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71.
72.
The inequalities su At su Am ≥ su Ap su Aq and At+ su Am≥ su Ap+ su Aq are studied and generalized. Here su A denotes the sum of elements of the square matrix A. 相似文献
73.
Jorma Tarhio 《BIT Numerical Mathematics》1990,30(3):437-449
Evaluation of inherited attributes is a problem in conjunction with LR parsing, because the derivation tree is incomplete during parsing. An evaluation scheme for inherited attributes is presented based on a restricted grammar class, uncle-attributed grammars. A transformation to the uncle-attributed form is described for L-attributed grammars. 相似文献
74.
A comparative TG and DTG study of the preparation and thermal stability of selected rare earth oxycarbonates, (REO)2CO3 (RE = La and Gd), shows that the ease of formation as well as the stability of these compounds decreases strongly with increasing atomic number of the host cation. According to X-ray powder diffraction analyses, the RE oxycarbonates obtained as decomposition products of acetate and carbonate hydrates belong to the tetragonal IA-type. UV- and dye laser-excited luminescence studies of Eu3+-doped (LaO)2CO3 and (GdO)2CO3 reveal the presence of two different sites for the host cation. One of the sites resembles closely that prevailing in the tetragonal RE oxysalts, i.e. oxyhalides, oxysulphates, oxymolybdates and oxynitrates. A crystal field analysis carried out on the 7F1 and 7F2 level schemes according to a C2v site symmetry confirms this hypothesis. 相似文献
75.
A fluid queue receiving its input from the output of a precedingM/M/1 queue is considered. The input can be characterized as a Markov modulated rate process and the well known spectral decomposition technique can be applied. The novel features in this system relate to the nature of the spectrum, which is shown to be composed of a continuous part and one or two discrete points depending on whether the load of the fluid queue is less or greater than the output to input rate ratio. Explicit expressions of the generalized eigenvectors are given in terms of Chebyshev polynomials of the second kind, and the resolution of unity is determined. The solution for the buffer content distribution is obtained as a simple integral expression. Numerical examples are given. 相似文献
76.
It is demonstrated that in many situations the sum of elements and the trace of a matrix behave similarly. 相似文献
77.
Identification of the hydrolysis products of AlCl3.6H2O by electrospray ionization mass spectrometry
Sarpola A Hietapelto V Jalonen J Jokela J Laitinen RS 《Journal of mass spectrometry : JMS》2004,39(4):423-430
The hydrolysis reactions of AlCl3 in 0.1 M aqueous solutions at pH 3.27-4.20 were monitored by electrospray ionization time-of-flight mass spectrometry (ESI-ToF MS) as a function of time. The cationic and anionic ESI mass spectra of aluminum(III) solutions gave strong evidence of the presence of a variety of monomeric and polymeric complexes. Competition between the OH- and Cl- ligands within the same aluminum core was observed. The influence of the sample cone voltage on the product distribution was also explored. The optimum sample cone voltage for the cationic spectra was 70 V. For the anionic spectra no optimum sample cone voltage was found and the appearance of the anionic spectra was strongly dependent on the sample cone voltage within the whole range explored. 相似文献
78.
