全文获取类型
收费全文 | 16652篇 |
免费 | 1169篇 |
国内免费 | 533篇 |
专业分类
耳鼻咽喉 | 40篇 |
儿科学 | 390篇 |
妇产科学 | 322篇 |
基础医学 | 2191篇 |
口腔科学 | 300篇 |
临床医学 | 1741篇 |
内科学 | 2052篇 |
皮肤病学 | 186篇 |
神经病学 | 629篇 |
特种医学 | 284篇 |
外国民族医学 | 2篇 |
外科学 | 809篇 |
综合类 | 2828篇 |
现状与发展 | 1篇 |
预防医学 | 1202篇 |
眼科学 | 173篇 |
药学 | 3063篇 |
17篇 | |
中国医学 | 1290篇 |
肿瘤学 | 834篇 |
出版年
2023年 | 145篇 |
2022年 | 268篇 |
2021年 | 493篇 |
2020年 | 476篇 |
2019年 | 450篇 |
2018年 | 432篇 |
2017年 | 534篇 |
2016年 | 560篇 |
2015年 | 512篇 |
2014年 | 937篇 |
2013年 | 1116篇 |
2012年 | 847篇 |
2011年 | 1039篇 |
2010年 | 790篇 |
2009年 | 648篇 |
2008年 | 650篇 |
2007年 | 702篇 |
2006年 | 696篇 |
2005年 | 595篇 |
2004年 | 547篇 |
2003年 | 500篇 |
2002年 | 432篇 |
2001年 | 332篇 |
2000年 | 286篇 |
1999年 | 210篇 |
1998年 | 226篇 |
1997年 | 226篇 |
1996年 | 199篇 |
1995年 | 207篇 |
1994年 | 216篇 |
1993年 | 206篇 |
1992年 | 197篇 |
1991年 | 171篇 |
1990年 | 158篇 |
1989年 | 156篇 |
1988年 | 128篇 |
1987年 | 149篇 |
1986年 | 99篇 |
1985年 | 345篇 |
1984年 | 262篇 |
1983年 | 232篇 |
1982年 | 198篇 |
1981年 | 180篇 |
1980年 | 135篇 |
1979年 | 89篇 |
1978年 | 83篇 |
1977年 | 65篇 |
1976年 | 48篇 |
1975年 | 39篇 |
1973年 | 30篇 |
排序方式: 共有10000条查询结果,搜索用时 144 毫秒
101.
目的 根据小鼠神经元与T淋巴细胞具有共同抗原Thy-1的特点,利用鼠脑组织制备兔抗鼠T淋巴细胞血清。方法 提取鼠脑组织与弗氏完全佐剂混合,制成油包水乳剂, 免疫2只家兔后,采血,分离血清,用鼠脾淋巴细胞做凝集试验及补体依赖的细胞毒试验确定其活性。结果 制备的抗血清可与鼠脾淋巴细胞发生反应,2只兔抗血清凝集试验的效价分别为1:640及1:1280。抗血清1:320倍稀释后与鼠脾淋巴细胞做补体依赖的细胞毒试验,特异性细胞毒性均为32%。结论 用鼠脑组织制备抗鼠T淋巴细胞血清是一种可行的方法。 相似文献
102.
Eduardo M. B. Tinoco Ståle P. Lyngstadaas Hans R. Preus Per Gjermo 《Journal of clinical periodontology》1997,24(12):937-944
Abstract Immunological data have been suggested to be a potential tool in the diagnosis, classification and monitoring of periodontal diseases. However, the role of circulating antibodies in periodontal patients is poorly understood. Patients suffering from localized juvenile periodontitis (LJP) are often reported to show high titers of serum IgG antibodies against Aetinobaeillus actinomycetemcomitans (A. actinomycetemcotnitans), but several affected patients do not. Most studies use well-known reference strains of the bacterium for testing against the patients' sera. The aim of the present investigation was to study the relationship between serum IgG antibody levels to autologous A. actinomycetemcomitans strains and clinical attachment loss (CAL). In addition, we wanted to assess the patients’serum titers against 4 well-known reference strains of the bacterium as well as their general potential immunoglobulin response. Intravenous blood samples were taken from 23 LJP patients and 10 healthy individuals, and autologous A. actinomycetemcomitans strains were cultured from 18 of the L.JP patients. CAL was measured at 4 different sites around ail present teeth and assessed as a % of teeth with at least 1 site moderately ≥2<5 mm) or severely (≥5 mm) involved. An enzyme-linked immunosorbent assay (ELISA) was performed to evaluate the serum titers of IgG antibodies to A. actinomycetemcomitans antigens. No significant correlation was found between serum IgG antibody titers to autologous strains and CAL. However, there was a trend that low responders had more moderately affected teeth than had high responders and patients with undetectable A. actinomycetemcomitans levels, which is in agreement with a hypothetically protective role of the antibodies. The total counts of immunoglobulin assessed in all participants showed that the predominant class was IgG and the reference group displayed significantly less (p<0.05) IgG and IgG1 counts than the LJP patients. Both the reaction pattern against reference and autologous strains varied widely. We conclude that the specific antibody response against A. actinomycetemcomitans shows a weak correlation to clinical attachment levels in LJP patients. 相似文献
103.
