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   2329180篇
  免费   165315篇
  国内免费   5217篇
耳鼻咽喉   32039篇
儿科学   76735篇
妇产科学   66992篇
基础医学   328645篇
口腔科学   65311篇
临床医学   199927篇
内科学   457722篇
皮肤病学   53812篇
神经病学   186896篇
特种医学   91851篇
外国民族医学   817篇
外科学   350952篇
综合类   49006篇
一般理论   723篇
预防医学   186794篇
眼科学   54005篇
药学   166693篇
  3篇
中国医学   4986篇
肿瘤学   125803篇
  2019年   18246篇
  2018年   29195篇
  2017年   23003篇
  2016年   24182篇
  2015年   27941篇
  2014年   37199篇
  2013年   53892篇
  2012年   78888篇
  2011年   79258篇
  2010年   45704篇
  2009年   44029篇
  2008年   71158篇
  2007年   75940篇
  2006年   76345篇
  2005年   81396篇
  2004年   79590篇
  2003年   72599篇
  2002年   66468篇
  2001年   105323篇
  2000年   106502篇
  1999年   91301篇
  1998年   23579篇
  1997年   20890篇
  1996年   20973篇
  1995年   21018篇
  1994年   19382篇
  1993年   18192篇
  1992年   71599篇
  1991年   68939篇
  1990年   67294篇
  1989年   64262篇
  1988年   59415篇
  1987年   58154篇
  1986年   55036篇
  1985年   52245篇
  1984年   39254篇
  1983年   33188篇
  1982年   19414篇
  1979年   36107篇
  1978年   25092篇
  1977年   20874篇
  1976年   19629篇
  1975年   21648篇
  1974年   26195篇
  1973年   25140篇
  1972年   23822篇
  1971年   21963篇
  1970年   20987篇
  1969年   19746篇
  1968年   18718篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Many environmental risk factors for hepatobiliary cancers are known but whether they are associated with specific cancer types is unclear. We present here a novel approach of assessing standardized incidence ratios (SIRs) of previously diagnosed comorbidities for hepatocellular carcinoma (HCC), gallbladder cancer (GBC), cholangiocarcinoma (CCA) and ampullary cancer. The 13 comorbidities included alcohol and nonalcohol related liver disease, chronic obstructive pulmonary disease, gallstone disease, viral and other kinds of hepatitis, infection of bile ducts, hepatic and other autoimmune diseases, obesity and diabetes. Patients were identified from the Swedish Inpatient Register from 1987 to 2018, and their cancers were followed from 1997 onwards. SIRs for HCC were 80 to 100 in men and women diagnosed with hepatitis C virus and they were also >10 in patients diagnosed with hepatitis B virus, other kind of hepatitis, hepatic autoimmune disease and nonalcohol related liver disease. Many of these risks, as well as alcohol related liver disease, were either specific to HCC or were shared with intrahepatic CCA. For GBC, CCA and ampullary cancer infection of bile ducts was the main risk factor. Gallstone disease, nonhepatic autoimmune diseases and diabetes were associated with all hepatobiliary cancers. The limitations of the study include inability to cover some rare risk factors and limited follow-up time. Many of the considered comorbidities are characterized by chronic inflammation and/or overt immune disturbance in autoimmune diseases. The results suggest that local chronic inflammation and a related immune disturbance is the carcinogenic trigger for all these cancers.  相似文献   
2.
The analysis of mismatch repair proteins in solid tissue is the standard of care (SoC) for the microsatellite instability (MSI) characterization in endometrial cancer (EC). Uterine aspirates (UAs) or circulating-DNA (cfDNA) samples capture the intratumor heterogeneity and provide a more comprehensive and dynamic molecular diagnosis. Thus, MSI analysis by droplet-digital PCR (ddPCR) in UAs and cfDNA can provide a reliable tool to characterize and follow-up the disease. The UAs, paraffin-embedded tumor tissue (FFPE) and longitudinal plasma samples from a cohort of 90 EC patients were analyzed using ddPCR panel and compared to the SoC. A high concordance (96.67%) was obtained between the analysis of MSI markers in UAs and the SoC. Three discordant cases were validated as unstable by ddPCR on FFPE samples. Besides, a good overall concordance (70.27%) was obtained when comparing the performance of the ddPCR assay on UAs and cfDNA in high-risk tumors. Importantly, our results also evidenced the value of MSI analysis to monitor the disease evolution. MSI evaluation in minimally invasive samples shows great accuracy and sensitivity and provides a valuable tool for the molecular characterization and follow-up of endometrial tumors, opening new opportunities for personalized management of EC.  相似文献   
3.
