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   2530篇
  免费   80篇
  国内免费   19篇
耳鼻咽喉   132篇
儿科学   123篇
妇产科学   99篇
基础医学   174篇
口腔科学   180篇
临床医学   178篇
内科学   493篇
皮肤病学   21篇
神经病学   173篇
特种医学   109篇
外科学   511篇
综合类   36篇
一般理论   1篇
预防医学   57篇
眼科学   117篇
药学   105篇
中国医学   30篇
肿瘤学   90篇
  2023年   16篇
  2022年   15篇
  2021年   37篇
  2020年   39篇
  2019年   41篇
  2018年   57篇
  2017年   43篇
  2016年   56篇
  2015年   71篇
  2014年   77篇
  2013年   125篇
  2012年   199篇
  2011年   197篇
  2010年   131篇
  2009年   120篇
  2008年   187篇
  2007年   185篇
  2006年   192篇
  2005年   178篇
  2004年   185篇
  2003年   181篇
  2002年   115篇
  2001年   44篇
  2000年   28篇
  1999年   14篇
  1998年   14篇
  1997年   12篇
  1996年   11篇
  1995年   9篇
  1994年   8篇
  1993年   6篇
  1992年   4篇
  1991年   4篇
  1990年   7篇
  1989年   2篇
  1985年   2篇
  1984年   3篇
  1983年   3篇
  1982年   2篇
  1981年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1974年   1篇
  1962年   1篇
  1961年   1篇
  1959年   1篇
排序方式: 共有2629条查询结果,搜索用时 31 毫秒
1.
2.

Purpose

To evaluate the effect of metabolic parameters of pretreatment primary tumor and regional lymph nodes with F-18-FDG PET/CT compared with MRI findings for the prognostic value and disease-free survival (DFS) in locally advanced cervical cancer.

Material and Methods

From 2011 to 2016, 112 patients with a diagnosis of cervical cancer stages IB2-IVA treated with concomitant chemoradiation therapy with 3D intracavitary brachytherapy were analyzed. From this group, 50 patients who underwent pretreatment and posttreatment FDG PET/CT and MRI were enrolled. LRFFS, DFS, and overall survival were analyzed in comparison with FDG PET/CT and MRI data. Relationship between SUVmax data and DFS was also assessed.

Results

The median followup was 21 months, and median age was 54 years. The estimated 5-year locoregional failure-free survival, DFS, and overall survival rates were 87.4%, 70%, and 81%, respectively. DFS was 59.5% in patients with nodal metastases in FDG PET/CT and 100% in node negative patients (p:0,017). DFS was 50% and 79.4% in MRI node-positive and in node-negative patients, respectively (p:0,260). In addition, the nodal SUVmax (p: 0.005) and posttreatment response in FDG PET-CT (p < 0.001) were significant prognostic factors for DFS. Furthermore, primary tumor volume in MRI (p:0,982), node positivity in MRI (p:0,301), and response in posttreatment MRI (p:0,26) are not significant prognostic factors for DFS.

