全文获取类型
收费全文 | 1509篇 |
免费 | 120篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 98篇 |
妇产科学 | 59篇 |
基础医学 | 213篇 |
口腔科学 | 10篇 |
临床医学 | 91篇 |
内科学 | 312篇 |
皮肤病学 | 46篇 |
神经病学 | 209篇 |
特种医学 | 28篇 |
外科学 | 208篇 |
综合类 | 26篇 |
预防医学 | 107篇 |
眼科学 | 103篇 |
药学 | 67篇 |
中国医学 | 2篇 |
肿瘤学 | 48篇 |
出版年
2021年 | 20篇 |
2020年 | 13篇 |
2019年 | 26篇 |
2018年 | 29篇 |
2017年 | 15篇 |
2016年 | 21篇 |
2015年 | 23篇 |
2014年 | 19篇 |
2013年 | 35篇 |
2012年 | 72篇 |
2011年 | 63篇 |
2010年 | 29篇 |
2009年 | 31篇 |
2008年 | 65篇 |
2007年 | 66篇 |
2006年 | 71篇 |
2005年 | 63篇 |
2004年 | 65篇 |
2003年 | 51篇 |
2002年 | 43篇 |
2001年 | 52篇 |
2000年 | 45篇 |
1999年 | 42篇 |
1998年 | 17篇 |
1996年 | 13篇 |
1995年 | 18篇 |
1993年 | 11篇 |
1992年 | 33篇 |
1991年 | 22篇 |
1990年 | 42篇 |
1989年 | 32篇 |
1988年 | 30篇 |
1987年 | 26篇 |
1986年 | 15篇 |
1985年 | 24篇 |
1984年 | 21篇 |
1983年 | 16篇 |
1982年 | 19篇 |
1980年 | 11篇 |
1979年 | 27篇 |
1978年 | 13篇 |
1977年 | 17篇 |
1976年 | 20篇 |
1975年 | 18篇 |
1974年 | 16篇 |
1973年 | 21篇 |
1971年 | 11篇 |
1969年 | 15篇 |
1968年 | 13篇 |
1967年 | 12篇 |
排序方式: 共有1633条查询结果,搜索用时 15 毫秒
991.
Williams syndrome is a developmental disorder with a genetic basis, which results in an uneven cognitive profile with relatively strong language skills and severely impaired visuospatial abilities. To better understand the brain structure underlying this profile, we compared individuals with Williams syndrome with controls using multimodal neuroimaging data and new analytic methods (diffeomorphic mapping and atlas-based analysis). People with Williams syndrome had basal ganglia atrophy, while the fusiform, the medium temporal gyri, and the cerebellar cortex were relatively preserved. The right superior longitudinal fasciculus, the left frontooccipital fasciculus, the caudate, and the cingulum demonstrated increased fractional anisotropy, whereas the corticospinal tract revealed decreased values. These findings may be linked to the uneven cognitive profile evident in Williams syndrome. 相似文献
992.
We report the unusual case of a young child who developed an idiopathic basal cell carcinoma (BCC). The patient was otherwise healthy, with no history of excessive sun or radiation exposure or any predisposing factors for nonmelanoma skin cancer. This is a rare case that exemplifies the need for pediatricians and dermatologists to be aware that BCC may occur in children, even if they have no predisposing factors. 相似文献
993.
Kenney K Landau ME Gonzalez RS Hundertmark J O'Brien K Campbell WW 《Muscle & nerve》2012,45(3):356-362
Introduction: In this investigation we assessed the spectrum of creatine kinase (CK) responses in military recruits undergoing basic training. Methods: Musculoskeletal examination data, questionnaire findings, and CK levels were obtained from 499 recruits at days 0, 3, 7, and 14 of training. Correlations of CK with ethnicity, age, body mass index, exercise, muscle pain, and climate were obtained. Results: None of the subjects developed clinical exertional rhabdomyolysis (ER). The mean/median serum CK values were 223/157, 734/478, 1226/567, and 667/486 IU/L at days 0, 3, 7, and 14, respectively, with a wide overall range (34–35,056 IU/L). African‐American subjects had higher mean CK levels. Conclusions: CK elevations and muscle pain are common during basic training. Widely accepted laboratory diagnostic values for ER are routinely exceeded in this military recruits, suggesting that CK levels >50 times the upper limit of normal are more specific. The findings support using CK as a marker for ER. Normal laboratory reference ranges for CK should be published by ethnicity. Muscle Nerve, 2012 相似文献
994.
