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   2628篇
  免费   101篇
  国内免费   19篇
耳鼻咽喉   59篇
儿科学   116篇
妇产科学   203篇
基础医学   197篇
口腔科学   104篇
临床医学   234篇
内科学   700篇
皮肤病学   33篇
神经病学   126篇
特种医学   72篇
外科学   514篇
综合类   53篇
预防医学   76篇
眼科学   92篇
药学   95篇
中国医学   7篇
肿瘤学   67篇
  2023年   12篇
  2022年   16篇
  2021年   35篇
  2020年   31篇
  2019年   46篇
  2018年   61篇
  2017年   57篇
  2016年   85篇
  2015年   93篇
  2014年   108篇
  2013年   157篇
  2012年   220篇
  2011年   216篇
  2010年   134篇
  2009年   120篇
  2008年   178篇
  2007年   215篇
  2006年   179篇
  2005年   184篇
  2004年   159篇
  2003年   127篇
  2002年   95篇
  2001年   68篇
  2000年   40篇
  1999年   44篇
  1998年   9篇
  1997年   10篇
  1996年   6篇
  1995年   5篇
  1994年   3篇
  1993年   2篇
  1992年   7篇
  1991年   4篇
  1990年   5篇
  1989年   5篇
  1988年   1篇
  1986年   2篇
  1985年   2篇
  1984年   2篇
  1983年   2篇
  1973年   3篇
排序方式: 共有2748条查询结果,搜索用时 31 毫秒
1.
Conclusions: This study revealed a significant correlation between red-green-blue (RGB) values of tympanic membrane (TM) images and the presence of effusion in the middle ear. These results confirm that endoscopic RGB evaluation is a rapid and non-invasive procedure yielding objective results. Objective: To investigate, in cases of otitis media with effusion (OME), the correlation of the TM color changes with the presence and viscosity of the effusion in the middle ear. Methods: Endoscopic images of the TMs of 52 patients (group 1) and 52 healthy controls (group 2) were taken during their otologic examinations. RGB values of particular points were measured on the TM images of both groups. Additionally, in group 1 the viscosity of each effusion taken by paracentesis during surgery was also measured intraoperatively with a viscometer. Patients with viscosity values lower and higher than 450 cP (centipoise) were subdivided into groups 1a and 1b, respectively. Results: Study and control groups were comparable regarding the number of patients and their mean ages (p > 0.05). Statistically significant differences were found in RGB values of the TM between groups 1 and 2, but not between groups 1a and 1b.  相似文献   
2.
3.
Abstract – This report describes an esthetic, conservative, and economical alternative restoration technique for a fractured central incisor using the patient’s own tooth crown piece and a bondable reinforcement glass fiber. Although the long‐term durability of this adhesive post core restoration remains unknown, it remains successful after 1 year.  相似文献   
4.
5.
Oxygen-derived free radicals have been implicated in the pathogenesis of tissue injury after ischaemia-reperfusion. Caffeic acid phenethyl ester (CAPE), an active ingredient of honeybee propolis, has been identified as having potent antioxidant and anti-inflammatory properties. We evaluated the ability of CAPE applied intraperitoneally in reducing tissue injury after ischaemia-reperfusion. To investigate whether treatment with CAPE modifies the concentrations of the endogenous indices of oxidant stress, we examined its effects on a model of flap ischaemia-reperfusion injury in rats. CAPE (10 micromol/kg) was given through the peritoneum before reperfusion. CAPE given intraperitoneally had an inhibitory effect on tissue injury after ischaemia-reperfusion comparable to that of a control group. The anti-inflammatory and antioxidant properties of CAPE may contribute to its suppression of tissue injury.  相似文献   
6.
Prophylactic antibiotic use in childhood burns is controversial. The efficiency of antibiotic prophylaxis in 77 pediatric burn patients was evaluated. Forty-seven patients received prophylactic antibiotics (Group AP), while 30 patients received no prophylaxis (Group NP). Age, wound depth, day of admission, mechanism of burn injury, type of dressings were similar for both groups (p > 0.05). Wound infection rates were 21.3 % in Group AP and 16.7 % in Group NP (p > 0.05). S. aureus, Enterobacter spp., P. aeruginosa, and E. coli were the most common microorganisms. Patients with wound colonization and infection had a larger burned total body surface area (BTBSA) in both groups (p < 0.01). Eight patients had clinical sepsis. All but one of the septic patients were from Group AP. Associated infections of the upper and lower respiratory tract (16), urinary tract (7), and otitis media (2) were more common in Group AP. One patient died from sepsis in Group AP. Hospital stays were longer in Group AP (21.7 +/- 16.4 vs. 13.5 +/- 10 days; p < 0.05). Antibiotic prophylaxis in childhood burns does not reduce the rate of wound infection. Age, wound depth and BTBSA are not critical variables for prophylaxis. Reinforcing the use of culture-specific antibiotics for more beneficial and cost-effective results in the treatment of childhood burns is recommended.  相似文献   
7.
