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   425篇
  免费   19篇
耳鼻咽喉   2篇
儿科学   4篇
妇产科学   6篇
基础医学   78篇
口腔科学   16篇
临床医学   47篇
内科学   68篇
皮肤病学   21篇
神经病学   30篇
特种医学   43篇
外科学   53篇
综合类   3篇
预防医学   20篇
眼科学   11篇
药学   17篇
中国医学   2篇
肿瘤学   23篇
  2023年   2篇
  2022年   7篇
  2021年   7篇
  2020年   7篇
  2019年   4篇
  2018年   9篇
  2017年   6篇
  2016年   6篇
  2015年   14篇
  2014年   17篇
  2013年   17篇
  2012年   37篇
  2011年   24篇
  2010年   13篇
  2009年   10篇
  2008年   28篇
  2007年   21篇
  2006年   21篇
  2005年   24篇
  2004年   24篇
  2003年   35篇
  2002年   24篇
  2001年   19篇
  2000年   5篇
  1999年   4篇
  1998年   12篇
  1997年   7篇
  1996年   3篇
  1995年   6篇
  1994年   2篇
  1993年   2篇
  1992年   3篇
  1989年   2篇
  1987年   1篇
  1986年   1篇
  1985年   3篇
  1982年   2篇
  1980年   2篇
  1977年   1篇
  1976年   1篇
  1971年   1篇
  1965年   1篇
  1963年   3篇
  1962年   2篇
  1961年   1篇
  1958年   1篇
  1957年   1篇
  1923年   1篇
排序方式: 共有444条查询结果,搜索用时 31 毫秒
1.
Purpose We report a case of periocular subcutaneous macrofilariasis as an initial sign of a systemic Loa loa infection.Methods Thorough history, eye examination and surgical intervention. Parasitological and serological analysis.Results A periocular adult Loa loa worm was extracted from the left upper eyelid in an African student living in Germany after presenting to our department with intermittent attacks of painful lid swelling. Four weeks later he presented with Calabar swellings in his arms without serological evidence of microfilaria and was treated with diethylcarbamazine.Conclusion Due to increasing migration of populations to Europe rare manifestations of ocular loiasis are becoming more common. Intermittent painful eyelid swelling in patients who visited or have lived in Africa should always raise the suspicion of systemic loiasis.  相似文献   
2.
The combination of small-animal PET and MRI data provides quantitative in vivo insights into cardiac pathophysiology, integrating information on biology and morphology. We sought to determine the feasibility of PET and MRI for the quantification of ischemic injury in the rat model. METHODS: Fourteen healthy male Wistar rats were studied with 18F-FDG PET and cine MRI. Myocardial viability was determined in a transmural myocardial infarction model in 12 additional rats, using 18F-FDG PET and delayed-enhancement MRI with gadolinium-diethylenetriaminepentaacetic acid. All PET was acquired with a dedicated small-animal PET system. MRI was performed on a 1.5-T clinical tomograph with a dedicated small-animal electrocardiographic triggering device and a small surface coil. RESULTS: In normal rats, 18F-FDG uptake was homogeneous throughout the left ventricle. The lowest mean uptake of the 18F-FDG was found in the apical regions (79% +/- 6.0% of maximum) and the highest uptake was in the anterior wall (93% +/- 4.3 % of maximum). Myocardial infarct size as determined by histology correlated well with defects of glucose metabolism obtained with 18F-FDG PET (r = 0.89) and also with delayed-enhancement MRI (r = 0.91). Left ventricular ejection fraction in normal rats measured by cine MRI was 57% +/- 5.4% and decreased to 38% +/- 12.9% (P < 0.001) in the myocardial infarction model. CONCLUSION: Integrating information from small-animal PET and clinical MRI instrumentation allows for the quantitative assessment of cardiac function and infarct size in the rat model. The MRI measurements of scar can be complemented by metabolic imaging, addressing the extent and severity of ischemic injury and providing endpoints for therapeutic interventions.  相似文献   
3.
Eye movements were studied in 13 patients with Friedreich's ataxia and correlated with MRI findings to investigate whether oculomotor abnormalities can be traced to cerebellar disturbances in this disease. One of the most prominent eye signs was fixation instability (square-wave jerks, SWJ.). Besides SWJ the patients showed various combinations of cerebellar, vestibular and brain-stem oculomotor signs. Our patients did not comprise a homogeneous group with regard to their oculomotor findings. There was no correlation between the severity of any of the so-called cerebellar oculomotor disturbances and the number of SWJ. We tried to correlate the extent of oculomotor disturbances with floccular atrophy and atrophy of the dorsal vermis on MRI in seven of the patients. None of the oculomotor features (including SWJ) correlated with flocculus or dorsal vermis size. Furthermore, floccular and vermal measurements on MRI were normal. Accordingly, we think it unlikely that the oculomotor disturbances, including SWJ, are attributable to cerebellar pathology per se.  相似文献   
4.
