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   27077篇
  免费   1422篇
  国内免费   132篇
耳鼻咽喉   410篇
儿科学   1150篇
妇产科学   882篇
基础医学   4300篇
口腔科学   594篇
临床医学   2266篇
内科学   5420篇
皮肤病学   567篇
神经病学   2599篇
特种医学   1320篇
外国民族医学   14篇
外科学   3810篇
综合类   145篇
一般理论   3篇
预防医学   1406篇
眼科学   523篇
药学   1402篇
中国医学   22篇
肿瘤学   1798篇
  2022年   212篇
  2021年   359篇
  2020年   240篇
  2019年   331篇
  2018年   420篇
  2017年   351篇
  2016年   495篇
  2015年   480篇
  2014年   654篇
  2013年   833篇
  2012年   1191篇
  2011年   1269篇
  2010年   651篇
  2009年   722篇
  2008年   1163篇
  2007年   1280篇
  2006年   1171篇
  2005年   1198篇
  2004年   989篇
  2003年   989篇
  2002年   913篇
  2001年   922篇
  2000年   952篇
  1999年   795篇
  1998年   425篇
  1997年   336篇
  1996年   277篇
  1995年   252篇
  1994年   223篇
  1993年   222篇
  1992年   501篇
  1991年   522篇
  1990年   510篇
  1989年   439篇
  1988年   418篇
  1987年   427篇
  1986年   413篇
  1985年   409篇
  1984年   288篇
  1983年   222篇
  1982年   154篇
  1981年   152篇
  1979年   265篇
  1978年   189篇
  1977年   170篇
  1976年   165篇
  1975年   177篇
  1974年   192篇
  1973年   167篇
  1972年   155篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Ciclesonide is an onsite-activated inhaled corticosteroid (ICS) for the treatment of asthma. This study compared the efficacy, safety and effect on quality of life (QOL) of ciclesonide 160 microg (ex-actuator; nominal dose 200 microg) vs. budesonide 400 microg (nominal dose) in children with asthma. Six hundred and twenty-one children (aged 6-11 yr) with asthma were randomized to receive ciclesonide 160 microg (ex-actuator) once daily (via hydrofluoroalkane metered-dose inhaler and AeroChamber Plus spacer) or budesonide 400 microg once daily (via Turbohaler) both given in the evening for 12 wk. The primary efficacy end-point was change in forced expiratory volume in 1 s (FEV1). Additional measurements included change in daily peak expiratory flow (PEF), change in asthma symptom score sum, change in use of rescue medication, paediatric and caregiver asthma QOL questionnaire [PAQLQ(S) and PACQLQ, respectively] scores, change in body height assessed by stadiometry, change in 24-h urinary cortisol adjusted for creatinine and adverse events. Both ciclesonide and budesonide increased FEV1, morning PEF and PAQLQ(S) and PACQLQ scores, and improved asthma symptom score sums and the need for rescue medication after 12 wk vs. baseline. The non-inferiority of ciclesonide vs. budesonide was demonstrated for the change in FEV1 (95% confidence interval: -75, 10 ml, p = 0.0009, one-sided non-inferiority, per-protocol). In addition, ciclesonide and budesonide showed similar efficacy in improving asthma symptoms, morning PEF, use of rescue medication and QOL. Ciclesonide was superior to budesonide with regard to increases in body height (p = 0.003, two-sided). The effect on the hypothalamic-pituitary-adrenal axis was significantly different in favor of ciclesonide treatment (p < 0.001, one-sided). Both ciclesonide and budesonide were well tolerated. Ciclesonide 160 microg once daily and budesonide 400 microg once daily were effective in children with asthma. In addition, in children treated with ciclesonide there was significantly less reduction in body height and suppression of 24-h urinary cortisol excretion compared with children treated with budesonide after 12 wk.  相似文献   
32.
33.
34.
35.
Metastatic bone disease from occult carcinoma: a profile   总被引:3,自引:0,他引:3  
Summary To assess the general profile of metastatic bone disease from occult primary carcinoma, the records of 172 patients with skeletal metastases seen between 1965 and 1985 were reviewed. In 51 patients (30%), the origin of the primary could not be identified when bone metastases were first diagnosed. This group were predominantly male with a high incidence of spinal metastases, cord compression and pathological fractures, and a significantly shorter (P<0.1) survival compared with bony metastases when the primary was known. The site of the primary was established in 33 patients (65%), mostly at autopsy. Lung carcinoma was by far the most common primary tumour in 52% of the cases, while it accounted for only 7% of those with a diagnosed primary. We believe that the onset of bony metastases from an occult source must initially raise the possibility of lung carcinoma. If the primary remains undetected, it appears justifiable to assume it to be in the lung, since the probability of a missed lung tumour being responsible for the metastases is high.
