全文获取类型
收费全文 | 36580篇 |
免费 | 3717篇 |
国内免费 | 1591篇 |
专业分类
耳鼻咽喉 | 354篇 |
儿科学 | 669篇 |
妇产科学 | 551篇 |
基础医学 | 3462篇 |
口腔科学 | 710篇 |
临床医学 | 4503篇 |
内科学 | 5240篇 |
皮肤病学 | 569篇 |
神经病学 | 2080篇 |
特种医学 | 1047篇 |
外国民族医学 | 2篇 |
外科学 | 3385篇 |
综合类 | 5725篇 |
现状与发展 | 17篇 |
一般理论 | 25篇 |
预防医学 | 3670篇 |
眼科学 | 996篇 |
药学 | 4102篇 |
55篇 | |
中国医学 | 2446篇 |
肿瘤学 | 2280篇 |
出版年
2024年 | 169篇 |
2023年 | 521篇 |
2022年 | 1419篇 |
2021年 | 1834篇 |
2020年 | 1500篇 |
2019年 | 1181篇 |
2018年 | 1340篇 |
2017年 | 1328篇 |
2016年 | 1184篇 |
2015年 | 1610篇 |
2014年 | 1924篇 |
2013年 | 2095篇 |
2012年 | 3131篇 |
2011年 | 3205篇 |
2010年 | 2323篇 |
2009年 | 1979篇 |
2008年 | 2457篇 |
2007年 | 2269篇 |
2006年 | 2023篇 |
2005年 | 1832篇 |
2004年 | 1349篇 |
2003年 | 1249篇 |
2002年 | 1018篇 |
2001年 | 392篇 |
2000年 | 340篇 |
1999年 | 228篇 |
1998年 | 253篇 |
1997年 | 189篇 |
1996年 | 137篇 |
1995年 | 124篇 |
1994年 | 127篇 |
1993年 | 86篇 |
1992年 | 99篇 |
1991年 | 99篇 |
1990年 | 79篇 |
1989年 | 57篇 |
1988年 | 52篇 |
1987年 | 48篇 |
1986年 | 61篇 |
1985年 | 51篇 |
1984年 | 58篇 |
1983年 | 60篇 |
1982年 | 69篇 |
1981年 | 46篇 |
1980年 | 38篇 |
1979年 | 23篇 |
1978年 | 32篇 |
1977年 | 31篇 |
1974年 | 18篇 |
1973年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
目的研究肥厚梗阻型心肌病患者经皮腔内室间隔心肌消融术对心电指标的影响。方法对50例肥厚梗阻型心肌病患者行经皮腔内室间隔心肌消融术,记录术前、术中和术后出现的心律失常类型,配对分析术前、术后心电指标的变化。结果术后与术前相比,QRS时限[(122.0±24.0)ms对(97.3±15.5)ms,P=0.000]明显延长,QTc[(469.3±32.2)ms对(434.3±41.5)ms,P=0.004]、PR间期[(169±26)ms对(162±24)ms,P=0.044]稍延长。术中心律失常发生率分别为:右束支传导阻滞70%(35/50),左束支传导阻滞8%(4/50),一过性AVB38%(19/50),频发室性早搏24%(12/50),短阵室性心动过速24%(12/50);未发生持续性室性心动过速和室颤。术后心律失常发生率分别为:右束支传导阻滞56%(28/50),左束支传导阻滞8%(4/50),交界区性心动过速4%(2/50),频发室性早搏16%(8/50),短阵室性心动过速8%(4/50)。无永久性起搏器植入及死亡病例。结论经皮腔内室间隔心肌消融术致心律失常的发生率高,右束支传导阻滞最为常见。严格选择适应证后谨慎地行PTSMA术是安全、可行的。 相似文献
102.
103.
目的从基因水平调查了中国华南、华北地区人群HLA-DQB1等位基因频率,并研究比较两地区人群HLA-DQB1多态性分布。方法采用深圳益生堂生物企业有限公司研制开发的“HLA-DQB1低分辨率分型基因芯片检测试剂盒”,应用聚合酶链反应.序列特异性引物+序列特异性寡核苷酸探针芯片检测技术,对700名南方地区的中国人和320名北方地区的中国人进行基因分型。结果鉴定了10个HLA-DQB1等位基因,获得了一组准确、科学的统计数据。结论得到了中国华南、华北地区人群HLA-DQB1等位基因频率差异的数据,证明中国人群HLA-DQB1*02,05,0601,0602,0603的分布南北差异有统计学意义(P〈0.05),为疾病相关性研究、人文科学研究提供了可靠的遗传学数据。 相似文献
104.
本文报告了急性脑血管病的脑电地形图与脑CT的对比研究。介绍了急性脑血管病的脑电地形图改变,对脑电地形图与脑CT在急性脑血管病诊断上的优劣进行了对比,进一步讨论了脑电地形图在急性脑血管病中的临床应用价值。 相似文献
105.
