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   9217篇
  免费   1023篇
  国内免费   15篇
耳鼻咽喉   73篇
儿科学   185篇
妇产科学   295篇
基础医学   1351篇
口腔科学   237篇
临床医学   894篇
内科学   1566篇
皮肤病学   208篇
神经病学   662篇
特种医学   607篇
外科学   1524篇
综合类   253篇
现状与发展   1篇
一般理论   7篇
预防医学   975篇
眼科学   209篇
药学   557篇
中国医学   2篇
肿瘤学   649篇
  2021年   129篇
  2020年   91篇
  2019年   167篇
  2018年   173篇
  2017年   137篇
  2016年   139篇
  2015年   145篇
  2014年   197篇
  2013年   283篇
  2012年   385篇
  2011年   402篇
  2010年   236篇
  2009年   269篇
  2008年   417篇
  2007年   399篇
  2006年   425篇
  2005年   403篇
  2004年   352篇
  2003年   325篇
  2002年   316篇
  2001年   295篇
  2000年   298篇
  1999年   254篇
  1998年   128篇
  1997年   116篇
  1996年   122篇
  1995年   131篇
  1994年   117篇
  1993年   101篇
  1992年   228篇
  1991年   200篇
  1990年   187篇
  1989年   220篇
  1988年   159篇
  1987年   194篇
  1986年   170篇
  1985年   183篇
  1984年   150篇
  1983年   121篇
  1982年   100篇
  1981年   62篇
  1980年   74篇
  1979年   115篇
  1978年   71篇
  1977年   74篇
  1976年   62篇
  1975年   60篇
  1974年   74篇
  1973年   70篇
  1968年   63篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
Bould  M D; Hunter  D; Haxby  E J 《CEACCP》2007,7(2):66
Contin Educ Anaesth Crit  相似文献   
3.
Arousal from propofol   总被引:1,自引:0,他引:1  
  相似文献   
4.
The potential cytoprotective actions of a novel nicotinic agent 2,4-dimethoxybenzilidene anabaseine (DMXB) were investigated in differentiated PC12 cells and transected rat septal cholinergic neurons in vivo. In NGF-differentiated PC12 cells, removal of both NGF and serum led to cell loss, a reduced % of cells expressing neurites, the release of lactate dehydrogenase, and a decrease in total cellular protein. Cell loss was apparent within 24 h, and remained constant between 4–8 days post-NGF removal. NGF alone (100 ng/ml), DMXB (10 μM), but not nicotine (10 μM), prevented these cell and neurite losses. DMXB-induced cytoprotection was blocked by 1 μM mecamylamine. DMXB (1 mg/kg, ip) injected twice but not once per day protected cholinesterase-staining septal neurons from retrograde degeneration following unilateral fimbrial transections. The twice per day DMXB injection-protocol also decreased cell roundness among cholinesterase-staining cells in the lesioned septal hemisphere compared to saline-injected animals. These studies suggest that DMXB may exert cytoprotective activity in NGF-sensitive neuronal populations. © 1994 Wiley-Liss, Inc.  相似文献   
5.
n = 69) normal; Group B (n= 29), abnormal, severe defects; Group C (n= 56), abnormal, mild–moderate defect. RCA detected 32 defects in Group B: 10 internal carotid (ICA), seven endpoint flaps, two kinks, one dissection; 16 external carotid (ECA), 10 severe endpoint defects and six total occlusion; six common carotid (CCA), five irregular proximal shelfs, one web. Thirty of 32 defects were successfully repaired as confirmed by normal repeat RCA studies; one ECA defect was not repaired and the ICA dissection was irreparable. In Group C, 67 mild–moderate defects were identified, but not corrected. These included <30% stenosis in the ICA (12), ECA (18), CCA (24), and vein patch corrugation or irregularity (13). For the entire series the postoperative ICA occlusion rate was 2% (3/154), stroke rate 2.6% (4/154), and a subsequent >50% restenosis rate of 7% (11/154). The yield from routine carotid completion arteriograms was significant, with 19% of studies identifying a severe defect that required repair. Although the difference in stroke rates and restenosis between the different groups did not reach statistical significance, patients with normal intraoperative arteriograms initially or after correction of a significant RCA defect had no early carotid occlusion (p= 0.05, Fisher's exact test) compared to patients with residual RCA defects. All early carotid occlusions occurred in patients with unrepaired defects. We conclude that RCA is an important method of quality control after CEA and exerts a subtle, but real, reduction in postoperative complications.  相似文献   
6.