β-N-Acetylhexosaminadases in human cerebrospinal fluid and serum of patients with multiple sclerosis
Alessandro Datti Carla Emiliani Giuseppe Capocchi Aldo Orlacchio 《Clinica chimica acta; international journal of clinical chemistry》1991,200(2-3)
β-N-Acetylhexosaminidase activity and isoenzyme have been investigated in normal human cerebrospinal fluid and that of patients with multiple sclerosis. β-N-acetylhexosaminidase activity in normal cerebrospinal fluids has been resolved into five components. The major component was in a form that eluted from DEAE cellulose at the same salt concentration as hexosaminidase As, the isoenzyme previously identified in human serum. Cerebrospinal fluid from patients exhibited a different isoenzyme profile, showing a remarkable increase in a form having a pI which was more acidic than that of As. These changes have a potential use in the diagnosis and further biochemical characterization of multiple sclerosis. 相似文献
104.
G. Seghieri G. C. Bartolomei L. A. De Giorgio F. Innocenti A. Gironi M. Mian F. Franconi 《European journal of clinical pharmacology》1989,37(4):401-404
Summary Serum digoxin and beta-methyldigoxin (BMD) were measured in 165 elderly patients (age >60 years) admitted to hospital, of whom 109 had been treated at home with digoxin and 56 with BMD.The mean BMD level was significantly lower than that of digoxin (1.1 vs. 1.4 ng/ml). Creatinine clearance and daily dose were the variables most strongly associated with digoxin level, and the prescribed dose and serum albumin were the best predictors of the BMD concentration. Compliance was assessed by a compliance index (CI), namely the ratio of the measured glycoside concentration, corrected for creatinine clearance, over the expected steady-state dose, calculated from a hospitalized reference group. Compliant individuals in both treatment groups, i.e. those with a CI > the median value, were characterized by a lower daily dose and dosage frequency.Toxicity, whether clinical or electrocardiographic, was present in 9% of the patients and was associated only with a significantly higher mean serum level of the drug. 相似文献
105.
The Effects of Serum from Patients with Acute Liver Failure on the Growth and Metabolism of Hep G2 Cells 总被引:6,自引:0,他引:6
In many bioartificial liver systems currently being designed and evaluated for use in fulminant hepatic failure, direct contact is required between the patient's blood and the liver cells in the device. The efficacy of such devices will be influenced by the interaction of fulminant hepatic failure (FHF) patient serum with the cells. We have found that FHF serum inhibits the growth rate and the synthesis of DNA, RNA, and protein; disturbs glutathione homeostasis; and induces morphological changes in cultured human Hep G2 cells. These interactions should influence the design of bioartificial liver devices based on proliferating cell lines and indicate the requirement to pretreat FHF patient plasma to reduce the toxin load. 相似文献
106.
Fungal contamination of agricultural commodities leads to their spoilage and renders them unfit for human consumption. Ergosterol, a predominant sterol in most fungi and a major constituent of the cell membrane, has been established as a reliable biochemical marker for fungal growth. Various chemical and physico‐chemical methods to quantify ergosterol as an index of fungal contamination are in practice. Yet, immunoassays are the methods of choice in food analysis due to their increased specificity, sensitivity and rapidity. This paper reports the synthesis of an antigen, bovine serum albumin‐ergosterol conjugate, and its immunocharacterization. Ergosterol was converted to ergosterol hemisuccinate (EHS) by succinylation. Subsequently, EHS was conjugated to bovine serum albumin by the mixed anhydride reaction. The molar ratio was found to be 1:28. Antisera raised against the synthesized antigen in rabbits was characterized by the Ouchterlony double‐diffusion technique and an antibody capture assay. Ouchterlony analysis showed a titre of 1:2. Further, characterization by an antibody capture assay, using 50 ng well (10 ng equivalent of ergosterol) of the antigen, gave a titre of 1:4000 dilution of antiserum, with an absorbance of 1.0 at 405 nm. The synthesized antigen may find an application in the development of an immunoanalytical method for ergosterol quantification as a measure of food quality in relation to fungal contamination. 相似文献
107.
