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   10801篇
  免费   734篇
  国内免费   64篇
耳鼻咽喉   62篇
儿科学   247篇
妇产科学   281篇
基础医学   1538篇
口腔科学   396篇
临床医学   991篇
内科学   2214篇
皮肤病学   195篇
神经病学   1326篇
特种医学   321篇
外科学   1252篇
综合类   25篇
现状与发展   1篇
一般理论   8篇
预防医学   967篇
眼科学   121篇
药学   711篇
中国医学   49篇
肿瘤学   894篇
  2024年   11篇
  2023年   115篇
  2022年   198篇
  2021年   424篇
  2020年   257篇
  2019年   393篇
  2018年   429篇
  2017年   340篇
  2016年   394篇
  2015年   372篇
  2014年   465篇
  2013年   605篇
  2012年   874篇
  2011年   851篇
  2010年   455篇
  2009年   431篇
  2008年   679篇
  2007年   643篇
  2006年   634篇
  2005年   577篇
  2004年   541篇
  2003年   476篇
  2002年   386篇
  2001年   116篇
  2000年   86篇
  1999年   111篇
  1998年   59篇
  1997年   70篇
  1996年   39篇
  1995年   34篇
  1994年   31篇
  1993年   24篇
  1992年   56篇
  1991年   66篇
  1990年   35篇
  1989年   42篇
  1988年   36篇
  1987年   35篇
  1986年   27篇
  1985年   27篇
  1984年   25篇
  1983年   8篇
  1982年   15篇
  1981年   9篇
  1980年   8篇
  1979年   11篇
  1977年   11篇
  1974年   13篇
  1973年   10篇
  1971年   8篇
排序方式: 共有10000条查询结果,搜索用时 116 毫秒
961.

Background

Adrenal cavernous hemangiomas are very rare benign tumors that usually present as incidental findings on abdominal imaging. Preoperative differential diagnosis from other benign or malignant adrenal neoplasms may be challenging.

Case presentation

A 70-year old man was referred for an 8-cm abdominal mass incidentally discovered on a contrast-enhanced computed tomography (CT) performed to investigate a pulmonary nodule. Biochemical tests ruled out any endocrine dysfunction and iodine 123 metaiodobenzylguanidine whole body scintiscan single-photon emission CT excluded a pheocromocitoma. Findings on magnetic resonance imaging were non-specific and the patient was elected for a left adrenalectomy. Histopathological diagnosis revealed a cavernous hemangioma. A portion of the resected tissue was tested for drug sensitivity to mitotane, doxorubicin, and sunitinib.

