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   4107098篇
  免费   304699篇
  国内免费   10270篇
耳鼻咽喉   58036篇
儿科学   131342篇
妇产科学   111907篇
基础医学   573775篇
口腔科学   117912篇
临床医学   379095篇
内科学   796246篇
皮肤病学   91745篇
神经病学   341545篇
特种医学   159925篇
外国民族医学   1453篇
外科学   614056篇
综合类   91460篇
现状与发展   6篇
一般理论   1756篇
预防医学   328638篇
眼科学   95333篇
药学   303712篇
  90篇
中国医学   8066篇
肿瘤学   215969篇
  2018年   44390篇
  2017年   34094篇
  2016年   38783篇
  2015年   43815篇
  2014年   61545篇
  2013年   93464篇
  2012年   124238篇
  2011年   131741篇
  2010年   79105篇
  2009年   75549篇
  2008年   123541篇
  2007年   131178篇
  2006年   132921篇
  2005年   128472篇
  2004年   123770篇
  2003年   119187篇
  2002年   115971篇
  2001年   187616篇
  2000年   193136篇
  1999年   163913篇
  1998年   48942篇
  1997年   43577篇
  1996年   43172篇
  1995年   41881篇
  1994年   38841篇
  1993年   36355篇
  1992年   130101篇
  1991年   125893篇
  1990年   121692篇
  1989年   117608篇
  1988年   108677篇
  1987年   107035篇
  1986年   101095篇
  1985年   96852篇
  1984年   72827篇
  1983年   62237篇
  1982年   37503篇
  1981年   33765篇
  1979年   66947篇
  1978年   47374篇
  1977年   40151篇
  1976年   37604篇
  1975年   39722篇
  1974年   48167篇
  1973年   45955篇
  1972年   43233篇
  1971年   40046篇
  1970年   37444篇
  1969年   35379篇
  1968年   32531篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Abstract

Live discussions on the social media site Twitter or Twitter chats are gaining popularity as powerful tools for engaging a broad audience in an interactive discussion. Medical education, in particular, is experiencing an increase in the use of this modality to support informal learning, as a means to encourage collaboration and share best practices, and as a platform for large-scale mentorship. Despite this growth in popularity, there are limited data to guide medical educators on the fundamentals of organizing a Twitter chat. In this Twelve Tips article, we discuss strategies relevant to potential Twitter chat organizers. We have arranged the tips chronologically, beginning with a discussion of initial considerations when planning and formulating a chat topic and publicizing the chat to potentially interested people and groups, followed by practical considerations while hosting the chat, and finally strategies for evaluating and extending a Twitter chat’s impact.  相似文献   
92.
Abstract

Background: Substance use disorder (SUD) treatment centers serve a population of clients who have diverse needs, and may desire or require access to varied treatments while seeking care for their SUDs. While pharmacotherapies have increased in popularity for the treatment of SUDs, adoption rates do remain quite low. But a wider array of pharmacotherapies has become available in recent years which may shift the trend. This article helps shed light on how variations in SUD treatment centers develop and persist with regard to the adoption and delivery of off-label medications. Methods: We use a nationally representative and longitudinal sample of SUD treatment centers in the US (N?=?196). We use a logistic regression to analyze the relationship between organizational characteristics and offering any medications, off-label. We also use a negative binomial regression to analyze the relationship between organizational characteristics and the number of medications that were used off-label. Results: Our findings reveal that older centers, accredited centers, and centers that offer mental health screenings are all positively associated with the provision of off-label medication in SUD treatment. We also find a positive relationship between private funding and offering a greater number of off-label medications. Conclusions: Our results suggest that SUD clients who seek treatment from centers that offer medications off-label, may have access to a greater number of medication-assisted treatment options.  相似文献   
93.
ABSTRACT

We narrate our personal journey through the political minefield that is postpartum crisis by examining our communicative strategies across friendship, research partnership and as mothers on social media platforms. In a country with the highest postpartum maternal death rate in the industrialized world, we argue sharing narratives is a radical feminist act and one that must continue to draw attention to marginalized bodies. We hope to elevate the study of communication challenges mothers may experience for personal and political reasons.  相似文献   
94.
ABSTRACT

Background

Reactive balance training (RBT) has been previously found to reduce fall risk in individuals with sub-acute stroke; however, our understanding of the effects of RBT on specific balance impairments is lacking.  相似文献   
95.
Abstract

Artificial intelligence is a growing phenomenon that is driving major changes to how we deliver healthcare. One of its most significant and challenging contributions is likely to be in diagnosis. Artificial intelligence is challenging the physician’s exclusive role in diagnosis and in some areas, its diagnostic accuracy exceeds that of humans. We argue that we urgently need to consider how we will incorporate AI into our teaching of clinical reasoning in the undergraduate curriculum; students need to successfully navigate the benefits and potential issues of new and developing approaches to AI in clinical diagnosis. We offer a pedagogical framework for this challenging change to our curriculum.  相似文献   
96.
  • Over 21 years, 26 coronary artery fistulae were treated percutaneously, and 21 (81%) were successful.
  • There is still much to be learned about the physiology of coronary fistulae.
  • Transcatheter methods have improved over the years and permit a high success rate, but some cases still require a surgical approach.
  相似文献   
97.

Background

Spontaneous decolonization of antibiotic-resistant bacteria (ARB) takes time: approximately 25% after 30 days for carbapenem-producing Enterobacteriaceae or extended-spectrum beta-lactamase-producing Enterobacteriaceae. Faecal microbiota transplantation (FMT) has been proposed as a new strategy to promote decolonization in order to reduce the risk of superinfection due to these ARB. This paper discusses the literature on the use of FMT for this indication, and the improvement levers available to promote its efficacy.

