全文获取类型
收费全文 | 14271篇 |
免费 | 1349篇 |
国内免费 | 609篇 |
专业分类
耳鼻咽喉 | 131篇 |
儿科学 | 155篇 |
妇产科学 | 195篇 |
基础医学 | 1639篇 |
口腔科学 | 371篇 |
临床医学 | 1290篇 |
内科学 | 1621篇 |
皮肤病学 | 135篇 |
神经病学 | 1353篇 |
特种医学 | 394篇 |
外科学 | 1154篇 |
综合类 | 2125篇 |
现状与发展 | 2篇 |
一般理论 | 1篇 |
预防医学 | 2595篇 |
眼科学 | 291篇 |
药学 | 1713篇 |
3篇 | |
中国医学 | 343篇 |
肿瘤学 | 718篇 |
出版年
2024年 | 17篇 |
2023年 | 209篇 |
2022年 | 241篇 |
2021年 | 525篇 |
2020年 | 499篇 |
2019年 | 541篇 |
2018年 | 515篇 |
2017年 | 583篇 |
2016年 | 605篇 |
2015年 | 587篇 |
2014年 | 858篇 |
2013年 | 1310篇 |
2012年 | 768篇 |
2011年 | 976篇 |
2010年 | 711篇 |
2009年 | 726篇 |
2008年 | 755篇 |
2007年 | 716篇 |
2006年 | 625篇 |
2005年 | 564篇 |
2004年 | 475篇 |
2003年 | 453篇 |
2002年 | 365篇 |
2001年 | 343篇 |
2000年 | 265篇 |
1999年 | 218篇 |
1998年 | 216篇 |
1997年 | 178篇 |
1996年 | 102篇 |
1995年 | 133篇 |
1994年 | 121篇 |
1993年 | 123篇 |
1992年 | 120篇 |
1991年 | 115篇 |
1990年 | 109篇 |
1989年 | 103篇 |
1988年 | 85篇 |
1987年 | 70篇 |
1986年 | 54篇 |
1985年 | 43篇 |
1984年 | 43篇 |
1983年 | 31篇 |
1982年 | 24篇 |
1981年 | 25篇 |
1980年 | 22篇 |
1979年 | 12篇 |
1978年 | 17篇 |
1977年 | 11篇 |
1976年 | 7篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
《Diagnostic Histopathology》2022,28(11):493-500
After decades of relative stagnation lung cancer is emerging as a disease type where rapid progress is being made in diagnosis and therapy, as well as in our understanding of disease biology. Much of this progress is of immediate impact to diagnosticians, and more is likely to affect diagnostic practice in the near future. In this review we seek to briefly summarize several key areas of active research of immediate or probable imminent value to trainee and consultant pulmonary pathologists alike. We cover some major changes in tumour classification, grading, and patient stratification, as well as considering the state of the art in machine-assisted interpretation of lung cancer histology, and the use of genetically modified lung cancer models. 相似文献
4.
Unconditional Positivity-Preserving and Energy Stable Schemes for a Reduced Poisson-Nernst-Planck System 下载免费PDF全文
Hailiang Liu & Wumaier Maimaitiyiming 《Communications In Computational Physics》2020,27(5):1505-1529
The Poisson-Nernst-Planck (PNP) system is a widely accepted model for
simulation of ionic channels. In this paper, we design, analyze, and numerically validate a second order unconditional positivity-preserving scheme for solving a reduced
PNP system, which can well approximate the three dimensional ion channel problem.
Positivity of numerical solutions is proven to hold true independent of the size of time
steps and the choice of the Poisson solver. The scheme is easy to implement without
resorting to any iteration method. Several numerical examples further confirm the
positivity-preserving property, and demonstrate the accuracy, efficiency, and robustness of the proposed scheme, as well as the fast approach to steady states. 相似文献
5.
《Brain stimulation》2020,13(1):175-189
BackgroundTranscranial magnetic stimulation (TMS) enables non-invasive modulation of brain activity with both clinical and research applications, but fundamental questions remain about the neural types and elements TMS activates and how stimulation parameters affect the neural response.ObjectiveTo develop a multi-scale computational model to quantify the effect of TMS parameters on the direct response of individual neurons.MethodsWe integrated morphologically-realistic neuronal models with TMS-induced electric fields computed in a finite element model of a human head to quantify the cortical response to TMS with several combinations of pulse waveforms and current directions.ResultsTMS activated with lowest intensity intracortical axonal terminations in the superficial gyral crown and lip regions. Layer 5 pyramidal cells had the lowest thresholds, but layer 2/3 pyramidal cells and inhibitory basket cells were also activated at most intensities. Direct activation of layers 1 and 6 was unlikely. Neural activation was largely driven by the field magnitude, rather than the field component normal to the cortical surface. Varying the induced current direction caused a waveform-dependent shift in the activation site and provided a potential mechanism for experimentally observed differences in thresholds and latencies of muscle responses.ConclusionsThis biophysically-based simulation provides a novel method to elucidate mechanisms and inform parameter selection of TMS and other cortical stimulation modalities. It also serves as a foundation for more detailed network models of the response to TMS, which may include endogenous activity, synaptic connectivity, inputs from intrinsic and extrinsic axonal projections, and corticofugal axons in white matter. 相似文献
6.
