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   6675篇
  免费   753篇
  国内免费   399篇
耳鼻咽喉   63篇
儿科学   64篇
妇产科学   90篇
基础医学   697篇
口腔科学   170篇
临床医学   862篇
内科学   833篇
皮肤病学   72篇
神经病学   292篇
特种医学   277篇
外国民族医学   2篇
外科学   624篇
综合类   1287篇
现状与发展   4篇
预防医学   448篇
眼科学   157篇
药学   868篇
  6篇
中国医学   503篇
肿瘤学   508篇
  2024年   47篇
  2023年   158篇
  2022年   373篇
  2021年   448篇
  2020年   339篇
  2019年   271篇
  2018年   263篇
  2017年   271篇
  2016年   227篇
  2015年   330篇
  2014年   370篇
  2013年   313篇
  2012年   443篇
  2011年   470篇
  2010年   292篇
  2009年   240篇
  2008年   288篇
  2007年   275篇
  2006年   318篇
  2005年   281篇
  2004年   183篇
  2003年   177篇
  2002年   169篇
  2001年   149篇
  2000年   172篇
  1999年   200篇
  1998年   109篇
  1997年   123篇
  1996年   87篇
  1995年   83篇
  1994年   67篇
  1993年   43篇
  1992年   54篇
  1991年   43篇
  1990年   30篇
  1989年   27篇
  1988年   21篇
  1987年   26篇
  1986年   15篇
  1985年   15篇
  1984年   3篇
  1983年   2篇
  1982年   3篇
  1981年   5篇
  1980年   1篇
  1979年   3篇
排序方式: 共有7827条查询结果,搜索用时 15 毫秒
31.
BackgroundTo investigate the association between single nucleotide polymorphisms (rs10078761, rs12696304, rs2853669, rs16847897, rs2736100, rs10069690) of telomerase gene (TERT) and the risk clinical benign prostatic hyperplasia (BPH) in a Chinese Han population of the Northwest region.MethodsA total of 150 BPH patients and 150 healthy older males from the northwest Chinese Han population were included in this study. The sample size for this unmatched case-control study was estimated by the look-up table method. Meanwhile, the general information and disease data of patients were collected. Age was only collected in healthy control subjects for statistical correction. Genotypes were detected using a multiplex PCR + ligase detection reaction (LDR). Typing results and clinical data were statistically analyzed using multiple linear regression and logistic regression. Pearson correlation was used for Hardy-Weinberg equilibrium.ResultsThe included population is in Hardy-Weinberg equilibrium. There was no significant association between SNP and the risk of BPH by correlation analysis. However, 4 haplotypes (TCTGGT, TCTGTC, TGCCTC, and TGTGTC) were identified as risk factors of BPH by haplotype analysis. The SNP rs2853669 is an independent risk factor for smooth muscle type of hyperplasia. Besides, rs2736100, rs10078761, and rs10069690 which are in linkage disequilibrium are associated with the severity of BPH.ConclusionsPolymorphism of the TERT gene determines the different disease development and pathological manifestations of BPH in the Chinese Han population the Northwest region.  相似文献   
32.
BackgroundTo evaluate to what degree preoperative urine white blood cell (WBC) and urine nitrite (NIT) values are predictive of postoperative infections following percutaneous nephrolithotomy (PCNL).MethodsA systematic literature search was performed of the PubMed, Embase, Cochrane Library, Wanfang Data, National Knowledge Infrastructure (CNKI), and China Science and Technology Journal Database (CSTJ or VIP) online databases to identify relevant studies that examined the predictive value of urine WBC or NIT as risk factors for post-PCNL infection, and the search was finished on February 28, 2020. Two independent reviewers screened the relevant studies, extracted necessary data from the eligible case-control studies (CCS), and assessed the quality of included studies through the Newcastle-Ottawa scale (NOS). RevMan 5.3 software and the Stata 16.0 software were used to complete the statistical analysis of data. Results are expressed as odds ratio (OR) with 95% confidence intervals (CIs).ResultsAccording to the statistical analysis of 12 eligible studies involving 6113 patients, positive urine WBC (WBC+: OR =3.86, 95% CI: 3.03–4.91, P<0.001) and positive NIT (NIT+: OR =7.81, 95% CI: 5.44–11.21, P<0.001) in preoperative tests were identified as independent risk factors for postoperative infections following PCNL.ConclusionsIn summary, as risk factors for postoperative infections, the presence of preoperative urine WBC+ and NIT+ should be evaluated as part of clinical procedure, in order to reduce infections of PCNL.  相似文献   
33.
