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   882篇
  免费   58篇
  国内免费   5篇
耳鼻咽喉   10篇
儿科学   32篇
妇产科学   17篇
基础医学   91篇
口腔科学   20篇
临床医学   86篇
内科学   157篇
皮肤病学   7篇
神经病学   29篇
特种医学   14篇
外科学   184篇
综合类   61篇
一般理论   1篇
预防医学   84篇
眼科学   6篇
药学   93篇
中国医学   3篇
肿瘤学   50篇
  2024年   1篇
  2023年   9篇
  2022年   23篇
  2021年   41篇
  2020年   25篇
  2019年   29篇
  2018年   37篇
  2017年   24篇
  2016年   28篇
  2015年   22篇
  2014年   33篇
  2013年   34篇
  2012年   78篇
  2011年   76篇
  2010年   34篇
  2009年   38篇
  2008年   51篇
  2007年   51篇
  2006年   30篇
  2005年   41篇
  2004年   42篇
  2003年   33篇
  2002年   21篇
  2001年   29篇
  2000年   20篇
  1999年   14篇
  1998年   8篇
  1997年   8篇
  1996年   6篇
  1995年   8篇
  1994年   4篇
  1993年   5篇
  1992年   7篇
  1991年   2篇
  1990年   3篇
  1989年   6篇
  1988年   3篇
  1987年   1篇
  1986年   2篇
  1985年   3篇
  1984年   2篇
  1982年   2篇
  1980年   1篇
  1979年   2篇
  1978年   3篇
  1976年   1篇
  1974年   1篇
  1973年   2篇
  1971年   1篇
排序方式: 共有945条查询结果,搜索用时 15 毫秒
51.
Body. Chronic stimulation of Gq-coupled receptors in the heart leads to PKC activation and myocyte hypertrophy, a precursor to heart failure. βARK1 is a G-protein-coupled receptor kinase (GRK) which phosphorylates and desensitizes agonist-occupied β-adrenergic receptors (βARs), which are critical for cardiac function. Our objective was to determine if myocardial PKC can activate βARK1 in vivo. We studied βARK1 expression by protein immunoblotting and βARK1 activity in the hearts of transgenic mice with cardiac-specific expression of a peptide which increases αPKC activity in the heart by 50% (αPKCact) versus non-transgenic controls. Data are expressed as mean ± SEM. Results were compared using Student’s t-test. Protein expression of βARK1 in myocardial extracts was not significantly different between αPKCact and control: n = 7 in each group, P > 0.05. In contrast, βARK1 activity, as measured by its ability to phosphorylate rhodopsin, was elevated 3-fold in cardiac membrane preparations from αPKCact mice versus control: 3100 ± 214 versus 1058 ± 149 densitometry units, P < 0.05, n = 6 in each group. Based on these data, it appears that αPKC can activate βARK1 in the heart. This may be an important mechanism of βAR dysfunction in the development of myocardial hypertrophy as βARK1 is the primary GRK expressed in the heart.  相似文献   
52.
A new source of hepatocytes for transplantation   总被引:2,自引:0,他引:2  
INTRODUCTION: The most effective treatment for acute or chronic liver failure is orthotopic liver transplantation. Worldwide there is a shortage of organs for transplantation. This shortage has called for research into new treatments for management of patients with liver failure. One such treatment is hepatocyte transplantation. During liver resections considerable amounts of normal liver are unavoidably resected. We aim to harvest these hepatocytes and to filter the tumor cells from them to provide a source for transplantation. MATERIALS AND METHODS: After liver resection, the largest vessel at the resected liver edge was identified and cannulated. Seglen's two-stage technique of perfusing the liver with EDTA and collagenase was performed to harvest the hepatocytes. Ep-CAM Ags are consistently present on the surface of epithelial cells and in particular in colorectal cancer cells. Therefore, MOC31 antibodies (selective Abs for Ep-CAM) attached to magnetic beads were used to target the tumor cells. These tumor cells are selectively removed using a magnet. CEA staining was then used to ensure the hepatocyte collection was tumor cell free. Five million hepatocytes were rosetted with one million HT29 CRC cells to assess the immunomagnetic filtration technique. RESULTS: The hepatocyte harvesting resulted in 864,000 viable hepatocytes to be harvested per gram of liver. Histochemical staining using CEA demonstrated 75% of the HT29 cells in the hepatocyte collection were removed after one use of magnetic beads. CONCLUSION: We have demonstrated the successful initial stages of harvesting tumor-free hepatocytes from liver resected for malignancy.  相似文献   
53.
