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   448篇
  免费   14篇
耳鼻咽喉   1篇
儿科学   10篇
妇产科学   1篇
基础医学   39篇
口腔科学   50篇
临床医学   24篇
内科学   60篇
皮肤病学   2篇
神经病学   32篇
特种医学   32篇
外科学   26篇
综合类   5篇
预防医学   18篇
眼科学   122篇
药学   9篇
肿瘤学   31篇
  2023年   3篇
  2022年   2篇
  2021年   5篇
  2020年   4篇
  2018年   5篇
  2016年   4篇
  2015年   6篇
  2014年   5篇
  2013年   9篇
  2012年   13篇
  2011年   11篇
  2010年   10篇
  2009年   8篇
  2008年   8篇
  2007年   16篇
  2006年   27篇
  2005年   28篇
  2004年   25篇
  2003年   21篇
  2002年   33篇
  2001年   29篇
  2000年   18篇
  1999年   25篇
  1998年   4篇
  1997年   4篇
  1996年   2篇
  1995年   2篇
  1992年   5篇
  1991年   13篇
  1990年   6篇
  1989年   5篇
  1988年   8篇
  1987年   6篇
  1986年   11篇
  1985年   8篇
  1984年   6篇
  1983年   8篇
  1982年   3篇
  1979年   2篇
  1978年   8篇
  1977年   7篇
  1976年   4篇
  1974年   8篇
  1973年   6篇
  1972年   2篇
  1969年   2篇
  1958年   2篇
  1947年   1篇
  1944年   2篇
  1900年   1篇
排序方式: 共有462条查询结果,搜索用时 15 毫秒
1.
2.
CHIP (325 mg/M2), a second generation cisplatin derivative, was administered intravenously every 3 weeks to 85 pediatric patients with recurrent sarcomas (19), osteosarcomas (20), neuroblastoma (23), germ cell tumors (10), and other malignant tumors (7). Thirty-eight of them had been previously exposed to cisplatin. Partial remissions were only observed in 3 of 23 (13% SE=7%) patients having neuroblastoma. Severe thrombocytopenia (65%) and neutropenia (35%) were the dose limiting factors.  相似文献   
3.
4.
Two patients with bilateral extensive confluent choroidal lesions, exudative retinal detachments, positive lyme serology and a typical history are documented: A 32-year-old woman presented 14 days after a "flu-like" illness with bilateral acute extensive choroidal lesions and exudative retinal detachments (OD from 5 to 8:30 o'clock, OS from 5 to 8 o'clock, both including the macula) accompanied by a mild lymphocytic meningitis. The laboratory work-up revealed increased serum and CSF titers of antibodies against Borrelia burgdorferi (Lyme immunofluorescent test (IFT) and Lyme-IgM IFT) which declined after a 14-day treatment with doxycycline (200 mg/d), CSF titers non-detectable (serum IgG: from 1:640 to 1:320, serum IgM: from 1:40 to 1:20). A distinct improvement with visual acuity increasing from OD 0.2/OS 0.3 p to OD/OS 0.8 p was observed after seven days of treatment. A 40-year-old man with a 14-day history of tick-bite developed the same, though more severe ocular findings and a lymphocytic meningitis. The serological work-up revealed increased antibody titers against Borrelia burgdorferi (ELISA); the IgM titer was normal. After a 10-day treatment with penicillin, antibody titers against the spirochete decreased slightly and the patient's neurologic and ophthalmologic status improved dramatically. Five weeks after admission visual acuity was OD/OS 0.5 (compared to OD/OS 0.1) and has remained at 0.8 p (OD/OS) since the ninth week after onset. The clinical course of the disease and the decreasing lyme serology strongly suggest an infection with Borrelia burgdorferi. The authors propose thorough laboratory work-ups including tests for Lyme disease in selected patients with diffuse choroidal lesions.  相似文献   
5.
