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   793篇
  免费   76篇
  国内免费   3篇
耳鼻咽喉   10篇
儿科学   28篇
妇产科学   13篇
基础医学   179篇
口腔科学   30篇
临床医学   62篇
内科学   182篇
皮肤病学   23篇
神经病学   67篇
特种医学   32篇
外科学   63篇
综合类   10篇
预防医学   79篇
眼科学   27篇
药学   39篇
中国医学   2篇
肿瘤学   26篇
  2023年   7篇
  2022年   10篇
  2021年   28篇
  2020年   19篇
  2019年   27篇
  2018年   36篇
  2017年   26篇
  2016年   20篇
  2015年   20篇
  2014年   24篇
  2013年   25篇
  2012年   37篇
  2011年   32篇
  2010年   23篇
  2009年   17篇
  2008年   48篇
  2007年   44篇
  2006年   40篇
  2005年   26篇
  2004年   30篇
  2003年   25篇
  2002年   26篇
  2001年   11篇
  2000年   24篇
  1999年   19篇
  1998年   16篇
  1997年   14篇
  1996年   12篇
  1995年   15篇
  1994年   7篇
  1993年   13篇
  1992年   8篇
  1991年   11篇
  1990年   6篇
  1989年   16篇
  1988年   18篇
  1987年   8篇
  1986年   6篇
  1985年   9篇
  1984年   10篇
  1983年   6篇
  1981年   5篇
  1979年   4篇
  1977年   4篇
  1976年   5篇
  1975年   5篇
  1971年   3篇
  1969年   3篇
  1968年   3篇
  1966年   4篇
排序方式: 共有872条查询结果,搜索用时 15 毫秒
91.
The purpose of this study is evaluate the efficacy and safety of medicinal products containing the original Age-Related Eye Disease group (AREDS) formulation at doses approved in Europe (EU, control group; n = 59) with a product that adds DHA, lutein, zeaxanthin, resveratrol and hydroxytyrosol to the formula (intervention group; n = 50). This was a multicenter, randomized, observer-blinded trial conducted in patients aged 50 years or older diagnosed with unilateral exudative Age related Macular Degeneration AMD. At month 12, the intervention did not have a significant differential effect on visual acuity compared with the control group, with an estimated treatment difference in Early Treatment Diabetic Retinopathy Study (ETDRS) of −1.63 (95% CI −0.83 to 4.09; p = 0.192). The intervention exhibited a significant and, in most cases, relevant effect in terms of a reduction in some inflammatory cytokines and a greater improvement in the fatty acid profile and serum lutein and zeaxantin concentration. In patients with unilateral wet AMD, the addition of lutein, zeaxanthin, resveratrol, hydroxytyrosol and DHA to the AREDS EU recommended doses in the short-term did not have a differential effect on visual acuity compared to a standard AREDS EU formula but, in addition to improving the fatty acid profile and increasing carotenoid serum levels, may provide a beneficial effect in improving the proinflammatory and proangiogenic profile of patients with AMD.  相似文献   
92.
OBJECTIVES: This paper describes and compares three innovative methods for preventing perinatal HIV transmission. Each of these strategies has been developed based on an in-depth assessment of the strengths and weaknesses of existing prevention approaches, and the needs of the populations they serve. METHODS: Florida expanded an existing outreach program to include women in jails in several high-prevalence counties. Incarcerated women were offered testing for pregnancy and HIV and linked to medical and supportive services. One Connecticut hospital sought to increase prenatal HIV testing rates by requiring HIV test results in the electronic medical records. This program is being expanded to other hospitals throughout the state. Louisiana has implemented a systematic review of perinatal data in order to identify potential programmatic enhancements. This review has led to the perinatal fast track system, designed to quickly identify HIV-infected pregnant women and connect them to care. RESULTS: Each program demonstrated improvements in indicators related to prevention of perinatal HIV transmission, such as increased utilization of prenatal care, increased prenatal testing rates, and decreases in perinatal HIV transmission. CONCLUSIONS: These case studies emphasize two key similarities among these programs: the value of collaboration between agencies providing care and services to HIV-infected and high-risk women of childbearing age, and the importance of maximizing opportunities for HIV testing and treatment. These strategies have demonstrated effectiveness in improving health outcomes and reducing perinatal HIV transmission.  相似文献   
93.
A debilitated patient with liver cirrhosis and poor haemostasis had a severe lower gastrointestinal haemorrhage. A superior mesenteric arteriogram revealed an early persistent and promiment draining vein in the ileocolic artery. Two fragments of Spongostan and silk were used to embolise the bleeding artery and the haemorhage ceased immediately. No infarction of the embolised area was observed and the bleeding was controlled.  相似文献   
94.
95.
(R/S)‐Salsolinol is a full agonist of the μ‐opioid receptor (μOR) Gi protein pathway via its (S)‐enantiomer and is functionally selective as it does not promote β‐arrestin recruitment. Compared to (S)‐salsolinol, the (R)‐enantiomer is a less potent agonist of the Gi protein pathway. We have now studied the interactions of the salsolinol enantiomers docked in the binding pocket of the μOR to determine the molecular interactions that promote enantiomeric specificity and functional selectivity of (R/S)‐salsolinol. Molecular dynamics simulations showed that (S)‐salsolinol interacted with 8 of the 11 residues of the μOR binding site, enough to stabilize the molecule. (R)‐Salsolinol showed higher mobility with fewer prevalent bonds. Hence, the methyl group bound to the (S)‐stereogenic center promoted more favorable interactions in the μOR binding site than in the (R)‐orientation. Because (S)‐salsolinol is a small molecule (179.2 Da), it did not interact with residues implicated in the binding of larger morphinan agonists that are located toward the extracellular portion of the binding pocket: W3187.35, I3227.39, and Y3267.43. Our results suggest that contact with residues which (S)‐salsolinol interacts with are enough to elicit Gi protein activation, and possibly define a minimum set required by μOR ligands to promote activation of the Gi protein pathway.  相似文献   
96.
Context: Indigofera suffruticosa Miller (Fabaceae) and I. truxillensis Kunth produce compounds, such as isatin (ISA) and indirubin (IRN), which possess antitumour properties. Their effects in mammalian cells are still not very well understood.

