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   103998篇
  免费   16474篇
  国内免费   2422篇
耳鼻咽喉   2112篇
儿科学   2183篇
妇产科学   1938篇
基础医学   3920篇
口腔科学   4321篇
临床医学   23040篇
内科学   21873篇
皮肤病学   2702篇
神经病学   10548篇
特种医学   3478篇
外国民族医学   13篇
外科学   16214篇
综合类   3609篇
现状与发展   34篇
一般理论   1篇
预防医学   11867篇
眼科学   2205篇
药学   2883篇
  22篇
中国医学   1137篇
肿瘤学   8794篇
  2024年   933篇
  2023年   4586篇
  2022年   1869篇
  2021年   3101篇
  2020年   4991篇
  2019年   2236篇
  2018年   6094篇
  2017年   6304篇
  2016年   6868篇
  2015年   7173篇
  2014年   9302篇
  2013年   10435篇
  2012年   4070篇
  2011年   4043篇
  2010年   6331篇
  2009年   7940篇
  2008年   3603篇
  2007年   2737篇
  2006年   3634篇
  2005年   2506篇
  2004年   1605篇
  2003年   1460篇
  2002年   1223篇
  2001年   1892篇
  2000年   1399篇
  1999年   1916篇
  1998年   1968篇
  1997年   1864篇
  1996年   1824篇
  1995年   1593篇
  1994年   1101篇
  1993年   845篇
  1992年   748篇
  1991年   648篇
  1990年   522篇
  1989年   526篇
  1988年   491篇
  1987年   375篇
  1986年   321篇
  1985年   297篇
  1984年   218篇
  1983年   241篇
  1982年   183篇
  1981年   158篇
  1980年   91篇
  1979年   63篇
  1978年   89篇
  1977年   94篇
  1976年   75篇
  1972年   54篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
A case of mandibulofacial dysostosis (Treacher Collins syndrome) is presented. Clinical features and skull radiographs revealed typical anomalies associated with the syndrome. Cleft of the soft palate and unerupted multiple supernumerary teeth were present in this case. No haematological, biochemical or immunological abnormalities could be detected in the patient. Pedigree analysis showed an autosomal dominant mode of transmission of the disease. Chromosomal studies did not reveal any structural or numerical discrepancies.  相似文献   
12.
The Validity of Self-reported Oral Health Status in the Elderly   总被引:4,自引:0,他引:4  
The validity of self-reported number of teeth was assessed in a random sample of 50 individuals aged 70+ by comparing self-reports in a telephone interview with results of a subsequent in-home examination by a dentist. There were no significant differences between self-report and examination data, nor was there any systematic under- or over-counting of teeth as the actual number of teeth increased. These data support the validity of self-reported dentition.  相似文献   
13.
The purpose of this study was to evaluate the oral health status, treatment needs, and dental care utilization patterns of a Native American population aged 65-74 years. A random sample of 688 individuals was chosen and approached regarding participation in the study. Data were gathered through an interviewer-administered questionnaire and an oral examination. A total of 204 individuals completed all aspects of the study. Only one participant had all 28 natural teeth, while 58.3 percent were totally endentulous. Of the 85 dentate participants, almost 53 percent required at least one extraction. The average number of required extractions in the dentate subjects was three. Although 94 percent of the sample stated they had a usual source of dental care, 40.7 percent had not visited a dentist within the last five years. Multiple regression analyses were used to determine the factors associated with total number of teeth present among the dentate participants. Years of education and time since last dental visit were the two significant predictors (P less than .05) of number of teeth present. The higher the level of education, the greater the number of teeth in later life. The number of teeth present was inversely related to years since dental treatment. Compared to the results of the National Survey of Oral Health in US Employed Adults and Seniors, this Native American sample had a higher prevalence of endentulism and utilized dental services less often than a comparable age group in the US population as a whole.  相似文献   
14.