M Andries Monyeki Lando L J Koppes K Dan Monyeki Han C G Kemper Jos W R Twisk 《American journal of human biology》2007,19(4):551-558
The objective of this study was to investigate the development and tracking of nutritional status, body composition and physical fitness, and the longitudinal relationship of changes in nutritional status, and body composition with changes in physical fitness over a 1-year period of follow-up. Studied were 380 boys and 322 girls aged 7-14 years from the Ellisras Longitudinal Study. Boys and girls were divided into two groups of pre-adolescence (<11 years) and adolescence (>10 years). High tracking coefficients (>8) were found for nutritional status, body mass index, and fat-free mass, while low tracking coefficients (<4) were found for the sum of skinfolds, fat mass, arm muscle area, and central fat distribution. Moderate and low tracking coefficients were found for the physical fitness items. Longitudinal regression analyses showed that physical fitness performances that require a high energy flux over a short period of time are affected by muscle wasting, whereas having a low body weight appears to be important for a good performance on other fitness items in these malnourished rural South African children. 相似文献
106.
107.
1 Introduction
Clinical trials have demonstrated that ex vivo expanded hematopoietic stem cells (HSCs) and progenitors offer great promise in reconstituting in vivo hematopoiesis in patients who have undergone intensive chemotherapy.It is therefore necessary to develop a clinical-scale culture system to provide the expanded HSCs and progenitors.Static culture systems such as T-flasks and gas-permeable blood bags are the most widely used culture devices for expanding hematopoietic cells. But they reveal several inherent limitations: ineffective mixing, lack of control options for dissolved oxygen and pH and difficulty in continuous feeding, which restricts the usefulness of static systems. Several advanced bioreactors have been used in the field of HSCs expansion. But hematopoietic cells are extremely sensitive to shear, so cells in bioreactors such as stirred and perfusion culture systems may suffer physical damage. This problem will be improved by applying the rotating wall vessel (RWV) bioreactor in clinic because of its low shear and unique structure. In this research, cord blood (CB) HSCs were expanded by means of a cell-dilution feeding protocol in RWV. 相似文献
108.
Establishment and Functional Implications of B-cell Connectivity 总被引:7,自引:0,他引:7
109.
Lung preservation solution substrate composition affects rat lung oxidative metabolism during hypothermic storage 总被引:1,自引:0,他引:1
Peltz M Hamilton TT He TT Adams GA Koshy S Burgess SC Chao RY Jessen ME Meyer DM 《Respiratory physiology & neurobiology》2005,148(3):2771-283
Lungs harvested for transplantation utilize oxygen after procurement. We investigated the effects of storage solution substrate composition on pulmonary oxidative metabolism and energetics during the preservation interval. Rat lungs were harvested and stored at 10 degrees C in low-potassium dextran (LPD) solution. Groups of lungs were preserved with preservation solution containing 5mM carbon-13 ((13)C) labeled glucose or increasing concentrations of (13)C labeled pyruvate. Additional groups of rat lungs were studied with dichloroacetate (DCA) added to the pyruvate-modified preservation solutions. Oxidative metabolism (measured by (13)C-enrichment of glutamate) and adenine nucleotide levels were quantified. Increasing preservation solution pyruvate concentration augmented glutamate (13)C-enrichment up to a concentration of 32mM pyruvate. DCA further stimulated oxidative metabolism only at lower concentrations of pyruvate (4 and 8mM). ATP and ADP were not different among groups, but AMP levels were higher in the glucose group. These data suggest that altering the substrate composition of the preservation solution influences lung metabolism during allograft preservation for transplantation. 相似文献
110.
Epinephrine (Epi) was previously found to bypass the need for galactose ligands during early steps in the initiation of Entamoeba encystment. Epinephrine is presumed to act on amoebae through a classical adrenergic signaling pathway that results in the increased production of cyclic adenosine monophosphate (cAMP). The object of this study was to verify the existence of an adrenergic like pathway and its response to Epi in both whole Entamoeba trophozoites and purified plasma membrane preparations. Whole trophozoite and purified membrane preparations from Entamoeba invadens responded to the presence of Epi by increasing the production of cAMP. The modulators of heterotrimeric G protein signaling, forskolin (FK), pertussis toxin (PTX) and cholera toxin (CTX), also increased cAMP levels in whole cells and membrane fragments. All of these increases in cAMP were inhibited by specific inhibitors of adenylyl cyclase (AC). Treatment of membrane fragments with epinephrine caused an increased binding of non-hydrolysable GTP analogs. Entamoeba trophozoites therefore appear to contain G-protein-regulated adenylyl cyclase that functions downstream of an adrenergic ligand receptor. 相似文献