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   276篇
  免费   0篇
  国内免费   1篇
耳鼻咽喉   4篇
儿科学   3篇
妇产科学   2篇
基础医学   79篇
临床医学   16篇
内科学   98篇
皮肤病学   2篇
神经病学   2篇
特种医学   5篇
外科学   45篇
预防医学   4篇
眼科学   2篇
药学   6篇
肿瘤学   9篇
  2014年   2篇
  2013年   3篇
  2012年   4篇
  2011年   10篇
  2010年   7篇
  2009年   4篇
  2008年   22篇
  2007年   23篇
  2006年   21篇
  2005年   15篇
  2004年   14篇
  2003年   16篇
  2002年   19篇
  2001年   13篇
  2000年   8篇
  1999年   10篇
  1998年   4篇
  1997年   2篇
  1996年   4篇
  1995年   1篇
  1994年   3篇
  1992年   7篇
  1991年   7篇
  1990年   6篇
  1989年   5篇
  1988年   1篇
  1987年   1篇
  1986年   7篇
  1985年   10篇
  1984年   4篇
  1983年   2篇
  1982年   8篇
  1981年   3篇
  1980年   1篇
  1979年   1篇
  1977年   2篇
  1976年   2篇
  1975年   3篇
  1974年   2篇
排序方式: 共有277条查询结果,搜索用时 0 毫秒
21.
Renal cancer represents accounts for approximately 3% of all adult malignancies with a rising incidence. Incidental diagnosis is mostly based upon ultrasound (US). US and Computed tomography (CT) are the standard imaging modalities for detecting renal cell cancer (RCC). Differentiation between malignant and benign renal tumors is of utmost importance. Contrast enhanced ultrasound (CUS) seems to be a promising new diagnostic option for diagnosis and preoperative treatment planning for patients with renal cancer. It is an additional examination to baseline ultrasound and CT. We report a case of a 37-year-old woman with a papillary renal cell cancer in which CUS helped to differentiate dignity of the tumor. CUS is an additional examination to baseline ultrasound and CT. It is a less invasive technique than contrast enhanced CT and shows even slight tumor blood flow. In addition it may allow a more rapid diagnosis, because of its bedside availability.  相似文献   
22.
OBJECTIVE: To investigate the extent to which B-flow and B-flow with 3D postprocessing and speckle reduction imaging (SRI) have advantages in appraising the morphology of a high-grade stenosis of the internal carotid artery (ICA) for preinterventional planning and for postinterventional ultrasonographic follow-up. MATERIALS/METHODS: A comparative appraisal of flow with CCDS, power Doppler, B-flow and 3D B-Flow with SRI were carried out prospectively in 50 patients with >70% stenosis according to NASCET criteria in contrast medium-enhanced MRA before and after the intervention. After stenting of the internal carotid artery (ICA), i.a. digital substraction angiography (DSA) served as an additional reference method. RESULTS: In >70% ICA stenosis, simultaneous imaging of the pre-stenotic, intra-stenotic and post-stenotic flow was attained with B-flow in 45/90 cases (90%), with power Doppler in 39/50 cases (78%) and with CCDS in only 31/50 cases (62%). After intervention, a complete detection of flow without overwriting or blooming artifacts was achieved in all 50 patients only by B-flow. The intrastenotic flow (p<0.05) could be better demarcated against the lumen and the vessel wall before the intervention, whereas the flow within the stent could be very much better appraised after the intervention (p<0.01) using 3D postprocessing of B-flow with additional SRI. Re-stenoses with hypoechoic vascular wall changes (3/50 patients) were detected at an early stage using B-flow. CONCLUSIONS: B-flow technique with SRI and 3D postprocessing can facilitate the intrastenotic detection of flow in >70% ICA stenosis with fewer flow artifacts. After stenting, the perfused vascular lumen shows less flow artifacts compared with CCDS and power Doppler. In order to elucidate hemodynamic changes, additional Doppler examinations are still necessary.  相似文献   
23.
