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   2441篇
  免费   171篇
  国内免费   6篇
耳鼻咽喉   35篇
儿科学   63篇
妇产科学   92篇
基础医学   343篇
口腔科学   99篇
临床医学   150篇
内科学   438篇
皮肤病学   63篇
神经病学   282篇
特种医学   83篇
外科学   305篇
综合类   2篇
一般理论   2篇
预防医学   196篇
眼科学   120篇
药学   170篇
中国医学   5篇
肿瘤学   170篇
  2023年   23篇
  2022年   19篇
  2021年   77篇
  2020年   28篇
  2019年   54篇
  2018年   97篇
  2017年   55篇
  2016年   78篇
  2015年   68篇
  2014年   93篇
  2013年   128篇
  2012年   183篇
  2011年   216篇
  2010年   102篇
  2009年   86篇
  2008年   170篇
  2007年   164篇
  2006年   174篇
  2005年   149篇
  2004年   118篇
  2003年   108篇
  2002年   108篇
  2001年   28篇
  2000年   25篇
  1999年   19篇
  1998年   13篇
  1997年   18篇
  1996年   10篇
  1995年   4篇
  1994年   4篇
  1992年   10篇
  1991年   11篇
  1990年   19篇
  1989年   7篇
  1988年   11篇
  1987年   5篇
  1986年   9篇
  1985年   12篇
  1983年   4篇
  1982年   4篇
  1979年   4篇
  1967年   4篇
  1935年   4篇
  1933年   8篇
  1932年   8篇
  1931年   5篇
  1930年   4篇
  1929年   4篇
  1928年   4篇
  1923年   5篇
排序方式: 共有2618条查询结果,搜索用时 343 毫秒
1.
2.
The Latin American population has a double way of immigration, one toward the United States by proximity and another toward Spain by sociocultural affinity. This population increase is affecting organ donation and transplantation in receiving countries.

Objective

To analyze the brain death (BD) concept knowledge in the Dominican Republic immigrant population in Florida (United States) and Spain.

Method

Population under study: Population born in the Dominican Republic, resident in Florida (United States) and in Spain. Inclusion criteria: Population older than 15 years stratified by age and sex. Assessment instrument: Donation attitude questionnaire PCID-DTO-Ríos. Fieldwork: Random selection based on stratification. Immigration support association collaboration in Florida and Spain was needed to locate potential respondents. Completion was anonymous and self-administered, with verbal consent.

Results

A total of 123 respondents, 57 residents in Spain and 66 in Florida, have been included in the study. The 27% (n = 33) of the respondents knowledgeable of the BD concept consider it the death of an individual. Of the remainder, 52% (n = 64) do not know about it, and the remaining 21% (n = 26) believe it does not mean the death of a patient. No differences were observed regarding migration countries (P > .05). There was no association of the BD concept with other psychosocial factors analyzed or with the attitude toward organ donation.

Conclusions

Knowledge of the BD concept among the Dominican immigrant population is similar in Spain and Florida, and, unlike most studies, there is no objective association with the attitude toward organ donation.  相似文献   
3.

