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101.
Summary. In this study, the stoichiometric protonation constants, logKOH and logKNH, of sixteen substituted N-benzylidene-2-hydroxyanilines have been determined potentiometrically in ethanol-water mixtures of varying composition (10–80%
ethanol by volume) at 25.0±0.1°C. The values of the constants, logK, were submitted to factor analysis in order to obtain the number of factors which affect the variation of the whole data
sets of protonation constants and, afterwards, to target factor analysis to identify these factors. The influence of solvatochromic
parameters in the interactions between Schiff bases derivatives and the solvent studied was identified and quantified. Kamlet and Taft general equations allow calculation of the logK values of Schiff bases studied in any ethanol-water mixtures up to 80% (v/v) and thus provide the knowledge of the acid-base behaviour in these solvent media. Further, the quasi-lattice quasi-chemical
(QLQC) theory of preferential solvation has been applied to quantify the preferential solvation by water of electrolytes in
ethanol-water mixtures. 相似文献
102.
The use of sodium hexametaphosphate in the spectrofluorometric determination of trace amounts of cerium(III) ions is described. Sodium hexametaphosphate acts as a specific reagent for enhancing the fluorescence intensity of cerium(III) in aqueous solutions. The apparent excitation and fluorescence wavelength used are 304 and 344 nm, respectively. Maximum fluorescence intensity is obtained by irradiating Ce(III) dissolved in 5.346 g/l sodium hexametaphosphate solution at room temperature. The fluorescence varies linearly with the concentration of cerium(III) in the range of 0.001–60 g/ml. The coefficient of variation for 45 g/ml Ce(III) in 5.346 g/l sodium hexametaphosphate solution is 1. The quenching effects of other lanthanides and some inorganic anions are given. This technique permits a direct and rapid determination of cerium(III) in rare earth mixtures and cerium concentrates. 相似文献
103.
104.
Graph Theoretic and Spectral Analysis of Enron Email Data 总被引:1,自引:0,他引:1
Anurat?ChapanondEmail author Mukkai?S.?Krishnamoorthy Bülent?Yener 《Computational & Mathematical Organization Theory》2005,11(3):265-281
Analysis of social networks to identify communities and model their evolution has been an active area of recent research.
This paper analyzes the Enron email data set to discover structures within the organization. The analysis is based on constructing
an email graph and studying its properties with both graph theoretical and spectral analysis techniques. The graph theoretical
analysis includes the computation of several graph metrics such as degree distribution, average distance ratio, clustering
coefficient and compactness over the email graph. The spectral analysis shows that the email adjacency matrix has a rank-2
approximation. It is shown that preprocessing of data has significant impact on the results, thus a standard form is needed
for establishing a benchmark data.
Anurat Chapanond is currently a Ph.D. student in Computer Science, RPI. Anurat graduated B. Eng. degree in Computer Engineering from Chiangmai
University (Thailand) in 1997, M. S. in Computer Science from Columbia University in 2002. His research interest is in web
data mining analyses and algorithms.
M.S. Krishnamoorthy received the B.E. degree (with honors) from Madras University in 1969, the M. Tech degree in Electrical Engineering from
the Indian Institute of Technology, Kanpur, in 1971, and the Ph. D. degree in Computer Science, also from the Indian Institute
of Technology, in 1976.
From 1976 to 1979, he was an Assistant Professor of Computer Science at the Indian Institute of Technology, Kanpur. From 1979
to 1985, he was an Assistant Professor of Computer Science at Rensselaer Polytechnic Institute, Troy, NY, and since, 1985,
he has been an Associate Professor of Computer Science at Rensselaer. Dr. Krishnamoorthy's research interests are in the design
and analysis of combinatorial and algebraic algorithms, visualization algorithms and programming environments.
Bulent Yener is an Associate Professor in the Department of Computer Science and Co-Director of Pervasive Computing and Networking Center
at Rensselaer Polytechnic Institute in Troy, New York. He is also a member of Griffiss Institute of Information Assurance.
Dr. Yener received MS. and Ph.D. degrees in Computer Science, both from Columbia University, in 1987 and 1994, respectively.
Before joining to RPI, he was a Member of Technical Staff at the Bell Laboratories in Murray Hill, New Jersey.
His current research interests include bioinformatics, medical informtatics, routing problems in wireless networks, security
and information assurance, intelligence and security informatics. He has served on the Technical Program Committee of leading
IEEE conferences and workshops. Currently He is an associate editor of ACM/Kluwer Winet journal and the IEEE Network Magazine.
Dr. Yener is a Senior Member of the IEEE Computer Society. 相似文献
105.
Burlov A. S. Borodkina I. G. Kuznetsova L. I. Uraev A. I. Makarova N. I. Vasil'chenko I. S. Borodkin G. S. Altun O. Feiizoglu A. Garnovskii A. D. 《Russian Journal of General Chemistry》2004,74(5):772-775
Chelate complexes of 2-{[4-(3,5-diphenyl-4,5-dihydropyrazol-1-yl)benzylidene]amino}benzenethiol (LH) of the ML2 composition and with an M2N2S2 five-membered coordination unit were obtained. The syntheses were carried out by chemical (from LH and metal acetates) and electrochemical (from LH and zerovalent metals) methods in methanol. The chelate compounds were assigned cis-planar (M = Ni) and tetrahedral (M = Co, Zn, Cd) configurations. 相似文献
106.
