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   41730篇
  免费   4576篇
  国内免费   834篇
耳鼻咽喉   302篇
儿科学   875篇
妇产科学   547篇
基础医学   3117篇
口腔科学   1494篇
临床医学   4086篇
内科学   5306篇
皮肤病学   466篇
神经病学   3250篇
特种医学   1258篇
外国民族医学   3篇
外科学   3348篇
综合类   4733篇
现状与发展   5篇
一般理论   2篇
预防医学   7073篇
眼科学   566篇
药学   3276篇
  25篇
中国医学   4409篇
肿瘤学   2999篇
  2024年   37篇
  2023年   926篇
  2022年   907篇
  2021年   1634篇
  2020年   1736篇
  2019年   1697篇
  2018年   1686篇
  2017年   1611篇
  2016年   1470篇
  2015年   1313篇
  2014年   3095篇
  2013年   3136篇
  2012年   2504篇
  2011年   2663篇
  2010年   2034篇
  2009年   1951篇
  2008年   2209篇
  2007年   2274篇
  2006年   2034篇
  2005年   1704篇
  2004年   1403篇
  2003年   1338篇
  2002年   1029篇
  2001年   955篇
  2000年   752篇
  1999年   647篇
  1998年   445篇
  1997年   463篇
  1996年   357篇
  1995年   412篇
  1994年   357篇
  1993年   297篇
  1992年   297篇
  1991年   261篇
  1990年   220篇
  1989年   203篇
  1988年   193篇
  1987年   154篇
  1986年   122篇
  1985年   114篇
  1984年   100篇
  1983年   67篇
  1982年   65篇
  1981年   61篇
  1980年   57篇
  1979年   32篇
  1978年   29篇
  1977年   26篇
  1976年   18篇
  1975年   18篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
BackgroundColorectal cancer (CRC) is the primary cause of cancer-related deaths worldwide. Identification of new CRC biomarkers is imperative to improve the prognosis and development of therapies against the disease. LAGE3 (L Antigen Family Member 3) functions as a tRNA modifier, although its potential role in CRC has not been fully elucidated.MethodsRNA-seq matrix and corresponding clinical information were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, then subjected to survival, enrichment, and tumor microenvironment analyses using packages implemented in R.ResultsWe found that LAGE3 was upregulated and significantly correlating with poor prognosis in multiple CRC cohorts. Additionally, multivariate Cox regression analysis revealed that LAGE3 was an independent prognostic factor in patients with CRC, whereas functional enrichment analysis indicated that it could regulate protein targeting, tRNA processing, and the PD-1/PD-L1 checkpoint pathway. Furthermore, CIBERSORT analysis indicated a negative relationship between LAGE3 and levels of infiltration for multiple immune cells, especially CD8 + T cells in CRC. Particularly, LAGE3 expression was inversely correlated with the expression of immune checkpoints as well as that of various immune cell types of signature genes.ConclusionCollectively, our results indicate that high LAGE3 expression correlates with adverse prognosis and poor immune infiltration in CRC patients.  相似文献   
