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   156篇
  免费   10篇
儿科学   40篇
基础医学   5篇
口腔科学   1篇
临床医学   11篇
内科学   50篇
神经病学   4篇
外科学   27篇
预防医学   2篇
药学   16篇
肿瘤学   10篇
  2017年   1篇
  2016年   5篇
  2015年   5篇
  2014年   1篇
  2013年   4篇
  2012年   2篇
  2010年   1篇
  2009年   3篇
  2008年   1篇
  2007年   6篇
  2006年   3篇
  2005年   4篇
  2004年   2篇
  2003年   11篇
  2002年   4篇
  2001年   4篇
  2000年   1篇
  1999年   5篇
  1998年   9篇
  1997年   13篇
  1996年   13篇
  1995年   11篇
  1994年   15篇
  1993年   5篇
  1992年   5篇
  1991年   4篇
  1990年   3篇
  1989年   2篇
  1987年   1篇
  1986年   1篇
  1985年   3篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   5篇
  1978年   1篇
  1967年   1篇
  1957年   4篇
  1956年   2篇
  1954年   1篇
排序方式: 共有166条查询结果,搜索用时 0 毫秒
51.
52.
Definitive diagnosis of pancreatic cancer presents difficulties in that positive identification is often possible only by intraoperative biopsy. Recently, ultrasonic visualization of the pancreas has made preoperative diagnosis possible by furnishing a guide to percutaneous biopsy via a flexible 23-gauge, 0.6 mm. needle.  相似文献   
53.
54.
55.
The inhibition of Na+-H+ exchange (NHE) with amiloride analogues in vitro has been shown to prevent reperfusion arrhythmias and additional cell necrosis. Inhibition of intracellular Ca2+ overload via NHE inhibition has been suggested as a mechanism of these protective effects. The aim of this study was to examine whether treatment with amiloride analogues reduces the incidence of reperfusion arrhythmias and limits infarct size in vivo. Open-chest swine were exposed to a 30-minute left anterior descending artery (LAD) occlusion and 180 minutes of reperfusion during atrial pacing at 150 ppm. Intravenous 5-(N,N-dimethyI)-amiloride (AML, 5 μg/kg per min) was administered in the treatment group (n = 7) and intravenous saline in the control group (n = 7), starting 10 minutes before coronary occlusion. The infusion was continued during ischemia and reperfusion. The area at risk was defined by monastral blue dye and infarct size by triphenyltetrazolium chloride staining. Limb leads ECG and monophasic action potentials (MAPs) from the epicardium in the ischemic area were recorded. There was no significant difference in the size of the area at risk and hemodynamic parameters between the groups. However, the infarcted area was 0.4%± 1.0% of the area at risk in the treatment group, whereas it was 62%± 29% in the control group (P < 0.05). Pathological examination (Hematoxylin-eosin and mallory s phosphotungstic acid-hematoxylin staining) revealed that all of the infarcted area consisted of contraction band necrosis. MAP duration in both groups was significantly shortened during ischemia. After reperfusion, MAP duration in the treatment group recovered earlier than that of control group. However, there was no significant difference in the incidence of ventricular tachyarrhythmia between the groups. Inhibition of NHE with AML prevented reperfusion related cell necrosis in the in vivo swine model, but did not reduce the incidence of ventricular tachyarrhythmia.  相似文献   
56.
