全文获取类型
收费全文 | 39666篇 |
免费 | 3996篇 |
国内免费 | 1598篇 |
专业分类
耳鼻咽喉 | 402篇 |
儿科学 | 754篇 |
妇产科学 | 628篇 |
基础医学 | 3797篇 |
口腔科学 | 808篇 |
临床医学 | 4903篇 |
内科学 | 5978篇 |
皮肤病学 | 606篇 |
神经病学 | 2291篇 |
特种医学 | 1302篇 |
外国民族医学 | 2篇 |
外科学 | 3724篇 |
综合类 | 5846篇 |
现状与发展 | 17篇 |
一般理论 | 25篇 |
预防医学 | 4017篇 |
眼科学 | 1005篇 |
药学 | 4201篇 |
56篇 | |
中国医学 | 2465篇 |
肿瘤学 | 2433篇 |
出版年
2024年 | 171篇 |
2023年 | 535篇 |
2022年 | 1435篇 |
2021年 | 1877篇 |
2020年 | 1529篇 |
2019年 | 1219篇 |
2018年 | 1402篇 |
2017年 | 1354篇 |
2016年 | 1209篇 |
2015年 | 1668篇 |
2014年 | 1998篇 |
2013年 | 2214篇 |
2012年 | 3295篇 |
2011年 | 3372篇 |
2010年 | 2424篇 |
2009年 | 2058篇 |
2008年 | 2577篇 |
2007年 | 2386篇 |
2006年 | 2135篇 |
2005年 | 1936篇 |
2004年 | 1437篇 |
2003年 | 1332篇 |
2002年 | 1097篇 |
2001年 | 477篇 |
2000年 | 410篇 |
1999年 | 288篇 |
1998年 | 297篇 |
1997年 | 232篇 |
1996年 | 186篇 |
1995年 | 169篇 |
1994年 | 164篇 |
1993年 | 124篇 |
1992年 | 180篇 |
1991年 | 193篇 |
1990年 | 158篇 |
1989年 | 137篇 |
1988年 | 126篇 |
1987年 | 127篇 |
1986年 | 137篇 |
1985年 | 126篇 |
1984年 | 120篇 |
1983年 | 106篇 |
1982年 | 96篇 |
1981年 | 68篇 |
1980年 | 69篇 |
1979年 | 72篇 |
1978年 | 72篇 |
1977年 | 61篇 |
1976年 | 34篇 |
1974年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Jessica Lasky-Su Tobias Banaschewski Jan Buitelaar Barbara Franke Keeley Brookes Edmund Sonuga-Barke Richard Ebstein Jacques Eisenberg Michael Gill Iris Manor Ana Miranda Fernando Mulas Robert D Oades Herbert Roeyers Aribert Rothenberger Joseph Sergeant Hans-Christoph Steinhausen Eric Taylor Kaixin Zhou Margaret Thompson Philip Asherson Stephen V Faraone 《Neuropsychopharmacology》2007,62(9):985-990
BACKGROUND: Previous research found an association between single nucleotide polymorphisms (SNPs) in the promoter region of DRD4 and statistically derived phenotypes generated from attention-deficit/hyperactivity disorder (ADHD) symptoms. We sought to replicate this finding by using the same methodology in an independent sample of ADHD individuals. METHODS: Four SNPs were genotyped in and around DRD4 in 2631 individuals in 642 families. We developed a quantitative phenotype at each SNP by weighting nine inattentive and nine hyperactive-impulsive symptoms. The weights were selected to maximize the heritability at each SNP. Once a quantitative phenotype was generated at each SNP, the screening procedure implemented in PBAT was used to select and test the five SNPs/genetic model combinations with the greatest power to detect an association for DRD4. RESULTS: One of the four SNPs was associated with the quantitative phenotypes generated from the ADHD symptoms (corrected p-values = .02). A rank ordering of the correlation between each of the ADHD symptoms and the quantitative phenotype suggested that hyperactive-impulsive symptoms were more strongly correlated with the phenotype; however, including inattentive symptoms was necessary to achieve a significant result. CONCLUSIONS: This study partially replicated a previous finding by identifying an association between rs7124601 and a quantitative trait generated from ADHD symptoms. The rs7124601 is in linkage disequilibrium (LD) with the SNPs identified previously. In contrast to the previous study, this finding suggests that both hyperactive-impulsive and inattentive symptoms are important in the association. 相似文献
53.
54.
目的 观察营养素食预防化疗患者便秘的效果。方法 选择128例化疗患者,随机分为观察组和对照组各61例,对照组常规正常饮食,观察组于化疗开始当天实施营养素食.连续7~10d,比较两组患者便秘发生率及体重、血红蛋白、白蛋白等指标。结果 对照组便秘发生率显著高于观察组(P〈0.01);两组化疗后营养指标比较,差异无显著性意义(均P〉0.05)。结论 营养素食对化疗患者便秘有较好的预防作用。 相似文献
55.
Matthias Peltz Tian-Teng He Glenn A Adams Robert Y Chao Michael E Jessen Dan M Meyer 《The Journal of heart and lung transplantation》2005,24(7):896-903
BACKGROUND: Lungs harvested for transplantation are stored while inflated with oxygen, which can serve to support oxidative metabolism. However, strategies aimed at increasing graft metabolism during storage have received little attention. In this study, we added pyruvate to the preservation solution Perfadex and measured the effects on oxidative metabolism and reperfusion lung function. METHODS: Rat lungs were stored for 6 and 24 hours in low-potassium dextran solution at 10 degrees C containing either 5 mmol/liter uniformly carbon-13 (U-(13)C) labeled glucose (Perfadex), 32 mmol/liter 3-(13)C pyruvate (pyruvate), or both (combined). Oxidation of exogenous substrates was measured as the incorporation of (13)C into tricarboxylic acid cycle intermediates by magnetic resonance spectroscopy. Additional groups of lungs with each substrate modification were preserved for 6 or 24 hours and then reperfused. RESULTS: Enrichment of tricarboxylic acid cycle intermediates was low in the Perfadex group (9% at 6 hours and 32% at 24 hours of storage, respectively). In contrast, enrichment was significantly increased in both the pyruvate group (50% and 59%, respectively) and combined group (39% and 54%, respectively) compared with the Perfadex group (p<0.01). Graft function was excellent after 6-hour storage in all groups. All lungs stored for 24 hours exhibited inferior lung function, but oxygenation, pulmonary artery pressures, and airway pressures in the combined group were significantly improved compared with the Perfadex group (p<0.05). CONCLUSIONS: Preservation solution substrate composition influences graft metabolism during storage. The addition of pyruvate to Perfadex increases metabolism during storage and improves reperfusion lung function. 相似文献
56.
本实验复制24只杂种犬心肌缺血再灌注损伤病理模型,应用与生理盐水、丹参对比的方法观察通脉灵对血液动力学及心功能的影响。结果表明,通脉灵小剂量组(TM1G)、通脉灵大剂量组(TM2G)和丹参对照组(DSG)的心输出量(CO),心脏指数(CI),心搏指数(SI)、左室内压峰值(LVSP)及左室内压最大变化速率(±dp/dtmsx)均明显高于生理盐水对照组(NSG)。本实验证明,通脉灵主要是通过保护心肌舒缩功能改善血液动力学指标进而防止缺血再灌注时心功能不全的发生。 相似文献
57.
58.
59.
60.
LUO Dan 《中华医学杂志(英文版)》2003,116(8):1277-1277