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   99399篇
  免费   6792篇
  国内免费   2332篇
耳鼻咽喉   3229篇
儿科学   2286篇
妇产科学   1805篇
基础医学   3835篇
口腔科学   3180篇
临床医学   9974篇
内科学   10343篇
皮肤病学   801篇
神经病学   3805篇
特种医学   2236篇
外国民族医学   22篇
外科学   30829篇
综合类   13463篇
现状与发展   8篇
一般理论   2篇
预防医学   4687篇
眼科学   4601篇
药学   5380篇
  176篇
中国医学   1435篇
肿瘤学   6426篇
  2024年   206篇
  2023年   2316篇
  2022年   2977篇
  2021年   5030篇
  2020年   4905篇
  2019年   4274篇
  2018年   4167篇
  2017年   3637篇
  2016年   3715篇
  2015年   3780篇
  2014年   7401篇
  2013年   7055篇
  2012年   5780篇
  2011年   6071篇
  2010年   4859篇
  2009年   4647篇
  2008年   4526篇
  2007年   4510篇
  2006年   3986篇
  2005年   3456篇
  2004年   2977篇
  2003年   2406篇
  2002年   1951篇
  2001年   1829篇
  2000年   1542篇
  1999年   1424篇
  1998年   1194篇
  1997年   1101篇
  1996年   852篇
  1995年   703篇
  1994年   623篇
  1993年   519篇
  1992年   476篇
  1991年   427篇
  1990年   353篇
  1989年   308篇
  1988年   313篇
  1987年   291篇
  1986年   266篇
  1985年   304篇
  1984年   265篇
  1983年   180篇
  1982年   213篇
  1981年   174篇
  1980年   132篇
  1979年   91篇
  1978年   79篇
  1977年   63篇
  1976年   54篇
  1975年   36篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
目的:探讨消化道肿瘤中同源重组修复相关基因(homologous recombination repair related gene,HRR)突变的发生情况及临床意义。方法:共92例消化道肿瘤患者,79例患者进行了血液标本HRR检测,53例患者进行了组织标本HRR检测,40例患者同时行血液和组织的HRR基因检测,收集患者基因检测结果及临床相关资料。结果:在79例患者血液标本检测中发现10例(12.6%)有临床意义HRR突变,在53例患者组织标本检测中发现9例(17.0%)有临床意义HRR突变。40例同时行血液和组织的HRR基因检测患者中常见的有临床意义HRR突变为CDK12突变4例(10.0%)、ATM突变3例(7.5%)、BRCA1突变2例(5.0%)。13例有临床意义HRR突变患者中常见共存突变为TP53突变10例(76.9%)、APC突变5例(38.5%)、PIK3CA突变4例(30.8%)。40例患者中13例患者血液和/或组织中有临床意义HRR突变,27例患者血液和组织中均无任何临床意义HRR突变且两组相比,有临床意义HRR突变组肿瘤突变负荷(tumor mutational burden,TMB)为6.17(2.24~11.52),而未携带HRR突变组TMB为0.4(0~3.75),差异有统计学意义(P<0.05)。40例患者组织检测中7例HRR有临床意义的突变,33例无HRR突变,血液检测中10例HRR有临床意义的突变,30例无HRR突变,一致性检验的Kappa值为0.333(P=0.031)。结论:携带有临床意义HRR突变的消化道肿瘤患者TMB更高,血液和组织检测HRR突变有较好的一致性。  相似文献   
2.
3.
4.
《Cirugía espa?ola》2022,100(3):149-153
IntroductionThe Law for the Regulation of Health Professions (LOPS) indicates that health professionals will carry out continuous training throughout their professional life, and will regularly prove their professional competence. The objective of the study was to carry out a national survey to find out the opinion of Spanish surgeons and thus be able to prepare a recertification project by the Spanish Association of Surgeons (AEC).MethodsCross-sectional observational study carried out in June-July 2020, through a survey sent to the members of the AEC.ResultsThe survey had a total of 1230 visits and an overall completion rate of 784 responses (67.3%). 69.6% were unaware of the LOPS forecasts and 83.4% were unaware of similar initiatives in other specialties and 95.5% agreed to demand adequate information. 71.4% believed it necessary but only 57% believed that it should be mandatory. 82.9% would agree that it should be regulated through an objective and predictable official procedure.ConclusionsThe concept of re-accreditation is not well known in our specialty and in view of the results obtained, adequate and reliable information seems necessary. Therefore, it would be pertinent to propose by the AEC a specific project to assess activities and skills.  相似文献   
5.
6.
