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   380篇
  免费   32篇
耳鼻咽喉   5篇
儿科学   6篇
妇产科学   1篇
基础医学   68篇
口腔科学   4篇
临床医学   41篇
内科学   55篇
皮肤病学   5篇
神经病学   56篇
特种医学   22篇
外科学   73篇
预防医学   14篇
眼科学   1篇
药学   39篇
肿瘤学   22篇
  2023年   8篇
  2022年   9篇
  2021年   15篇
  2020年   16篇
  2019年   12篇
  2018年   17篇
  2017年   9篇
  2016年   14篇
  2015年   14篇
  2014年   16篇
  2013年   31篇
  2012年   39篇
  2011年   30篇
  2010年   8篇
  2009年   15篇
  2008年   20篇
  2007年   19篇
  2006年   16篇
  2005年   11篇
  2004年   11篇
  2003年   4篇
  2002年   12篇
  2001年   6篇
  2000年   17篇
  1999年   6篇
  1998年   5篇
  1997年   1篇
  1996年   1篇
  1994年   2篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1990年   3篇
  1989年   2篇
  1987年   3篇
  1985年   1篇
  1984年   1篇
  1981年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1974年   1篇
  1971年   2篇
  1970年   1篇
  1967年   2篇
  1964年   2篇
  1963年   1篇
  1942年   1篇
  1929年   1篇
排序方式: 共有412条查询结果,搜索用时 0 毫秒
21.
Organisation of the sympathetic skin response in spinal cord injury   总被引:3,自引:0,他引:3       下载免费PDF全文
OBJECTIVES: The sympathetic skin response (SSR) is a technique to assess the sympathetic cholinergic pathways, and it can be used to study the central sympathetic pathways in spinal cord injury (SCI). This study investigated the capacity of the isolated spinal cord to generate an SSR, and determined the relation between SSR, levels of spinal cord lesion, and supraspinal connections. METHODS: Palmar and plantar SSR to peripheral nerve electrical stimulation (median or supraorbital nerve above the lesion, and peroneal nerve below the lesion) were recorded in 29 patients with SCI at various neurological levels and in 10 healthy control subjects. RESULTS: In complete SCI at any neurological level, SSR was absent below the lesion. Palmar SSR to median nerve stimuli was absent in complete SCI with level of lesion above T6. Plantar SSR was absent in all patients with complete SCI at the cervical and thoracic level. In incomplete SCI, the occurrence of SSR was dependent on the preservation of supraspinal connections. For all stimulated nerves, there was no difference between recording from ipsilateral and contralateral limbs. CONCLUSIONS: No evidence was found to support the hypothesis that the spinal cord isolated from the brain stem could generate an SSR. The results indicate that supraspinal connections are necessary for the SSR, together with integrity of central sympathetic pathways of the upper thoracic segments for palmar SSR, and possibly all thoracic segments for plantar SSR.  相似文献   
22.
International differences in ageing and spinal cord injury   总被引:1,自引:0,他引:1  
DESIGN: The present study is part of a programme of longitudinal research on ageing and spinal cord injury involving three populations - American, British and Canadian. The design was multivariate. OBJECTIVE: To identify international differences in outcomes associated with ageing and spinal cord injury. SETTING: A sample of 352 participants was assembled from five large, well-established databases. The Canadian sample was derived from the member database of the Canadian Paraplegic Association (Ontario and Manitoba divisions). The British sample was recruited from Southport Hospital's Northwest Regional Spinal Injuries Centre and Stoke-Mandeville Hospital's National Spinal Injuries Centre. The American sample has been recruited through Craig Hospital in Denver, Colorado. METHODS: The sample included individuals who had incurred a spinal cord injury at least 20 years previously; were admitted to rehabilitation within 1 year of injury; were between age 15 and 55 at the time of injury. Data were collected using a combination of self-completed questionnaires and interviews. Data included medical information, general health, hospitalisations, and changes in bladder and bowel management, equipment, pain, spasticity, the need for assistance, and other health issues. RESULTS: Clear international differences existed between the three samples in the three different countries. After controlling for sampling differences (ie, differences in age, level of lesion, duration of disability, etc.), the following differences were seen: (1) American participants had a better psychological profile and fewer health and disability-related problems; (2) British participants had less joint pain and less likelihood of perceiving they were ageing more quickly; (3) Canadians had more health and disability-related complications (particularly bowel, pain and fatigue problems). CONCLUSION: These differences are discussed in terms of socio-political, health care system and cultural factors that might be used to explain them, and to generate hypotheses for future research.  相似文献   
23.
