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1.
Summary The enantiomers of chiral carboxylic acids were separated as their diastereomeric amides with (1R,2R)-(−)-1-(4-nitrophenyl)-2-amino-1,3-propanediol
(“levobase”) and with “dextrobase” (the enantiomer of levobase) by high-performance liquid chromatography using a conventional
C-18 column and various solvent systems containing acetonitrile, methanol, water, and phosphoric acid. 相似文献
2.
R.?T.?Savalia K.?N.?Lad A.?PratapEmail author G.?K.?Dey S.?Banerjee 《Journal of Thermal Analysis and Calorimetry》2004,78(3):745-751
The formation of nano-quasicrystals on isothermal annealing of melt-spun ribbons of Zr69.5Al7.5Ni11Cu12 metallic glass has been investigated using transmission electron microscopy (TEM). The crystallization study of this metallic glass has been carried out using differential scanning calorimetry (DSC) in non-isothermal (linear heating) mode. It exhibits two-stage crystallization where the first stage corresponds to the precipitation of icosohedral nano-quasicrystalline phase. This has been confirmed with the help of TEM investigations. The crystallization parameters like the activation energy (E
c) and frequency factor (k
0) have been derived using the Kissinger peak shift analysis. The activation energies for the first and second crystallization peak are found to be 278 and 295 kJ mol–1, respectively. The frequency factors obtained for the two peaks are respectively 7.16·1019 and 1.42·1020 s–1. E
c, k
0 and the Avrami exponent (n) have also been derived by fitting the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation for the transformed volume fraction (x) to the crystallization data. JMAK results of E
c for the first and second crystallization peak turn out to be 270 and 290 kJ mol–1 respectively. However, k
0 and n are found to be heating rate dependent as reported in similar studies. The values of n for the first crystallization stage ranges between 1.66 and 2.57 indicating diffusion-controlled transformation in agreement with earlier reports. 相似文献
3.
V. V. Aksenova R. M. Nikonova V. L. Lad’yanov V. V. Mukhgalin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(10):1726-1731
The crystal solvates in C60-CCl4 and C70-CCl4 systems obtained by crystallization from CCl4 solution at room temperature were studied by IR Fourier spectroscopy and X-ray diffraction. The C70 · (CCl4) n crystal solvate was obtained and studied for the first time; its hexagonal crystal lattice has unit cell parameters a = 10.658 ± 0.001 Å and c = 10.811 ± 0.002 Å. The temperature ranges of its destruction were determined. 相似文献
4.
Some new biologically potent coumarin derivatives 7a–f, 8a–f, and 9a–f bearing modified pyridine moieties (indeno[1,2-b]pyridine, 4-azaphenanthrene and benzofuro [3,2-b]pyridine) at the sixth position were designed and synthesized. All the synthesized compounds were assayed for their antimicrobial efficiency against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Salmonella typhi, Candida albicans, and Aspergillus niger. Most of the compounds showed appreciable antimicrobial activity against the tested strains. Compounds 8b, 8c, 9b, 9d, and 9f emerged as most proficient members of the series. The antitubercular activity for all the synthesized compounds was performed against Mycobacterium tuberculosis H37Rv. Compounds 8f, 9b, and 9f exhibited promising antitubercular activity. Consequently, synthesized derivatives were found to be worthy of further investigation. 相似文献
5.
V. V. Aksenova R. M. Nikonova V. I. Lad’yanov N. B. Tamm E. V. Skokan B. E. Pushkarev 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(10):1749-1755
The oxidation of C60 and C70 fullerites and C60/C70 mixture is accompanied by the decomposition of the carbon frameworks of the molecules at annealing temperatures of 250 and 445°C. Fourier-IR and HPLC studies show that the oxidation/decomposition of C70 molecules is more active than that of C60. The stages of fullerite interaction with oxygen while heating in air were determined. 相似文献
6.
Molecular Diversity - The oxidation of benzylic alcohol to corresponding aldehyde and ketone using N-chlorosuccinimide (NCS)–N,N-dimethylformamide (DMF) has been described. This method gives... 相似文献
7.
V. I. Lad’yanov S. G. Men’shikova A. L. Bel’tyukov B. B. Maslov 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(8):1176-1178
We investigate the temperature and time dependences of viscosity of Al99Y1, Al97Y3, Al95Y5 melts in the range from liquidus to 1200°C. By metallographic, XRD, and differential thermal analyses, we study how the time
of isothermal holding of melts influences the structure of ingots during hardening. 相似文献
8.
Rhodium Enalcarbenoids: Direct Synthesis of Indoles by Rhodium(II)‐Catalyzed [4+2] Benzannulation of Pyrroles 下载免费PDF全文
Sudam Ganpat Dawande Vinaykumar Kanchupalli Jagadeesh Kalepu Haribabu Chennamsetti Bapurao Sudam Lad Dr. Sreenivas Katukojvala 《Angewandte Chemie (International ed. in English)》2014,53(16):4076-4080
Disclosed herein is the design of an unprecedented electrophilic rhodium enalcarbenoid which results from rhodium(II)‐catalyzed decomposition of a new class of enaldiazo compounds. The synthetic utility of these enalcarbenoids has been successfully demonstrated in the first transition‐metal‐catalyzed [4+2] benzannulation of pyrroles, thus leading to substituted indoles. The new benzannulation has been applied to the efficient synthesis of the natural product leiocarpone as well as a potent adipocyte fatty‐acid binding protein inhibitor. 相似文献
9.
T. Braun L. Ladányi M. Maróthy I. Osgyáni 《Journal of Radioanalytical and Nuclear Chemistry》1969,2(3-4):263-273
The principle of displacement substoichiometry and the possibilities of its practical use have been outlined. The substoichiometric
separation of lead, arsenic, and zinc can be carried out by applying diethyldithiocarbamate complexes and solvent extraction. 相似文献
10.
Jan Finjord Aksel Hiorth Unn H. a Lad Svein M. Skjæveland 《Transport in Porous Media》2007,69(1):33-53
We consider analytical and numerical solution of NMR relaxation under the condition of surface relaxation in an equilateral
triangular geometry. We present an analytical expression for the Green’s function in this geometry. We calculate the transverse
magnetic relaxation without magnetic gradients present, single-phase, both analytically and numerically. There is a very good
match between the analytical and numerical results. We also show that the magnetic signal from an equilateral triangular geometry
is qualitatively different from the known solution: plate, cylinder, and sphere, in the case of a nonuniform initial magnetization.
Nonuniform magnetization close to the sharp corners makes the magnetic signal very fast multiexponential. This type of initial
configuration fits qualitatively with the experimental results by Song (Phys. Rev. Lett. 85, 3878 (2000)), Song et al. (Nature
406, 178 (2000)), Song (Mag. Reson. Imag. 19, 417 (2001)) and Lisitza and Song (Phys. Rev. B
65, 172406 (2002)). It should also be noted that the solution presented here can be used to describe absorption of a chemical
substance in an equilateral triangular geometry (for a stationary fluid). 相似文献