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   3934篇
  免费   217篇
  国内免费   19篇
耳鼻咽喉   27篇
儿科学   156篇
妇产科学   147篇
基础医学   407篇
口腔科学   246篇
临床医学   289篇
内科学   823篇
皮肤病学   72篇
神经病学   198篇
特种医学   204篇
外科学   436篇
综合类   144篇
预防医学   319篇
眼科学   52篇
药学   228篇
  1篇
中国医学   90篇
肿瘤学   331篇
  2023年   21篇
  2022年   43篇
  2021年   76篇
  2020年   52篇
  2019年   63篇
  2018年   87篇
  2017年   66篇
  2016年   76篇
  2015年   102篇
  2014年   135篇
  2013年   161篇
  2012年   213篇
  2011年   221篇
  2010年   149篇
  2009年   134篇
  2008年   166篇
  2007年   177篇
  2006年   172篇
  2005年   135篇
  2004年   102篇
  2003年   102篇
  2002年   109篇
  2001年   91篇
  2000年   55篇
  1999年   71篇
  1998年   53篇
  1997年   68篇
  1996年   50篇
  1995年   53篇
  1994年   67篇
  1993年   46篇
  1992年   43篇
  1991年   51篇
  1990年   49篇
  1989年   41篇
  1988年   43篇
  1987年   40篇
  1986年   36篇
  1985年   33篇
  1984年   31篇
  1983年   25篇
  1982年   18篇
  1981年   28篇
  1980年   22篇
  1959年   35篇
  1958年   58篇
  1957年   87篇
  1956年   45篇
  1955年   75篇
  1954年   68篇
排序方式: 共有4170条查询结果,搜索用时 0 毫秒
1.

Objective

The aim of this paper is to study the opportunity costs (OC) that are involved in being a caregiver and to compare them with the direct costs assumed by the State and the families. We evaluate direct cost (those that imply a payment-out-of-pocket) and indirect cost (those that imply a dedication in time). We hypothesized that costs increase with the severity of the dementia, with the educational level and active occupational situation of caregiver. They are greater if the caregiver is male, but if the patient and caregiver cohabit they are reduced.

Method

778 surveys were analyzed. Data was collected using a questionnaire specifically designed for the purpose, with the collaboration of Alzheimer's Diseases Associations in Andalusia (Spain). For the indirect cost, we used the reveal preferences method. For the comparison between groups an ANOVA and a MANOVA was done.

Results

The hypotheses were confirmed. The OC exponentially increases with severity. More than 55% of costs are assumed by families. Occupied people have higher educational level and incomes and contract more external support. Costs are significantly higher for male caregivers. Cohabiting reduces all kinds of costs.

