全文获取类型
收费全文 | 37295篇 |
免费 | 2109篇 |
国内免费 | 169篇 |
专业分类
耳鼻咽喉 | 538篇 |
儿科学 | 951篇 |
妇产科学 | 849篇 |
基础医学 | 5057篇 |
口腔科学 | 3216篇 |
临床医学 | 2891篇 |
内科学 | 7865篇 |
皮肤病学 | 922篇 |
神经病学 | 3050篇 |
特种医学 | 692篇 |
外国民族医学 | 2篇 |
外科学 | 3982篇 |
综合类 | 260篇 |
一般理论 | 4篇 |
预防医学 | 4471篇 |
眼科学 | 565篇 |
药学 | 2387篇 |
中国医学 | 308篇 |
肿瘤学 | 1563篇 |
出版年
2023年 | 364篇 |
2022年 | 846篇 |
2021年 | 1496篇 |
2020年 | 982篇 |
2019年 | 1288篇 |
2018年 | 1493篇 |
2017年 | 1031篇 |
2016年 | 1115篇 |
2015年 | 1311篇 |
2014年 | 1706篇 |
2013年 | 2026篇 |
2012年 | 2998篇 |
2011年 | 3160篇 |
2010年 | 1622篇 |
2009年 | 1209篇 |
2008年 | 2134篇 |
2007年 | 2184篇 |
2006年 | 1688篇 |
2005年 | 1619篇 |
2004年 | 1415篇 |
2003年 | 1308篇 |
2002年 | 1052篇 |
2001年 | 656篇 |
2000年 | 651篇 |
1999年 | 537篇 |
1998年 | 203篇 |
1997年 | 128篇 |
1996年 | 83篇 |
1995年 | 102篇 |
1994年 | 109篇 |
1993年 | 79篇 |
1992年 | 285篇 |
1991年 | 247篇 |
1990年 | 241篇 |
1989年 | 205篇 |
1988年 | 185篇 |
1987年 | 126篇 |
1986年 | 149篇 |
1985年 | 140篇 |
1984年 | 88篇 |
1983年 | 76篇 |
1979年 | 98篇 |
1978年 | 76篇 |
1974年 | 67篇 |
1973年 | 68篇 |
1970年 | 79篇 |
1969年 | 92篇 |
1968年 | 69篇 |
1967年 | 79篇 |
1966年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Marcondes C Fran?a Maria E Calcagnotto Jaderson C da Costa Iscia Lopes-Cendes 《Movement disorders》2006,21(7):1051-1053
Spinocerebellar ataxia (SCA) types 2 and 3 are autosomal-dominant neurodegenerative disorders caused by mutations in two different genes. We identified mutations for SCA2 and SCA3 segregating simultaneously in a single Brazilian family. The index patient had SCA2, whereas her two second-degree cousins had SCA3. Disease was more rapidly progressive in the SCA2 patient, who presented severe brainstem and pancerebellar atrophy, as opposed to the two SCA3 patients, who had only mild cerebellar vermian atrophy. In such situations, molecular confirmation of all patients may avoid misdiagnosis of SCA subtypes and eventual errors in predictive testing of unaffected family members. 相似文献
3.
Mariela Dutra Gontijo Moura Soraya de Mattos Camargo Grossmann Linaena Méricy da Silva Fonseca Maria Inês Barreiros Senna Ricardo Alves Mesquita 《Journal of oral pathology & medicine》2006,35(6):321-326
BACKGROUND: Oral hairy leukoplakia (OHL) may be an indicator of the progression of Human Immunodeficiency Virus (HIV)-induced immuno-depression, and the evaluation of risk factors leading to OHL is important in the management of these HIV-infected patients. However, there are few studies that analyze risk factors leading to OHL in the Brazilian population. The aim of this case-control study is to present data about prevalence rates and risk factors leading to OHL in a sample of HIV-infected adults in Brazil. METHODS: This case-control study included 111 HIV-infected patients treated at a clinic for sexually transmitted diseases and HIV. In the initial examinations with dentists, variables were collected from all patients. Diagnosis of OHL was performed in accordance with the International Classification System and cytological features. The Fisher and the chi-squared tests were used for statistical analysis. The proportional prevalence and odds ratio were estimated. RESULTS: Outcome presented a positive, statistically significant association among the presence of OHL and viral load of 3000 copies/mul or greater (P = 0.0001; odds ratio (OR) = 5.8), presence of oral candidiasis (P = 0.0000; OR = 11.1), previous use of fluconazole (P = 0.0000; OR = 24.6), and use of systemic acyclovir (P = 0.032; OR = 4.3). Antiretroviral medication presented a negative, statistically significant association with the presence of OHL (P = 0.002; OR = 8.4). CONCLUSIONS: Prevalence of OHL was 28.8%. Viral load, oral candidiasis, previous use of fluconazole, and systemic acyclovir were determined to be risk factors for OHL. Antiretroviral medication proved to be protective against the development of OHL. 相似文献
4.
