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   2975篇
  免费   173篇
  国内免费   17篇
耳鼻咽喉   26篇
儿科学   75篇
妇产科学   77篇
基础医学   427篇
口腔科学   106篇
临床医学   289篇
内科学   648篇
皮肤病学   45篇
神经病学   287篇
特种医学   45篇
外科学   339篇
综合类   18篇
一般理论   6篇
预防医学   261篇
眼科学   57篇
药学   211篇
中国医学   12篇
肿瘤学   236篇
  2023年   24篇
  2022年   35篇
  2021年   59篇
  2020年   30篇
  2019年   48篇
  2018年   72篇
  2017年   46篇
  2016年   74篇
  2015年   65篇
  2014年   94篇
  2013年   154篇
  2012年   213篇
  2011年   204篇
  2010年   117篇
  2009年   101篇
  2008年   163篇
  2007年   195篇
  2006年   162篇
  2005年   182篇
  2004年   136篇
  2003年   153篇
  2002年   141篇
  2001年   59篇
  2000年   37篇
  1999年   61篇
  1998年   34篇
  1997年   20篇
  1996年   25篇
  1995年   26篇
  1994年   15篇
  1993年   18篇
  1992年   30篇
  1991年   32篇
  1990年   38篇
  1989年   32篇
  1988年   18篇
  1987年   19篇
  1986年   21篇
  1985年   16篇
  1984年   16篇
  1983年   13篇
  1981年   14篇
  1980年   13篇
  1979年   12篇
  1974年   9篇
  1973年   13篇
  1972年   9篇
  1971年   8篇
  1969年   8篇
  1967年   7篇
排序方式: 共有3165条查询结果,搜索用时 15 毫秒
41.
42.
Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) is a zoonotic pathogen for persons in contact with horses. In horses, S. zooepidemicus is an opportunistic pathogen, but human infections associated with S. zooepidemicus are often severe. Within 6 months in 2011, 3 unrelated cases of severe, disseminated S. zooepidemicus infection occurred in men working with horses in eastern Finland. To clarify the pathogen’s epidemiology, we describe the clinical features of the infection in 3 patients and compare the S. zooepidemicus isolates from the human cases with S. zooepidemicus isolates from horses. The isolates were analyzed by using pulsed-field gel electrophoresis, multilocus sequence typing, and sequencing of the szP gene. Molecular typing methods showed that human and equine isolates were identical or closely related. These results emphasize that S. zooepidemicus transmitted from horses can lead to severe infections in humans. As leisure and professional equine sports continue to grow, this infection should be recognized as an emerging zoonosis.  相似文献   
43.
A group of clinicians, teachers and researchers in the University of Oulu have been worried for years about the predominantly biomedical orientation in the local Faculty of Medicine. Therefore, a project group was founded in 1992 to develop the medical degree programme towards a more comprehensive model. This article introduces the main strategies used in the process of change and describes the challenges encountered during the process. There are still many problems in the education of medical students towards a patient and family orientation and in the effort to change the whole medical culture of the university from a biomedical to a biopsychosocial approach. However, in the postgraduate education of general practitioners, we no longer prefer to teach only doctors, but education on the biopsychosocial model will also be arranged to the interdisciplinary teams working in the municipalities in the Province of Oulu in Finland.  相似文献   
44.
Objectives: Most studies of orthostatic hypotension (OH) have focused on community-dwelling and institutionalized patient populations. Less is known about OH in hospitalized patients. Moreover, a comprehensive review of OH in internal medicine wards has not been published in the English literature. Our purpose is to provide current information regarding OH in internal medicine inpatients.

Methods: A comprehensive search of medical databases was performed for potentially relevant articles, using the following keywords: postural or orthostatic hypotension, with the combination of hospitalization or internal medicine. Inclusion criteria were: population of patients hospitalized for acute disorders in internal medicine or geriatric wards with a sample size of ≥50 and publication as an original full-length article in the English language. Data from 14 selected studies are reviewed, including: pathophysiology, evaluation, prevalence, manifestations, risk factors, prognosis, and management.

Results: OH is a common and often symptomatic disorder in elderly internal medicine patients. The prevalence of OH in this population ranges from 22–75%. There are substantial discrepancies between the studies reviewed regarding definitions and means of evaluating OH. OH in internal medicine wards is largely non-neurogenic and multifactorial. The main predisposing factors for OH are prolonged bed rest, hypertension, and heart failure. OH in internal medicine wards is managed mainly with non-pharmacologic interventions, and is frequently reversible.