ObjectiveSpinal cord stimulation (SCS) is an effective treatment in failed back surgery syndrome (FBSS). We studied the effect of preimplantation opioid use on SCS outcome and the effect of SCS on opioid use during a two-year follow-up period.Materials and methodsThe study cohort included 211 consecutive FBSS patients who underwent an SCS trial from January 1997 to March 2014. Participants were divided into groups, which were as follows: 1) SCS trial only (n = 47), 2) successful SCS (implanted and in use throughout the two-year follow-up period, n = 131), and 3) unsuccessful SCS (implanted but later explanted or revised due to inadequate pain relief, n = 29). Patients who underwent explantation for other reasons (n = 4) were excluded. Opioid purchase data from January 1995 to March 2016 were retrieved from national registries.ResultsHigher preimplantation opioid doses associated with unsuccessful SCS (ROC: AUC = 0.66, p = 0.009), with 35 morphine milligram equivalents (MME)/day as the optimal cutoff value. All opioids were discontinued in 23% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.004). Strong opioids were discontinued in 39% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.04). Mean opioid dose escalated from 18 ± 4 MME/day to 36 ± 6 MME/day with successful SCS and from 22 ± 8 MME/day to 82 ± 21 MME/day with unsuccessful SCS (p < 0.001).ConclusionsHigher preimplantation opioid doses were associated with SCS failure, suggesting the need for opioid tapering before implantation. With continuous SCS therapy and no explantation or revision due to inadequate pain relief, 39% of FBSS patients discontinued strong opioids, and 23% discontinued all opioids. This indicates that SCS should be considered before detrimental dose escalation.  相似文献   
7.
8.
9.
ObjectiveNew-onset postoperative atrial fibrillation (POAF) after cardiac surgery is common, with rates up to 60%. POAF has been associated with early and late stroke, but its association with other cardiovascular outcomes is less known. The objective was to perform a meta-analysis of the studies reporting the association of POAF with perioperative and long-term outcomes in patients with cardiac surgery.MethodsWe performed a systematic review and a meta-analysis of studies that presented outcomes for cardiac surgery on the basis of the presence or absence of POAF. MEDLINE, EMBASE, and the Cochrane Library were assessed; 57 studies (246,340 patients) were selected. Perioperative mortality was the primary outcome. Inverse variance method and random model were performed. Leave-one-out analysis, subgroup analyses, and metaregression were conducted.ResultsPOAF was associated with perioperative mortality (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.58-2.33), perioperative stroke (OR, 2.17; 95% CI, 1.90-2.49), perioperative myocardial infarction (OR, 1.28; 95% CI, 1.06-1.54), perioperative acute renal failure (OR, 2.74; 95% CI, 2.42-3.11), hospital (standardized mean difference, 0.80; 95% CI, 0.53-1.07) and intensive care unit stay (standardized mean difference, 0.55; 95% CI, 0.24-0.86), long-term mortality (incidence rate ratio [IRR], 1.54; 95% CI, 1.40-1.69), long-term stroke (IRR, 1.33; 95% CI, 1.21-1.46), and longstanding persistent atrial fibrillation (IRR, 4.73; 95% CI, 3.36-6.66).ConclusionsThe results suggest that POAF after cardiac surgery is associated with an increased occurrence of most short- and long-term cardiovascular adverse events. However, the causality of this association remains to be established.  相似文献   
10.
Recent epidemiological studies suggested that proton pump inhibitor (PPI) use was associated with an increased risk of biliary tract cancer (BTC), however, confounders were not adequately controlled. Our study aimed to evaluate PPI use and subsequent risk of BTC and its subtypes in three well-established cohorts. We conducted a pooled analysis of the subjects free of cancers in UK Biobank (n = 463 643), Nurses' Health Study (NHS, n = 80 235) and NHS II (n = 95 869). Propensity score weighted Cox models were used to estimate marginal HRs of PPIs use on BTC risk, accounting for potential confounders. We documented 284 BTC cases in UK Biobank (median follow-up: 7.6 years), and 91 cases in NHS and NHS II cohorts (median follow-up: 15.8 years). In UK biobank, PPI users had a 96% higher risk of BTC compared to nonusers in crude model (HR 1.96, 95% CI 1.44-2.66), but the effect was attenuated to null after adjusting for potential confounders (HR 0.95, 95% CI 0.60-1.49). PPI use was not associated with risk of BTC in the pooled analysis of three cohorts (HR 0.93, 95% CI 0.60-1.43). We also observed no associations between PPI use with risk of intrahepatic (HR 1.00, 95% CI 0.49-2.04), extrahepatic bile duct (HR 1.09, 95% CI 0.52-2.27) and gallbladder cancers (HR 0.66, 95% CI 0.26-1.66) in UK Biobank. In summary, regular use of PPIs was not associated with the risk of BTC and its subtypes.  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