Methods

Literature available to date concerning the use of FMT to eradicate ARB was reviewed, and the different factors that may have influenced the efficacy of decolonization were evaluated.

Results

Four axes that could have played major roles in the efficacy of FMT were identified: bowel preparation before FMT; donor; dose; and thermal conditioning of faeces. The positive or negative impact of each on the outcome of FMT is discussed.

Conclusion

Although FMT is very efficient for the eradication of Clostridium difficile, the same ‘recipe’ cannot be used for the eradication of ARB. Working together with expert centres may help to improve the efficacy of FMT for this indication, and enable the reduction of in-hospital isolation precautions.  相似文献   
98.

Objectives

Triazole resistance in Aspergillus spp. is emerging and complicates prophylaxis and treatment of invasive aspergillosis (IA) worldwide. New polymerase chain reaction (PCR) tests on broncho-alveolar lavage (BAL) fluid allow for detection of triazole resistance at a genetic level, which has opened up new possibilities for targeted therapy. In the absence of clinical trials, a modelling study delivers estimates of the added value of resistance detection with PCR, and which empiric therapy would be optimal when local resistance rates are known.

Design

A decision-analytic modelling study was performed based on epidemiological data of IA, extended with estimated dynamics of resistance rates and treatment effectiveness. Six clinical strategies were compared that differ in use of PCR diagnostics (used vs not used) and in empiric therapeutic choice in case of unknown triazole susceptibility: voriconazole, liposomal amphotericin B (LAmB) or both. Outcome measures were proportion of correct treatment, survival and serious adverse events.

Results

Implementing aspergillus PCR tests was projected to result in residual treatment-susceptibility mismatches of <5% for a triazole resistance rate up to 20% (using voriconazole). Empiric LAmB outperformed voriconazole at resistance rates >5–20%, depending on PCR use and estimated survival benefits of voriconazole over LAmB. Combination therapy of voriconazole and LAmB performed best at all resistance rates, but the advantage over the other strategies should be weighed against the expected increased number of drug-related serious adverse events. The advantage of combination therapy over LAmB monotherapy became smaller at higher triazole resistance rates.

Conclusions

Introduction of current aspergillus PCR tests on BAL fluid is an effective way to increase the proportion of patients that receive targeted therapy for IA. The results indicate that close monitoring of background resistance rates and adverse drug events are important to attain the potential benefits of LAmB. The choice of strategy ultimately depends on the probability of triazole resistance, the availability of PCR and individual patient characteristics.  相似文献   
99.
ABSTRACT

Bellicose metaphors for cancer are ubiquitous. But are they good metaphors for health communicators to use? Because metaphors can guide reasoning about abstract concepts, framing cancer with metaphors of battle, war, and enemies leads people to apply attributes of these concepts to cancer. The current research investigates how this affects inferences about cancer treatment, prevention, and monitoring. Battles and war are usually seen as being difficult. Indeed, reading about a person’s “battle” or “fight” against cancer makes cancer treatment seem more difficult (studies 1–4). One way to approach a battle is to surrender and give up control. Consistent with this implication, battle metaphors increase fatalistic beliefs about cancer prevention (e.g. believing that there is little one can do to prevent getting cancer; study 3). Finally, even though battles invoke vigilance and action, Study 4 failed to find that such metaphors motivate people to immediately see their doctor when imagining a cancer scare. These findings suggest that bellicose metaphors for cancer can influence the health beliefs of nonpatients in ways that may make them less willing to enact healthy behaviors  相似文献   
100.
Purpose

Prolonged mechanical ventilation (MV) is a major complication following cardiac surgery. We conducted a secondary analysis of the Transfusion Requirements in Cardiac Surgery (TRICTS) III trial to describe MV duration, identify factors associated with prolonged MV, and examine associations of prolonged MV with mortality and complications.

Methods

Four thousand, eight hundred and nine participants undergoing cardiac surgery at 71 hospitals worldwide were included. Prolonged MV was defined based on the Society of Thoracic Surgeons definition as MV lasting 24 hr or longer. Adjusted associations of patient and surgical factors with prolonged MV were examined using multivariable logistic regression. Associations of prolonged MV with complications were assessed using odds ratios, and adjusted associations between prolonged MV and mortality were evaluated using multinomial regression. Associations of shorter durations of MV with survival and complications were explored.

Results

Prolonged MV occurred in 15% (725/4,809) of participants. Prolonged MV was associated with surgical factors indicative of complexity, such as previous cardiac surgery, cardiopulmonary bypass duration, and separation attempts; and patient factors such as critical preoperative state, left ventricular impairment, renal failure, and pulmonary hypertension. Prolonged MV was associated with perioperative but not long-term complications. After risk adjustment, prolonged MV was associated with perioperative mortality; its association with long-term mortality among survivors was weaker. Shorter durations of MV were not associated with increased risk of mortality or complications.

Conclusion

In this substudy of the TRICS III trial, prolonged MV was common after cardiac surgery and was associated with patient and surgical risk factors. Although prolonged MV showed strong associations with perioperative complications and mortality, it was not associated with long-term complications and had weaker association with long-term mortality among survivors.

Study registration

www.ClinicalTrials.gov (NCT02042898); registered 23 January 2014. This is a substudy of the Transfusion Requirements in Cardiac Surgery (TRICS) III trial.

  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