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   18170篇
  免费   1072篇
  国内免费   106篇
耳鼻咽喉   224篇
儿科学   442篇
妇产科学   497篇
基础医学   2787篇
口腔科学   428篇
临床医学   1681篇
内科学   3436篇
皮肤病学   615篇
神经病学   1317篇
特种医学   793篇
外科学   2735篇
综合类   171篇
现状与发展   1篇
一般理论   2篇
预防医学   995篇
眼科学   368篇
药学   1611篇
中国医学   175篇
肿瘤学   1070篇
  2023年   125篇
  2022年   103篇
  2021年   449篇
  2020年   264篇
  2019年   402篇
  2018年   657篇
  2017年   503篇
  2016年   581篇
  2015年   630篇
  2014年   893篇
  2013年   1096篇
  2012年   1590篇
  2011年   1595篇
  2010年   939篇
  2009年   631篇
  2008年   910篇
  2007年   894篇
  2006年   832篇
  2005年   806篇
  2004年   693篇
  2003年   560篇
  2002年   519篇
  2001年   465篇
  2000年   442篇
  1999年   345篇
  1998年   144篇
  1997年   113篇
  1996年   111篇
  1995年   103篇
  1994年   89篇
  1993年   53篇
  1992年   148篇
  1991年   129篇
  1990年   124篇
  1989年   85篇
  1988年   88篇
  1987年   84篇
  1986年   68篇
  1985年   72篇
  1984年   65篇
  1983年   49篇
  1982年   46篇
  1981年   45篇
  1980年   46篇
  1979年   55篇
  1977年   48篇
  1976年   47篇
  1975年   46篇
  1973年   42篇
  1972年   43篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Pharmaceutical Research - Fluid-bed coating processes make it possible to manufacture pharmaceutical products with tuneable properties. The choice of polymer type and coating thickness provides...  相似文献   
2.
Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml-1 or < 300 ng.ml-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l-1, 143 (133–150 [120–179]) g.l-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion.  相似文献   
3.
Rationale:The prone position is commonly used in spinal surgery. There have been many studies on hemodynamic changes in the prone position during general anesthesia. We report a rare case of transient left bundle branch block (LBBB) in a prone position.Patient concern:Electrocardiogram (ECG) of a 64-year-old man scheduled for spinal surgery showed normal sinus rhythm change to LBBB after posture change to the prone position.Diagnosis:Twelve lead ECG revealed LBBB. His coronary angio-computed tomography results showed right coronary artery with 30% to 40% stenosis and left circumflex artery with 40% to 50% stenosis. The patient was diagnosed with stable angina and second-degree atrioventricular block of Mobitz type II.Intervention:Nitroglycerin was administered intravenously during surgery. Adequate oxygen was supplied to the patient. After surgery, the patient was prescribed clopidogrel, statins, angiotensin II receptor blocker, and a permanent pacemaker was inserted.Outcome:Surgery was completed without complications. After surgery, the transient LBBB changed to a normal sinus rhythm. The patient did not complain of chest pain or dyspnea.Lesson:The prone position causes significant hemodynamic changes. A high risk of cardiovascular disease may cause ischemic heart disease and ECG changes. Therefore, careful management is necessary.  相似文献   
4.
PurposeTo evaluate the feasibility, safety, and effectiveness of N-butyl cyanoacrylate (NBCA) embolization for the treatment of aortic dissection.Materials and MethodsIn this single-center retrospective study conducted from February 2003 to June 2019, NBCA embolization of an aortic false lumen was attempted in 12 patients (median age, 59 y; range, 41–68 y) and thoracic endovascular aortic repair (TEVAR) was performed in 53 patients (median age, 59 y; range, 37–70 y) for aortic dissection with one or more indications of persisting pain, malperfusion, rupture or impending rupture, maximal aortic diameter ≥ 55 mm, and/or rapid aortic enlargement. The main exclusion criterion for embolization was the presence of fast blood flow in the aortic false lumen on aortography. The efficacy of NBCA embolization and TEVAR was compared by evaluating technical and clinical outcomes, repeat intervention–free survival (RFS), and overall survival (OS).ResultsTechnical success was achieved in 11 of the 12 patients treated with NBCA embolization (91.7%), and clinical success was achieved in 9 of these 11 (81.8%). No significant difference was found between embolization and TEVAR in clinical success rates (embolization, 81.8%; TEVAR, 84.9%; P = .409) or procedure-related complications (embolization, 1 patient [8.3%]; TEVAR, 4 patients [7.5%]; P = .701). In addition, embolization showed comparable 5-y RFS (embolization, 82.5% ± 9.3; TEVAR, 85.5% ± 4.8; P = .641) and 5-y OS (embolization, 100%; TEVAR, 95.4% ± 3.2; P = .744) rates to TEVAR.ConclusionsNBCA embolization of the false lumen in aortic dissection seems to be a safe and effective treatment modality for the closure of false lumen in selected patients.  相似文献   
5.
European Journal of Clinical Microbiology & Infectious Diseases - The multilocus variable-number tandem-repeat analysis (MLVA) typing method is commonly used in Mycoplasma pneumoniae (M....  相似文献   
6.
Clinical Oral Investigations - The aim of this study was the analysis of WNT10A variants in seven families of probands with various forms of tooth agenesis and self-reported family history of...  相似文献   
7.
Die Anaesthesiologie - Die COVID-19-Pandemie hat das deutsche Gesundheitssystem vor enorme Herausforderungen gestellt und den Bedarf an Strategien zu Rekrutierung, Schulung und Einsatzplanung von...  相似文献   
8.

