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   2035篇
  免费   88篇
  国内免费   20篇
耳鼻咽喉   70篇
儿科学   161篇
妇产科学   83篇
基础医学   149篇
口腔科学   68篇
临床医学   178篇
内科学   405篇
皮肤病学   34篇
神经病学   113篇
特种医学   100篇
外科学   419篇
综合类   28篇
预防医学   35篇
眼科学   78篇
药学   50篇
中国医学   5篇
肿瘤学   167篇
  2023年   13篇
  2022年   16篇
  2021年   32篇
  2020年   23篇
  2019年   30篇
  2018年   43篇
  2017年   34篇
  2016年   60篇
  2015年   69篇
  2014年   92篇
  2013年   149篇
  2012年   160篇
  2011年   162篇
  2010年   96篇
  2009年   100篇
  2008年   184篇
  2007年   170篇
  2006年   160篇
  2005年   157篇
  2004年   143篇
  2003年   79篇
  2002年   79篇
  2001年   30篇
  2000年   9篇
  1999年   10篇
  1998年   9篇
  1997年   7篇
  1996年   1篇
  1995年   2篇
  1994年   4篇
  1993年   5篇
  1992年   6篇
  1991年   2篇
  1988年   1篇
  1986年   2篇
  1985年   1篇
  1981年   1篇
  1975年   1篇
  1955年   1篇
排序方式: 共有2143条查询结果,搜索用时 15 毫秒
101.
BACKGROUND AND PURPOSE: Endoscopic subureteral injection of tissue-augmenting substances has become an alternative to antibiotic prophylaxis and open surgery for the management of vesicoureteral reflux (VUR). Several injectable materials have been tried for this purpose. In this study, we tried to determine the efficacy of dextranomer/hyaluronic acid copolymer (Dx/HA) injection for the treatment of VUR in renal-transplant candidates. PATIENTS AND METHODS: A total of 21 transplant candidates (29 ureteral units; 13 females, 8 males) with a mean age of 20.2 years (range 14-26 years) underwent endoscopic correction of VUR with Dx/HA. Diagnosis of VUR was made by voiding cystourethrography. The efficacy of the treatment was assessed with voiding cystourethrography at 3 months and 1 year postoperatively. Renal transplantation with living related donor organs was performed in 11 of the 21 patients. RESULTS: Endoscopic treatment was performed without complication in all cases. Higher success rates were obtained in patients with low-grade reflux, the overall success rate in the series being 82.7%. The mean follow- up after renal transplantation was 21.8 months (range 5-45 months). In one patient, reflux recurred after renal transplantation and was treated successfully by a repeat Dx/HA injection. The urine cultures of all patients remained sterile. CONCLUSION: Transplant candidates with VUR can be treated with Dx/HA, which cured the majority of our patients after one or two treatments with few low side effects. Endoscopic subureteral injection of Dx/HA has become an alternative treatment for VUR in transplant candidates. Long-term results are needed before making a final statement about its value.  相似文献   
102.
The purpose of this study was to evaluate the impact of the Glasgow Coma Scale (GCS), Acute Physiology and Chronic Health Evaluation (APACHE) II and Simplified Acute Physiology Score (SAPS) II scoring systems for organophosphate poisoning (OPP) in an intensive care unit (ICU). The following data were collected on all consecutive patients who were admitted to the ICU between June 1999 and December 2004. Demographic data, GCS, APACHE II and SAPS II scoring systems were recorded. Predicted mortality was calculated using original regression formulas. Standardized mortality ratio (SMR) was computed with 95% confidence intervals (CI). The sensitivity and specificity for each scoring system were evaluated by calculating the Area Under the Receiver Operating Characteristic Curves. The actual mortality in OPP was 21.9%. Predicted mortality by all systems was not significantly different from actual mortality [SMR and 95% CI for GCS: 1.00 (0.65 1.35), APACHE II: 0.87 (0.54-1.03), SAPS II: 1.40 (0.98-1.82)]. The area under the ROC curve for APACHE II is largest, but there is no statistically significant difference when compared with SAPS II and GCS (GCS 0.900 +/- 0.059, APACHE II 0.929 +/- 0.045 and SAPS II 0.891 +/- 0.057). In our ICU group of patients, in predicting the mortality rates in OPP, the three scoring systems, which are GCS, APACHE II and SAPS II, had similar impacts; however, GCS system has superiority over the other systems in being easy to perform, and not requiring complex physiologic parameters and laboratory methods.  相似文献   
103.