Résumé Les auteurs ont revu les observations de 172 malades porteurs de métastases osseuses, vus entre 1965 et 1985, afin d'apprécier l'aspect général des métastases provenant d'un cancer primitif méconnu. Chez 51 malades (30%) l'origine du cancer primitif n'avait pu être découverte lors du diagnostic de métastase osseuse. Ce groupe était à prédominance masculine, comportant un nombre élevé d'atteintes vertébrales, de compressions médullaires et de fractures pathologiques, et un taux de survie significativement plus court (P<0,1) comparativement à celui des métastases d'un cancer primitif connu. La localisation du cancer primitif a été découverte dans 33 cas (65%), la plupart du temps à l'autopsie. Le cancer du poumon était le plus fréquemment en cause (52%), alors qu'il n'était responsable que de 7% des cas quand le cancer primitif était connu. Il semble que l'apparition de métastases osseuses d'origine inconnue doive faire évoquer d'emblée la possibilité d'un cancer du poumon. Si le cancer primitif ne peut être découvert il est vraisemblable qu'il siège au niveau du poumon, la probabilité d'un cancer du poumon méconnu, responsable des métastases, étant élevée.


Presented in part at the International Symposium on Bone Metastases, Rome, Italy, June 1986  相似文献   
36.
37.
Waldenstrom's macroglobulinemia (WM) is an uncommon low-grade lymphoma. Cognitive impairment due to central nervous system infiltration by lymphoplasmocytoid cells (Bing-Neel syndrome) has been rarely reported. We describe a 54-year-old man who was referred to a memory disorder clinic with a 9-month history of clinically obvious nonfluent aphasia and WM. He underwent extensive neuropsychological testing, clinical examination and structural and functional brain imaging. The diagnosis of the diffuse form of the Bing-Neel syndrome was supported by abnormal lymphoid cells found in the cerebrospinal fluid. Structural and functional brain imaging revealed impairment of brain areas due to white matter changes and subsequent functional deficits mimicking the neuropsychological syndrome encountered in progressive nonfluent aphasia. The diffuse form of Bing-Neel syndrome and neurological deficits are assumed to be the result of leptomeningeal infiltration by malignant cells and/or neoplastic vascular obstruction.  相似文献   
38.
39.
Depressive symptoms are common in patients with neurodegenerative disorders. Imaging studies suggest that a disruption of frontal-subcortical pathways may underlie depression associated with basal ganglia disease. This pilot study tested the hypothesis that frontal dysfunction contributes to depression associated with multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). Depressed patients with MSA (n = 11), PSP (n = 9), and age-matched controls (n = 25) underwent measures of cerebral glucose metabolism applying positron emission tomography with (18)F-fluorodeoxyglucose. Regional metabolism in the patient groups was compared to the normal subjects using the voxel-based statistical parametric mapping. Depressive symptom severity (Hamilton Depression Rating) and degree of locomotor disability (Hoehn & Yahr) were assessed in the patient groups. The association between prefrontal metabolism and the occurrence of depressive symptoms and the degree of locomotor disability was investigated. When compared to controls, MSA patients revealed significant metabolic decreases in bilateral frontal, parietal, and cerebellar cortex and in the left putamen. In PSP patients, significant hypometabolism was demonstrated in bilateral frontal cortex, right thalamus, and midbrain. Depression severity but not the patients' functional condition was significantly associated with dorsolateral prefrontal glucose metabolism in both patient groups. The findings of this pilot study support the hypothesis that depressive symptoms in MSA and PSP are associated with prefrontal dysfunction.  相似文献   
40.
Serosorting (i.e., engaging in unprotected sex with partners known to be of the same serostatus) can be a difficult process for men who have sex with men (MSM) who frequently make assumptions about their partners' serostatus. This process can be further complicated by a partner's dishonesty as well as other individual and contextual factors. The present study specifically examined how assumptions of serostatus made about unknown serostatus partners impact on the sexual behavior of 110 alcohol-abusing HIV-positive MSM. Although previous research has shown that HIV-positive MSM are more likely to serosort with other known HIV-positive men than with known HIV-negative men, our data suggest that unprotected sex behavior may not be specifically driven by whether or not they made assumptions of seroconcordance or serodiscordance. The types of assumptions these HIV-positive MSM made about their unknown status sexual partners and the basis for such assumptions were also examined. Owing to the ambiguities involved in assumptions of a partner's serostatus in sexual encounters, the 'unknown status' partner category is analytically distinct from 'known status' categories, and needs to be more fully explored because of its impact on perceived serosorting, rather than actual serosorting, among HIV-positive men.  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