An unusual case of two displaced intrauterine contraceptive devices (copper-T) is described in a 34 years old lady. One copper-T was found in the urinary bladder with stone formation around it and the other embedded in the posterior wall of the urinary bladder. This was managed operatively and the patient made a smooth recovery.  相似文献   
54.
Zinc in CSF of patients with febrile convulsion   总被引:2,自引:0,他引:2  
OBJECTIVE: This prospective study was carried out from July-December 1999 to see the status of zinc in CSF of children with febrile convulsion and to compare this to that of control. METHODS: Forty-two cases of febrile convulsion and 30 controls (fever without convulsion) were enrolled into the study. CSF zinc was estimated by atomic absorption spectrophotometry (AAS) in Atomic Energy Center, Dhaka and compared between the two groups. RESULTS: The mean zinc level in CSF in the study sample was 40.19mgm/L and that in control was 74.98mgm/L. This difference was statistically significant (p<0.001). CONCLUSION: The study concludes that a significantly lower of zinc exists in CSF of children with febrile. However no relationship was found between CSF zinc status with age, sex, degree & duration of fever and time of lumbar puncture after convulsion.  相似文献   
55.
Congestive heart failure (CHF) due to hyperkinetic states can occur in systemic diseases and in arteriovenous fistulas. An 18 year old Turkish male patient complaining of dyspnea and palpitations, who had suffered a stab wound to his abdomen eight months earlier, was admitted to our clinic. Auscultation revealed a systolodiastolic murmur over the entire abdomen. Chest x-rays demonstrated significant cardiomegaly. Echocardiography revealed biatrial enlargement and significant mitral and tricuspid regurgitation accompanied by dilatation of the inferior vena cava. Right heart catheterization showed increased oxygen saturation at the inferior vena cava. A diagnosis of an aortocaval fistula was made by aortography. The symptoms subsided and valvular regurgitations ceased alter surgical correction. This rare case demonstrates the significance of routine physical examination and history of the patient.  相似文献   
56.
57.
58.
Ultrasound is a well recognized imaging modality for prenatal diagnosis of fetal congenital anomalies. Reported cases are hydrops fetalis diagnosed during ultrasonic evaluation of fetal condition in the Center for Nuclear Medicine and ultrasound (CNMU), Mymensingh. Only fetal ascites was detected in one case of 26 +/- 2 wks of gestation, fetal ascites with hydramnios and thick placenta was seen in another case of 28 +/- 2 wks of gestation. In third case, there was fetal ascites, scalp edema, hydrothorax and myelomeningocele with oligohydramnios at 20 +/- 2 wks of gestation; sonographic diagnosis was hydrops fetalis with myelomeningocele. Follow up was advised in first two cases and third case was terminated electively. To decrease the mortality rate and to improve the outcome of hydrops fetalis cases appropriate prenatal investigations and therapy is needed. Recent advances in prenatal ultrasound have made possible the early detection of hydrops fetalis which is helpful for proper management in time.  相似文献   
59.
60.
Objectives: The cytological findings of 50 ST Ts were evaluated aiming to determine the role of FNA in diagnosis of STTs Methods: Fifty patients with soft tissue tumours underwent FNA in the preoperative investigation during a one year period. The smears were stained with Papanicolaou and May-Graunvald Giemsa stains. Results: Forty-four cases were reported as benign, whereas 2 were malignant. Four cases revealed insufficient material. The malignant STTs were small round cell tumour and malignant spindle cell tumour. Cytological and histological correlation could be achieved in 40 cases. The overall sensitivity and specificity were 25% and 100% respectively with overall accuracy of 80%. Conclusion: A reliable diagnosis of STTs can be made with FNA when supported by other clinical and other diagnostic data. Key words: FNA, soft tissue tumours.  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