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971.
Fumed silica (SiO2)-based composite polymer electrolytes were prepared by means of solution casing technique. Horizontal attenuated total reflectance-Fourier Transform Infrared (HATR-FTIR) study shows the complexation between polymer matrix and SiO2. The highest ionic conductivity of (4.11 ± 0.01) × 10? 3 Scm? 1 is achieved upon inclusion of 8 wt.% of SiO2. Three different regions have been observed in the frequency dependence–ionic conductivity study. The conductivity rises sharply with frequency at low frequency regime. It is followed by a frequency independent plateau region and sharp decrease in the conductivity at high frequency range. The dielectric permittivity (ε') and dielectric loss (ε") are decreased with increasing the frequency. This phenomenon is mainly attributed to the electrode polarization effect. The formation of electrical double layer has been proven in these dielectric permittivity studies. This indicates the non-Debye properties of the nano-composite polymer electrolytes. 相似文献
972.
Attractive bonding interactions between molecules typically have inherent conservation laws which influence the statistical properties of such systems in terms of corresponding sum rules. We have considered lattice water as an example, and we have enunciated the consequences of the sum rule through a general computational procedure called molecular mean field theory. Fluctuations about the mean field are computed and many of the liquid properties have been deduced and compared with Monte Carlo simulation, molecular dynamics, and experimental results. Large correlation lengths are seen to be a consequence of the sum rule in the liquid phase. Long-range Coulomb interactions are shown to have minor effects on our results. 相似文献
973.
M Ramesh B Raju M George K Srinivas V Jayathirtha Rao K Bhanuprakash R Srinivas 《Journal of mass spectrometry : JMS》2012,47(7):860-868
The electrospray ionization collisionally activated dissociation (CAD) mass spectra of protonated 2,4,6-tris(benzylamino)-1,3,5-triazine (1) and 2,4,6-tris(benzyloxy)-1,3,5-triazine (6) show abundant product ion of m/z 181 (C(14) H(13)(+)). The likely structure for C(14) H(13)(+) is α-[2-methylphenyl]benzyl cation, indicating that one of the benzyl groups must migrate to another prior to dissociation of the protonated molecule. The collision energy is high for the 'N' analog (1) but low for the 'O' analog (6) indicating that the fragmentation processes of 1 requires high energy. The other major fragmentations are [M?+?H-toluene](+) and [M?+?H-benzene](+) for compounds 1 and 6, respectively. The protonated 2,4,6-tris(4-methylbenzylamino)-1,3,5-triazine (4) exhibits competitive eliminations of p-xylene and 3,6-dimethylenecyclohexa-1,4-diene. Moreover, protonated 2,4,6-tris(1-phenylethylamino)-1,3,5-triazine (5) dissociates via three successive losses of styrene. Density functional theory (DFT) calculations indicate that an ion/neutral complex (INC) between benzyl cation and the rest of the molecule is unstable, but the protonated molecules of 1 and 6 rearrange to an intermediate by the migration of a benzyl group to the ring 'N'. Subsequent shift of a second benzyl group generates an INC for the protonated molecule of 1 and its product ions can be explained from this intermediate. The shift of a second benzyl group to the ring carbon of the first benzyl group followed by an H-shift from ring carbon to 'O' generates the key intermediate for the formation of the ion of m/z 181 from the protonated molecule of 6. The proposed mechanisms are supported by high resolution mass spectrometry data, deuterium-labeling and CAD experiments combined with DFT calculations. 相似文献
974.
975.
976.
Olivier E. Nonga Darja Lavogina Erki Enkvist Katrin Kestav Apirat Chaikuad Sarah E. Dixon-Clarke Alex N. Bullock Sergei Kopanchuk Taavi Ivan Ramesh Ekambaram Kaido Viht Stefan Knapp Asko Uri 《Molecules (Basel, Switzerland)》2021,26(14)
We performed an X-ray crystallographic study of complexes of protein kinase PIM-1 with three inhibitors comprising an adenosine mimetic moiety, a linker, and a peptide-mimetic (d-Arg)6 fragment. Guided by the structural models, simplified chemical structures with a reduced number of polar groups and chiral centers were designed. The developed inhibitors retained low-nanomolar potency and possessed remarkable selectivity toward the PIM kinases. The new inhibitors were derivatized with biotin or fluorescent dye Cy5 and then applied for the detection of PIM kinases in biochemical solutions and in complex biological samples. The sandwich assay utilizing a PIM-2-selective detection antibody featured a low limit of quantification (44 pg of active recombinant PIM-2). Fluorescent probes were efficiently taken up by U2OS cells and showed a high extent of co-localization with PIM-1 fused with a fluorescent protein. Overall, the developed inhibitors and derivatives represent versatile chemical tools for studying PIM function in cellular systems in normal and disease physiology. 相似文献
977.
Proton spin lattice relaxation time (T1), measured as a function of temperature in the range 375–77 K, shows slope changes at 333, 221 and 111 K, in addition to a first order phase transition at 150K. The observed T1 behaviour and second moment (M2) variation with temperature are explained on the basis of the different possible motions of CH3 and NH3 groups. 相似文献
978.
979.
N. Ch. Ramesh Babu Ch. Srinivasa Rao M. G. Brik G. Naga Raju I. V. Kityk N. Veeraiah 《Applied physics. B, Lasers and optics》2013,110(3):335-344
In this study, we have investigated the principal role of Y2O3 on the emission features of Tm3+ ion and up-conversion phenomenon in Tm3+ and Yb3+ co-doped Li2O–Y2O3–SiO2 glass system. The concentration of Y2O3 is varied from 0 to 5 mol% while that of Yb3+ and Tm3+ is fixed. When the glasses are doped with Tm3+ ions, the intense blue and red emissions were observed, whereas Yb3+ doped glasses exhibited NIR emission at about 980 nm. When the glasses are co-doped with Tm3+ and Yb3+ ions and excited at 900 nm, the blue and red emission lines were observed to be reinforced and strengthened with increase in the concentration of Y2O3. The IR emission band detected at about 1.8 μm due to 3F4 → 3H6 transition of Tm3+ ions is also observed to be strengthened due to co-doping. The reasons for enhancement in the intensity of various emission bands due to co-doping have been identified and discussed with the help of rate equations for various emission transitions. 相似文献
980.
K. Karnakar S. Narayana Murthy K. Ramesh G. Satish Jagadeesh Babu Nanubolu Y.V.D. Nageswar 《Tetrahedron letters》2012,53(23):2897-2903
A simple, efficient, and eco-friendly synthetic protocol has been developed via one pot three-component reaction between aldehyde, amino pyrazole, and 1,3-cyclohexanedione by using recyclable polyethylene glycol (PEG)-400 as a reaction medium. Utilizing this protocol a variety of pyrazolo[3,4-b]quinoline derivatives were synthesized in excellent yields. 相似文献