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   791篇
  免费   38篇
  国内免费   7篇
耳鼻咽喉   6篇
儿科学   68篇
妇产科学   31篇
基础医学   82篇
口腔科学   56篇
临床医学   49篇
内科学   181篇
皮肤病学   15篇
神经病学   68篇
特种医学   21篇
外科学   133篇
综合类   10篇
预防医学   21篇
眼科学   33篇
药学   43篇
肿瘤学   19篇
  2024年   2篇
  2023年   19篇
  2022年   23篇
  2021年   47篇
  2020年   31篇
  2019年   30篇
  2018年   28篇
  2017年   21篇
  2016年   33篇
  2015年   37篇
  2014年   39篇
  2013年   51篇
  2012年   67篇
  2011年   47篇
  2010年   32篇
  2009年   31篇
  2008年   56篇
  2007年   43篇
  2006年   60篇
  2005年   39篇
  2004年   31篇
  2003年   23篇
  2002年   16篇
  2001年   9篇
  2000年   6篇
  1999年   3篇
  1998年   3篇
  1997年   1篇
  1996年   3篇
  1992年   1篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1979年   1篇
排序方式: 共有836条查询结果,搜索用时 15 毫秒
51.
52.
Serological markers for Chlamydia pneumoniae were investigated by using the microimmunofluorescence (MIF) test in various age and patient groups in a specific area in Turkey. IgG seropositivity to C. pneumoniae was 64.3% and 18.7% in healthy adults and children, respectively. The highest positivity rate (77%) was in the 15–19 age group. Among the groups investigated, serological findings revealed a possible etiological association between C. pneumoniae and the clinical condition in the groups with acute myocardial infarction, atypical pneumoniae and chronic obstructive pulmonary disease.  相似文献   
53.
54.
Comparison of Prosthetic Materials in Incisional Hernia Repair   总被引:5,自引:0,他引:5  
Purpose Incisional hernias are not uncommon after abdominal surgery, but their repair is associated with a high risk of complications, including adhesions and recurrence. Many different types of meshes and adhesion barriers have been developed in an attempt to overcome these problems, some of which we have assessed in a rat model.Methods We made a full-thickness 1.5 × 2.5-cm abdominal wall defect in 30 Sprague-Dawley rats, which were divided into three groups according to the materials used for repair: 2 × 3-cm polypropylene mesh (group 1); expanded polytetrafluoroethylene (PTFE) with double-layer polypropylene mesh (group 2); or polypropylene mesh with oxidized cellulose adhesion barriers (group 3). We assessed adhesion formation, tensile strength, and histopathologic findings.Results The mean adhesion scores were 3.3, 1.3, and 0.7, in groups 1, 2, and 3, respectively (P < 0.001). The area involved by adhesions was significantly greater in group 1 than in groups 2 or 3 (P < 0.01, P < 0.05), but there was no significant difference between groups 2 and 3 (P < 0.05). The tensile strength in group 2 was less than that in groups 1 or 3 (P < 0.01, P < 0.05), but there was no significant difference between groups 1 and 3 (P > 0.05).Conclusion Although there was less adhesion formation with PTFE and oxidized cellulose, PTFE not only impaired the tensile strength, but also induced fibrosis and inflammation. An oxidized cellulose adhesion barrier can be safely used in incisional hernia repair to prevent intra-abdominal adhesions.  相似文献   
55.
Three clinical phenomena have been defined in the last decade in patients with diabetes mellitus as a dangerous iatrogenic sequel of hypoglycemia. These are hypoglycemia unawareness, defective glucose counterregulation and a lowered hypoglycemic threshold for hypoglycemic symptoms. Former mild hypoglycemia episodes cause a decrease and a delay in the protective hormonal counterregulatory response and warning symptoms in subsequent episodes, and in the absence of these, risk of severe hypoglycemia increases considerably. It has been demonstrated that when protection is provided against hypoglycemia with strict monitoring programs designed to avoid even mild hypoglycemia episodes, blunted autonomic symptoms and counterregulatory hormonal responses are rectified. Therefore, the best course of action in the treatment of pediatric diabetes mellitus is frequent blood sugar measurements, flexible multiple dose insulin regimens facilitating insulin dose adjustments as required, and a diet. In order to implement this, it is essential to organize an intensive training program with the patient and family, and to provide psychological support and close coordination with the diabetes treatment team.  相似文献   
56.
