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   118748篇
  免费   47341篇
  国内免费   161篇
耳鼻咽喉   1899篇
儿科学   5621篇
妇产科学   1712篇
基础医学   21815篇
口腔科学   6000篇
临床医学   19212篇
内科学   31043篇
皮肤病学   8300篇
神经病学   17476篇
特种医学   3220篇
外科学   18475篇
综合类   644篇
一般理论   87篇
预防医学   9670篇
眼科学   1837篇
药学   8151篇
  2篇
中国医学   1077篇
肿瘤学   10009篇
  2023年   241篇
  2022年   315篇
  2021年   2168篇
  2020年   5540篇
  2019年   11588篇
  2018年   10991篇
  2017年   12065篇
  2016年   12750篇
  2015年   12784篇
  2014年   13095篇
  2013年   14291篇
  2012年   7188篇
  2011年   7318篇
  2010年   10648篇
  2009年   6731篇
  2008年   5115篇
  2007年   3923篇
  2006年   3980篇
  2005年   3556篇
  2004年   3476篇
  2003年   3331篇
  2002年   3303篇
  2001年   1215篇
  2000年   1059篇
  1999年   759篇
  1998年   577篇
  1997年   510篇
  1996年   461篇
  1995年   402篇
  1994年   400篇
  1993年   376篇
  1992年   378篇
  1991年   357篇
  1990年   329篇
  1989年   280篇
  1988年   312篇
  1987年   278篇
  1986年   244篇
  1985年   259篇
  1984年   284篇
  1983年   270篇
  1982年   332篇
  1981年   280篇
  1980年   256篇
  1979年   196篇
  1978年   181篇
  1977年   159篇
  1975年   142篇
  1974年   149篇
  1973年   142篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
131.
132.
133.
This study was designed to characterize a collection of 60 enteropathogenic Escherichia coli (EPEC) isolates from diarrheic feces of patients in the Ribeirão Preto metropolitan area regarding different phenotypic and molecular features. We examined antibiotic resistance profiles, occurrence of virulence factors‐encoding genes, intimin subtypes and the correlation of serotypes among typical (tEPEC) and atypical (aEPEC) EPEC isolates. The results demonstrated that atypical EPEC was more heterogeneous than typical EPEC concerning the characteristics investigated and 45.2% do not belong to classical EPEC serogroups. Intimin subtype β was the most frequent among the EPEC isolates (46.7%), being detected in both tEPEC and aEPEC. The majority of aEPEC isolates presented localized adherence‐like (LAL) pattern to HEp‐2 cells, although aEPEC isolates displaying diffuse adherence (DA) or non‐adherent were also detected. High prevalence of antimicrobial resistance was found for ampicillin, cephalothin, sulfonamide and tetracycline. In general, tEPEC isolates were more resistant to the antimicrobials tested than aEPEC isolates.  相似文献   
134.
Sometimes the clinical differentiation between verruca plana (VP) and VP‐like seborrheic keratosis (SK) could be challenged. However, there have been no studies on this issue to date. The aim of this study was to elucidate clinical and dermoscopic differences between these two diseases, and also to suggest a diagnostic algorithm of VP and VP‐like SK without skin biopsy. The patients who had lesions clinically considered as VP or VP‐like SK were the target of our study. We took clinical and dermoscopic photos with informed consent and conducted a questionnaire. All patients had their diagnoses confirmed by biopsy. Thirty‐three patients were enrolled in our study. Seventeen patients were finally diagnosed with VP (51.5%) and 16 patients with VP‐like SK (48.5%). In clinical findings, VP‐like SK showed significantly more scattered distribution than VP (P = 0.039), which exhibited more clustered or grouped distribution (P = 0.039). In dermoscopic findings, brain‐like appearance was more commonly observed in VP‐like SK (P = 0.003) whereas VP showed more red dots or globular vessels (P = 0.017) and even‐colored light brown to yellow patch (P < 0.001). Sex, onset age, the size of each lesion, location, color and shape showed no significant differences between them (P > 0.05). Based on our results, we suggest a diagnostic algorithm using Koebner's phenomenon, dermoscopic findings, distribution of each lesion and biopsy for multiple VP‐like lesions in adults, and we think it will be a very useful diagnostic tool in daily clinical dermatological practice.  相似文献   
135.
136.
137.
138.
139.
140.
Idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) is a rare and poorly understood ischemic colitis that occurs in the rectosigmoid colon of predominantly young, previously healthy, male patients. A 76‐year‐old Japanese man presented to our hospital with a 1‐year history of worsening diarrhea, lower abdominal pain, and weight loss (−6 kg). Laboratory evaluation revealed white blood cell count of 13 200/μL, C‐reactive protein level of 2.0 mg/dL (normal range, 0.0–0.3), and negative results for stool culture (including Clostridium difficile). Colonoscopy showed circumferential and edematous narrowing of the sigmoid colon with deep longitude ulceration. Biopsy was done and examination of the specimen demonstrated no specific ischemia. The patient was treated with bowel rest, antibiotics, and i.v. fluids; however, his symptoms worsened. Finally, sigmoidectomy was carried out. Histological examination demonstrated significant myointimal hyperplasia of mesenteric veins leading to thickening and stenosis of the venous lumen. Therefore, the final diagnosis was IMHMV. Three months following sigmoidectomy, he was asymptomatic.  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