OBJECTIVE: The objective of this study was to evaluate the efficiency of B-Flow ultrasound in diagnosing supraaortic vessel dissections compared with other ultrasound techniques including B scan, Color-Coded Doppler (CCDS) and Power Doppler (PD). MATERIALS AND METHODS: Eighty-eight patients with suspected arterial dissection of the neck vessels were included in this prospective trial. All patients were examined using B scan, Color-Coded Doppler sonography and Power Doppler. After documentation of the diagnoses, the patients were additionally examined by B-Flow ultrasound. Contrast-enhanced magnetic resonance angiography (MRA) was used as reference standard in all cases. RESULTS: Dissections of the carotid artery (n=19) and of the vertebral artery (n=35) were found in 44 patients. B-Flow imaging identified 52 of 54 arterial dissections that were confirmed by MRA. There were no false-positive diagnoses in ultrasound examination. The sensitivity of ultrasound examination using B scan, CCDS and PD in detecting all dissections was 95.9% and 99.1% with additional B-Flow examination. Sensitivity using B-Flow increased from 98.3% to 100% for carotid dissections and from 93.3% to 94.3% for vertebral artery dissections. Due to the lack of overwriting artifacts, B-Flow imaging detected residual flow within the false lumen more precisely. The reduced effect of the ultrasound probe angle facilitated imaging of fissures, membranes and low flow phenomena and improved the identification of low-reflection wall structures. The cine mode of the B-Flow showed undulating membrane movement most clearly. Contrast-enhanced MRA in conjunction with axial T1 and T2 weighted sequences enabled the best visualization of intramural hematomas. CONCLUSION: B-Flow imaging can significantly increase the sensitivity of ultrasound examination for dissections of the neck vessels. It also improves the visualization of flow within the true and false lumen, of hypoechoic thrombi and of intramural hematoma.  相似文献   
24.
25.
26.
27.
28.
Piercing and tattooing are the most commonly encountered body modifications. Besides risks of infection and scarring, allergic reactions can also occur. The present multicentric study was the first carried out to evaluate the frequency of allergy consultation for such problems. Of the 138 allergists who responded to two questionnaires, 7.9% had observed allergies to piercing and 18.9% had identified an allergy to long-term henna tattoos. Contact eczema, rhinitis and urticaria were associated with an allergy to nickel. Contact eczema, generalized eczema, pruritis and edema caused by tattoos had been observed. Sensitivity to paraphenyline diamine (PPD) was established in 20/28 cases. After reviewing the literature, we emphasize the risk of serious allergy to PPD, of the need for long term surveillance because of the risk of cutaneous lymphocytoma, and of the difficulty of treating certain cases, all of which require close follow-up.  相似文献   
29.
PURPOSE: Adverse reactions to iodinated contrast media (ICM) share various mechanisms. Anaphylactoid reactions are among the most serious reactions when they are characterized by the elevation of seric tryptase. Pretreatment with corticosteroids and anti-H1 or the use of non-ionic contrast media do not prevent anaphylaxis. Late skin reactions could be mostly related to delayed hypersensitivity. Previous reactions to contrast media, cardiovascular disorders, beta-blockers, asthma, and atopy are risk factors. Female gender and age increase the severity. CURRENT KNOWLEDGE AND KEY POINTS: Anaphylaxis can be demonstrated by intradermal tests and the identification of specific IgEs. Delayed hypersensitivity is shown by the results of epicutaneous tests and the immunohistology of the skin. FUTURE PROSPECTS AND PROJECTS: Allergologic tests are advised in the case of previous reactions. In case of emergency, gadopentetate dimeglumine can be alternatively used. The other risk factors lead to the combination of pretreatment and use of non-ionic monomeric contrast media. Immediate hypersensitivity to iodinated media might increase in the near future with the use of divalent molecules.  相似文献   
30.
The diagnosis of latex allergy is mainly based on prick-tests. In order to improve the efficiency of the diagnosis, a comparative study of three latex materials is carried out in 64 controls and 29 patients allergic to latex = Stallergènes and Allerbio extracts, prepared from crude natural latex, and an ammoniated emulsion of rubber latex (AEL). No adverse reactions are recorded. The specificity is 100% for both extracts, 85% for AEL. Sensitivity is respectively 68%, 63%, 72%. The range of values of the wheal is significantly narrower for Stallergènes extract. 46% of allergic patients are reactive to the three materials. The combined use of three materials reaches an 80% efficiency similar to that of Rast Cap System and the addition of three prick-tests and Rast obtains an efficiency of 93.1%. Using several latex materials could increase the efficiency of the diagnosis, inasmuch as the extracts are generated from natural latex, whereas patients are sensitized to manufactured products originating from ammoniated latex.  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