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   1399篇
  免费   73篇
  国内免费   2篇
耳鼻咽喉   10篇
儿科学   34篇
妇产科学   52篇
基础医学   123篇
口腔科学   26篇
临床医学   129篇
内科学   306篇
皮肤病学   26篇
神经病学   66篇
特种医学   24篇
外科学   168篇
综合类   16篇
预防医学   230篇
眼科学   19篇
药学   198篇
中国医学   14篇
肿瘤学   33篇
  2024年   4篇
  2023年   14篇
  2022年   53篇
  2021年   75篇
  2020年   47篇
  2019年   68篇
  2018年   59篇
  2017年   48篇
  2016年   53篇
  2015年   54篇
  2014年   73篇
  2013年   86篇
  2012年   107篇
  2011年   115篇
  2010年   63篇
  2009年   54篇
  2008年   75篇
  2007年   56篇
  2006年   40篇
  2005年   42篇
  2004年   43篇
  2003年   42篇
  2002年   25篇
  2001年   17篇
  2000年   21篇
  1999年   22篇
  1998年   10篇
  1997年   3篇
  1995年   2篇
  1994年   3篇
  1992年   5篇
  1991年   6篇
  1990年   5篇
  1989年   2篇
  1988年   8篇
  1987年   5篇
  1986年   9篇
  1985年   3篇
  1984年   4篇
  1983年   2篇
  1981年   2篇
  1979年   4篇
  1978年   2篇
  1977年   3篇
  1976年   5篇
  1975年   7篇
  1974年   6篇
  1973年   7篇
  1972年   3篇
  1966年   2篇
排序方式: 共有1474条查询结果,搜索用时 10 毫秒
91.
Homology modeling in combination with molecular docking studies has been applied to predict the binding modes of the Hepatitis C virus (HCV) NS5B-3a inhibitors within the pocket of NS5B polymerase of HCV genotype 3a. Structure modeling and docking using Genetic Optimization for Ligand Docking (GOLD) were carried out to understand the ligand binding properties of NS5B-3a and to identify a potent inhibitor against it. The three-dimensional homology model of Pakistani strain is not available and was built based on the HCV-J4 NS5B polymerase structure. Compound 1 possessing high GOLD fitness score of 62.17 with IC50 value of 0.04 μM was selected as the potent inhibitor. The docking analysis depicted that hydrogen bonding, ionic and hydrophobic interactions contributed significantly for its ligand binding and the amino acid residues Arg442 and His403 seemed to be the anchor residues for receptor recognition. For developing a connection between the experimental bioactivities and GOLD fitness scores, a squared correlation coefficient was calculated and found as acceptable with the value of r 2 = 0.67. These findings may act as potent lead in designing effective NS5B-3a inhibitors.  相似文献   
92.
93.
BACKGROUND: It is not known whether total circulating lipid hydroperoxides are increased in insulin-resistant individuals and whether this correlates with depletion of liposoluble antioxidant vitamins that are consumed during lipid peroxidation. OBJECTIVE: The goal of this study was to define the relation between resistance to insulin-mediated glucose disposal and plasma concentrations of lipid hydroperoxides and liposoluble antioxidant vitamins in healthy volunteers. DESIGN: Insulin-mediated glucose disposal was determined in 36 healthy, nondiabetic volunteers by measuring their steady-state plasma insulin (SSPI) and glucose (SSPG) concentrations in response to a 180-min constant infusion of octreotide, insulin, and glucose. In addition, fasting plasma concentrations of lipid hydroperoxides and liposoluble antioxidant vitamins were determined by using the FOX 2 assay and liquid chromatography. RESULTS: Statistically significant direct relations were observed between SSPG and mean arterial blood pressure (r = 0.44, P: = 0.008) and plasma lipid hydroperoxide concentrations (r = 0.42, P: = 0.01), whereas significant inverse correlations were found between SSPG and alpha-carotene (r = -0.58, P: = 0.0002), beta-carotene (r = -0.49, P: = 0.004), lutein (r = -0.35, P: = 0.04), alpha-tocopherol (r = -0. 36, P: = 0.04), and delta-tocopherol (r = -0.45, P: = 0.007). CONCLUSIONS: Variations in insulin-mediated glucose disposal in healthy individuals are significantly related to plasma concentrations of lipid hydroperoxides and liposoluble antioxidant vitamins. These findings suggest that total plasma lipid peroxidation is increased in insulin-resistant individuals at an early, preclinical stage, ie, well before the development of glucose intolerance and type 2 diabetes.  相似文献   
94.
