全文获取类型
收费全文 | 5561篇 |
免费 | 409篇 |
国内免费 | 244篇 |
专业分类
耳鼻咽喉 | 33篇 |
儿科学 | 57篇 |
妇产科学 | 72篇 |
基础医学 | 880篇 |
口腔科学 | 170篇 |
临床医学 | 847篇 |
内科学 | 585篇 |
皮肤病学 | 46篇 |
神经病学 | 431篇 |
特种医学 | 338篇 |
外科学 | 460篇 |
综合类 | 368篇 |
现状与发展 | 1篇 |
预防医学 | 535篇 |
眼科学 | 65篇 |
药学 | 594篇 |
3篇 | |
中国医学 | 371篇 |
肿瘤学 | 358篇 |
出版年
2024年 | 14篇 |
2023年 | 380篇 |
2022年 | 582篇 |
2021年 | 625篇 |
2020年 | 535篇 |
2019年 | 346篇 |
2018年 | 275篇 |
2017年 | 254篇 |
2016年 | 229篇 |
2015年 | 286篇 |
2014年 | 407篇 |
2013年 | 282篇 |
2012年 | 288篇 |
2011年 | 317篇 |
2010年 | 292篇 |
2009年 | 234篇 |
2008年 | 92篇 |
2007年 | 133篇 |
2006年 | 107篇 |
2005年 | 70篇 |
2004年 | 64篇 |
2003年 | 66篇 |
2002年 | 89篇 |
2001年 | 79篇 |
2000年 | 50篇 |
1999年 | 72篇 |
1998年 | 45篇 |
1989年 | 1篇 |
排序方式: 共有6214条查询结果,搜索用时 15 毫秒
1.
2.
3.
Obsessive-compulsive disorder (OCD) is a type of hereditary mental illness, which seriously affect the normal life of the patients. Sparse learning has been widely used in detecting brain diseases objectively by removing redundant information and retaining monitor valuable biological characteristics from the brain functional connectivity network (BFCN). However, most existing methods ignore the relationship between brain regions in each subject. To solve this problem, this paper proposes a spatial similarity-aware learning (SSL) model to build BFCNs. Specifically, we embrace the spatial relationship between adjacent or bilaterally symmetric brain regions via a smoothing regularization term in the model. We develop a novel fused deep polynomial network (FDPN) model to further learn the powerful information and attempt to solve the problem of curse of dimensionality using BFCN features. In the FDPN model, we stack a multi-layer deep polynomial network (DPN) and integrate the features from multiple output layers via the weighting mechanism. In this way, the FDPN method not only can identify the high-level informative features of BFCN but also can solve the problem of curse of dimensionality. A novel framework is proposed to detect OCD and unaffected first-degree relatives (UFDRs), which combines deep learning and traditional machine learning methods. We validate our algorithm in the resting-state functional magnetic resonance imaging (rs-fMRI) dataset collected by the local hospital and achieve promising performance. 相似文献
4.
《Digestive and liver disease》2022,54(11):1486-1493
BackgroundCold snare polypectomy (CSP) is a promising technique for the removal of sessile serrated polyps (SSPs) ≥ 10 mm. However, the efficacy and safety of this technique remain undetermined.AimsWe aimed to comprehensively evaluate the efficacy and safety of CSP for SSPs ≥ 10 mm.MethodsPubMed, EMBASE, Web of Science and Cochrane Library were searched up to January 2021.ResultsA total of 10 studies consisting of 1727 SSPs (range, 10–40 mm) from 1021 patients were included. The overall rates of technical success, adverse events (AEs) and residual SSPs were 100%, 0.7% and 2.9%, respectively. Subgroup analysis showed that the rates of technical success and AEs were comparable between CSP and cold endoscopic mucosal resection (EMR) (99.9% vs. 100% and 1.3% vs. 0.5%, respectively), between the proximal and distal colon (100% vs. 99.9% and 0.3% vs. 0, respectively), and between polyps of 10–19 mm and ≥20 mm (99.8% vs. 100% and 0.9% vs. 0, respectively). However, subgroup analysis showed that the rate of residual SSPs was slightly lower in CSP compared with cold EMR (1.3% vs. 3.9%), as well as in polyps of 10–19 mm compared with those ≥20 mm (3.1% vs. 4.7%).ConclusionCSP was an effective and safe technique for removing SSPs ≥ 10 mm. 相似文献
5.
