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   83425篇
  免费   5311篇
  国内免费   846篇
耳鼻咽喉   1572篇
儿科学   1008篇
妇产科学   1254篇
基础医学   14100篇
口腔科学   2195篇
临床医学   7456篇
内科学   15337篇
皮肤病学   2924篇
神经病学   6207篇
特种医学   4837篇
外科学   11018篇
综合类   358篇
现状与发展   3篇
一般理论   30篇
预防医学   3806篇
眼科学   1829篇
药学   7767篇
中国医学   1046篇
肿瘤学   6835篇
  2023年   627篇
  2022年   2014篇
  2021年   3125篇
  2020年   1553篇
  2019年   2039篇
  2018年   2560篇
  2017年   2004篇
  2016年   2887篇
  2015年   3978篇
  2014年   4562篇
  2013年   5288篇
  2012年   7872篇
  2011年   7274篇
  2010年   4239篇
  2009年   3508篇
  2008年   5032篇
  2007年   4530篇
  2006年   3899篇
  2005年   3557篇
  2004年   2944篇
  2003年   2532篇
  2002年   2167篇
  2001年   1754篇
  2000年   1610篇
  1999年   1204篇
  1998年   513篇
  1997年   379篇
  1996年   299篇
  1995年   250篇
  1994年   234篇
  1993年   206篇
  1992年   441篇
  1991年   456篇
  1990年   395篇
  1989年   363篇
  1988年   345篇
  1987年   327篇
  1986年   260篇
  1985年   227篇
  1984年   172篇
  1983年   149篇
  1982年   85篇
  1981年   88篇
  1979年   136篇
  1978年   107篇
  1975年   102篇
  1974年   92篇
  1972年   92篇
  1971年   87篇
  1970年   83篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
Sometimes the clinical differentiation between verruca plana (VP) and VP‐like seborrheic keratosis (SK) could be challenged. However, there have been no studies on this issue to date. The aim of this study was to elucidate clinical and dermoscopic differences between these two diseases, and also to suggest a diagnostic algorithm of VP and VP‐like SK without skin biopsy. The patients who had lesions clinically considered as VP or VP‐like SK were the target of our study. We took clinical and dermoscopic photos with informed consent and conducted a questionnaire. All patients had their diagnoses confirmed by biopsy. Thirty‐three patients were enrolled in our study. Seventeen patients were finally diagnosed with VP (51.5%) and 16 patients with VP‐like SK (48.5%). In clinical findings, VP‐like SK showed significantly more scattered distribution than VP (P = 0.039), which exhibited more clustered or grouped distribution (P = 0.039). In dermoscopic findings, brain‐like appearance was more commonly observed in VP‐like SK (P = 0.003) whereas VP showed more red dots or globular vessels (P = 0.017) and even‐colored light brown to yellow patch (P < 0.001). Sex, onset age, the size of each lesion, location, color and shape showed no significant differences between them (P > 0.05). Based on our results, we suggest a diagnostic algorithm using Koebner's phenomenon, dermoscopic findings, distribution of each lesion and biopsy for multiple VP‐like lesions in adults, and we think it will be a very useful diagnostic tool in daily clinical dermatological practice.  相似文献   
33.
34.
Fluid is usually restricted during thoracic surgery, and vasoactive agents are often administered to maintain blood pressure. One-lung ventilation (OLV) decreases arterial oxygenation; thus oxygen delivery to the brain can be decreased. In this study, we compared phenylephrine and dopamine with respect to maintaining cerebral oxygenation during OLV in major thoracic surgery.Sixty-three patients undergoing lobectomies were randomly assigned to the dopamine (D) or phenylephrine (P) group. The patients’ mean arterial pressure was maintained within 20% of baseline by a continuous infusion of dopamine or phenylephrine. Maintenance fluid was kept at 5 mL/kg/h. The depth of anesthesia was maintained with desflurane 1MAC and remifentanil infusion under bispectral index guidance. Regional cerebral oxygen saturation (rScO2) and hemodynamic variables were recorded using near-infrared spectroscopy and esophageal cardiac Doppler.The rScO2 was higher in the D group than the P group during OLV (OLV 60 min: 71 ± 6% vs 63 ± 12%; P = 0.03). The number of patients whose rScO2 dropped more than 20% from baseline was 0 and 6 in the D and P groups, respectively (P = 0.02). The D group showed higher cardiac output, but lower mean arterial pressure than the P group (4.7 ± 1.0 vs 3.9 ± 1.2 L/min; 76.7 ± 8.1 vs 84.5 ± 7.5 mm Hg; P = 0.02, P = 0.02). Among the variables, age, hemoglobin concentration, and cardiac output were associated with rScO2 by correlation analysis.Dopamine was superior to phenylephrine in maintaining cerebral oxygenation during OLV in thoracic surgery.  相似文献   
35.
36.
37.
Recent studies have reported an association between gastroesophageal reflux disease (GERD) and atrial fibrillation (AF). The objective of the present study was to evaluate whether AF is one of the risk factors for GERD occurrence.In this hospital-based, retrospective, case–control study, the patients were classified into 2 groups. The patients diagnosed with new AF were assigned to the AF group (n = 1612); those diagnosed without AF and GERD were assigned to the control group (n = 1612). The subjects in the control group were selected from outpatients of total healthcare center without a history of AF or GERD, and matched for age and gender. We evaluated the incidence of GERD and risk factors for GERD occurrence between the 2 groups.The number of patients experiencing occurrence of GERD during the follow-up period was significantly higher in the AF group than those in the control group, respectively (129 patients vs 98 subjects, P = 0.037). The incidence of GERD was significantly higher in the AF group than in the control group by Kaplan–Meier analysis with log-rank test (P = 0.008). The AF group''s adjusted hazard ratio of GERD occurrence against that of the control group was 1.37 (95% confidence interval [CI]: 1.16–1.57; P = 0.009) according to Cox''s proportional hazard model.The presence of AF appears to increase the incidence of GERD and may be considered a risk factor for the development of GERD. Further, large prospective and cohort studies will be required to better establish the correlation of GERD with AF.  相似文献   
38.
Quality of Life Research - This study investigated the PROMIS Self-Efficacy Measure for Managing Chronic Conditions (PROMIS-SE) domain distributions and examined the factor structure of the...  相似文献   
39.
40.
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