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   139964篇
  免费   10048篇
  国内免费   632篇
耳鼻咽喉   1744篇
儿科学   3643篇
妇产科学   2655篇
基础医学   17945篇
口腔科学   2943篇
临床医学   13720篇
内科学   28689篇
皮肤病学   1851篇
神经病学   12304篇
特种医学   5551篇
外科学   22331篇
综合类   2051篇
现状与发展   1篇
一般理论   175篇
预防医学   12748篇
眼科学   3004篇
药学   9862篇
  2篇
中国医学   182篇
肿瘤学   9243篇
  2023年   630篇
  2022年   907篇
  2021年   2613篇
  2020年   1506篇
  2019年   2457篇
  2018年   2996篇
  2017年   2159篇
  2016年   2317篇
  2015年   2794篇
  2014年   4122篇
  2013年   6210篇
  2012年   9074篇
  2011年   9671篇
  2010年   5389篇
  2009年   4922篇
  2008年   8614篇
  2007年   9250篇
  2006年   8791篇
  2005年   8954篇
  2004年   8578篇
  2003年   8071篇
  2002年   7854篇
  2001年   1432篇
  2000年   1193篇
  1999年   1533篇
  1998年   1679篇
  1997年   1356篇
  1996年   1291篇
  1995年   1269篇
  1994年   1071篇
  1993年   1048篇
  1992年   931篇
  1991年   993篇
  1990年   843篇
  1989年   805篇
  1988年   828篇
  1987年   808篇
  1986年   811篇
  1985年   887篇
  1984年   960篇
  1983年   902篇
  1982年   1162篇
  1981年   1184篇
  1980年   989篇
  1979年   673篇
  1978年   703篇
  1977年   622篇
  1976年   535篇
  1975年   489篇
  1974年   492篇
排序方式: 共有10000条查询结果,搜索用时 437 毫秒
101.
102.
103.
104.
105.
Summary Cytosine arabinsodie (ara-C) and etoposide (VP-16) display synergy in the laboratory. Twenty-six patients participated in a phase I study of high-dose ara-C in combination with VP-16. The dose of VP-16 was held constant at 50 mg/m2 as an intermittent infusion over 33 h; escalating doses of ara-C were given as infusions during hours 9–12 and 21–24. Myelosuppression was the dose-limiting toxicity and occurred with doses considerably less than those expected from studies of the two drugs as single agents. The suggested initial doses for phase II trials with this schedule are 750 mg/m2×2 doses of ara-C and 50 mg/m2 of VP-16. Nonhematologic toxicity was minimal; therefore, further dose escalation is feasible in patients in whom myelosuppression is acceptable.Supported in part by grants from the National Cancer Institute (CA-12197 and CA-09422) and the American Cancer Society CF-85-182  相似文献   
106.
OBJECTIVE: Traditional assessments of the microbial flora associated with acute bacterial rhinosinusitis have relied on maxillary sinus punctures (taps) and culture. These taps are now considered the gold standard for obtaining cultures and are used as the method of identifying bacterial pathogens in antimicrobial trials. Maxillary sinus taps are limited by discomfort to the patients and technical concerns. Because of these factors, the standard of performing taps has limited antibiotic trials and microbial surveillance. Alternatives to maxillary sinus taps have been explored. STUDY DESIGN: We conducted a retrospective, systematic review of the literature from 1950 to 2000 of articles comparing culture techniques in the nose and paranasal sinuses for acute bacterial rhinosinusitis. RESULTS: Nasal cultures have poor correlation to maxillary sinus cultures, whereas there is 60% to 85% concordance between endoscopically guided middle meatal cultures and maxillary sinus cultures. These studies, however, are all limited by small sample sizes and therefore are inadequate to make any concrete recommendations regarding the relative role of endoscopically guided middle meatal cultures as a formal method of pathogen identification in acute bacterial rhinosinusitis. CONCLUSION: A formal prospective study with sufficient sample size to assess the concordance between the microbial flora of the maxillary sinus punctures and middle meatal cultures in acute rhinosinusitis is recommended.  相似文献   
107.
This paper reports the proceedings of the discussion panel assigned to look at clinical aspects of quality in emergency medicine. One of the seven stated objectives of the Academic Emergency Medicine consensus conference on quality in emergency medicine was to educate emergency physicians regarding quality measures and quality improvement as essential aspects of the practice of emergency medicine. Another topic of interest was a discussion of the value of information technology in facilitating quality care in the clinical practice of emergency medicine. It is important to note that this is not intended to be a comprehensive review of this extensive topic, but instead is designed to report the discussion that occurred at this session of the consensus conference.  相似文献   
108.
These experiments examined the effects, on retention, of posttraining intra-amygdala administration of norepinephrine (NE), and propranolol. Rats were trained on a one-trial step-through inhibitory avoidance task and tested for retention 24 h later. Injections were administered bilaterally (1.0 microliter/injection) through chronically-implanted cannulae. Low doses of NE (0.1 or 0.3 microgram) administered shortly after training enhanced retention while higher doses (1.0 or 5.0 micrograms) were ineffective. Retention was not affected by NE administered 3 h after training. The effect of intra-amygdala NE on retention is blocked by simultaneous administration of propranolol (0.2 microgram). This finding suggests that the memory-enhancing effect of NE may be mediated by beta-receptors. Posttraining intra-amygdala NE also attenuated the retention deficit produced by adrenal demedullation. Further, intra-amygdala injections of propranolol (0.2 microgram) blocked the enhancing effect, on retention, of posttraining s.c. injections of epinephrine. These findings suggest that activation of noradrenergic receptors in the amygdala may be involved in memory processing and may play a role in the memory-modulating effect of peripheral epinephrine.  相似文献   
109.
110.
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