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   5130篇
  免费   372篇
  国内免费   24篇
耳鼻咽喉   35篇
儿科学   106篇
妇产科学   122篇
基础医学   531篇
口腔科学   117篇
临床医学   983篇
内科学   764篇
皮肤病学   104篇
神经病学   467篇
特种医学   278篇
外国民族医学   1篇
外科学   555篇
综合类   39篇
一般理论   5篇
预防医学   888篇
眼科学   47篇
药学   300篇
中国医学   2篇
肿瘤学   182篇
  2023年   34篇
  2021年   57篇
  2020年   60篇
  2019年   65篇
  2018年   97篇
  2017年   69篇
  2016年   86篇
  2015年   84篇
  2014年   148篇
  2013年   235篇
  2012年   226篇
  2011年   259篇
  2010年   179篇
  2009年   147篇
  2008年   222篇
  2007年   200篇
  2006年   233篇
  2005年   245篇
  2004年   237篇
  2003年   208篇
  2002年   222篇
  2001年   84篇
  2000年   67篇
  1999年   99篇
  1998年   76篇
  1997年   69篇
  1996年   86篇
  1995年   81篇
  1994年   94篇
  1993年   68篇
  1992年   88篇
  1991年   85篇
  1990年   65篇
  1989年   68篇
  1988年   63篇
  1987年   54篇
  1986年   40篇
  1985年   61篇
  1984年   53篇
  1983年   42篇
  1979年   33篇
  1978年   37篇
  1977年   35篇
  1976年   36篇
  1974年   32篇
  1972年   33篇
  1970年   34篇
  1969年   34篇
  1967年   31篇
  1966年   35篇
排序方式: 共有5526条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
Given that prevention is crucial to long healthy life and restraining escalating health care costs, this study examines social media and networking (SM&N) needs among health consumers regarding preventive health. Results showed the most important SM&N needs included: education about health issues, connecting to a support group, knowing the implications of health condition, opportunities and understanding of preventive health care, and tracking physical activity. Among demographic groups women, younger aged groups, and African Americans considered SM&N needs to be more important. Homemakers indicated greatest need for information about health issues and facilitating interaction with others. Full-time employees placed greater importance on managing their own health.  相似文献   
105.
The present study evaluated the hepatoprotective effect of an N-acetyl dl-methionine + choline chloride + caffeine + thiamine hydrochloride + nicotinamide + pyridoxine hydrochloride compound at doses of 0.2, 0.6 and 1.0 mL/kg of b.w., and the assessment was done by the investigation of serum-enzymatic activity, metabolic functions of the liver and histophatological changes in female Wistar rats, which were subjected to experimental intoxication with CCl4. One hundred and nineteen rats were randomly distributed into 17 groups, performing five different treatments, being evaluated seven animals per treatment in four periods: 2, 4, 6 and 8 days after CCl4-induced intoxication. Treated rats with the hepatoprotective medicine (HM) presented a significant reduction in infiltration of inflammatory cells, steatosis, necrosis and liver congestion when compared to non-treated rats (control). Beside these results, the treatment showed a positive effect on circulatory alterations in the intoxicated animals, with reduction of spleen and renal congestion, as well as, promotion of a significant improvement in ALT, AST, LDH, ALP, GGT enzymatic serum activity reduction and in recovering liver function regarding the metabolism of urea, triglycerides and glucose. These findings indicate therapeutic usefulness of the compound when administered at dose 0.6 and 1.0 mL/kg of b.w. in female Wistar rats.  相似文献   
106.
107.
Recent evidence suggests that binding of agonist to its cognate receptor initiates not only classical G protein-mediated signaling, but also beta-arrestin-dependent signaling. One such beta-arrestin-mediated pathway uses the beta(1)-adrenergic receptor (beta(1)AR) to transactivate the EGFR. To determine whether beta-adrenergic ligands that do not activate G protein signaling (i.e., beta-blockers) can stabilize the beta(1)AR in a signaling conformation, we screened 20 beta-blockers for their ability to stimulate beta-arrestin-mediated EGFR transactivation. Here we show that only alprenolol (Alp) and carvedilol (Car) induce beta(1)AR-mediated transactivation of the EGFR and downstream ERK activation. By using mutants of the beta(1)AR lacking G protein-coupled receptor kinase phosphorylation sites and siRNA directed against beta-arrestin, we show that Alp- and Car-stimulated EGFR transactivation requires beta(1)AR phosphorylation at consensus G protein-coupled receptor kinase sites and beta-arrestin recruitment to the ligand-occupied receptor. Moreover, pharmacological inhibition of Src and EGFR blocked Alp- and Car-stimulated EGFR transactivation. Our findings demonstrate that Alp and Car are ligands that not only act as classical receptor antagonists, but can also stimulate signaling pathways in a G protein-independent, beta-arrestin-dependent fashion.  相似文献   
108.
We investigated the emergence of cytomegalovirus (CMV) ganciclovir-resistance mutations in 301 high-risk solid-organ transplant (SOT) recipients after oral prophylaxis, for 100 days, with either valganciclovir or ganciclovir. For patients treated with ganciclovir, the incidence of CMV UL97 mutations was 1.9% (2/103) at the end of prophylaxis and 6.1% (2/33) for patients with suspected CMV disease up to 1 year after transplantation. No resistance mutations were detected in samples from valganciclovir-treated patients. Dual polymerase (UL54) and UL97 resistance mutations were not seen. Valganciclovir was associated with negligible risk of resistance and thus constitutes a useful alternative to ganciclovir prophylaxis for CMV in high-risk SOT recipients.  相似文献   
109.
A growing body of research evidence shows that Twelve Step Group (TSG) attendance confers a consistent moderate beneficial effect on substance use. Clinicians potentially represent a major referral pathway to TSG. This qualitative study aimed to explore staff perceptions of the barriers to Narcotics Anonymous (NA) group attendance in a population receiving drug treatment, and potential strategies to increase attendance. A cross-sectional survey of substance misuse treatment professionals was conducted between January and April 2012 in Birmingham, England. Fifty-eight members of staff working within statutory community drug treatment teams were interviewed using qualitative research methods. The overarching themes within the staff accounts are described and the importance of these themes explored. Perceived objections to core elements of the 12 step programme (religious nature of the programme, powerlessness, surrender, desire to stop using drugs) were major obstacles to recommending NA attendance. However, a perception that the client would object to any form of group process, and concerns about risk both to the client and the TSG members were also important. Increased education about TSG practices and procedures was a commonly cited strategy for increasing levels of TSG referral, and in particular ensuring that clinicians attend open meetings themselves. An increased understanding and familiarity with the process and principles of TSGs may be necessary to increase promotion of TSG within drug treatment services in line with recent national policy promoting recovery from drug use.  相似文献   
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