An inflammatory myofibroblastic tumor is an uncommon benign tumor located in various organs that can be misdiagnosed as a malignant neoplasm. We herein present two patients with ileocecal inflammatory myofibroblastic tumors. An abdominal mass was detected in a 13-year-old girl and a 15-year-old boy who presented with paleness, fatigue, intermittent fever, and night sweating. The radiological findings confirmed a mass originating from the ileocecal region. The presumptive diagnosis was Burkitt’s lymphoma. The histopathological diagnosis was inflammatory myofibroblastic tumor. After a surgical resection, all systemic symptoms rapidly resolved. Inflammatory myofibroblastic tumor is a rare pseudosarcomatous clinical and pathological entity. Although this tumor is more commonly reported in the lung, it can be detected in extrapulmonary sites, including the mesentery. Because the choice of treatment for this tumor is conservative surgery, an accurate preoperative analysis is important to avoid any unnecessary aggressive surgical intervention or other therapeutic approaches.  相似文献   
104.
Kanbay M  Gur G  Akcay S  Yilmaz U 《Respiratory medicine》2005,99(10):1213-1216
AIM: A high rate of seropositivity for antibodies against Helicobacter pylori has been found in many extra-gastrointestinal diseases. In addition, it has been reported that the risk of chronic bronchitis may be increased in subjects infected with H. pylori. This study was designed to determine the H. pylori seroprevalence in patients with and without chronic bronchitis. MATERIALS AND METHODS: This study enrolled 68 patients with chronic bronchitis (40 men and 28 women, aged 50.5+/-16.2 years (mean+/-standard deviation) and 95 control subjects (60 men and 35 women, aged 51.8+/-15.9 years) matched for age and sex. An enzyme-linked immunosorbent assay immunoglobulin (Ig) G test for H. pylori diagnosis was performed on all enrolled subjects (those with chronic bronchitis and controls). RESULTS: Forty-five of 68 patients with chronic bronchitis (66.1%) and 48 of 95 subjects in the control group (57.7%) tested positive for H. pylori (P=0.008). Rates of H. pylori infection are higher in patients with chronic bronchitis than in the control group. CONCLUSION: The main conclusion of this study is that H. pylori infection is associated with an increased prevalence chronic bronchitis. Further studies should be planned to understand the potential pathogenetic mechanisms that might underlie this association.  相似文献   
105.
Angiolipoma of the neck: a case report   总被引:1,自引:0,他引:1  
Angiolipomas of the neck are extremely rare; to our knowledge, only 2 cases have been previously reported. We report a new case, which occurred in a 28-year-old woman. The mass was totally resected, and the patient showed no recurrence at the 18-month follow-up.  相似文献   
106.
OBJECTIVE: To evaluate the correlation between adenoidal-nasopharyngeal ratio (AN ratio) and tympanogram in children. STUDY DESIGN: A prospective clinical study from June 2002 to May 2003. METHOD: A total of 64 children, aged 6-9 years who presented with nasal obstruction, snoring, mouth breathing, and hyponasal speech were examined and AN ratio was calculated by using the lateral neck radiograms and compared with the tympanometric values. The relationship between AN ratio and middle-ear pressure was evaluated, regarding the AN ratio of 0.71. The chi-square test was used to analyze the correlation between AN ratio and middle ear pressures and Wilcoxon test was used to compare the changes between the mean AN ratio values, and mean middle ear pressures (including A and C type tympanograms) before and after medical therapy. RESULTS: Middle-ear effusions and C type tympanograms in impedance audiometry were both related to eustachian tube dysfunction resulting from enlargement of the adenoids with AN ratios higher than 0.71. Middle ear pressures were found lower in children with AN ratio greater than 0.71 than in children AN ratio less than 0.71 and the difference was highly significant (p<0.001). Although medical treatment of large adenoids was rather effective to shrink the adenoid tissue (p<0.001), it did not cause a statistically significant change in tympanometric values (p>0.05). CONCLUSIONS: Antibiotherapy is effective in reducing adenoid size without signs and symptoms of infection. The reduction of the adenoids in size after 3 weeks of antibiotherapy has an positive effect on recovery of eustachian tube function but is not sufficient in patients with middle ear effusion. Early ventilation tube insertion may be an alternative therapy for the middle ear effusions not improving by 3 weeks medical therapy.  相似文献   
107.
