全文获取类型
收费全文 | 525篇 |
免费 | 32篇 |
国内免费 | 66篇 |
专业分类
化学 | 582篇 |
综合类 | 13篇 |
数学 | 7篇 |
物理学 | 21篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 25篇 |
2021年 | 21篇 |
2020年 | 24篇 |
2019年 | 20篇 |
2018年 | 9篇 |
2017年 | 16篇 |
2016年 | 19篇 |
2015年 | 22篇 |
2014年 | 16篇 |
2013年 | 25篇 |
2012年 | 63篇 |
2011年 | 37篇 |
2010年 | 31篇 |
2009年 | 47篇 |
2008年 | 39篇 |
2007年 | 30篇 |
2006年 | 22篇 |
2005年 | 21篇 |
2004年 | 16篇 |
2003年 | 10篇 |
2002年 | 12篇 |
2001年 | 7篇 |
2000年 | 17篇 |
1999年 | 10篇 |
1998年 | 7篇 |
1997年 | 8篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 11篇 |
1993年 | 3篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有623条查询结果,搜索用时 15 毫秒
471.
Jing Ma Dai Li Bolu Sun Xiaohui Hou Xinru Zhang-Peng Wen Li Yan Zhang Fangdi Hu Xiaofeng Shi 《Electroanalysis》2022,34(4):761-771
The accurate and sensitive analysis of rheumatoid arthritis(RA) trace biomarkers is essential for early warning and diagnosis of RA, while anti-cyclic citrullinated peptide antibody (anti-CCP-ab) is a specific one. In this study, a simple label-free electrochemical immunosensor for the detection of anti-CCP-ab was constructed with nitrogen-doped graphene (N−G) and gold nanoparticles (AuNPs). The proposed non-enzyme immunosensor had exhibited high specificity, selectivity, and stability in the linear calibration curve range from 0.125∼2000 pg mL-1 and has been successfully used in the detection of anti-CCP-ab in human serum, providing a new idea for the early diagnosis of RA. 相似文献
472.
采用Endoproteinase Glu-C, Lys-C和Trypsin 3种蛋白酶分别水解β2-微球蛋白, 产生一系列肽段, 利用固定在琼脂糖珠上的单克隆抗体与其发生免疫亲和反应. 利用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)技术, 对抗原决定簇肽段-抗体复合物进行系统研究, 结果表明, 与抗体结合部位即连续表位的位点为肽段(59~69)(DWSFYLLYYTE). 该研究方法简便、准确, 可用来对其它抗原连续表位的快速测定. 相似文献
473.
Shen J Xu F Jiang H Wang Z Tong J Guo P Ding S 《Analytical and bioanalytical chemistry》2007,389(7-8):2243-2250
Quantum dot (Qdot) nanocrystals have been increasingly used as fluorescence labels in fluoroimmunoassays recently because
of their excellent optical characteristics. In this paper, a new monoclonal antibody (MAb) against sulfamethazine (SMZ) was
successfully produced and linked to Qdot nanocrystals by covalent coupling. The Qdot–MAb conjugates were characterized by
SDS-PAGE and high-performance capillary electrophoresis (HPCE). An enzyme-linked immunosorbent assay (ELISA) method was utilized
to evaluate the antigen–antibody binding affinity and then a novel direct competitive fluorescence-linked immunosorbent assay
(cFLISA) for the detection of SMZ in milk by using Qdots as fluorescent labels was evaluated. The results showed that the
50% inhibition values (IC50) of the cFLISA were 4.3 ng/mL in milk and 5.2 ng/mL in PBS, and the limits of detection (LODs) were 0.6 ng/mL in milk and
0.4 ng/mL in PBS, respectively. The recoveries of SMZ from spiked milk samples at levels of 10–100 ng/mL ranged from 94 to
106%, with coefficients of variation (CVs) of 2.1–9.2%.
Figure Shematic diagram of the direct cFLISA procedure
Jianzhong Shen and Fei Xu contributed equally to this work. 相似文献
474.