95.
First generation Leishmania vaccines consisting of whole killed parasites with or without adjuvants have reached phase 3 trial and failed to show enough efficacy mainly due to the lack of an appropriate adjuvant. In this study, the nuclease-resistant phosphorothioate CpG oligodeoxynucleotides (PS CpG) or nuclease-sensitive phosphodiester CpG ODNs (PO CpG) were used as adjuvants to enhance immunogenicity and rate of protection against leishmaniasis. Due to the susceptibility of PO CpG to nuclease degradation, an efficient liposomal delivery system was developed to protect them from degradation. 1, 2-dioleoyl-3-trimethylammonium-propane (DOTAP) as a cationic lipid was used because of its unique adjuvanticity and electrostatic interaction with negatively charged CpG ODNs. To evaluate the role of liposomal formulation in protection rate and enhanced immune response, BALB/c mice were immunized subcutaneously with liposomal soluble Leishmania antigens (SLA) co-incorporated with PO CpG (Lip-SLA-PO CpG), Lip-SLA-PS CpG, SLA+PO CpG, SLA+PS CpG, SLA or buffer. As criteria for protection, footpad swelling at the site of challenge, parasite loads, the levels of IFN-γ and IL-4, and the IgG subtypes were evaluated. The groups of mice receiving Lip-SLA-PO CpG or Lip-SLA-PS CpG showed a high protection rate compared with the control groups. In addition, there was no significant difference in immune response generation between mice immunized with PS CpG and the group receiving PO CpG when incorporated into the liposomes. The results suggested that liposomal form of PO CpG might be used instead of PS CpG in future vaccine formulations as an efficient adjuvant.  相似文献   
96.
97.
98.
Lower gastrointestinal bleeding in elderly patients   总被引:4,自引:0,他引:4  
Lower gastrointestinal bleeding (LGIB) is one of the common medical emergencies that can become life-threatening in elderly patients. Increased prevalence of cerebrovascular and cardiovascular diseases, malignancy, polypharmacy, and the use of nonsteroidal anti-inflammatory drugs in elderly patients adversely affects the outcome of LGIB. Diverticular bleeding, vascular ectasia, polyps and hemorrhoids are among the common causes of LGIB in the elderly. In a majority of cases, LGIB stops spontaneously with resuscitation and supportive therapy. In those elderly patients in whom LGIB continues, benefits of endoscopic, angiographic, or surgical intervention should not be withheld because of age alone. However, the timing of tests and the type of intervention should be custom tailored for frail elderly patients. Such a decision should depend upon functional status, its impact on outcome, and the consent process.  相似文献   
99.
Increase of distribution of environmental contaminants such as heavy metals have been caused the knowledge of the safety and hygiene of food is very important, especially eggs, because of its role in the daily diet. There are very few studies about the investigation of the heavy metal contents in egg-white. In this study, six heavy metals include Aluminium (Al), Arsenic (As), Lead (Pb), Cadmium (Cd), Mercury (Hg), Antimony (Sb) in egg-white from 32 industrial poultry farms were investigated, by ICP-OES. All the samples were collected in all area of Markazi Province, Iran in autumn 2013. The mean concentrations of heavy metals in egg-white as follows: 0.119 for Al, 0.785 for As, 0.750 for Pb, 0.249 for Cd, 0.270 for Hg and 0.186?mg/kg for Sb. Also, the concentration of the some heavy metals were higher than maximum allowable concentration that probably it is associated to use pesticides and activities of industrial factories around the poultry farms.  相似文献   
100.
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