6.
7.
《Journal of pharmaceutical sciences》2023,112(4):1052-1063
Most food, pharmaceutical, and chemical industries rely heavily on the supply of free-flowing powders that finds their application in raw materials, additives, and manufactured products. Improper storage conditions combined with environmental factors affect the free-flowing ability of powders. An undesirable transformation of these free-flowing powders into a coherent mass that resists flow is called caking. An important metric that can be used to measure the caking propensity of a material is the tensile strength, which is essentially the resistant stress needed to separate two layers of materials using an isostatic tensile strain. Even though several models have quantified the propensity of caking, the complex nature of interactions between the powder and its micro-environment makes the prediction of caking a challenging task. In the present work, the onset of tensile strength in isomalt with changes in temperature, relative humidity, and consolidation pressures using a shear cell was modeled using a finite element approach. The study found that at a consolidation pressure of 3 kPa and relative humidity of 85±0.1%, an increase in temperature by 5˚C increased the tensile strength of isomalt by a factor of 2. On the other hand, at a constant temperature of 25˚C, an increase in relative humidity from 85±0.1% to 86±0.1% registered an increase in tensile strength by 42.7%. This study also found that an increase in consolidation pressure from 3 kPa to 6 and 9 kPa increased the tensile strength by a factor of 1.79 and 2.54, respectively. The model had good agreement with the measurements and had an overall MAPE of 12.13%. This model can be applied to study the influence of extrinsic parameters on the propensity of caking during storage of bulk solids. 相似文献
8.
《Gait & posture》2022
BackgroundIt is unknown if improvements in gait velocity following an aerobic cycling intervention are accompanied by improved gait biomechanics in individuals with Parkinson’s disease (PD) or if gait abnormalities are exaggerated in response to increased velocity.Research questionCan an 8-week aerobic cycling intervention elicit improvements in locomotor function in individuals with mild to moderate PD?MethodsA secondary analysis of data from a randomized clinical trial was conducted in individuals with mild to moderate idiopathic PD (N = 28). Participants were randomized to an aerobic cycling intervention (PDex, N = 14) consisting of 24 sessions at a targeted aerobic intensity of 60–80% of heart rate reserve or to a no intervention control group (PDcontrol, N = 14). Change in comfortable walking speed in addition to gait kinematics, kinetics, and spatiotemporal variables using motion capture were obtained at baseline and end of treatment (EOT).ResultsThe PDex group made significantly greater improvements in the primary outcome, change in comfortable gait velocity, from 0.86 ± 0.24 m/s at baseline to 1.00 ± 0.23 m/s at EOT compared to the PDcontrol group who declined from 0.91 ± 0.23 m/s at baseline to 0.80 ± 0.29 at EOT (P = 0.002). Improvements in gait velocity for the PDex group were accompanied by improvements in gait kinematics, kinetics, and spatiotemporal parameters, while the PDcontrol group demonstrated slight worsening in all gait parameters over the 8-week period.SignificanceThe 8-week moderate- to high-intensity cycling intervention elicited significantly greater improvements in gait velocity compared to the PDcontrol group. Increased gait velocity was accompanied by normalization of gait biomechanics, rather than an exaggeration of existing gait deviations. Aerobic cycling may be a viable treatment approach to improve gait velocity and gait biomechanics in individuals with mild to moderate PD and may mitigate declines in mobility. 相似文献
9.
10.