Conclusions: In internal medicine inpatients, OH warrants attention because this disorder is common, potentially dangerous, and treatable. In the hospital setting, OH should be routinely assessed on ambulation, following the current guidelines for OH definition and meaning.  相似文献   

45.
46.
Introduction: In the past eight years, the European Association of Poisons Centres and Clinical Toxicologists (EAPCCT) has been intensively involved in a European Commission led process to develop EU legislation on the information of hazardous products that companies have to notify to EU Poisons Centres (or equivalent “appointed bodies”). As a result of this process, the Commission adopted Regulation (EU) No 2017/542, amending the CLP Regulation by adding an Annex on harmonised product submission requirements.

Harmonised mixture information requirements: Detailed and consistent information on the composition of the hazardous product will become available to EU Poisons Centres (PC). The information will be submitted by companies to PCs (or equivalent “appointed bodies”) using a web-based software application or in-house software. Two new important features are introduced. Firstly, to be able to rapidly identify the product formula, a Unique Formula Identifier (UFI) on the product label links to the submitted information. Secondly, for better comparability of reports on poisonings between EU member states, a harmonised Product Categorisation System will specify the intended use of a product. Rapid product identification and availability of detailed composition information will lead to timely and adequate medical intervention. This may lead to considerable reduction in healthcare costs.

Additionally, for companies trading across the EU, costs of submission of this information will be reduced significantly.

Next steps: From 2017, an implementation period has started, consisting of a three-year period for stakeholders to implement the new requirements, followed by a gradual applicability for consumer products (2020), professional products (2021) and industrial use-only products (2024). Technical tools to generate the electronic format and the UFI together with guidance documents are expected to be made available by the end of 2017 by the European Chemicals Agency (ECHA). Guidance on interpretation of legal text and ECHA helpdesk support are planned to be ready at the end of 2018.  相似文献   

47.
48.
49.
An ultrasound-guided double pass biopsy technique using a large bore cutting needle via an anterior subcostal route (USAB) is described. The diagnostic adequacy of this biopsy procedure was evaluated in comparison with the traditional Menghini technique in 200 cases of suspected chronic liver disease randomly assigned to the two different procedures. Retrieval rate was better in the USAB group. The sample length was less than 15 mm in four cases in the USAB group and in 19 cases in the Menghini group. In three cases in the USAB group the second pass modified the diagnosis of the first specimen from chronic active hepatitis to active cirrhosis. In order to evaluate the safety and discomfort of the two procedures 340 patients assigned to the different techniques had liver ultrasound scans 6 and 24 h following percutaneous biopsy. USAB was associated with a reduced frequency of complications (one out of 170 patients vs. seven out of 170 patients who had the intercostal Menghini procedure). In our study, USAB seems to offer better sampling and size of individual samples, together with reduced frequency of major and minor complications.  相似文献   
50.
AIMS: The aims of the present study were: (a) to demonstrate whether quantitative myocardial contrast echocardiography can detect the increase in coronary flow induced by dipyridamole infusion vasodilation through the myocardial opacification due to the transit of microbubbles, both at rest and after dipyridamole induced vasodilation; (b) to explore the coronary microcirculatory function before and after dipyridamole in two different models: asymptomatic and relatively young hypertensive patients with a mild degree of left ventricular hypertrophy, and healthy controls. METHODS AND RESULTS: Two groups of strictly age-matched males were studied (case-control study): 10, relatively young and asymptomatic essential hypertensive patients with a mild degree of left ventricular hypertrophy with a normal left ventricular function, and 10 healthy controls. The main findings were: the microbubbles' appearance area was significantly lower in hypertensive patients than in controls (P<0.05) because of a significantly lower time to peak. The peak intensity at rest was higher in hypertensives than in controls (P<0.05); but the per cent increase after vasodilatory stimulus was significantly higher in controls (+71% in controls vs +31% in hypertensives; P<0.05). The microbubbles' disappearance area was comparable in both groups at rest; the per cent increase of this parameter after dipyridamole was significantly higher in controls (+124%) than in hypertensives (+90%) (P<0.05). The results achieved in this study documented that the coronary microcirculation in hypertensive patients presenting a mild degree of left ventricular hypertrophy, explored with quantitative myocardial contrast echocardiography, showed a different behaviour in comparison with controls, in the vasodilatory response to dipyridamole. CONCLUSION: The coronary microcirculation in hypertensives showed a reduced vasodilation capacity of the resistance arterioles under dipyridamole induced vasodilatation, and a possible impairment of the endothelium dependent vasodilation. This happened despite an increase in the left ventricular mass, where the relation between capillary bed distribution and hypertrophied myocardium (rarefaction phenomenon) is not completely respected.  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