全文获取类型
收费全文 | 16898篇 |
免费 | 1480篇 |
国内免费 | 940篇 |
专业分类
耳鼻咽喉 | 153篇 |
儿科学 | 212篇 |
妇产科学 | 332篇 |
基础医学 | 2078篇 |
口腔科学 | 343篇 |
临床医学 | 2260篇 |
内科学 | 2668篇 |
皮肤病学 | 243篇 |
神经病学 | 876篇 |
特种医学 | 466篇 |
外国民族医学 | 7篇 |
外科学 | 1833篇 |
综合类 | 2445篇 |
现状与发展 | 1篇 |
一般理论 | 11篇 |
预防医学 | 953篇 |
眼科学 | 429篇 |
药学 | 1745篇 |
8篇 | |
中国医学 | 700篇 |
肿瘤学 | 1555篇 |
出版年
2024年 | 62篇 |
2023年 | 275篇 |
2022年 | 628篇 |
2021年 | 737篇 |
2020年 | 554篇 |
2019年 | 541篇 |
2018年 | 592篇 |
2017年 | 487篇 |
2016年 | 446篇 |
2015年 | 725篇 |
2014年 | 905篇 |
2013年 | 920篇 |
2012年 | 1317篇 |
2011年 | 1434篇 |
2010年 | 906篇 |
2009年 | 714篇 |
2008年 | 893篇 |
2007年 | 914篇 |
2006年 | 863篇 |
2005年 | 832篇 |
2004年 | 584篇 |
2003年 | 553篇 |
2002年 | 404篇 |
2001年 | 373篇 |
2000年 | 376篇 |
1999年 | 437篇 |
1998年 | 264篇 |
1997年 | 259篇 |
1996年 | 178篇 |
1995年 | 169篇 |
1994年 | 133篇 |
1993年 | 96篇 |
1992年 | 111篇 |
1991年 | 86篇 |
1990年 | 75篇 |
1989年 | 59篇 |
1988年 | 87篇 |
1987年 | 77篇 |
1986年 | 47篇 |
1985年 | 43篇 |
1984年 | 22篇 |
1983年 | 20篇 |
1982年 | 14篇 |
1981年 | 11篇 |
1980年 | 7篇 |
1979年 | 28篇 |
1978年 | 9篇 |
1975年 | 8篇 |
1974年 | 8篇 |
1972年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
To set up a method of amplification for the whole CagA gene of Helicobacter pylori and its fingerprinting by restriction fragment length polymorphism(RFLP),nested PCR was employed in combination with TD-PCR to amplify the gene and EcoRI and Hind Ⅲ were used to generate the RFLP fingerprinting.Target DNA fragments from 13 of 20 samples were successfully amplified and the relevant RFLP fingerprintings were obtained.It is concluded that the method can be used to amplify the whole CagA gene and CagA gene has apparent diversity of RFLP profile. 相似文献
52.
[目的]研究大豆蛋白对肾损害大鼠钙平衡的影响。[方法]选择3月龄断乳雄性SD大鼠40只.按体质量从小到大排序,采用完全随机化原则分为4组。每组10只。标准饲料对照组:喂食含有14%酪蛋白饲料;大豆蛋白饲料组:喂食含有14%大豆分离蛋白饲料;混合饲料1组:喂食含有7%酪蛋白加7%大豆分离蛋白饲料;混合饲料2组:喂食含有7%酪蛋白加14%大豆分离蛋白饲料。实验期用腺嘌呤灌胃共21d,建立肾损害大鼠模型,各组大鼠喂养相应饲料6周,测饲料消耗量、24h尿蛋白、尿钙、钙表观吸收率、储留钙量。[结果]4组实验大鼠饲料摄入量1d~30d无统计学差异,大豆蛋白饲料组和混合饲料1组实验结束时与另外两组相比,尿钙排泄量低,钙表观吸收率和储留钙量高,差异有统计学意义(P〈0.05)。[结论]蛋白质含量水平在14%条件下,含大豆蛋白的两种饲料对肾损害大鼠钙吸收、钙排泄的影响无统计学差异,有利于促进钙吸收,减少钙排泄。 相似文献
53.
54.
Locomotor strategies before independent walking: prospective study of 50 mentally retarded children.
To investigate the association between pre-walking locomotor strategies and psychomotor developments in children with mental retardation (MR), 50 children with non-specific MR were included in this study. There were 29 boys and 21 girls, 96% of whom had moderate to severe MR. They were followed from 4-53 months to 25-99 months of age, and their follow-up periods ranged from 10 to 48 months (mean 30 months). According to the pre-walking locomotor strategies, these children were categorized into three groups: the crawling group (n = 34) who used crawling or creeping as their main locomotion pattern before independent walking; the shuffling group (n = 9) who used shuffling prior to independent walking; and the direct-walking group (n = 7) who did not have any other locomotor strategies except rolling. In almost all motor developmental milestones, children in the direct-walking group developed earlier than those in the crawling and shuffling groups. Children in the crawling group had more advanced developments than those in the shuffling group. The difference in the mean ratio developmental quotients of the Bayley Mental Scale among the three groups was not significant. The present study showed that crawling may not be a necessary prerequisite for early ambulation or better cognitive function in MR children. 相似文献
55.
