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   378篇
  免费   17篇
耳鼻咽喉   1篇
儿科学   15篇
妇产科学   8篇
基础医学   33篇
口腔科学   7篇
临床医学   18篇
内科学   37篇
皮肤病学   6篇
神经病学   143篇
特种医学   69篇
外科学   26篇
综合类   8篇
预防医学   3篇
眼科学   3篇
药学   9篇
中国医学   2篇
肿瘤学   7篇
  2023年   2篇
  2021年   8篇
  2020年   4篇
  2019年   5篇
  2018年   5篇
  2017年   3篇
  2016年   5篇
  2015年   3篇
  2014年   5篇
  2013年   16篇
  2012年   20篇
  2011年   20篇
  2010年   17篇
  2009年   17篇
  2008年   19篇
  2007年   25篇
  2006年   19篇
  2005年   8篇
  2004年   3篇
  2003年   6篇
  2002年   4篇
  2001年   7篇
  2000年   4篇
  1999年   7篇
  1998年   18篇
  1997年   14篇
  1996年   17篇
  1995年   10篇
  1994年   8篇
  1993年   7篇
  1992年   2篇
  1991年   4篇
  1990年   4篇
  1989年   3篇
  1988年   10篇
  1987年   7篇
  1986年   6篇
  1985年   10篇
  1984年   2篇
  1983年   5篇
  1982年   2篇
  1981年   5篇
  1980年   8篇
  1979年   2篇
  1978年   2篇
  1977年   7篇
  1976年   5篇
  1975年   2篇
  1974年   1篇
  1939年   1篇
排序方式: 共有395条查询结果,搜索用时 17 毫秒
21.
In this double-blind, randomized trial, which lasted for 2 years, the authors investigated the efficacy of calcium dobesilate on diabetic retinopathy. 68 patients (51 on the active substance, 17 on placebo) participated in the study. The statistical analysis of the results indicate that calcium dobesilate acts as a potent angioprotector, capable of preventing both intra and extraretinal hemorrhages. The drug also lowers the incidence of exudate formation and improves visual acuity.  相似文献   
22.
23.
Amphiphysin autoimmunity: paraneoplastic accompaniments   总被引:2,自引:0,他引:2  
Amphiphysin-IgG was identified in 71 patients among 120,000 evaluated serologically for paraneoplastic autoantibodies. Clinical information was available for 63 patients. Cancer was detected in 50 (mostly limited), proven histologically in 46, and was imaged intrathoracically in 4 patients (lung, small-cell [27] and non-small cell [1]), breast [16] and melanoma [2]). Neurological accompaniments included (decreasing frequency): neuropathy, encephalopathy, myelopathy, stiff-man phenomena, and cerebellar syndrome. In a case examined neuropathologically, parenchymal T-lymphocyte infiltration (predominantly CD8(+)) was prominent in lower brainstem, spinal cord, and dorsal root ganglion. Coexisting paraneoplastic autoantibodies, identified in 74% of patients, predicted a common neoplasm and indicated other neuronal autoantigen targets that plausibly explained several neurological manifestations; for example, P/Q-type Ca(2+)-channel antibody with Lambert-Eaton syndrome (n = 5), anti-neuronal nuclear antibody type 1 with sensory neuronopathy (n = 7), K(+)-channel antibody with limbic encephalitis (n = 1) or neuromyotonia (n = 1), and collapsin response-mediator protein-5-IgG with optic neuritis (n = 3). Patients with isolated amphiphysin-IgG (n = 19) were more likely to be women (with breast cancer, p < 0.05) and to have myelopathy or stiff-man phenomena (p < 0.01). Overall, a minority of women (39%) and men (12%) had stiff-man phenomena. Only 10% of women (some with lung carcinoma) and 4% of men fulfilled diagnostic criteria for stiff-man syndrome.  相似文献   
24.
