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   115491篇
  免费   11839篇
  国内免费   9193篇
耳鼻咽喉   1080篇
儿科学   1126篇
妇产科学   1160篇
基础医学   12997篇
口腔科学   2023篇
临床医学   16329篇
内科学   16071篇
皮肤病学   1206篇
神经病学   6405篇
特种医学   4227篇
外国民族医学   62篇
外科学   10805篇
综合类   21333篇
现状与发展   33篇
一般理论   14篇
预防医学   8189篇
眼科学   3487篇
药学   12230篇
  143篇
中国医学   7896篇
肿瘤学   9707篇
  2024年   453篇
  2023年   1950篇
  2022年   5482篇
  2021年   6664篇
  2020年   5189篇
  2019年   4082篇
  2018年   4434篇
  2017年   3898篇
  2016年   3689篇
  2015年   5673篇
  2014年   7022篇
  2013年   6281篇
  2012年   8924篇
  2011年   10156篇
  2010年   6468篇
  2009年   5182篇
  2008年   6235篇
  2007年   5972篇
  2006年   5964篇
  2005年   5748篇
  2004年   3495篇
  2003年   3381篇
  2002年   2728篇
  2001年   2326篇
  2000年   2372篇
  1999年   2367篇
  1998年   1557篇
  1997年   1482篇
  1996年   1198篇
  1995年   1100篇
  1994年   904篇
  1993年   569篇
  1992年   647篇
  1991年   546篇
  1990年   491篇
  1989年   459篇
  1988年   374篇
  1987年   320篇
  1986年   251篇
  1985年   200篇
  1984年   103篇
  1983年   52篇
  1982年   42篇
  1981年   42篇
  1980年   25篇
  1979年   23篇
  1978年   1篇
  1975年   1篇
  1964年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Annals of Surgical Oncology - Black women with breast cancer have a worse overall survival compared with White women; however, no difference in Oncotype DX? (ODX) recurrence scores has been...  相似文献   
992.
Study Design: Systematic review and meta-analysis.Objective: To compare the effectiveness and safety between anterior and posterior approach, and determine the best surgical methods for the treatment of ossification of the posterior longitudinal ligament (OPLL) in the cervical spine.Methods: We searched the Cochrane Library, PubMed, CNKI and Wanfang Med Data databases from January 2007 to March 2018. Japanese Orthopaedic Association (JOA) scores, cervical lordosis, functional recovery rates, excellent and good outcomes of the surgical approaches, and complication and reoperation rates were analyzed. RevMan 5.3 was utilized for data analysis.Results: Eleven studies were included in the meta-analysis. By comparing the anterior and posterior approaches for the treatment of OPLL in the cervical spine, statistically significant differences were found in the preoperative initial JOA, the postoperative final JOA scores, functional recovery rates, complication rates, excellent and good outcomes of the surgical approaches and reoperation rates. However, no statistically significant difference in the occurrence of the preoperative and postoperative cervical lordosis was noted.Conclusion: The anterior approach is superior to the posterior approach in terms of the postoperative final JOA score, functional recovery rate, and clinical outcomes. Although the complication and reoperation rates of the anterior approach are higher than those of the posterior approach. We recommend the anterior approach for the treatment of OPLL when patients with occupying ratio ≥ 60%. In addition, high-quality studies with long-term follow-up and large sample size are also needed.  相似文献   
993.
994.
Objective: Our study aimed to evaluate short- and long-term outcomes of patients who required emergent conversion from transcatheter aortic valve implantation (TAVI) to open surgery. Besides, the reasons and procedural settings of emergent cardiac surgery (ECS) were also reported.Methods: We retrospectively reviewed the patients who underwent TAVI in our institution between 2012 and 2019 and collected the clinical data of cases who converted from TAVI to bail-out surgery. Telephone and outpatient follow-ups were performed.Results: Of 516 TAVI patients, 20 required ECS, and the bail-out surgery occurred less frequently with the increase in TAVI volume. The most common reason for conversion was left ventricular perforation (7/20, 35.0%). Thirty-day mortality was 35.0% in ECS patients. Kaplan–Meier survival curves showed that the cumulative survival rate was 65.0% at 1 year, 50.1% at 5 years in all ECS patients, and 77.1% at 5 years in patients who survived over 30 days after conversion.Conclusion: Although the bail-out operation was performed immediately after TAVI abortion, ECS still associated with high 30-day mortality. The long-term survival benefit was seen in patients surviving from bail-out surgery. An experienced TAVI team is of crucial importance in avoiding ECS-related life-threatening complications and providing effective salvage surgery.  相似文献   
995.