Background

Although it is known that women do not participate in trials as frequently as men, there are limited recent data examining how women recruitment has changed over time.

Methods

We conducted MEDLINE search using a validated strategy for randomized trials published in New England Journal of Medicine, Lancet, and Journal of the American Medical Association between 1986 and 2015, and included trials evaluating pharmacologic or nonpharmacologic therapies. We abstracted data on demographics, intervention type, clinical indication, and trial design characteristics, and examined their relationships with women enrollment.

Results

In total, 598 trials met inclusion criteria. Women enrollment increased significantly over time (21% between 1986 and 1990 to 33% between 2011 and 2015; Pfor trend < 0.001) and did not differ by journal or funding source. Women enrollment varied with clinical indication, comprising 37% for non–coronary artery disease vascular trials, 30% for coronary artery disease trials, 28% for heart failure trials, and 28% for arrhythmia trials (P < 0.001), which were all significantly lower than the expected proportion in disease populations (P < 0.001). Women enrollment varied with trial type (31%, 29%, and 26% for pharmacologic, device, and procedural trials, respectively; P = 0.001). These findings were corroborated using multivariable analysis. We found significant positive correlations between women enrolled, and mean age and total number of participants. Fewer women were enrolled in trials reporting statistically significant results than those who did not (P = 0.001).

Conclusions

Although enrollment of women has increased over time, it remains lower than the relative proportion in the disease population. Future studies should elucidate the reasons for persistent under-representation of women in clinical trials.  相似文献   
9.
10.
肖瑾  李小军  黄建军  高圣权  陆昌洙  刘向前 《中草药》2020,51(22):5781-5787
目的 研究细柱五加Acanthopanax gracilistylus W.W.Smith中impressic acid(IA)对脂多糖(LPS)诱导的小鼠单核巨噬细胞RAW264.7的抗炎作用。方法 以LPS诱导RAW264.7细胞建立炎症模型;使用EZ4U细胞增殖与细胞毒性分析试剂盒检测IA对RAW264.7细胞的毒性作用;Griess法测定一氧化氮(NO)水平;ELISA法测肿瘤坏死因子-α(TNF-α)、白介素-1β(IL-1β)水平;RT-PCR法检测TNF-α、IL-1β mRNA表达;Western blotting检测高迁移率族蛋白B1(HMGB1)蛋白表达;ELISA法细胞质和细胞核的核因子-κB(NF-κB)水平。结果 Impressic acid可以显著抑制LPS诱导的RAW264.7细胞中TNF-α、IL-1β水平和HMGB1蛋白表达,并抑制NF-κB从细胞质向细胞核的转移(P<0.05、0.01)。结论 细柱五加中IA对LPS诱导的RAW264.7细胞具有抗炎作用。  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