We have defined a new paraneoplastic immunoglobulin G (IgG) autoantibody specific for CRMP-5, a previously unknown 62-kd neuronal cytoplasmic protein of the collapsin response-mediator family. CRMP-5 is in adult central and peripheral neurons, including synapses, and in small-cell lung carcinomas. Since 1993, our Clinical Neuroimmunology Laboratory has detected CRMP-5-IgG in 121 patients among approximately 68,000 whose sera were submitted for standardized immunofluorescence screening because a subacute neurological presentation was suspected to be paraneoplastic. This makes CRMP-5 autoantibody as frequent as PCA-1 (anti-Yo) autoantibody, second only to ANNA-1 (anti-Hu). Clinical information, obtained for 116 patients, revealed multifocal neurological signs. Most remarkable were the high frequencies of chorea (11%) and cranial neuropathy (17%, including 10% loss of olfaction/taste, 7% optic neuropathy). Other common signs were peripheral neuropathy (47%), autonomic neuropathy (31%), cerebellar ataxia (26%), subacute dementia (25%), and neuromuscular junction disorders (12%). Spinal fluid was inflammatory in 86%, and CRMP-5-IgG in 37% equaled or significantly exceeded serum titers. Lung carcinoma (mostly limited small-cell) was found in 77% of patients; thymoma was in 6%. Half of those remaining had miscellaneous neoplasms; all but two were smokers. Serum IgG in all cases bound to recombinant CRMP-5 (predominantly N-terminal epitopes), but not to human CRMP-2 or CRMP-3.  相似文献   
25.
Transient synovitis of the hip in children: role of US   总被引:7,自引:0,他引:7  
Transient synovitis of the hip remains a common diagnostic problem for the clinician. The physical signs are not pathognomonic of the condition, and the classic technical examinations are of little help. Therefore, the authors retrospectively studied the value of hip arthrosonography in 46 children with clinical symptoms suggesting pathologic hip conditions. In 20 of the 21 patients with a final diagnosis of transient synovitis, articular effusion was detected on ultrasound (US). Conventional radiography showed an increased medial joint space in only eight of these patients. Increased echogenicity of the articular fluid was found in both transient synovitis and septic arthritis. The high sensitivity of US in detecting intraarticular fluid was demonstrated by cadaver studies.  相似文献   
26.
BACKGROUND: Tourette syndrome (TS) is a chronic disorder characterized by motor and vocal tics. Previous studies reported a substantial lag period between disease onset and diagnosis ranging from 3 to 11.9 years. AIMS: To determine the lag period and factors associated with diagnosis delay of TS. METHODS: All files of 185 children with TS attending one neuropediatric unit in Jerusalem were reviewed. Lag time between disease onset, according to DSM criteria, and diagnosis was determined and the contributions of the disease course, comorbidities and epidemiological factors were assessed. RESULTS: A relatively short lag to diagnosis following the onset of diagnosable TS was documented (mean 13.2+/-15.9 months, median 6 months). A relatively longer gap was associated with older age at TS onset (r=0.161, p<0.05) and vocal tics as the first manifestation rather than motor or combined motor and vocal tics (mean=20.3+16.3 months vs 11.9+16.5 and 12.6+15.2, respectively, p<0.05). A relatively shorter gap was associated with tic severity (r=0.13, p<0.05) and presence of comorbid obsessive-compulsive disorder (OCD) (9.5+14.7 months vs. 14.1+16 without OCD, p<0.05). CONCLUSIONS: Lag time to diagnosis is relatively short in our population. Factors associated with a shorter lag (early age of TS onset, motor tics as the first manifestation, greater tics severity and the presence of OCD) may be perceived as disruptive, prompting patient and families to seek medical care. Conversely, vocal tics as the first manifestation, associated with a longer lag, may be misdiagnosed as features of common pediatric conditions, thus delaying diagnosis.  相似文献   
27.
