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   11106篇
  免费   927篇
  国内免费   39篇
耳鼻咽喉   61篇
儿科学   360篇
妇产科学   288篇
基础医学   1743篇
口腔科学   119篇
临床医学   1373篇
内科学   2015篇
皮肤病学   155篇
神经病学   1261篇
特种医学   210篇
外科学   1251篇
综合类   154篇
一般理论   18篇
预防医学   1434篇
眼科学   178篇
药学   731篇
中国医学   21篇
肿瘤学   700篇
  2024年   24篇
  2023年   178篇
  2022年   279篇
  2021年   533篇
  2020年   389篇
  2019年   458篇
  2018年   441篇
  2017年   361篇
  2016年   374篇
  2015年   374篇
  2014年   474篇
  2013年   605篇
  2012年   889篇
  2011年   879篇
  2010年   455篇
  2009年   433篇
  2008年   639篇
  2007年   704篇
  2006年   616篇
  2005年   545篇
  2004年   499篇
  2003年   426篇
  2002年   378篇
  2001年   124篇
  2000年   116篇
  1999年   109篇
  1998年   85篇
  1997年   53篇
  1996年   45篇
  1995年   33篇
  1994年   32篇
  1993年   28篇
  1992年   59篇
  1991年   55篇
  1990年   38篇
  1989年   32篇
  1988年   35篇
  1987年   26篇
  1986年   27篇
  1985年   28篇
  1984年   17篇
  1983年   17篇
  1981年   9篇
  1979年   12篇
  1978年   8篇
  1977年   8篇
  1975年   8篇
  1974年   7篇
  1973年   9篇
  1965年   6篇
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
21.
Case history of a 54 yr old lady with acute viral hepatitis who developed cryptogenic organising pneumonitis. The patient was receiving corticosteroids at the time of onset of symptoms.  相似文献   
22.
23.
It is well established that the circadian clock of the suprachiasmatic nuclei (SCN) is entrained by light. More recently, the potent effects of arousing, non-photic cues on the clock have been recognized. The neural mediators of non-photic entrainment are yet to be identified. To examine the contribution of the thalamic intergeniculate leaflet (IGL) and its NPY-immunopositive projection, the geniculo-hypothalamic tract to non-photic entrainment by arousal, male Syrian hamsters received lesions of the IGL (IGLX) which ablated NPY-immunoreactivity in the SCN. Their circadian responses to both photic and non-photic cues were then tested. Lesions resulted in a delay in the timing of activity onset following lights out, but had no effect on the behavioural or cellular circadian responses to phase-advancing light pulses presented at circadian time (CT) CT19 (where CT12 represents the time of activity onset). Injection with a benzodiazepine (chlordiazepoxide, 100 mg/kg) at CT6 suppressed wheel-running, increased general locomotion of intact controls and induced large phase advances of the circadian rhythm of wheel-running. Chlordiazepoxide also inhibited wheel-running in lesioned animals, but there was no significant increase in general locomotion and the lesioned animals did not phase advance. Serial arousal by injection of saline at intervals of 23.5 h for 6 days entrained the circadian rhythm of wheel-running of intact hamsters and was associated with an increase in general locomotor activity. Entrainment by serial arousal was abolished by IGLX. However, the lesioned animals did show a clear behavioural response to every presentation of the non-photic cue. These results show that the IGL is a necessary component of the neural pathways mediating both arousal- and benzodiazepine-induced non-photic entrainment.  相似文献   
24.
本文采用小鼠精子试验和小鼠睾丸DNA合成抑制试验,检测了JX-1对雄性生殖细胞的致突变作用。实验结果表明JX-1对小鼠精子总数、精子活动率及精子畸形率均无统计学意义的增加,与小鼠睾丸DNA合成抑制试验阴性反应一致。作者认为JX-1对雄性生殖细胞为一种非诱变剂。  相似文献   
25.
26.
