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151.
Polysaccharides, oligosaccharides, and their derivatives, particularly of amylose, cellulose, chitosan, and β-cyclodextrin, are well-known chiral selectors (CSs) of chiral stationary phases (CSPs) in chromatography, because they can separate a wide range of enantiomers. Typically, such CSPs are prepared by physically coating, or chemically immobilizing the polysaccharide and β-cyclodextrin derivatives onto inert silica gel carriers as chromatographic support. Over the past few years, new chiral selectors have been introduced, and progressive methods to prepare CSPs have been exploited. Also, chiral recognition mechanisms, which play a crucial role in the investigation of chiral separations, have been better elucidated. Further insights into the broad functional performance of commercially available chiral column materials and/or the respective newly developed chiral phase materials on enantiomeric separation (ES) have been gained. This review summarizes the recent developments in CSs, CSP preparation, chiral recognition mechanisms, and enantiomeric separation methods, based on polysaccharides and β-cyclodextrins as CSs, with a focus on the years 2019–2020 of this rapidly developing field. 相似文献
152.
Bi-functional reactive dyes have been used for reducing the fibrillation of lyocell fibres. The sole influence of CI Reactive
Black 5 dye on the fibrillation tendency of lyocell single jersey knitted fabrics was investigated by dyeing with different
concentrations (35 g/L for medium shade and 70 g/L for dark shade), dyeing without dyestuff and by decolouration process after
each dyeing. The fibrillation tendency of lyocell fibres was accessed by means of fibre wet abrasion resistance and fibrillation
number. Nitrogen content was used as indication of the amount of reactive dye in fabrics during dyeing and decolouration processes.
The correlation between fibre fibrillation tendency and colour values of fabrics was found. Due to the fibrillation reduction,
pilling formation in dyed lyocell fabrics was improved. As colour values can estimate the dye fixation and reduction in fabrics,
reactive dye can be used as a visible marker for crosslinking effect on lyocell fabrics. 相似文献
153.
Lam T. Bui Hussein A. Abbass Daryl Essam 《Computational Optimization and Applications》2009,42(1):105-139
When solving real-world optimization problems, evolutionary algorithms often require a large number of fitness evaluations
in order to converge to the global optima. Attempts have been made to find techniques to reduce the number of fitness function
evaluations. We propose a novel framework in the context of multi-objective optimization where fitness evaluations are distributed
by creating a limited number of adaptive spheres spanning the search space. These spheres move towards the global Pareto front
as components of a swarm optimization system. We call this process localization. The contribution of the paper is a general
framework for distributed evolutionary multi-objective optimization, in which the individuals in each sphere can be controlled
by any existing evolutionary multi-objective optimization algorithm in the literature. 相似文献
154.
Chunlei Wang Michael J. Skibic Richard E. Higgs Ian A. Watson Hai Bui Jibo Wang Jose M. Cintron 《Journal of chromatography. A》2009,1216(25):5030-5038
155.
Trong Nghia Ngo Cong Thin Vo Nguyen Kim Tuyen Pham Nhat Minh Phan Trong Dat Bui Quoc Luan Ngo 《Natural product research》2019,33(2):174-179
One new cycloartane triterpenoid, named markhacanasin C (1), together with three known triterpenoids, oleanolic acid (2), ursolic acid (3) and 6β,19α-dihydroxyursolic acid (4) were isolated by various chromatographic methods from the most cytotoxic fraction of the ethyl acetate extract of Markhamia stipulata var. canaense V.S. Dang leaves. Among them, 4 was reported for the first time from the genus Markhamia, while 2 and 3 were found for the first time from this species. Their structures were elucidated by IR, UV, HR-ESI-MS and NMR experiments. The cytotoxicity of isolated compounds (3 and 4) against three human cancer cell lines (HeLa, HepG2, and MCF-7) were evaluated. At the concentration of 100 μg/mL, 3 exhibited significant cytotoxic activity (86.36 ± 3.69%). 相似文献
156.
Microchimica Acta - A dual-pore covalent organic framework (COF) that contains micropores and mesopores was prepared from 2,4,6-triphenoxy-1,3,5-triazine (TPT). A building block is used in which... 相似文献
157.
