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   348771篇
  免费   43968篇
  国内免费   8200篇
耳鼻咽喉   8035篇
儿科学   8186篇
妇产科学   5494篇
基础医学   32281篇
口腔科学   5928篇
临床医学   47198篇
内科学   81113篇
皮肤病学   12350篇
神经病学   28800篇
特种医学   16144篇
外国民族医学   37篇
外科学   63843篇
综合类   11173篇
现状与发展   91篇
一般理论   38篇
预防医学   18508篇
眼科学   8282篇
药学   20040篇
  60篇
中国医学   5331篇
肿瘤学   28007篇
  2024年   967篇
  2023年   6644篇
  2022年   6725篇
  2021年   11260篇
  2020年   10824篇
  2019年   7715篇
  2018年   13514篇
  2017年   12479篇
  2016年   14180篇
  2015年   16756篇
  2014年   25335篇
  2013年   26410篇
  2012年   21943篇
  2011年   22006篇
  2010年   19916篇
  2009年   21979篇
  2008年   17048篇
  2007年   14905篇
  2006年   16629篇
  2005年   13319篇
  2004年   10819篇
  2003年   8961篇
  2002年   8062篇
  2001年   8588篇
  2000年   7455篇
  1999年   7033篇
  1998年   5511篇
  1997年   5065篇
  1996年   4607篇
  1995年   4327篇
  1994年   2934篇
  1993年   2274篇
  1992年   2758篇
  1991年   2614篇
  1990年   2145篇
  1989年   2104篇
  1988年   1858篇
  1987年   1641篇
  1986年   1483篇
  1985年   1303篇
  1984年   959篇
  1983年   813篇
  1982年   693篇
  1981年   631篇
  1980年   527篇
  1979年   593篇
  1978年   532篇
  1977年   553篇
  1975年   430篇
  1972年   439篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
62.
Beta-adrenergic receptor density on T cells from healthy humans is greatest on suppressor cells (CD8+, CD28-) and the effect of catecholamines, secreted by the sympathetic nervous system, predominates on this subset. The sympathetic skin response, a measure of sympathetic nervous system function, is absent in most patients with chronic progressive multiple sclerosis (MS). We measured beta-adrenergic receptor density on suppressor cells, cytotoxic cells, and monocytes from patients with chronic progressive MS and healthy control subjects. Control receptor density on suppressor cells was 2.8 +/- 0.3 fmol/10(6) cells versus a density of 5.1 +/- 0.7 fmol/10(6) cells for patients. Cytotoxic cell (CD8+, CD28+) receptor density was 1.4 +/- 0.4 fmol/10(6) cells in control subjects and 0.9 +/- 0.3 fmol/10(6) cells in the patients. Monocytes displayed beta-adrenergic receptor densities of 2.6 +/- 0.4 fmol/10(6) cells in normal individuals and 2.7 +/- 0.4 fmol/10(6) cells in the patient group. CD8 lymphocyte beta-adrenergic receptor densities in patients with relapsing-remitting and those with stable MS were not different from control values, yet were significantly less than the values for patients with chronic progressive MS. We find that mononuclear cells from healthy control subjects and patients with chronic progressive MS proliferate in response to 200 units/ml of recombinant human interleukin-2 (IL-2) similarly. However, IL-2 treatment increased beta-adrenergic receptor density on normal mononuclear cells, but failed to increase it on mononuclear cells from patients with chronic progressive MS.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
63.
A case of Goldenhar’s Syndrome in a 10 year old girl is reported. The unusual features are the absence of epibulbar dermoid which is one of the major hallmarks of the Syndrome and the presence of an associated Cyanotic Heart disease.  相似文献   
64.
65.
BACKGROUND AND PURPOSE: The catastrophic Chi-Chi earthquake of September 21, 1999 in Taiwan provided a unique opportunity to study the disaster's psychiatric impact on survivors. This study assessed the development of psychiatric disorders among residents in a Taiwanese village near the epicenter of the earthquake within 6 months of the disaster. METHODS: A total of 442 of the 602 actual living residents of Tong-Chi village who were over 16 years of age and were present in the community at the time of the earthquake were included in this population survey. Subjects were interviewed by psychiatrists using the Mini-International Neuropsychiatric Interview and questionnaires to collect demographic information and risk factors for psychiatric disorders 4 to 6 months after the earthquake. RESULTS: The prevalence rates were 9.5% for current major depression, 2.8% for past major depressive episode, and 7.9% for post-traumatic stress disorder (PTSD). Females had significantly higher rates of most psychiatric disorders. After controlling for covariates, the significant risk factors for PTSD were female gender and having sought medical service after the earthquake. Significant risk factors for major depressive episode were divorced/widowed status, education level equal to or below primary school, and prominent house damage. CONCLUSION: This population survey of earthquake disaster survivors found an increased prevalence of psychiatric disorders after exposure to a catastrophic earthquake. These results highlight the need for prompt therapeutic attention to residents of earthquake disaster areas after the event.  相似文献   
66.
ABSTRACT: Klinefelter syndrome occurs in approximately 1 in 1000 males. A 4-year-old boy presented with precocious puberty and an anterior mediastinal mass. Serum alpha-fetoprotein and human chorionic gonadotropin levels were mildly increased. Computed tomography revealed a germ cell tumor (GCT) of the mediastinum. Complete resection of the tumor was performed. Histologic analysis revealed an immature teratoma. Males with Klinefelter syndrome develop GCTs at a rate 50 times higher than unaffected males. This case report calls attention to the need to rule out Klinefelter syndrome in boys who present with precocious puberty and a mediastinal GCT.  相似文献   
67.
Obese Zucker rats are less responsive than their lean littermates to the effects of cholecystokinin-octapeptide on satiety and pancreatic growth and exocrine function. We hypothesized that the hyperphagia observed in obese Zucker rats may be caused by a decreased pyloric contractile response to cholecystokinin, resulting in an increased rate of gastric emptying, decreased postprandial gastric distention, and thus decreased satiety. Pyloric muscle strips from six obese Zucker rats and six lean littermates were mounted in separate tissue baths and isometric contraction was measured in response to acetylcholine and cholecystokinin-octapeptide. The dose-response curves for acetylcholine-and cholecystokinin-octapeptide-stimulated pyloric muscle contraction were similar for both the obese and the lean rats. (For cholecystokinin, D50 obese=4.0±0.6 nM, D50 lean=3.4±0.2 nM;P=0.16). We conclude that the decreased satiety response to cholecystokinin-octapeptide observed in obese Zucker rats is not secondary to a decreased pyloric responsiveness to cholecystokinin.This work was supported by NIH grant AM28303-03.  相似文献   
68.
69.
70.
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