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91.
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93.
砂金矿中二氧化硅和金的含量较高,本文用传统的火试金重量法与AAS湿法相结合来测定砂金矿中的金含量,用以得到较为精确的结果。本文用科学的配料方法,调节好熔渣的硅酸度,得到品质更好的熔渣与铅扣。再通过二次补正收集分散在熔渣中的金,之后进行三次补正收集灰皿中残留的金含量,然后用原子吸收光谱—AAS湿法测定三次补正得到的金银合粒与分金液中金的含量,从而得到更精确的结果。此方法操作简便、适用性广、精密度与准确度较高。通过加标测试此方法金的回收率在99.2%~100.3% 之间,金的相对标准偏差(RSD)在0.24%~0.6%之间。 相似文献
94.
不完备信息系统中目前有多种扩充,如基于容差关系的扩充、基于相似关系的扩充等等,但是这些扩充都各自存在局限性。针对这些局限性,引入相对分类错误率的概念,提出了一种基于限制容差关系下的集对变精度粗糙集模型。这就将经典的粗糙集模型和限制容差关系下的集对粗糙集模型进行了推广。然后,讨论了该模型上、下近似算子的一些性质。最后,通过一个具体例子,说明了该模型在不完备信息系统中处理模糊和不确定性知识是可行、有效的。 相似文献
95.
Capillary isoelectric focusing (CIEF) is an important tool for the quality assurance of biotechnologically maintained drugs and for proteome analysis. The critical performance parameters of this technique are the precisions of isoelectric point (pI) values and peak areas. Compared to capillary zone electrophoresis (CZE), where precise results can be obtained (e.g., 0.5% relative standard deviation (RSD) for peak areas, n = 60), only few data are available for CIEF experiments. So far, reproducible data of pI values (RSD = 0.5%) have been acquired, but peak areas show inferior results (about 3-15% RSD). Nonstable capillary coatings and protein adsorption have been discussed as possible reasons. Recent work of Righetti et al. [25, 27] has proven that the use of coated capillaries can reduce the adsorption of proteins by 50% but cannot prevent it. In our CIEF experiments irregular and poorly reproducible peak patterns have been observed. In a long-time experiment of 106 repeated runs, an overall RSD of 10% was obtained for peak areas, RSD of 2% only in series of about 10 consecutive replicates. Especially at higher concentrations the reproducibility deteriorates. This seems to be the result of a self-amplifying process, induced by adsorbed protein molecules, leading to further agglomerations. CZE control experiments in linear polyacrylamide (LPA)-coated capillaries proved a strong pH dependency of these effects within a small range. Compared to bare fused-silica surfaces, adsorption effects are reduced but not inhibited. An enhancement of reproducibility in CIEF experiments can be achieved only by controlling the interactions of proteins and capillary walls. 相似文献
96.
The estimation of the measurement uncertainty of analytical assays based on the LGC/VAM protocol from validation data is fully revisited and discussed in the light of the study of precision, trueness and robustness. 相似文献
97.
阐述了测量方法确认的方法、指标以及方法确认的6种技术手段;介绍了方法确认技术的9种指标以及指标的获得和评价;指出方法确认技术的重点应放在识别和消除显著影响方面。 相似文献
98.
Summary A study has been performed to obtain insight into the relative importance of critical factors affecting the repeatability of hydrodynamic injections in CE. Precision was measured for repeated analysis of a test mixture containing two acidic compounds.The use of an internal standard was clearly shown to improve precision especially when peak area precision was poor. It is suggested that precision is maximised by employing a combination of a constant temperature, an appropriate electrolyte system, an internal standard, long injection times, and high sample concentrations. Other factors are discussed, but are classified as having only a minor impact. 相似文献
99.
Summary The precision of integration over noisy instrumental output for quantitative analysis is studied. A probability theory is
developed to predict the relative standard deviation (RSD) of integration results over an integration domain from one-point
integration (peak height measurement) to entire area integration in HPLC. Common integration modes of horizontal zero line
and oblique zero line are taken into account, but no peak overlap is assumed. The question of the analytical superiority of
peak height measurement or integration for quantitation is answered. In the HPLC apparatus used, the minimum RSD of measurements
is found in the integration domain of ca. ±0.5 σ for analytes [peaks are approximated by the Gaussian signal of width, σ (standard
deviation)]. The RSD of integration measurements is also shown to depend on the stochastic properties of background noise
(uncorrelated noise and correlated 1/f type noise). The theoretical conclusion is verified by Monte Carlo simulation and HPLC
experiments for some aromatic compounds.
Second Part of series cited as Ref. [1]. 相似文献
100.
Projahn HD Steeg U Sanders J Vanclay E 《Analytical and bioanalytical chemistry》2004,378(4):1083-1087
Fast sequential flame atomic-absorption spectrometry (FS-FAAS) is able to measure a sequence of analyte wavelengths in one monochromator scan and so achieves or exceeds the analysis speed of sequential ICP–OES. The requirements and implementation of an FS-FAAS instrument are presented in detail. FS-FAAS is a sequential multi element technique which retains the advantages of conventional FAAS, for example ease of use. While the FS-FAAS technique is an ideal tool for routine determination of elements in the mg L–1 concentration range, it is still subject to common sources of error such as transport problems and long-term drift. The reference-element technique can be used to correct for these types of common interference; other advantages include correction of some errors which are induced during sample preparation, and improved analytical accuracy and precision. The reference-element technique when utilizing the FS- FAAS technique is described in detail and benefits of the technique will be demonstrated by comparing performance for selected applications, for example a mineral sample and a scrap wood digest. 相似文献