32.
Incidence of human papillomavirus (HPV) attributable oropharyngeal cancers (OPCs) has been increasing globally, especially among men in high-income countries. There is a lack of studies comparing oral HPV prevalence by age and country among healthy men. The purpose of our study was to assess oral HPV prevalence by country and age. Participants of the HPV Infection in Men Study (HIM), a cohort of 3,098 healthy men from São Paulo, Brazil, Cuernavaca, Mexico and Tampa, USA, were studied. Oral HPV prevalence and type distribution were assessed using the SPF10 PCR-DEIA-LiPA25 system. The prevalence of any HPV in Brazil, Mexico and the US was 8.7% (95% CI: 7.1%, 10.4%), 10.0% (95% CI: 8.3%, 12.1%) and 7.6% (95% CI: 5.9%, 9.5%), respectively, while the prevalence of high-risk HPV was 5.3% (95% CI: 4.1%, 6.7%), 7.3% (95% CI: 5.7%, 9.0%) and 5.4% (95% CI: 4.0%, 7.0%), respectively. No significant differences in prevalence of grouped HPV types were observed by country despite significant differences in sexual behaviors. However, the age-specific prevalence of oral HPV differed by country. Brazilian (6.0% [95% CI: 3.4%, 9.7%]) and Mexican (9.2% [95% CI: 5.6%, 14.0%]) participants had peak high-risk HPV prevalence among men aged 41–50 years whereas the US participants had peak prevalence at ages 31–40 years (11.0% [95% CI: 6.4%, 17.3%]). In conclusion, oral HPV prevalence was low with no difference in overall prevalence observed by country. Factors associated with the differences in oral HPV age-patterning by country and sexual orientation require further study.  相似文献   
33.
目的观察祛寒逐风合剂联合西医常规疗法对膝骨关节炎风寒痹阻证的临床疗效,以及对关节症状及相关实验室指标的影响。方法采用随机数字表法将94例膝骨关节炎风寒痹阻证患者分为观察组和对照组各47例。对照组采用常规药物疗法+康复训练,观察组在对照组基础上予祛寒逐风合剂,每次50m L,每日3次,口服。2组均连续治疗2周。比较2组临床疗效,观察2组治疗前后美国西大略湖和麦克马斯特大学骨关节炎指数(WOMAC)评分、视觉模拟评分法(VAS)评分、压痛指数、中医症状评分,白细胞介素(IL)-1β、IL-6、血管内皮生长因子(VEGF)、肿瘤坏死因子(TNF)-α、骨钙素、抗酒石酸盐酸性磷酸酶异构体(TRACP)-5b、骨特异性碱性磷酸酶(BALP)、纤维蛋白原、红细胞沉降率和红细胞聚集指数,对2组进行安全性评价。结果观察组总有效率为89.36%(42/47),对照组为74.47%(35/47),观察组明显优于对照组(P<0.05)。与本组治疗前比较,2组治疗后WOMAC评分、VAS评分、压痛指数、中医症状评分明显下降(P<0.05);2组治疗后比较,观察组WOMAC评分、VAS评分、压痛指数、中医症状评分明显低于对照组(P<0.05)。与本组治疗前比较,2组治疗后IL-1β、IL-6、TNF-α、VEGF、TRACP-5b水平明显下降,骨钙素、BALP水平明显升高(P<0.05);2组治疗后比较,观察组IL-1β、IL-6、TNF-α、VEGF、TRACP-5b水平明显低于对照组,骨钙素、BALP水平明显高于对照组(P<0.05)。与本组治疗前比较,观察组治疗后纤维蛋白原、红细胞沉降率、红细胞聚集指数明显下降(P<0.05);2组治疗后比较,观察组血液流变学各项指标明显低于对照组(P<0.05)。2组均未发生不良反应。结论祛寒逐风合剂联合西医常规疗法治疗膝骨关节炎风寒痹阻证患者疗效较好,可明显改善关节症状及相关实验室指标。  相似文献   
34.
胃息肉在消化道息肉中最常见,疾病早期多无明显症状,即使有临床症状也无特异性,主要表现为上腹疼痛和腹胀等症,极易造成漏治和误治,在很大程度上影响患者的生活质量。于春泉主任总结多年临床经验,在治疗胃息肉方面有独到的见解,以气血同治为治疗法则,通过补气、行气、活血和养血等治法扶正祛邪,恢复脏腑气血阴阳动态平衡,标本兼顾,临床效果可观。  相似文献   
35.
ABSTRACT