急性心肌梗塞患者血清唾液酸含量测定 总被引:2,自引:0,他引:2
本文测定了50例正常人,32例急性心肌梗塞,54例冠心病无梗塞者血清SA水平,结果表明,急性心肌梗塞组血清SA水平与冠心病无梗塞组及正常人相比,具显著性差异,可能与心肌梗塞造成心肌细胞受损所致使细胞表面成份释放入血有关,所以血清SA测定可提供一新的心肌梗塞诊断依据。 相似文献
108.
玉米油和猪油对大鼠血脂血糖代谢和脑脂褐质影响的比较研究 总被引:5,自引:0,他引:5
采用幼年SD雄性大鼠30只,体重150±20g,随机分成三组,每组10只:(1)基础饲料组:普通大鼠饲料;(2)猪油组:基础饲料中加入10%猪油和1.5%胆固醇;(3)玉米油组:在基础饲料中加入10%玉米油和1.5%胆固醇,饲养9周,比较玉米油和猪油对大鼠血脂血糖和脑脂褐质的不同影响。结果表明,玉米油组TC和LDL-C水平较猪油组低,虽然两组均高于基础饲料组。玉米油组的HDL-C比猪油升高不显著,但HDL-C/TC(%)增加,同时LDL-C/HDL-C比值下降。基础饲料组,猪油组和玉米油组的大鼠平均血清TG分别为1.28,1.21和1.45(mmol/L),各组之间的差别不显著。高脂饲料组动物的空腹血糖(SG)较基础饲料组高,但差别无统计学意义。三组不同饲料大鼠的脑脂褐质(LPF)含量测定结果显示:基础饲料组大鼠的LPF平均值12.9U/g蛋白质,而玉米油组和猪油组均明显升高,分别为28.3和28.8U/g蛋白质。在以血脂各项指标为自常量,大脑LPF含量为因变量的相关分析中发现,LPF与TC和LDL-C呈正相关,相关系数分别为0.691和0.547,P<0.01. 相似文献
109.
本文对82名12~15岁、体重35~45kg的农村初中学生进行了维生素A、β-胡萝卜素的补充实验研究。实验1组(n=21)每天补充2mg的β-胡萝卜素,实验2组(n=19)每天补充6mg的β-胡萝素,实验3组(n=24)每天补充400μgRE维生素儿分别在实验初始、第四周末、第六周末和第八周末抽血测定。在实验的第七周,将补胡萝卜素的两组改为补维生素A1000μgRE、补维生素A组改为补6mg的β-胡萝卜素。对照组(n=18)给予安慰剂。结果显示:每天摄入营养素推荐摄入量(RDA)剂量和2倍RDA剂量的β-胡萝卜素,对于提高机体维生素A、β-胡萝卜素水平的效果是相同的,而直接补充维生素A,机体维生素A、β-胡萝卜、素水平略高于补胡萝卜素组。本研究探讨了我国青少年确实的营养状况,也提示维生素A在维生素A营养中具有胡萝卜素不可替代的作用。 相似文献
110.
目的 :研究体外制备的糖基化产物引起肾脏的自由基损伤。方法 :给正常大鼠静脉注射体外制备的糖基化血清蛋白 (GSP) 2个月 ,观察 GSP对肾脏自由基代谢的影响。结果 :GSP处理的大鼠肾脏糖基化终末产物 (AGE)浓度和 NBT染色强度明显高于对照组。与对照组比较 ,接受 GSP的大鼠肾脏超氧化物歧化酶 (SOD)和过氧化氢酶 (CAT)活性明显降低 ,尿液脂质过氧化物 (MDA)水平显著升高。结论 :外源性 GSP可引起正常大鼠肾脏自由基代谢紊乱 ,糖基化产物的致病作用部分是由氧化应激损伤引起的 相似文献