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   69792篇
  免费   5386篇
  国内免费   3833篇
耳鼻咽喉   305篇
儿科学   1299篇
妇产科学   438篇
基础医学   4785篇
口腔科学   1030篇
临床医学   10464篇
内科学   6198篇
皮肤病学   302篇
神经病学   7362篇
特种医学   4454篇
外国民族医学   2篇
外科学   14206篇
综合类   13295篇
现状与发展   3篇
一般理论   1篇
预防医学   3738篇
眼科学   900篇
药学   6325篇
  37篇
中国医学   3264篇
肿瘤学   603篇
  2024年   265篇
  2023年   1226篇
  2022年   2246篇
  2021年   3148篇
  2020年   2855篇
  2019年   2292篇
  2018年   2314篇
  2017年   2599篇
  2016年   2723篇
  2015年   2592篇
  2014年   4602篇
  2013年   5496篇
  2012年   4368篇
  2011年   4753篇
  2010年   4057篇
  2009年   3814篇
  2008年   3769篇
  2007年   3712篇
  2006年   3490篇
  2005年   3021篇
  2004年   2410篇
  2003年   2137篇
  2002年   1791篇
  2001年   1564篇
  2000年   1293篇
  1999年   1047篇
  1998年   899篇
  1997年   805篇
  1996年   666篇
  1995年   553篇
  1994年   421篇
  1993年   333篇
  1992年   278篇
  1991年   202篇
  1990年   190篇
  1989年   168篇
  1988年   124篇
  1987年   117篇
  1986年   104篇
  1985年   133篇
  1984年   84篇
  1983年   53篇
  1982年   59篇
  1981年   63篇
  1980年   56篇
  1979年   34篇
  1978年   19篇
  1977年   19篇
  1976年   20篇
  1975年   9篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
Head injury in children causes special concern in most communities. From 1989 to 1994, 2,785 children younger than 16 years old were admitted to our neurosurgical service because of head injury. Fall from a height was the major cause of head injury leading to admission in infants and children in preschool age groups, whereas traffic-related or bicycle-related accidents were more likely to be the cause of head injury for those aged 11–15 years. In all age groups there was a male preponderance. The overall mortality was 0.6%. Traffic-ralated accidents caused more severe injury and accounted for 67% of all fatalities. For patients under 6 years old, about 40% of head injuries occurred at home. Preventive measures for pediatric head injury in Hong Kong are suggested.  相似文献   
22.
电针对沙鼠急性脑缺血再灌注后神经原损伤的保护作用   总被引:9,自引:0,他引:9  
本实验利用沙鼠急性脑缺血再灌注模型,研究电针对脑缺血及再灌注各期脑电活动的影响及组织病理学的改变。结果表明:缺血10mln,脑电幅度受到严重抑制,甚至变平坦,总功率大大下降,再灌注后总功率难以恢复,在120min时仅恢复到缺血前的27.39±11.31%,以后即不再进一步恢复,电针组动物缺血10min再灌注后,脑电的恢复明显比对照组快,120min时恢复至缺血前的71.45±16.46%(P<0.01),240min时继续恢复至缺血前的75.27±18.43%。同时电针能明显减轻缺血10min后再灌注24小时的神经原缺血性损伤。结果提示:电针对急性脑缺血引起的神经原损伤具有保护作用,并能促进脑功能的恢复。  相似文献   
23.
There is a growing body of evidence that the cytokine, tumor necrosis factor-α (TNF-ga), plays an important role in the development of hepatic ischemia/reperfusion injury. We found that the immunosuppressants, cyclosporine-A (CsA), azathioprine, and FK506, have protective effects on such injury. The purpose of the present study was to elucidate mechanisms involved in these beneficial effects of the immunosuppressant, CsA, on liver injury following cold preservation and transplantation, with special reference to the suppression of TNF-α release. Rat livers were stored in Euro-Collins solution (EC) at 4°C for 6h and orthotopically transplanted. The animals allotted to two groups: group A (untreated controls) and group B (CsA pretreatment of recipients). CsA (10 mg/kg, p.o.) was given for 3 consecutive days preoperatively. CsA pretreatment of the recipients significantly improved the 2-week survival rate (0/6 for group A, 3/6 for group B;P<0.05) and this was associated with a significant decrease in serum TNF-α levels 2h posttransplantation (group A, 69.8±15.7 pg/ml; group B, 22.8±6.8; mean±SEM;n=12 each;P<0.05) and amelioration of sinusoidal endothelial injury, assessed by electron microscopy. Plasma endotoxin levels following reperfusion of the grafts were not altered by the CsA therapy. Morphologically, CsA pretreatment of the recipients did not alter activation of Kupffer cells. CsA pretreatment of the recipient aids in preventing cold preservation/reperfusion injury of the liver graft, possibly by modulating effects of TNF-α.  相似文献   
24.