Conclusions

The relationship between educational level and employment situation lead to think that if these variables are greater more people will seek professional support. Cultural reasons still maintain women as main caregivers for all educational levels. The existence of these informal caregivers as the main care providers is a saving for the State, and a brake for the development of professional supply.  相似文献   
2.
3.
BACKGROUND: Graft-vs.-host disease (GVHD) is the major cause of morbidity and mortality in patients undergoing allogeneic Bone Marrow Transplantation (BMT). The aim of our study was to identify the most relevant histological features for diagnosis of chronic Graft-vs.-Host Disease (cGVHD) in oral mucosa and minor salivary glands of 25 patients, as well as to evaluate the immunophenotype of the inflammatory cells. METHODS: Sixteen patients that were submitted to allogeneic BMT but did not present cGVHD were selected as a control group. The sections were studied on H & E and CD68, CD45, CD4, CD8, CD20 staining. RESULTS: The most frequent histologic findings in oral mucosa at the day of diagnosis of cGVHD were: hydropic degeneration of the basal layer of the epithelium, apoptotic bodies, lymphocytic infiltration, and focal or total cleavage between the epithelial and connective tissue. In the labial salivary glands (LSG), lymphocytic infiltration, acinar loss and fibrosis were the main alterations. Cytotoxic CD8-T cells and macrophages were predominant both in the epithelium and connective tissue, as well as in minor salivary glands. CONCLUSIONS: Histological features were useful in the diagnosis of oral cGVHD. It is suggested that CD8-T cells and macrophages play important role in the pathogenesis of the disease.  相似文献   
4.
Abstract: This paper dicusses the use of esophageal dilatation with a Rigiflex TTS balloon. This method was used 45 times on 11 patients affected by anastomotic or a severe grade peptic esophageal stenosis. Fluoroscopic guidance was used in 36 procedures (80%) without effecting the mean duration of the treatment (12 minutes). The results were considered satisfactory when these goals had been achieved: a) dilatation of the stenosis over 15 mm; b) a dysphagia free-time of more than 6 months. A satisfactory result was achieved in 10 patients (90.9%), without deaths and major complications. 5 patients received 1 dilatation and the other 5 needed, 3-3-4-7–11 procedures respectively to obtain a satisfactory result. On these basis we consider that its great efficacy, security and tolerability depend on the following characteristics of the Rigiflex TTS balloon: 1) “radial” dilatation; 2) the possibility of introducing the balloon through the operative channel of the fiberscope; 3) direct visualization of the stenosis during dilatation. The following disadvantages with this method are: the absence of a tactile sensation of dilatation and the elevated cost of the instrument. We conclude that the Rigiflex TTS balloon is an important alternative to guide-wire techniques, especially for the treatment of severe esophageal strictures.  相似文献   
5.
Diet and chronic atrophic gastritis: a case-control study   总被引:2,自引:0,他引:2  
A hospital-based case-control study of gastric cancer precursor lesions was conducted in a high-risk black population in southern Louisiana. Ninety-three subjects with biopsy-proved advanced chronic atrophic gastritis were compared to two control series: a gastroscopy clinic series and a general hospital-admission series. Dietary case-control differences indicated a protective effect associated with fruit and vegetable intake and with dietary vitamin C and a risk elevation associated with milk consumption. The protective effect associated with consumption of fruits, vegetables, and vitamin C is consistent with findings for gastric cancer and with the etiologic hypothesis of intragastric nitrosation. A twofold increased risk was associated with cigarette smoking. Gastric juice pH, NO3-, and NO2- were determined for subjects undergoing gastroscopy, and comparisons were made between this high-risk U.S. group and a Colombian population with a much greater magnitude of risk; the latter had higher NO3- and NO2- levels. An increase in pH was associated with increasing severity of gastric lesions. Levels of pH and NO2- concentration were significantly correlated (P less than .0005); however, in Louisiana the large difference in NO2- concentration associated with pH elevation is not associated with histopathologic severity. Divergent trends with severity of lesions for NO3- concentration were seen in the two populations.  相似文献   
6.
7.
Early gastric cancer. 21-year experience.   总被引:7,自引:1,他引:6       下载免费PDF全文
W L Bringaze  rd  C W Chappuis  P Correa    I Cohn  Jr 《Annals of surgery》1986,204(2):103-107
From 1963 through 1983, 327 patients underwent resection for gastric adenocarcinoma at Charity Hospital in New Orleans. Fifteen lesions (4.6%) were early gastric carcinoma (limited to the mucosa or submucosa regardless of nodal metastases). These lesions were in eight men and seven women (14 blacks and 1 white), with a mean age of 65.3 years (range: 52-80 years). Upper gastrointestinal series were obtained in 13 (6 suspicious, 2 inconclusive, and 5 normal). By comparison, endoscopy on 11 patients provided a tissue diagnosis in ten patients (90.9%). Surgical procedures ranged from total gastrectomy to a local excision, and every specimen was free of lymph node metastases. Macroscopically, there were six Type I, four Type IIb, and Type IIc, three Type III, and one with two separate lesions (IIa and IIb); microscopically, ten were intramucosal and five had submucosal invasion. Five-year survival calculated by the actuarial method was 64.2% (observed) and 100% (adjusted). This compares with 18.8% (observed) for all 327 patients. Six of the patients with early gastric cancer are alive (range: 16-219 months). The nine patients who died had no evidence of recurrent disease at the time of death. Surgical resection of early gastric carcinoma in the United States offers an excellent prognosis similar to the Japanese experience. Increased detection of gastric carcinoma in its curable stages may be achieved through early endoscopic investigation of symptomatic patients.  相似文献   
8.
Anulus fibrosus in bulging intervertebral disks   总被引:1,自引:0,他引:1  
Yu  SW; Haughton  VM; Sether  LA; Wagner  M 《Radiology》1988,169(3):761-763
In this investigation the association of radial tears of the anulus fibrosus and bulging of the intervertebral disk was studied. An index of disk bulging was measured in sagittal anatomic sections in 149 lumbar disks from 31 cadavers. The indexes of disk bulging were correlated with stages of disk development and the presence of an annular tear. The largest disk-bulging indexes were always associated with radial tears of the anulus. Eighty-four percent of the disks with radial tears had disk-bulging indexes greater than 2.5 mm. Most normal adult disks had an index of less than 2.5 mm. The results challenge the concept that the anulus fibrosus is intact in bulging disks, although ruptured in herniated disks.  相似文献   
9.
The relative strengths of the etiologic factors identified for gastric cancer are discussed. On the basis of available scientific data, it is recommended that dietary prevention of gastric cancer be based on attempts to reduce the ingestion of foods with a high content of salt and to increase the intake of fresh fruits and vegetables. Other identified etiologic factors offer promise and are being investigated but do not yet justify recommendation to the general public.  相似文献   
10.
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