Conclusion

As a result, FDG PET/CT has higher accuracy than MRI in detecting lymph node metastasis, and tumor volume reduction on FDG PET/CT images was greater than that on MRI images after CCRT.  相似文献   
3.
IntroductionOnly 5%–15% of thyroid surgical specimens are reported as malignant. Most of the operations are performed due to suspicion of malignancy as a result of fine needle aspiration biopsy but invasiveness, non-diagnostic results and potential repeat biopsies are disadvantages of fine needle aspiration biopsy.ObjectiveThe aim of this study was to investigate the effectiveness of simultaneously using both the strain ratio and elasticity score in the differential diagnosis of thyroid nodules, as well as to assess the compatibility of these two methods.MethodsA total of 144 nodules were included in the study. The final histopathologic diagnosis was used as the reference standard. The area under the curve sensitivity, specificity, and cut-off values of the strain ratio and elasticity score were determined using receiver operating characteristic curve analysis. The compatibility and comparison of strain ratio and elasticity score were also performed.ResultsTwenty eight nodules (19.4%) were malignant. The strain ratio and elasticity score results were found to be significantly successful in predicting thyroid malignancy (p < 0.001 for both). Moreover, the area under the curve for the strain ratio and elasticity score were found to be 0.944 and 0.960, respectively. The diagnostic accuracy of the elasticity score was found to be superior to that of the strain ratio, but this difference was not statistically significant (p = 0.456). When the compatibility of the strain ratio and elasticity score was examined, the two evaluations were revealed to be statistically consistent with each other (Kappa = 0.767; p < 0.001). When the strain ratio and the elasticity score were used together, the specificity of capturing the correct diagnosis increased from 84.5% to 93.1%.ConclusionWhen the strain ratio an elasticity score were used together for the differential diagnosis of thyroid nodules, more accurate results were obtained. Thus, combining both methods may be a promising alternative to fine needle aspiration biopsy in order to prevent unnecessary surgical interventions for suspected thyroid nodules.  相似文献   
4.
5.
6.
7.
Supraclavicular artery-based flaps provide aesthetic and functional coverage for the head and neck region. Fourteen formalin-fixed cadavers were dissected bilaterally, and 28 supraclavicular arteries were evaluated. The origin of the supraclavicular artery was transverse cervical artery in 62.9% and suprascapular artery in 37.1% of the cases. The origin of the artery was at the level of the medial third of the clavicle in 3.7%; 3.7% of the cases were at the junction of medial and middle third of the clavicle, 33.3% at the level of middle third of the clavicle, 11.1% at the junction of middle and lateral thirds, 44.4% at the level of lateral third, and 3.7% at the level of acromioclavicular joint. The mean values of the results were as follows: The diameter of the artery was 1.0 mm at the origin. The distance of the origin of the artery from sternoclavicular joint and from the upper border of the clavicle was 76.4 and 22.2 mm, respectively. The average length of the artery was 70.8 mm. In all dissections, the artery was deep to the platysma muscle. Forty-one percent of supraclavicular arteries accompanied the middle supraclavicular nerve, whereas 59% of the arteries run with lateral supraclavicular nerve. The supraclavicular artery had a parallel course to the 2 horizontal imaginary lines passing from the coracoid process and acromion in 63% of the cases; 18.5% of the arteries were oblique, and 18.5% were vertical to the imaginary lines. The venae comitantes were double in all dissections.  相似文献   
8.
Gracilis muscle flap is commonly used in reconstructive surgery. The gracilis muscles of 15 formalin-fixed adult cadavers (30 cases) were dissected with 4× loupe magnification. The most proximal pedicle of gracilis muscle was the deep branch of the medial circumflex femoral artery. It was located 60 mm from the pubic tubercle and had a diameter of 0.9 m on the average. The second pedicle was the medial circumflex femoral artery. It was the dominant pedicle in 13% of the cases. The mean diameter of the artery was 1.2 mm, and it entered the muscle 98 mm from the pubic tubercle. The third artery that nourished the muscle was deep femoral artery. It was the dominant pedicle in 87% of the cases. It had a mean diameter of 1.6 mm with a length of 54 mm. The most distant pedicles originated from the superficial femoral artery. They were present in all cases and were double in 77% of the cases. Mean diameter and length of the artery were 1.4 and 52 mm, respectively. They entered the muscle 266 mm from the pubic tubercle. These distal pedicles seem to be large enough to elevate the middle part of the muscle as a free flap.  相似文献   
9.
With a view to understanding the structure-property relation of a silicone-based soft lining denture material after polymerization, its chemical composition and viscoelastic properties were investigated. Chemical compositions of the cured and uncured polymers of a commercial silicone permanent soft liner were determined by infrared spectroscopic analysis, nuclear magnetic resonance (NMR), and X-ray photoelectron spectroscopy. Dynamic mechanical analysis (DMA) method was used to investigate the viscoelastic behavior of the cured polymer of liner. Spectroscopic analysis showed that the main component of soft liner was vinyl-terminated poly(dimethylsiloxane), and the adhesive was 3-methacryloxypropyltrimethoxy silane. NMR results revealed that other components included benzoyl peroxide as initiator for polymerization and also silicilic acid. Surface analysis by XPS provided interesting insights about the nature of adhesive bonding, as well as diffusion of silicilic acid through the matrix of the processed material and leaching-out. DMA results showed a two-phase character, and that the cured polymer was highly elastic.  相似文献   
10.
PURPOSE: To measure the activity of superoxide dismutase (SOD) in the synovial fluid of patients with temporomandibular joint internal derangement and to show the relationship between the activity of SOD and the severity of the disease. MATERIALS AND METHODS: Twenty patients with internal derangement were classified according to Wilkes by clinical radiological examinations. SOD activity was measured by the method based on nitrobluetetrazolium reduction rate. RESULTS: The activity of SOD seemed to be progressively decreased as the stage of the disease increased. CONCLUSION: The reduction of SOD activity observed may result from insufficient scavenging capacity of free radicals. Further investigation and longitudinal studies are required to determine the role of antioxidants that scavenge the free radicals in temporomandibular joint disorders.  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