全文获取类型
收费全文 | 157篇 |
免费 | 6篇 |
国内免费 | 6篇 |
专业分类
化学 | 52篇 |
力学 | 13篇 |
综合类 | 1篇 |
数学 | 60篇 |
物理学 | 43篇 |
出版年
2024年 | 1篇 |
2022年 | 3篇 |
2021年 | 1篇 |
2020年 | 5篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 7篇 |
2014年 | 6篇 |
2013年 | 9篇 |
2012年 | 14篇 |
2011年 | 24篇 |
2010年 | 10篇 |
2009年 | 3篇 |
2008年 | 8篇 |
2007年 | 10篇 |
2006年 | 6篇 |
2005年 | 11篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有169条查询结果,搜索用时 31 毫秒
2.
酶联免疫吸附分析法测定水样中的阿特拉津 总被引:18,自引:0,他引:18
应用阿特拉津半抗原衍生物共价交联于载体蛋白分子上,制成免疫抗原,经免疫得到高质量的兔抗阿特拉津抗血清。经条件优选,建立了测定阿特拉津的酶联吸附分析竞争法,测定性范围为0.05-5.00μg/L,最低检出限仅为0.018-0.022μg/L,且精密度高,特异性强。 相似文献
3.
In this paper, the singular value decompositions of anti-symmetric matrices and anti-bisymmetric matrices are presented, and a class of parameterized inverse singular value problem for anti-bisymmetric matrices is solved. Numerical examples which confirm our theory are presented. 相似文献
4.
The use of Sudan I as an additive in food products has been prohibited in the European Union and many other countries. In this study, a highly sensitive and specific monoclonal antibody (mAb)-based indirect competitive enzyme-linked immunosorbent assay (ELISA) for the detection of Sudan I in food samples was developed. The hapten derivative with a three-carbon-atom length of carboxylic spacer at the azobound para-position was synthesized and coupled to carrier proteins. The hapten-bovine serum albumin (BSA) conjugate was used as an immunogen, while the hapten-ovalbumin (OVA) conjugate was applied as a coating antigen. The mAb against Sudan I was produced by hybridoma technique and the corresponding ELISA was characterized in terms of sensitivity, specificity, precision and accuracy. At optimal experimental conditions, the standard curve was constructed in concentrations of 0.1-100 ng mL−1. The values of IC50 for nine standard curves were in the range of 1.1-2.0 ng mL−1 and the LOD at a signal-to-noise ratio of 3 (S/N = 3) was 0.07-0.14 ng mL−1. The cross-reactivity values of the mAb with Sudan II, III and IV were 9.5%, 33.9% and 0.95%; no cross-reactivity was found with other six edible colorants: Lemon yellow, Bright blue, Indigotin, Kermes, Amarant and Sunset yellow, indicating the assay displays not only high sensitivity but also high specificity as well. The organic solvent effect on the assay was tested. It was observed that the ELISA was tolerated to 30% of methanol and 10% of acetonitrile without significant loss of IC50 value. Six food samples were spiked with Sudan I and the methanolic extracts after appropriate dilution were analyzed by ELISA. Acceptable recovery rates of 88.2-110.5% and coefficients of variation of 2.5-17.4% were obtained. The ELISA for nine spiked samples was confirmed by high-performance liquid chromatography (HPLC) with a high correlation coefficient of 0.9840 (n = 9). The mAb-based ELISA proven to be a feasible quantitative/screening method for Sudan I analysis in food samples with the properties of high sensitivity, specificity, simplicity of sample pretreatment, high sample throughput and low expense. 相似文献
5.
6.
The establishment of an immunoaffinity chromatography (IAC) for simultaneously selective extraction of four illegal colorants Sudan dyes (Sudan I, II, II and IV) from food samples was described. The IAC column was constructed by covalently coupling monoclonal antibody (mAb) against Sudan I to CNBr-activated Sepharose 4B and packed into a common solid phase extraction (SPE) cartridge. It was observed that IAC column was able to separately capture Sudan I, II, III and IV with maximum capacity of 295, 156, 184 and 173ng, respectively. The extraction conditions including loading, washing and eluting solutions were carefully optimized. Under optimal conditions, the extraction recoveries of the IAC column for Sudan I-IV at two different spiked concentrations were within 95.3-106.9%. After 50 times repeated usage, 64% of the maximum capacity was still remained. Six food samples randomly collected from local supermarket without spiking Sudan dyes were extracted with IAC column and detected by high performance liquid chromatography (HPLC). It was found that there was no detectable Sudan II, III and IV in all six food samples, but Sudan I with the content of 2.7-134.5ngg(-1) was detected in three food samples. To further verify the extraction efficiency, other three negative samples were spiked with Sudan I-IV at the concentrations of 20ngg(-1) and 50ngg(-1), which were then extracted with IAC column. The extraction recoveries and relative standard deviation (RSD) were 68.6-96.0% and 4.8-15.2%, respectively, demonstrating the feasibility of the prepared IAC column for Sudan dyes extraction. 相似文献
7.
8.
9.
定义了汉语的分段语法,并根据自然语言的分段循环结构,提出了汉语的分段循环分析策略.它的基本思想是确定语言的一组基本范畴,其相应的句法规则段及其之间的优先关系,对于每一个句法规则段,分别依次采用改进的Kilbury算法、它的优点在于分析过程中的项目集比较小,而且避免了无用分析树的产生,从而大大提高了分析效率. 相似文献
10.
In this paper, we study an inexact version of the alternating direction method of multipliers (ADMM) for solving two-block separable linearly constrained convex optimization problems. Specifically, the two subproblems in the classic ADMM are allowed to be solved inexactly by certain relative error criteria, in the sense that only two parameters are needed to control the inexactness. Related convergence analysis are established under the assumption that the solution set to the KKT system of the problem is not empty. Numerical results on solving a class of sparse signal recovery problems are also provided to demonstrate the efficiency of the proposed algorithm. 相似文献