Kumpulainen AJ Persson CM Eriksson JC Tyrode EC Johnson CM 《Langmuir : the ACS journal of surfaces and colloids》2005,21(1):305-315
To examine the transition from the gaseous to the liquid-expanded monolayer state, surface tension data were recorded for n-decyl beta-d-glucopyranoside (Glu) and n-decyl beta-d-maltopyranoside (Mal) solutions at low concentrations and at different temperatures. Comparisons were also made with n-decyl beta-d-thiomaltopyranoside (S-Mal) solutions at room temperature. The transitions observed occur at very low concentrations and surface pressures, about 0.5% of the critical micelle concentration (cmc) and between 0.8 and 1 mN/m for Glu and Mal at 22 degrees C. For S-Mal the transition is recorded for a concentration of 0.5% of the cmc as well, but the surface pressure is lower, about 0.4 mN/m. The gradual change in molecular area about the transition is from about 500 to 200 A(2) and 400 to 150 A(2) for Mal and Glu, respectively, and from about 800 to 250 A(2) for S-Mal. The comparatively large molecular areas after the transitions are incompatible with the notion that a coherent hydrocarbon film would cover the entire surface already at this stage. Standard surface thermodynamics was applied to elucidate the nature of these transitions in combination with two model concepts: The formation of an infinite network of surfactant molecules and, second, the formation of surface micelles. Hard-disk simulation results were employed to quantify the additional surface pressure after the transition attributed to the formation of surface micelles. In conclusion the formation of surface micelles is plausible as the hard-disk model is capable of accounting for the additional surface pressure increase with acceptable accuracy. Further, vibrational sum frequency spectroscopy was used to investigate the transition for Mal. Using the distinct feature of the non-hydrogen-bonded OH ("free OH") at 3700 cm(-)(1) for probing the surface water state, it could be determined that the surface holds a sizable fraction of unperturbed surface water even after the transition from the Henry range. The decrease in the free OH signal was found to correlate with the increase in surface density of surface micelles. 相似文献
79.
Jorma T. Kumpulainen Helena Hyvärinen Margareta Hägg Sirkka Plaami Raija Tahvonen 《Analytical and bioanalytical chemistry》1995,352(1-2):102-106
As part of the analytical assurance system of the FAO European Cooperative Research Network on Trace Elements programme an ARC/CL-coded carrot flakes powder (CFP) candidate reference material (RM) has been prepared from a lot of commercial carrot flakes. The candidate RM has been homogenized using a Robot Coupe blender fitted with titanium blades, carefully homogenized in large teflon/polypropylene containers, bottled in 1000 numbered polyethylene containers (20 g samples) and tested for homogeneity. Interlaboratory comparison studies for 9 essential elements, cadmium and total dietary fiber (TDF) based on the AOAC-method resulted in the characterization of the contents of those compounds in the above material. After exclusion of outliers, mean values from at least nine different laboratories based altogether on three independent analytical principles have been used to calculate the recommended concentration ranges for mineral elements. Testing of homogeneity and stability for β-carotene over a period of one year has been additionally carried out. The mean water content in the material amounted to 4.97% and remained stable over a one-year period. Homogeneity of the RM was within 3.0% for almost all included mineral elements as tested for a sample size of 0.5 g. The 95% confidence limits for the mean values of the established recommended concentrations of mineral elements in the present ARC/CL Carrot Powder candidate RM fell within 5% for all the other elements and TDF except for Fe (6.3%) and B (5.7%). The stability of β-carotene in the present candidate RM stored in darkness over a one-year period at room temperature was within 6.3%. 相似文献
80.
Sari Kiviniemi Maija Nissinen Tanja Kolli Jorma Jalonen Kari Rissanen Jouni Pursiainen 《Journal of inclusion phenomena and macrocyclic chemistry》2001,40(1-2):153-159
Crown ether complexes of six-membered N-heteroaromatic cations and the closely related bicyclic purinium cation (6) have been studied by 1H NMR, mass spectrometric and crystallographic methods. The stability constants for the complexes were determined by 1H NMR titration in acetonitrile solution and the complexation stoichiometry by 1H NMR and ESI mass spectrometric methods. Altogether six crystal structures of complexes were determined to study the complexation in the solid state. Hydrogen bonding was observed to be the most important interaction for the complexation both in solution and in the solid state but – interactions also contribute to it. All crystal structures of the DB18C6 complexes with six-membered N-heteroaromatic cations, except for 4-hydroxypyridinium, are isomorphous to previously studied five-membered N-heteroaromatic cations and pyridinium complexes. Such a close resemblance is not observed in B18C6 and 18C6 complexes or DB18C6purinium (6). 相似文献