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   34644篇
  免费   3201篇
  国内免费   2551篇
耳鼻咽喉   393篇
儿科学   398篇
妇产科学   369篇
基础医学   4059篇
口腔科学   583篇
临床医学   4794篇
内科学   5016篇
皮肤病学   371篇
神经病学   1993篇
特种医学   1275篇
外国民族医学   25篇
外科学   3214篇
综合类   6528篇
现状与发展   11篇
预防医学   2132篇
眼科学   1112篇
药学   3498篇
  27篇
中国医学   1909篇
肿瘤学   2689篇
  2024年   127篇
  2023年   686篇
  2022年   1616篇
  2021年   1847篇
  2020年   1437篇
  2019年   1219篇
  2018年   1262篇
  2017年   1207篇
  2016年   1033篇
  2015年   1590篇
  2014年   1957篇
  2013年   1698篇
  2012年   2645篇
  2011年   2752篇
  2010年   1637篇
  2009年   1313篇
  2008年   1576篇
  2007年   1671篇
  2006年   1679篇
  2005年   1703篇
  2004年   1063篇
  2003年   1013篇
  2002年   890篇
  2001年   788篇
  2000年   811篇
  1999年   937篇
  1998年   605篇
  1997年   665篇
  1996年   496篇
  1995年   415篇
  1994年   354篇
  1993年   206篇
  1992年   272篇
  1991年   240篇
  1990年   202篇
  1989年   179篇
  1988年   168篇
  1987年   133篇
  1986年   101篇
  1985年   77篇
  1984年   34篇
  1983年   20篇
  1982年   27篇
  1981年   15篇
  1980年   8篇
  1979年   9篇
  1965年   2篇
  1940年   3篇
  1935年   2篇
  1934年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
The effect of adjuvant chemotherapy on survival of patients with thoracic esophageal squamous cell carcinomas is still controversial, and the subgroup of patients who will most likely benefit from the adjuvant chemotherapy on long‐term survival has not yet been identified clearly. Studies published from 1995 to May 2012 were searched in Medline, Embase, PubMed, Cancerlit, the Cochrane Library, CNKI and major scientific meetings. Randomized controlled trials and nonrandomized studies comparing surgery plus adjuvant chemotherapy with surgery alone in patients with resectable thoracic esophageal squamous cell carcinomas were included. Eleven studies with a total of 2047 patients were identified, consisting of the adjuvant chemotherapy arm (n = 887) and surgery‐alone arm (n = 1160). There was not statistically significant benefit on 3‐year overall survival for adjuvant chemotherapy (risk ratio [RR] = 0.89, 95% confidence interval [CI], 0.72 to 1.09; P = 0.25). Adjuvant chemotherapy could significantly prolong the 1‐year disease‐free survival (DFS) (RR = 0.68, 95%CI, 0.51 to 0.89; P = 0.006), but not 3‐year DFS (RR = 0.97, 95%CI, 0.73 to 1.29; P = 0.84). Further analysis showed that patients with stage III‐IV diseases could benefit from adjuvant chemotherapy on 3‐year overall survival (RR = 0.43, 95%CI, 0.31 to 0.61; P = 0.00001), but not in the case of patients with stageI‐IIdiseases (RR = 1.12, 95%CI, 0.65 to 1.93; P = 0.68). Additionally, patients with positive lymph node could benefit on 5‐year DFS from adjuvant chemotherapy (RR = 0.79, 95%CI, 0.64 to 0.99; P = 0.04). The modality treatment with adjuvant chemotherapy for patients with squamous cell carcinoma of thoracic esophagus might be determined according to pathological stage or the status of lymph node metastasis.  相似文献   
993.
994.
目的探讨布地奈德对脂多糖(LPS)诱导大鼠急性肺损伤的影响。方法将30只雄性Sprague Dawley大鼠随机分为3组:对照组、LPS组和布地奈德组,每组10只。采用经气管插管给予LPS(5 mg/kg)制备大鼠急性肺损伤模型;布地奈德组给予LPS 24 h后经气道给予布地奈德(500μg/kg)。3组均于48 h后测定肺水清除率,称量肺湿干重比,采用酶联免疫吸附试验测定支气管肺泡灌洗液中白细胞介素1β的水平,HE染色观察肺组织病理学改变,免疫组织化学法观察细胞间黏附分子1的表达。结果与LPS组相比,布地奈德干预后,肺组织结构破坏明显减轻,炎症细胞浸润减少,肺水清除率提高(P值均<0.01),肺湿干重比降低(P<0.05),支气管肺泡灌洗液中蛋白含量及中性粒细胞、巨噬细胞等的渗出减少(P<0.05或P<0.01),细胞间黏附分子1表达减少。结论布地奈德对LPS诱导的急性肺损伤大鼠具有肺保护作用,其机制考虑与减少细胞炎症反应、减少炎症因子对内皮细胞的活化、加强肺水清除作用有关。  相似文献   
995.
