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   1483篇
  免费   61篇
  国内免费   4篇
耳鼻咽喉   8篇
儿科学   71篇
妇产科学   13篇
基础医学   214篇
口腔科学   29篇
临床医学   113篇
内科学   247篇
皮肤病学   17篇
神经病学   143篇
特种医学   165篇
外国民族医学   2篇
外科学   157篇
综合类   129篇
一般理论   1篇
预防医学   51篇
眼科学   35篇
药学   96篇
肿瘤学   57篇
  2021年   34篇
  2019年   11篇
  2018年   10篇
  2017年   10篇
  2016年   18篇
  2015年   22篇
  2014年   17篇
  2013年   21篇
  2012年   44篇
  2011年   49篇
  2010年   46篇
  2009年   41篇
  2008年   53篇
  2007年   52篇
  2006年   74篇
  2005年   58篇
  2004年   51篇
  2003年   52篇
  2002年   56篇
  2001年   40篇
  2000年   42篇
  1999年   43篇
  1998年   48篇
  1997年   31篇
  1996年   36篇
  1995年   29篇
  1994年   38篇
  1993年   15篇
  1992年   29篇
  1991年   26篇
  1990年   30篇
  1989年   34篇
  1988年   32篇
  1987年   33篇
  1986年   33篇
  1985年   28篇
  1984年   19篇
  1983年   18篇
  1982年   13篇
  1981年   12篇
  1980年   18篇
  1979年   15篇
  1978年   15篇
  1976年   12篇
  1973年   7篇
  1972年   10篇
  1971年   9篇
  1970年   7篇
  1943年   7篇
  1936年   7篇
排序方式: 共有1548条查询结果,搜索用时 265 毫秒
91.
M-mode echocardiographic findings were compared between sickle cell anemic and healthy children. Patients were composed of two groups; Group 1: mild group with no crises, no blood transfusions at the ages of 5.0 to 13.0, total of 12 children; Group 2: severe group, with frequent crises with requirement of blood transfusions at the ages of 3.0 to 13.0 years, total of 18 children. Control group was composed of 12 healthy children aged 5.0 to 13.0. When M-mode echocardiographic findings were compared, important findings were as follows: Mean left atrium dimension was increased both in the mild and severe groups (P < 0.001) compared with controls. This finding also supports the increase in the left ventricle end-diastolic dimension in both the severe and mild groups as compared with controls (P < 0.001). The increase in end-diastolic left ventricle dimension could be due to anemia present in the patients, but there was no difference between the two patient groups. Posterior left ventricle thickness and left ventricle mass was increased in both the mild and severe groups compared with controls (P < 0.001, P < 0.05), respectively. Left ventricular fractional shortening was more or less the same with controls. In spite of left ventricular volume load and dilatation, left ventricular contraction was good and systolic function was normal, and there was no correlation between the ECHO findings and hematological indices.  相似文献   
92.
Depletion neutropenia caused by overwhelming bacterial infection is associated with fatal outcome and is an objective indicator of the severity of sepsis. Studies on controlled evaluation of exchange transfusion in the management of severe neonatal sepsis have not considered neutropenia as an inclusion critcrion, and randomized, controlled trials on evaluation of ncutrophil functions after exchange transfusion are scarce. This prompted us to carry out the present study. Septicemic neonates were enrolled if they had neutropenia and were randomized to undergo exchange transfusion (study group, n = 20) or not (controls, n= 10). Granulocyte functions were assessed using the nitro blue tetrazolium (NBT) reduction test and the staphylococcicidal index. Blood was drawn for granulocyte function tests once from controls and donors, and before, immediately after and 6 h after exchange transfusion in the study group. Mortality was 35% in the study group and 70% in controls. Gram-negative organisms accounted for 80%, in the study group and 90% in controls. Mean total leukocyte count and neutrophil count increased significantly immediately after exchange transfusion and 6 h later. Absolute band count decreased significantly immediately after exchange transfusion and incrcased 6 h later. NBT reduction in septicemic neonates in the study group, as wclras in controls. was significantly decreascd as compared to donor cells. NBT reduction improved significantly immediately after exchange transfusion and 6 h later. The valucs of the perccntage of viable staphylococci recovered from neutrophils also improved significantly immediately after exchange transfusion and 6 h later. We conclude that exchange transfusion with fresh whole blood in severe neonatal septicemia with neutropenia improves survival, increases the neutrophil count and cnhances neutrophil function.  相似文献   
93.
