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   536篇
  免费   74篇
  国内免费   12篇
耳鼻咽喉   8篇
儿科学   6篇
妇产科学   11篇
基础医学   79篇
口腔科学   2篇
临床医学   36篇
内科学   170篇
皮肤病学   31篇
神经病学   131篇
特种医学   14篇
外科学   29篇
综合类   3篇
预防医学   27篇
眼科学   2篇
药学   27篇
肿瘤学   46篇
  2023年   5篇
  2022年   7篇
  2021年   21篇
  2020年   9篇
  2019年   17篇
  2018年   28篇
  2017年   28篇
  2016年   16篇
  2015年   22篇
  2014年   31篇
  2013年   34篇
  2012年   36篇
  2011年   27篇
  2010年   24篇
  2009年   19篇
  2008年   26篇
  2007年   26篇
  2006年   24篇
  2005年   30篇
  2004年   21篇
  2003年   32篇
  2002年   22篇
  2001年   13篇
  2000年   12篇
  1999年   11篇
  1998年   9篇
  1997年   5篇
  1996年   5篇
  1995年   1篇
  1994年   5篇
  1993年   3篇
  1992年   6篇
  1991年   9篇
  1990年   7篇
  1989年   6篇
  1988年   4篇
  1987年   6篇
  1986年   2篇
  1985年   1篇
  1984年   2篇
  1983年   2篇
  1979年   4篇
  1978年   1篇
  1977年   1篇
  1974年   2篇
排序方式: 共有622条查询结果,搜索用时 15 毫秒
41.
OBJECTIVES: Spastic patients were studied to understand whether stance unsteadiness is associated with changes in the control of voluntary force, muscle tone, or reflex excitability, rather than to abnormal posture connected to the motor deficit itself. METHODS: Twenty four normal subjects, 12 patients affected by amyotrophic lateral sclerosis (ALS), seven by spastic paraparesis, and 14 by hemiparesis were studied. All patients featured various degrees of spasticity and paresis but were free from clinically evident sensory deficits. Body sway during quiet upright stance was assessed through a stabilometric platform under both eyes open (EO) and eyes closed (EC) conditions. The sudden rotation of a supporting platform, in a toe up and toe down direction respectively, evoked short (SLR) and medium latency (MLR) reflex responses to stretch of the soleus or the tibialis anterior (TA) muscle. RESULTS: No relation was found between clinical findings (tone, muscle strength, tendon reflexes, plantar response, and duration of disease) and body sway. On average, all patient groups exhibited a forward shift of the centre of foot pressure (CFP) with respect to normal subjects; in addition, paraparetic and to a much larger extent hemiparetic patients showed a lateral shift of CFP. Body sway area was significantly increased only in the hemiparetic patients. No relation was found between position of the CFP and sway within any patient group. Soleus SLR was increased in all patients with respect to normal subjects. TA SLR was often seen in both patients with ALS and paraparetic patients, but only rarely in normal subjects and hemiparetic patients. However, no relation was found between amplitude of soleus or TA SLRs and stabilometric variables. The frequency and size of soleus MLR and TA MLR were decreased in all patients. These responses were decreased in size and not modulated by background EMG in the affected leg of hemiparetic patients, suggesting a disturbed control of spinal reflexes fed by spindle group II afferent fibres. CONCLUSIONS: It is proposed that body posture, paresis, or monosynaptic reflex hyperexcitability do not affect the control of equilibrium during quiet upright stance. In hemiparetic patients, the decreased amplitude of MLRs might be the main cause of the large postural instability. The results are congruent with the hypothesis of a role for group II afferent input in the reflex control of equilibrium.  相似文献   
42.
43.
44.
Lymphedema represents one of the major problem of morbidity in breast cancer therapy. Approximately 15-30% of patients show more or less severe lymphedema of the arm, following cancer therapy. Main pathogenetic mechanisms, risk factors, main grading criteria and scales as LENT-SOMA, CTCv2, CTCAE v3 are presented. A close correlation has been documented between the extent of axillary dissection and the association with radiotherapy in determining an increased risk of lymphedema. Details of surgery and radiotherapy are relevant in the definition of the risk of edema of the arm. Because the axillary area does not correspond to an organ, evaluable parameters as V20 and Dmean available for other organs are not applicable. There is some evidence of a correlation between the irradiation volume and the development of lymphedema. Data of the impact of the dose and its fractionation on the development of lymphedema are contrasting. The monitoring system of late toxicity used by the authors is presented.  相似文献   
45.
High titres of pertussis toxin (PT) antibody have been shown to be predictive of recent infection with Bordetella pertussis. The seroprevalence of standardized anti-PT antibody was determined in six Western European countries between 1994 and 1998 and related to historical surveillance and vaccine programme data. Standardized anti-PT titres were calculated for a series of whole-cell and acellular pertussis vaccine trials. For the serological surveys, high-titre sera (> 125 units/ml) were distributed throughout all age groups in both high- (> 90%) and low-coverage (< 90%) countries. High-titre sera were more likely in infants in countries using high-titre-producing vaccines in their primary programme (Italy, 11.5%; Western Germany, 13.3%; France, 4.3%; Eastern Germany, 4.0%) compared to other countries (The Netherlands, 0.5%; Finland, 0%). Recent infection was significantly more likely in adolescents (10-19 years old) and adults in high-coverage countries (Finland, The Netherlands, France, East Germany), whereas infection was more likely in children (3-9 years old) than adolescents in low-coverage (< 90%; Italy, West Germany, United Kingdom) countries. The impact and role of programmatic changes introduced after these surveys aimed at protecting infants from severe disease by accelerating the primary schedule or vaccinating older children and adolescents with booster doses can be evaluated with this approach.  相似文献   
46.