OBJECTIVES: To determine the prevalence of portrayal of the foramen transversarium of the second cervical vertebra on rotational panoramic radiographs. METHODS: A stratified random sample of 1600 diagnostic-quality rotational panoramic radiographs were retrospectively reviewed. Approximately 100 radiographs each for males and females were reviewed for each of the decades of life up to age 69 and for subjects 70 or older. RESULTS: The foramen was portrayed 29.3% of all radiographs, 35% of females and 22.6% of males. However, when considering only those radiographs in which cervical vertebrae were visible, the foramen was more frequently portrayed in males than in females. Portrayal of the foramen did not differ substantially among age groups. CONCLUSIONS: The foramen transversarium is found sufficiently often on rotational panoramic radiographs that this structure should be identifiable by clinicians who use these images.  相似文献   
6.
BACKGROUND: The mucopolysaccharidoses (MPS) are an inhomogeneous group of disorders of errors in the carbohydrate metabolism with severe ocular involvement (corneal opacification, retinal degeneration, optic atrophy). PATIENT PRESENTATION: We report on a boy aged 12 years, with Morquio A (MPS IV A) syndrome. Ocular findings: progressive pseudoexophthalmus due to shallow orbits, increasing corneal stromal clouding, intermittent dissociated manifest nystagmus of the left eye, nyctalopia. Visual acuity OD cc = 0.16, OS cc = 0.05. Electrophysiology: changes suggesting a symptomatic tapetoretinal degeneration and optic atrophy. TREATMENT AND COURSE OF DISEASE: OS: perforating keratoplasty. Postoperative improvement of visual acuity to 0.25 for nearly a year, followed by progressive reopacification of the corneal graft. Both eyes: progressive signs of tapetoretinal degeneration and optic atrophy. Visual acuity now reduced to OD 0.05, OS 0.1. CONCLUSIONS: Success of a keratoplasty is limited by (1) reopacification of the cornea, (2) visual impairment due to (a) retinal degeneration and (b) optic atrophy. The indication for perforating keratoplasty has to be thought about very carefully in these multimorbid patients. In our patient, beside progressive visual impairment there is a progressive deafness which dominates his social and school life. Attending school is severely complicated by the double handicap. Perforating keratoplasty enabled the boy to attend a school for physically handicapped without a special low-vision care for another year. Progressive visual loss without further treatment options now renders optical and electronic low-vision aids necessary. Although the time of improved visual acuity lasted less than a year, we think patients with a life expectancy of less than 20 years should have every possible improvement of their situation - even if it does not last permanently. We therefore propose perforating keratoplasty in spite of insufficient long-term results.  相似文献   
7.
BACKGROUND: For years the Heidelberg Retina Tomograph has been an established method to diagnose early glaucomatous damages at the optic nerve head. The major difficulty consists in defining the outlayer of the optic nerve head in a 2-dimensional reflective or topographic picture. A 3-dimensional presentation of the ocular fundus could ease the defining very much. The Dresden 3D-display tested provides a true 3-dimensional presentation of the HRT-values measured. METHODS: For the study 5 groups of prediagnosed follow-up examinations were formed, which in their course showed various progression. The examination firstly was carried out by manual defining of the papilla contour on the Dresden 3D-display and secondly by the new automatic contour-finding of the 3D-software. RESULTS: Through the 3-dimensional presentation a more correct position of the contour can be found when drawn manually. As a result some diagnoses of the 2-dimensional HRT-pictures had to be revised. The results proved considerable differences between the automatic outlayer-finding and the probably real position of the papilla borders. CONCLUSION: The 3-dimensional presentation of the HRT-pictures represents an subjective improvement regarding the accuracy of manual contour definition. In particular, the fact that it is feasible to make the pictures rotate around the axes offers completely new insights to the morphology of the disc.  相似文献   
8.
Ischemic ophthalmopathy is the leading ocular symptom of occlusive processes of the internal carotid artery. It can be preceded by embolic symptoms as amaurosis fugax or occlusion of a branch or the main stem of the central retinal artery. Both, ophthalmologists and neurologists, should be familiar with these disturbances as they can involve important diagnostic and therapeutic consequences. Five out of six patients with an angiographically demonstrated extracranial occlusion of one internal carotid artery and a retrograde collateral circulation to the intracranial space via the external carotid and the ophthalmic arteries showed an ischemic ophthalmopathy of the ipsilateral eye. This high coincidence supports the notion that an ischemic ophthalmopathy may not be the result of the occlusive process of the internal carotid artery per se, but may be caused by ocular "steal mechanisms" due to the retrograde orbital collateral circulation.  相似文献   
9.
