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   405篇
  免费   41篇
  国内免费   1篇
耳鼻咽喉   4篇
儿科学   15篇
妇产科学   11篇
基础医学   33篇
口腔科学   3篇
临床医学   39篇
内科学   53篇
皮肤病学   24篇
神经病学   31篇
特种医学   35篇
外科学   73篇
综合类   3篇
预防医学   15篇
眼科学   16篇
药学   40篇
中国医学   1篇
肿瘤学   51篇
  2023年   5篇
  2022年   6篇
  2021年   9篇
  2020年   9篇
  2019年   13篇
  2018年   15篇
  2017年   9篇
  2016年   13篇
  2015年   7篇
  2014年   18篇
  2013年   24篇
  2012年   24篇
  2011年   25篇
  2010年   13篇
  2009年   14篇
  2008年   27篇
  2007年   22篇
  2006年   22篇
  2005年   23篇
  2004年   30篇
  2003年   22篇
  2002年   16篇
  2001年   6篇
  2000年   4篇
  1999年   2篇
  1998年   5篇
  1997年   7篇
  1996年   6篇
  1995年   2篇
  1994年   1篇
  1993年   3篇
  1991年   2篇
  1990年   3篇
  1989年   3篇
  1988年   2篇
  1987年   2篇
  1985年   1篇
  1984年   3篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1978年   1篇
  1977年   6篇
  1976年   6篇
  1975年   4篇
  1974年   2篇
  1972年   2篇
  1968年   1篇
  1966年   2篇
  1935年   1篇
排序方式: 共有447条查询结果,搜索用时 31 毫秒
1.
Osteoporosis is a condition in which the bones are thinner and more liable to fracture. It is commoner in women and in people over 50. It cannot be cured so the focus is on prevention, which means identifying and addressing risk factors such as obesity, low vitamin D, chronic inflammation and prolonged steroid medication. Chronic urticaria (hives, CU) is an inflammatory condition, so one might expect it to be linked with osteoporosis, but that has never been investigated. If people with CU are indeed more likely to develop osteoporosis, they could be advised about preventative measures. To study this, doctors from Israel identified 11,944 patients diagnosed with CU in a large medical database covering 4.5 million people. A potential difficulty was that people with CU are more likely to be female, obese and to have been treated with systemic steroids, all of which also increase the risk of osteoporosis. Therefore for each CU patient they studied 5 age- and sex-matched control patients (people of the same age and sex but without CU) and their analyses took into account other known risk factors for osteoporosis. During a 16 year period 8.7% of the patients with CU were diagnosed with osteoporosis compared with 6.8% of the controls. They concluded that CU is a small but significant additional risk factor for osteoporosis. An accompanying editorial cautions against basing conclusions on routine health records which may not have all the information required. Nonetheless, doctors treating chronic urticaria might bear in mind the risk of osteoporosis in their patients, and counsel accordingly.  相似文献   
2.
Cerebellar involvement in motor and non-motor sequence learning was examined with serial reaction time tasks (SRT). Our sample consisted of 8 children and adolescents who had undergone surgical removal of a benign posterior fossa tumor (PFT) during childhood. None of them had undergone chemotherapy or cranial radiation therapy (CRT). Ages ranged from 1-11 years at surgery and 9-17 years at testing. The children were tested not earlier than 2.5 years after surgery (M = 5.9 years), enabling brain plasticity and recovery of functions. Their performance was compared with a matched control sample. The PFT group was not impaired in the implicit learning of sequences, as reflected in their performance in blocks with a repeated sequence, both before and after a random block. However, in the perceptual task, their performance deteriorated more than that of the control group when a random block was introduced, suggesting that it was more difficult for the patients to respond flexibly or change their response set when encountering changing task demands. These results are in line with another study by our group on task switching with the same patients.  相似文献   
3.
4.
Vibrio vulnificus may cause severe soft tissue infections of the upper extremity. This pathogen usually gains access to soft tissues either by direct inoculation through a penetrating injury by an infected marine animal or by exposing abraded skin to contaminated water. We report five patients with Vibrio vulnificus hand infections following superficial hand injuries incurred within 24 hours after uneventful handling of fish. This clinical observation, together with the fact that the physiologic characteristics of human sweat simulate the natural environment of the Vibrio vulnificus, support the assumption that human skin may serve as a reservoir for Vibrios. The anamnesis in patients presenting with hand infection should essentially include an inquiry regarding recent, albeit uneventful, fish handling.  相似文献   
5.
Three patterns of activity were evident when the differential activation of the DNA polymerase associated with serum Dane particles by nonionic detergent and salt was investigated. The patterns were obtained by plotting the increase in enzyme activity mediated by the detergent Nonidet P-40 (NP-40) in increasing concentrations of KCl compared to the activity observed in the absence of detergent. The pattern of differential activity of hepatitis B (HB) DNA polymerase in detergent and salt was altered by subjecting the HBAg preparations to shearing forces. Hepatitis B DNA polymerase activity was stable even in NP-40 concentrations as high as 10%. In addition to hepatitis B DNA polymerase, DNA polymerase activated by calf thymus DNA was found in pellets containing Dane particles. The latter DNA polymerase activity was also activated by NP-40 and was not decreased by DNAse; this DNA polymerase coprecipitated with hepatitis B antigen (HBAg) upon addition of anti-HBs. However, the DNA polymerase activated by calf thymus DNA was inhibited by 0.4 M KCl. Electron microscopic observations of serum Dane particles in 0.4 M KCl showed no alterations of morphology of these particles when compared to particles in low-salt buffer. The data indicated that KCl activated HB DNA polymerase by a different mechanism from that of shear or NP-40, which removed the surface antigen coat from the Dane particles.  相似文献   
6.