Harit Kapoor Kush Raj Lohani Tommy H. Lee Devendra K. Agrawal Sumeet K. Mittal 《CTS Clinical and Translational Science》2015,8(6):841-847
Esophageal adenocarcinoma is the fastest rising cancer in the United States. It develops from long‐standing gastroesophageal reflux disease which affects >20% of the general population. It carries a very poor prognosis with 5‐year survival <20%. The disease is known to sequentially progress from reflux esophagitis to a metaplastic precursor, Barrett''s esophagus and then onto dysplasia and esophageal adenocarcinoma. However, only few patients with reflux develop Barrett''s esophagus and only a minority of these turn malignant. The reason for this heterogeneity in clinical progression is unknown. To improve patient management, molecular changes which facilitate disease progression must be identified. Animal models can provide a comprehensive functional and anatomic platform for such a study. Rats and mice have been the most widely studied but disease homology with humans has been questioned. No animal model naturally simulates the inflammation to adenocarcinoma progression as in humans, with all models requiring surgical bypass or destruction of existing antireflux mechanisms. Valuable properties of individual models could be utilized to holistically evaluate disease progression. In this review paper, we critically examined the current animal models of Barrett''s esophagus, their differences and homologies with human disease and how they have shaped our current understanding of Barrett''s carcinogenesis. 相似文献
7.
目的:探讨三种不同引流方式对食管癌术后颈部吻合口瘘的引流效果。方法:收集从2013年1月到2016年9月在我科行食管癌手术并术后发生颈部吻合口瘘患者,比较入组患者所采用的不同颈部引流方式的优劣。结果:共有83例患者纳入研究,有34例进入A组,行纱布条引流组;28例进入B组,行造瘘袋引流组;21例进入C组,行胃管负压引流组。所有入组患者一般资料和手术资料对比无明显统计学差异(P>0.05)。观察指标对比结果显示,C组患者瘘口愈合时间较其他两组时间短[(15.90±4.18)天vs(14.60±4.41)天vs(9.65±3.80)天],住院时间较其他两组短[(18.10±4.17)天vs(16.20±3.78)天vs(12.30±3.29)天],换药次数较其他两组少[(37.55±8.75)天vs(14.5±3.23)天vs(10.00±2.05)天],抗生素使用时间也较其他组明显减少[(13.10±2.49)天vs(10.85±1.84)天vs(7.20±1.74)天]。结论:颈部放置负压引流有助于食管癌术后颈部吻合口瘘愈合,值得临床推广与进一步研究。 相似文献
8.
An-feng TAO Zheng-hao XU Cheng-hao WU Yi WANG Wei-wei HOU Shi-hong ZHANG Zhong CHEN 《浙江大学学报(医学版)》2015,44(3):315
目的观察比较不同脉冲波形的低频率电刺激对海马电点燃癫痫模型小鼠的作用差异。方法采用电点燃刺激法建立小鼠癫痫模型, 观察正弦波、单相方波、双相方波低频率电刺激对模型小鼠癫痫行为发作及后放电持续时间的影响, 并比较不同时间点给予正弦波低频率电刺激的抗癫痫作用。结果与对照组比较, 正弦波低频率电刺激30 s能降低小鼠海马电点燃癫痫发作等级(2.85 ± 0.27 vs 4.75 ±0.12, P < 0.05)、减少大发作概率(53.6% vs 96.5%, P < 0.01) 和缩短后放电持续时间[(16.22 ± 1.69) s vs (30.29 ± 1.12) s, P < 0.01], 而单相方波和双相方波低频率电刺激30 s没有明显的抗癫痫作用。常用的单相方波低频率电刺激15 min能降低小鼠海马电点燃发作等级(3.58 ± 0.16, P < 0.05)、减少大发作概率(66.7%, P < 0.01);但对海马后放电持续时间及大发作持续时间无影响(均 P>0.05)。此外, 电点燃刺激前预先给予或结束后3 s内给予正弦波低频率电刺激具有明显的抗癫痫作用( P < 0.05或 P < 0.01), 而电点燃刺激结束10 s给予正弦波低频率电刺激则无上述抗癫痫作用。 结论低频率电刺激抗癫痫作用受波形参数的影响, 其中正弦波低频率电刺激能有效抑制小鼠海马电点燃癫痫的发作。 相似文献
9.
10.
Marie V. Plaisime PhD MPH Marie Jipguep-Akhtar PhD Joseph J. Locascio PhD Harolyn M. E. Belcher MD MHS Rachel R. Hardeman PhD MPH Katherine Picho-Kiroga PhD Sylvia P. Perry PhD Sean M. Phelan PhD MPH Michelle van Ryn PhD LMFT MPH John F. Dovidio PhD 《Health services research》2023,58(Z2):229-237