Infants with neuroblastoma are known to have a favorable prognosis compared to those over 1 year of age. However, there is little biological information about the age-related heterogeneity of neuroblastoma. We evaluated the biological profile comparing cases detected by mass screening with those detected clinically. A total of 238 patients with neuroblastoma were classified into four groups according to their age at diagnosis. Patients in group A were 0–5 months of age (n = 31). Patients in group B were detected clinically and were 6–11 months of age (n = 25). Patients in group C were 6–11 months of age and were detected by mass-screening (n = 97). Patients in group D were more than 12 months of age (n = 85). The age-related heterogeneity was evaluated by Kaplan-Meier survival analysis, several clinical markers (neuron specific enolase, ferritin, vanillylmandelic acid and homovanillic acid) at diagnosis, tumor Ha-ras p21 expression and tumor N-myc amplification. Infant neuroblastoma had unique features in comparison to neuroblastoma diagnosed over 12 months of age. Clinical outcome of the patients in groups A and C was quite favorable. Even patients with stage III or IV disease in group A had a favorable prognosis. However, stage IVs disease in group A was not necessarily associated with a good prognosis and the early death after diagnosis was also characteristic. The biological profile of tumors in group C was similar to that in group A but different from the profile in groups B and D. Tumors in group B had a biological profile intermediate between groups A and D. Cases detected by mass screening (group C) provided a new clinical entity with a good prognosis. The difference in biological profiles might affect their clinical outcome of respective age group. These analyses confirm the significance of prognostic markers and may help to direct an appropriate modality of treatment for the individual patient.  相似文献   
57.
A 36-residue peptide amide corresponding to the entire amino acid sequence of porcine peptide YY (PYY) was synthesized by assembling eight peptide fragments of established purity, followed by hard acid deprotection with 1m trimethylsilyl trifluoromethanesulfonate in trifluoroacetic acid. β-Cycloheptylaspartate, Asp(OChp), was employed to minimize the base-catalyzed succinimide formation. When administered to dogs, synthetic PYY was active as natural peptide in its effects on exocrine pancreatic secretion and pancreatic tissue blood flow.  相似文献   
58.
The internal thoracic artery has been favored because of its superior early and late patency for coronary artery bypass grafting (CABG) in pediatric patients. We have studied the angiographic changes of the internal thoracic artery and its side branches before and after CABG with internal thoracic artery to the left anterior descending artery. The internal thoracic artery with remaining thymic or pericardial branches was patent but showed enlargement of the branches in the early period after the operation, and a postoperative exercise test suggested a remaining ischemic lesion in the bypass. Angiogram taken 1 year after CABG demonstrated the grown internal thoracic artery with disappearance of most of the side branches, which had been enlarged 1 month after the operation. Our findings suggest the importance of ligation of the whole proximal internal thoracic artery branches to maintain good early and late patency.  相似文献   
59.
Survival rates were calculated for 251 patients with cirrhosis of the liver but without hepatocellular carcinoma, primary biliary cirrhosis, or autoimmune cirrhosis who underwent laparoscopy during the past 21 years at the authors' hospital. The survival rates were calculated by the Kaplan-Meier method. Stored serum was assayed for hepatitis B surface antigen (HBsAg) and antibodies to the hepatitis C virus (HCV). Patients with alcoholic cirrhosis had significantly better survival rates than patients with HBsAg, HCV, or both. Differences in survival rates between patients with hepatitis B and C were insignificant. In both groups, habitual drinkers had a significantly lower survival rate. The results suggested that alcohol accelerates liver damage in subjects with viral hepatitis.  相似文献   
60.
Leiomyosarcoma in childhood is very rare. This report describes the immunohistochemical study of a gastric epithelioid leiomyosarcoma in a 14 year old girl. Microscopically, the tumor showed two distinct histological patterns within the same tumor: small epithelioid cells forming a lobular pattern and spindle-shaped cells forming interlacing fascicles, but no distinct border divided the two types of cells. Immunohistochemically, vimentin was positive in all tumor cells; a-smooth muscle actin, however, was negative in small epithelioid cells and positive in spindle-shaped cells. The data revealed that the tumor had components showing two stages of morphological and biochemical differentiation. This case indicates that leiomyosarcomas might lose smooth muscle actin during malignant transformation; or, alternatively, they might arise from a primitive type of smooth muscle cell and some of them could spontaneously differentiate into mature smooth muscle cells, expressing this actin.  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