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   421篇
  免费   39篇
  国内免费   4篇
儿科学   23篇
妇产科学   2篇
基础医学   56篇
口腔科学   3篇
临床医学   38篇
内科学   130篇
皮肤病学   7篇
神经病学   15篇
特种医学   103篇
外科学   29篇
综合类   19篇
预防医学   5篇
药学   24篇
肿瘤学   10篇
  2021年   8篇
  2020年   4篇
  2019年   11篇
  2018年   8篇
  2017年   4篇
  2016年   6篇
  2015年   4篇
  2014年   4篇
  2013年   9篇
  2012年   3篇
  2011年   5篇
  2010年   13篇
  2009年   12篇
  2008年   8篇
  2007年   14篇
  2006年   12篇
  2005年   3篇
  2004年   7篇
  2003年   6篇
  2002年   8篇
  2001年   12篇
  2000年   8篇
  1999年   11篇
  1998年   16篇
  1997年   15篇
  1996年   19篇
  1995年   5篇
  1994年   12篇
  1993年   15篇
  1992年   5篇
  1991年   7篇
  1990年   11篇
  1989年   16篇
  1988年   13篇
  1987年   23篇
  1986年   16篇
  1985年   26篇
  1984年   5篇
  1983年   7篇
  1982年   10篇
  1980年   5篇
  1979年   8篇
  1978年   9篇
  1977年   9篇
  1976年   5篇
  1975年   11篇
  1974年   2篇
  1973年   5篇
  1972年   2篇
  1971年   2篇
排序方式: 共有464条查询结果,搜索用时 0 毫秒
21.
22.
23.
Multiple intracranial aneurysms have been reported in association with polycystic disease of the kidney, brain tumor, pituitary adenoma and coarctation of the aorta. We report the association of multiple aneurysms with primary hyperaldosteronism due to bilateral adrenal hyperplasia in an 18 year old left-handed man who presented with subarachnoid hemorrhage and arterial hypertension. We report the excellent outcome of this patient in spite of a difficult and surgical management. Ligation of all three intracranial aneurysms was performed after an extra-intracranial arterial bypass was done as a protective measure.  相似文献   
24.
Emotional stress acutely and repetitively causing blood pressure increase or aggravating existing hypertension is usually not reflected by norepinephrine and epinephrine increase but by a sudden rise of dopamine, the third "defensive" catecholamine coping with the damaging neuropsychological and cardiovascular actions of the first two. This double-edged sympathetic response to emotional stress evolves during human lifespan and long-term evolution of hypertension. In the course of philogenesis it carries a potential mismatch between the normal physiology of the human dopaminergic system and current environmental (emotional particularly) conditions in industrialized countries. This offers a rational support to a mental stress-cardiovascular diseases relationship proposed 40 years ago in a WHO report which followed a memorable 1960 Prague Hypertension Meeting.  相似文献   
25.
26.
The cosecretion of pancreatic lipase and colipase are important in normal fat digestion. As adsorption of phosphatidylcholine to the lipid substrate interferes with lipase activity, hydrolysis to lysophosphatidylcholine with subsequent desorption is also essential for fat digestion. There are some data regarding the secretion of pancreatic phospholipases in normal adults but none in children or patients with pancreatic disease. In the present study, we aimed a) to develop an accurate fast assay method to measure phospholipase A(2) and b) to determine the secretion rate of pancreatic phospholipase A(2) and whether it is cosecreted with lipase and colipase in children with exocrine pancreatic dysfunction. Nine male patients aged 0.5 to 16 y (seven with cystic fibrosis, two with malabsorption) underwent pancreatic stimulation tests. Their colipase and lipase secretion rates were measured by titrimetric methods and phospholipase A(2) and A(1) by phosphorus magnetic resonance spectroscopy ((31)P NMR). It was found that the phospholipases, colipase, and lipase were absent in the two patients with pancreatic insufficiency. In patients with normal absorption, there were marked inter-and intrasubject variations of lipase, colipase, and phospholipase secretion rates that were consistent with the degree of exocrine pancreatic dysfunction. However, in the three 20-min stimulation periods of the pancreatic function test, pancreatic phospholipase is cosecreted with lipase and colipase, and average colipase and phospholipase A(2) secretion rates follow a similar or parallel pattern. These findings are consistent with the important role of pancreatic phospholipases in intestinal phospholipid hydrolysis leading to the desorption of phospholipids from the lipid substrate and enhancing lipid hydrolysis and phospholipid absorption.  相似文献   
27.
