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   231901篇
  免费   20637篇
  国内免费   5171篇
耳鼻咽喉   3335篇
儿科学   4562篇
妇产科学   3851篇
基础医学   19995篇
口腔科学   7780篇
临床医学   20702篇
内科学   23655篇
皮肤病学   2559篇
神经病学   12473篇
特种医学   6468篇
外国民族医学   12篇
外科学   23138篇
综合类   36095篇
现状与发展   12篇
一般理论   24篇
预防医学   28759篇
眼科学   2129篇
药学   25095篇
  334篇
中国医学   26890篇
肿瘤学   9841篇
  2023年   4347篇
  2022年   6675篇
  2021年   10593篇
  2020年   10727篇
  2019年   11979篇
  2018年   10746篇
  2017年   9333篇
  2016年   8439篇
  2015年   8004篇
  2014年   15401篇
  2013年   16098篇
  2012年   13919篇
  2011年   14723篇
  2010年   11892篇
  2009年   10473篇
  2008年   9852篇
  2007年   9903篇
  2006年   8507篇
  2005年   7288篇
  2004年   5992篇
  2003年   5398篇
  2002年   4228篇
  2001年   3638篇
  2000年   3220篇
  1999年   2678篇
  1998年   2066篇
  1997年   1947篇
  1996年   1589篇
  1995年   1664篇
  1994年   1579篇
  1993年   1388篇
  1992年   1302篇
  1991年   1173篇
  1990年   1054篇
  1989年   991篇
  1988年   927篇
  1987年   896篇
  1986年   785篇
  1985年   2094篇
  1984年   2371篇
  1983年   1464篇
  1982年   1934篇
  1981年   1376篇
  1980年   1192篇
  1979年   1068篇
  1978年   891篇
  1977年   700篇
  1976年   824篇
  1975年   575篇
  1974年   473篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
BackgroundPretest probability (PTP) calculators utilize epidemiological-level findings to provide patient-level risk assessment of obstructive coronary artery disease (CAD). However, their limited accuracies question whether dissimilarities in risk factors necessarily result in differences in CAD. Using patient similarity network (PSN) analyses, we wished to assess the accuracy of risk factors and imaging markers to identify ≥50% luminal narrowing on coronary CT angiography (CCTA) in stable chest-pain patients.MethodsWe created four PSNs representing: patient characteristics, risk factors, non-coronary imaging markers and calcium score. We used spectral clustering to group individuals with similar risk profiles. We compared PSNs to a contemporary PTP score incorporating calcium score and risk factors to identify ≥50% luminal narrowing on CCTA in the CT-arm of the PROMISE trial. We also conducted subanalyses in different age and sex groups.ResultsIn 3556 individuals, the calcium score PSN significantly outperformed patient characteristic, risk factor, and non-coronary imaging marker PSNs (AUC: 0.81 vs. 0.57, 0.55, 0.54; respectively, p ?< ?0.001 for all). The calcium score PSN significantly outperformed the contemporary PTP score (AUC: 0.81 vs. 0.78, p ?< ?0.001), and using 0, 1–100 and ?> ?100 cut-offs provided comparable results (AUC: 0.81 vs. 0.81, p ?= ?0.06). Similar results were found in all subanalyses.ConclusionCalcium score on its own provides better individualized obstructive CAD prediction than contemporary PTP scores incorporating calcium score and risk factors. Risk factors may not be able to improve the diagnostic accuracy of calcium score to predict ≥50% luminal narrowing on CCTA.  相似文献   
82.
目的 系统评价益气活血法联合西药治疗特发性肺纤维化(idiopathic pulmonary fibrosis,IPF)的疗效及安全性。方法 系统检索中国知网、维普网、万方数据库、EMbase、PubMed、Cochrane Library图书馆等数据库,检索时限从数据库建库至2021年1月,纳入益气活血法联合西药治疗特发性肺纤维化的随机对照试验(randomized controlled trial,RCT),由2名研究人员独立筛选并交叉核对纳入结果,提取有效数据后,应用RevMan 5.3软件进行Meta分析。结果 纳入16项随机对照试验共计1160例IPF患者。分析结果显示益气活血法联合西药组可提高临床总有效率(OR= 3.71,95% CI [2.68,5.14],P<0.00001);改善患者肺功能:用力肺活量(MD=0.31,95% CI [0.23,0.38],P<0.00001)(MD=3.59,95% CI [1.51,5.66],P=0.0007),一氧化碳弥散量(MD=2.54,95% CI [1.83,3.25],P<0.00001);提高生活质量,降低圣乔治评分:呼吸困难(MD=-12.70,95% CI [-21.07,-4.32],P=0.003),活动能力(MD=-8.38,95% CI [-13.66,-3.10],P=0.002),疾病影响(MD=-13.87,95% CI [-22.53,-5.22],P=0.002);并可降低患者中医症状积分:喘息(MD=-0.66,95% CI [-0.84,-0.49],P<0.00001),咳嗽(MD=-0.71,95% CI [-1.04,-0.37],P<0.0001);有效提高动脉血氧分压(MD=5.92,95% CI [4.61,7.22],P<0.00001);且不增加不良事件发生率(OR=0.55,95% CI [0.27,1.14],P=0.11)。结论 益气活血法联合西药治疗IPF可提高临床治疗有效率,改善患者生活质量,且不增加临床不良事件(便秘、嗜睡、口干、恶心呕吐、皮肤瘙痒、腹泻等)发生率。但本研究纳入文献质量参差不齐,仍需更多大样本、高质量、多中心的RCT试验验证结论。  相似文献   
83.
