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   5264040篇
  免费   407136篇
  国内免费   17374篇
耳鼻咽喉   74306篇
儿科学   165303篇
妇产科学   139169篇
基础医学   782518篇
口腔科学   150729篇
临床医学   479206篇
内科学   964815篇
皮肤病学   123697篇
神经病学   438902篇
特种医学   203847篇
外国民族医学   1104篇
外科学   787229篇
综合类   149878篇
现状与发展   23篇
一般理论   2889篇
预防医学   446612篇
眼科学   126731篇
药学   376188篇
  28篇
中国医学   14450篇
肿瘤学   260926篇
  2021年   60133篇
  2019年   62333篇
  2018年   80361篇
  2017年   61274篇
  2016年   68196篇
  2015年   80661篇
  2014年   116474篇
  2013年   183494篇
  2012年   155380篇
  2011年   164635篇
  2010年   137275篇
  2009年   135670篇
  2008年   147829篇
  2007年   158555篇
  2006年   164895篇
  2005年   159027篇
  2004年   158308篇
  2003年   147103篇
  2002年   136545篇
  2001年   204616篇
  2000年   202567篇
  1999年   181385篇
  1998年   77902篇
  1997年   72186篇
  1996年   69840篇
  1995年   65614篇
  1994年   59526篇
  1993年   55048篇
  1992年   135287篇
  1991年   130096篇
  1990年   124575篇
  1989年   121289篇
  1988年   112226篇
  1987年   110124篇
  1986年   104436篇
  1985年   101508篇
  1984年   82381篇
  1983年   72448篇
  1982年   53598篇
  1981年   49566篇
  1980年   46411篇
  1979年   73273篇
  1978年   56685篇
  1977年   49922篇
  1976年   46375篇
  1975年   46795篇
  1974年   53952篇
  1973年   51797篇
  1972年   48589篇
  1971年   44720篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
111.
112.
BACKGROUND Approximately 20% of patients with neuroendocrine tumours(NETs) develop carcinoid syndrome(CS),characterised by flushing and diarrhoea.Somatostatin analogues or telotristat can be used to control symptoms of CS through inhibition of serotonin secretion.Although CS is often the cause of diarrhoea among patients with gastroenteropancreatic NETs(GEP-NETs),other causes to consider include pancreatic enzyme insufficiency(PEI),bile acid malabsorption and small intestinal bacterial overgrowth.If other causes of diarrhoea unrelated to serotonin secretion are mistaken for CS diarrhoea,these treatments may be ineffective against the diarrhoea,risking detrimental effects to patient quality of life.AIM To identify and synthesise qualitative and quantitative evidence relating to the differential diagnosis of diarrhoea in patients with GEP-NETs.METHODS Electronic databases(MEDLINE,Embase and the Cochrane Library) were searched from inception to September 12,2018 using terms for NETs and diarrhoea.Congresses,systematic literature review bibliographies and included articles were also hand-searched.Any study designs and publication types were eligible for inclusion if relevant data on a cause(s) of diarrhoea in patients with GEP-NETs were reported.Studies were screened by two independent reviewers at abstract and full-text stages.Framework synthesis was adapted to synthesise quantitative and qualitative data.The definition of qualitative data was expanded to include all textual data in any section of relevant publications.RESULTS Forty-seven publications(44 studies) were included,comprising a variety of publication types,including observational studies,reviews,guidelines,case reports,interventional studies,and opinion pieces.Most reported on PEI on/after treatment with somatostatin analogs;9.5%-84% of patients with GEP-NETs had experienced steatorrhoea or confirmed PEI.Where reported,14.3%–50.7% of patients received pancreatic enzyme replacement therapy.Other causes of diarrhoea reported in patients with GEP-NETs included bile acid malabsorption(80%),small intestinal bacterial overgrowth(23.6%-62%),colitis(20%) and infection(7.1%).Diagnostic approaches included faecal elastase,breath tests,tauroselcholic(selenium-75) acid(Se HCAT) scan and stool culture,although evidence on the effectiveness or diagnostic accuracy of these approaches was limited.Assessment of patient history or diarrhoea characteristics was also reported as initial approaches for investigation.From the identified evidence,if diarrhoea is assumed to be CS diarrhoea,consequences include uncontrolled diarrhoea,malnutrition,and perceived ineffectiveness of CS treatment.Approaches for facilitating differential diagnosis of diarrhoea include improving patient and clinician awareness of non-CS causes and involvement of a multidisciplinary clinical team,including gastroenterologists.CONCLUSION Diarrhoea in GEP-NETs can be multifactorial with misdiagnosis leading to delayed patient recovery and inefficient resource use.This systematic literature review highlights gaps for further research on prevalence of non-CS diarrhoea and suitability of diagnostic approaches,to determine an effective algorithm for differential diagnosis of GEP-NET diarrhoea.  相似文献   
113.
