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   2944079篇
  免费   184695篇
  国内免费   7761篇
耳鼻咽喉   39118篇
儿科学   96221篇
妇产科学   79712篇
基础医学   421944篇
口腔科学   78184篇
临床医学   266746篇
内科学   573740篇
皮肤病学   69927篇
神经病学   234814篇
特种医学   112039篇
外国民族医学   774篇
外科学   436291篇
综合类   55885篇
现状与发展   6篇
一般理论   1044篇
预防医学   222385篇
眼科学   65190篇
药学   214724篇
  74篇
中国医学   5999篇
肿瘤学   161718篇
  2021年   22952篇
  2019年   23691篇
  2018年   32701篇
  2017年   25084篇
  2016年   29163篇
  2015年   32649篇
  2014年   44702篇
  2013年   66821篇
  2012年   89678篇
  2011年   95286篇
  2010年   57284篇
  2009年   54459篇
  2008年   88680篇
  2007年   94534篇
  2006年   95949篇
  2005年   91765篇
  2004年   88430篇
  2003年   85570篇
  2002年   82511篇
  2001年   140077篇
  2000年   143320篇
  1999年   120666篇
  1998年   34377篇
  1997年   30459篇
  1996年   30725篇
  1995年   29686篇
  1994年   27203篇
  1993年   25606篇
  1992年   93443篇
  1991年   91073篇
  1990年   88431篇
  1989年   85640篇
  1988年   78419篇
  1987年   76889篇
  1986年   71926篇
  1985年   68780篇
  1984年   51070篇
  1983年   43175篇
  1982年   25169篇
  1979年   45143篇
  1978年   31854篇
  1977年   26825篇
  1976年   25373篇
  1975年   27500篇
  1974年   32098篇
  1973年   30529篇
  1972年   28520篇
  1971年   26613篇
  1970年   24575篇
  1969年   23575篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
BACKGROUND: Tacrolimus, an immunosuppressive drug used in organ transplantation, has been reported not to induce gingival overgrowth. However, prevalence studies are limited, and the methods used for assessing gingival overgrowth varies among studies. OBJECTIVE: The purpose of this study was to evaluate the effects of up to 240 days of tacrolimus therapy on gingival tissues of rats. MATERIALS AND METHODS: Rats were treated for 60, 120, 180 and 240 days with daily subcutaneous injections of 1 mg/kg body weight of tacrolimus. After histological processing, the oral and connective tissue, volume densities of fibroblasts (Vf), collagen fibers (Vcf) and other structures (Vo) were assessed in the region of the lower first molar. RESULTS: After 60 and 120 days of treatment with tacrolimus, gingival overgrowth was not observed. The gingival epithelium, connective tissue, as well as the values for Vf, Vcf, and Vo were similar to those of the control rats (P>0.05). After 180 and 240 days of the treatment, gingival overgrowth was associated with a significant increase in the gingival epithelium and connective tissue as well as an increase in the Vf and Vcf (P<0.05). CONCLUSIONS: Within the limits of the experimental study, it may be concluded that the deleterious side effects of tacrolimus on the gingival tissues of rats may be time-related.  相似文献   
992.
Summary  The aim of this study was to explore the relationship between patterns of missing occlusal units (OUs) and oral health-related quality of life (OHRQoL) in subjects with the shortened dental arches (SDAs). Subjects with SDAs were recruited consecutively for 1 month from six university-based prosthodontic clinics. In total, 115 SDA subjects participated (mean age, 58·5 ± 10·0 years; 71% female). The location and number of missing teeth were examined and the number of missing OUs was calculated. To evaluate OHRQoL, the Japanese version of the Oral Health Impact Profile (OHIP-J) was administered and the summary score of OHIP-J was calculated. The SDA subjects were categorized depending upon the anterior-posterior lengths of the missing or remaining OUs. Regression analyses were performed to investigate the OHIP-J differences between groups of subjects with various anterior–posterior SDA lengths. The analyses revealed that subjects who only lost the second molar contact exhibited significantly better OHRQoL than those who lost more teeth [coefficient: 11·1, 95% confidence interval (CI): 2·8–19·2, P  = 0·02]. Furthermore a statistically significant group difference was observed between the groups with and without the first molar occlusal contact (coefficient: 12·8, 95% CI: 1·4 to 24·1, P  = 0·03). In conclusion, although our results are of exploratory nature and need validation, patterns of missing OUs are likely to be related to the OHRQoL impairment in SDA subjects with the presence of first molar contact having a particularly important role.  相似文献   
993.
994.

Background  

Squamous cells carcinoma is the most important malignant tumor with primary site in the oral cavity and, given the great exposure of mucosa and lips to the etiologic factors of this neoplasm, its incidence is high. Investigation of the prognostic determinants is significant for the expectations of treatment proposal and cure of the patient. The local immune response represented by peritumoral inflammatory infiltrate is a possible prognostic factor.  相似文献   
995.
996.
Hypodontia in combination with hyperdontia (hypohyperdontia) is a condition of mixed numeric variation in the human dentition. A comprehensive review on the hypohyperdontia literatures reported prevalence ranges from 0.002% to 3.1%. Our seven cases of hypohyperdontia involved both the maxillary and the mandibular arches. A traditional narrative review is included to describe the prevalence, etiology, and previously reported cases on hypohyperdontia. Furthermore, we opine that comprehensive clinical and radiographic examinations are essential for recognizing such rare dental anomalies. Judicious use of radiographs not only enhances the detection of hypohyperdontia, but also leads to changes in the course of management.  相似文献   
997.
998.
999.
The case of a 4-month-old male infant treated with combined surgery and chemotherapy for an aggressive recurrent melanotic neuroectodermal tumor of infancy (MNTI) on the top of the alveolar process of the mandible with a long-term follow-up is presented. Initial treatment comprised conservative local excision and curettage of the mandible. After several local recurrences and because radical surgical excision would give gross functional and aesthetic mutilation, finally complete, long-lasting remission was achieved with adjuvant chemotherapy, according to a neuroblastoma protocol (10-year follow-up). The reason for this protocol was because molecular genetic studies of this tumor showed loss of heterozygosity of chromosome 1p and gain of chromosome 7q analogue to neuroblastomas. A combination of surgery and chemotherapy should be the preferred treatment in case of a recurrence MNTI because optimal functional and aesthetic outcome.  相似文献   
1000.
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