Landau YE Steinberg T Richmand B Leckman JF Apter A 《Journal of neural transmission (Vienna, Austria : 1996)》2012,119(5):621-626
Tourette’s syndrome is a neurodevelopmental disorder clinically characterized by multiple motor and phonic tics. It is likely
that a neurobiological susceptibility to the disorder is established during development by the interaction of genetic, biochemical,
immunological, and environmental factors. This study sought to investigate the possible correlation of several immunological
and biochemical markers with Tourette’s syndrome. Children with Tourette’s syndrome attending a tertiary pediatric medical
center from May 2008 to April 2010, and healthy age-matched control subjects underwent a comprehensive biochemical and immunological
work-up. Demographic data were abstracted from the medical records. Findings were compared between the groups and analyzed
statistically. Sixty-eight children with Tourette’s syndrome (58 males, 85.3%) and 36 healthy children (25 males, 69.4%) were
recruited. Compared with the control group, the Tourette’s syndrome group had significantly higher levels of ferritin (p = 0.01) and hemoglobin (p = 0.02), a lower level of zinc (p = 0.05), and a lower percentage of non-ceruloplasmin copper (p = 0.01). Analysis of the immunological markers revealed no significant between-group differences in IgA, IgM or IgG; however,
IgE and IgG-4 levels were significantly higher in the Tourette’s syndrome group (p = 0.04 and p = 0.02, respectively). Children with Tourette’s syndrome have high levels of biochemical indices of oxidative stress and
the quantitative immunoglobulins. These findings add to the still-limited knowledge on the pathogenesis of Tourette’s syndrome
and may have implications for the development of novel therapeutic modalities. 相似文献
995.
996.
Klostermann EC Braskie MN Landau SM O'Neil JP Jagust WJ 《Neurobiology of aging》2012,33(3):623-623.e24
Recent studies have linked dopamine to differences in behavior and brain activity in normal individuals. We explored these relationships in older and younger adults by investigating how functional connectivity between the striatum and prefrontal cortex is related to caudate dopamine and verbal working memory task performance. We studied 12 young and 18 older participants with functional magnetic resonance imaging (fMRI) during this task, and used positron emission tomography with the tracer 6-[18F]-fluoro-L-m-tyrosine (FMT) to assess dopamine synthesis capacity. Younger adults had a greater extent of frontal caudate functional connectivity during the load-dependent delay period of the working memory task than the older participants. Across all subjects, the extent of this functional connectivity was negatively correlated with dopamine synthesis capacity, such that participants with the greatest connectivity had the lowest caudate 6-[18F]-fluoro-L-m-tyrosine (FMT) signal. Additionally, the extent of functional connectivity was positively correlated with working memory performance. Overall these data suggest interdependencies exist between frontostriatal functional connectivity, dopamine, and working memory performance and that this system is functioning suboptimally in normal aging. 相似文献
997.
Retinal detachment results in visual loss and requires surgical treatment. The risk of retinal detachment depends, among other factors, on the vitreous rheology, which varies with age. To date, the viscoelasticity of the vitreous body has only been measured in cadaver eyes. However, the ex vivo and in vivo viscoelasticity may differ as a result of the effect of intravitreal membranes. Therefore, an MRI method and appropriate postprocessing tools were developed to determine the vitreous deformation and viscoelastic properties in the eyes of living humans. Nineteen subjects (eight women and 11 men; mean age, 33 years; age range, 14-62 years) gazed at a horizontal sinusoidal moving target during the segmented acquisition of complementary spatial modulation of magnetization images. The center of the lens and the scleral insertion of the optic nerve defined the imaging plane. The vitreous deformation was tracked with a dedicated algorithm and fitted with the commonly used viscoelastic model to determine the model parameters: the modified Womersley number a and the phase angle b. The vitreous deformation was successfully quantified in all 17 volunteers having a monophasic vitreous. The mean and standard deviation of the model parameters were determined to be 5.5 ± 1.3 for a and -2.3 ± 0.2 for b. The correlation coefficient (-0.76) between a and b was significant. At the eye movement frequency used, the mean storage and loss moduli of the vitreous were around 3 ± 1 hPa. For two subjects, the vitreous deformation was clearly polyphasic: some compartments of the vitreous were gel-like and others were liquefied. The borders of these compartments corresponded to reported intravitreal membrane patterns. Thus, the deformation of the vitreous can now be determined in situ, leaving the structure of the intravitreal membranes intact. Their effect on vitreous dynamics challenges actual vitreous viscoelastic models. The determination of the vitreous deformation will aid in the quantification of local vitreous stresses and their correlation with retinal detachment. 相似文献
998.
999.
1000.
S. Rushd A.B. Landau S.W. Lindow 《European journal of obstetrics, gynecology, and reproductive biology》2013