The incidence studies on hypoglycemia in Type 1 Diabetes have revealed that the younger the child the more frequent and severe are the hypoglycemic episodes. The brain does not store glycogen and perform gluconeogenesis, it relies on a continuous supply of glucose from blood. There are several studies demonstrating the brain's ability to use lactate, alanine and ketone as alternative fuels yet there is no evidence showing that this mechanism works in diabetic individuals. During hypoglycemia, cerebral blood flow increases very little in children. It is unlikely that this mechanism alone explains the maintenance of glucose utilization. Up regulation of GLUT transporters may be an additional or alternative protective mechanism. Severe hypoglycemic episodes experienced particularly in early childhood can cause deterioration in neurocognitive functions. There are significant individual differences in terms of vulnerability to hypoglycemia. Adaptive responses to hypoglycemia might vary according to both the degree and frequency of prior hypoglycemia and the presence of structural brain changes induced by chronic hyperglycemia.  相似文献   
57.
Total anomalous pulmonary venous return (TAPVR) is a rare congenital pathology. Early diagnosis and urgent surgery are life-saving, especially in newborns with pulmonary venous obstruction, which is most commonly seen with infracardiac type. A three-day-old baby boy presented to another clinic with tachypnea and cyanosis. Initial work-up aimed at ruling out persistant pulmonary hypertension, respiratory distress syndrome and pneumonia. Acute pulmonary edema then developed, and on echocardiography obstructive type infracardiac TAPVR was suspected. Cardiac catheterization was done for definitive diagnosis. Urgent surgery was undertaken and pulmonary veins were anastomozed to left atrium with posterior approach. Patient was extubated at 10th day and discharged after three weeks. During one-year follow-up the patient was free of symptoms. Infracardiac type TAPVR is a rare pathology in which early diagnosis and urgent surgery with special postoperative case are mandatory for survival.  相似文献   
58.
Case report A 58-year-old male was admitted with headache to our neurosurgery clinic. His neurological examination revealed slight left hemiparesis. The radiological evaluation with contrast administred magnetic resonance imaging (MRI) scan demonstrated a right temporo-parietal ring enhancing mass lesion surrounded by edema which was resembling a typical glioma (Fig. 1). The patient was operated on via a temporo-parietal craniotomy and an arteriovenous malformation surrounded by abnormal glial tissue was observed during the exposure. A nidus supplied by several branches arising from the middle cerebral artery (MCA) was obvious. The venous drainage of the malformation was to the superficial venous system. The observed arterial feeders and the draining vein were coagulated and the nidus was macroscopically totally excised. The frozen examination from surrounding glial tissue revealed a high grade glioma. The tumor was also macroscopically totally excised. Postoperatively, the cerebral angiogram demonstrated a right temporal arteriovenous malformation with a centrally excised nidus. The remaning major feeders involved the angular gyrus and the posterior temporal arteries. The venous drainage was to the straight and sigmoid sinuses (Fig. 2). The final histopathological examination of the specimen revealed an arteriovenous malformation surrounded by a high grade glioma (Fig. 3). The patient refused a second operation for total removal of the AVM. Postoperatively, he is doing well with improvement of his left hemiparesis.  相似文献   
59.
We investigated the changes in renal excretion of calcium, sodium, and potassium in asthmatic children treated with inhaled budesonide, an inhaled glucocorticoid. Twenty-two asthmatic patients (7 female, 15 male, mean age 10.1±4.3 years) treated with 400–600 g/day inhaled budesonide and 23 healthy children (6 female, 17 male, mean age 10.2±2.8 years) were enrolled in the study. The parameters recorded were serum sodium, potassium, calcium, phosphorus, alkaline phosphatase (ALP), type I collagen carboxyterminal telopeptide (ICTP), osteocalcin, intact parathyroid hormone (PTH) levels, first spot morning urine calcium/creatinine ratio, sodium/potassium ratio, and daily renal calcium excretion rate (UCa-ER). These parameters were measured in the control group and pre- and post-budesonide treatment in asthmatic children. Serum electrolytes, ALP, PTH, ICTP, and UCa-ER were in the normal ranges and were not significantly different between controls and asthmatic children. Serum levels of ICTP increased, while levels of osteocalcin decreased after budesonide therapy in the asthmatic group (P=0.001, P=0.005). UCa-ER was decreased after budesonide therapy in asthmatics (P=0.000). In conclusion, moderate doses of inhaled budesonide cause hypocalciuria and decreased bone turnover. These results may be attributed to a mechanism compensating for decreased absorption of calcium in the gut due to the topical effect of swallowed budesonide rather than the systemic effects of the drug. Increased bone metabolism and decreased turnover may have an important role in this compensatory mechanism.  相似文献   
60.
A case of dens invaginatus in a mandibular second primary molar of an eleven-year-old boy is presented. The tooth was extracted and examined by scanning electron microscopy. SEM findings demonstrated the presence of defective enamel and cementum in the pulp chamber. Dentinal tissues were also irregular and had fewer and thinner tubules. This case of dens invaginatus in primary molar is an unusual case of the malformation being the only one in the literature.  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