AIDS and Behavior - Although misperceived norms often drive personal health behaviors, we do not know about this phenomenon in the context of antiretroviral therapy (ART) adherence. We conducted a...  相似文献   
4.
Coates  Laura C.  Mease  Philip  Kronbergs  Andris  Helt  Cameron  Sandoval  David  Park  So Young  Combe  Bernard  Nash  Peter  Deodhar  Atul 《Clinical rheumatology》2022,41(10):3035-3047
Clinical Rheumatology - To evaluate the three-year efficacy and safety of ixekizumab with and without concomitant conventional synthetic disease-modifying antirheumatic drug (csDMARD) use in...  相似文献   
5.
Prevention Science - There is evidence that universal school-based mindfulness training (SBMT) can have positive effects for young people. However, it is unknown who benefits most from such...  相似文献   
6.
Objective: Nucleolar organizer regions (NORs) are DNA coils that transcribe to ribosomal RNA. The NOR-associated protein, termed argyrophilic NOR (AgNOR), was visible within the nucleus by staining with silver nitrate examination via the light microscope. AgNOR counting is a proliferation marker and may help in the diagnosis and prognosis of various neoplastic lesions. Aneuploidy (abnormal DNA content) can predict the progression, survival and prognosis of the tumors. The aim of this study was to evaluate the role of AgNORs, DNA ploidy status, and total S-phase fraction (TSPF) as prognostic parameters in malignant salivary gland tumors (MSGTs). Methods: The current study is a retrospective study on a cohort of MSGTs (N=47), to assess AgNORs using Silver Nitrate stain, DNA index (DI), and TSPF using flow cytometry (FCM). Data including tumor size and site, lymphovascular invasion (LVI), lymph node metastasis (LNM) were collected. Results: The AgNORs count was statistically significant with MSGT type. DI was found to have a significant association with tumor site, tumor size and MSGT type. In addition, TSPF was found to be significantly associated with LVI. A moderate positive correlation was noted between AgNORs count and TSPF. LNM, tumor site, high AgNORs and low DI were all associated with short disease-free survival (DFS) and poor overall survival (OS). Conclusion: The present study revealed that high AgNORs count, DNA aneuploidy and TSPF had a poor influence on MSGTs prognosis.  相似文献   
7.
8.
9.
BackgroundResearch into oral health care for older people has shown that dental care in general decreases with increasing age and frailty and, therefore, oral health care provision may be complex. The aim of this study is to identify the oral health care dentists provide to community-dwelling older people and which barriers they experience in doing this.MethodsIn this cross-sectional study, a representative sample of dentists in the Netherlands was asked to prospectively select one older patient and describe this patient using a specially developed registration form; the patient was requested to fill out a questionnaire. The relationship between experienced barriers in providing oral health care to older patients and characteristics of the dentists and the patients was studied by means univariate and multivariate logistic regression analysis.ResultsIn total, 923 dentists were asked to participate in the study. Data were available for 39.4% dentist–patient pairs. In most cases (87.4%), oral health care was focussed on conservation of the dentition. In all, 14.0% of the dentists experienced barriers in providing oral health care for older people. Some patient factors increase the risk of experiencing barriers, eg, the more difficult behaviour of older patients and the greater disease burden.ConclusionsOral health care was mostly focussed on conservation of the dentition, and dentists especially experience barriers in oral health provision to older patients if they are already frail.  相似文献   
10.
Clinical Oral Investigations - To validate a questionnaire for the identification of factors associated with erosive tooth wear (ETW) in adolescents. Based on previous questionnaires, a 73-question...  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