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   886篇
  免费   23篇
  国内免费   5篇
耳鼻咽喉   21篇
儿科学   43篇
妇产科学   16篇
基础医学   55篇
口腔科学   39篇
临床医学   60篇
内科学   234篇
皮肤病学   54篇
神经病学   11篇
特种医学   22篇
外科学   217篇
综合类   16篇
预防医学   34篇
眼科学   23篇
药学   40篇
中国医学   5篇
肿瘤学   24篇
  2023年   3篇
  2022年   7篇
  2021年   13篇
  2020年   8篇
  2019年   17篇
  2018年   13篇
  2017年   13篇
  2016年   19篇
  2015年   14篇
  2014年   25篇
  2013年   31篇
  2012年   64篇
  2011年   64篇
  2010年   33篇
  2009年   30篇
  2008年   83篇
  2007年   82篇
  2006年   72篇
  2005年   69篇
  2004年   79篇
  2003年   55篇
  2002年   44篇
  2001年   14篇
  2000年   18篇
  1999年   13篇
  1998年   4篇
  1997年   3篇
  1996年   1篇
  1995年   2篇
  1994年   2篇
  1992年   1篇
  1991年   4篇
  1990年   1篇
  1989年   4篇
  1988年   3篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1978年   1篇
  1970年   1篇
  1969年   1篇
排序方式: 共有914条查询结果,搜索用时 15 毫秒
1.
2.
Bilateral germ cell tumours of the testis are rare but a rise in their incidence is expected since with the new therapeutic possibilities a significant improvement in prognosis has been achieved even in patients with advanced metastatic spread. Of the 210 patients treated for malignent germ cell tumours at our Department, six (2.9%) developed a contralateral testicular tumour. All patients had metachronous tumours and the second tumours occurred after an interval ranging between 1 and 22 years. The epidemiology, histology, diagnosis, therapy and prognosis are discussed, and the significance of regular self-examination of the remaining testis in patients with testicular tumour is emphasized.  相似文献   
3.
A methodological approach to the classification of dermoscopy images.   总被引:2,自引:0,他引:2  
In this paper a methodological approach to the classification of pigmented skin lesions in dermoscopy images is presented. First, automatic border detection is performed to separate the lesion from the background skin. Shape features are then extracted from this border. For the extraction of color and texture related features, the image is divided into various clinically significant regions using the Euclidean distance transform. This feature data is fed into an optimization framework, which ranks the features using various feature selection algorithms and determines the optimal feature subset size according to the area under the ROC curve measure obtained from support vector machine classification. The issue of class imbalance is addressed using various sampling strategies, and the classifier generalization error is estimated using Monte Carlo cross validation. Experiments on a set of 564 images yielded a specificity of 92.34% and a sensitivity of 93.33%.  相似文献   
4.
Gynaecomastia in adolescents is a benign glandular proliferation of the male breast. Secondary causes of gynaecomastia in adolescents are relatively rare and may result from a wide variety of rare pathological conditions. Among these, klinefelter syndrome, complete androgen resistance, adrenal tumours and oestrogen-secreting testicular tumours, hypogonadism, hyperthyroidism, kidney disease and medications play a role in aetiology. The aim of our study is to review the demographic characteristics, hormone profile, aetiological characteristics of paediatric gynaecomastia patients admitted to a single center and to determine the frequency of pathological gynaecomastia. Forty-three male patients with gynaecomastia who applied to the paediatric endocrinology outpatient clinic were included in our study. Demographic characteristics, physical examination findings, hormone profile, breast ultrasonography and karyotype results of the patients were recorded. There were 43 male patients in our study. Thirty-six (83.7%) of the patients were pubertal gynaecomastia, 7 (16.2%) were pathological gynaecomastia. Three of the patients with pathological gynaecomastia were prepubertal gynaecomastia, 2 had klinefelter syndrome, 1 had hypergonadotropic hypogonadism after acute lymphoblastic leukaemia treatment and 1 had gynaecomastia after spirololactone use. Careful evaluation of patients with gynaecomastia is especially important in detecting pathological types. We reported the rare prepubertal gynaecomastia and klinefelter frequency in our study.  相似文献   
5.