PURPOSE: Little is known about use and expenditure patterns of children's eye-care services and about possible disparities in care among children. This report describes the use and expenditure patterns of eye care and non-eye care services for children under 18 years old in the United States. METHODS: Levels of use and expenditure were estimated using self-reported information from the nationally representative Medical Expenditure Panel Surveys (1996-2001) for 48,304 subjects under 18 years old from randomly selected households in the United States. Means presented for children with and without diagnosed eye conditions were adjusted for child and family characteristics using generalized linear models. RESULTS: Children with diagnosed eye conditions had higher levels of use and expenditure than children without diagnosed conditions. Families of children with diagnosed eye conditions incurred higher out-of-pocket expenditures. Black children and children living below 400% of the federal poverty level had lower levels of use and expenditure, indicating that they received fewer and less intensive services. CONCLUSIONS: Children with diagnosed eye conditions experienced higher overall use of health care. Some groups of children appear to be underserved. Estimates of use and expenditure patterns, stratified by socioeconomic factors, will be needed to plan for future delivery of children's eye and vision care services and to assess progress toward Healthy People 2010 goals.  相似文献   
7.
Edited by Lauren Dundes. Walnut Creek (CA): Altamira Press, 2003. 239 pages. $27.95, paperback, $75.00, hardback.  相似文献   
8.
BACKGROUND: Previous structural magnetic resonance (MR) research in patients with posttraumatic stress disorder (PTSD) has found smaller hippocampal volumes in patients compared with control subjects. These studies have mostly involved subjects who have had PTSD for a number of years, such as war veterans or adult survivors of childhood abuse. Patients with recent-onset PTSD have rarely been investigated. To our knowledge only one other study has investigated such a group. The aim of this study was to compare hippocampal volumes of patients with recent onset PTSD and nontrauma-exposed control subjects. METHODS: Fifteen patients with PTSD, recruited from an accident and emergency department, were compared with 11, non-trauma-exposed, healthy control subjects. Patients underwent a structural MR scan soon after trauma (mean time = 158 +/- 41 days). Entire brain volumes, voxel size 1 x 1 x 1 mm, were acquired for each subject. Point counting and stereology were used to measure the hippocampal and amygdala volume of each subject. RESULTS: Right-sided hippocampal volume was significantly smaller in PTSD patients than control subjects after controlling for effects of whole brain volume and age. Neither left nor total hippocampal volume were significantly smaller in the PTSD group after correction. Whole brain volume was also found to be significantly smaller in patients. There were no differences in amygdala or white matter volumes between patients and control subjects. CONCLUSIONS: This result replicates previous findings of smaller hippocampal volumes in PTSD patients, but in an underinvestigated population, suggesting that either smaller hippocampal volume is a predisposing factor in the development of PTSD or that damage occurs within months of trauma, rather than a number of years. Either of these two hypotheses have significant implications for the treatment of PTSD. For instance, if it could be shown that screening for hippocampal volume may, in some cases, predict those likely to develop clinical PTSD.  相似文献   
9.
Traumatic pseudoaneurysms of the superior mesenteric artery (SMA) are extremely rare. We describe two cases of posttraumatic proximal SMA pseudoaneurysms with symptoms of gastric outlet obstruction. Repair was accomplished by aorta-SMA bypass with saphenous vein. Injuries to the proximal SMA are easily missed at laparotomy, especially if intestinal ischemia or hematomas are absent. Recognition and repair are stressed to avoid the complications associated with pseudoaneurysm formation.  相似文献   
10.
Revascularization of the ischemic diabetic extremity presents a significant diagnostic and technical challenge. The in situ saphenous bypass provides a conduit that allows revascularization to arteries at the ankle and proximal foot. Evaluation of the distal circulation, the adequacy of the saphenous vein, and routine follow-up after bypass, along with the operative procedure, are described. Balloon inflow occlusion arteriography, duplex mapping of the saphenous vein, operative technique, and follow-up protocol are discussed.  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