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   89395篇
  免费   3913篇
  国内免费   1158篇
耳鼻咽喉   518篇
儿科学   1429篇
妇产科学   980篇
基础医学   11080篇
口腔科学   3823篇
临床医学   7069篇
内科学   17663篇
皮肤病学   1842篇
神经病学   6208篇
特种医学   2450篇
外国民族医学   5篇
外科学   14206篇
综合类   6055篇
现状与发展   3篇
一般理论   5篇
预防医学   7048篇
眼科学   1658篇
药学   5969篇
  19篇
中国医学   2979篇
肿瘤学   3457篇
  2023年   1222篇
  2022年   1739篇
  2021年   3610篇
  2020年   2525篇
  2019年   6492篇
  2018年   6635篇
  2017年   4222篇
  2016年   1565篇
  2015年   1533篇
  2014年   3093篇
  2013年   3095篇
  2012年   2223篇
  2011年   2629篇
  2010年   2208篇
  2009年   1876篇
  2008年   2035篇
  2007年   1980篇
  2006年   1752篇
  2005年   1494篇
  2004年   1313篇
  2003年   1368篇
  2002年   987篇
  2001年   969篇
  2000年   843篇
  1999年   790篇
  1998年   618篇
  1997年   637篇
  1996年   524篇
  1995年   518篇
  1994年   471篇
  1993年   409篇
  1992年   377篇
  1991年   339篇
  1990年   281篇
  1989年   259篇
  1988年   246篇
  1987年   201篇
  1985年   3021篇
  1984年   3545篇
  1983年   2960篇
  1982年   3451篇
  1981年   3134篇
  1980年   2590篇
  1979年   2561篇
  1978年   2092篇
  1977年   1574篇
  1976年   2021篇
  1975年   1524篇
  1974年   1330篇
  1973年   1279篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
91.
92.
93.
ObjectiveProgrammed death ligand 1 (PD-L1) has been reported to be connected to prognosis in individuals with malignant pleural mesothelioma (MPM), although there is no consensus based on data from previous studies. Accordingly, this quantitative meta-analysis investigated prognostic and clinicopathological utility of PD-L1 in patients with MPM.MethodsA comprehensive search of the PubMed, Web of Science, Embase, and Cochrane Library databases for articles published up to October 4, 2019 was performed. Studies using immunohistochemical techniques to detect/quantify the expression of PD-L1 in MPM tissue were enrolled in the analysis. The combined hazard ratio (HR) and corresponding 95% confidence interval (CI) was applied to assess the association between PD-L1 expression and overall survival (OS).ResultsA total of 11 studies comprising 1606 patients was included in the present meta-analysis. For OS, pooled data revealed an HR of 1.50 (95% CI 1.32–1.70; p < 0.001), suggesting that patients with PD-L1 overexpression experience inferior OS. Subgroup analysis revealed that elevated PD-L1 remained a significant prognostic indicator for worse OS, irrespective of sample size, cut-off value, ethnicity, and Newcastle-Ottawa Scale score. Moreover, PD-L1 overexpression was associated with non-epithelioid histology (odds ratio 4.30 [95% CI 1.89–9.74]; p < 0.001).ConclusionsResults of this meta-analysis show that elevated expression of PD-L1 could be a factor predicting poorer survival in patients with MPM.  相似文献   
94.
95.
96.
97.
98.
99.
BackgroundThere is limited information about the long-term outcome of obstructive sleep apnea (OSA) diagnosed in children and adolescents for educational and social factors. Here, we estimate the long-term socioeconomic outcome and health care costs of OSA.MethodsThe historical case-control cohort study included Danish individuals with OSA diagnosed in childhood or adolescence between 1994 and 2015. Health care costs and socioeconomic data were obtained from nationwide administrative and health registers. A total of 5419 were diagnosed during this period; of these we traced 1004 patients who we compared with 4085 controls (mean index age, 10.2 years; Standard Deviation (SD), 5.6 years) until the age of 20 years. Controls were matched for age, gender, and residency.ResultsComparing the OSA patient and control groups at age 20 years we found: 1) lower parental educational level; 2) significantly lower educational level also after adjustment for parental educational level; 3) lower school grade-point averages; 4) lower employment rate and lower income, which was not fully compensated when transfer payments were considered; and 5) patients' initial health care costs were higher due to higher morbidity. Patients showed higher mortality rates than controls (Hazard Ratio (HR) = 7.63, 95% CI = 4.87–11.95, P < 0.001).ConclusionsOSA in children and adolescent is associated with a significant influence on morbidity, mortality, educational level, grading, social outcome, and welfare consequences.  相似文献   
100.
Objectives: The present study aims to evaluate the role of Positron emission tomography (PET) -computed tomography (CT) with 18F-fluorodeoxyglucose (18F-FDG) in the restaging of high-risk testicular cancer. Methods: Forty-five patients (mean age of 38.1±11.3 years and range 23-81 years) with testicular carcinoma, underwent 18F-FDG PET-CT during their clinical course were prospectively selected. PET positivity was defined as a site of abnormal 18F-FDG uptake in tissue histologically proven or clinically or radiographically suspected to represent tissue involvement. The sites of disease were characterized as either nodal or extranodal. All patients were followed-up for at least 12 months with a diagnostic and/or functional imaging modality. Results: Of the 45 patients 38 (84%) patient presented with seminoma and 7 (16%) were Non-seminomatous germ cell tumors. Analysis of secondary disease spectrum showed nodal involvement in 65%, osseous involvement in 23% and mixed visceral/soft tissue lesions in 12% of patients. Nineteen (42%) were negative for any metastatic disease. All negative patients remain disease free in the follow-up of one year. Out of the positive 26/45 patients, PET-CT showed progressive disease in 3/26, stable disease 1/26 and partial response in 2/26 and complete metabolic resolution in 20/26 patients. 18F-FDG PET-CT was able to characterize all patients leading to significant change of primary decision of wait and watch to go for treatment and vice versa. Conclusion: 18F-FDG PET-CT scan is potentially an excellent tool for characterization of equivocal lesions on CT scan in the restaging settings and follow up of high-risk testicular cancer patients.  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