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   23591篇
  免费   1094篇
  国内免费   228篇
耳鼻咽喉   46篇
儿科学   1069篇
妇产科学   157篇
基础医学   1528篇
口腔科学   14篇
临床医学   3231篇
内科学   5701篇
皮肤病学   39篇
神经病学   221篇
特种医学   1847篇
外科学   2027篇
综合类   4217篇
预防医学   1603篇
眼科学   7篇
药学   2007篇
  23篇
中国医学   584篇
肿瘤学   592篇
  2024年   17篇
  2023年   270篇
  2022年   710篇
  2021年   846篇
  2020年   740篇
  2019年   575篇
  2018年   606篇
  2017年   604篇
  2016年   686篇
  2015年   726篇
  2014年   1690篇
  2013年   1524篇
  2012年   1557篇
  2011年   1589篇
  2010年   1296篇
  2009年   1259篇
  2008年   1272篇
  2007年   1343篇
  2006年   1173篇
  2005年   1000篇
  2004年   747篇
  2003年   595篇
  2002年   445篇
  2001年   478篇
  2000年   377篇
  1999年   351篇
  1998年   285篇
  1997年   259篇
  1996年   175篇
  1995年   232篇
  1994年   198篇
  1993年   144篇
  1992年   133篇
  1991年   109篇
  1990年   109篇
  1989年   95篇
  1988年   92篇
  1987年   83篇
  1986年   56篇
  1985年   75篇
  1984年   68篇
  1983年   20篇
  1982年   65篇
  1981年   42篇
  1980年   36篇
  1979年   41篇
  1978年   31篇
  1977年   31篇
  1976年   19篇
  1974年   11篇
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
11.
BackgroundSome chronic obstructive pulmonary disease (COPD) patients develop hypoxemia with disease progression, with some even requiring long-term oxygen therapy (LTOT). Lung function, especially diffusing capacity, and the annual decline in PaO2, are reported to be predictive factors of chronic respiratory failure. However, the association between lung morphometry evaluated using computed tomography (CT) images and LTOT initiation is unknown.MethodsWe retrospectively evaluated the relationship between clinical indices, including pulmonary function, body mass index (BMI), and CT parameters, at baseline and LTOT initiation in two prospective COPD cohorts. In the Nara Medical University cohort (n = 76), the low attenuation area (LAA) and its fractal dimension (fractal D) were adapted as the indices for parenchymal destruction in CT images. The association between these CT measurements and LTOT initiation was replicated in the Kyoto University cohort (n = 130).ResultsIn the Nara Medical University cohort, lower BMI (hazard ratio [HR]:0.70, p = 0.006), lower % diffusing capacity (%DLCO) (HR: 0.92, p = 0.006), lower %DLCO/VA (HR, 0.90, p = 0.008), higher RV/TLC (HR, 1.26, p = 0.012), higher LAA% (HR: 1.18, p = 0.001), and lower fractal D (HR: 3.27 × 10?8, p < 0.001) were associated with LTOT initiation. Multivariate analysis in the Kyoto University cohort confirmed that lower %DLCO and lower fractal D were independently associated with LTOT initiation, whereas LAA% was not.ConclusionFractal D, which is the index for morphometric complexity of LAA in CT analysis, is predictive of LTOT initiation in COPD patients.  相似文献   
12.
13.
Chronic obstructive pulmonary disease (COPD) is a significant health problem in developed countries. We aimed to estimate the prevalence of COPD in a single Spanish healthcare area. We also aimed to assess if there are any differences in prevalence and spirometry use among primary care services by utilizing already registered information. We designed a cross-sectional study to determine the prevalence of COPD and the performance of spirometries in each primary care service. A total of 8,444 patients were diagnosed with COPD, with a prevalence of 2.6% for individuals older than 39 years. The prevalence increased with age and was much higher in men. Significant heterogeneity was found in the prevalence of COPD and spirometry use among primary care services. COPD was underdiagnosed and there was wide variability in spirometry use in our area. Greater efforts are needed to diagnose COPD in order to improve its clinical outcomes and to refine registries so that they can be used as reliable sources of information  相似文献   
14.
15.
16.
BackgroundComplete surgical removal is currently considered to be the best treatment option for pulmonary sarcomatoid carcinoma (PSC) especially in early stage operable disease; however, the reported recurrence-free survival is low. Benefits of adjuvant chemotherapy in PSC patients are still controversial, and there is no obvious agreement on the optimal treatment modalities of this disease. Therefore, we aimed to investigate the prognosis in terms of overall survival (OS) in patients with PSC who received adjuvant chemotherapy.MethodsThe review protocol was registered in PROSPERO (CRD42022306084). Patients with PSC who underwent surgical therapy with or without adjuvant chemotherapy were included into the meta-analysis. Hazard ratios (HR) with 95% confidence intervals (CIs) for OS were pooled and ROBINS-I tool was used to assess risk of bias of the included studies.ResultsWe identified four retrospective cohort studies with 6768 records from MEDLINE, Embase, and CENTRAL databases up to 9th September 2021, and altogether 1835 patients were included to the analysis. The present meta-analysis shows that patients receiving adjuvant chemotherapy had a significantly longer OS than patients who underwent surgical treatment alone (HR = 0.5657, 95%CI: 0.4391–0.7290, p < 0.0001).ConclusionsDespite the limited information on the chemotherapy regimens in the included studies, patients with PSC may benefit from adjuvant chemotherapy. More publications are required to evaluate and compare efficient adjuvant chemotherapy protocols in PSC cases.  相似文献   
17.
18.
19.
20.
目的 了解2009-2019年西安市肺结核的流行特征及治疗转归情况,为完善西安市肺结核防治策略提供依据。方法 收集2009-2019年《传染病信息管理系统》中登记的肺结核患者病案信息数据,通过描述性研究方法对肺结核流行病学特征和治疗转归情况进行分析。结果 2009-2019年间西安市肺结核年平均发病率为49.06/10万。郊县、郊区、城区肺结核年平均发病率分别为54.13/10万、47.46/10万和46.19/10万;男性发病率是女性的1.85倍。职业分布排在前5位的为农民(47.48%),家政、家务及待业(14.65%),离退人员(9.55%),学生(8.63%)和工人(5.23%)。利福平敏感或耐药性未知患者的成功治疗率平均为98.03%,利福平耐药患者治疗成功率为51.47%。结论 西安市近年来肺结核发病率和治疗率呈增长趋势,利福平耐药患者治疗成功率较低,要加强对重点人群的健康促进工作,加大肺结核发现力度及患者治疗管理工作。  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