Enzyme-linked immunosorbent assay (ELISA) using a specific monoclonal antibody as a new tool to detect Sudan dyes and Para red 总被引:1,自引:0,他引:1
To set up an immunoassay-based method to detect Sudan dyes and Para red, we generated a monoclonal antibody (Mab) using a specially designed carboxyl derivative of Sudan I (CSD I) as the immunogen. CSD I was synthesized by azocoupling reaction using 2-naphthol and diazotised 4-aminobenzoic acid. The antibody was obtained from a hybridoma, which was derived from the fusion of the mouse myeloma SP2/0 cells and the splenocytes from the mice immunized with the CSD I-bovine serum albumin (BSA) conjugate. In addition, we showed that the Mab was highly specific for Sudan I, III and Para red. The limit of detection was approximately 0.01 ng mL−1 in phosphate-buffered saline (PBS) buffer and 0.5 ng g−1 in chilli tomato sauce. The recoveries of Sudan I, III and Para red for the chilli tomato sauce were from 84% to 99% and coefficients of variation were from 14.9% to 33.3%. Thus, the enzyme-linked immunosorbent assay (ELISA) method is a rapid and high throughput screening tool to detect Sudan dyes and Para red in food products. 相似文献
475.
Magdalena Boncler 《Macromolecular bioscience》2023,23(7):2300052
A commercial nonbinding surface effectively prevents protein adsorption; however, the platelet phenotype on this surface has yet to be defined. This study evaluates platelet adhesion and adsorption of several plasma/extracellular matrix (ECM) proteins to the nonbinding surface compared to other commonly used nontreated and high-binding surfaces. Platelet adhesion to uncoated microplates and those coated with fibrinogen or collagen is quantified by colorimetric assay. The binding capacity of the examined surfaces for plasma/ECM proteins is evaluated by measuring the relative and absolute protein adsorption. Compared to other surfaces, the nonbinding surface effectively prevents platelet adsorption, i.e. by 61-93% (Enzyme-Linked Immunosorbent Assay, ELISA), and reduces platelet adhesion, i.e. by 92%, when not coated with any protein. The nonbinding surface also decreases platelet deposition on collagen (up to 31%), but not fibrinogen. The nonbinding surface seems to be more of a low-fouling than nonfouling material, as it is able to reduce fibrinogen adsorption but not prevent platelet adhesion to fibrinogen. This feature should be considered when using the nonbinding surface for in vitro platelet testing. 相似文献
476.
本实验建立了表面等离子体共振(SPR)生物传感器检测3-吲哚乙酸(IAA)的方法。制备了两种SPR生物传感器检测IAA:传统模式的SPR生物传感器1和Au/Ag合金纳米粒子增敏的SPR生物传感器2。结果发现:传感器1在IAA浓度范围为175~350μg/L时,浓度与其波数位移值呈线性关系,检出限为25μg/L(S/N=3);传感器2在IAA浓度范围为17.5~250μg/L时,浓度与其波数位移值呈线性关系,检出限为2.2μg/L(S/N=3)。说明基于Au/Ag合金纳米粒子的传感器2比传感器1有较高的灵敏度和较低的检出限。加标回收实验测得加标回收率范围为96%~100.2%,平均值为98.4%。本实验制备的SPR生物传感器具有较好的精密度、稳定性、重现性和特异性。 相似文献
477.
Cong Ying Shi Ning Deng Jia Jie Liang Ke Nan ZhouQiang Qiang Fu Yong Tang 《Analytica chimica acta》2015
A fluorescent polymer dots positive readout and sensitive lateral flow assay (LFA) based on fluorescent quenching has been developed to detect ractopamine (Rac), a chemical residue in food, harmful to human health. Compared with traditional LFA strips, these fluorescent quenching LFA (FQLFA) strips provide a positive correlation method that allows users to obtain results from a weak fluorescent signal. The immunoassay strip scheme is based on the fact that fluorescent polymer dots (FPDs) in close proximity to gold nanoparticles (AuNPs) represent a strong fluorescent quenching. We show that the FQLFA strips can be used as a source to quantitatively analyze Rac in phosphate buffers (PB), swine urine and muscle tissue samples. The lowest detection limitation of the FQLFA was 0.16 ng mL−1. Our results indicated that this novel scheme was more suitable for rapid detection of small molecules. 相似文献
478.
