全文获取类型
收费全文 | 206篇 |
免费 | 10篇 |
专业分类
化学 | 170篇 |
力学 | 4篇 |
数学 | 25篇 |
物理学 | 17篇 |
出版年
2023年 | 1篇 |
2022年 | 10篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 4篇 |
2013年 | 10篇 |
2012年 | 15篇 |
2011年 | 11篇 |
2010年 | 11篇 |
2009年 | 9篇 |
2008年 | 19篇 |
2007年 | 20篇 |
2006年 | 10篇 |
2005年 | 14篇 |
2004年 | 11篇 |
2003年 | 7篇 |
2002年 | 8篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1989年 | 1篇 |
1984年 | 1篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1941年 | 1篇 |
1926年 | 1篇 |
1913年 | 1篇 |
1869年 | 1篇 |
排序方式: 共有216条查询结果,搜索用时 15 毫秒
211.
A rapid and sensitive 384-microtiter wells format chemiluminescent enzyme immunoassay for clenbuterol 总被引:2,自引:0,他引:2
A fast and sensitive chemiluminescent (CL) enzyme immunoassay for clenbuterol (CLB) analysis in bovine urine has been developed. Clenbuterol (CLB) specific polyclonal antibodies were raised in rabbit using a CLB azo derivative conjugated with ovalbumin. Horseradish peroxidase (HRP) was used as label and conjugated with the same derivative. In the developed competitive method, antibodies were immobilized on 384-wells black polystyrene microtiter plates; the sample volume was 20 mul and HRP-labeled CLB activity was immediately measured, using different CL substrates, after 10 min incubation time. Emitted light was recorded using a sensitive back-illuminated, cooled CCD camera or a conventional, photomultiplier-based micrtotiter plate reader. The developed method fulfills all the requirements of precision (CV below 10%) and accuracy (mean recovery from 96 to 110%) with a detection limit of 0.08 ppb in urine matrix. The use of 384-wells microtiter plate allows a 5-fold reduction in reagent quantity and the CL detection improves the detectability of the HRP-labeled tracer, thus reducing analysis time. The developed method is therefore suitable for high-throughput screening of CLB in urine samples, with reduced costs as compared with conventional colorimetric enzyme immunoassays, thanks to the possibility to optimize the system in non-equilibrium immunological conditions and with a very fast chemiluminescence detection of the HRP-label activity. 相似文献
212.
Letizia Pontoriero Marco Schiavina Dr. Maria Grazia Murrali Prof. Roberta Pierattelli Prof. Isabella C. Felli 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(42):18696-18704
Many properties of intrinsically disordered proteins (IDPs), or protein regions (IDRs), are modulated by the nature of amino acid side chains as well as by local solvent exposure. We propose a set of exclusively heteronuclear NMR experiments to investigate these features in different experimental conditions that are relevant for physiological function. The proposed approach is generally applicable to many IDPs/IDRs whose assignment is available in the Biological Magnetic Resonance Bank (BMRB) to investigate how their properties are modulated by different, physiologically relevant conditions. The experiments, tested on α-synuclein, are then used to investigate how α-synuclein senses Ca2+ concentration jumps associated with the transmission of nerve signals. Novel modules in the primary sequence of α-synuclein optimized for calcium sensing in highly flexible, disordered protein segments are identified. 相似文献
213.
In the last years several authors have used Lubich convolution quadrature formulas to discretize space-time boundary integral
equations representing time dependent problems. These rules have the fundamental property of not using explicitly the expression
of the kernel of the integral equation they are applied to, which is instead replaced by that of its Laplace transform, usually
given by a simple analytic function. In this paper, a review of these rules, which includes their main properties, several
new remarks and some conjectures, will be presented when they are applied to the heat and wave space-time boundary integral
equation formulations. The construction and behavior of the corresponding coefficients are analyzed and tested numerically.
When the quadrature is defined by a BDF method, a new approach for the representation of its coefficients is presented. 相似文献
214.
Lepore L Gualtieri MJ Malafronte N Cotugno R Dal Piaz F Ambrosio L De Falco S De Tommasi N 《Natural product communications》2011,6(7):943-946
Angiogenesis is a crucial step in many pathological conditions like cancer, inflammation and metastasis formation; on these basis the search for antiangiogenic agents has widened. In order to identify new compounds able to interfere in the Vascular Endothelial Growth Factor Receptor-1 (VEGFR-1, also known as Flt-1) recognition by VEGFs family members, we screened Calycolpus moritzianus (O. Berg) Burret leaves extracts by a competitive ELISA-based assay. MeOH and CHCl3 extracts and several their fractions demonstrated to be able to prevent VEGF or PlGF interaction with Flt-1, with an inhibition about 50% at concentration of 100 microg/mL. Phytochemical and pharmacological investigation of the active fractions led to the isolation of flavonoids, and terpenes. 相似文献
215.
216.