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   3332篇
  免费   232篇
  国内免费   18篇
耳鼻咽喉   12篇
儿科学   84篇
妇产科学   55篇
基础医学   388篇
口腔科学   175篇
临床医学   321篇
内科学   633篇
皮肤病学   126篇
神经病学   263篇
特种医学   90篇
外科学   443篇
综合类   60篇
预防医学   253篇
眼科学   202篇
药学   302篇
中国医学   31篇
肿瘤学   144篇
  2024年   7篇
  2023年   53篇
  2022年   118篇
  2021年   229篇
  2020年   128篇
  2019年   184篇
  2018年   200篇
  2017年   148篇
  2016年   161篇
  2015年   140篇
  2014年   190篇
  2013年   226篇
  2012年   350篇
  2011年   324篇
  2010年   175篇
  2009年   144篇
  2008年   172篇
  2007年   192篇
  2006年   132篇
  2005年   114篇
  2004年   69篇
  2003年   52篇
  2002年   41篇
  2001年   5篇
  2000年   6篇
  1999年   5篇
  1998年   4篇
  1997年   2篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1990年   1篇
  1989年   3篇
  1988年   2篇
  1987年   2篇
排序方式: 共有3582条查询结果,搜索用时 15 毫秒
971.
Cardiovascular complications are the major cause of morbidity and mortality in patients with diabetes mellitus (DM). Strategies that interrupt the renin-angiotensin system have been shown to reduce the ensuing threatening risk factors. The present study was carried out to investigate the effect of subchronic administration of enalapril on the aortic reactivity of streptozotocin (STZ)-diabetic rats. For this purpose, STZ-diabetic rats received enalapril (10 and 20 mg/kg ip) daily for 2 months. Contractile responses to phenylephrine (PE) and relaxation responses to acetylcholine (Ach) and isosorbide dinitrate (ISD) were obtained from aortic rings. Concentration-response curves from enalapril-treated diabetic (ED) rats to PE were attenuated as compared to vehicle-treated diabetics (VD), especially at a dose of 20 mg/kg for enalapril. In addition, endothelium-dependent relaxation responses induced by Ach was significantly higher in ED rats as compared to diabetic ones. The endothelium-independent relaxation responses for ISD were also found not to be significantly different among the groups. Therefore, subchronic treatment of diabetic rats with enalapril in a dose-dependent manner could prevent the functional changes in vascular reactivity in diabetic rats.  相似文献   
972.
973.
Movement disorders associated with multiple sclerosis (MS) are uncommon, except for tremor. We report two patients with relapsing-remitting MS, who developed either dystonia or chorea during clinical exacerbation of their MS. The movement disorders resolved during treatment with adrenocorticotropin hormone (ACTH). Acute exacerbations of MS may be associated with transient movement disorders, which are responsive to ACTH.  相似文献   
974.
Extracts obtained from the leaves of Lavandula angustifolia Mill. (Lamiaceae) are used in Iranian folk medicine as remedies for the treatment of various inflammatory diseases. For evaluation of its probable analgesic and anti-inflammatory effects, hydroalcoholic extract, polyphenolic fraction and essential oil of the leaves of the herb were prepared and their analgesic effects were studied in mice using formalin and acetic acid-induced writhing tests. Carrageenan test in rats was used for assessment of anti-inflammatory activity of above-mentioned fractions. Results showed that while the hydroalcoholic extract (400-1600 mg/kg, p.o.) inhibited only the second phase of formalin test, the polyphenolic fraction (800 and 1600 mg/kg, p.o.) and essential oil (100 and 200 mg/kg, p.o.) suppressed both phases. In acetic acid-induced writhing test, polyphenolic fraction (400 and 800 mg/kg, p.o.) and essential oil (100 and 200 mg/kg, p.o.) reduced the number of abdominal constrictions. Essential oil at a dose of 200mg/kg also inhibited carrageenan-induced paw edema. Results of the present study confirm the traditional use of Lavandula angustifolia for the treatment of painful and inflammatory conditions and calls for further investigations to determine the active chemical constituent(s).  相似文献   
975.
We previously demonstrated that interleukin-1 (IL-1) and tumor necrosis factor (TNF) activities only partially account for calvarial bone resorption induced by local application of lipopolysaccharide (LPS) in mice. The present study was undertaken to determine the role and relative contribution of IL-11 and prostaglandin(s) (PG[s]) in LPS-induced bone resorption in vivo. A one-time dose of LPS was injected into the subcutaneous tissue overlying calvaria of mice lacking IL-1 receptor type I (IL-1RI(-/-)), mice lacking TNF receptor p55 and IL-1RI (TNFRp55(-/-)-IL-1RI(-/-)), and wild-type mice. Mice were then treated with injections of anti-IL-11 monoclonal antibody (MAb), indomethacin, or phosphate-buffered saline (PBS) and sacrificed 5 days later. Histological sections stained for tartrate-resistant acid phosphatase (TRAP) were quantified by histomorphometric analysis. At low doses of LPS (100 microg/mouse), the percentages of bone surface covered by osteoclasts were found to be similar in three strains of mice. The increase was reduced by 37% with anti-IL-11 MAb and by 46% with indomethacin. At higher doses of LPS (500 microg/mouse), we found an eightfold increase in these percentages in wild-type mice and a fivefold increase in these percentages in IL-1RI(-/-) and TNFRp55(-/-)-IL-1RI(-/-) mice after normalizing with the value from the saline-PBS control group in the same strain of mice. The increase was reduced by 55 and 69% in wild-type mice and by 50 and 57% in IL-1RI(-/-) and TNFRp55(-/-)-IL-1RI(-/-) mice treated with anti-IL-11 MAb or indomethacin, respectively. Our findings suggest that in vivo, at low doses of LPS (100 microg/mouse), LPS-induced bone resorption is mediated by IL-11 and PGs, while at high doses of LPS (500 microg/mouse), it is mediated by IL-11, PGs, IL-1, and TNF signaling. IL-11 and PGs mediate LPS-induced bone resorption by enhancing osteoclastogenesis independently of the IL-1 or TNF signaling.  相似文献   
976.