Extracorporeal membrane oxygenation (ECMO) is a life support technique based on modifications of heart-lung bypass technology. It is used to support severe but potentially reversible pulmonary or cardiopulmonary failure. There is increasing use of the technique for neonates and a return of interest in its use for adults. The number of non-neonatal paediatric patients receiving pulmonary support with ECMO worldwide is, however, small, and survival rates average less than 50%. Initial experience in 15 patients aged 3 months to 5 years with a high survival and low morbidity is reported.  相似文献   
94.
Acute and chronic administration of ethanol leads to alterations of the adenylyl cyclase (AC) signal transduction pathway. This study examined whether the formation of cAMP by AC in lymphocytes correlates with age in alcoholic patients and in healthy controls. Blood was drawn for preparation of lymphocyte membranes and for determination of basal, GTPgammaS-stimulated, and forskolin-stimulated AC activity from 68 actively drinking alcoholic patients (age, mean +/- SD: 45 +/- 10; range: 26-69 years) after ethanol detoxification. The patients' AC activity correlated negatively with age. In contrast, no effect of age was observed in the healthy controls (age, mean +/- SD: 42 +/- 11; range: 24-65 years). The age-related decrease in AC activity of alcoholic patients could not be attributed to the duration of regular alcohol intake. It was partly due to the large variance of AC activity in younger and middle-aged alcoholics.  相似文献   
95.
96.
Muscle sufficiency was significantly lower in 1336 children with chronic malnutrition of moderate to severe degree. Eighteen children with a chronic moderate degree of malnutrition and 8 well-nourished, age-matched controls were selected for biochemical and 31-phosphorus magnetic resonance spectroscopy (31 -P MRS) studies. The results showed that: (a) serum total protein, albumin, iron, calcium and inorganic phosphate were similar in both groups; (b) serum enzyme levels were significantly increased in the malnourished group; (c) 31-P MRS showed significantly higher means for total ATP, β-ATP, a-ATP and inorganic phosphate for the malnourished compared to the control group. In chronic malnutrition, proteins are maintained by degradation in muscle resulting in release of amino acids and enzymes. 31-P MRS studies showing increases in total ATP, β-ATP and inorganic phosphate and a decrease in phosphocreatine suggest that ATP is maintained at the cost of phosphocreatine.  相似文献   
97.
The pathology was reviewed of the early deaths identified from the first 50 neonates treated with extracorporeal membrane oxygenation (ECMO) during its introduction to the UK. Fifteen neonates died during or shortly after ECMO between August 1989 and June 1992. Data on 12 are presented (three did not have a postmortem examination). The clinical diagnoses at referral for ECMO were as follows: persistent pulmonary hypertension of the newborn (six infants), primary congenital pneumonia (one infant), community acquired pneumonia (two infants), birth asphyxia (one infant), respiratory distress syndrome (one infant), and meconium aspiration syndrome (one infant). In our group, at necropsy, five had significant haemorrhage (three intracranial, one pulmonary, one pericardial and intraventricular). Three of five infants with evidence of haemorrhage also had signs of sepsis. Six infants had evidence at necropsy of systemic sepsis, five showed evidence of severe anoxic brain injury, and four infants had cerebellar haemorrhages. Three infants had evidence of myocardial ischaemia. It is difficult to discriminate between the relative influence of the primary diagnosis, the mode of treatment, and the severity of presentation in the genesis of this pathology. It is likely that the extent and severity of some of the findings represent a pathological progression that would have been interrupted by the death of the patient, had ECMO not been instituted.  相似文献   
98.
Moyamoya disease is a progressive disease which involves the internal carotid arteries and its branches bilaterally. The disease is reported both in adults and in children. Moyamoya disease is frequently seen in Japanese patients having certain human leucocyte antigen (HLA) haplotypes including HLA-Aw24, Bw46 and Bw54. Twin cases are rarely reported in the literature. We hereby present the first Turkish monozygotic twins with moyamoya disease whose HLA haplotypes are A2, A9, B21, Bw22, Bw4, Bw6, Cw3, and DR2, DR4, DRw52, DRw53, Dq7. The patients with advanced disease were given nifedipine and intravenous immunoglobulin (400mg/kg/d for 5 days). During the 11 months of follow-up, the patients were attack free.  相似文献   
99.
The present evaluation focused on the inter-rater reliability of single items and subscales of the Positive and Negative Syndrome Scale (PANSS) before and after a standardized rater training. The results of two independent studies comprising n=23 (study I) and n= 12 (study II) psychiatrists and videotaped interviews with schizophrenic patients were analysed. Chance-corrected coefficients of rating agreement with expert standards (weighted κ) were computed for single items and subscales of the PANSS. The results clearly demonstrate the importance of rater trainings. After three training sessions, 90% of the PANSS items reached an acceptable level of reliability (κw>0.40) in both evaluated studies, and for 80% of the PANSS items values of κw>0.60 were achieved.  相似文献   
100.
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