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   12475篇
  免费   1021篇
  国内免费   314篇
耳鼻咽喉   28篇
儿科学   273篇
妇产科学   146篇
基础医学   987篇
口腔科学   28篇
临床医学   1557篇
内科学   3298篇
皮肤病学   33篇
神经病学   614篇
特种医学   1407篇
外国民族医学   3篇
外科学   1566篇
综合类   1725篇
预防医学   284篇
眼科学   78篇
药学   1014篇
  7篇
中国医学   220篇
肿瘤学   542篇
  2024年   9篇
  2023年   198篇
  2022年   291篇
  2021年   502篇
  2020年   499篇
  2019年   524篇
  2018年   534篇
  2017年   492篇
  2016年   428篇
  2015年   486篇
  2014年   797篇
  2013年   1014篇
  2012年   665篇
  2011年   749篇
  2010年   577篇
  2009年   640篇
  2008年   571篇
  2007年   632篇
  2006年   515篇
  2005年   428篇
  2004年   351篇
  2003年   318篇
  2002年   287篇
  2001年   252篇
  2000年   198篇
  1999年   171篇
  1998年   160篇
  1997年   143篇
  1996年   134篇
  1995年   135篇
  1994年   150篇
  1993年   105篇
  1992年   97篇
  1991年   86篇
  1990年   68篇
  1989年   67篇
  1988年   51篇
  1987年   53篇
  1986年   57篇
  1985年   66篇
  1984年   59篇
  1983年   24篇
  1982年   46篇
  1981年   39篇
  1980年   36篇
  1979年   24篇
  1978年   22篇
  1977年   17篇
  1976年   13篇
  1974年   9篇
排序方式: 共有10000条查询结果,搜索用时 921 毫秒
1.
2.
3.
4.
5.
Although an inverse relationship between body mass index (BMI) and baroreflex sensitivity (BRS) was found, the effect of waist circumference (WC) on BRS is still inconclusive. The contradictory results of previous studies may be related to the heterogeneity and relatively small sample size of the subjects examined. The aim of this population-based study was to investigate whether the influence of increased WC is more detrimental to BRS than BMI. A total of 760 community dwellers were recruited and they were classified into Q1 (n = 189), Q2 (n = 183), Q3 (n = 192) and Q4 (n = 196) groups, based on WC quartiles. Spontaneous BRS was determined by spectral α coefficient method. Valsalva ratio was the longest RR interval after release of Valsalva maneuver divided by the shortest RR interval during maneuver. Cardiac autonomic function was calculated by power spectrum of heart rate in low and high frequency (LF, 0.04–0.15 Hz; HF, 0.15–0.40 Hz), and LF/HF ratio in supine position for five minutes. There were significant differences in spontaneous BRS and Valsalva ratio among different WC groups. In multivariate analysis, obesity was inversely associated with spontaneous BRS and Valsalva ratio. However, these inverse relationships became insignificant after further adjustment for WC quartiles. In contrast, Q4 vs. Q1, Q3 vs. Q1 and Q2 vs. Q1 of WC were inversely related to spontaneous BRS. Q4 vs. Q1 and Q3 vs. Q1 of WC were negatively associated with the Valsalva ratio. In conclusion, increased and even high-normal WC had a stronger adverse effect on BRS than BMI, independent of cardio-metabolic risk factors.  相似文献   
6.
7.
PurposeTo explore the safety and effectiveness of bronchial artery (BA) embolization (BAE) in children with pulmonary hemorrhage.Materials and MethodsBetween February 2016 and February 2019, 41 patients (median age, 4 y; interquartile range, 2.3-8 y; median weight, 17.6 kg; interquartile range, 12.3–23.6 kg) underwent BAE. The indication of BAE included massive hemoptysis in 10 patients (24.4%), recurrent hemoptysis in 18 patients (43.9%), and refractory anemia in 13 patients (31.7%). The main etiology of pulmonary hemorrhage included pulmonary hemosiderosis (58.5%), congenital heart disease (17.1%), and infection (14.6%). A retrospective review was conducted of clinical outcomes of BAE.ResultsThere were 44 embolization sessions, with a total of 137 embolized vessels. Pulmonary hemorrhage was caused by BAs in 30 cases, nonbronchial systemic arteries plus BAs in 10, and nonbronchial systemic arteries in 1. Embolic particles were used in 30 cases (24 polyvinyl alcohol [PVA] and 6 microsphere), coils in 9 cases, and particles plus coils in 5 cases (4 PVA and 1 microsphere). Technical success (ability to embolize abnormal vessel) was achieved in 97.6% of patients (40 of 41), and clinical success (complete or partial resolution of hemoptysis within 30 days of embolization) was achieved in 90.2% (37 of 41). There was 1 procedure-related complication (2.4%) of cerebral infarction and 1 death from multiple-organ dysfunction (2.4%). Bleeding-free survival rates at 6, 12, 24, and 36 months were 92.5%, 83.9%, 83.9%, and 70.8%, respectively.ConclusionsBAE is a safe and effective procedure in children with pulmonary hemorrhage.  相似文献   
8.
目的 探讨肝动脉化疗栓塞(transcatheter arterial chemoembolization,TACE)术前天冬氨酸氨基转移酶与淋巴细胞比值(aspartate aminotransferase to lymphocyte ratio index,ALRI)在原发性肝癌并门脉癌栓(primary liver cancer-portal vein tumor thrombosis,PLC-PVTT)患者预后预测中的价值。方法 选取2013年11月21日至2018年8月22日于广西医科大学附属肿瘤医院接受TACE治疗的175例PLC-PVTT患者为研究对象。采用时间依赖性ROC曲线确定ALRI的最佳临界值。采用Cox 回归模型分析总生存期(overall survival,OS)的独立预测因素,Kaplan-Meier法计算生存率。结果 ROC曲线显示,ALRI的最佳临界值为49.37,对应曲线下面积为0.71。Kaplan-Meier分析显示,ALRI>49.37的患者OS较ALRI≤49.37的患者短(P=0.003)。Cox 回归分析结果显示,ALRI>49.37、行1次以上TACE治疗、Child-Pugh分级B级、凝血酶原时间≥13 s是患者TACE术后OS的独立危险因素(均P<0.05)。结论 TACE术前ALRI>49.37是PLC-PVTT患者OS的独立危险因素。  相似文献   
9.
10.
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   
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