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121.
Summary A CE method has been validated for the analysis of batches of lactose used as a pharmaceutical raw material. This method was
shown to be selective for lactose and was found to be quantitative. The separation was achieved due to on-capillary chelation
of the lactose with borate ion. The resulting complex was detected at 195nm. An internal standard is employed to improve injection
precision and detector linearity. A system peak occurred in the separation and was systematically investigated to show that
it was not sample related. The method was validated and successfully submitted to regulatory authorities and is now in routine
use in a number of our quality control laboratories. 相似文献
122.
Adriaan M. H. van der Veen Thomas P. J. Linsinger Andree Lamberty Jean Pauwels 《Accreditation and quality assurance》2001,6(6):257-263
To serve as a measurement standard, a (certified) reference material must be stable. For this purpose, the material should
undergo stability testing after it has been prepared. This paper looks at the statistical aspects of stability testing. Essentially,
these studies can be described with analysis of variance statistics, including variant regression analysis. The latter is
used in practice for both trend analysis and for the development of expressions for extrapolations. Extrapolation of stability
data is briefly touched upon, as far as the combined standard uncertainty of the reference material is concerned. There are
different options to validate the extrapolations made from initial stability studies, and some of them might influence the
uncertainty of the reference material and/or the shelf-life. The latter is the more commonly observed consequence of what
is called ’stability monitoring’.
Received: 6 October 2000 Accepted: 4 December 2000 相似文献
123.
The Level of Repair Analysis – LORA – is an analytic methodology aimed at determining: (i) the optimal location of facilities that compose a maintenance structure; (ii) the quantity of required resources in each facility; and (iii) the best repair policies, i.e., rules that determine if a given component should be discarded or repaired, and where those actions should take place. This work presents a mixed-integer programming model for LORA that is more comprehensive than others in the literature, being suitable to many practical situations. The model was applied to 15 substantial real world problems, and considering distinct maintenance policies to some of them, resulted in 22 different solutions, all of which could be achieved by a commercial Mixed-Integer Programming (MIP) solver in reasonable times. 相似文献
124.
In this paper, we show the results of an experimental study about the most important algorithms proposed to solve the Maximum
Flow problem. The appropriate statistical analysis not only allows us to justify comparisons between the different procedures
but also to obtain classifications of their practical efficiency. Furthermore, an empirical experiment allows us to identify
the influence of several parameters that are not included in a theoretical study. 相似文献
125.
126.
不精确数据的相似度及其在聚类分析中的应用 总被引:4,自引:0,他引:4
基本包含度理论,提出不精确数据的一种相似度,并讨论基于此相似度的不精确数据的聚类方法。 相似文献
127.
Abstract We develop a modular landscape model for the mountain pine beetle (Dendroctonus ponderosae Hopkins) infestation of a stage‐structured forest of lodgepole pine (Pinus contorta Douglas). Beetle attack dynamics are modeled using response functions and beetle movement using dispersal kernels. This modeling technique yields four model candidates. These models allow discrimination between four broad possibilities at the landscape scale: whether or not beetles are subject to an Allee effect at the landscape scale and whether or not host selection is random or directed. We fit the models with aerial damage survey data to the Sawtooth National Recreation Area using estimating functions, which allows for more rapid and complete parameter determination. We then introduce a novel model selection procedure based on facial recognition technology to compliment traditional nonspatial selection metrics. Together with these we are able to select a best model and draw inferences regarding the behavior of the beetle in outbreak conditions. 相似文献
128.
For the purpose of exploring and modeling the relationships between a dataset Y and several datasets () measured on the same individuals, multiblock Partial Least Squares is a regression technique which is widely used, particularly in process monitoring, chemometrics and sensometrics. In the same vein, a new multiblock method, called multiblock Redundancy Analysis, is proposed. It is introduced by maximizing a criterion that reflects the objectives to be addressed. The solution of this maximization problem is directly derived from the eigenanalysis of a matrix. In addition, this method is related to other multiblock methods. Multiblock modeling methods provide to the user a large spectrum of interpretation indices for the investigation of the relationships among variables and among datasets. They are related to the criterion to maximize and therefore directly derived from the maximization problem under consideration. The interest of multiblock Redundancy Analysis and the associated interpretation tools are illustrated using a dataset in the field of veterinary epidemiology. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
129.
Species of the genus Cystoseira are particularly hard to discriminate, due to the complexity of their morphology, which can be influenced by their phenological state and ecological parameters. Our study emphasized on the relevance of two kinds of analytical tools, (1) LC/ESI-MSn and (2) 1H HR-MAS NMR, also called in vivo NMR, to identify Cystoseira specimens at the specific level and discuss their taxonomy. For these analyses, samples were collected at several locations in Brittany (France), where Cystoseira baccata, C. foeniculacea, C. humilis, C. nodicaulis and C. tamariscifolia were previously reported. To validate our chemical procedure, the sequence of the ITS2 has been obtained for each species to investigate their phylogenetic relationships at a molecular level. Our study highlighted the consistency of the two physico-chemical methods, compared to “classical” molecular approach, in studying taxonomy within the genus Cystoseira. Especially, LC/ESI-MSn and phylogenetic analyses converged into the discrimination of two taxonomical groups among the 5 species. The occurrence of some specific signals in the 1H HR-MAS NMR spectra and/or some characteristic chemical compounds during LC/ESI-MSn analysis could be regarded as discriminating factors. LC/ESI-MSn and 1H HR-MAS NMR turned out to be two relevant and innovative techniques to discriminate taxonomically this complex genus. 相似文献
130.
L. Santonja-Blasco 《Polymer Degradation and Stability》2010,95(11):2185-2191
An accelerated soil burial test has been performed on a commercial polylactide (PLA) for simulating non-controlled disposal. Degradation in soil promotes physical and chemical changes in polylactide properties, which can be characterized by Thermal Analysis techniques. Physical changes occurred in polylactide due to the degradation in soil were evaluated by correlating their calorimetric and viscoelastic properties. It is highly remarkable that each calorimetric scan offers specific and enlightening information. Degradation in soil affects the polylactide chains reorganization. A multimodal melting behavior is observed for buried PLA, degradation in soil also promotes the enlarging the lamellar thickness distribution of the population with bigger average size. Morphological changes due to degradation in soil lead to an increase in the free volume of the polylactide chains in the amorphous phase that highly affected the bulk properties. Thermal Analysis techniques provide reliable indicators of the degradation stage of polylactide induced by degradation in soil, as corroborated by molecular weight analysis. 相似文献