996.
997.
998.
BackgroundBariatric surgery is effective for polycystic ovary syndrome (PCOS), while the exact mechanism remains unclear.ObjectivesTo assess the impact of bariatric surgery on PCOS patients and further explore the possible mechanism.SettingA meta-analysis.MethodsWe searched PubMed, Web of Science, The Cochrane Library, and Embase to identify relevant studies published before November 2020.ResultsTwenty-one studies met our inclusion criteria, and we identified 552 patients with PCOS study. Results showed that the prevalence of preoperative PCOS, menstrual irregularity, hirsutism, type 2 diabetes (T2D), hypertension, infertility, and depression significantly decreased after bariatric surgery. Levels of total testosterone, fasting insulin, and luteinizing hormone (LH) decreased and estradiol increased, while levels of follicle-stimulating hormone (FSH) and LH/FSH did not show significant changes during the 3-month follow-up. There were decreases in testosterone and fasting insulin levels when the postoperative follow-up time was 6 months or ≥12 months. Levels of fasting blood glucose and triglycerides were significantly reduced after 6 months or ≥12 months of bariatric surgery. High-density lipoprotein (HDL) and sex hormone-binding globulin (SHBG) significantly improved ≥12 months after bariatric surgery.ConclusionSymptoms of PCOS and related complications are significantly alleviated after bariatric surgery. In addition, we found a significant improvement on anomalous secretion of gonadotropins, glucose metabolism, and lipid metabolism in patients with PCOS after bariatric surgery.  相似文献   
999.
目的锯齿状腺瘤被公认为结直肠癌的癌前病变,锯齿状通路被认为是可以独立发展成结直肠癌的重要通路,但目前对于锯齿状腺瘤恶变的相关危险因素还知之甚少。本文旨在分析锯齿状腺瘤在结直肠中的分布特点及潜在恶变因素。方法采用病例对照研究方法,回顾性收集2017年4月至2019年7月期间在中国医学科学院肿瘤医院行肠镜检查并经病理诊断为锯齿状腺瘤患者的临床资料,排除同时具有两种及以上病理类型病变的患者。总结锯齿状腺瘤的临床特征,并进行单因素和Logistic多因素回归分析,探讨锯齿状腺瘤发生恶变的影响因素。结果共在28730例行肠镜检查患者中,发现311例(1.08%)锯齿状腺瘤患者,共发现锯齿状腺瘤372枚。按WHO分类,无蒂锯齿状腺瘤/息肉22枚(5.9%),传统锯齿状腺瘤84枚(22.6%),未分类锯齿状腺瘤266枚(71.5%)。病理结果显示:无异型增生病变106枚(28.5%),低级别上皮内瘤变病变228枚(61.3%),高级别上皮内瘤变或癌变38枚(10.2%)。病变长径<10 mm有204枚(54.8%),≥10 mm有168枚(45.2%);病变位于左半结直肠238枚(64.0%),右半结肠134枚(36.0%)。内镜下大体分型:扁平型16枚(4.3%),无蒂型174枚(46.8%),亚蒂型117枚(31.5%),带蒂型59枚(15.9%)。窄带成像国际结直肠内镜(NICE)分型:Ⅰ型85枚(22.8%),Ⅱ型280枚(75.3%),Ⅲ型4枚(1.1%)。单因素分析显示,病变大小、病变位置、病变部位及不同WHO分类与结直肠锯齿状腺瘤发生恶变有关(均P<0.05);不同NICE分型的锯齿状腺瘤,其恶变率的差异亦有统计学差异(P=0.001)。多因素分析结果显示,病变长径≥10 mm(OR=6.699,95%CI:2.843~15.786)以及病变位于左半结直肠(OR=2.657,95%CI:1.042~6.775)是结直肠锯齿状腺瘤发生恶变的独立危险因素。结论锯齿状腺瘤主要位于左半结直肠,当病变长径≥10 mm或病变位于左半结直肠时,易发生恶变。  相似文献   
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