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   1517篇
  免费   90篇
  国内免费   14篇
耳鼻咽喉   28篇
儿科学   32篇
妇产科学   60篇
基础医学   201篇
口腔科学   56篇
临床医学   138篇
内科学   349篇
皮肤病学   21篇
神经病学   79篇
特种医学   56篇
外科学   144篇
综合类   35篇
预防医学   82篇
眼科学   8篇
药学   149篇
中国医学   17篇
肿瘤学   166篇
  2023年   12篇
  2021年   28篇
  2020年   24篇
  2019年   34篇
  2018年   29篇
  2017年   32篇
  2016年   33篇
  2015年   59篇
  2014年   51篇
  2013年   43篇
  2012年   72篇
  2011年   99篇
  2010年   47篇
  2009年   32篇
  2008年   46篇
  2007年   71篇
  2006年   63篇
  2005年   56篇
  2004年   51篇
  2003年   46篇
  2002年   42篇
  2001年   35篇
  2000年   41篇
  1999年   37篇
  1997年   14篇
  1996年   11篇
  1994年   18篇
  1993年   16篇
  1992年   34篇
  1991年   23篇
  1990年   33篇
  1989年   54篇
  1988年   31篇
  1987年   34篇
  1986年   15篇
  1985年   33篇
  1984年   18篇
  1983年   17篇
  1981年   12篇
  1979年   15篇
  1978年   9篇
  1977年   10篇
  1976年   13篇
  1975年   14篇
  1974年   10篇
  1973年   9篇
  1972年   11篇
  1970年   9篇
  1969年   10篇
  1968年   10篇
排序方式: 共有1621条查询结果,搜索用时 62 毫秒
1.
2.
Abstract

Objective: Gastric distention and perforation are possible results in a preterm newborn with esophageal atresia and distal tracheoesophageal fistula, especially when there is a need for mechanical ventilatory support. The results of the reported cases treated with emergency thoracotomy and fistula ligation after gastrostomy are not very satisfactory. Sometimes simple temporary solutions can be useful for stabilization and allow safety for required surgical treatment for later.

Patient and methods: Two preterm newborns with esophageal atresia and distal tracheoesophageal fistula complicated by gastric perforation were reported.

Results: Both of the patients were initially treated with a simple peritoneal drainage and, then the definitive operations were performed without any problem in stabilized patients.

Conclusion: Performing fistula ligation or occlusion as an initial treatment in patients with impaired cardiac and respiratory functions may worsen the status of the patient. In such cases, it could be better to perform simple interventions first to facilitate subsequent treatments.  相似文献   
3.
Contamination by Staphylococcus aureus of the production environment of three small or medium-sized food-processing factories in Slovakia was investigated on the basis of sub-species molecular identification by multiple locus variable number of tandem repeats analysis (MLVA). On the basis of MLVA profiling, bacterial isolates were assigned to 31 groups. Data from repeated samplings over a period of 3 years facilitated to draw spatial and temporal maps of the contamination routes for individual factories, as well as identification of potential persistent strains. Information obtained by MLVA typing allowed to identify sources and routes of contamination and, subsequently, will allow to optimize the technical and sanitation measures to ensure hygiene.  相似文献   
4.
The aim of the present study was to evaluate whether it is possible to orthodontically move migrated teeth into infrabony defects augmented with a biomaterial. Three adult patients suffering from chronic periodontitis were treated. Each of the patients presented with an infrabony defect adjacent to a migrated maxillary central incisor. After cause-related therapy was completed, a surgical procedure was performed using the papilla preservation technique. The defects were filled with a collagen bovine bone mineral; after 2 weeks, an orthodontic device was activated using light, continuous forces. Orthodontic treatment time varied from 4 to 9 months; during this period, patients were enrolled in an oral hygiene recall program. At baseline and 6 months after the end of therapy, probing pocket depths (PPD) and clinical attachment levels (CAL) were assessed. In addition, the vertical and horizontal dimensions of the defects were measured on standardized radiographs. Residual mean PPD was 3.33 mm, with a mean reduction of 3.67 mm. Mean CAL gain was 4.67 mm. Radiologic vertical and horizontal bone fills were, on average, 3.17 mm and 2.0 mm, respectively. The present case series shows the effectiveness of a combined periodontic-orthodontic approach for the treatment of infrabony defects. Reduction of PPD to physiologic values, CAL gain, and radiologic defect resolution were obtained. No detrimental effects from the orthodontic movement were observed on the augmentation material.  相似文献   
5.
6.
BACKGROUND: In cases of advanced periodontal disease with a pathologic flaring of frontal teeth, a combined periodontic-orthodontic therapy may be a reliable approach in order to solve both functional and esthetic problems. The aim of the present study was to evaluate the periodontal tissue alterations following periodontal surgery and orthodontic intrusion in migrated upper central incisors with intrabony defects. METHODS: Ten patients with advanced periodontal disease and an extruded maxillary central incisor infrabony defect at its mesial aspect and probing depth (PD) > or = 6 mm were included in the present study. At baseline, PD and clinical attachment level (CAL) were measured. The vertical and horizontal dimensions of the defects were assessed on standardized radiographs. Seven to 10 days after surgery the active orthodontic treatment started using the segmented arch technique, in order to intrude and move the teeth into the defects. Maintenance therapy was performed every 2 to 3 months until the orthodontic treatment was completed. RESULTS: At the end of treatment, mean PD reduction was 4.35 mm, with a residual mean PD of 2.80 mm. Mean CAL gain was 5.50 mm. The mean radiological vertical and horizontal bone fills were, respectively, 1.35 mm and 1.40 mm. All differences were of statistical significance (P<0.001). CONCLUSION: The present study showed that the combined orthodontic and periodontic therapy performed resulted in the realignment of extruded teeth with infrabony defects, obtaining a significant probing depth reduction, clinical attachment gain, and radiological bone fill.  相似文献   
7.
本实验通过ex vivo法测定PDMS和PDMS/PU两种材料表面接触血流前后的全血粘度(表观粘度),结果显示:两组材料组的表观粘度均高于阴性对照组(P<0.01),而两材料组之间的表观粘度则无显著差异(P>0.05).通过测定两种材料表面接触人体血液后血浆中β-TG含量,结果表明:两组材料的β-TG含量均明显高于阴性对照组(P<0.001),而两材料组间的β-TG含量则无差别(P>0.05).两组实验结果均表明,PDMS和PDMS/PU表面未具备良好的抗血栓性能.  相似文献   
8.
Cleaning and shaping the root canals play an important role to remove the organic debris within the endodontic system. The result, however, must be maintained over time through an effective root canal fillings preventing the entry of micro-organisms and tissutal fluid in the root canal system. Recently new materials have been introduced on the market, hence alternatives techniques for the root canals obturation have been developed and proposed. Even if cold lateral condensation is still considered the technique to refer to, there are numerous alternatives that use heat to achieve optimal adaptation of gutta-percha to the root canal space. The purpose of this work is to emphasize the positive aspect and points of weaknesses of different methods used for filling the root canals in order to allow the clinician to carry out choices as possible based on scientific evidence. Although many clinical trials still have not identified the superiority of one obturation technique over the others, the importance of this stage is objectively primary, so much that in the clinical practice we can notice an increasing success of endodontic treatment.  相似文献   
9.
10.
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