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   1048篇
  免费   75篇
  国内免费   1篇
耳鼻咽喉   4篇
儿科学   23篇
妇产科学   36篇
基础医学   264篇
口腔科学   6篇
临床医学   68篇
内科学   139篇
皮肤病学   221篇
神经病学   109篇
特种医学   20篇
外科学   89篇
综合类   7篇
预防医学   41篇
眼科学   9篇
药学   51篇
中国医学   1篇
肿瘤学   36篇
  2022年   13篇
  2021年   19篇
  2020年   25篇
  2019年   27篇
  2018年   19篇
  2017年   23篇
  2016年   23篇
  2015年   37篇
  2014年   21篇
  2013年   43篇
  2012年   77篇
  2011年   72篇
  2010年   40篇
  2009年   33篇
  2008年   63篇
  2007年   48篇
  2006年   51篇
  2005年   56篇
  2004年   43篇
  2003年   40篇
  2002年   40篇
  2001年   39篇
  2000年   22篇
  1999年   16篇
  1998年   7篇
  1997年   3篇
  1996年   9篇
  1995年   5篇
  1992年   14篇
  1991年   12篇
  1990年   9篇
  1989年   14篇
  1988年   15篇
  1987年   17篇
  1986年   17篇
  1985年   9篇
  1984年   11篇
  1983年   6篇
  1981年   3篇
  1979年   17篇
  1978年   6篇
  1977年   9篇
  1976年   5篇
  1975年   3篇
  1974年   4篇
  1972年   5篇
  1971年   5篇
  1970年   4篇
  1969年   7篇
  1967年   3篇
排序方式: 共有1124条查询结果,搜索用时 46 毫秒
1.
We report on a man without any symptoms until the age of 29 years when a ventricular tachyarrhythmia occurred for the first time. There were electrocardiographic signs of a previous myocardial infarction of the anterior wall, but there had not even been any episode of angina pectoris. The cause was the anomalous origin of the left coronary artery from the pulmonary trunk (Bland-White-Garland syndrome). Therapy consisted of ligation of the left coronary artery and the implantation of an aortocoronary vein graft to the left coronary artery in order to reinstall a two-coronary system. Diagnosis is easily made by coronary angiography. At a 3-year follow-up there was an increase of the ejection fraction/cardiac output, a stable sinus rhythm, and an improved physical endurance.  相似文献   
2.
To study the effects of bacteremia on skeletal muscle leucine (LEU) metabolism, mongrel dogs were infused with normal saline or Escherichia coli (10(9)/kg). After a bolus dose (3.6 microCi), L(1-carbon 14) LEU (0.3 microCi/min) was infused directly into the isolated, constant-flow, in vivo gracilis muscle. Arteriovenous differences for amino acids, labeled and unlabeled LEU and alpha-ketoisocaproic acid (KIC), and labeled carbon dioxide were measured at ten-minute intervals for one hour. Bacteremia increased the net release of amino acids and total N2 from muscle. Moreover, plasma LEU that was deaminated and released as KIC was increased, and there was also an increase in decarboxylated plasma LEU during bacteremia. Despite the marked increase in KIC release from skeletal muscle during bacteremia, arterial concentrations were not significantly different from those of controls. An unchanged arterial plasma KIC concentration associated with a marked increase in KIC released from skeletal muscle indicates an increase in LEU metabolism, most likely in the liver. Thus, the increased skeletal muscle catabolism is not a futile cycle but rather an essential event to meet the increased metabolic needs of the body during bacteremia.  相似文献   
3.
4.
5.
Heterotopic cervical salivary gland tissue was found in a 4-yr-old girl with branchial and otologic abnormalities. Her mother and sister also had heterotopic cervical salivary tissue in association with anomalies that suggest the branchio-otorenal (BOR) syndrome. Heterotopic cervical salivary gland tissue may result from abnormal branchial development.  相似文献   
6.
In 1999, mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2) were first reported in patients with Rett syndrome (RTT). The MECP2 gene is located at Xq28 and consists of 4 exons. About 80-90 % of the classic RTT patients harbor mutations in the coding region of MECP2, while the molecular cause is unknown in the remaining 10-20%. Several groups have searched for large rearrangements within the MECP2 and the results indicate that a fraction of MECP2-negative RTT cases has large deletions of the MECP2. In this study we have used the Multiplex Ligation-dependent Probe Amplification (MLPA) technique to screen 45 RTT patients, who have previously been tested negative for mutations in the coding region of MECP2. The MECP2-MLPA is a semi-quantitative multiplex PCR approach. It determines the relative number of copies of each MECP2 exon. With this approach we detected seven RTT patients with genomic deletions and further characterized the deletions using real time quantitative PCR (qPCR) and long-range PCR. The seven patients were given a severity score and their X chromosome inactivation profiles were determined in order to identify a possible genotype-phenotype correlation. The results from this study indicate that large deletions in MECP2 cause classic RTT.  相似文献   
7.
A newly developed enzyme immunoassay (EIA) was used to detect the presence of pneumococcal teichoic and lipoteichoic acids in cerebrospinal fluid (CSF) from patients with Streptococcus pneumoniae meningitis who were being treated with antibiotics. All initial CSF samples, which on culture grew S. pneumoniae, were positive in the EIA. A total of 14 subsequent culture-negative samples gave clear signals in the EIA up to day 15 after the onset of antibiotic treatment. For 11 CSF specimens, culture, microscopy, and latex agglutination were negative while the EIA detected pneumococcal antigens. The EIA did not react either with CSF of patients with meningitis caused by bacteria other than S. pneumoniae or by viral pathogens. In conclusion, this EIA can be a valuable tool for the diagnosis of S. pneumoniae meningitis from CSF samples in cases in which prior antimicrobial therapy minimizes the usefulness of culture or other antigen detection tests.  相似文献   
8.
9.
Tissue inhibitor of metalloproteinases 1 (TIMP-1) inhibits several proteinases including a disintegrin and metalloproteinase 10 (ADAM10), a major alpha-secretase that cleaves the beta-amyloid precursor protein within its amyloidogenic Abeta domain. The gene encoding TIMP-1 (TIMP 1) maps to the short arm of the X chromosome, in a region previously suggested as conferring genetic susceptibility for Alzheimer's disease (AD). To determine whether genetic variability of TIMP 1 contributes to the pathogenesis of AD, we analysed one single nucleotide polymorphism within TIMP 1 and one single nucleotide polymorphism in the 5'-untranslated region of TIMP 1 in patients with AD and control subjects from two independent and ethnically different populations. We did not observe any association between TIMP 1 genotypes and the diagnosis of AD in men or women. We also measured TIMP-1 protein levels in the cerebrospinal fluid of patients with AD, healthy control subjects, and patients with other neurological disorders. TIMP-1 levels were similar in all groups. In addition, no significant differences were observed after stratification for TIMP 1 genotypes. Our data show that neither genetic variability nor protein levels of TIMP-1 are associated with AD.  相似文献   
10.
Major depression is conditionally linked to a polymorphism of the human serotonin transporter gene (SLC6A4). During the presentation of aversive, but not pleasant, pictures, healthy carriers of the SLC6A4 short (s) allele showed stronger activation of the amygdala on functional magnetic resonance imaging. s carriers also showed greater coupling between the amygdala and the ventromedial prefrontal cortex, which may contribute to the abnormally high activity in the amygdala and medial prefrontal cortex seen in major depression.  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