Objectives: This study aimed to compare the risk of fractures, acute myocardial infarction, atrial fibrillation, and ventricular arrhythmia among Danish citizens aged ≥ 65 which were new users of promethazine or domperidone, triazolam, loratadine, and betahistine. Secondly, the study aimed to perform a risk stratification to identify the most relevant predictors for the study outcomes.

Methods: The study period was 01/01/2015 to 31/12/2016. The data sources were the Danish registers. Each patient was followed for 90 days. A logistic regression model was used to compute the unadjusted and adjusted odds ratios (OR), and a conditional inference tree was used to identify the most relevant predictors for the study outcomes.

Results: Promethazine had a higher risk of hospitalization for atrial fibrillation than loratadine and betahistine (OR 1.58; 95% CI 1.07–2.63 and OR 3.22; 95% CI 1.69–7.14, respectively). For fractures, acute myocardial infarction, and ventricular arrhythmia hospitalizations, no statistically significant differences were found among drugs under investigation. The medical history of cardiac arrhythmia (OR 4.14; 95% CI 2.94–5.78, p < 0.0001) was the most relevant predictor for atrial fibrillation hospitalizations.

Conclusion: This study found an increased risk of atrial fibrillation hospitalization among promethazine users, and the risk was higher among patients with prior cardiac arrhythmia.  相似文献   
36.
Coronavirus disease 2019 (COVID?19) is a newly emerging infectious disease.After its outbreak, researchersstarted a large number of clinical interventional studies, using a variety of interventions to study the different types of COVID?19 cases. In this article, we searched the websites of Chinese Clinical Trial Registry, ClinicalTrials.gov, etc., to study the publicly registered research information. Through the classification and summary of interventional methods, evaluation indicators, research design, etc., this article provided readers with the outline of clinical research about COVID?19, and looked forward to the scientificity, feasibility, and future evidence of the clinical researches.  相似文献   
37.
监测数据统计分析模型在生态学研究中的应用   总被引:1,自引:1,他引:0       下载免费PDF全文
近年来,环境监测、疾病监测等各种监测网络不断健全,监测系统成为开展生态学研究的重要数据来源。监测数据类型包括了横断面数据、时间序列数据和面板数据,涉及暴露、结局和混杂3个维度。针对该数据的信息属性和结构特点,相关统计学方法逐渐发展完善,出现了一些新的方法、模型。基于数据的时空属性,本文对监测数据在生态学研究中常用模型的原理、适用条件及优劣进行了综述。  相似文献   
38.
The relationship between hepatitis B virus (HBV) and nonhepatocellular cancers remains inconclusive. This large case-control study aimed to assess the associations between HBV infection status and multiple cancers. Cases (n = 50 392) and controls (n = 11 361) were consecutively recruited from 2008 to 2016 at the First Affiliated Hospital of Nanjing Medical University. Multivariable adjusted odds ratios (aORs) and 95% confidence intervals (95% CIs) were estimated using logistic regression by adjusting age and gender. A meta-analysis based on published studies was also performed to verify the associations. Of these, 12.1% of cases and 5.5% of controls were hepatitis B surface antigen (HBsAg) seropositive. We observed significant associations between HBsAg seropositivity and esophagus cancer (aOR [95% CI] = 1.32 [1.13-1.54]), stomach cancer (1.46 [1.30-1.65]), hepatocellular carcinoma (HCC; 39.11 [35.08-43.59]), intrahepatic and extrahepatic bile duct carcinoma (ICC and ECC; 3.83 [2.58-5.67] and 1.72 [1.28-2.31]), pancreatic cancer (PaC; 1.37 [1.13-1.65]), non-Hodgkin lymphoma (NHL; 1.88 [1.61-2.20]) and leukemia (11.48 [4.05-32.56]). Additionally, compared to participants with HBsAg−/anti-HBs−/anti-HBc−, participants with HBsAg−/anti-HBs−/anti-HBc+, indicating past HBV-infected, had an increased risk of esophagus cancer (aOR [95% CI] = 1.46 [1.24-1.73]), stomach cancer (1.20 [1.04-1.39]), HCC (4.80 [3.95-5.84]) and leukemia (15.62 [2.05-119.17]). Then the overall meta-analysis also verified that HBsAg seropositivity was significantly associated with stomach cancer (OR [95% CI] = 1.23 [1.14-1.33]), ICC (4.05 [2.78-5.90]), ECC (1.73 [1.30-2.30]), PaC (1.26 [1.09-1.46]), NHL (1.95 [1.55-2.44]) and leukemia (1.54 [1.26-1.88]). In conclusion, both our case-control study and meta-analysis confirmed the significant association of HBsAg seropositivity with stomach cancer, ICC, ECC, PaC, NHL and leukemia. Of note, our findings also suggested that the risk of stomach cancer elevated for people whoever exposed to HBV.  相似文献   
39.
目的对非布司他治疗慢性肾脏病伴高尿酸血症的临床效果进行研究.方法46例慢性肾脏病伴高尿酸血症患者,随机分为常规组与科研组,各23例.常规组采用别嘌醇片治疗,科研组采用非布司他治疗.比较两组治疗前后尿酸、血尿素氮、血肌酐水平及药物不良反应发生情况.结果治疗后,科研组血尿酸、血尿素氮及血肌酐水平分别为(290.92±59.12)μmmol/L、(13.06±5.23)mmol/L、(269.12±52.42)μmmol/L,低于常规组的(520.81±60.14)μmmol/L、(15.81±5.73)mmol/L、(293.34±56.18)μmmol/L,差异有统计学意义(P<0.05).科研组药物不良反应发生率4.35%低于常规组的43.48%,差异有统计学意义(P<0.05).结论慢性肾脏病伴高尿酸血症采用非布司他进行治疗,能够明显降低患者的尿酸、血尿素氮、血肌酐水平,不良反应少,安全性高,疗效确切.  相似文献   
40.
Objective: Our aim was to study the association between early-life factors and the development of endometriosis.

Methods: This case–control study included 440 women with surgically confirmed endometriosis (cases) and 880 women without endometriosis (controls). Information on early-life factors was ascertained retrospectively by in-person interviews with participants and their mothers. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between endometriosis and maternal and paternal characteristics and foetal and infant exposures were estimated using unconditional logistic regression, adjusting for frequency matching and confounding variables.

Results: We observed that women who were not breastfed as infants had twice the risk of endometriosis compared with women who were breastfed (adjusted OR 2.0; 95% CI 1.6, 4.5). Our data suggested an increased endometriosis risk with neonatal vaginal bleeding (adjusted OR 1.9; 95% CI 1.2, 4.3) and paternal smoking (adjusted OR 1.8; 95% CI 1.1, 4.9). Although the CIs included the null hypothesis value, caesarean section (adjusted OR 1.7; 95% CI 1.0, 3.5) and prematurity (adjusted OR 1.4; 95% CI 0.8, 3.7) were probably associated with the incidence of endometriosis.

Conclusions: Some early-life factors including breastfeeding, neonatal vaginal bleeding and paternal smoking were associated with subsequent, surgically confirmed endometriosis in this cohort of Chinese women.  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