BackgroundHuman papillomavirus (HPV) vaccine has been increasingly discussed in mainland China since its first approval in 2016. To date, nearly all studies assessing HPV vaccine perceptions and attitudes were implemented during pre-licensure period. Therefore, the nationwide post-marketing survey was conducted to update knowledge, attitudes and practice on HPV vaccine among general population in mainland China.MethodsParticipants aged 18–45 years living in mainland China were recruited in April 2019 by multi-stage non-randomized sampling. Sociodemographic factors, HPV and HPV vaccine related awareness, knowledge, attitudes, vaccine uptake and potential obstacles were assessed in questionnaires. Bivariate analysis and multivariate regression were used to identify disparity among subgroups with different sociodemographic characteristics.Results4,000 women (32.1 ± 7.81y) and 1,000 men (31.8 ± 7.96y) were included in final analysis. Less than one third of participants had heard of HPV (female: 31%; male: 22%) and HPV vaccine (female: 34%; male: 23%). Knowledge score was also unfavorable on HPV (female: 3 out of 13; male: 1.8 out of 13) and HPV vaccine (female: 3 out of 6; male: 2 out of 5). Only 3% females had been vaccinated three years after HPV licensure in China, although willingness to get vaccinated among those unvaccinated were high (mean willingness score ± SD: female: 3.3 ± 0.97; male: 3.0 ± 0.98). Industry of employment and household income were the major factors related to awareness and knowledge of vaccine, whereas HPV and HPV vaccine awareness were key influential factors for willingness. The main obstacles of vaccination were safety concerns, lack of knowledge, and high price of HPV vaccines.ConclusionsFindings highlight a lack of vaccine awareness, knowledge, and poor uptake in mainland China and underscore the necessity of health education campaigns. The identified priority groups, contents to be delivered and practical obstacles could furthermore provide insight into health education to reduce disparities and accelerate HPV vaccine roll-out in China.  相似文献   
34.
35.
Summary We studied the membrane effects of (1S,2S)-2-(2-[[3-2(benzimidazolyl) propyllmethylamino]ethyl)-6-fluoro-1,2,3,4-tetrahydro-l-isopropyl-2-naphthyl-methoxy-acetate dihydrochloride, Ro 40-5967, a new non-dihydropyridine (DHP) Ca2+ channel antagonist, on dog coronary and saphenous arterial vascular muscle cells using the whole-cell patch-clamp method. Long-lasting (L-type) inward currents in 20 mM Ba2+ were measured over a range of test potentials (300 ms) from –50 mV to + 90 mV from a holding potential of –80 mV in the presence of 1 M Bay k8644 (a DHP Ca2+ agonist). Ro 40-5967 caused a concentration-dependent suppression of Ca2+ channel currents in muscle cells from both arteries, with greater potency on coronary than saphenous arterial cells. The concentration of Ro 40-5967 which inhibited the magnitude of peak inward currents by 50% (IC50) was estimated to be 1 M (n = 5) in muscle cells from coronary artery and 10 M (n = 4) in saphenous artery. Ro 40-5967 (1 M) decreased the amplitude of the activation current-voltage relationship for coronary L-type Ca2+ channel currents over a wider range of membrane potentials than verapamil, diltiazem, or nifedipine. In contrast, block of Ca2+ channel currents in saphenous artery cells by 1 M Ro 40-5967 was only observed at command potentials positive to 0 mV. Ro 40-5967 (1 M) significantly shifted the voltage-inactivation curve downward by 40% in coronary (n = 4), but only by 18% in saphenous arterial muscle cells (n = 3). The non-parallel shift of the coronary artery inactivation curve suggests that pronounced resting channel block is a notable feature of Ro 40-5967. The marked inhibition of Ba2+ current by 1 M Ro 40-5967 in the inactivation protocol in coronary arterial muscle cells was found over the entire range of membrane holding potentials tested, while inhibition in the saphenous artery inactivation curve occurred only from holding potentials more positive than –40 mV. Therefore, Ro 40-5967 is unique: 1) in acting over a wider range of voltages, on both instantaneous and resting Ca2+ currents, than other Ca2+ antagonists; 2) in producing more significant resting state block; and 3) in acting with selectivity for coronary over saphenous arteries.This research was supported by National Institutes of Health grants HL38537, HL38645, and by F. Hoffmann-La Roche, Basel, Switzerland  相似文献   
36.