108.
Effects of erythropoietin on hyperoxic lung injury in neonatal rats   总被引:3,自引:0,他引:3  
Pulmonary oxygen toxicity is believed to play a prominent role in the lung injury that leads to the development of bronchopulmonary dysplasia (BPD). To determine whether human recombinant erythropoietin (rhEPO) treatment reduces the risk of developing BPD, we investigated the effect of rhEPO treatment on the histopathologic changes seen in hyperoxia-induced lung injury of BPD. Twenty-five rat pups were divided into four groups: air-exposed control group (n = 5), hyperoxia-exposed placebo group (n = 7), hyperoxia-exposed rhEPO-treated group (n = 6), and air-exposed rhEPO-treated group (n = 7). Measurement of alveolar surface area, quantification of secondary crest formation, microvessel count, evaluation of alveolar septal fibrosis, and smooth muscle actin immunostaining were performed to assess hyperoxia-induced changes in lung morphology. Treatment of hyperoxia-exposed animals with rhEPO resulted in a significant increase in the mean alveolar area, number of secondary crests formed, and the microvessel count in comparison with hyperoxia-exposed placebo-treated animals. There was significantly less fibrosis in rhEPO-treated animals. However, treatment of hyperoxia-exposed animals with rhEPO did not result in a significant change in smooth muscle content compared with hyperoxia-exposed placebo treated animals. Our results suggest treatment with rhEPO during hyperoxia exposure is associated with improved alveolar structure, enhanced vascularity, and decreased fibrosis. Therefore, we conclude that treatment of preterm infants with EPO might reduce the risk of developing BPD.  相似文献   
109.
OBJECTIVES: The aim of this study was to evaluate the significance of p53 expression and proliferative activity of glandular epithelium and intestinal metaplasia in Helicobacter pylori associated gastritis of pediatric patients. METHODS: The study included endoscopic gastric biopsies of 54 children with dyspeptic complaints. Immunohistochemistry was performed for evaluation of p53 expression and Ki-67 labeling index, an indicator of proliferative activity. Grading of H. pylori density, intestinal metaplasia and inflammatory cell infiltration were performed in histologic tissue sections stained with hematoxylin-eosin, Giemsa and Alcian-blue. RESULTS: Of 54 children, 35 (64%) were infected by H. pylori. Positive immunostaining for p53 was observed in 11 of 54 cases (20.4%). H. pylori infection was found in 10 (91%) of the p53-positive patients. There was a positive correlation between H. pylori density and Ki-67 labeling index in H. pylori infected children. H. pylori density, Ki-67 labeling index and inflammatory cell infiltration in the p53-positive group were significantly higher than in the p53-negative group. Although intestinal metaplasia was more common in H. pylori infected children (n = 11; 31.4%), there was no difference in the rate of intestinal metaplasia between the p53-positive and p53-negative groups. CONCLUSIONS: The present study shows that p53 mutations and higher proliferative activity of glandular epithelium may be related to H. pylori associated gastritis in children. Because p53 mutation does not appear to be associated with intestinal metaplasia, a precursor for gastric cancer in adults, we think that H.pylori associated p53 alterations do not initiate and promote gastric cancer that may occur in adulthood.  相似文献   
110.
Untreated patent ductus arteriosus carries a higher risk in adults than in children, especially when the defect is large (>4.0 mm in diameter), short, or friable. Therefore, various technical precautions have been suggested for application during surgical closure of a patent ductus arteriosus in an adult. We report the case of a 47-year-old woman with a patent ductus arteriosus who underwent transpulmonary surgical closure of the ductus under hypothermic total circulatory arrest. We discuss the technique in light of the current English-language medical 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