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   908篇
  免费   69篇
  国内免费   1篇
耳鼻咽喉   8篇
儿科学   50篇
妇产科学   2篇
基础医学   73篇
口腔科学   135篇
临床医学   66篇
内科学   200篇
皮肤病学   4篇
神经病学   85篇
特种医学   43篇
外科学   127篇
综合类   1篇
预防医学   82篇
眼科学   3篇
药学   78篇
肿瘤学   21篇
  2023年   6篇
  2022年   3篇
  2021年   15篇
  2020年   19篇
  2019年   16篇
  2018年   31篇
  2017年   23篇
  2016年   26篇
  2015年   32篇
  2014年   67篇
  2013年   66篇
  2012年   79篇
  2011年   95篇
  2010年   69篇
  2009年   54篇
  2008年   66篇
  2007年   67篇
  2006年   52篇
  2005年   52篇
  2004年   36篇
  2003年   30篇
  2002年   25篇
  2001年   2篇
  2000年   1篇
  1999年   3篇
  1998年   8篇
  1997年   2篇
  1996年   5篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1992年   2篇
  1991年   1篇
  1990年   6篇
  1989年   3篇
  1987年   1篇
  1986年   1篇
  1983年   2篇
  1981年   2篇
  1980年   1篇
  1979年   1篇
  1969年   1篇
  1965年   1篇
  1963年   2篇
排序方式: 共有978条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Alcohol is mainly consumed in social settings, in which people often adapt their drinking behaviour to that of others, also called imitation of drinking. Yet, it remains unclear what drives this drinking in a social setting. In this study, we expected to see stronger brain and behavioural responses to social compared to non‐social alcohol cues, and these responses to be associated with drinking in a social setting. The sample consisted of 153 beer‐drinking males, aged 18–25 years. Brain responses to social alcohol cues were measured during an alcohol cue‐exposure task performed in an fMRI scanner. Behavioural responses to social alcohol cues were measured using a stimulus‐response compatibility task, providing an index of approach bias towards these cues. Drinking in a social setting was measured in a laboratory mimicking a bar environment. Specific brain responses to social alcohol cues were observed in the bilateral superior temporal sulcus and the left inferior parietal lobe. There was no approach bias towards social alcohol cues specifically; however, we did find an approach bias towards alcohol (versus soda) cues in general. Brain responses and approach bias towards social alcohol cues were unrelated and not associated with actual drinking. Thus, we found no support for a relation between drinking in a social setting on the one hand, and brain cue‐reactivity or behavioural approach biases to social alcohol cues on the other hand. This suggests that, in contrast to our hypothesis, drinking in a social setting may not be driven by brain or behavioural responses to social alcohol cues.  相似文献   
5.
6.
7.
Some 90% of oral cancers consist of squamous cell carcinomas that arise from the oral mucosa. The remaining 10% of malignancies consist of malignant melanomas, carcinomas of the intraoral salivary glands, sarcomas of the soft tissues and the bones, malignant odontogenic tumors, non-Hodgkin's lymphomas and metastases from primary tumors located elsewhere in the body. These malignancies will be briefly reviewed and discussed. The emphasis is on diagnosis and management.  相似文献   
8.
BACKGROUND: The impact of smoking habits on periodontal conditions in older subjects is poorly studied. AIMS: To assess if a history of smoking is associated with chronic periodontitis and medical history in older subjects. MATERIAL AND METHODS: The medical and dental history was collected from 1084 subjects 60-75 years of age. Smoking history information was obtained from self-reports. Periodontal variables [clinical probing depth (PD)>/=5.0 mm, clinical attachment levels (CALs) >/=4.0 mm], and radiographic evidence of alveolar bone loss were assessed. RESULTS: 60.5% had never smoked (NS), 32.0% were former smokers (FS) (mean smoke years: 26.1 years, SD+/-13.1), and 7.5% were current smokers (CS) (mean smoke years 38.0 years, (SD+/-12.1). The proportional distribution of CAL >/=4.0 mm differed significantly by smoking status (NS and CS groups) (mean difference: 12.1%, 95% confidence interval (CI): 1.5-22.6, p<0.02). The Mantel-Haenszel common odds ratio between smoking status (CS+FS) and periodontitis (>20% bone loss) was 1.3 (p<0.09, 95% CI: 0.9-2.0) and changed to 1.8 (p<0.02, 95% CI: 1.3-2.7) with 30 years of smoking as cutoff. A weak correlation between number of years of smoking and CAL>/=4.0 mm was demonstrated (r(2) values 0.05 and 0.07) for FS and CS, respectively. Binary logistic forward (Wald) regression analysis demonstrated that the evidence of carotid calcification, current smoking status, gender (male), and the number of remaining teeth were explanatory to alveolar bone loss. CONCLUSIONS: A clinically significant impact on periodontal conditions may require 30 years of smoking or more. Tooth loss, radiographic evidence of carotid calcification, current smoking status, and male gender can predictably be associated with alveolar bone loss in older subjects.  相似文献   
9.
