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61.
Rapid,clean, and mild O-acetylation of alcohols and carbohydrates in an ionic liquid 总被引:2,自引:0,他引:2
Forsyth SA MacFarlane DR Thomson RJ von Itzstein M 《Chemical communications (Cambridge, England)》2002,(7):714-715
Archetypal O-acetylation reactions of alcohols and carbohydrates proceed rapidly in high yield under mild conditions in a dicyanamide based ionic liquid, that is not only an effective solvent but also an active base catalyst. 相似文献
62.
P. MORLIÉRE M. BAZIN L. DUBERTRET R. SANTUS T. SA E. MELO G. HÜPPE J. HAIGLE P. FORLOT A. BERNARD 《Photochemistry and photobiology》1991,53(1):13-19
5-Geranoxypsoralen, commonly called bergamottin, a major furocoumarin contained in bergamot oil, is reported in vitro as a highly photoreactive psoralen. In ethanol, it exhibits quite a high triplet state quantum yield (approximately 0.37). The triplet state is involved in subsequent photochemistry which depends on the initial concentration and on the presence of oxygen. In contrast to most psoralens, absorption and fluorescence data suggest that 5-geranoxypsoralen does not interact with DNA in the dark. No UVA-induced interstrand cross-links in DNA were shown. 相似文献
63.
We investigate the thermoelectric properties of GaN with p-and n-type doping by the first principles calculation and the semi-classical Boltzmann theory. We find that the power factors (S2σof p-type GaN (-3500 W/mK2) is about twice that of the n-type (-1750 W/mK2), which indicates the thermoelectric properties of p-type GaN would be better. Thermal conductivity of GaN crystal decreases rapidly as the temperature increases, but it is still too large for thermoelectric applications. The figure of merit (ZT) estimated at 1500 K is 0.134 for p-type GaN crystal and 0.062 for the n-type. 相似文献
64.
Robert G.K. Donald Stephen Skwish R. Allyn Forsyth Jennifer W. Anderson Tanya Zhong Colleen Burns Suzy Lee Xin Meng Lynn LoCastro Lisa Wang Jarantow Jesus Martin Sang Ho Lee Ian Taylor David Robbins Cheryl Malone Liangsu Wang Carlos S. Zamudio Philip J. Youngman John W. Phillips 《Chemistry & biology》2009,16(8):826-836
65.
QCD PERTURBATION THEORY AND NUCLEI (1) THE ENERGY SHIFTS OF HADRENS AND HADRONS MASS DIFFERENCE MASS DIFFERENCE 下载免费PDF全文
QCD perturbation theory for confined quarks and gluons (inhadrons) is discussed.Based on the equivalent potential for the quark-gluon interaction derived, the energyshifts of hadrons and hadron mass difference in MIT bag (cavity) model and correcpond-ing approximation of the w. f. with Gassian form are calculated. 相似文献
66.
67.
In the framework of density functional theory (DFT), the electronic excitations and nonlinear optical (NLO) properties of six binuclear transition metal cluster anions with the formula of [Ch2M-(μ-Ch)2-M'CN]^2- (M = Mo, W; Ch = S, Se; M' = Cu, Ag) have been systemically investigated at both cases of gas phase and DMF solution. The obtained electronic absorption spectra reveal that the element replacements of metals M and ligands Ch have significant influence on the absorptions, especially on the low-lying ones. In addition, the transitions of μ-Ch→M are dominant for the low-lying excitations, whereas the transitions of M'→M as well as Ch→M are mainly responsible for the higher excitations. The calculated molecular first and second hyperpolarizabilities present the remarkable element substitution and solvent effects. The analyses show that the transitions involving μ-Ch→M charge transfer make the critical contributions to the first hyperpolarizability t, and that the charge transfers from the moieties of MCh4 to M'CN as well as those of μ-Ch→M and M'→M are responsible for the second hyperpolarizability y. Moreover, the introduction of solvent leads to the results that the transitions within the moieties of MCh4 and M'CN make larger contributions to the hyperpolarizability, especially to γ. 相似文献
68.
LU ZhongDao SA BenHao Masanori Matsuda Junichi Nagata Atsushi Nakamura Osamu Miyamura 《中国物理C(英文版)》2000,24(8):743-747
The Λ multiplicity and Λ/p ratio are studied by hadron transportation-string fragmentation model in relativistic heavy ion collisions. Firstly, the dependence of Λ multiplicity and Λ/p ratio on the system size and the collision centrality is studied. It shows that the Λ and p multiplicities go up as the increase of system size and the increase of collision centrality. However, their ratio keeps almost a constant. The effect of Λ annihilation cross section to Λ multiplicity and Λ/p ratio is also studied. It is found that this effect is weak: Λ multiplicity and Λ/p ratio have a little amount of increase by the decrease of Λ annihilation cross section. Even the cross section is down to zero, Λ/p ratio is only 1.2 in 200A GeV AuAu head on collision. The Λ/p ratio is obtained to be 0.28 in pp collision, lying in the range of experimental data:0.2—0.3. It is also obtained that the ratio in AA collisions is 3—5 times of that in pp collision. 相似文献
69.
Estelle Mossou Susana C. M. Teixeira Edward P. Mitchell Sax A. Mason Lihi Adler‐Abramovich Ehud Gazit V. Trevor Forsyth 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(3):326-331
The title zwitterion (2S)‐2‐azaniumyl‐1‐hydroxy‐3‐phenylpropan‐1‐olate, C9H11NO2, also known as L‐phenylalanine, was characterized using synchrotron X‐rays. It crystallized in the monoclinic space group P21 with four molecules in the asymmetric unit. The 0.62 Å resolution structure is assumed to be closely related to the fibrillar form of phenylalanine, as observed by electron microscopy and electron diffraction. The structure exists in a zwitterionic form in which π–π stacking and hydrogen‐bonding interactions are believed to form the basis of the self‐assembling properties. 相似文献
70.
Alison J. Davenport Maria Forsyth Melanie M. Britton 《Electrochemistry communications》2010,12(1):44-47
Compositional and structural changes within an electrolyte solution above an electrochemically active metal surface have been visualised using magnetic resonance imaging (MRI) for the first time. In these proof-of-concept experiments, zinc metal was galvanically corroded in a saturated lithium chloride solution. Magnetic resonance relaxation maps were taken during the corrosion process and spatial variations in both T1 and T2 relaxation times were observed to change with time. These changes were attributed to changes in the speciation of zinc ions in the electrolyte. 相似文献