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   1261篇
  免费   93篇
  国内免费   4篇
耳鼻咽喉   4篇
儿科学   85篇
妇产科学   23篇
基础医学   158篇
口腔科学   18篇
临床医学   167篇
内科学   286篇
皮肤病学   21篇
神经病学   88篇
特种医学   27篇
外科学   149篇
综合类   48篇
预防医学   37篇
眼科学   10篇
药学   59篇
中国医学   10篇
肿瘤学   168篇
  2023年   21篇
  2022年   18篇
  2021年   46篇
  2020年   23篇
  2019年   35篇
  2018年   44篇
  2017年   36篇
  2016年   33篇
  2015年   42篇
  2014年   51篇
  2013年   60篇
  2012年   94篇
  2011年   96篇
  2010年   60篇
  2009年   45篇
  2008年   63篇
  2007年   58篇
  2006年   67篇
  2005年   69篇
  2004年   51篇
  2003年   41篇
  2002年   39篇
  2001年   21篇
  2000年   29篇
  1999年   32篇
  1998年   16篇
  1997年   6篇
  1996年   7篇
  1995年   5篇
  1994年   7篇
  1993年   5篇
  1992年   11篇
  1991年   10篇
  1990年   9篇
  1989年   14篇
  1988年   13篇
  1987年   6篇
  1986年   6篇
  1985年   5篇
  1983年   5篇
  1982年   5篇
  1979年   11篇
  1977年   5篇
  1975年   3篇
  1974年   9篇
  1971年   2篇
  1970年   2篇
  1968年   3篇
  1967年   3篇
  1966年   3篇
排序方式: 共有1358条查询结果,搜索用时 15 毫秒
1.
2.
3.
The methanolic fraction of P. indica root extract was found to possess significant antiulcer activity in different experimental animal models. In preventive antiulcer tests, significant protective actions in acetylsalicylic acid, serotonin and indomethacin-induced gastric lesions were observed in experimental rats. The extract also afforded significant protection to chemically-induced duodenal lesion in guineapigs. Significant enhancement of healing process in acetic acid-induced chronic gastric lesions were also observed in the extract-treated animals.  相似文献   
4.
Summary   Epileptic psychoses reflect a fundamental disruption in the fidelity of mind and occur during seizure freedom or during or after seizures. The psychotic symptoms in epilepsy share some qualities with schizophrenic psychosis, such as positive symptoms of paranoid delusions and hallucinations. Psychotic syndromes in epilepsy are most common but not exclusively associated with temporal lobe epilepsy. De Novo psychosis following epilepsy surgery is rare. Forced normalization—psychosis associated with dramatic reduction of epileptiform activity or seizures is described in small series only. Ictal and postictal psychosis can be prevented with seizure control, but postictal and chronic interictal psychoses require multidisciplinary and psychopharmacologic management.  相似文献   
5.
The goal was to determine the age-related changes in accommodative movements of the lens and ciliary body in rhesus monkeys. Varying levels of accommodation were stimulated via the Edinger-Westphal (E-W) nucleus in 26 rhesus monkeys, aged 6–27 years, and the refractive changes were measured by coincidence refractometry. Centripetal ciliary process (CP) and lens movements were measured by computerized image analysis of goniovideographic images. Ultrasound biomicroscopy (UBM) at 50 MHz was used to visualize and measure accommodative forward movements of the ciliary body in relation to age, accommodative amplitude, and centripetal CP and lens movements. At ~3 diopters of accommodation, the amount of centripetal lens movement required did not significantly change with age (p = 0.10; n = 18 monkeys); however, the amount of centripetal CP movement required significantly increased with age (p = 0.01; n = 18 monkeys), while the amount of forward ciliary body movement significantly decreased with age (p = 0.007; n = 11 monkeys). In the middle-aged animals (12–16.5 years), a greater amount of centripetal CP movement was required to induce a given level of lens movement and thereby a given level of accommodation (p = 0.01), compared to the young animals (6–10 yrs). Collectively, the data suggests that, with age, the accommodative system may be attempting to compensate for the loss of forward ciliary body movement by increasing the amount of centripetal CP movement. This, in turn, would allow enough zonular relaxation to achieve the magnitude of centripetal lens movement necessary for a given amplitude of accommodation.  相似文献   
6.
