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   1925篇
  免费   118篇
  国内免费   24篇
耳鼻咽喉   13篇
儿科学   53篇
妇产科学   84篇
基础医学   208篇
口腔科学   16篇
临床医学   140篇
内科学   662篇
皮肤病学   36篇
神经病学   229篇
特种医学   27篇
外科学   136篇
综合类   2篇
预防医学   103篇
眼科学   6篇
药学   120篇
中国医学   5篇
肿瘤学   227篇
  2024年   3篇
  2023年   12篇
  2022年   36篇
  2021年   77篇
  2020年   45篇
  2019年   51篇
  2018年   63篇
  2017年   56篇
  2016年   64篇
  2015年   69篇
  2014年   83篇
  2013年   114篇
  2012年   151篇
  2011年   150篇
  2010年   54篇
  2009年   78篇
  2008年   146篇
  2007年   128篇
  2006年   121篇
  2005年   111篇
  2004年   125篇
  2003年   104篇
  2002年   102篇
  2001年   16篇
  2000年   7篇
  1999年   9篇
  1998年   13篇
  1997年   11篇
  1996年   12篇
  1995年   11篇
  1994年   5篇
  1993年   4篇
  1992年   5篇
  1991年   6篇
  1990年   5篇
  1989年   4篇
  1988年   3篇
  1987年   1篇
  1986年   2篇
  1984年   1篇
  1983年   3篇
  1978年   1篇
  1977年   1篇
  1975年   2篇
  1974年   1篇
  1973年   1篇
排序方式: 共有2067条查询结果,搜索用时 15 毫秒
101.
Neonatal seizures associated with white-matter changes on neuroimaging suggest an etiology of hypoxic-ischemic encephalopathy. Metabolic and idiopathic etiologies are also considerations but are less likely. Despite the fact that two disorders associated with neonatal seizures are diagnosed by cerebrospinal fluid neurotransmitter analysis, such an analysis is not standard in the work-up for idiopathic neonatal seizures. We describe an infant who had a prolonged delivery, seizures on the first day of life, and white-matter changes on neuroimaging. A progressive seizure disorder that was refractory to standard antiepilepsy medications developed at 2 months of age. Analysis of cerebrospinal fluid neurotransmitters at that time demonstrated a pattern consistent with folinic acid-responsive seizures. Seizures ceased 24 hours after starting folinic acid. Serial neuroimaging, electroencephalograms, and metabolic changes from this patient are presented. This case illustrates the importance of cerebrospinal fluid neurotransmitter analysis as part of the work-up for idiopathic neonatal seizures.  相似文献   
102.
Temporary threshold shift (TTS) and permanent threshold shift (PTS) may follow prolonged noise exposure. Several reports suggest that noise-induced damage to the cochlea may be related to the activity of reactive oxygen species (ROS). Drugs that scavenge or block ROS formation also protect the cochlea. Guinea pigs, treated with allopurinol, were exposed to white noise (120 dB SPL) or impulse noise (114 dB SPL) for 2 and 5 h. The protective effect of allopurinol was confirmed, but, at these levels of sound, it was present only after noise exposure up to 2 h. This study also offers evidence suggesting that allopurinol does not influence the establishment of PTS.  相似文献   
103.
Gastrointestinal infections represent one of the main cause of morbidity both in developing and industrialized areas. Quality of coastal waters is particularly important for countries as Italy that has several regions on coasts. Public health and economy aspects could be hardly affected by poor quality of sea waters. Several studies have been addressed to the association between sea recreational water and development of gastrointestinal infection but in Italy only sporadic cases of infection have been reported especially in immunocompromised hosts. Results of this study, either in the case control or in the active surveillance study seem to confirm the absence of an association between sea exposure and intestinal infections. One of the main risk factors for the development of these infections is still represented by the seafood consumption especially shellfish.  相似文献   
104.
Cushing's disease (CD), the chronic endogenous hypercortisolism derived from an ACTH-secreting pituitary adenoma, and multiple osteochondromatosis (MO), a congenital mesoderm dyschondroplasia, represent two distinct rare neoplastic diseases. Clinical appearance of MO usually occurs during the first-second decade of life. In fact, the growth of osteochondromas parallels the patient's growth, then becoming quiescent after the closure of the epiphyses and the achievement of final stature. Here we describe an uncommon case of a patient with a long-term history of childhood-onset CD, who surprisingly developed MO during the third decade of life, after the remission of CD. Indeed, a female patient had been followed for CD from the age of 12 to the age of 24 years, when CD definitively remitted. At