Background: Lay belief systems about the malleability of human attributes have been shown to impact behavior change in multiple domains. Addiction mindset—i.e., beliefs about the permanence (vs. malleability) of addiction — may affect cigarette smokers’ ability to quit, but this has never been examined. Objectives: The aims of the present research were to develop a measure of addiction mindset (study 1) and examine its associations with various psychological aspects of quitting smoking (study 2). Methods: In Study 1, using factor analysis of current smokers’ and nonsmokers’ (n?=?600) responses to 22 items designed to measure addiction mindset, we developed a reliable six-item Addiction Mindset Scale (AMS). In Study 2, adult smokers (n?=?200) completed the AMS, and measures of a number of psychological processes related to smoking. Results: Higher scores on the AMS, indicative of the belief that addiction is malleable (referred to as a growth mindset), were positively and significantly associated with greater motivation to quit, greater commitment to quitting, greater self-efficacy to abstain, less attribution of failure to lack of ability to change addiction, and fewer self-reported barriers to cessation (all p’s < .05). Conclusions: The results of this study show a relationship between the beliefs about the permanence of addiction and psychological processes relevant to quitting smoking. The findings underscore the potential of future research exploring how addiction mindsets relate to successful smoking cessation as well as other types of addictive behavior and how they can be applied to change people’s behavior.  相似文献   
114.
Pharmaceutical Chemistry Journal - An HPLC-MS method for simultaneous quantitative determination of a novel gestagenic pharmaceutical and two of its metabolites in rat and rabbit blood sera was...  相似文献   
115.
116.
117.
To determine percent of patients without malignancy and ≤ 40 years of age with high cumulative radiation doses through recurrent CT exams and assess imaging appropriateness. From the cohort of patients who received cumulative effective dose (CED) of ≥ 100 mSv over a 5-year period, a sub-set was identified with non-malignant disease. The top 50 clinical indications leading to multiple CTs were determined. Clinical decision support (CDS) system scores were analyzed using a widely adopted standard of 1–3 (red) as “not usually appropriate,” 4–6 (yellow) “may or may not be appropriate,” and 7–9 (green) “usually appropriate.” Clinicians reviewed patient records to assess compliance with appropriate use criteria (AUC). 9.6% of patients in our series were with non-malignant conditions and 1.4% with age ≤ 40 years. CDS scores (rounded) were 2% red, 38% yellow, 27% green, and 33% unscored CTs. Clinical society guidelines for CT exams, wherever available, were followed in 87.5 to 100% of cases. AUCs were not available for several clinical indications as also referral guidelines for serial CT imaging. More than half of CT exams were unrelated to follow-up of a primary chronic disease. We are faced with a situation wherein patients in age ≤ 40 years require or are thought to require many CT exams over the course of a few years but the radiation risk creates concern. There is a fair number of conditions for which AUC are not available. Suggested solutions include development of CT scanners with lesser radiation dose and further development of appropriateness criteria.  相似文献   
118.
Gattermann  J. 《Der Onkologe》2020,26(11):1010-1018
Die Onkologie - Die Corona-Pandemie hat in den letzten Monaten verdeutlicht, dass das Thema Sterblichkeit trotz erheblicher Fortschritte im Bereich der Hospiz- und Palliativversorgung zu...  相似文献   
119.
120.
Bulletin of Experimental Biology and Medicine - Ammonium, an end-product of catabolism, in low doses can promote adaptation of metabolic pathways in erythrocytes under conditions of extreme...  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