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   110714篇
  免费   8582篇
  国内免费   5065篇
耳鼻咽喉   255篇
儿科学   3287篇
妇产科学   688篇
基础医学   7643篇
口腔科学   281篇
临床医学   9316篇
内科学   62938篇
皮肤病学   434篇
神经病学   2091篇
特种医学   2285篇
外国民族医学   15篇
外科学   8963篇
综合类   7014篇
现状与发展   16篇
一般理论   4篇
预防医学   3809篇
眼科学   140篇
药学   6895篇
  71篇
中国医学   510篇
肿瘤学   7706篇
  2024年   123篇
  2023年   3132篇
  2022年   4884篇
  2021年   5807篇
  2020年   5109篇
  2019年   3711篇
  2018年   4569篇
  2017年   4016篇
  2016年   3959篇
  2015年   4300篇
  2014年   8037篇
  2013年   7352篇
  2012年   7069篇
  2011年   7095篇
  2010年   6035篇
  2009年   5337篇
  2008年   4787篇
  2007年   4991篇
  2006年   4490篇
  2005年   3899篇
  2004年   3103篇
  2003年   3001篇
  2002年   2647篇
  2001年   2376篇
  2000年   1913篇
  1999年   1709篇
  1998年   1083篇
  1997年   710篇
  1996年   801篇
  1995年   838篇
  1994年   648篇
  1993年   596篇
  1992年   687篇
  1991年   643篇
  1990年   664篇
  1989年   600篇
  1988年   560篇
  1987年   419篇
  1986年   313篇
  1985年   249篇
  1984年   222篇
  1983年   166篇
  1982年   196篇
  1981年   153篇
  1980年   137篇
  1979年   139篇
  1978年   153篇
  1977年   143篇
  1976年   104篇
  1975年   103篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
21.
《Mucosal immunology》2021,14(3):691-702
Plectin, a highly versatile cytolinker protein, provides tissues with mechanical stability through the integration of intermediate filaments (IFs) with cell junctions. Here, we hypothesize that plectin-controlled cytoarchitecture is a critical determinant of the intestinal barrier function and homeostasis. Mice lacking plectin in an intestinal epithelial cell (IEC; PleΔIEC) spontaneously developed colitis characterized by extensive detachment of IECs from the basement membrane (BM), increased intestinal permeability, and inflammatory lesions. Moreover, plectin expression was reduced in the colons of ulcerative colitis (UC) patients and negatively correlated with the severity of colitis. Mechanistically, plectin deficiency in IECs led to aberrant keratin filament (KF) network organization and the formation of dysfunctional hemidesmosomes (HDs) and intercellular junctions. In addition, the hemidesmosomal α6β4 integrin (Itg) receptor showed attenuated association with KFs, and protein profiling revealed prominent downregulation of junctional constituents. Consistent with the effects of plectin loss in the intestinal epithelium, plectin-deficient IECs exhibited remarkably reduced mechanical stability and limited adhesion capacity in vitro. Feeding mice with a low-residue liquid diet that reduced mechanical stress and antibiotic treatment successfully mitigated epithelial damage in the PleΔIEC colon.  相似文献   
22.
23.
24.
25.
Background:We aim to evaluate the efficiency of Raman spectroscopy (RS) in diagnosing suspected patients with intrahepatic cholangiocarcinoma (ICC), manifested by diagnostic sensitivity, specificity, and accuracy.Methods:We will research widely the articles concerning the use of RS in ICC through authenticated database including PubMed/Medline, EMBASE, Web of Science, Ovid, Web of Knowledge, Cochrane Library, and CNKI between January 2012 and November 2020, retrieving at least 1500 spectra with strict criteria. This study will be carried out in accordance to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We are going to summarize the test performance using random effects models.Results:Based on the pooled sensitivity, specificity, and diagnostic accuracy, we intend to provide the relative diagnostic efficiency in ICC through RS.Conclusion:Through this systematic review and meta-analysis, we intend to provide the pooled sensitivity, specificity and diagnostic accuracy of RS in the diagnosis of suspected ICC. Other parameters like positive likelihood ratios (LR), negative LR, diagnostic odds ratio (DOR), and area under curve (AUC) of the summary receiver operating characteristics (SROC) curve will also be calculated and related figures will be drawn to help illustrate the efficacy of RS in the diagnosis of ICC.  相似文献   
26.
27.
28.
《Digestive and liver disease》2022,54(11):1486-1493
BackgroundCold snare polypectomy (CSP) is a promising technique for the removal of sessile serrated polyps (SSPs) ≥ 10 mm. However, the efficacy and safety of this technique remain undetermined.AimsWe aimed to comprehensively evaluate the efficacy and safety of CSP for SSPs ≥ 10 mm.MethodsPubMed, EMBASE, Web of Science and Cochrane Library were searched up to January 2021.ResultsA total of 10 studies consisting of 1727 SSPs (range, 10–40 mm) from 1021 patients were included. The overall rates of technical success, adverse events (AEs) and residual SSPs were 100%, 0.7% and 2.9%, respectively. Subgroup analysis showed that the rates of technical success and AEs were comparable between CSP and cold endoscopic mucosal resection (EMR) (99.9% vs. 100% and 1.3% vs. 0.5%, respectively), between the proximal and distal colon (100% vs. 99.9% and 0.3% vs. 0, respectively), and between polyps of 10–19 mm and ≥20 mm (99.8% vs. 100% and 0.9% vs. 0, respectively). However, subgroup analysis showed that the rate of residual SSPs was slightly lower in CSP compared with cold EMR (1.3% vs. 3.9%), as well as in polyps of 10–19 mm compared with those ≥20 mm (3.1% vs. 4.7%).ConclusionCSP was an effective and safe technique for removing SSPs ≥ 10 mm.  相似文献   
29.
30.
Recent epidemiological studies suggested that proton pump inhibitor (PPI) use was associated with an increased risk of biliary tract cancer (BTC), however, confounders were not adequately controlled. Our study aimed to evaluate PPI use and subsequent risk of BTC and its subtypes in three well-established cohorts. We conducted a pooled analysis of the subjects free of cancers in UK Biobank (n = 463 643), Nurses' Health Study (NHS, n = 80 235) and NHS II (n = 95 869). Propensity score weighted Cox models were used to estimate marginal HRs of PPIs use on BTC risk, accounting for potential confounders. We documented 284 BTC cases in UK Biobank (median follow-up: 7.6 years), and 91 cases in NHS and NHS II cohorts (median follow-up: 15.8 years). In UK biobank, PPI users had a 96% higher risk of BTC compared to nonusers in crude model (HR 1.96, 95% CI 1.44-2.66), but the effect was attenuated to null after adjusting for potential confounders (HR 0.95, 95% CI 0.60-1.49). PPI use was not associated with risk of BTC in the pooled analysis of three cohorts (HR 0.93, 95% CI 0.60-1.43). We also observed no associations between PPI use with risk of intrahepatic (HR 1.00, 95% CI 0.49-2.04), extrahepatic bile duct (HR 1.09, 95% CI 0.52-2.27) and gallbladder cancers (HR 0.66, 95% CI 0.26-1.66) in UK Biobank. In summary, regular use of PPIs was not associated with the risk of BTC and its subtypes.  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