目的探讨表皮细胞生长因子受体酪氨酸激酶抑制剂(EGFR-TKIs)使用后耐药进展的肺腺癌患者给予局部治疗(冷冻消融、支气管动脉栓塞)联合EGFR-TKIs的临床疗效。方法回顾性分析2012年3月至2018年10月应急总医院经病理证实并完成随访的原发性EGFR敏感突变型晚期肺腺癌患者,进展后再行EGFR基因检测为T790M阴性,继续应用EGFR-TKIs的同时联合局部治疗,分别统计PFS1(从使用EGFR-TKIs到疾病进展时间)、PFS2(从冷冻消融到疾病进展时间)、OS(总生存期)、OS1(冷冻消融后的生存期),及冷冻消融后的并发症情况。分析OS及PFS的统计学相关影响因素。结果32例符合入组标准的晚期肺腺癌患者,PFS1平均时间为(12.4±8.6)个月。其中14例患者冷冻消融前行支气管动脉栓塞治疗,共消融病灶38个。PFS2为(6.7±2.9)个月。OS为(31.5±13.5)个月,其中OS1为(15.5±7.6)个月。统计分析显示PFS1与PFS2与OS存在显著相关性(P<0.05),靶向治疗进展后至氩氦冷冻消融的时间与患者的OS及OS1存在相关性,支气管动脉栓塞联合氩氦消融治疗后并发症主要为气胸及肺内出血,对症处理后均可缓解。结论EGFR-TKIs耐药进展后晚期肺腺癌中,EGFR-TKIs继续使用并联合冷冻消融等局部治疗可延长患者生存,并发症少,取得临床获益。  相似文献   
996.
Hemodialysis (HD) is the most important treatment for patients with end‐stage renal disease (ESRD). Thrombocytopenia is a potential treatment complication related to dialysis. Under normal circumstances, the platelet count would slightly decrease within the first hour of HD, but get restored towards the end of procedure. In most patients, the platelet count can be maintained within the normal range, and the occurrence of thrombocytopenia is relatively rare in clinical practice. Therefore, the possibility of thrombocytopenia in HD patients is often ignored. Moreover, thrombocytopenia might be misdiagnosed and mistreated. At present, almost all articles on the subject, apart from some case reports, focus on pseudothrombocytopenia and heparin‐induced thrombocytopenia. In this review, we summarized various underlying causes, mechanisms, and diagnostic approaches to thrombocytopenia in HD patients. The review aims to provide a guide for clinicians interested in the causes and adequate treatment of thrombocytopenia.  相似文献   
997.
Background: This retrospective cohort study aimed to explore the causes of death in children with congenital heart disease (CHD) after cardiac surgery in one of the biggest cardiac centers for children with CHD in China. Methods: A total of 26,856 children undergoing cardiac surgery from January 1, 2012 to December 31, 2019 were included. Based on the clinical data, the causes of death were divided into ten categories and further compared among different periods, types of CHD and surgical procedures. Results: Of all patients, 513 (1.9%) died (median age 162 d, median weight 5.6 kg). The mortality in 2016–2019 was lower than that in 2012–2015 (1.4 ± 0.3% vs. 2.5 ± 0.3%, p = 0.005). A total of 42.5% of children died of heart failure, and 32.9% died of residual anatomic defects. Patients with transposition of the great arteries tended to die from residual anatomic defects (21.9%), while those with double-outlet right ventricle (20%) and single ventricle (20%) tended to die from pulmonary hypertension (PH) (p = 0.006). After biventricular repair, children tended to die from heart failure (90.4%), while after single-ventricle repair, children tended to die from PH (50%) (p < 0.0001). There is a negative correlation between mortality and the ECMO implantation rate (r = −0.898, p = 0.002). Conclusions: Heart failure and residual anatomic defects were the main causes of death after cardiac surgery. The cause of death patterns differed among CHD types and surgical strategies. ECMO may be a life-saving tool when other conventional therapies do not work.  相似文献   
998.
999.
1000.
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