Accepted 12 September 1996
OBJECTIVE—Our experience in children with visual pathway glioma (VPG) was reviewed to delineate its clinical characteristics.
DESIGN—The charts and imaging studies of 21 children with VPG who were followed up in our centre during the last 12 years were reviewed and summarised.
RESULTS—VPG accounted for 13.1% of all brain tumours treated during this period. Sixty two per cent of the children with VPG had neurofibromatosis type 1 (NF-1). Among these, more than 60% were detected as part of routine work up. In some cases decreasing visual function preceded the appearance of the VPG on imaging studies. Tumour growth rate was markedly unpredictable. All treatment modalities employed led to tumour shrinkage and stabilisation for a variable period, but none was successful in totally eradicating the tumour. Complications were less severe after chemotherapy compared with radiotherapy. Three children died, none with NF-1, with a globular hypothalamic/chiasmatic tumour and accompanying electrolyte abnormalities.
CONCLUSIONS—NF-1 is a favourable prognostic marker for VPG. Whenever possible a period of observation is necessary before treatment is initiated, during which time tumour size and visual function should be closely followed up; an untoward change in either of these is an indication for the start of treatment, preferably chemotherapy first. The combination of a globular hypothalamic/chiasmatic glioma and electrolyte abnormalities in a child without NF-1 are related to a poor prognosis.

  相似文献   
7.
Hyperuricemia is present in approximately 5% of the population. The vast majority is asymptomatic and at no clinical risk. Allopurinol, an analog of hypoxanthine, has been widely used in clinical practice for more than 30 years for the treatment of hyperuricemia and gout. Two percent of patients develop a mild exanthema when on this drug, which usually resolves after withdrawal of the drug. A syndrome characterized by exfoliative dermatitis, hepatitis, interstitial nephritis, and eosinophilia, termed allopurinol hypersensitivity syndrome, has been described, and its etiology related to the accumulation of one of allopurinol's metabolites, oxypurinol, of which clearance is decreased in the setting of renal insufficiency and the use of thiazide diuretics. The term DRESS (Drug Rash with Eosinophilia and Systemic Symptoms) Syndrome has been recently used to describe an entity presenting with similar features.  相似文献   
8.
9.
Purpose: To examine the effects of hyperbaric oxygen (HBO) therapy and knockout of toll-like receptor 4 (TLR4) on the outcome of temporary middle cerebral artery occlusion (MCAO) in a mouse model. Materials and Methods: MCAO was induced in anesthetized male C57Bl/6 mice (WT) and TLR4 knockout mice (TLR4?/?) using an intra-arterial filament method. After 30 or 90 min, the filament was removed, and the mice were given either no treatment (WT and TLR4?/- groups) or HBO (WT only). Mice were euthanized 24 h after MCAO, and the brain infarct area was examined using 2,3,5-triphenyltetrazolium chloride (TTC) staining. Results: In the WT group, without treatment, lesion volume was 120 ± 13 mm3 in the mice subjected to 30 min’ MCAO and 173 ± 23 mm3 in the mice subjected to 90 min’ MCAO. Respective values with HBO treatment were 66.5 ± 36.7 mm3 and 53.2 ± 17.2 mm3. The difference was significant only for 90-minute MCAO (p < 0.01, nonparametric test). In the TLR4?/? group (all untreated), lesion volume was 95.9 ± 17.9 after 90 min of MCAO, which was significantly lower than in the untreated WT animals (p < 0.05, nonparametric test). Conclusions: A single treatment of HBO immediately after MCAO followed by 24 h’ reperfusion significantly reduces edema and may improve perfusion. TLR4 knockout protects mice from MCAO damage, but to a lesser extent than HBO treatment.  相似文献   
10.
The authors evaluated the impact of hydrocephalus on the clinical picture of children with visua pathway tumor (VPT) with or without neurofibromatosis (NF).Charts of children with VPT treated in the authors' center since 1985 were retrospectively reviewed, and those with hydrocephalus were selected and summarized. Thirty-five children with VPT were found, of whom 20 had NF.Hydrocephalus was found in 4 children with NF (20% ) and in 5 without NF (33.3% ). In 6 ofthechildren, ventricular dilatation with signs of acute increased intracranial pressure already existed at the time of diagnosis and the hydrocephalus was shunted at this time. In the other 3 children, all with NF,the hydrocephalus resulted from slowly developing aqueductal stenosis, leading in 2 to severe visual acuity deterioration. The results suggest that in children with VPT and NF, hydrocephalus, and especially hydrocephalus resulting from aqueductal stenosis, is more frequent than in the general population of NF patients, and less frequent than in VPT patients without NF. The possibility of the indolent development of hydrocephalus should be borne in mind while following children with NF. The optic nerve, when already involved with a glioma, is more vulnerable to increased pressure. Thus, in children with VPT and NF, any ventricular dilatation should lead to a consideration of early shunting.  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