Three thousand, five hundred and seventy-two laparoscopic procedures were analysed retrospectively from a single institution between 1996 and 2003. Operations were classified into four groups as diagnostic laparoscopy (386, 10.8%), minor (1092, 30.5%), major (1866, 52.4%) and advanced (228, 6.5%) laparoscopic procedures. Overall, 67 (1.88%) complications occurred. The complication rates were 1.81%, 1.37%, 1.82% and 4.82% in the respective groups. One death (0.03%) occurred due to aortic injury during insertion of the principal intraumbilical trocar. Complications during insertion of the Verres needle, principal and accessory trocars were noted in 25 cases (38.2%) and were comparable among the four groups. Intraoperative complications occurred in 32 patients (47.8%) encountered mainly in the major and advanced groups. Overall, acute postoperative complications occurred in 10 (14.9%) patients. Despite advanced technology and experience, complications during the installation phase of laparoscopy remain a major cause of significant morbidity and most operative complications occurred in advanced operative procedures. Complications associated with all types of laparoscopic procedures should not be underestimated.  相似文献   
6.
Purpose:To evaluate corneal densitometry (CD) of patients with arcus senilis (AS) and its association with the serum lipid markers.Methods:This is a cross-sectional, case-control study. The AS diagnosis was made clinically. Forty-five eyes of 45 patients with AS and 38 eyes of 38 age-matched control subjects with no noticeable AS were enrolled in the study. All participants underwent detailed ophthalmologic examination along with corneal Scheimpflug imaging with CD measurement. The evaluated serum lipid markers of the participants included total cholesterol, triglyceride, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and very-low-density lipoprotein (VLDL). The Spearman correlation analysis was used to correlate the serum lipid values and the CD. P < 0.05 was defined as statistically significant.Results:The male to female ratio was 26/19 and 14/24 in the study and control groups, respectively (P = 0.057). The mean age was 59.56 ± 8.7 and 56.47 ± 8.6 years in the study and control groups, respectively (P = 0.117). The mean total CD values in the zones extending from 2 to 12 mm were higher in the study group than in the control group (P < 0.001). The serum HDL level was found to be significantly decreased in the study group compared to the control group (P = 0.048 and Z = −1.976). There was a significant positive correlation between the serum triglyceride level and the CD value of the outermost zone (10–12 mm) (r = 0.334 and P = 0.025).Conclusion:The CD of patients with AS was found to increase not only in the peripheral zone but also in the cornea’s paracentral zone compared to the healthy controls. The serum triglyceride level should give an insight into the intensity of arcus senilis. The serum HDL levels were decreased in patients with AS.  相似文献   
7.
Background : Reduced left lung perfusion has been described after transcatheter closure of the patent ductus arteriosus (PDA) with several prostheses. Although the Amplatzer ductal occluder (ADO) device is currently the most widely used occluder for closure of large‐sized PDAs, the potential consequences of flow distribution to the lungs of this device have not been completely clarified. We evaluated lung perfusion following occlusion of PDA with the ADO device. Methods : Forty‐seven patients underwent successful transcatheter PDA occlusion using the ADO device were included in this study. Lung perfusion scans were performed 6 months after the procedure. Results : Decreased perfusion to the left lung (defined as < 40% of total lung flow) was observed in 17 patients (36%), 5 of whom were low‐weight symptomatic infants. Ductal ampulla length was significantly shorter and minimal ductal diameter to ampulla diameter ratio was significantly higher in patients with decreased left lung perfusion and correlated well with left lung perfusion values (r = 0.516 and r = ?0.501, respectively). A cut‐off value of ≤5.8 mm for the ductal ampulla length and ≥1.9 for ampulla diameter to ampulla length ratio showed high sensitivity and specificity for reduced lung perfusion. Conclusions : The incidence of abnormal left lung perfusion is high 6 months after transcatheter closure of PDA with the ADO, more likely in the low weight symptomatic infants and in patients with a short duct or a relatively shallow duct having abrupt narrowing of a large ampulla. © 2010 Wiley‐Liss, Inc.  相似文献   
8.
