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   82698篇
  免费   44928篇
  国内免费   91篇
耳鼻咽喉   1568篇
儿科学   4428篇
妇产科学   932篇
基础医学   16708篇
口腔科学   5410篇
临床医学   13158篇
内科学   24884篇
皮肤病学   7599篇
神经病学   13952篇
特种医学   2555篇
外国民族医学   3篇
外科学   15252篇
综合类   261篇
一般理论   25篇
预防医学   4602篇
眼科学   1345篇
药学   5968篇
  1篇
中国医学   1063篇
肿瘤学   8003篇
  2023年   83篇
  2022年   93篇
  2021年   1556篇
  2020年   5178篇
  2019年   10975篇
  2018年   10263篇
  2017年   11574篇
  2016年   12249篇
  2015年   12121篇
  2014年   12081篇
  2013年   12642篇
  2012年   4710篇
  2011年   4618篇
  2010年   9215篇
  2009年   5532篇
  2008年   2527篇
  2007年   1431篇
  2006年   1368篇
  2005年   1172篇
  2004年   1166篇
  2003年   1097篇
  2002年   1197篇
  2001年   1101篇
  2000年   1018篇
  1999年   578篇
  1998年   129篇
  1997年   127篇
  1996年   97篇
  1995年   80篇
  1994年   89篇
  1993年   72篇
  1992年   179篇
  1991年   166篇
  1990年   132篇
  1989年   154篇
  1988年   82篇
  1987年   127篇
  1986年   89篇
  1985年   61篇
  1984年   78篇
  1983年   48篇
  1982年   30篇
  1981年   35篇
  1980年   32篇
  1979年   57篇
  1978年   29篇
  1976年   34篇
  1975年   24篇
  1974年   34篇
  1972年   32篇
排序方式: 共有10000条查询结果,搜索用时 460 毫秒
121.
122.
123.
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   
124.
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   
125.
126.
127.
128.
129.
130.
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