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   8542篇
  免费   755篇
  国内免费   18篇
耳鼻咽喉   226篇
儿科学   308篇
妇产科学   224篇
基础医学   1068篇
口腔科学   201篇
临床医学   961篇
内科学   1743篇
皮肤病学   241篇
神经病学   658篇
特种医学   400篇
外科学   1506篇
综合类   168篇
一般理论   8篇
预防医学   646篇
眼科学   148篇
药学   328篇
肿瘤学   481篇
  2021年   92篇
  2018年   101篇
  2017年   87篇
  2016年   80篇
  2015年   111篇
  2014年   138篇
  2013年   227篇
  2012年   294篇
  2011年   305篇
  2010年   185篇
  2009年   170篇
  2008年   270篇
  2007年   336篇
  2006年   333篇
  2005年   336篇
  2004年   294篇
  2003年   338篇
  2002年   312篇
  2001年   266篇
  2000年   288篇
  1999年   254篇
  1998年   87篇
  1997年   88篇
  1996年   91篇
  1995年   87篇
  1993年   86篇
  1992年   241篇
  1991年   239篇
  1990年   222篇
  1989年   247篇
  1988年   200篇
  1987年   212篇
  1986年   206篇
  1985年   195篇
  1984年   172篇
  1983年   118篇
  1982年   88篇
  1979年   142篇
  1978年   107篇
  1976年   83篇
  1975年   78篇
  1974年   96篇
  1973年   150篇
  1972年   88篇
  1971年   101篇
  1970年   107篇
  1969年   97篇
  1968年   81篇
  1967年   81篇
  1966年   81篇
排序方式: 共有9315条查询结果,搜索用时 15 毫秒
41.
Clonal chromosomal abnormalities in cutaneous T-cell lymphoma   总被引:1,自引:0,他引:1  
Chromosome analysis from stimulated and unstimulated lymphocytes of blood, skin, and lymph nodes demonstrated a clonal chromosomal abnormality in eight of 46 patients with cutaneous T-cell lymphoma (CTCL). Nonclonal abnormalities were found in nine other patients. Unstimulated lymph node cultures identified the highest proportion of clonal changes. Clonal changes were found most often in patients with advanced disease, and in patients who tested positive with a monoclonal antibody previously shown to detect the T-cells involved in CTCL. Analysis of the eight abnormal clones and seven others found before or since this consecutive series showed that identifiable changes involving the known sites of T-cell receptor genes on chromosomes #7 and #14 were not usually present. An association between CTCL and chromosome rearrangements of chromosome #10 is suggested both from our cases and those found in the literature. This observation is of interest because this chromosome contains the gene for the interleukin-2 receptor.  相似文献   
42.
43.
44.
Adult supraglottitis. A prospective analysis   总被引:1,自引:0,他引:1  
J Shapiro  R D Eavey  A S Baker 《JAMA》1988,259(4):563-567
  相似文献   
45.
BACKGROUND: Coronary artery calcium (CAC) provides evidence of coronary atherosclerosis and has significant prognostic power. Although prior studies have documented a relationship between CAC and hemodynamically significant coronary artery stenosis, the results have not been conclusive. METHODS AND RESULTS: We evaluated 126 consecutive patients who underwent electron beam computed tomography CAC scoring by use of the Agatston method and stress myocardial perfusion imaging (MPI) within 3 months of each other. The analysis revealed no correlation between absolute CAC score and age- and gender-adjusted CAC scores with MPI. Overall, 18% of patients had abnormal MPI results irrespective of their CAC. CONCLUSION: CAC scoring and stress MPI should be thus considered complementary approaches rather than exclusionary in the evaluation of the patient at risk for coronary artery disease.  相似文献   
46.
Nitrous oxide anesthesia has been implicated as contributing to the development of delayed tension pneumocephalus following surgery performed in the sitting position. The authors tested the hypothesis that withdrawal of nitrous oxide anesthesia administered during formation of an intracranial gas cavity would lead to a decrease in intracranial pressure (ICP) as N2O diffuses from the cavity back into the blood. Ten halothane-anesthetized rabbits were prepared for measurement of supracortical ICP and arterial blood pressure (BP) and for intracranial volume alterations via a cisterna magna infusion catheter. Hyperventilation (Paco2 = 28-30 mmHg) and mannitol were used to shrink the brain to accommodate intracranial infusion of either air or lactated Ringer's (LR) solution, which was used to elevate ICP to between 10-15 mmHg from a baseline ICP of 2.1 +/- 2.5 mmHg over a period of 8 to 10 min. Following stabilization at an elevated ICP, inhalation of nitrous oxide (75%) was either initiated or withdrawn (if already present during the induced ICP increase) and the subsequent changes in mean ICP and BP were recorded. Following ICP elevation with LR to 10 +/- 1 mmHg, initiation of 75% N2O administration resulted in no change in ICP and modest increases (P less than 0.05) in BP and cerebral perfusion pressure (CPP = BP - ICP) after 4 min. However, when ICP was raised (to 12 +/- 3.5 mmHg) with intracranial air infusion, subsequent initiation of 75% N2O inhalation caused an abrupt ICP increase to 22.3 +/- 9 mmHg (from control P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
47.
A hard contact lens penetrated the right upper lid at the level of the aponeurosis of the levator palpebral superior's muscle. Later tumor-like symptoms developed of a hard movable mass with blepharoptosis.  相似文献   
48.
49.
There is growing evidence that a spectrum of chondrodysplasias are caused by mutations in the gene coding for type II collagen. The basic molecular defect in diastrophic dysplasia has not been defined, but it appears not to be in collagen type II. Cartilage contains other tissue-specific collagens, types IX, X, and XI, but no mutations have yet been found in their genes in clinical disease. Type IX collagen is hypothesized to play a role in the regulation of type II collagen fibril organization and structure in cartilage extracellular matrix. In this study, we have examined iliac crest growth cartilage from a patient with diastrophic dysplasia. Although collagen fibrils were markedly increased in diameter on transmission electron microscopy, type II collagen appeared to be normal biochemically. Type XI collagen was also normal. However, type IX collagen appeared abnormal on sodium dodecyl sulfate polyacrylamide gel electrophoresis with a pronounced excess of the COL1 domain of the molecule in pepsin extracts. The findings point to an abnormality in structure or metabolism of type IX collagen in diastrophic dysplasia. © 1994 Wiley-Liss, Inc.  相似文献   
50.
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