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   63406篇
  免费   4590篇
  国内免费   334篇
耳鼻咽喉   636篇
儿科学   1603篇
妇产科学   1541篇
基础医学   7863篇
口腔科学   1538篇
临床医学   6361篇
内科学   14396篇
皮肤病学   809篇
神经病学   5001篇
特种医学   1916篇
外国民族医学   2篇
外科学   9757篇
综合类   1016篇
现状与发展   1篇
一般理论   104篇
预防医学   5276篇
眼科学   1860篇
药学   4436篇
中国医学   139篇
肿瘤学   4075篇
  2023年   293篇
  2022年   463篇
  2021年   1160篇
  2020年   725篇
  2019年   1012篇
  2018年   1244篇
  2017年   848篇
  2016年   968篇
  2015年   1136篇
  2014年   1775篇
  2013年   2813篇
  2012年   3778篇
  2011年   4122篇
  2010年   2350篇
  2009年   2193篇
  2008年   4008篇
  2007年   4195篇
  2006年   4026篇
  2005年   4114篇
  2004年   3842篇
  2003年   3454篇
  2002年   3416篇
  2001年   732篇
  2000年   625篇
  1999年   722篇
  1998年   744篇
  1997年   609篇
  1996年   493篇
  1995年   491篇
  1994年   466篇
  1993年   440篇
  1992年   534篇
  1991年   512篇
  1990年   418篇
  1989年   440篇
  1988年   396篇
  1987年   374篇
  1986年   359篇
  1985年   421篇
  1984年   434篇
  1983年   394篇
  1982年   529篇
  1981年   445篇
  1980年   485篇
  1979年   302篇
  1978年   321篇
  1977年   322篇
  1976年   264篇
  1975年   288篇
  1974年   247篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
OBJECTIVE: To determine the natural history of colonization with vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA), and resistant gram-negative bacilli among long-term-care facility (LTCF) residents. DESIGN: Observational cohort study. SETTING: A 355-bed LTCF with a ventilator unit and a subacute unit. PARTICIPANTS: Residents with colonization or infection with VRE, MRSA, or resistant gram-negative bacilli housed at the LTCF between December 1, 1999, and February 29, 2000. METHODS: Cultures of clinical and surveillance sites were performed at regular intervals. Charts were reviewed for clinical characteristics associated with clearance of colonization. Kaplan-Meier curves were constructed to analyze the number of days to clearance of colonization. RESULTS: Forty-nine residents had 65 episodes of colonization (27 VRE, 30 MRSA, and 8 resistant gram-negative bacilli). Eighteen (28%) of the episodes cleared. The clearance rate was 2.7 episodes per 1,000 person-days. Clearance occurred significantly more often with resistant gram-negative bacilli colonization compared with VRE or MRSA colonization (6 [75%] vs 12 [21%]; P = .007; relative risk, 4.17; 95% confidence interval, 1.26 to 11.8). There was a trend toward longer use of antimicrobial agents among residents with persistent colonization. Infections occurred most frequently with MRSA. The urinary tract was the most common site of infection. CONCLUSION: Among LTCF residents, colonization with resistant gram-negative bacilli is four times more likely to clear than colonization with VRE or MRSA. Performance of surveillance cultures at regular intervals may reduce the need for contact precautions for LTCF residents with resistant gram-negative bacilli colonization.  相似文献   
73.
The purpose of this study is to identify correlates of dental student stress. Associations between characteristics of dental students and their stress levels are examined, along with the association of stress with drug use and health problems. A total of 300 out of 315 dental students completed a questionnaire that measured the frequency and stressfulness of 31 stressors; drug use; health problems; and student characteristics including Type A behavior, career commitment, demographics, and lifestyle variables. Characteristics that were associated with a higher stress level were a higher level of Type A behavior and lower level of career commitment. Greater stress was also associated with a greater frequency of health problems. The results suggest an interactional stress model in which the personalities and attitudes of students are important mediators of the stress response.  相似文献   
74.
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   
75.
76.
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   
77.
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   
78.
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   
79.
80.
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