study. We can estimate that a single case of rupture of the Achilles' tendon would occur for every 5958 persons treated with fluoroquinolones (95% CI 2148, 23,085). The corresponding number needed to harm is 979 (95% CI 122, 9172) for patients who concomitantly use corticosteroids and 1638 (95% CI 351, 8843) for those aged >60 years. CONCLUSION: Clinicians should be aware of this adverse effect, and the increased risk for fluoroquinolone-associated tendinitis in elderly patients with corticosteroid use must be considered when these agents are prescribed.  相似文献   
104.
From January 1970 through December 1987, 135 patients with cervical cancer in stage IIB (FIGO criteria) were treated by means of exclusive radiotherapy in the Istituto del Radio of the Brescia University. Thirty cases were treated by exclusive external-beam radiotherapy (RTT), 39 by brachytherapy (CU) plus external-beam radiotherapy, 24 by combined RTT and CU, 41 by RTT + CU + RTT, and 1 case by CU alone. Crude survival at 5 years is 52.4%, and NED survival is 50%. The differences between the values of crude and NED survival by radiotherapy technique were statistically significant (p 0.05), ranging from 69.8% in the RTT + CU group to 35.5% in the RTT alone group. Twenty-four cases (18%) failed to obtain complete remission, and 24 more cases recurred in the pelvis. Sequelae were evaluated by the French-Italian glossary; they were present in 62 cases (46%), but in 12 cases only (9%) they were severe. The incidence of sequelae was highest in the groups of patients treated with the combined techniques (RTT and CU) which allowed best disease control.  相似文献   
105.
The most common cause of bilateral internuclear ophthalmoplegia is multiple sclerosis. Wernicke's encephalopathy has been reported as a cause of unilateral internuclear ophthalmoplegia but not of bilateral internuclear ophthalmoplegia. In this report, we present the case of a patient with a history of alcohol abuse and acute onset of bilateral internuclear ophthalmoplegia whose clinical course and diagnostic studies are most consistent with a diagnosis of Wernicke's encephalopathy.  相似文献   
106.
107.
OBJECTIVE: A relationship between brain atrophy and delta rhythmicity (1.5-4 Hz) has been previously explored in Alzheimer's disease (AD) subjects [Fernandez A, Arrazola J, Maestu F, Amo C, Gil-Gregorio P, Wienbruch C, Ortiz T. Correlations of hippocampal atrophy and focal low-frequency magnetic activity in Alzheimer disease: volumetric MR imaging-magnetoencephalographic study. Am J Neuroradiol. 2003 24(3):481-487]. In this study, we tested the hypothesis that such a relationship does exist not only in AD patients but also across the continuum of subjects with mild cognitive impairment (MCI) and AD. METHODS: Resting, eyes-closed EEG data were recorded in 34 MCI and 65 AD subjects. EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). EEG cortical sources were estimated by LORETA. Cortical EEG sources were correlated with MR-based measurements of lobar brain volume (white and gray matter). RESULTS: A negative correlation was observed between the frontal white matter and the amplitude of frontal delta sources (2-4 Hz) across MCI and AD subjects. CONCLUSIONS: These results confirmed for the first time the hypothesis that the sources of resting delta rhythms (2-4 Hz) are correlated with lobar brain volume across MCI and AD subjects. SIGNIFICANCE: The present findings support, at least at group level, the 'transition hypothesis' of brain structural and functional continuity between MCI and AD.  相似文献   
108.
In his 2005 dissertation,Les Malvacées en-Phytothérapie (The Malvaceae in Phytotherapy), the author reviews the traditional uses and the most recent studies about the Malvaceae family. In the extract below, the author summarizes the data concerning plants of the Hibiscus genus.  相似文献   
109.
110.
The role of spontaneous and voluntary abortions was assessed in a case-control study conducted in Milan, northern Italy on 953 cases of epithelial ovarian cancer (median age, 54) and 2500 control subjects (median age, 52) in hospital for acute diseases other than malignant, gynecological, or hormonal disorders. Overall the inverse relationship between total number of incomplete pregnancies and ovarian cancer risk was statistically significant, estimated relative risks (RRs) being, respectively, 0.9 (95% confidence interval (CI), 0.7-1.1) for one abortion and 0.8 (95% CI, 0.6-1.0) for two or more as compared to none. Furthermore, the protections afforded by spontaneous and voluntary abortions were well comparable (RRs 0.7 and 0.8 for > or = 2 spontaneous and voluntary abortions, respectively, versus none). While the protective effect of incomplete pregnancy was not explicable in terms of other characteristics of women nor significantly different across strata of reproductive factors or oral contraceptive use, it seemed more marked in women whose ovarian cancer occurred below age 50. Etiologically, these findings suggest that interrupted pregnancy per se and not predisposition to spontaneous abortion affects ovarian cancer risk.  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-23

京公网安备 11010802026262号