This study explored the relationship between adenine nucleotide levels in canine renal cortex and renal function following: (a) graded periods of warm ischemia; (b) 48 hours' flush cooling with electrolyte solutions and ice storage; and (c) continuous hypothermic perfusion. Exposure to normothermic ischemia resulted in a rapid (within 15 minutes) degradation of ATP to ADP and AMP as well as a slow decline in total adenine nucleotide (TAN) to levels which were proportional to the duration of the ischemic injury. No functional impairment was evident after 15 minutes' ischemia, but with longer times, both the extent of decline in TAN and the degree of recovery following restoration of blood flow could be used to predict the quality of renal function.The relationship between TAN levels and function was of less predictive value following cold storage or continuous perfusion. The efficacy of intracellular flush solutions could not be attributed solely to conservation of TAN, nor did the well-maintained TAN levels during continuous perfusion necessarily lead to significantly better 48-hour storage than flush cooling with C2 solution.
Résumé Cette étude faite chez le chien examine la corrélation entre la fonction rénale et le taux d'adénine nucléotide dans le cortex rénal suite à: 1) différentes périodes d'ischémic chaude; 2) entreposage sur glace pendant 48 heures apres flushing avec des solutions électrolytiques; 3) hypotermie par perfusion continuelle. L'ischémie chaude a produit une dégradation rapide de l'ATD en ADP et AMP (en moins de 15 minutes) et une diminution progressive de la quantité totale d'adénine nucléotide (TAN) proportioneile à la durée de la période ischémique. La fonction rénale n'a pas été affectée par des périodes d'ischémie de 15 minutes ou moins. Suite à des périodes ischémiques plus longues cependant, la chutte des taux de TAN et leur niveau de rétablissement après réouverture de la circulation sanguine ont permis de prédire la qualité de la fonction rénale. Après storage au froid ou perfusion continue, la relation entre les taux de TAN et la fonction rénale est disparue. Le flushing à l'aide des solutions de type intracellulaire, malgré sa faible capacité à conserver les taux de TAN s'est avéré une méthode d'entreposage aussi efficace que la perfusion continuelle, laquelle a maintenu des taux normaux de TAN.


Supported by Veterans Administration Research Grant 1519-01.  相似文献   
10.
PURPOSE: To assess, if a slow multifocal stimulus (mfS) can provoke a perfusion response that can be measured with the Retinal Vessel Analyzer (RVA). METHODS: Seventeen eyes were examined. Pupils were dilated. A 120-second baseline recording was obtained with the RVA. The subject then turned to view an mfS for 56 s. The mfS consisted of 103 hexagons flickering according to an m-sequence with a stimulus base interval of 53.3 ms (L(max) = 100 cd/m(2), L(min) < 1 cd/m(2)). Immediately thereafter, the subject turned to the RVA, where measurements were resumed as soon as the same retinal vessel was targeted and continued for 104 s. Stimulation and recording was repeated twice. The diameter of a retinal vein and artery was measured for a length of at least 1 mm. The maximum vessel response was obtained by linear interpolation of the measured response within the 20 s following mfS. RESULTS: On average, veins dilated by 6.8% and arteries by 7% following mfS (p > 0.005). Such a dilatation could be observed in 9 veins and 7 arteries. Three venous and 2 arterial measurements did not show a dilatation following mfS. However, 13 of 34 measurements could not be analyzed due to signal problems or because the time from the end of mfS and the uptake of measurement exceeded 20 s. CONCLUSION: This slow multifocal ERG stimulus results in a dilatation of arteries and veins that can be measured with the RVA. Coupling an mfS to the RVA has the potential to topographically map changes in retinal perfusion in relation to the respective retinal area stimulated. When implementing the mfS into the RVA setup in order not to lose time due to the refixation in the RVA following mfS, one is required to take the transient nature of this perfusion change into consideration.  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