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   2744767篇
  免费   199149篇
  国内免费   7075篇
耳鼻咽喉   38023篇
儿科学   83691篇
妇产科学   73140篇
基础医学   404192篇
口腔科学   75746篇
临床医学   245570篇
内科学   534023篇
皮肤病学   61326篇
神经病学   214172篇
特种医学   104300篇
外国民族医学   559篇
外科学   414698篇
综合类   57479篇
现状与发展   18篇
一般理论   953篇
预防医学   202601篇
眼科学   64821篇
药学   209639篇
  11篇
中国医学   7878篇
肿瘤学   158151篇
  2021年   24833篇
  2019年   24259篇
  2018年   33623篇
  2017年   25332篇
  2016年   28650篇
  2015年   33201篇
  2014年   45854篇
  2013年   66074篇
  2012年   91926篇
  2011年   96572篇
  2010年   57455篇
  2009年   53681篇
  2008年   88541篇
  2007年   94012篇
  2006年   93957篇
  2005年   90585篇
  2004年   85983篇
  2003年   82367篇
  2002年   79242篇
  2001年   130480篇
  2000年   133514篇
  1999年   111919篇
  1998年   31770篇
  1997年   27512篇
  1996年   27328篇
  1995年   25675篇
  1994年   23563篇
  1993年   22106篇
  1992年   84591篇
  1991年   81920篇
  1990年   79680篇
  1989年   76961篇
  1988年   70586篇
  1987年   69027篇
  1986年   64407篇
  1985年   61584篇
  1984年   45055篇
  1983年   38071篇
  1982年   22224篇
  1979年   40490篇
  1978年   28491篇
  1977年   23870篇
  1976年   22366篇
  1975年   24151篇
  1974年   28877篇
  1973年   27352篇
  1972年   25721篇
  1971年   24458篇
  1970年   22516篇
  1969年   21580篇
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
81.
82.
Dosage form is a mean used for the delivery of drug to a living body. In order to get the desired effect the drug should be delivered to its site of action at such rate and concentration to achieve the maximum therapeutic effect and minimum adverse effect. Since oral route is still widely accepted route but having a common drawback of difficulty in swallowing of tablets and capsules. Therefore a lot of research has been done on novel drug delivery systems. This review is about oral dispersible tablets a novel approach in drug delivery systems that are now a day''s more focused in formulation world, and laid a new path that, helped the patients to build their compliance level with the therapy, also reduced the cost and ease the administration especially in case of pediatrics and geriatrics. Quick absorption, rapid onset of action and reduction in drug loss properties are the basic advantages of this dosage form.  相似文献   
83.
Potential for widespread transmission of HIV/AIDS among American Indian (AI) adolescents exists, yet no evidence-based interventions (EBIs) have been adapted and evaluated with this population. Intensive psychoeducation may improve knowledge and decision-making which could potentially translate to reductions in HIV risk behaviors. A peer group randomized controlled comparison of an adapted EBI vs. control was delivered over an eight-day summer basketball camp in one reservation-based tribal community to adolescents ages 13–19. Outcome data were gathered immediately post-camp and at 6 and 12 months follow-up. Self-selected peer groups were randomized to intervention (n = 138) or control (n = 129) conditions for a total sample of 267 participants (56.2% female), mean age 15.1 years (SD = 1.7). Intervention participants had better condom use self-efficacy post-camp (Adjusted Mean Difference [AMD] = ?0.75, p < 0.005) and at 6 (AMD = ?0.44, p < 0.005) and 12 months (AMD = ?0.23, p < 0.05) follow-up. Intervention participants also had higher HIV prevention and transmission knowledge (post-camp: AMD = 0.07, p < 0.01; 6 months: AMD = 0.06, p < 0.01) were more likely to believe condoms prevent sexually transmitted infections (post-camp: RR = 1.41, p < 0.005; 6 months: RR = 1.34, p < 0.05), to talk with an adult about HIV/AIDS (post-camp: RR=1.78, p < 0.005; 6 months: RR = 1.14, p < 0.005), had higher partner negotiation efficacy related to substance use during sex (post-camp: AMD = 0.37, p < 0.01), and were more likely to intend to use a condom (post-camp: RR = 1.39, p < 0.01). The adapted intervention had short- and medium-term impacts on AI adolescent risk for HIV/AIDS, but attenuated at 12 months. Intervention delivery through a community-based camp is feasible and acceptable with strong retention. Additional study is needed to evaluate the adapted intervention's impact on sexual risk behaviors and if booster sessions and parent involvement translate to long-term impacts.  相似文献   
84.
85.
86.
Bipolar disorder (BD) is a common psychiatric mood disorder affecting more than 1-2% of the general population of different European countries. Unfortunately, there is no objective laboratory-based test to aid BD diagnosis or monitor its progression, and little is known about the molecular basis of BD. Here, we performed a comparative proteomic study to identify differentially expressed plasma proteins in various BD mood states (depressed BD, manic BD, and euthymic BD) relative to healthy controls. A total of 10 euthymic BD, 20 depressed BD, 15 manic BD, and 20 demographically matched healthy control subjects were recruited. Seven high-abundance proteins were immunodepleted in plasma samples from the 4 experimental groups, which were then subjected to proteome-wide expression profiling by two-dimensional electrophoresis and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight tandem mass spectrometry. Proteomic results were validated by immunoblotting and bioinformatically analyzed using MetaCore. From a total of 32 proteins identified with 1.5-fold changes in expression compared with healthy controls, 16 proteins were perturbed in BD independent of mood state, while 16 proteins were specifically associated with particular BD mood states. Two mood-independent differential proteins, apolipoprotein (Apo) A1 and Apo L1, suggest that BD pathophysiology may be associated with early perturbations in lipid metabolism. Moreover, down-regulation of one mood-dependent protein, carbonic anhydrase 1 (CA-1), suggests it may be involved in the pathophysiology of depressive episodes in BD. Thus, BD pathophysiology may be associated with early perturbations in lipid metabolism that are independent of mood state, while CA-1 may be involved in the pathophysiology of depressive episodes.  相似文献   
87.
88.
89.
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   
90.
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