Background  

The current debate about medical futility is mostly driven by theoretical and personal perspectives and there is a lack of empirical data to document experts and public attitudes towards medical futility.  相似文献   
977.
Previous studies in our laboratory using a combination of polymerase chain reaction and restriction fragment length polymorphism have identified at least five different genotypes of infectious laryngotracheitis virus (ILTV). However, the virulence of these classes of ILTV was not investigated. In this study, five groups (16 birds each) of 3-week-old specific pathogen free chickens were inoculated via the intratracheal route with 10(3) median embryo infected dose of five different strains of ILTV. Three further groups of chickens were inoculated similarly with the vaccine strains SA2 and A20 or with sterile phosphate-buffered saline (PBS) for comparison. Four days post-inoculation, clinical signs were monitored for scoring, and eight chickens from each group were subsequently euthanized, weighed and subjected to pathological and histopathological examinations. The remaining birds were monitored for clinical signs and mortality until 21 days post-inoculation. All groups inoculated with ILTV strains showed moderate to severe clinical signs 4 days after inoculation. The strain Q1-96 caused only minimal breathing symptoms with a median score that was not significantly different to that of the group inoculated with PBS, but was significantly different to those of the groups inoculated with other ILTV strains. The strain Q1-96 caused severe photophobia and conjunctivitis with a median score that was significantly higher than those of all other groups except for the group inoculated with the strain N3-04. All ILTV strains caused a significant reduction in weight gain when compared with the group inoculated with PBS. The strain Q1-96 caused an average weigh loss of 14% that was significantly higher than those of other ILTV strains. The strains S2-04 and Q1-96 induced only minor microscopic tracheal lesions while all the other ILTV strains, including the vaccine strains A20 and SA2, induced moderate to severe microscopic tracheal lesions. Median scores for microscopic tracheal lesions were well correlated with the number of viral genomes detected in trachea. The results revealed that there is considerable variation among ILTV strains in their tropism for trachea or conjunctiva. In addition it was revealed that ILTV strains with high affinity for conjunctiva can severely affect weigh gain. The ILTV numbers and microscopic lesions in trachea were not found to be reliable indicators of virulence since they are not necessarily correlated with mortality rate in ILT.  相似文献   
978.
979.

Objective  

A fatality in one multiple sclerosis (MS) patient due to acute idiopathic thrombocytopenic purpura (ITP) and a near fatality in another stimulated our interest in platelet function abnormalities in MS. Previously, we presented evidence of platelet activation in a small cohort of treatment-naive MS patients.  相似文献   
980.
In the current study, we aimed to investigate the effect of saffron supplementation on glycemic status, lipid profile, atherogenic indices, and oxidative status in patients with type-2 diabetes (T2DM). In a randomized, double-blind controlled trial, 70 patients were randomly allocated into two groups (n = 35, each) and received 100 mg/day of saffron or placebo for eight weeks. Dietary intake, weight, body mass index (BMI), waist and hip circumferences (WC and HC), waist to hip ratio (WHR), fasting blood sugar (FBS), hemoglobin A1c (HbA1c), insulin, and Homeostatic model assessment for insulin resistance (HOMA-IR), lipid profile, atherogenic indices, oxidative status, and liver enzymes were determined before and after the intervention. At the end of the eighth week, saffron intervention could significantly reduce FBS (7.57%), lipid profile (except high-density lipoprotein cholesterol [HDL-C]), atherogenic indices, and liver enzymes (p < .05). Moreover, saffron could improve oxidative status (nitric oxide [NO] and malondialdehyde [MDA] reduced by 26.29% and 16.35%, respectively). Catalase (CAT) concentration remained unchanged. Saffron supplementation may alleviate T2DM by improving glycemic status, lipid profile, liver enzymes, and oxidative status. Further investigation is necessary to assess possible side effects and confirm the positive effect of saffron as a complementary therapy in clinical recommendations for T2DM.  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