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
541.
Agnes Voitl Thomas Müller-Späth Massimo Morbidelli 《Journal of chromatography. A》2010,1217(37):5753-5760
The downstream processing of monoclonal antibodies from cell culture supernatant is usually done by a number of chromatographic and non-chromatographic steps. Efforts are taken to reduce the costs associated to those steps, while maintaining a high product purity. A possibility to reach this goal is the reduction of the number of chromatographic steps using mixed mode resins that offer more than one functionality in one chromatographic step. In this work, a commercially available mixed mode resin was evaluated systematically with respect to the adsorption of proteins. The Henry coefficient, which quantifies the adsorption strength, was measured for the full working range of the stationary phase as a function of the salt concentration and the pH. The results were compared to a conventional anion exchange and a hydrophobic interaction resin. Furthermore, the resin was applied for the polishing step of an antibody from an industrial clarified cell culture supernatant. 相似文献
542.
543.
Hye-Weon Yu Jinwook Lee Sungyoun Kim Giang Huong Nguyen In S. Kim 《Analytical and bioanalytical chemistry》2009,394(8):2173-2181
The presence of cyanobacterial hepatotoxins such as microcystin-LR poses health threats to humans due to their potential for
causing severe physiological effects when contaminated drinking water is ingested. Here, the electrochemical detection of
microcystin-LR is explored using a quantum dot/antibody (QD/Ab) probe for nanoparticle-based amplification and direct electrochemical
transduction. The immunological recognition of microcystin-LR using the QD/Ab probe was amplified and converted to an electrochemical
signal by measuring the cadmium ions released from QD based on square wave stripping voltammetry under optimized electrochemical
factors. Whereas a qualitative analysis for microcystin-LR was achieved using the specific peak potential of the anodic voltammogram
at −0.6 ± 0.05 V, concentration of the toxin was quantified based on the charge density of the anodic peak; a dynamic range
of 0.227 to 50 μg/L and limit of detection of 0.099 μg/L were obtained with high sensitivity. The extracted microcystin-LR
from Microcystis aeruginosa was estimated as 1,944 μg/g of dried weight of the microorganism. 相似文献
544.
Kunio Nakanishi Daisuke Nakata Mayuko Konishi Yukiko Uekaji Keiji Terao 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):61-64
Itching dermatitis, which is very similar to human atopic dermatitis, arises spontaneously in NC/Nga mice. Changes in lesional
skin and the plasma concentration of IgE during the development of atopic dermatitis-like disease up to 8 weeks after the
start of picryl chloride (PiCl) in NC/Nga mice were examined. In the mice which atopic dermatitis had been induced, 28-day
administration of α cyclodextrin (α CD) significantly inhibited aggravation of detmatitis without having effects on body weight.
Clinical signs and symptoms seen in PiCl treated NC/Nga mice began with erythema and haemorrhage, following oedema, superficial
erosion, deep excoriation, scaling and dryness of the skin. An increase was observed in the number of mast cells and eosinophil
infiltration in the lesional skin. Almost human patients with nasal inflammation or bronchial asthmatics symptoms disappeared
by oral administration of α CD (5 mg/day) for 2 month. These results suggest that α CD is useful for treatment of human atopic
dermatitis. 相似文献
545.
M. S. Neuberger J. E. Sale S. J. Cumbers C. J. Jolly M. P. Bemark M. R. Ehrenstein A. Lanoue M. Brüggemann F. D. Batista S. L. Davies G. T. Williams 《Applied biochemistry and biotechnology》2000,83(1-3):53-62
The physiological mechanism for producing antigen-specific antibodies is based on a two-phase neo-Darwinian process: the first
phase consists of diversity generation (formation of the repertoire), and the second phase is antigen-mediated selection.
In this article, we consider how the natural immunoglobulin gene-diversification processes can be exploited both in vivo and
in vitro in order to allow the generation of novel antibody (and heterologous protein) repertoires. 相似文献
546.
Agnes Franke Nicola Forrer Alessandro Butté Božidar Cvijetić Massimo Morbidelli Matthias Jöhnck Michael Schulte 《Journal of chromatography. A》2010,1217(15):2216-2225
The performance of functionalized materials, such as cation exchange resins, is dependent not only on the ligand type and ligand density, but also on the pore accessibility of the target molecule. In the case of large molecules such as antibodies this latter parameter becomes crucial, because the size of such molecules falls somewhere inside the pore size distribution of the resin. The influence of the ligand density and accessibility on the overall performance of the material is explored systematically. Five different materials, having the same chemistry as the strong cation exchange resin Fractogel EMD SO3− (M) , have been analyzed. These materials only differ in the ligand density. It is shown that the ligand density directly influences the porosity of the materials as well as the pore diffusivity and the dynamic binding capacity. For a given purification problem an optimal ligand density can be found. Based on the above results a new material is proposed, showing superior properties in terms of dynamic binding capacity. This is achieved by an optimization of the ligand density and by a decrease of the particle size of the stationary phase. The material properties are modeled with a general rate model. Further simulations were conducted to evaluate the performance of the new material in comparison with a conventional resin. 相似文献
547.