ObjectivesTinnitus can induce disabling psychological suffering, requiring an integrative multimodal approach, combining neuromodulation and psychotherapeutic methods. We sought to evaluate the therapeutic efficacy and acceptability of Eye Movement Desensitization and Reprocessing (EMDR) in tinnitus.Materials and methodsThis was a single-center prospective non-comparative study. Inclusion criteria comprised: adult patient, with chronic tinnitus, Tinnitus Handicap Inventory (THI) score > 17, causing psychological distress motivating active treatment after ineffective “classic” treatment (combining advice, sound therapy and first-line drug treatment), and agreement to EMDR therapy. Therapeutic efficacy was defined by a decrease in THI or Visual Analog Scale (VAS) scores. Treatment acceptability was defined by the rate of included patients who completed therapy.ResultsThirty-eight patients were included. There was a significant reduction of 53.5% in THI score in 78.9% of patients (P < 0.0001; 64.8 ± 20.8 before versus 31.8 ± 24.7 after treatment), and of 51% in VAS score in 76.3% of patients (P < 0.0001; 7.24 ± 2.12 before versus 3.58 ± 2.03 after treatment). The treatment acceptability was 86.8%.ConclusionEMDR appeared to be an effective alternative that was acceptable to the majority of patients, after failure of “classic” first-line treatment, improving quality of life in tinnitus patients and thus relieving disability.  相似文献   
84.
85.
86.
87.
88.
BackgroundCoronary artery bypass grafting (CABG) improves survival in patients with heart failure and severely reduced left ventricular systolic function (LVEF). Limited data exist regarding adverse cardiovascular event rates after CABG in patients with heart failure with midrange ejection fraction (HFmrEF; LVEF > 40% and < 55%).MethodsWe analyzed data on isolated CABG patients from the Veterans Affairs national database (2010-2019). We stratified patients into control (normal LVEF and no heart failure), HFmrEF, and heart failure with reduced LVEF (HFrEF) groups. We compared all-cause mortality and heart failure hospitalization rates between groups with a Cox model and recurrent events analysis, respectively.ResultsIn 6533 veterans, HFmrEF and HFrEF was present in 1715 (26.3%) and 566 (8.6%) respectively; the control group had 4252 (65.1%) patients. HFrEF patients were more likely to have diabetes mellitus (59%), insulin therapy (36%), and previous myocardial infarction (31%). Anemia was more prevalent in patients with HFrEF (49%) as was a lower serum albumin (mean, 3.6 mg/dL). Compared with the control group, a higher risk of death was observed in the HFmrEF (hazard ratio [HR], 1.3 [1.2-1.5)] and HFrEF (HR, 1.5 [1.2-1.7]) groups. HFmrEF patients had the higher risk of myocardial infarction (subdistribution HR, 1.2 [1-1.6]; P = .04). Risk of heart failure hospitalization was higher in patients with HFmrEF (HR, 4.1 [3.5-4.7]) and patients with HFrEF (HR, 7.2 [6.2-8.5]).ConclusionsHeart failure with midrange ejection fraction negatively affects survival after CABG. These patients also experience higher rates myocardial infarction and heart failure hospitalization.  相似文献   
89.
90.
BackgroundThere is increasing research interest regarding physical activity behavior among persons with multiple sclerosis (MS), yet there is little known about physical activity and its correlates in Black persons with MS.ObjectiveThis cross-sectional study assessed associations among social cognitive theory (SCT) variables and device-measured and self-reported physical activity in samples of Black and White persons with MS.MethodsParticipants included 67 Black and 141 White persons with MS who wore an ActiGraph accelerometer on a belt around the waist measuring moderate-to-vigorous physical activity (MVPA) for seven days and completed a battery of questionnaires. Questionnaires included demographic and clinical characteristics, leisure-time exercise, exercise self-efficacy, overcoming barriers self-efficacy, function, social support, exercise outcome expectations, and goal setting and planning.ResultsBlack participants with MS engaged in significantly less MVPA, but not sedentary behavior or light physical activity, than the White participants with MS. Black participants further had significantly lower levels of exercise self-efficacy and outcome expectations than the White sample. All SCT correlates were significantly correlated with self-reported physical activity, but only exercise and barriers self-efficacy, perceived function, and exercise goal setting were associated with device-measured MVPA. The difference in physical activity between Black and White participants with MS was accounted for by differences in exercise self-efficacy and outcome expectations.ConclusionsResearchers should consider developing behavioral interventions that target exercise self-efficacy and outcome expectations as SCT variables for increasing physical activity in Black persons with MS.  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