PURPOSE: Epilepsies in children are complex diseases. Guidelines are needed on the appropriate use of newer versus older anti-epileptic drugs (AEDs). This paper presents an individual patient-sampling model to assess the cost-effectiveness of using newer AEDs as add-on therapy in line with UK prescribing guidance. METHODS: Identification of the relevant parameters and treatment pathways for the model were achieved by a systematic review of the literature and discussions with clinical experts. Data were obtained from the literature and supplemented with data elicited from paediatric neurologists. The model considered paediatric patients over the period of childhood from the age of diagnosis to 18 years. RESULTS: The results suggest that the older and newer AEDs are similar in terms of drug retention rates and the average time in 'good' treatment outcomes. In terms of cost, the results indicate a consistent increase in cost (compared to older AEDs) when all of the newer AEDs are considered. The decision analysis results indicate that there are no important health benefits from the use of newer AEDs when used as add-on therapy. However, the analysis also reveals that the uncertainties in the model are greater than the differences between the drug strategies. CONCLUSIONS: To develop guidelines on the appropriate use of newer AEDs, better information is required from randomised controlled trials as there is insufficient data available in the public domain to accurately estimate the nature of the trade off between older versus newer AEDs.  相似文献   
27.

Background  

The aim of the current study is to investigate the relationship between physical anhedonia and psychopathological parameters, pharmacological parameters or motor side-effects in a sample of inpatients with schizophrenia in an acute episode of their illness.  相似文献   
28.
BACKGROUND: Previous structural magnetic resonance (MR) research in patients with posttraumatic stress disorder (PTSD) has found smaller hippocampal volumes in patients compared with control subjects. These studies have mostly involved subjects who have had PTSD for a number of years, such as war veterans or adult survivors of childhood abuse. Patients with recent-onset PTSD have rarely been investigated. To our knowledge only one other study has investigated such a group. The aim of this study was to compare hippocampal volumes of patients with recent onset PTSD and nontrauma-exposed control subjects. METHODS: Fifteen patients with PTSD, recruited from an accident and emergency department, were compared with 11, non-trauma-exposed, healthy control subjects. Patients underwent a structural MR scan soon after trauma (mean time = 158 +/- 41 days). Entire brain volumes, voxel size 1 x 1 x 1 mm, were acquired for each subject. Point counting and stereology were used to measure the hippocampal and amygdala volume of each subject. RESULTS: Right-sided hippocampal volume was significantly smaller in PTSD patients than control subjects after controlling for effects of whole brain volume and age. Neither left nor total hippocampal volume were significantly smaller in the PTSD group after correction. Whole brain volume was also found to be significantly smaller in patients. There were no differences in amygdala or white matter volumes between patients and control subjects. CONCLUSIONS: This result replicates previous findings of smaller hippocampal volumes in PTSD patients, but in an underinvestigated population, suggesting that either smaller hippocampal volume is a predisposing factor in the development of PTSD or that damage occurs within months of trauma, rather than a number of years. Either of these two hypotheses have significant implications for the treatment of PTSD. For instance, if it could be shown that screening for hippocampal volume may, in some cases, predict those likely to develop clinical PTSD.  相似文献   
29.
Nodular regenerative hyperplasia (NRH), a rare condition that is commonly associated with noncirrhotic portal hypertension, is not well described in the MR literature. Three patients at two institutions were identified who had both abdominal MR imaging and pathologic evidence of NRH. All examinations were performed at 1.5 T and included axial T1- and T2-weighted spin-echo (SE) images. The MR studies were reviewed by two radiologists in consensus. Two patients had multiple liver lesions that had high signal components on T1-weighted images and were predominantly isointense with liver on the T2-weighted images. One patient had no focal lesions identified. NRH, when visualized on MR images, appears as multifocal masses with shortened Tl and T2 similar to liver. NRH should be considered in the differential diagnosis of hepatocellular tumors, especially in patients with a predisposing condition.  相似文献   
30.
Limbal xanthogranuloma   总被引:3,自引:0,他引:3  
Three cases of histologically proven limbal xanthogranuloma are presented. All three cases presented with a yellow raised swelling at the limbus and no other ocular or systemic abnormality. A simple excision of the lesion was carried out in all cases and histological examination revealed features typical of xanthogranuloma. Two patients had a recurrence at the original site, necessitating keratectomy, with insertion of a lamellar graft. We suggest that a primary keratectomy with insertion of a lamellar graft should be performed in cases of limbal xanthogranuloma in order to lessen the risk of recurrence and to provide a better cosmetic result.  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