目的:建立凝血试验移动平均数质控法。方法:用移动平均数代替算术平均数,选择凝血验凝血酶原时间(PT),活化的部分凝血激酶时间和纤维蛋白原3个项目,比较两种质控方法,同时用标准血浆作为质控。结果:当用适当的移动平滑系数时,移动平均数质控法既能排除病人标本非随机必的干扰,又能很好地反映试验前因素的影响。结论 ;移动平均数空法可用于凝血试验的实验室质控。  相似文献   
37.
透析中的终末期肾脏病 (ESRD) ,有不少医师认为已属不可治性 ,只能靠透析或肾移植维持生存。但也有人报道ESRD在透析治疗后有一定可逆缓解率〔1 ,2〕,部分患者肾功能可能恢复至氮质血症期甚至更低水平 ,并能脱离透析 ,避免肾移植或使之延后。本文回顾性分析本院 3 52例透析的ESRD病例 ,对ESRD的可逆缓解率及相关因素作初步探讨。对象与方法一、病例来源1992年 5月~ 1999年 9月曾在本院行血透治疗的所有慢性肾功能不全病例 ,符合下述条件者入选 :①患者有尿毒症的临床表现 (消化道症状及贫血为必备条件 ) ,肌酐清除率Ccr…  相似文献   
38.
实验性局灶性脑缺血再灌注Fos蛋白的表达   总被引:1,自引:0,他引:1  
目的 探讨大鼠局灶性脑缺血再灌注Fos蛋白表达的意义及其机制。方法 采用免疫组化法观察Fos蛋白在大鼠局灶性脑缺血再灌注后皮层和基底节区的动态变化。结果 Fos蛋白在大脑中动脉阻断 1h后 ,随再灌注时间延长其分布不同。基底节区持续时间长 ,阳性细胞多 ,而皮层持续时间短 ,阳性细胞少。其中再灌注 90min ,Fos蛋白表达最显著。大脑中动脉供血中心区皮层几无表达。结论 Fos蛋白的表达与神经细胞存活密切相关 ,出现Fos蛋白表达的区域神经元易于耐受缺血性损害而存活 ,可能是神经细胞自我保护机制之一 ,Fos蛋白的表达存在扩散抑制  相似文献   
39.
溶栓后早期T波的变化与冠脉再通的关系   总被引:2,自引:0,他引:2  
目的 探讨急性心肌梗塞溶栓后早期T波的变化与闭塞冠脉再通的关系。方法 对80例接受静脉溶栓治疗的AMI患者进行前瞻性研究,根据溶栓后24小时内有无T波倒置分为两组。依据临床间接判断冠脉再通的标准观察两组血管再通情况。结果 T波倒置组与未倒置组血管再通率分别为93.1%和11.3%(P〈0.01)。结论 溶栓后早期T波倒置可作为判定梗塞相关血管再通的参考指标。  相似文献   
40.
Quinolin-2-one represents an important and valuable chemical motif that possesses a wide variety of biological activities; however, the anti-influenza activities of quinolin-2-one-containing compounds were rarely reported. Herein, we describe the screening and identification of 3-aryl-quinolin-2-one derivatives as a novel class of antiviral agents. The 3-aryl-quinolinone derivatives were synthesized via an efficient copper-catalyzed reaction cascade that we previously developed. Using this synthetic method, preliminary structure–activity relationships of this scaffold against the influenza A virus infection were systematically explored. The most potent compound 34 displayed IC50 values of 2.14 and 4.88 μM against the replication of H3N2 (A/HK/8/68) and H1N1 (A/WSN/33) strains, respectively, without apparent cytotoxicity on MDCK cells. We further demonstrated that 27 and 34 potently inhibited the plaque formation of the IAV, rendering this scaffold attractive for pursuing novel anti-influenza agents.  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