Conclusions

Adrenal hemangioma is a rare disease but should be included in the differential diagnosis of adrenal tumors. The surgical resection is generally required to exclude malignant disease, resolve pressure-related symptoms, and prevent retroperitoneal hemorrhage. Although specific features in diagnostic imaging are often lacking, if the diagnosis is established preoperatively a laparoscopic adrenalectomy can be performed due to the benign nature of the lesion. Doxorubicin and sunitinib were both capable of reducing primary culture cell viability, this suggest that similar drugs may be useful in the medical treatment of adrenal hemangiomas.
  相似文献   
962.
Health status, functional status, and social influences were analyzed as risk factors associated with mortality in 1201 elderly subjects (70–75 years old), living in the center of Brescia, Northern Italy, followed up for three years.Mortality was positively associated with degree of impairment in health status, functional status, and mental status as measured by cognitive function and mood depression. Among social conditions no relation was found between mortality and living alone, education, or income, while a significant inverse relationship has been found between mortality and activities. In defining risk factors of mortality in aged people not only health status and cognitive function have to be taken into account but also social activities; these latter may act as protective factors buffering the organism from the effects of noxious stimuli.Paper originally presented at the XIVth International Congress of Gerontology, Acapulo, Mexico 18–23 June 1989.  相似文献   
963.
In hypertensive patients without prevalent cardiovascular disease, enhanced left atrial systolic force is associated with left ventricular hypertrophy and increased preload. It also predicts cardiovascular events in a population with high prevalence of obesity. Relations between left atrial systolic force and left ventricular geometry and function have not been investigated in high-risk hypertrophic hypertensive patients. Participants in the Losartan Intervention For Endpoint reduction in hypertension echocardiography substudy without prevalent cardiovascular disease or atrial fibrillation (n = 567) underwent standard Doppler echocardiography. Left atrial systolic force was obtained from the mitral orifice area and Doppler mitral peak A velocity. Patients were divided into groups with normal or increased left atrial systolic force (>14.33 kdyn). Left atrial systolic force was high in 297 patients (52.3%), who were older and had higher body mass index and heart rate (all P < 0.01) but similar systolic and diastolic blood pressure, in comparison with patients with normal left atrial systolic force. After controlling for confounders, increased left atrial systolic force was associated with larger left ventricular diameter and higher left ventricular mass index (both P < 0.01). Prevalence of left ventricular hypertrophy was greater (84 vs. 64%; P < 0.001). Participants with increased left atrial systolic force exhibited normal ejection fraction; higher stroke volume, cardiac output, transmitral peak E velocities and peak A velocities; and lower E/A ratio (all P < 0.01). Enhanced left atrial systolic force identifies hypertensive patients with greater left ventricular mass and prevalence of left ventricular hypertrophy, but normal left ventricular chamber systolic function with increased transmitral flow gradient occurring during early filling, consistent with increased preload.  相似文献   
964.
Objective: Several studies have examined the characteristics of anti‐smoking advertisements that are associated with quitting behaviour. Some studies use researchers or graduate students to code advertisement characteristics, while others recruit smokers or members of the general public. The aim of this study was to assist future campaign development by assessing whether anti‐smoking advertisement characteristics are coded differently by smokers and ‘experts’ (individuals with knowledge of health promotion, public health or advertising). Methods: A total of 49 smokers and 42 experts coded anti‐smoking advertisements according to four key characteristics (emotional/cognitive approach, negative/positive tone, message frame, and main message) and the use of eight executional techniques. Chi‐squared tests were used to measure differences in coding outcomes between smokers and experts. Results: There were significant differences between smokers and experts in the coding of all key characteristics and four of the eight executional techniques. Compared with smokers, experts were more likely to perceive advertisements as negative in tone and as inducing fear. Conclusions: Smokers and experts perceived the characteristics of anti‐smoking advertisements differently. Implications for public health: Differences between smokers and experts may need to be taken into account where studies use either of these groups to code advertisements for campaign development or evaluation purposes.  相似文献   
965.
The retrieval of a polystyrene macro-plastic piece stranded on the shores in King George Island (South Shetlands, Antarctica) gave the opportunity to explore the associated bacterial flora. A total of 27 bacterial isolates were identified by molecular 16s rRNA gene sequencing and 7 strains were selected and screened for their ability to produce biofilm and antibiotic susceptibility profiles. All the bacterial isolates were able to produce biofilm. The Kirby-Bauer disk diffusion susceptibility test to 34 antibiotics showed multiple antibiotic resistances against the molecules cefuroxime and cefazolin (belonging to cephalosporins), cinoxacin (belonging to quinolones) and ampicillin, amoxicillin + clavulanic acid, carbenicillin and mezlocillin (belonging to beta-lactams). The obtained results suggest that plastics can serve as vectors for the spread of multiple resistances to antibiotics across Antarctic marine environments and underline the relevance of future studies on this topic.  相似文献   
966.
967.
968.
Now you see/C it     
Bleeding disorders are common. In addition to thinking about disorders relating to abnormal platelets or clotting factors, clinicians should consider disorders of vascular integrity in their differential diagnosis. We present a patient with atypical, spontaneous bleeding that was due to scurvy, an often overlooked cause. Clinicians should be aware of the risk factors for the development of scurvy, such as poor dietary intake, male gender, smoking, alcohol abuse, as well as its classic manifestations, including gingival bleeding, spontaneous bruising, corkscrew hairs, and poor wound healing, A heightened awareness may lead to earlier diagnosis and treatment.  相似文献   
969.
We report 2 cases of exclusion of visceral artery aneurysms. The first was a common hepatic artery aneurysm treated with a multilayer stent; the second was a celiac trunk aneurysm excluded by a covered stent. Computed tomographic angiography was performed at regular intervals after each procedure, together with echo color Doppler imaging and contrast‐enhanced sonography. Computed tomographic angiography and contrast‐enhanced sonography were able to detect endoleaks in both patients and the related inflow vessel; moreover, diameter measurements of the sacs were identical. In our preliminary experience, contrast‐enhanced sonography appeared to be as accurate as computed tomographic angiography after endovascular visceral artery aneurysm exclusion.  相似文献   
970.
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