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   67013篇
  免费   4054篇
  国内免费   1685篇
耳鼻咽喉   128篇
儿科学   1960篇
妇产科学   935篇
基础医学   4053篇
口腔科学   102篇
临床医学   8431篇
内科学   17873篇
皮肤病学   105篇
神经病学   1543篇
特种医学   4019篇
外国民族医学   3篇
外科学   5861篇
综合类   12352篇
现状与发展   5篇
预防医学   3716篇
眼科学   776篇
药学   7263篇
  57篇
中国医学   2285篇
肿瘤学   1285篇
  2024年   83篇
  2023年   810篇
  2022年   1673篇
  2021年   2371篇
  2020年   2267篇
  2019年   1946篇
  2018年   2027篇
  2017年   1958篇
  2016年   2118篇
  2015年   2154篇
  2014年   4420篇
  2013年   5329篇
  2012年   3870篇
  2011年   4013篇
  2010年   3379篇
  2009年   3248篇
  2008年   3164篇
  2007年   3435篇
  2006年   3046篇
  2005年   2600篇
  2004年   2192篇
  2003年   1941篇
  2002年   1564篇
  2001年   1553篇
  2000年   1284篇
  1999年   1109篇
  1998年   948篇
  1997年   944篇
  1996年   775篇
  1995年   847篇
  1994年   740篇
  1993年   525篇
  1992年   517篇
  1991年   433篇
  1990年   386篇
  1989年   338篇
  1988年   335篇
  1987年   294篇
  1986年   256篇
  1985年   337篇
  1984年   299篇
  1983年   123篇
  1982年   223篇
  1981年   191篇
  1980年   190篇
  1979年   122篇
  1978年   92篇
  1977年   90篇
  1976年   71篇
  1974年   32篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
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   
24.
25.
PurposeTo evaluate the potential differences in non-target embolization and vessel microsphere filling of a reflux-control microcatheter (RCM) compared to a standard end-hole microcatheter (SEHM) in a swine model.Materials and methodsRadiopaque microspheres were injected with both RCM and SEHM (2.4-Fr and 2.7-Fr) in the kidneys of a preclinical swine model. Transarterial renal embolization procedures with RCM or SEHM were performed in both kidneys of 14 pigs. Renal arteries were selectively embolized with an automated injection protocol of radio-opaque microspheres. Ex-vivo X-ray microtomography images of the kidneys were utilized to evaluate the embolization by quantification of the deposition of injected microspheres in the target vs. the non-target area of injection. X-ray microtomography images were blindly analyzed by five interventional radiologists. The degree of vessel filling and the non-target embolization were quantified using a scale from 1 to 5 for each parameter. An analysis of variance was used to compare the paired scores.ResultsTotal volumes of radio-opaque microspheres injected were similar for RCM (11.5 ± 3.6 [SD] mL; range: 6–17 mL) and SEHM (10.6 ± 5.2 [SD] mL; range: 4–19 mL) (P = 0.38). The voxels enhanced ratio in the target (T) vs. non-target (NT) areas was greater with RCM (T = 98.3% vs. NT = 1.7%) than with SEHM (T = 89% vs. NT = 11%) but the difference was not significant (P = 0.30). The total score blindly given by the five interventional radiologists was significantly different between RCM (12.3 ± 2.1 [SD]; range: 6–15) and the standard catheter (11.3 ± 2.5 [SD]; range: 4–15) (P = 0.0073), with a significant decrease of non-target embolization for RCM (3.8 ± 1.3 [SD]; range: 3.5–4.2) compared to SEHM (3.2 ± 1.5 [SD]; range: 2.9–3.5) (P = 0.014).ConclusionIn an animal model, RCM microcatheters reduce the risk of non-target embolization from 11% to 1.7%, increasing the delivery of microspheres of 98% to the target vessels, compared to SEHM microcatheters.  相似文献   
26.
27.
28.
29.
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   
30.
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