Kazuya Yoshida  DDS  PhD    Akira Takagi  CDT    Yoichi Tsuboi  DDS  PhD    & Kazuhisa Bessho  DDS  PhD 《Journal of prosthodontics》2008,17(3):219-222
Maintenance of healthy periimplant soft tissue is a significant problem for orbital prosthesis wearers. Two female patients with orbital defects after malignant tumor resection were treated using custom‐made retentive components of an individual magnet for an Epitec System orbital prosthesis. Freestanding hygienic retentive components for an individual magnet were fabricated. An abutment replica was trimmed and modified, and using pattern resin, a magnetic keeper was cast and soldered to the abutment. The patients could maintain good hygiene and healthy periimplant soft tissue. This type of freestanding retentive component may be advantageous for the hygiene maintenance of periimplant soft tissue.  相似文献   
15.
This paper describes the periodontal disease experience of a community-dwelling population aged 50 years and older, living in four communities in Ontario, Canada. The periodontal status of this population was assessed using attachment loss and the extent and severity index. Attachment loss was measured at two sites on each tooth using a pressure-sensitive periodontal probe. Complete periodontal data were obtained on 624 subjects. The mean number of sites per subject was 37.9. In line with recent US studies, the diagnostic threshold for a diseased or previously diseased site was set at 2 mm of loss. The overall mean attachment loss was 2.95 mm, with 19.7 percent of subjects having an overall mean attachment loss of 4.00 mm or more. The proportion of sites examined with loss of attachment of 2 mm or more was 77 percent. The severity of disease, defined as the average distance between the base of the sulcus or pocket and a point 1.00 mm apical to the cemento-enamel junction in sites with loss of 2 mm or more was 2.44 mm. These data indicate that the extent and severity of disease in this population were greater than that reported by some recent studies in the US. Taken together, the results of these studies suggest that there is some variation in the periodontal disease experience of population subgroups across North America.  相似文献   
16.
Terminology of facial morphology in the vertical dimension   总被引:1,自引:0,他引:1  
Consideration of facial type plays an important role in the formulation of an orthodontic treatment plan and prognosis of treatment. Of particular importance is the vertical relationship, that is, whether an individual is long-faced (dolichofacial), or short-faced (brachyfacial). The vertical facial type provides a clue regarding the growth direction of the facial complex, and should be used with an anteroposterior classification to describe a patient's face. The potential for confusion in communicating vertical facial types exists due to the nature of the terminology in use. For example, the term dolichoprosopic as used in the Bimler analysis has an opposite meaning to the term dolichofacial. It would seem prudent that if such terminology is to be employed there should be some attempt at standardization, and at least an appreciation of the derivations of the terms, and their differences.  相似文献   
17.
Drug-induced palatal pigmentation   总被引:1,自引:0,他引:1  
A bstract — Palatal pigmentations are rare in children. Four cases of palatal pigmentation associated with the prescribed use of the drug amodiaquine are tabulated and two are reported in detail. The wider clinical application of this anti-malarial drug and the potential for drug-induced palatal pigmentations are of dental interest. The pigmentation persists for an indefinite period after withdrawal of the drug.  相似文献   
18.
19.
Purpose: To investigate photoelastically the difference in load distribution of dental implants with different implant neck designs in intact and compromised bone. Materials and Methods: Composite photoelastic models were fabricated using two different resins to simulate trabecular bone and a 1‐mm thick layer of cortical bone. The following parallel‐sided, threaded implants were centrally located in individual models representing intact and compromised cortical bone: Straumann (4.1‐mm diameter × 12‐mm length), AstraTech (4.0‐mm diameter × 13‐mm length), and 3i (3.75‐mm diameter × 13‐mm length). The compromised cortical bone condition was simulated by contaminating a 1‐mm neck portion with Vaseline to impair the implant–resin interface. Vertical and oblique static loads were applied on the abutments, and the resulting stresses were monitored photoelastically and recorded photograhphically. Results: For the fully intact condition, the highest stresses were observed around the crest and apical region for all implant designs under vertical and inclined loads. There were no appreciable differences in magnitude or distribution between implant types. With compromised cortical bone, for all designs and load directions, higher stresses in the supporting structures were observed. Increased stresses were noted especially at the cortical bone–trabecular bone interface. Somewhat lower stress levels were observed with the 3i implant. Conclusions: The condition of implant–cortical bone contact has considerable influence on stress distribution. A compromised cortical bone condition caused higher level stresses for all implant designs tested.  相似文献   
20.
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