the age of 26 the patient complained progressively worsening backache and pain at level of hips and feet. Standard radiography of skeleton showed multiple bone dysmorphisms at level of the four limbs, spine and pelvis consistent with multiple osteochondromas and exostoses. A diagnosis of MO was performed. Total body bone scintigraphy with 99mTc-MDP revealed an increased uptake of the radioligand, suggesting an increased metabolic turnover in correspondence of the majority of the osteochondromas. However, the negativity of the majority of the lesions at 99mTc-DMSA scintigraphy and the histological diagnosis of benign osteochondroma of the only positive lesion at 99mTc-DMSA evidenced that the high metabolic activity of the osteochondromas was not due to malignant transformation. However, the activity of the lesions was highly surprising considering that they usually become quiescent after the achievement of the final stature. In last analysis, the uncommon characteristics of MO and, particularly, its occurrence after stable remission of hypercortisolism, suggests a possible role of glucocorticoids in influencing the clinical course of the skeletal disease. The inhibitory effect of hypercortisolism on bone growth and maturation could explain the block in the proliferation of skeletal lesions during the developmental age, where CD was in the active phase, and the opposite effect of stimulation of the ostochondromas growth during stable normalization of cortisol secretion, after CD remission.  相似文献   
105.
The clinical and research debate on the peripheral intravascular (PIV) catheter length of stay in situ is ongoing. The principal aim of this study was to explore the factors behind a nurse's decision to leave a PIV in place for more than 96 hours. The study focused on 7 northern Italian hospitals in 2009. A consequent sample of 269 PIV catheters was included. Direct observation and interviews were adopted. The time of the expected PIV replacement was fixed at 96 hours after its positioning, in accordance with the international guideline. Several factors were taken into account in regard to replacement of the PIV catheters by nurses, ranging from analysis based on their own clinical experience with PIV complications and analysis of the patient's clinical situation to the critical analysis of their own work situation. This clinical decision-making process is valuable: leaving the PIV in place for more than 96 hours is a complex decision and not simply a guideline violation.  相似文献   
106.
107.
OBJECTIVE: In 1994 we mailed questionnaires to referral centers in Italy in order to evaluate the different opinions concerning aspects of endometrial cancer treatment, which is still controversial. The data processing showed a significant nonhomogeneity in disease management and prompted the Italian Society of Gynecologic Oncology to define guidelines for endometrial cancer adjuvant treatment. In 2001, we mailed again the same questionnaire to the same referral Centers in Italy. The aim of the second enquiry was the evaluation of changes in endometrial cancer management and the effective impact of the guidelines published. METHODS: The enquiry used the same questionnaires mailed in 1994; actually, we mailed those questionnaires to the same referral centers in Italy twice: in December 2000 and March 2001.The results of both the enquiries were collected in a relational data base, and the statistical evaluations were calculated using SPSS-statistics (Window ver. 8). RESULTS: Endometrial cancer treatment consists in abdominal hysterectomy and bilateral salpingo-oophorectomy. The unique relevant difference as to 1994 consists in the systemic performing of peritoneal cytology in endometrial cancer staging. Unlike the previous enquiry, adjuvant radiotherapy is not systematically performed in disease at stage Ic because of the substantial absence of confirmed data demonstrating a real benefit in terms of survival rate.The comparison between the two enquiries shows a significant change in medical planning and diversification attitude according to patient age and menopausal state. The disease management changes in patients over 75 years old, mainly with respect to surgery and primary therapy. CONCLUSIONS: We noted a resistance of many centers to accept some trends actually widespread in the literature but not yet performed in practical clinical.  相似文献   
108.
Purpose

