首页 | 官方网站   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   174217篇
  免费   895篇
医药卫生   175112篇
  2018年   21915篇
  2017年   17356篇
  2016年   19500篇
  2015年   877篇
  2014年   762篇
  2013年   713篇
  2012年   6867篇
  2011年   20906篇
  2010年   18757篇
  2009年   11464篇
  2008年   19406篇
  2007年   21603篇
  2006年   451篇
  2005年   2077篇
  2004年   3287篇
  2003年   4260篇
  2002年   2413篇
  2001年   254篇
  2000年   394篇
  1999年   149篇
  1998年   190篇
  1997年   195篇
  1996年   83篇
  1995年   95篇
  1994年   92篇
  1993年   55篇
  1992年   34篇
  1991年   81篇
  1990年   120篇
  1989年   73篇
  1988年   50篇
  1987年   37篇
  1986年   21篇
  1985年   28篇
  1984年   18篇
  1983年   20篇
  1982年   24篇
  1980年   39篇
  1974年   19篇
  1970年   19篇
  1969年   20篇
  1968年   17篇
  1939年   20篇
  1938年   60篇
  1937年   25篇
  1935年   22篇
  1934年   30篇
  1933年   14篇
  1932年   56篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
The interaction between MDMA and Nicotine affects multiple brain centres and neurotransmitter systems (serotonin, dopamine and glutamate) involved in motor coordination and cognition. In this study, we have elucidated the effect of prolonged (10 days) MDMA, Nicotine and a combined Nicotine-MDMA treatment on motor-cognitive neural functions. In addition, we have shown the correlation between the observed behavioural change and neural structural changes induced by these treatments in BALB/c mice. We observed that MDMA (2 mg/Kg body weight; subcutaneous) induced a decline in motor function, while Nicotine (2 mg/Kg body weight; subcutaneous) improved motor function in male periadolescent mice. In combined treatment, Nicotine reduced the motor function decline observed in MDMA treatment, thus no significant change in motor function for the combined treatment versus the control. Nicotine or MDMA treatment reduced memory function and altered hippocampal structure. Similarly, a combined Nicotine-MDMA treatment reduced memory function when compared with the control. Ultimately, the metabolic and structural changes in these neural systems were seen to vary for the various forms of treatment. It is noteworthy to mention that a combined treatment increased the rate of lipid peroxidation in brain tissue.  相似文献   
992.
993.
994.
995.
996.
Ophthalmic involvement is the most debilitating complication of Behcet’s disease (BD). The aim of the current study is to report on the efficacy and safety of a long-term use of interferon alpha-2a (IFNα-2a) in the treatment of refractory ophthalmic BD in the Azari population of Iran. We retrospectively analyzed the clinical data of 12 patients with ophthalmic BD who were under IFNα-2a therapy. All these patients had previously been treated unsuccessfully with corticosteroid and at least one conventional immunosuppressive drug. IFNα-2a was administered at a daily dose of 6 million IU (MIU). After controlling the symptoms, a dose of 6 MIU three times per week was applied for 8–12 weeks, and then, a dose of 3 MIU was administered three times per week as a subcutaneous injection. Visual acuity and total inflammatory activity index (TIAI) were used in order to assess the response to the treatment. Response to the treatment and complete eye remission were obtained in 10 (83.3 %) and 7 (58.3 %) patients, irrespectively. Improvement or stabilization of visual acuity was observed in 18 (81.8 %) out of 22 eyes. After a mean period of 29.6 months, the use of IFNa-2a was discontinued in eight (66.7 %) patients. Unaltered vision for 2 years after IFNa-2a discontinuation happened in eight (100 %) patients. IFNa-2a is probably effective and safe in the treatment of refractory sight-threatening ophthalmic BD in the Azari population of Iran.  相似文献   
997.
The aim of this study is to verify the prevalence of risk factors for transient osteoporosis (TO) in a cohort of patients selected by strict diagnostic criteria. Retrospective observational cohort study on outpatients’ data. Inclusion criteria were: (1) acute onset of pain at a lower limb joint exacerbated by weight bearing; (2) no history of trauma, tumors, rheumatic diseases, or infection; (3) presence bone marrow edema on MRI in a weight bearing joint without signs of intraarticular lesions; (4) no hyperesthesia and/or allodynia and/or sweeting changes. The following risk factors were search for in all patients: (1) previous episode of TO; (2) disorders of bone metabolism; (3) cigarette smoke; (4) sudden lower limb overuse; (5) presence of osteoporosis/osteopenia. Twenty-three patients (8 females, 15 males, mean age 48.4 years) fulfilled the inclusion criteria. An average of 1.96 risk factors for TO was present in the cohort. The most frequent risk factor was overuse (in 15 patients, 65.2 %) and the second risk factor was bone metabolism disorders (in 10 patients, 43.5 %). Seven patients (30.4 %) were heavy smokers (more than 20 cigarettes per day) and seven patients showed a previous episode of TO. Six patients (26.1 % of the overall cohort but 60 % of those investigated with DEXA) resulted osteoporotic or osteopenic. Our results suggest there are risk factors that must be investigated in these patients. The presence of these risk factors might support the thesis that their disorder is tied to a decoupling between microdamage accumulation and self-reparative ability of bone tissue. The identification of risk factors with a precise diagnostic pathway can accelerate the diagnostic process and reduce recurrences.  相似文献   
998.
999.
1000.
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-23

京公网安备 11010802026262号