Labetalol is an orally active adrenoreceptor-blocking drug which is a competitive antagonist of both alpha- and beta-adrenoreceptor sites. Thirty patients with essential hypertension were admitted to the study. The mean of initial systolic and diastolic blood pressures of these patients was 160/101 +/- 3/1 supine and 155/104 +/- 3/1 mm Hg standing, and the mean blood pressures at the end of the 16 week trial was 142/90 +/- 4/2 supine and 131/91 +/- 3/2 mm Hg standing. The average dose of labetalol was 546 mg: eight patients received a dose of 300 mg, seven a dose of 600 mg, six a dose f 900 mg, and two a dose of 1,200 mg. The patients who needed the highest doses of labetalol had an initial lowering of their blood pressures followed by a gradual increase despite the higher doses of labetalol. There was no significant change in the mean peripheral renin activity value. Side effects were reported by 18 of the 30 patients, but only 1 patient withdrew for this reason. Two patients were considered to be treatment failures. Overall, labetalol was found to be an effective antihypertensive agent in 15 patients.  相似文献   
28.
Balb/c mice were immunized with a mixture of fibrin degradation products (XDPs) prepared by complete lysis of a human blood clot by tissue-type plasminogen activator and purified by immunoaffinity chromatography. Spleen cells of the mice were fused with P3 X 63 Ag 8653 myeloma cells. A clone (FDP 14) was selected that produces monoclonal antibodies (MoAbs) of the IgG1 kappa type that react with a neoantigenic determinant exposed in these XDPs, but not in intact fibrinogen or in fibrin monomers. Furthermore, the MoAb is reactive with some pure, individual degradation products of fibrinogen (fragments X, Y, E, and the N-terminal disulphide knot) and with the fibrinogen B beta-chain but not with A alpha- and gamma-chains or with fragments D, FCB-2 and FCB-3. Comparison of the known primary structures of these fibrinogen fragments indicates that the stretch B beta 54-118 comprises at least an important part of the epitope recognized by FDP-14. Apparently, this stretch contributes importantly to a neoantigenic determinant that is not functional in intact fibrinogen and fibrin monomer and that can be made functional by reduction of fibrinogen, or by digestion with plasmin or CNBr.  相似文献   
29.
The authors present the radiographic features of a previously incompletely delineated bone dysplasia, which they call spondylometaphyseal dysplasia, corner fracture type. This is a dominant heritable condition associated with short stature and developmental coxa vara. The progressive hip deformity usually causes significant disability requiring surgical correction. Developmental coxa vara, simulated corner fractures of long tubular bones, and vertebral body abnormalities result in a diagnostic constellation. Knowledge of these distinctive radiologic features allows accurate diagnosis, which in turn should lead to appropriate genetic counseling and possibly to earlier, more efficacious surgical treatment of the coxa vara.  相似文献   
30.
A 31P NMR method based on pH dependent variation of the chemical-shift-difference between the resonances of orthophosphate and methylphosphonate was used to measure simultaneously intracellular pH (pHi) and extracellular pH (pHc) during long term storage of erythrocytes; pH was determined at both 4 degrees C and 37 degrees C. An equation describing the equilibrium distribution of membrane-permeant ions was derived by consideration of the electrochemical and osmotic constraints in the RBC suspension. Calculations using the model-equation and the measured pHi yielded the Donnan ratio and therefore pHo; the relationship between experimentally determined pHi and pHo values was accurately predicted by the model. Sensitivity analysis of the model-equation revealed that the observed increase in transmembrane pH gradient during storage is principally due to the alteration of the total net charge of intracellular (poly)-anions.  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