Failure of structures and their components is one of major problems in engineering. Studies on mechanical behavior of functionally graded (FG) microplates with defects or cracks by effective numerical methods are rarely reported in literature. In this paper, an effective numerical model is derived based on extended isogeometric analysis (XIGA) for assessment of vibration and buckling of FG microplates with cracks. Based on the modified couple stress theory, the non-classical theory of Reissner–Mindlin plate is extended to capture microstructure, and thus, the size effect. In such theory, possessing C1-continuity is straightforward with the high-order continuity of non-uniform rational B-spline. Due to the use of enrichments in XIGA, crack geometry is independent of the computational mesh. Numerical examples are performed to illustrate the effects of microplate aspect ratio, crack length, internal material length scale parameter, material distribution, and boundary condition on the mechanical responses of cracked FG microplates. The obtained results are compared with reference solutions and that shows that the frequency and buckling loads increases with decreasing the size of FG microplates and crack length. The convergence of the present method is also studied. 相似文献
158.
Thinh Q. Bui P. Bryan Changala Bryce J. Bjork Qi Yu Yimin Wang John F. Stanton 《Molecular physics》2018,116(23-24):3710-3717
ABSTRACTWe use time-resolved direct frequency comb spectroscopy in the mid-infrared to obtain high-resolution rovibrational spectra of products produced from the OD?+?CO reaction. In this work, we present spectral analyses for isotopologues of the transient DOCO radicals from this reaction in the OD stretch region. The analyses were performed with the aid of two different theoretical approaches based on both perturbation theory and variational calculations used for prediction of rovibrational spectra of polyatomic molecules. We discuss the advantages and challenges of our current approach for studying spectroscopy and dynamics of transient molecules. 相似文献
159.
James W. Favell Kerry L. Wilkinson Ieva Zigg Sarah M. Lyons Renata Ristic Carolyn J. Puglisi Eric Wilkes Randell Taylor Duane Kelly Greg Howell Marianne McKay Lucky Mokwena Tim Plozza Pei Zhang AnhDuyen Bui Ian Porter Orrin Frederick Jasha Karasek Colleen Szeto Bruce S. Pan Steve Tallman Beth Anne McClure Hui Feng Eric Herv Anita Oberholster Wesley F. Zandberg Matthew Noestheden 《Molecules (Basel, Switzerland)》2022,27(15)
Vineyard exposure to wildfire smoke can taint grapes and wine. To understand the impact of this taint, it is imperative that the analytical methods used are accurate and precise. This study compared the variance across nine commercial and research laboratories following quantitative analysis of the same set of smoke-tainted wines. In parallel, correlations between the interlaboratory consensus values for smoke-taint markers and sensory analyses of the same smoke-tainted wines were evaluated. For free guaiacol, the mean accuracy was 94 ± 11% in model wine, while the free cresols and 4-methylguaiacol showed a negative bias and/or decreased precision relative to guaiacol. Similar trends were observed in smoke-tainted wines, with the cresols and glycosidically bound markers demonstrating high variance. Collectively, the interlaboratory results show that data from a single laboratory can be used quantitatively to understand smoke-taint. Results from different laboratories, however, should not be directly compared due to the high variance between study participants. Correlations between consensus compositional data and sensory evaluations suggest the risk of perceivable smoke-taint can be predicted from free cresol concentrations, overcoming limitations associated with the occurrence of some volatile phenols, guaiacol in particular, as natural constituents of some grape cultivars and of the oak used for barrel maturation. 相似文献
160.
Thach V. Bui Isao Echizen Minoru Kuribayashi Tetsuya Kojima Thuc D. Nguyen 《Entropy (Basel, Switzerland)》2022,24(11)
The main goal of group testing is to identify a small number of specific items among a large population of items. In this paper, we consider specific items as positives and inhibitors and non-specific items as negatives. In particular, we consider a novel model called group testing with blocks of positives and inhibitors. A test on a subset of items is positive if the subset contains at least one positive and does not contain any inhibitors, and it is negative otherwise. In this model, the input items are linearly ordered, and the positives and inhibitors are subsets of small blocks (at unknown locations) of consecutive items over that order. We also consider two specific instantiations of this model. The first instantiation is that model that contains a single block of consecutive items consisting of exactly known numbers of positives and inhibitors. The second instantiation is the model that contains a single block of consecutive items containing known numbers of positives and inhibitors. Our contribution is to propose efficient encoding and decoding schemes such that the numbers of tests used to identify only positives or both positives and inhibitors are less than the ones in the state-of-the-art schemes. Moreover, the decoding times mostly scale to the numbers of tests that are significantly smaller than the state-of-the-art ones, which scale to both the number of tests and the number of items. 相似文献