Hospital readmissions in people with chronic spinal cord injury   总被引:2,自引:0,他引:2  
STUDY DESIGN: Longitudinal observational. OBJECTIVES: To examine frequency and duration of hospital readmissions in a population based sample of people with chronic spinal cord injury (SCI) and to look at medical reasons necessitating readmissions and factors influencing them. SETTING: National Spinal Injuries Centre, Stoke Mandeville Hospital, Aylesbury, UK and Regional Spinal Injuries Centre, District General Hospital, Southport, UK. METHODS: One-hundred-and-ninety-eight SCI patients, all injured more than 20 years ago, were interviewed on three occasions and their medical records reviewed for the period 1990 - 1996. RESULTS: Between 1990 and 1996, 127 patients (64% of the sample) required hospital treatment for late medical complications, with 481 readmissions between them and the mean length of stay of 12.03 days per readmission. Only 58% of all readmissions were into specialised spinal injuries centres. Averaged over the entire sample, the readmission rate was 0.4 readmissions per person at risk per year, and the occupancy rate was 4.9 bed-days per person at risk per year. The most frequent reason for readmissions were urinary tract complications (40.5% of all readmissions) and the highest bed occupancy was for skin problems (32.2% of all bed-days). When compared with the non-hospitalised group (36% of the sample), the readmitted patients had longer duration of paralysis and lower disability and handicap scores as measured by Functional Independence Measure (FIM) and Craig Handicap Assessment & Reporting Technique (CHART). The subgroups did not differ significantly by neurological grouping or age. CONCLUSIONS: Urinary and skin complications are the two main reasons for hospital readmissions in people with chronic SCI. Risk of readmissions increases with time since injury and with disability and handicap severity. Hospital bed requirements for people with chronic SCI are greater than the amount of clinical provision currently available in specialised spinal centres. In order to meet the needs of the growing SCI population, more specialised spinal injuries care beds will be needed. Spinal Cord (2000) 38, 371 - 377.  相似文献   
24.
Occupational intoxication with carbon monoxide   总被引:1,自引:0,他引:1  
The most important safety measure for prevention of CO poisoning is the installation of automatic systems that signal high CO concentrations in the work environment. Public health measures that include stringent pollution control, introduction of low-cost CO monitors, and public education aimed at the high-risk population (e.g., new workers, drivers) should decrease the number of deaths from CO poisoning and should save productive years of life. Toxicity of CO is a consequence of tissue hypoxia created by the displacement of oxygen from hemoglobin and the subsequent impairment of oxygen release to the tissues. Early symptoms of CO intoxication are insidious and can resemble other diseases; physical examination may be unremarkable. For these reasons, many cases of CO poisoning are not readily recognized.  相似文献   
25.
INTRODUCTION: The possibilities and limitations of fibrin glue (FG) usage in nephron-sparing surgery were studied. MATERIALS AND METHODS: A prospective experimental study was carried out in 50 pigs: 30 with polar resection, and 20 with mediorenal wedge resection of the kidney. Hemostatic sutures, FG, and FG with a muscle 'cup' in animals with polar resection of the kidney were compared. FG and sutures in animals with the wedge resection of the kidney were studied as well. Bleeding, hot ischemia time, complication rate, and additional scarring were also analyzed. RESULTS: Suture hemostasis is safe but with significant adverse effects in both polar and wedge resection of kidney. FG was not efficient as a sole hemostatic agent for polar resection. It was as efficient as hemostatic suture for wedge resection of the kidney. FG with a muscle 'cup' on a pole of the kidney achieved good results in animals with polar resection of the kidney. Histological analysis confirmed better results with FG because of both the less intense and smaller area of additional scarring. CONCLUSION: FG is a reliable and efficient hemostatic agent for nephron-sparing surgery whenever both sided gluing is possible.  相似文献   
26.
Progression of kidney damage was studied in 18 patients with Balkan endemic nephropathy (BEN), with a mean 15-year follow-up after renal biopsy. According to kidney function, estimated by 99mTc-DTPA clearance, patients were divided into three groups: with apparently normal kidney function (clearance 103.5+/-21.3 mL/min/1.73 m2), with incipient renal failure (clearance 65.5 +/- 11.3), and with advanced renal failure (clearance 28.0+/-6.2). The mean yearly decrease of glomerular filtration rate was 2.74 mL/min. In two patients, an increase of kidney function was recorded. Six patients become dialysis dependent, two from the group with incipient renal failure, but all four from the group with advanced renal failure. Three patients died after 8 to 12 years of follow-up, one from causes unrelated to kidney disease and two from end-stage renal failure. This study has shown that BEN is characterized by a slow course and prolonged evolution, modified by medical supervision and treatment.  相似文献   
27.