Background  

Reports on childhood cancer survivors estimated cumulative probability of developing secondary neoplasms vary from 3,3% to 25% at 25 years from diagnosis, and the risk of developing another cancer to several times greater than in the general population.  相似文献   
4.
Although most congenital heart defects are isolated abnormalities of embryonic development, with little genetic contribution, a small number are components of syndromes. In such cases, an accurate diagnosis has important implications for individual prognosis and familial genetic counseling. Alagille syndrome (AGS) is a dominantly inherited multisystem developmental disorder, which primarily affects the liver, heart, eyes, skeleton, and face. In recent years, the identification of the AGS gene has drawn attention to the existence of subclinical carriers, and broadened the spectrum of phenotypical variation associated with this syndrome. The authors present a case of mother and son with benign stenosis of the pulmonary artery branches. Subtle facial aspects suggested the diagnosis of AGS, which was confirmed by molecular analysis. Relevant clinical investigations and diagnostic implications are discussed.  相似文献   
5.
The purpose of this study was to evaluate the ability of helical computed tomography (CT) to detect arterial injuries in gunshot wounds to the neck. In a blinded retrospective review, 54 helical CT scans of the cervical spine were evaluated for bullet/bone fragments, subcutaneous air, bullet path, hematoma, spine fractures, and pharyngoesophageal compromise. The distance of fragments to a major vessel was calculated. CT findings that correlated significantly with major arterial injury included the presence of fragments (bullet/bone) close to a major vessel (2.5 mm) and spine fractures. Visualizing fragments <5 mm from a vessel or a transcervical bullet trajectory predicted 12 of 13 major arterial injuries. We conclude that CT clearly depicts anatomic damage. Specific findings, such as the location of fragments and bullet trajectory adjacent to a vessel and spine fractures, indicate a higher probability of vascular damage, thus directing more definitive evaluation.  相似文献   
6.
Years of speculations about the nature of the elusive testis determining factor (TDF) of the Y chromosome have ended last year. A gene named SRY satisfies many criteria expected of the testis determining gene, and gives us a basis to understand molecular mechanisms of the testis differentiation. The different steps which gave rise to SRY cloning are described.  相似文献   
7.
Plasma gonadotropin FSH and LH, PRL, sex steroids (17-beta E2, E1, and P), SBP binding capacity, and urine estrogens (E1, E2, and E3) were measured in 485 premenopausal healthy women, subdivided according to smoking habits. The aim of the study was to verify if cigarette smoking influences sex hormone balance. Baseline PRL levels were significantly lower (P less than 0.002) in smoker (n = 174) than in nonsmoker (n = 311) women. No difference was found in the other parameters of the two groups, particularly in plasma and urine estrogenic pattern. Our data suggest that smoking directly affects PRL levels by involving the hypothalamic mechanism that regulates PRL secretion.  相似文献   
8.
9.
Infection of the oral mucous membrane is frequent in patients with removable prostheses, either totally of partially, and particularly when the prostheses is palatal. The principal etiological factor causing the infection is accepted to be "Candidas" aided by the presence of plaque bacteria (in patients with poor oral hygiene care), and a poor fit of the prostheses to the soft tissues. Treatment of the infection must proceed in the following order: a) use of effective medication against oral fungus such as Nystatin or Ketoconazole. b) Meticulous oral hygiene care in the mucous membrane as well as in the prostheses, but using the prostheses as little as possible during the treatment period. c) A total cure of the infection (denture stomatitis) before proceeding to the next phase of the treatment. d) Determination of the adjustment and occlusion of the prostheses in order to determine those areas of the prostheses which need to be refilled because of maladjustment of the prostheses to the soft tissues of the patient.  相似文献   
10.
The independent release of adenosine and adenine nucleotides upon electrical stimulation was studied in the innervated sartorius muscle of the frog after blockade of the extracellular catabolism of adenosine monophosphate (AMP) through exo-AMP deaminase and ecto-5-nucleotidase. Nerve stimulation (30 min, 0.2Hz) induced the release of both adenosine (19±3 pmol) and adenine nucleotides (101±7 pmol). Experiments performed in the presence of tubocurarine (5 M) to prevent purine release due to nerve-evoked muscle twitching, or under direct stimulation of the muscle in low calcium solutions to prevent pre-synaptic release of purines, showed that there was an evoked release of adenosine and adenine nucleotides both from the nerve endings and from the twitching muscle fibres. Removal of ecto-5-nucleotidase inhibition shows that the catabolism of adenine nucleotides released during stimulation contributes in about 50% to the amount of endogenous extracellular adenosine. When only one of the enzymes catabolizing AMP (ecto-5-nucleotidase or exo-AMP deaminase) was inhibited, the evoked release of adenine nucleotides was undetectable, suggesting that each enzyme is able to catabolize all the AMP formed from adenine nucleotides released upon stimulation. It is concluded that the concentration of endogenous extracellular adenosine is under the control of the relative activities of exo-AMP deaminase and ecto-5-nucleotidase.Brief accounts of some of the results in this study have been published previously (refs. [6, 7]).  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