Jorge Guardado Carlos Cotrim Otília Sim?es Sofia Almeida Mário Ialá Luís Lopes Hélder Pereira Manuel Carrageta 《Revista portuguesa de cardiologia》2006,25(4):409-415
INTRODUCTION: Transesophageal echocardiography (TEE) has become increasingly useful in the study of patients with suspected pulmonary thromboembolism. OBJECTIVE: The aim of this study was to prospectively evaluate the usefulness of TEE in the study of the distal part of the left pulmonary artery (LPA) as well as the influence of this procedure on total echocardiographic exam duration. METHODOLOGY: A prospective study in two groups of consecutive patients referred for TEE with a one- year interval between evaluation of Group A: 33 patients, 17 male, mean age 54 +/- 24 years, and Group B: 42 patients, 20 male, mean age 48 +/- 27 years (p = NS). The procedure was considered long when it took more than 3 min to evaluate the distal part of the LPA. RESULTS: In group A we were able to visualize the distal part of the LPA in 24 patients (73%) without significant prolongation of total exam duration in 16 patients (48% of group A). In one of the patients with suspected pulmonary thromboembolism thrombi were only observed in the distal part of the LPA. In group B we were able to visualize the distal part of the LPA in 36 patients (86%) without significant prolongation of total exam duration in 26 patients (61% of group B). CONCLUSIONS: 1. Visualization of the distal part of the LPA was possible in more patients, and with TEE time prolongation in less patients, in group B. These differences can be accounted for by the training of the operator in this technique. 2. The importance of visualization of this part of the LPA in guiding treatment in the subset of patients with pulmonary thromboembolism confirms the usefulness of this specific procedure. 相似文献
5.
6.
7.
8.
A 16-year-old boy, the only affected member of the family, noticed early onset contracture of the elbows, and developed slowly progressive humeroperoneal weakness and atrophy, and bilateral equinus. The severe restriction of the forward flexion of the neck and thoracolumbar spine, resembled a rigid spine syndrome. An electrocardiogram showed atrioventricular conduction abnormalities. Muscle biopsy was consistent with mild myopathy. The overall conventional findings of a detailed electromyographic study in the limbs and erector trunci muscles, as well as the results of conduction velocity, automatic analysis of the voluntary pattern and single fiber electromyography studies were consistent with myopathy, although some atypical findings were found. The controversy about neurogenic and myopathic features in Emery-Dreifuss disease is discussed. The unspecific value of the flexion limitation of the spine, and the uncertain nosological position of the rigid spine syndrome are also commented. 相似文献
9.
A C Da Rosa B Kemp T Paiva F H Lopes da Silva H A Kamphuisen 《Electroencephalography and clinical neurophysiology》1991,78(1):71-79
A model of sleep phasic events such as vertex waves, K complexes, delta waves and sleep spindles is proposed. It consists of feedback loops that are driven by white noise (simulating tonic delta and sigma activity) and by isolated random impulses, simulating vertex waves or K complexes, depending on the background tonic activity. A model-based method for the detection of sleep phasic events was implemented in a personal computer. Its performance was investigated using simulated and real whole-night EEG signals. The method was able to detect K complexes and vertex waves in a reliable way in spite of their variable shapes and in the presence of a variety of background activities. The detector appears to have superior performance to those so far reported in the literature. The performance of the detector was also compared to that of an electroencephalographer using normal sleep EEG records of 8 h duration from 6 subjects. The performance was satisfactory both in terms of accuracy and reliability. The problem of detecting K complexes in stages 3 and 4 of sleep is discussed. 相似文献
10.
E Gadelha Figueiredo M Castillo De la Cruz N Theodore P Deshmukh M C Preul 《Minimally invasive neurosurgery》2006,49(1):37-42
We describe a modified keyhole laminoforaminotomy (LF) using anatomic landmarks on the posterior aspect of the cervical vertebral body to decompress the intervertebral foramen with minimal bone removal. Twenty-four procedures were performed at C3-4, C4-5, and C5-6; 12 at C6-7; and 3 at C7-Tl. Facets and laminae structures were identified based on relative surgical perspectives. Bony resection was limited as follows: 1) inferior limit; inferior border of the superior facet; 2) superior limit, superior border of the superior facet; 3) lateral limit, a vertical line linking the junction of the lamina-facet to the lateral end of the superior limit; and 4) lateral aspect of the dural sac. Fluoroscopy was used to confirm that the intervertebral space was reached. The amount of bony removal was quantified for the superior and inferior laminae and facets. The length of the exposed nerve root was measured. The intervertebral foramen was exposed and the intervertebral disc reached in all specimens. Fluoroscopy showed that the center of the exposure remained at the same height with the intervertebral space. The mean length of the nerve root was 4.6 mm; the mean percentage of bony resection was 21.8%, 7.5%, 11.3%, and 11.5% for the superior and inferior laminae and facets, respectively. Opening the intervertebral foramen posteriorly consistently exposed sufficient nerve root length and allowed access to the intervertebral disc. The technique offers the most direct and safest method of decompressing the intervertebral foramen while minimizing bony resection. This simple surgical procedure may help reduce postoperative morbidity. 相似文献