Savic I  Osterman Y  Helms G 《NeuroImage》2004,21(1):163-172
OBJECTIVE: While it is generally accepted that the thalamo-cortical loop is abnormal in idiopathic generalized epilepsy (IGE), it is uncertain whether this loop is similarly affected among different IGE syndromes. We recently demonstrated reduced frontal lobe levels of N-acetyl aspartate (NAA) in patients with juvenile myoclonic epilepsy (JME). The present follow-up study investigates if similar or other types of changes exist in subjects with pure primarily generalized tonic clonic epilepsy (GTCS). METHOD: Twenty patients with GTCS, 26 patients with JME, and 10 matched healthy controls were investigated with quantitative single voxel MR spectroscopy (MRS) measurements of NAA, choline (Cho), creatine (Cr), and myo-inositol (mI) at 1.5 T scanner. The voxels were placed over the right cerebellum, right thalamus, prefrontal, occipital cortex, and over a spherical phantom above the subject's head. RESULTS: Patients with JME had reduced frontal lobe NAA (mmol/l) in relation to controls (9.8 +/- 1.1 vs. 10.8 +/- 0.7, P = 0.01), as well as GTCS patients (9.8 +/- 1.1 vs. 10.6 +/- 0.7, P = 0.007), whose values were normal. Patients with GTCS, on the other hand, showed significantly lower thalamic NAA than controls (9.7 +/- 1.0 vs. 10.8 +/- 0.9, P = 0.002), and both groups of patients had reduced thalamic Cho, and mI; [CHO: 2.0 +/- 0.4 (control) vs. 1.61 +/- 0.3 (JME) P = 0.001, and vs. 1.57 +/- 0.3 (GTCS) P = 0.0005; MI: 4.8 +/- 1.5 (control) vs. 3.3 +/- 1.4 (JME) P = 0.003, and vs. 3.2 +/- 1.5 (GTCS), P = 0.002]. No other regional changes were observed. CONCLUSION: The present MRS data emphasize the involvement of thalamus in IGE. They also show partly differentiated alterations within the thalamo-cortical loop in JME vs. GTCS. The various clinical expressions of IGE may, thus, be associated with more localized neuroanatomical substrates than generally believed.  相似文献   
28.
29.
STUDY DESIGN: A prospective observational study. OBJECTIVES: To compare the height and arm span measurements in childhood spinal cord injured (SCI) people and examine the subsequent effect on calculating the predicted lung function using standard formulae and to discuss which of the two measurements is the most appropriate to use in these formulae. SETTING: National Spinal Injuries Centre, Stoke Mandeville Hospital, Aylesbury, UK. METHOD: A total of 12 children had lung function tests performed and at the same time had height and armspan measured. The predicted lung function was calculated twice; once using height and then using arm span and compared. The actual lung function test results were expressed as percentage of the two predicted values, respectively, and compared. RESULTS: The difference between the mean height (1499 mm) and arm span (1649 mm) measurements was significant (P<0.001). In all cases, the arm span measurement was greater than the height. The two predicted lung function values (one calculated using height and the other armspan) were significantly different (P<0.001). When lung function test results were expressed as percentage of the two predicted values they gave a very different interpretation of the results. The actual performance was much lower than the predicted values if arm span, rather than height, was used in prediction equations. CONCLUSION: In childhood SCI, the difference in height and arm span is significant. This affects the predicted lung function values significantly and thus changes the interpretation of the lung function test results. The most appropriate measurement to use in prediction equations (height or arm span) in these subjects is yet to be decided.  相似文献   
30.
OBJECTIVE: To investigate whether cerebral levels of N-acetyl aspartate (NAA), and glutamine + glutamate (Glx), are interictally altered in the epileptogenic regions of patients with partial seizures. MATERIAL AND METHODS: NAA, Glx, creatine (Cr), choline (Cho) and myo-inositol (mI) was measured in 28 patients with partial epilepsy and 10 healthy controls using localized 1H magnetic resonance spectroscopy. According to the multimethodological consensus, the epileptogenic region was mesial temporal in 18 and neocortical in 10 patients. RESULTS: The Glx/NAA and Glx/Cr ratios in epileptogenic regions were higher, and the NAA/Cr ratios lower than in the homologous regions (P=0.013, P=0.002 and P<0.0001). Applying the 95% confidence interval of controls, 17 of the 20 mesial temporal epileptogenic regions were correctly identified by an increased Glx/NAA and 15 of 20 by a decreased NAA/Cr ratio. Among patients with neocortical epilepsy the Glx/NAA ratio was increased in 8 of the 10 epileptogenic regions, whereas the NAA/Cr ratio was decreased in three. CONCLUSION: Both Glx and NAA are useful to identify the epileptogenic zone. The Glx/NAA ratios may be particularly useful to indentify neocortical epileptogenic regions.  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