Oxygen free radicals (OFR) are implicated in thepathogenesis of stress, chemically induced gastriclesions, and gastrointestinal injury. Theconcentration-dependent scavenging abilities of bismuthsubsalicylate (SBS), colloidal bismuth subcitrate (CBS), andselected OFR scavengers, including superoxide dismutase(SOD), catalase, mannitol, and allopurinol were examinedagainst biochemically or chemically generated superoxide anion, hydroxyl radical, andhypochlorite radical plus hypochlorous acid based on achemiluminescence assay. Furthermore, both gastric (GM)and intestinal mucosa (IM) were individually exposed in vitro to these free radical generatingsystems, and the concentration-dependent protectiveabilities of SBS and CBS against lipid peroxidation (LP)were compared with selected OFR scavengers. In addition, 24-hr fasted rats were orally treated with thenecrotizing agents 0.6 M HCl, 0.2 M NaOH, 80% ethanol,and aspirin (200 mg/kg). The extent of tissue injury inthe GM and IM was determined by assessing LP, DNA fragmentation, and membrane microviscosity.Dose- and time-dependent in vivo protective abilities ofCBS (100 mg/kg) and SBS (15 mg/kg) were also assessed.Following incubations with superoxide anion and hydroxyl radical generating systems in thepresence of 125 mg SBS/liter, approximately 47% and 61%inhibitions were observed in the chemiluminescenceresponse, respectively, while 48% and 46% inhibitions were observed with 125 mg CBS/liter. SBS andCBS exerted similar abilities towards hypochloriteradical plus hypochlorous acid. Approx. 3.1- and3.7-fold increases in LP were observed in the GM and IMof rats following oral administration of 0.6 MHCl. Pretreatment of the rats with SBS and CBS decreased0.6 M HCl-induced LP in the GM by approx. 39% and 27%,respectively, with similar decreases in LP in the IM. SBS exhibited better protectiveabilities towards 0.6 M HCl and 0.2 m NaOH-induced GMand IM injury as compared to CBS. SBS and CBS providedsimilar protection towards 80% ethanol-induced gastric injury, while CBS exerted a superior protectiveability towards aspirin-induced gastric injury. Theresults demonstrate that both SBS and CBS can scavengereactive oxygen species and prevent tissue damage produced by OFR.  相似文献   
7.
8.
9.
Academic medical centers face barriers to training physicians in systems- and practice-based learning competencies needed to function in the changing health care environment. To address these problems, at the University of Virginia School of Medicine the authors developed the Clinical Health Economics System Simulation (CHESS), a computerized team-based quasi-competitive simulator to teach the principles and practical application of health economics. CHESS simulates treatment costs to patients and society as well as physician reimbursement. It is scenario based with residents grouped into three teams, each team playing CHESS using differing (fee-for-service or capitated) reimbursement models. Teams view scenarios and select from two or three treatment options that are medically justifiable yet have different potential cost implications. CHESS displays physician reimbursement and patient and societal costs for each scenario as well as costs and income summarized across all scenarios extrapolated to a physician's entire patient panel. The learners are asked to explain these findings and may change treatment options and other variables such as panel size and case mix to conduct sensitivity analyses in real time. Evaluations completed in 2003 by 68 (94%) CHESS resident and faculty participants at 19 U.S. residency programs preferred CHESS to a traditional lecture-and-discussion format to learn about medical decision making, physician reimbursement, patient costs, and societal costs. Ninety-eight percent reported increased knowledge of health economics after viewing the simulation. CHESS demonstrates the potential of computer simulation to teach health economics and other key elements of practice- and systems-based competencies.  相似文献   
10.
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