Luciana I.N. Tomé Nuno V. Marques Victor C. Diculescu Ana Maria Oliveira-Brett 《Analytica chimica acta》2015
The interaction of the anticancer monoclonal antibody bevacizumab (BEVA) with double-stranded DNA (dsDNA) was studied by voltammetry and gel-electrophoresis in incubated samples and using the dsDNA-electrochemical biosensor. The voltammetric results revealed a decrease and disappearance of the dsDNA oxidation peaks with increasing incubation time, showing that BEVA binds to the dsDNA but no DNA oxidative damage was detected electrochemically. Non denaturing agarose gel-electrophoresis experiments were in agreement with the voltammetric results showing the formation of compact BEVA-dsDNA adduct. The dsDNA-electrochemical biosensor in incubated solutions showed that BEVA also undergoes structural modification upon binding dsDNA, and BEVA electroactive amino acid residues oxidation peaks were detected. 相似文献
479.
Cutting‐edge mass spectrometry characterization of originator,biosimilar and biobetter antibodies
下载免费PDF全文
![点击此处可从《Journal of mass spectrometry : JMS》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A. Beck F. Debaene H. Diemer E. Wagner‐Rousset O. Colas A. Van Dorsselaer S. Cianférani 《Journal of mass spectrometry : JMS》2015,50(2):ii-ii
The approval process for antibody biosimilars relies primarily on comprehensive analytical data to establish comparability and high similarity with the originator. Mass spectrometry (MS) in combination with liquid chromatography (LC) and electrophoretic methods are the corner stone for comparability and biosimilarity evaluation. In this special feature we report head‐to‐head comparison of trastuzumab and cetuximab with corresponding biosimilar and biobetter candidates based on cutting‐edge mass spectrometry techniques such as native MS and ion‐mobility MS at different levels (top, middle and bottom). In addition, we discuss the advantages and the limitations of sample preparation and enzymatic digestion, middle‐up and ‐down strategies and the use of hydrogen/deuterium exchange followed by MS (HDX‐MS). Last but not least, emerging separation methods combined to MS such as capillary zone electrophoresis‐tandem MS (CESI‐MS/MS), electron transfer dissociation (ETD), top down‐sequencing (TDS) and high‐resolution MS (HR‐MS) that complete the panel of state‐of‐the‐art MS‐based options for comparability and biosimilarity evaluation are presented. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
480.
A Phosphorylation‐Induced Turn Defines the Alzheimer’s Disease AT8 Antibody Epitope on the Tau Protein
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Neha S. Gandhi Dr. Isabelle Landrieu Dr. Cillian Byrne Dr. Predrag Kukic Dr. Laziza Amniai Dr. François‐Xavier Cantrelle Dr. Jean‐Michel Wieruszeski Dr. Ricardo L. Mancera Dr. Yves Jacquot Dr. Guy Lippens 《Angewandte Chemie (International ed. in English)》2015,54(23):6819-6823
Post mortem biochemical staging of Alzheimer’s disease is currently based on immunochemical analysis of brain slices with the AT8 antibody. The epitope of AT8 is described around the pSer202/pThr205 region of the hyperphosphorylated form of the neuronal protein tau. In this study, NMR spectroscopy was used to precisely map the AT8 epitope on phosphorylated tau, and derive its defining structural features by a combination of NMR analyses and molecular dynamics. A particular turn conformation is stabilized by a hydrogen bond of the phosphorylated Thr205 residue to the amide proton of Gly207, and is further stabilized by the two Arg residues opposing the pSer202/pThr205. 相似文献