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   63929篇
  免费   4734篇
  国内免费   395篇
耳鼻咽喉   636篇
儿科学   1647篇
妇产科学   1541篇
基础医学   7924篇
口腔科学   1561篇
临床医学   6419篇
内科学   14509篇
皮肤病学   833篇
神经病学   5013篇
特种医学   2169篇
外国民族医学   2篇
外科学   9770篇
综合类   1066篇
现状与发展   1篇
一般理论   103篇
预防医学   5262篇
眼科学   1855篇
药学   4520篇
中国医学   139篇
肿瘤学   4088篇
  2023年   269篇
  2022年   387篇
  2021年   1166篇
  2020年   727篇
  2019年   1011篇
  2018年   1250篇
  2017年   853篇
  2016年   976篇
  2015年   1146篇
  2014年   1790篇
  2013年   2824篇
  2012年   3776篇
  2011年   4121篇
  2010年   2364篇
  2009年   2218篇
  2008年   4017篇
  2007年   4230篇
  2006年   4035篇
  2005年   4141篇
  2004年   3850篇
  2003年   3465篇
  2002年   3425篇
  2001年   754篇
  2000年   634篇
  1999年   745篇
  1998年   797篇
  1997年   672篇
  1996年   549篇
  1995年   548篇
  1994年   500篇
  1993年   482篇
  1992年   545篇
  1991年   527篇
  1990年   437篇
  1989年   485篇
  1988年   431篇
  1987年   405篇
  1986年   372篇
  1985年   440篇
  1984年   444篇
  1983年   401篇
  1982年   543篇
  1981年   461篇
  1980年   504篇
  1979年   312篇
  1978年   326篇
  1977年   335篇
  1976年   271篇
  1975年   294篇
  1974年   246篇
排序方式: 共有10000条查询结果,搜索用时 640 毫秒
181.
Objectives
To explore medical students' use of computer tutorials embedded in a busy clinical setting; to demonstrate that such tutorials can increase knowledge gain over and above that attributable to the clinical rotation itself.
Methods
Six tutorials were installed on a computer placed in a central area in an emergency department. Each tutorial was made up of between 33 and 85 screens of information that include text, graphics, animations, and questions. They were designed to be brief (10 minutes), focused, interactive, and immediately relevant. The authors evaluated the intervention using quantitative research methods, including usage tracking, surveys of faculty and students, and a randomized pretest-posttest study.
Results
Over 46 weeks, 95 medical students used the tutorials 544 times, for an overall average of 1.7 times a day. The median time spent on completed tutorials was 11 minutes (average [SD], 14 [±12] minutes). Seventy-four students completed the randomized study. They completed 65% of the assigned tutorials, resulting in improved examination scores compared with the control (effect size, 0.39; 95% confidence interval = 0.15 to 0.62). Students were positively disposed to the tutorials, ranking them as "valuable." Fifty-four percent preferred the tutorials to small group teaching sessions with a preceptor. The faculty was also positive about the tutorials, although they did not appear to integrate the tutorials directly into their teaching.
Conclusions
Medical students on rotation in a busy clinical setting can and will use appropriately presented computer tutorials. The tutorials are effective in raising examination scores.  相似文献   
182.
183.
Patients with anorexia nervosa have neuroendocrine and behavioral alterations that starvation and weight loss are thought to cause, or contribute to, since they are reversed by weight restoration. We have found that anorexics have starvation-related disturbances of neuropeptide Y (NPY), corticotropin-releasing hormone (CRH), and beta-endorphin, as determined by their measurements in cerebrospinal fluid. The relationship between these neuropeptides and several symptoms in anorexia, together with findings in experimental animals, raise a possibility that changes in the activity of these neuropeptides contribute to neuroendocrine and behavioral alterations in anorexia. Specifically, a disturbance of central nervous system CRH activity is likely to be responsible for hypercortisolemia, while a disturbance of central nervous system NPY may contribute to amenorrhea. In addition, disturbances of these neuropeptides could contribute to other symptoms such as increased physical activity, hypotension, reduced sexual interest, depression, and pathological feeding behavior.  相似文献   
184.
Effect of pregnancy on panic attacks   总被引:1,自引:0,他引:1  
Three women with panic disorder showed marked improvement in their panic symptoms during pregnancy. Such effects might be due to pregnancy's blunting of the sympathoadrenal response to simple physiologic stimuli, effects on barbiturate receptors, or improvement in psychological functioning.  相似文献   
185.
This report describes a technique in which deep-seated CNS neoplasms, the volume and shape of which had been determined and stereotactically localized by computer reconstruction of CT data, were vaporized with a carbon dioxide laser attached to a stereotactic frame. The clinical results with 6 patients treated by this technique are presented.  相似文献   
186.
SMI-32, an antibody which recognizes the non-phosphorylated epitopes on the neurofilament proteins was used to study the morphological changes in the human striate cortex during postnatal development. Striate cortices from 12 autopsied patients with ages ranging from 1 day to 70 years were obtained. Using the avidin-biotin-peroxidase method, the first SMI-32 immunoreactive neurons were identified at sublayers Vb/VIa on the first postnatal day. At 5 months, the next group of neurons to develop immunoreactivity were in IVb. By 15 months, SMI-32 immunoreactive neurons were observed at III, IVa, IVb, V and VI. The changes in SMI-32 immunoreactivity (ir) were stabilized from 3 years and after. The SMI-32 ir in the striate cortex could be a useful morphological correlate for studying developmental diseases affecting the neocortex.  相似文献   
187.
188.
189.
Recurrence of hepatitis C (HCV) following liver transplantation is common. Herpesvirus reactivation following transplant may have an immunomodulatory effect resulting in increased HCV replication. We studied whether cytomegalovirus (CMV) and human herpesvirus-6 (HHV-6) may be associated with HCV recurrence and viral load after transplant. We prospectively followed 66 HCV liver-transplant recipients with serial viral load testing for CMV and HHV-6. Infection and viral load were correlated with the development of biopsy-proven HCV recurrence and HCV viral loads. Histologic recurrence of HCV occurred in 41/66 (62.1%) patients. In the primary analysis, CMV infection and disease, and HHV-6 infection were not associated with HCV recurrence. Peak CMV and HHV-6 viral loads were not significantly different in patients with and without recurrence. No correlation was observed between HCV viral loads at 1 and 3 months post-transplant and peak HHV-6 or CMV viral loads. In a subgroup analysis, HHV-6 infection was associated with the development of more severe recurrence (hepatitis and/or fibrosis score > or = 2) (p = 0.01). Also, fibrosis scores at last follow up were higher in patients with CMV disease (1.67 vs. 0.56; p = 0.016) and in patients with HHV-6 infection (1.18 vs. 0.55; p = 0.031). In conclusion, HHV-6 and CMV infection and viral load were not associated with increased overall rates of HCV recurrence or HCV viral load after liver transplantation but may be associated with more severe forms of recurrence.  相似文献   
190.
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