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   25998篇
  免费   8344篇
  国内免费   166篇
耳鼻咽喉   229篇
儿科学   586篇
妇产科学   505篇
基础医学   5073篇
口腔科学   1046篇
临床医学   3949篇
内科学   6492篇
皮肤病学   573篇
神经病学   1998篇
特种医学   1796篇
外科学   6025篇
综合类   289篇
一般理论   11篇
预防医学   2925篇
眼科学   426篇
药学   1350篇
  1篇
中国医学   12篇
肿瘤学   1222篇
  2021年   384篇
  2020年   278篇
  2018年   372篇
  2017年   386篇
  2016年   559篇
  2015年   886篇
  2014年   1501篇
  2013年   2139篇
  2012年   712篇
  2011年   617篇
  2010年   1206篇
  2009年   1310篇
  2008年   560篇
  2007年   383篇
  2006年   503篇
  2005年   417篇
  2004年   369篇
  2003年   311篇
  2002年   336篇
  2001年   485篇
  2000年   386篇
  1999年   587篇
  1998年   802篇
  1997年   768篇
  1996年   818篇
  1995年   784篇
  1994年   662篇
  1993年   608篇
  1992年   603篇
  1991年   579篇
  1990年   522篇
  1989年   616篇
  1988年   633篇
  1987年   625篇
  1986年   578篇
  1985年   623篇
  1984年   562篇
  1983年   541篇
  1982年   590篇
  1981年   564篇
  1980年   536篇
  1979年   526篇
  1978年   511篇
  1977年   518篇
  1976年   441篇
  1975年   402篇
  1974年   367篇
  1973年   344篇
  1972年   348篇
  1971年   313篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Summary The rectus abdommis myocutaneous flap, based on the deep inferior epigastric vessels, is an excellent flap for reconstructing large wounds of the groin and perineum. However, wound infection in the donor site is a potential complication, even with thorough preparation of the recipient site. We present one such case in a diabetic patient who developed a necrotizing fasciitis and evisceration following transfer of an inferiorly based myocutaneous flap.  相似文献   
63.
Cyclosporine is a potent immunosuppressant with low myelotoxicity. It is approved for use to prevent rejection of kidney, liver, and heart transplants, and is being investigated for possible use for suppression of graft-versus-host disease in patients who have received bone marrow transplants. Although cyclosporine is generally thought of as an immunosuppressive agent for use in conjunction with transplantation, there are investigations underway that could result in wider applications.  相似文献   
64.
Examined the effects of two instructional methods on language generalization and longterm retention in 23 adults with autism and severe to profound mental retardation. Analog language teaching employed discrete trials in a controlled setting concentrating on discrimination and identification of materials. Natural language teaching emphasized instruction through interactions that occurred incidentally to training students in the use of materials to perform functional tasks. Assessments were conducted under conditions favoring analog teaching to assure against partiality toward natural language teaching. Under such disadvantageous conditions, the methods of natural language teaching would be supported by results showing either no difference or an advantage in their favor. Both techniques increased initial and long-term generalization though the results suggest no relative superiority for either method under these assessment conditions. A significant interaction was found between prior functioning level and sequence of instruction. Because natural language teaching has many strengths, few drawbacks, and produces equal generalization and retention under disadvantageous conditions, it is strongly supported as preferable for people with autism and mental retardation.The authors acknowledge the important assistance provided by the following people: the staff and management of the Behavior Development and Learning Center at CSH/DC directed by Israel Perel, Lisa Kramer, Steve Hafferkamp, James Lowdermilk, and, finally, and especially, to the participants themselves.  相似文献   
65.
Quisqualic acid NBM lesions had no effect on water maze performance, but slightly impaired passive avoidance acquisition. GammavinylGABA treatment alone had no effect on the passive avoidance and water maze performance, but aggravated acquisition deficit in rats subjected to NBM lesioning. However, gammavinylGABA-treated NBM-lesioned rats reached control level of performance.  相似文献   
66.
The effectiveness of THA (an anticholinesterae) on scopolamine (0.4 mg/kg) and nucleus basalis (NB) lesion-induced change in neocortical spectral electroencephalography (EEG) were investigated. Scopolamine increased the amplitudes of all the spectral components in waking-immobility. In the movement-related EEG spectral values, only the alpha power was increased. THA 7.5 mg/kg, but not THA 3 mg/kg, could reverse scopolamine-induced amplitude change. NB lesioning increased delta and theta amplitudes, but decreased beta amplitude. Delta amplitude was increased during movement recordings in NB-lesioned rats. THA 7.5 mg/kg and pilocarpine 10 mg/kg, but not THA 3 mg/kg, could partially reverse the increase of delta and theta amplitudes induced by NB lesions. However, the beta power decrease could not be restored with cholinomimetics. This study demonstrates that quantitative EEG activity analysis may reflect the THA-induced restoration of the function of the cholinergic nucleus basalis.  相似文献   
67.
Technetium-99m sestamibi was used for functional investigation of the muscle perfusion of lower extremities in 35 patients with peripheral vascular disease. The aim was to test what useful information could be obtained by additional imaging of the legs in patients referred for risk stratification with dipyridamole myocardial scanning. Posterior images were acquired over the thighs and calves after postocclusive reactive hyperaemia and at rest. Inter- and intraextremity ratios and differences between the stress and rest data were used for the assessment of abnormal circulation. Arteriography was performed in every case, and surgical procedures or transluminal angioplasty in 31 patients. To estimate diagnostic accuracy, the results of99mTc-sestamibi scintigraphy were compared with those of angiography and the functional consequences of revascularization procedures. The sensitivity and specificity of99mTc-sestamibi scintigraphy were 55% and 25%, respectively, with an overall accuracy of 50%. Apparently methodological error was not responsible for these poor results. Instead, a paradoxically high uptake of the radiopharmaceutical in muscles supplied by significantly stenosed vessels was identified as the main source of both false-negative and false-positive results. This phenomenon resembles the findings of a previous study involving delayed administration of thallium-201 after exercise. In conclusion,99mTc-sestamibi scintigraphy has not proved sufficiently reliable to help in the management strategy for patients with peripheral vascular disease.  相似文献   
68.
69.
70.
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