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   46139篇
  免费   4220篇
  国内免费   120篇
耳鼻咽喉   509篇
儿科学   1396篇
妇产科学   1113篇
基础医学   6697篇
口腔科学   936篇
临床医学   5139篇
内科学   9091篇
皮肤病学   508篇
神经病学   3630篇
特种医学   1259篇
外国民族医学   3篇
外科学   6431篇
综合类   1014篇
一般理论   58篇
预防医学   4454篇
眼科学   1271篇
药学   3667篇
中国医学   121篇
肿瘤学   3182篇
  2023年   246篇
  2022年   378篇
  2021年   875篇
  2020年   531篇
  2019年   827篇
  2018年   915篇
  2017年   700篇
  2016年   822篇
  2015年   923篇
  2014年   1373篇
  2013年   1988篇
  2012年   2831篇
  2011年   2985篇
  2010年   1654篇
  2009年   1409篇
  2008年   2486篇
  2007年   2676篇
  2006年   2720篇
  2005年   2704篇
  2004年   2572篇
  2003年   2309篇
  2002年   2126篇
  2001年   873篇
  2000年   778篇
  1999年   841篇
  1998年   555篇
  1997年   509篇
  1996年   474篇
  1995年   441篇
  1994年   379篇
  1993年   356篇
  1992年   603篇
  1991年   559篇
  1990年   507篇
  1989年   472篇
  1988年   481篇
  1987年   448篇
  1986年   438篇
  1985年   448篇
  1984年   371篇
  1983年   346篇
  1982年   307篇
  1981年   301篇
  1980年   236篇
  1979年   310篇
  1978年   269篇
  1977年   243篇
  1976年   213篇
  1974年   248篇
  1973年   259篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
1.
Hepatic NADPH-cytochrome P450 oxidoreductase null (HRN?) mice exhibit normal hepatic and extrahepatic biotransformation enzyme activities when compared to wild-type (WT) mice, but express no functional hepatic cytochrome P450 activities. When incubated in vitro with [14C]-diclofenac, liver microsomes from WT mice exhibited extensive biotransformation to oxidative and glucuronide metabolites and covalent binding to proteins was also observed. In contrast, whereas glucuronide conjugates and a quinone-imine metabolite were formed when [14C]-diclofenac was incubated with HRN? mouse liver, only small quantities of P450-derived oxidative metabolites were produced in these samples and covalent binding to proteins was not observed. Livers from vehicle-treated HRN? mice exhibited enhanced lipid accumulation, bile duct proliferation, hepatocellular degeneration and necrosis and inflammatory cell infiltration, which were not present in livers from WT mice. Elevated liver-derived alanine aminotransferase, glutamate dehydrogenase and alkaline phosphatase activities were also observed in plasma from HRN? mice. When treated orally with diclofenac for 7 days, at 30 mg/kg/day, the severities of the abnormal liver histopathology and plasma liver enzyme findings in HRN? mice were reduced markedly. Oral diclofenac administration did not alter the liver histopathology or elevate plasma enzyme activities of WT mice. These findings indicate that HRN? mice are valuable for exploration of the role played by hepatic P450s in drug biotransformation, but poorly suited to investigations of drug-induced liver toxicity. Nevertheless, studies in HRN? mice could provide novel insights into the role played by inflammation in liver injury and may aid the evaluation of new strategies for its treatment.  相似文献   
2.
随着婴儿潮、人口老龄化及新技术的广泛应用,人们对听力保健的需求显著增加。在美国,听力保健服务由助听设备专员、耳鼻喉科医生和听力师3类人员提供,其中听力师提供除医疗、手术外宽泛的听力保健服务。美国的听力保健服务体系及听力师教育体系经历了一个渐进的过程:20年前对从业人员的学历要求是听力学硕士,随着对服务质量要求的提高和服务范围的扩大,美国听力师逐渐要求专业博士学位(Au.D),毕业后还需3~4年的专门教育才能成为一名听力师。听力师教育有统一的标准,大学课程要通过听力教育认证委员会(the Accreditation Commission for Audiology Education, ACAE)或学术认证委员会(the Council on Academic Accreditation,CAA)的多程序严格的认证才能被承认。美国听力师需求存在巨大缺口,但是各国听力学教育标准不统一及听力师收入与教育投资不匹配,阻碍了更多的人进入这一领域。美国试图通过改变教育模式,降低教育成本及革新教学方法等改善听力师教育状况,但是听力师教育体系远未完善。  相似文献   
3.
Abstract

Objectives: This study examined word use as an indicator of interpersonal positive reframing in daily conversations of couples coping with breast cancer and as a predictor of stress.

Design: The Electronically Activated Recorder (EAR) and Linguistic Inquiry and Word Count (LIWC) were used to examine naturally occurring word use conceptually linked to positive reframing (positive emotion, negative emotion, and cognitive processing words).

Sample: Fifty-two couples coping with breast cancer.

Methods: Couples wore the EAR, a device participants wear, that audio-recorded over one weekend (>16,000 sound files), and completed self-reports of positive reframing (COPE) and stress (Perceived Stress Scale). LIWC, a software program, measured word use.

Findings: Both partners’ word use (i.e., positive emotion and cognitive processing words) was associated with their own reported positive reframing, and spouses’ word use was also indicative of patients’ positive reframing. Results also revealed that, in general, words indicating positive reframing predicted lower levels of stress.

Conclusions: Findings supported the hypothesis that partners—and particularly spouses of breast cancer patients—may assist each other’s coping by positively reframing the cancer experience and other negative experiences in conversation.  相似文献   
4.
5.
6.
7.
8.
9.
10.
BACKGROUND: Solid-organ transplantation has become the treatment of choice for patients with end-stage renal disease, end-stage liver failure, and some patients with type 1 diabetes mellitus. Similarly, surgical expertise and mechanical improvements have led to significant advances in laparoscopic surgery. Laparoscopic interventions are sometimes not pursued in transplant recipients due to the lack of strong supporting evidence for the use of laparoscopic techniques in these patients. METHODS: Using an extensive literature search, we review herein the available data on the utility of laparoscopic interventions in transplant recipients, with particular attention to the risks and benefits, indications, and contraindications for this complex patient population. RESULTS: Although randomized trials are few, multiple case reports indicate that many transplant recipients have benefited from laparoscopic interventions. CONCLUSION: The well-known benefits of laparoscopy could be extended to transplant recipients.  相似文献   
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