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   219717篇
  免费   12082篇
  国内免费   6434篇
耳鼻咽喉   2749篇
儿科学   8258篇
妇产科学   2983篇
基础医学   16777篇
口腔科学   4173篇
临床医学   26710篇
内科学   39703篇
皮肤病学   3023篇
神经病学   10842篇
特种医学   12144篇
外国民族医学   22篇
外科学   32872篇
综合类   19477篇
现状与发展   25篇
预防医学   14653篇
眼科学   4403篇
药学   23818篇
  80篇
中国医学   4488篇
肿瘤学   11033篇
  2023年   1873篇
  2022年   3656篇
  2021年   8886篇
  2020年   5158篇
  2019年   11088篇
  2018年   5708篇
  2017年   4891篇
  2016年   6889篇
  2015年   9729篇
  2014年   17789篇
  2013年   15509篇
  2012年   18825篇
  2011年   15603篇
  2010年   14399篇
  2009年   14015篇
  2008年   12593篇
  2007年   12671篇
  2006年   10666篇
  2005年   7009篇
  2004年   3484篇
  2003年   3057篇
  2002年   2476篇
  2001年   1951篇
  2000年   1770篇
  1999年   1094篇
  1998年   1485篇
  1997年   1355篇
  1996年   1143篇
  1995年   1216篇
  1994年   1174篇
  1993年   913篇
  1992年   1127篇
  1991年   1028篇
  1990年   1052篇
  1989年   1029篇
  1988年   949篇
  1987年   833篇
  1986年   678篇
  1985年   1594篇
  1984年   1748篇
  1983年   1259篇
  1982年   1349篇
  1981年   1333篇
  1980年   1151篇
  1979年   987篇
  1978年   763篇
  1977年   759篇
  1976年   662篇
  1975年   437篇
  1974年   457篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
61.
  1. Download : Download high-res image (246KB)
  2. Download : Download full-size image
  相似文献   
62.
63.
《Cirugía espa?ola》2022,100(11):709-717
ObjectiveMost evidence, including recent randomized controlled trials, analysing anal squamous cell carcinoma (SCC) do not consider immunocompromise patient population. The aim of this study was to compare clinical and oncological outcomes among immunocompetent and immunocompromised patients with anal squamous cell carcinoma.MethodMulticentric retrospective comparative study including 2 cohorts of consecutive patients, immunocompetent and immunocompromised, diagnosed with anal SCC. This study evaluated clinical characteristics, clinical response to radical chemoradiotherapy (CRT) and long-term oncological results including both local and distant recurrence, overall survival (OS) and disease-free survival (DFS).ResultsA total of 84 patients, 47 (55.6%) female, diagnosed with anal SCC from January 2012 to December 2017 were included, 22 (26%) and 62 (74%) patients in immunocompromised and immunocompetent groups respectively. Patients in immunocompromised group were significantly younger (53 vs. 61 years; P=0.001), with smaller tumoral size (P=0.044) and reported higher rates of substance abuse.including tobacco use (P=0.034) and parenteral drug consumption (P=0.001). No differences were found in administered therapies (P=301) neither in clinical response to chemoradiotherapy (83 vs. 100%). Moreover, similar 5-year OS (60 vs. 64%; P=0.756) and DFS (65 vs. 68%; P=0.338) were observed.ConclusionThe present study shows no significant differences in long-term oncological results among immunocompetent and immunocompromised patients diagnosed with anal SCC, with a similar oncologic treatment. This evidence might be explained due to the close monitoring and adequate therapeutic control of HIV positive patients.  相似文献   
64.
65.
66.
67.
68.
《Vaccine》2022,40(24):3320-3329
BackgroundCurrently, booster dose is needed after 2 doses of non-live COVID-19 vaccine. With limited resources and shortage of COVID-19 vaccines, intradermal(ID) administration might be a potential dose-sparing strategy.ObjectiveTo determine immunologic response and reactogenicity of ID ChAdOx1 nCoV-19 vaccine (AZD1222,Oxford/AstraZeneca) as a booster dose after completion of 2-dose CoronaVac(SV) in healthy adult.MethodsThis is a prospective cohort study of adult aged 18–59 years who received 2-dose SV at 14–35 days apart for more than 2 months. Participants received ID AZD1222 at fractional low dose(1×1010 viral particles,0.1 ml). Antibody responses were evaluated by surrogate virus neutralization test(sVNT) against delta variant and wild type, and anti-spike-receptor-binding-domain immunoglobulin G(anti-S-RBD IgG) at prior, day14, 28, 90, and 180 post booster. Solicited reactogenicity was collected for 7 days post-booster. Primary endpoint was the differences of sVNT against delta strain ≥ 80% inhibition at day14 and 90 compared with the parallel cohort study of 0.5-ml intramuscular(IM) route.ResultsFrom August2021, 100 adults with median age of 46 years(IQR 41–52) participated. Prior to booster, geometric mean(GM) of sVNT against delta strain was 22.4% inhibition(95 %CI 18.7–26.9) and of anti-S-RBD IgG was 109.3 BAU/ml(95.4–125.1). Post ID booster, GMs of sVNT against delta strain were 95.5% inhibition (95%CI 94.2–96.8) at day14, 73.1% inhibition (66.7–80.2) at day90, and 22.7% inhibition (14.9–34.6) at day180. The differences of proportion of participants achieving sVNT against delta strain ≥ 80% inhibition in ID recipients versus IM were + 4.2% (95 %CI -2.0to10.5) at day14, and ?37.3%(-54.2to-20.3) at day90. Anti-S-RBD IgG GMs were 2037.1 BAU/ml (95%CI 1770.9–2343.2) at day14 and 744.6 BAU/ml(650.1–852.9) at day90, respectively. Geometric mean ratios(GMRs) of anti-S-RBD IgG were 0.99(0.83–1.20) at day14, and 0.82(0.66–1.02) at day90. Only 18% reported feverish, compared with 37% of IM (p = 0.003). Common reactogenicity was erythema at injection site(53%) while 7% reported blister.ConclusionLow-dose ID AZD1222 booster enhanced lower neutralizing antibodies at 3 months compared with IM route. Less systemic reactogenicity occurred, but higher local reactogenicity.  相似文献   
69.
BackgroundWe assessed whether or not covalently closed circular DNA (cccDNA) levels in the background liver influence the recurrence of hepatocellular carcinoma (HCC) in patients with resolved hepatitis B virus (HBV) infection.MethodsAmong 425 patients who underwent initial hepatectomy for HCC between 2010 and 2018, a retrospective review was performed in 44 with resolved HBV infection. The clinicopathologic characteristics were analyzed for correlation with tumor recurrence. The HBV cccDNA levels were tested via a droplet digital polymerase chain reaction assay.ResultsHBV cccDNA was detected in 27 of 44 patients (61%), and the median level was 1.0 copies/1000 ng (range, 0-931.3 copies/1000 ng). Anti-HBc ≥8.9 S/CO was associated with cccDNA detection (odds ratio, 11.08; 95% confidence interval [95% CI], 2.48-49.46; P = 0.002). Twenty-eight patients (64%) developed HCC recurrence after hepatectomy. The overall 3- and 5-year recurrence-free survival rates were 45.7% and 34.3%, respectively.19 HBV cccDNA levels was not significantly associated with HCC recurrence, while the presence of multiple tumors was an independent risk fact or (hazard ratio, 6.53; 95% CI, 2.48-17.19; P < 0.001.ConclusionHBV cccDNA levels did not influence HCC recurrence after hepatectomy. Anti-HBc levels may be used as a surrogate marker for cccDNA.  相似文献   
70.
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