Safi Altunöz Hüseyin Çelik Mehmet Cankurtaran 《Central European Journal of Physics》2008,6(3):479-490
The mobility of electrons in vertical transport in GaAs/Ga1−y
Al
y
As barrier structures was investigated using geometric magnetoresistance measurements in the dark. The samples studied had
Ga1−y
Al
y
As (0 ≤ y ≤ 0:26) linearly graded barriers between the n+-GaAs contacts and the Ga0:74Al0:26As central barrier, which contain N
w
(=0, 2, 4, 7 and 10) n-doped GaAs quantum wells. The mobility was determined as functions of (i) temperature (80–290 K) at
low applied voltage (0.01–0.1 V) and (ii) applied voltage (0.005–1.6 V) at selected temperatures in the range 3.5–290 K. The
experimental results for the temperature dependence of low-field mobility suggest that space-charge scattering is dominant
in the samples with N
w
=0 and 2, whereas ionized impurity scattering is dominant in the samples with N
w
=4, 7 and 10. The effect of polar optical phonon scattering on the mobility becomes significant in all barrier structures
at temperatures above about 200 K. The difference between the measured mobility and the calculated total mobility in the samples
with N
w
=4, 7 and 10, observed above 200 K, is attributed to the reflection of electrons from well-barrier interfaces in the quantum
wells and interface roughness scattering. The rapid decrease of mobility with applied voltage at high voltages is explained
by intervalley scattering of hot electrons.
相似文献
107.
Ishak Altun 《Journal of Fixed Point Theory and Applications》2011,9(1):125-134
We present some common fixed point theorems for multivalued maps satisfying an implicit relation on complete metric spaces.
Also a homotopy result is given for multivalued maps. 相似文献
108.
B. Sevim A. Bayraktar A. C. Altunışık S. Adanur M. Akköse 《Experimental Mechanics》2011,51(5):787-791
This study determines the dynamic characteristics of a prototype arch dam-reservoir-foundation system using Operational Modal
Analysis method. Achievement of this purpose involved construction of a prototype arch dam-reservoir-foundation system under
laboratory conditions. Ambient vibration tests on the arch dam model identified its natural frequencies, mode shapes, and
damping ratios. Natural excitations such as small impact loads vibrated to arch dam. Sensitivity accelerometers which were
placed on the dam’s crest collected signals in measurements. Measurements were recorded for empty and full reservoirs. Operational
Modal Analysis software processed signals which were collected from the ambient vibration tests. Enhanced Frequency Domain
Decomposition technique estimated dynamic characteristics of the dam. Results showed that there was an approximate 20–25%
difference between natural frequencies related to empty and full reservoirs. 相似文献
109.
Jose A. Goncalves Neto Ersan Altun Mohamed Elazzazi Georgeta D. Vaidean Matthew Chaney Richard C. Semelka 《Magnetic resonance imaging》2010
Purpose
To compare the extent of enhancement of abdominal organs as shown on subphases of hepatic arterial phase quantitatively between 1.5- and 3.0-T MRI among patients with various abdominal conditions.Materials and Methods
A total of 126 patients, of whom 68 were women (age range, 3–82 years; mean age, 48 years) and 58 were men (age range, 6–73 years; mean age, 50 years), were included in the study. Of 126 patients, 98 were scanned at 1.5 T and 28 were scanned at 3.0 T. The presence of one of three predefined subphases of hepatic arterial phase was determined on early post-gadolinium sequence in each patient by two reviewers in consensus. Extent of enhancement of the kidney, pancreas, spleen and liver on these subphases was determined quantitatively by measuring the signal intensities. Mann Whitney–Wilcoxon test was used to compare the contrast enhancement of organs on each subphase between 1.5- and 3.0-T MRI.Results
The kidney, spleen, pancreas and liver demonstrated 1.79- to 2.45-, 1.65- to 1.97-, 1.66- to 1.8- and 1.1- to 2.02-fold higher enhancement on the subphases of hepatic arterial phase at 3.0 T compared to 1.5 T, respectively. The differences in contrast enhancement were significant for the kidney, pancreas and spleen on all subphases between 1.5 and 3.0 T.Conclusion
The relative enhancement of the kidney, spleen and pancreas is consistently and significantly higher at 3.0 T than at 1.5 T in matched subphases of hepatic arterial enhancement. 相似文献110.
Yildiz Uygun Cebeci Sule Ceylan Sengul Alpay Karaoglu Muhammed Altun 《Journal of heterocyclic chemistry》2023,60(1):47-62
1,2,4-Triazole-fluoroquinolone and 1,2,4-triazole–conazole hybrids are designed, synthesized, and investigated in vitro against a variety of common diseases. The structure of the newly synthesized compounds are characterized from spectral data (IR, 1H NMR, 13C NMR, and LC–MS). The antibacterial activity against both Gram-positive and Gram-negative bacteria is shown to be enhanced by many of the produced compounds. Also, some of the products are found to have strong antiproliferative effects aganist HeLa cervical cancer cells, whilst demonstrating cytotoxic effects toward normal cells. 相似文献