We analyzed the Valsalva maneuver (VM) using a photoplethysmographic technique in 24 normal subjects. We studied the effects of test duration (range 5 to 20 seconds) and magnitude of expiratory pressure (EP, range 20 to 50 mmHg) on maximal (% delta) and time integrated (int) changes in heart rate (HR), and mean (MAP) and pulse (PP) pressures during phases II and IV. At all EPs, there was correlation (P less than 0.01) between % delta MAP in both late phase II and phase IV and duration of the VM. The Valsalva ratio (VR) correlated with test duration only at high EPs. All responses, except the fall in MAP in early phase II and bradycardia in phase IV, correlated with EPs. The VR correlate not only with HR responses in phases II and IV but also with MAP and PP overshoot in phase IV. Correlations between maximal AP and HR changes in either phase II and IV were poor. Our study indicates that the photoplethysmographic technique allows a more rational interpretation of the VM in the clinical setting. The VR cannot be adequately interpreted without comcomitant monitoring of arterial pressure during the VM.  相似文献   
28.
We concurrently measured, by radioimmunoassay, levels of substance P (SP), somatostatin (SST), methionine-enkephalin (Met-Enk), cholecystokinin (CCK), peptide hystidyl-isoleucine (PHI), vasoactive intestinal polypeptide (VIP), and neuropeptide Y (NPY) in the ventral and dorsal gray matter at each segment of the cervical, thoracic, lumbar, and sacral spinal cord, obtained within 6 hours of death from 4 subjects (ages 17 to 55) with no neurologic disease. Levels (pmol/g gray matter) of SP, SST, and Met-Enk throughout and PHI, VIP, and NPY in lumbar and sacral cord were significantly higher in dorsal than in ventral gray matter. PHI, VIP, and NPY were significantly higher in lumbar and especially sacral cord than in cervical and thoracic segments. In rats, a postmortem delay of up to 8 hours did not affect SP, Met-Enk, PHI, or NPY and decreased SST, CCK, and VIP levels. Thus, there is a characteristic profile of neuropeptide distribution in gray matter, which emphasizes the neurochemical heterogeneity along the rostrocaudal and dorsoventral extent of normal human spinal cord.  相似文献   
29.
Female blood donors with low hematocrit levels detected by copper sulfate screening were selected randomly to receive either 75 mg of iron per day, as ferrous gluconate, or a calcium phosphate placebo. Their ferritin, serum iron, total iron-binding capacity, zinc protoporphyrin, and hemoglobin values, as well as their suitability to donate blood, were determined initially (Visit 1) and at four follow-up visits (Visits 2-5). By the second visit, the serum ferritin and iron values of donors receiving iron supplementation differed significantly from those of donors receiving placebo. By the fifth visit, a less marked but significant increase in hemoglobin had occurred in the iron group, but not in the placebo group. At no time was there a significant difference between the groups' suitability to donate blood, with each group donating at almost half of their visits. The authors conclude that iron supplementation at this dose level in deferred female blood donors improves their iron status and hemoglobin levels, but does not significantly increase their suitability to donate blood as compared with the suitability of placebo-treated donors.  相似文献   
30.
Total radical trapping antioxidant potential (TRAP) and exercise   总被引:1,自引:0,他引:1  
The relationship between physical activity, physical fitness and total radical trapping antioxidant potential (TRAP) was examined in the Northern Ireland Health and Activity Survey. This was a cross-sectional population study (n = 1600) using a two-stage probability sample of the population. TRAP was calculated using the sum of the individual serum antioxidant concentrations (urate, protein thiols, ascorbate, alpha tocopherol and bilirubin) multiplied by their respective stoichiometric values. Physical fitness was determined by estimation of VO2max by extrapolation from submaximal oxygen uptake, and physical activity was recorded by computer-assisted interview. Mean serum TRAP concentrations were significantly higher in males (653 +/- 8.2 mumol/l, mean +/- SEM) compared to females (564 +/- 8.0 mumol/l) (p < 0.0001). Both male and female smokers had significantly lower TRAP values than non-smokers (males p < 0.0001, females p = 0.02). In females, there was a positive relationship of TRAP with age (p < 0.001) and body mass index (p < 0.001) but a negative relationship with physical fitness (p < 0.05). The known beneficial effects of exercise and activity do not appear to be directly mediated through increased antioxidant status.   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