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   3250201篇
  免费   279068篇
  国内免费   13266篇
耳鼻咽喉   44878篇
儿科学   102051篇
妇产科学   84039篇
基础医学   519482篇
口腔科学   89007篇
临床医学   293109篇
内科学   561490篇
皮肤病学   90470篇
神经病学   275710篇
特种医学   130892篇
外国民族医学   225篇
外科学   508826篇
综合类   99990篇
现状与发展   23篇
一般理论   2189篇
预防医学   266465篇
眼科学   75448篇
药学   231211篇
  22篇
中国医学   9576篇
肿瘤学   157432篇
  2021年   49135篇
  2020年   35067篇
  2019年   57922篇
  2018年   70851篇
  2017年   53686篇
  2016年   59429篇
  2015年   73625篇
  2014年   107894篇
  2013年   173055篇
  2012年   88326篇
  2011年   87557篇
  2010年   115652篇
  2009年   120409篇
  2008年   74462篇
  2007年   76988篇
  2006年   88020篇
  2005年   83064篇
  2004年   84805篇
  2003年   75520篇
  2002年   65056篇
  2001年   106484篇
  2000年   98907篇
  1999年   96511篇
  1998年   59226篇
  1997年   57019篇
  1996年   54694篇
  1995年   55601篇
  1994年   49598篇
  1993年   46342篇
  1992年   67666篇
  1991年   64353篇
  1990年   61305篇
  1989年   60375篇
  1988年   55302篇
  1987年   53855篇
  1986年   51043篇
  1985年   50797篇
  1984年   46379篇
  1983年   42288篇
  1982年   40339篇
  1981年   37938篇
  1980年   35859篇
  1979年   37338篇
  1978年   33043篇
  1977年   30915篇
  1976年   27777篇
  1975年   26732篇
  1974年   26993篇
  1973年   26011篇
  1972年   24497篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
52.
目的 探讨人胶质母细胞瘤(GBM)组织微小核糖核酸-4516(miR-4516)的表达情况及其与病人预后的关系。方法选取 2015年 1月~2019年 5月手术切除的 GBM组织 89例和颅脑损伤内减压术切除的非肿瘤脑组织 35例为对照组,采用 qRT-PCR检测 miR-4516的表达水平,根据 miR-4516表达水平的中位数分为高表达和低表达。GBM病人术后随访 2年,记录生存情况。结果 GBM组织 miR-4516表达水平([ 5.32±1.75)]明显高于对照组([ 1.13±0.45);P<0.01]。术后 2年随访,42例(47.19%)生存,47例 47(52.81%)死亡。多因素 Cox回归分析显示,miR-4516高表达是 GBM生存预后病例的独立危险因素(P<0.05)。生存曲线分析显示 miR-4516高表达组 2年累积生存率(27.45%)明显低于低表达组(73.68%;P<0.001)。结论 GBM组织 miR-4516表达增高,其高表达是病人预后不良的危险因素。  相似文献   
53.
Medicine, Health Care and Philosophy - Clinical ethics consultants respond to a multitude of issues, ranging from the cognitive to the emotional. As such, ethics consultants must be prepared to...  相似文献   
54.
55.
56.
57.
The Dutch Drug Rediscovery Protocol (DRUP) and the Australian Cancer Molecular Screening and Therapeutic (MoST) Program are similar nonrandomized, multidrug, pan-cancer trial platforms that aim to identify signals of clinical activity of molecularly matched targeted therapies or immunotherapies outside their approved indications. Here, we report results for advanced or metastatic cancer patients with tumors harboring cyclin D-CDK4/6 pathway alterations treated with CDK4/6 inhibitors palbociclib or ribociclib. We included adult patients that had therapy-refractory solid malignancies with the following alterations: amplifications of CDK4, CDK6, CCND1, CCND2 or CCND3, or complete loss of CDKN2A or SMARCA4. Within MoST, all patients were treated with palbociclib, whereas in DRUP, palbociclib and ribociclib were assigned to different cohorts (defined by tumor type and alteration). The primary endpoint for this combined analysis was clinical benefit, defined as confirmed objective response or stable disease ≥16 weeks. We treated 139 patients with a broad variety of tumor types; 116 with palbociclib and 23 with ribociclib. In 112 evaluable patients, the objective response rate was 0% and clinical benefit rate at 16 weeks was 15%. Median progression-free survival was 4 months (95% CI: 3-5 months), and median overall survival 5 months (95% CI: 4-6 months). In conclusion, only limited clinical activity of palbociclib and ribociclib monotherapy in patients with pretreated cancers harboring cyclin D-CDK4/6 pathway alterations was observed. Our findings indicate that monotherapy use of palbociclib or ribociclib is not recommended and that merging data of two similar precision oncology trials is feasible.  相似文献   
58.
Hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer is defined by the presence of the estrogen receptor and/or the progesterone receptor and the absence of HER2 gene amplification. HR-positive/HER2-negative breast cancer accounts for 65%–70% of all breast cancers, and incidence increases with increasing age. Treatment varies by stage, and endocrine therapy is the mainstay of treatment in both early stage and late-stage disease. Combinations with cyclin-dependent kinase 4/6 inhibitors have reduced distant recurrence in the early stage setting and improved overall survival in the metastatic setting. Chemotherapy is used based on stage and tumor biology in the early stage setting and after endocrine resistance for advanced disease. New therapies, including novel endocrine agents and antibody-drug conjugates, are now changing the treatment landscape. With the availability of new treatment options, it is important to define the optimal sequence of treatment to maximize clinical benefit while minimizing toxicity. In this review, the authors first discuss the pathologic and molecular features of HR-positive/HER2-negative breast cancer and mechanisms of endocrine resistance. Then, they discuss current and emerging therapies for both early stage and metastatic HR-positive/HER2-negative breast cancer, including treatment algorithms based on current data.  相似文献   
59.
Prior studies have conflicting findings regarding the association between gastroesophageal reflux disease (GERD) and esophageal squamous cell carcinoma (ESCC). We examined this relationship in a prospective cohort in a region of high ESCC incidence. Baseline exposure data were collected from 50 045 individuals using in-person interviews at the time of cohort entry. Participants were followed until they developed cancer, died, or were lost to follow up. Participants with GERD symptoms were categorized into any GERD (heartburn or regurgitation), mixed symptoms, or heartburn alone. Multivariable Cox regression was used to assess the relationship between GERD symptom group and histologically confirmed ESCC. The model was adjusted for known risk factors for GERD and ESCC. 49 559 individuals were included in this study, of which 9005 had GERD symptoms. Over 13.0 years of median follow up, 290 individuals were diagnosed with ESCC. We found no association between any GERD and risk of ESCC (aHR 0.90, 95% CI: 0.66-1.24, P = .54). Similar findings were observed for the GERD symptom subtypes. Significant interactions between any GERD and sex (P = .013) as well as tobacco smoking (P = .028) were observed. In post-hoc analyses, GERD was associated with a decreased risk of ESCC in men (aHR 0.51, 95% CI: 0.27-0.98 P = .04) and in smokers (aHR 0.26, 95% CI: 0.08-0.83 P = .02). While there was little evidence for an overall association between GERD symptoms and ESCC risk, significant interactions with sex and smoking were observed. Men and smokers with GERD symptoms had a lower risk of ESCC development.  相似文献   
60.
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