OBJECTIVE: To determine the benefit of nasally inhaled dornase alfa in patients with cystic fibrosis and nasal symptoms. DESIGN: Double-blind placebo-controlled trial. SETTING: Cystic Fibrosis Regional Center of Campania at the University of Naples "Federico II." PATIENTS: A total of 24 patients with cystic fibrosis and chronic sinusitis. INTERVENTIONS: Patients underwent sinonasal surgery during a 3-year period and received once-daily doses of either dornase alfa (2.5 mg) or hypotonic saline solution (5 mL) beginning 1 month after surgery and for a 12-month period. MAIN OUTCOME MEASURES: Primary outcomes were nasal-related symptoms and nasal endoscopic appearance; secondary outcomes were forced expiratory volume in 1 second, nasal computed tomography findings, and saccharine clearance test results. Patients were evaluated before and after treatment. RESULTS: After surgery, all outcomes were significantly improved for each treatment at 1 month (P<.05); primary outcomes were improved at 24 and 48 weeks in the group receiving dornase alfa (P<.05), and at 12 weeks in the group receiving placebo. Secondary outcomes were better in the dornase alfa group (P<.01) than in the placebo group at 12 months except for the saccharine clearance test results. In particular, median relative difference in forced expiratory volume in 1 second between dornase alfa and placebo was significantly improved in the dornase alfa group (P<.01). CONCLUSIONS: Nasally inhaled dornase alfa can be effective in patients with cystic fibrosis and sinonasal disease who do not respond to conventional therapy after surgical treatment. Further studies should be carried out to determine the long-term effect on sinus disease, recurrence of polyps, and quality of life.  相似文献   
47.
OBJECTIVE: Hearing loss is the most common form of sensory impairment, with approximately one infant/1000 born with profound congenital deafness. A pre-lingual bilateral sensorineural hearing impairment poses a substantial problem as it negatively impacts on the subject's ability to conduct a normal social life. The aim of the study was to observe, in a group of children affected by pre-lingual non-syndromic autosomal recessive hearing impairment: (1) the role of the possible mutation of connexin 26 in the pathogenesis of the hearing loss; (2) the audiological and clinical aspects of the hearing impairment; (3) therapy to be adopted for the different patients. METHODS: The study was carried out on 39 patients, 16 males and 23 females, aged between six and 17 years (mean 12 years), affected by non syndromic congenital deafness, presumably hereditary, referred to the out-patients audiology clinic for children of the Department of Otolaryngology of the Federico II University of Naples. RESULTS: Our study conducted on 39 children with pre-lingual bilateral sensorineural autosomal recessive deafness showed as follows: (I) from a molecular perspective: an incidence of 41% in the cases studied of mutations in the encoding of the connexin 26 gene; a prevalence in our case study of the 35delG mutation (69%). (II) The characteristics of the hearing impairments in the children studied were homogeneous, regardless of the presence or absence of a connexin 26 mutation: the hearing impairment was pre-lingual bilateral sensorineural, the impairment often involved mainly the high frequencies, but, especially in the severe forms an involvement of all the frequencies was not rare; the hearing impairments were symmetrical and non progressive in time. (III) The results of the application of prosthesis and thereafter rehabilitative language therapy are generally satisfactory but correlated of course to the severity of the hearing loss. CONCLUSION: In conclusion, we hope that further developments in the research on genetic hearing impairments will promptly result in advances in clinical practice.  相似文献   
48.
Solitary brain metastases from uterine carcinoma are uncommon. Intracranial metastases from uterus usually occur in widely disseminated disease. We report three cases of solitary brain metastasis from uterine cancer. In one of these patients metastasis was detected prior to diagnosis of primitive cancer. In a review of the literature only seven cases of solitary brain metastasis preceding the diagnosis of uterine cancer have been documented.  相似文献   
49.
50.
Gastric cancer can be divided into intestinal type and diffuse type that differ substantially in epidemiology and pathogenesis. The most important aetiological factor associated both with intestinal and diffuse gastric cancer, is Helicobacter pylori. Exposure of gastric epithelial cells to H. pylori results in an inflammatory reaction with the production of reactive oxygen species and nitric oxide that, in turn, deaminates DNA causing mutations. The complex interplay between H. pylori strain, inflammation and host characteristics may directly promote diffuse type gastric cancer or induce a cascade of morphological events, i.e. atrophy, intestinal metaplasia and dysplasia, finally leading to intestinal type gastric cancer. Two mechanisms, genetic and epigenetic have been held to play a role in the molecular alterations underlying gastric carcinogenesis. The former, comprising changes in the DNA sequence, is irreversible; the latter, involving DNA methylation, is potentially reversible by eliminating the triggering agents. If H. pylori is eradicated before development of stable mutations, the risk of gastric cancer will likely be prevented. Thus, eradication of H. pylori might immediately reduce the risk of diffuse type gastric cancer, whereas prevention of intestinal type gastric cancer may be less effective if patients are treated later in the evolution of the carcinogenic process.  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