Objective: We evaluated the activities of ISA and/or IRN on cell viability and apoptosis in vitro, their genotoxic potentials in vitro and in vivo, and the IRN- and ISA-induced expression of ERCC1 or BAX genes.

Materials and methods: HeLa and/or CHO-K1 cell lines were tested (3 or 24?h) in the MTT, Trypan blue exclusion, acridine orange/ethidium bromide, cytokinesis-blocked micronucleus (CBMN) and comet (36, 24 and 72?h) tests after treatment with IRN (0.1 to 200?μM) or ISA (0.5 to 50?μM). Gene expression was measured by RT-qPCR in HeLa cells. Swiss albino mice received IRN (3, 4 or 24?h) by gavage (50, 100 and 150?mg/kg determined from the LD50 – 1?g/kg b.w.) and submitted to comet assay in vivo.

Results: IRN reduced the viability of CHO-K1 (24?h; 5 to 200?μM) and HeLa cells (10 to 200?μM), and was antiproliferative in the CBMN test (CHO-K1: 0.5 to 10?μM; HeLa: 5 and 10?μM). The drug did not induce apoptosis, micronucleus neither altered gene expression. IRN and ISA were genotoxic for HeLa cells (3 and 24?h) at all doses tested. IRN (100 and 150?mg/kg) also induced genotoxicity in vivo (4?h).

Conclusion: IRN and ISA have properties that make them candidates as chemotherapeutics for further pharmacological investigations.  相似文献   
97.

Rationale  

Kappa-opioid receptor (KOR) agonists produce dysphoria and psychotomimesis in humans. KORs are enriched in the prefrontal cortex and other brain regions that regulate mood and cognitive function. Dysregulation of the dynorphin/KOR system has been implicated in the pathogenesis of schizophrenia, depression, and bipolar disorder. Prepulse inhibition of the acoustic startle reflex (PPI), a sensorimotor gating process, is disrupted in many psychiatric disorders.  相似文献   
98.
99.
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