The role of surgery in intraabdominal Burkitt's lymphoma remains controversial and different opinions are present in the literature. In our institution, forty patients (30 boys and 10 girls) with intraabdominal Burkitt's lymphoma with ages ranging from 3 to 12 years have been treated and followed from 1989 through 2000. In ten cases, the patients underwent surgery because of their acute abdominal diseases (intestinal obstruction in 5, intussusception in 3, intestinal perforation in one, and acute appendicitis in one). The remaining thirty patients were referred to our clinic because of their abdominal masses, pain, anorexia and fatigue. Twelve children had localized tumors and total resection could be performed. There was one death in this group due to central nervous system involvement during chemotherapy. In the remaining 28 children, extensive intraabdominal diseases were detected. In four of them, debulking procedures were performed, while in 24 children only biopsies could be made; 8 of them underwent a second-look operation. In the debulking procedures group, two children were lost (50 %) due to tumorlysis and acute renal failure. In the biopsy group, there were six deaths (25 %). All patients received chemotherapy after operative recovery. In conclusion, our results suggest that when the tumor is localized, total resection results in a good outcome. However, in the presence of extensive intraabdominal diseases instead of resection, the operation should be limited to biopsy only.  相似文献   
8.
This study aims to evaluate the effects of gamma-hydroxybutyrate (GHB) after spinal cord trauma (SCT). Twenty rabbits were divided equally into four groups: group I was the sham-operated group, group II suffered from SCT but received no treatment, group III was given a dose of 400 mg/kg of GHB intravenously before SCT and group IV received the same dose after SCT. Cerebrospinal fluid (CSF) samples were obtained 30 min before SCT (T(0)), at 60 (T(1)) and 120 min (T(2)) after SCT. There was a threefold increase in lactate levels from baseline value at T(2) in group II, while statistically significant elevation of the lactate levels were not observed in groups III and IV. Glucose levels at T(1) and T(2) were significantly lower in groups III and IV compared with the control group. The findings of this study demonstrate that GHB can control the increase of CSF lactate and glucose levels following SCT and that this metabolic effect may be associated with neuroprotective physiological changes.  相似文献   
9.
Celik  I.  Stinner  B.  Thiel  T.  Bauhofer  A.  Rothmund  M.  Dietz  W. 《Inflammation research》2004,53(2):S116-S121
Objective:Antibiotic prophylaxis is used in many surgical procedures but there are frequent cardiovascular instabilities following antibiotics in perioperative period. A clinic modelling randomised trial (CMRT) in pigs was developed to compare the effects of 2 commonly used antibiotic combinations on cardiovascular stability during major surgery. Materials and methods:Thirty pigs (both sexes) were randomised into 3 groups, receiving either saline (placebo), co-amoxiclav or cefuroxime/metronidazole in clinically relevant doses as antibiotic prophylaxis. A laparotomy was performed and the abdomen remained open. Surgical complications were simulated by removing one third of the blood volume. For fluid resuscitation, 500 ml hetastarch (HAESTM) were infused rapidly (therapy of complication) and polymyxin B (15 mg/kg bodyweight) was applied for induction of histamine release reactions (complication of therapy). The main end points were histamine release reactions, these were classified by 2 blinded investigators. Results:Neither cardiovascular changes nor histamine release reactions were detected immediately after the administration of antibiotics or placebo alone. Plasma histamine concentrations increased after bleeding in the co-amoxiclav group (p < 0.05). After fluid resuscitation and induction of anaphylactoid reactions, the median histamine release and cardiovascular changes were not significantly different between the groups. However, the incidence of typical histamine release related reactions differed significantly between the groups: 8/10 for the controls, 6/10 in the co-amoxiclav and 2/10 in the cefuroxime/metronidazole group (p < 0.05). Conclusions:The stability and reproducibility of this model clearly demonstrated the concept of a ‘clinic modelling randomised trial’ as a useful tool. Antibiotic prophylaxis influences the organism’s capability to cope with intraoperative bleeding and fluid resuscitation problems. Indeed antibiotic prophylaxis may be beneficial. These effects of antibiotics could only be demonstrated in complex surgical models. Thus new antibiotics should be investigated in complex animal models prior to prospective randomised clinical trials or usage in clinical practice.  相似文献   
10.
Glomerular changes in BK virus nephropathy   总被引:10,自引:0,他引:10  
This study seeks to define the glomerular changes that are associated with human BK virus nephropathy (BKVN). It is based on histopathologic review of 124 biopsies showing light-microscopic changes of viral nephropathy. The diagnosis of BKVN was confirmed by immunohistochemistry or by in situ hybridization. Histological lesions were scored by the Banff 97 criteria for renal allograft pathology and were correlated with clinical parameters. Viral cytopathic effect in the parietal Bowman's capsular epithelium was seen in 21/124 (17%) biopsies. Immunohistochemistry showed infection of Bowman's capsular epithelium in an additional 15/124 (12%) biopsies. Crescents were found in 15/124 (12%) samples. Glomerulitis exceeding grade Banff g1 was only occasionally shown (4/124=3% biopsies). Other pathologic lesions documented include mild increase in mesangial matrix in 23% biopsies, aneurysmal dilatation of glomerular capillaries in 28%, ischemic glomerulopathy in 62%, and chronic transplant glomerulopathy graded as mild (cg1) in 62% of biopsies and as moderate (cg2) in 2/124 (1.9%) biopsies. These findings show that infection of the glomerular epithelium cells can occur in a subset of patients with BKVN, most often in biopsies with high viral load in the tubular epithelium. Isolated crescents can occur in BKVN biopsies, but rapidly progressive glomerulonephritis is not observed. Two biopsies showed electron-dense deposits on ultrastructural examination, but a cause and effect relationship to BK virus infection could not be established.  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