报告5例女性骨盆骨折合并阴道损伤,占骨盆骨折41例中的12.2%,均为交通事故伤,都合并有失血性休克,开放伤3例,闭合伤2例,治疗作阴道修补术2例,用碘仿纱条填塞阴道2例。未作处理1例,均治愈,阴道损伤表现为四型;横行撕裂伤,纵行撕裂伤,斜行撕裂伤和刺伤,强调早期诊断,及时治疗以防止合并症。 相似文献
56.
57.
344 cases of Heart-Qi Deficiency Syndrome (HQDS) including 19 Kinds of disease were observed to explore the rule of differentiation of symptoms and signs for HQDS. The results showed that the common symptoms of HQDS were weakness, shortness of breath, and palpitation, etc. According to with or without complicated cardiovascular diseases, the patients were divided into two groups: group A with cardiovascular diseases, group B without that. In group A, the symptoms and signs of HQDS were the most frequent and early clinical manifestations, the associated symptoms and signs were blood stasis and attack of water-evil, etc. In group B, in whom often associated with nervous and emotional symptoms such as insomnia, dreamfulness, and amnesia, etc., which was due to the disturbance of emotional activities of heart. In order to avoid diagnostic confusion, the authors suggest that the HQDS patients with cardiovascular diseases would be diagnosed as HQDS; on the other hand, the HQDS patients without cardiovascular diseases would be diagnosed as disturbance of emotional activities of heart. 相似文献
58.
Summary From 1987 to 1990 the authors treated 20 cases of spondylolisthesis by an improved operative procedure including excision
of the medial part of the superior articular processes of the slipped vertebra, excision of the soft tissue between the ununited
isthmi, and excision of the ligamentum flavum between the intervertebral space above the slipped segment. In some instances
the lower portion of the lamina over the slipped vertebra should be resected. A U-shaped rod was used to hold sublaminar fixation
of two segments above and below the slipped vertebra, with the slipped vertebra spared. Utilizing the U-shaped rod as support,
bone strips were placed along the lateral and anterior sides of the rod to bridge the gap between the laminae of the displaced
vertebra. Other bone grafts were focused on the facet joints. The patients were allowed ambulation early postoperatively.
19 cases could be evaluated at preliminary follow-up. All showed satisfactory results. 相似文献
59.
Xuyu Zu Ruilan Yan Sarah Robbins Paulette A Krishack Duan-Fang Liao Deliang Cao 《Toxicological sciences》2007,97(2):562-568
Acrolein is a highly reactive alpha,beta-unsaturated aldehyde produced endogenously during lipid peroxidation and naturally distributed pervasively in living environments, posing serious threats to human health if not properly metabolized. In this study, we report aldose reductase-like-1 (ARL-1) as a novel enzyme that catalyzes the reduction of acrolein and protects cells from their toxicity. Using purified ARL-1 protein, we determined its enzymatic activity in response to acrolein and defined its steady-state kinetics with K(m) and V(max) at 0.110 +/- 0.012 mM and 3122.0 +/- 64.7 nmol/mg protein/min, respectively. By introducing a functional Enhanced Green Fluorescent Protein (EGFP)/ARL-1 fusion protein into 293T cells, we demonstrated that plating efficiency in liquid culture and focus formation in soft agar increased by more than 60% (p < 0.05), compared to the vector control cells. More significantly, at a low dose of 5 microM acrolein, EGFP/ARL-1 expression enhanced both plating efficiency and focus formation by more than threefold, and the foci (in soft agar) of 293T cells expressing EGFP/ARL-1 were significantly larger than those of the vector control cells. At high concentrations of acrolein (25 and 50 microM), EGFP/ARL-1 protein prevented oncotic death of 293T cells induced by acrolein. In summary, our data demonstrated for the first time that the ARL-1 protein protects 293T cells from acrolein toxicity. Due to the high toxicity and wide distribution of acrolein, this finding is important to the understanding of its detoxification mechanisms. 相似文献
60.
胃癌双对比造影表现与血5‘—核苷酸酶相关性的研究 总被引:1,自引:0,他引:1
目的 初步探讨胃癌影像学表现与 5′-核苷酸酶 (5′- NT)活性的变化关系。方法 经病理证实的 4 1例胃癌 ,均行 X线双对比造影摄片 ,并采用分光光度法测其治疗前血清 5′- NT活性。以 4 0例健康人作对照组。结果 胃癌组 5′- NT活性 (1.14± 0 .16 u/ ml)较正常健康人明显减低 (2 .6 0± 0 .10 u/ m l) (P<0 .0 5 )。解剖部位上 ,从贲门、胃体到胃窦部胃癌 ,其 5′- NT活性分别为 0 .98、1.2 0、1.2 8u/ m l,呈逐渐升高的趋势。溃疡型胃癌 5′- NT活性(0 .96 u/ ml)低于肿块型 (1.12 u/ m l)和浸润型 (1.4 0 u/ ml)。 期胃癌 5′- NT(1.5 3u/ ml)高于 期 (0 .83u/ m l)、 期 (0 .98u/ ml)和 期 (1.0 3u/ m l) (P<0 .0 5 )。结论 胃癌患者血清 5′- NT活性明显较正常人降低 ,其酶活性的变化与胃癌的形态、生长部位及进展程度有一定的相关 相似文献