合成了半抗原烯效唑琥珀酸半酯,分别将半抗原与牛血清蛋白(BSA)和卵清蛋白(OVA)偶联制备了免疫抗原和包被抗原,并成功建立了水和土壤中烯效唑残留的酶联免疫吸附分析法。用免疫抗原免疫新西兰大白兔得到多克隆抗体,抗体的效价达到1.02×106。方法的线性范围为0.005~10mg/L,检出限为1.82±0.83μg/L。除烯唑醇有一定的交叉反应外,与大部分三唑类杀菌剂都没有明显的交叉反应。在水和土壤中添加不同浓度的烯效唑,回收率分别在82.40%~105.92%和92.42%~100.08%之间。 相似文献
548.
Anna Rozhkova 《Journal of chromatography. A》2009,1216(32):5989-5994
A robust cation-exchange chromatofocusing method was developed for the routine analysis of a recombinant humanized monoclonal IgG antibody. We compare the chromatofocusing method to the conventional cation-exchange chromatography (CEX) employing a salt gradient and show clear advantages of chromatofocusing over CEX. We demonstrate the suitability of the present chromatofocusing method for its intended purpose by testing the validation characteristics. To our knowledge, this is the first chromatofocusing method developed for the routine analysis of monoclonal antibody charge species. 相似文献
549.
Bubble cells have been frequently employed in capillary electrophoresis (CE) to increase the light path length with UV detection to provide an increase in the observed sensitivity of CE; however this approach has not been commonly used for laser-induced fluorescence detection (LIF) with CE. In this paper we study the influence of laser power on the sensitivity of detection in using conventional and enlarged fused silica capillaries for CE with LIF. When using the bubble cell capillary, the laser power must be decreased relative to use of the conventional capillary to reduce the effects of photodegradation of the species being illuminated by the laser. Even though the light intensity was decreased, an increase in sensitivity of detection was observed for most compounds when a bubble cell was used. This increase ranged from a factor of 8 for riboflavin (410 nm excitation) to 3.2 for most aromatic compounds (266 nm excitation), when using a 3x bubble cell compared with a conventional capillary. The bubble cell capillary was used for native detection of IgG by LIF at 266 nm. A limit of detection of 60 ng mL(-1) was obtained from a 20 pg injection, which was 40 times more sensitive than silver staining in conventional SDS/PAGE. 相似文献
550.
New highly sensitive enzyme immunoassay (EIA) has been developed and validated for the determination of pravastatin (PRV) in human plasma samples. PRV was coupled to keyhole limpt hemocyanin (KLH) and bovine serum albumin (BSA) via its terminal carboxylic acid group by carbodiimide reagent. PRV-KLH conjugate was used as an immunogen for raising anti-PRV polyclonal antibody in rabbits. The generated anti-PRV antibody recognized PRV with high affinity and selectivity. PRV-BSA conjugate was immobilized onto microwell plates and used as a solid phase. The assay involved a competitive binding reaction between PRV, in plasma sample, and the immobilized PRV-BSA for the binding sites on a limited amount of the anti-PRV antibody. The anti-PRV antibody bound to the plate wells was quantified with horseradish peroxidase-labeled anti-immunoglobulin second anti-rabbit IgG antibody and 3,3′,5,5′-tetramethylbenzidine as a substrate for the peroxidase enzyme. The concentration of PRV in the sample was quantified by its ability to inhibit the binding of the anti-PRV antibody to the immobilized PRV-BSA and subsequently the color development in the assay wells. The conditions of the proposed EIA were investigated and the optimum conditions were employed in the determination of PRV in plasma samples. The assay limit of detection was 0.2 ng mL−1 and the effective working range at relative standard deviation (RSD) of ≤5% was 0.5-20 ng mL−1. The mean analytical recovery of PRV from spiked plasma was 100.9 ± 2.98%. The precision of the assay was satisfactory; RSD was 2.61-3.70 and 3.96-4.17% for intra- and inter-assay precision, respectively. The analytical procedure is convenient, and one can analyze ∼200 samples per working day, facilitating the processing of large-number batch of samples. The proposed EIA has a great value in the routine analysis of PRV in plasma samples for its therapeutic monitoring and pharmacokinetic studies. 相似文献