A 21-year-old man was injured by a tailboard of a truck. He suffered a severe head injury with bilateral depressed skull fractures necessitating surgical decompression. On admission to the hospital the patient showed bending to pain stimuli (Glasgow Coma Score 5). Anisocoria was noticed from the beginning. Initial intracranial pressure (ICP), measured 3 hours after injury, was 30 mm Hg, and the cerebral perfusion pressure (CPP) was 70 mm Hg. During surgical elevation of the skull fracture on the right side an unexplainable rise of ICP to values of 100 mm Hg occurred, which corresponded to the mean arterial blood pressure (MAP). At the same time both pupils were dilated and fixed indicating a lack of cerebral perfusion. Due to immediate trephination of the opposite side, the ICP was lowered to values below 20 mm Hg, and sufficient cerebral perfusion (above 50 mm Hg) was regained. The patient showed a good recovery and was transferred to a rehabilitation center 5 weeks after injury.This case report emphasizes the importance of early and continuous intracranial pressure monitoring for adequate therapy in neurosurgical emergencies.  相似文献   
25.
川芎嗪对脑外伤患者血栓素、前列腺环素及颅内压的影响   总被引:6,自引:0,他引:6  
28例重度脑外伤患者分为川药嗪治疗组和一般治疗对照组,两组病人均于用药前和用药后3小时测定血浆和脑室内脑脊液(VCSF)中血栓素代谢产物(TXB_2)前列腺环素代谢产物6—酮—PGF_(la)(6KP)和颅内压。结果表明:两组治疗前血浆、VCSF中TXB_2及T/K均明显高于正常献血员对照组,川芎嗪能降低脑外伤患者血浆、VCSF中TXB_2及T/K值,对颅内压则无明显影响。提示川芎嗪能抑制脑外伤对血小板的激活、纠正循环血中TXA_2—PGI_2平衡失调,从而改善脑微循环。  相似文献   
26.
27.
A 36-year-old man was brought to the emergency department after being assaulted. A mandible series showed a nondisplaced fracture through the angle of the mandible extending through the left third molar tooth. Axial slices from a nonhelical computed tomographic (CT) examination of the head as well as a helical CT examination of the mandible failed to demonstrate the fracture. The fracture was well shown, however, on sagittal CT reformations. Although CT is generally regarded as more sensitive than plain radiography for the detection of fractures, fractures may be overlooked by CT if examination in only one plane is performed.  相似文献   
28.
29.
亚低温在治疗急性颅脑创伤中的疗效和争议   总被引:22,自引:1,他引:21  
二十世纪90年代初,国内外对亚低温脑保护的作用有了新认识。动物实验研究发现亚低温对实验性颅脑外伤具有显著的治疗保护作用。大多数前瞻性临床应用研究发现30~33℃亚低温能显著降低重型颅脑伤患者的死残率。但美国Clifton教授牵头的9个医学中心合作研究发现亚低温治疗组与对照组无统计学差异.仅能显著提高GCS 6~8分、年龄<45岁、伤后6h内达到亚低温水平的病人的治疗效果。最近一项欧州5家医院多中心前瞻性随机临床研究结果令人兴奋,他们研究证明亚低温对心跳骤停脑缺血缺氧病人有显著治疗保护作用。目前国内外有关亚低温治疗的争议焦点是亚低温治疗的指征、时间窗和时程。  相似文献   
30.
The quantitation of diffuse axonal injury provides a more objective approach to the assessment of tissue damage in head injuries. The method designed in this study takes into account the anisotropy and structural inhomogeneity of the brain, and the distribution of lesions in diffuse axonal injury. The number of counts required for the statistical analysis is inversely proportional to the square of the desired accuracy, specified as the percentage of the mean value of the axonal balloons since the true mean is unknown from the outset. The number of fields are examined using an indexed-squares graticule in 10 different areas of the brain. Silver-stained sections from the brains of head injured patients that survived longer than 12 h must be used with this method. Difficulties may arise when patients of different survival times are compared since it takes some time for the axonal balloons to develop. A correlation with the survival time can be established with the quantitative data collected. The morphometric principles and the statistical rationale on which this methodology is based are briefly presented.  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