Traumatic brain injury (TBI) is one of the most common causes of mortality and long-term disability and it is associated with an increased prevalence of neuroendocrine dysfunctions. Post-traumatic hypopituitarism (PTHP) results in major physical, psychological and social consequences leading to impaired quality of life. PTHP can occur at any time after traumatic event, evolving through various ways and degrees of deficit, requiring appropriate screening for early detection and treatment. Although the PTHP pathophysiology remains to be elucitated, on the basis of proposed hypotheses it seems to be the result of combined pathological processes, with a possible role played by hypothalamic–pituitary autoimmunity (HPA). This review is aimed at focusing on this possible role in the development of PTHP and its potential clinical consequences, on the basis of the data so far appeared in the literature and of some results of personal studies on this issue.

Methods

Scrutinizing the data so far appeared in literature on this topic, we have found only few studies evaluating the autoimmune pattern in affected patients, searching in particular for antipituitary and antihypothalamus autoantibodies (APA and AHA, respectively) by simple indirect immunofluorescence.

Results

The presence of APA and/or AHA at high titers was associated with an increased risk of onset/persistence of PTHP.

Conclusions

HPA seems to contribute to TBI-induced pituitary damage and related PTHP. However, further prospective studies in a larger cohort of patients are needed to define etiopathogenic and diagnostic role of APA/AHA in development of post-traumatic hypothalamic/pituitary dysfunctions after a TBI.

  相似文献   
109.
Sleep has a significant impact on the daily functioning of children and their parents. The purpose of this study was to describe the sleep patterns, issues, and strategies used to facilitate sleep in children with and without physical disabilities and their families. Data were collected from questionnaires completed by caregivers and siblings. Caregivers of children with physical disabilities reported significantly greater concerns regarding general sleep problems, safety, and discomfort at night, night wakening, daytime irritability, interference with daytime activities and sleep-related health concerns in children with physical disabilities than in their counterparts. Caregivers, but not siblings, in families of children with physical disabilities experienced an increased prevalence of sleep issues. The most frequently cited strategies to alleviate problems were the establishment of consistent routines and provision of calming, supportive sleep environments. Pediatric therapists need to assess and address sleep issues to promote the well-being of children and their families.  相似文献   
110.
IntroductionThere are only a few studies on the frequency of sexual desire in the general population, whereas studies investigating the frequency of disordered sexual desire are more common.AimThe aim of this study was to describe the frequency of sexual desire in a representative sample of the adult Danish population and to analyze the relationships between a number of relevant variables and sexual desire.MethodsThe study population (N = 10,458, response rate 84.8%) answered a questionnaire with questions on sexual matters. The representativity of the population was examined. The frequency of self‐reported sexual desire and decrease in sexual desire over a 5‐year period was calculated for the two genders across age cohorts. Multiple logistic regression analysis was used to analyze the relationship between potential determinants and sexual desire.Main Outcome MeasuresThe frequency of self‐reported sexual desire and decrease in sexual desire was examined. Factors of importance for sexual desire were tested using two outcome measures: (i) often having sexual desire; and (ii) seldom having sexual desire.ResultsA significant association between gender and sexual desire was found in all age groups, as men had a significantly higher level of sexual desire than women. In both genders, the frequency of sexual desire was significantly reduced with increasing age. Among the 45‐ to 66‐year‐olds, 57% of the men and 47% of the women reported no change in the level of sexual desire over the past 5 years. In general terms, factors related to seldom having sexual desire were age and social, psychological, and physical distress in both genders.ConclusionThis study shows that overall, men have a higher level of sexual desire than women; sexual desire decreases with increasing age; and social, psychological, or physical distress are associated with low level of sexual desire in both genders. Eplov L, Giraldi A, Davidsen M, Garde K, and Kamper‐Jørgensen F. Sexual desire in a nationally representative Danish population. J Sex Med 2007;4:47–56.  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