This study aimed to analyze NKX3.1 expression in tissue samples of benign prostate hyperplasia (BPH) and in three different prostate cancer categories. The correlation of NKX3.1 expression with clinical and pathologic features of patients having undergone radical prostatectomy also was investigated. NKX3.1 expression was determined in tissue samples obtained from four different histopathological categories: (1) from patients treated with transurethral prostatectomy for BPH (n = 26), (2) localized prostate cancer patients subjected to radical prostatectomy (n = 38), (3) biopsy samples from prostate cancer patients who were metastatic at the initial admission (n = 10), and (4) tissue samples of prostate cancer patients administered antiandrogens, but who had undergone transurethral prostatectomy for infravesical obstruction (n = 11). Standard immunohistochemical staining was performed using an antiserum raised against recombinant human NKX3.1. Staining was seen in all categories of prostatic tissues. Immunohistochemistry staining scores were lower in prostate cancer patients. The staining scores were significantly higher in patients with BPH compared to metastatic or localized prostate cancer patients. Staining scores of patients with BPH and of those under antiandrogen therapy were similar. No significant correlation was found between NKX3.1 expression and tumor volume, Gleason sum scores, the presence of extraprostatic extension, tumor stage, or serum PSA. NKX3.1 expression is significantly decreased in prostate cancer patients when compared to BPH. However, the decline of NKX3.1 expression was not correlated with prostate cancer progression and was not associated with advanced stage. Thus, NKX3.1 expression is not a clinically valuable prognostic factor.  相似文献   
9.
BACKGROUND: Bioabsorbable membranes have been successfully used for guided tissue regeneration (GTR) and local delivery systems because they are biocompatible and do not require second surgery for removal. Several studies have demonstrated that metronidazole, when applied topically, produced immediate effects on microbiological and clinical parameters, most notably a reduction in probing depth and loss of attachment. The purpose of this study was to evaluate the regenerative potential of a metronidazole-loaded biodegradable (polylactide/glycolide) (PLGA) GTR membrane in dogs. METHODS: Six male adult dogs with 36 created osseous defects were enrolled. Bilateral dehiscence type defects in 5 mm diameter were created at buccal aspect of the alveolar bone in maxillary premolar teeth. After full thickness flap elevation, exposed root surfaces were thoroughly planed. In the experimental sites, PLGA membranes with or without metronidazole were fitted and placed over the defects. On the control defects only root planing was performed. Gingival flaps were replaced slightly coronal to the cemento-enamel junction. Animals were sacrificed at 60 days. The histometric analysis was evaluated with the following parameters: defect height (DH), apical extension of junctional epithelium (AEJE), new cementum height (NCH), new bone height (NBH), and new gingival connective tissue height (NCTH). RESULTS: Postoperative clinical healing was similar in the 3 groups. There were no statistically significant differences between the 2 experimental groups in any parameters. Statistically significant differences were observed for AEJE, NCH, NBH, and NCTH in experimental groups when compared with the controls. Statistically significantly greater NCH, NBH, and NCTH were seen in the experimental groups than the controls and control defects showed longer AEJE than the experimental defects. CONCLUSIONS: These results suggest that PLGA membranes with and without metronidazole may have a beneficial effect on periodontal regeneration.  相似文献   
10.
The risk of venous thromboembolism (VTE) increases in the presence of plasma cell dyscrasias. Monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) share an intrinsic increased risk of VTE. Treatment with thalidomide and lenalidomide further increases the incidence of VTE in certain MM patient subsets. The pathogenesis remains unclear, but probably involves several factors such as activation of procoagulant factors, acquired activated protein C resistance, and inflammation. In addition to general risk factors for VTE, such as older age, immobility, surgery, and inherited thrombophilia, there are some MM-specific and treatment-related factors that contribute to the increased risk. The risk for VTE is high under treatment with thalidomide or lenalidomide in combination with dexamethasone or multi-agent chemotherapy. We report 3 cases of MM with VTE with review of the literature. This review highlights the risk factors for VTE in MM and general, disease-specific and treatment-related mechanisms for thrombosis.  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