5.
Zusammenfassung Mit Krebs-Ringerlösung durchströmte Rattenherzen geben um so weniger Kreatin an die Durchströmungsflüssigkeit ab, je schonender sie präpariert wurden.Nach Zugabe von 3 mg bzw. 5 mg Kreatin zu 100 ml Durchstrom nahmen die meisten Herzen innerhalb von 30 min 400 bzw. 830 Kreatin/g Trockengewicht auf. Weitere Steigerung des Kreatinangebotes verbesserte die Kreatinaufnahme nicht, ebensowenig wie Zugabe von Glucose. Enthielt der Durchstrom Insulin, so wurde die Kreatinaufnahme signifikant erhöht.Die Mehrzahl der mit Kreatin durchströmten Herzen nahm aus der Krebs-Ringerlösung Phosphat auf.Kalium wurde von einigen Herzen abgegeben, von anderen aufgenommen. Die Kaliumaufnahme aus dem Durchstrom war bei geschädigten Herzen am größten. Zusammenhänge zwischen dem Verhalten von Kalium einerseits und Kreatin oder Phosphat andererseits wurden in den Versuchen an isolierten Herzen nicht erkennbar.
Summary Rat hearts perfused with Krebs' Ringer solution, yielded creatine in the perfusion fluid; the more carefully the hearts were dissected, the smaller was the yield.When creatine was added to the perfusion fluid in concentrations of 3 or 5 mg-%, the hearts took up creatine in most cases to the extent of 400g or 830µg respectively, per g dry weight. A further increase in the creatine concentration did not improve the creatine uptake, nor did an addition of glucose to the perfusion fluid. When the latter contained insulin, the creatine uptake was significantly increased.The majority of the creatine-perfused hearts took up phosphate from the Krebs' Ringer solution.During perfusion some of the hearts yielded potassium, others took up potassium. The potassium uptake was greatest with hearts which had been damaged during the dissection. No connection could be observed in the experiments with isolated hearts between the behaviour of potassium on the one hand, and that of creatine or phosphate on the other.


Ausgeführt mit Unterstützung des Landes Nordrhein-Westfalen (Landesamt für Forschung).

Herrn Prof. Dr.E. Lehnartz zum 65. Geburtstag.  相似文献   
6.
Lymphocyte clonal restriction is caused by priming the immune system with an antigen and has been referred to infectious disease study as "original antigenic sin" (OAS), described first for influenza by Francis. OAS is a dominant feature of a normal immune response. Benefits of OAS come from the initial contact with the pathogen, which induces immunological memory. Memory is achieved by priming B and T cells of an immunologically na?ve host, and confers protection against infection with the antigen-related pathogen. Thus, a restricted antibody response to viral or parasite antigens is not per se pathogenic. However, the interplay between a "locked-in" immune response and the high genetic variation of the pathogenic agent can result in a deception of the immune system. In the following, clonal restriction of the immune response to HIV is described by giving examples of restricted anti-HIV antibody formation in maternally infected children. Clonal restriction results in host resistance of infected individuals to emerging HIV variants and quasispecies. The problems of classical approaches of vaccine design in AIDS and the lack of protection in vaccinated patients is reviewed.  相似文献   
7.
IntroductionFibroepithelial polyps (FEP) of the lower urinary tract are relatively common in adults but rare in children, with fewer than 250 cases reported in the literature to date.ObjectiveThe aim of this study was to address the experience of FEP management in children.Study designA retrospective multicenter review was undertaken in children with defined FEP of the lower urinary tract managed between 2008 and 2018. The data at 18 pediatric surgery centers were collected. Their demographic, radiological, surgical, and pathological information were reviewed.ResultsA total of 33 children (26 boys; 7 girls) were treated for FEP of the lower urinary tract at 13 centers. The most common presentation was urinary outflow as hematuria (41%), acute urinary retention (25%), dysuria (19%), or urinary infections (28%). A prenatal diagnosis was made for three patients with hydronephrosis. Almost all of the children (94%) underwent ultrasound imaging of the urinary tract as the first diagnostic examination, 23 (70%) of them also either had an MRI (15%), cystourethrography (25%), computerized tomography (6%), or cystoscopy (45%). Two of these children (6%) had a biopsy prior to the surgery. The median preoperative delay was 7.52 (range: 1–48) months. Most of the patients were treated endoscopically, although four (12.1%) had open surgery and two (6.1%) had an additional incision for specimen extraction. The median hospital stay was 1.5 (range: 1–10) days. There were no recurrences and no complications after a median follow-up of 13 (range: 1–34) months.DiscussionThe main limitation of our study is the retrospective design, although it is the largest one for this pathology.ConclusionThis series supports sonography as the most suitable diagnosis tool before endoscopy to confirm the diagnosis and to perform the resection for most FEP in children. This report confirms the recognized benign nature in the absence of recurrences.Level of EvidenceLevel V.  相似文献   
8.
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