BACKGROUND/AIMS: Only limited information exists about the prevalence in children of pathogens associated with periodontitis. The aim of the present study was to determine by culture whether 8-11-year-old children carry Porphyromonas gingivalis, Prevotella intermedia, and/or P. nigrescens in samples from the gingiva and/or the buccal mucosa taken before, and after caries treatment and oral hygiene instruction. A second aim was to assess the proportion of subjects who had gram-negative anaerobes carrying the tet(Q) and erm(F) genes, suggesting antibiotic resistance to tetracycline or erythromycin. METHOD: A total of 150 children provided gingival and buccal swab bacterial samples that were cultured for P. gingivalis, P. intermedia, and P. nigrescens. The species was verified using DNA-DNA hybridization with species-specific probes made from the variable region of the 16S rRNA sequences. Antibiotic-resistant genes, tet(Q) and erm(F), were identified using specific DNA-DNA hybridization with specific DNA probes. RESULTS: A total of 116 isolates of black-pigmented bacteria were cultured from 47 (31%) of 150 children. Five isolates were identified as P. gingivalis, 29 as P. intermedia, 33 as P. nigrescens, and 49 as other species. In general, the bacteria were not culturable at more than one time period. We found that 55% of these 47 children harbored black pigmented bacteria that carried either one or both of the two antibiotic-resistant genes studied (tet(Q), and erm(F)). CONCLUSION: The present study demonstrated that children not exposed to regular dental treatment carry bacteria outside the gingival sulcus that have been associated with periodontitis, and that standard treatment procedures may not clear the presence of the putative pathogens. In addition, antibiotic-resistant genes are common in identifiable gram-negative anaerobes, including putative pathogens.  相似文献   
10.
BACKGROUND: An association between periodontitis and cardiovascular diseases has been suggested. AIMS: To study whether a combination of clinical variables in a functional risk diagram enhanced the ability to differentiate between subjects with or without an immediate history of acute myocardial infarction (AMI). MATERIAL AND METHODS: A functional periodontal pentagon risk diagram (PPRD) with five periodontal risk vectors was created. The surface of individual PPRDs was calculated using data from 88 subjects with recent AMI and 80 matched control subjects with no history of AMI. RESULTS: Age, gender, number of remaining teeth (mean value: 21.1 versus 21.6 teeth), smoking status, and pocket probing depth (PPD) distribution did not differ by group. Gingival recession was greater in control subjects (mean difference: 5.7, SD: +/- 1.9, p<0.01, 95% CI: 1.8-9.6). Bone loss > or = 4.0 mm was at all levels studied was significantly greater in subjects with AMI and bone loss > or = 50% (> or = 4 mm) was the best individual predictor of AMI (beta = 2.99, p < 0.000, 95% CI: 7.5-53.4). Only PPRD scores were associated with AMI status when factors not included in the PPRD were studied (beta = 22.1, SE: 5.9, p < 0.0001, 95% CI: 10.3-33.7). The best association between AMI status and study variables was the combination of > or = 4 mm of bone loss > or = 50%, proportion of bleeding on probing (%BOP), %PPDs > or = 6 mm, and tooth loss (Nagelkirke r2 = 0.46). CONCLUSIONS: The combination of five periodontal parameters in a PPRD added predictive value, suggesting that comprehensive data should be used in studies of associations between periodontitis and heart diseases. Radiographic evidence of bone loss was the best individual parameter.  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