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21.
Navjeet Kaur Neha Ahlawat Pranshu Bhardwaj Yamini Verma Pooja Grewal Nirmala Kumari Jangid 《合成通讯》2020,50(6):753-795
AbstractOne of the highly emerging and an important aspect of organic chemistry is the metal catalyzed synthesis of heterocycles. The methods used earlier for the synthesis of heterocycles were significant in the organic synthesis and developing cost-effective, improved and facial methods were beneficial to construct the complex architectures. For the both stereoselective and regioselective synthesis of six-membered nitrogen containing heterocycles, cyclic reactions that are Ag-mediated have known to be very efficient. The present review covers the applications of Ag in the formation of six-membered nitrogen containing heterocycles. 相似文献
22.
Ram C. Maurya Dinesh C. Gupta Rajesh Shukla Raj K. Shukla Nalmas Anandam Mannar R. Maurya 《Transition Metal Chemistry》1986,11(12):463-464
Summary A new series of cyano-substituted nitrosylchromium(I) complexes having octahedral stereochemistry around the metal ion, and of general formula, [CrNO(CN)2(L)2(H2O)] (L =o-,m- andp-phenetidines oro-,m-, andp-anisidines) have been isolated in the solid state by interaction of potassium pentacy-anonitrosylchromate(I) monohydrate with the appropriately substituted aniline. The complexes, which have been characterised by elemental analysis, conductance, molecular weight determination, magnetic measurements, e.s.r. and i.r. spectral studies, contain chromium(I) in a low-spin d5-configuration. 相似文献
23.
Infrared photodissociation spectroscopy is reported for mass-selected Ni+ (H2O)n complexes in the O-H stretching region up to cluster sizes of n = 25. These clusters fragment by the loss of one or more intact water molecules, and their excitation spectra show distinct bands in the region of the symmetric and asymmetric stretches of water. The first evidence for hydrogen bonding, indicated by a broad band strongly red-shifted from the free OH region, appears at the cluster size of n = 4. At larger cluster sizes, additional red-shifted structure evolves over a broader wavelength range in the hydrogen-bonding region. In the free OH region, the symmetric stretch gradually diminishes in intensity, while the asymmetric stretch develops into a closely spaced doublet near 3700 cm(-1). The data indicate that essentially all of the water molecules are in a hydrogen-bonded network by the size of n = 10. However, there is no evidence for the formation of clathrate structures seen recently via IR spectroscopy of protonated water clusters. 相似文献
24.
2-Halophenyl ketones 1a-e (1a, o-IC(6)H(4)COCH(3)) undergo carbocyclization with alkyl propiolates (2a, CH(3)(CH(2))(4)C[triple bond]CCO(2)CH(3); 2b, TMSC[triple bond]CCO(2)Et 2c, CH(3)C[triple bond]CCO(2)CH(3); 2d, CH(3)OCH(2)C[triple bond]CCO(2)CH(3); 2e, CH(3)(CH(2))(3)C[triple bond]CCO(2)CH(3); 2f, PhC[triple bond]CCO(2)CH(3); and 2g, (CH(3))(3)C[triple bond]CCO(2)CH(3)) in the presence of Ni(dppe)Br(2) and zinc powder in acetonitrile at 80 degrees C to afford the corresponding indenol derivatives 3a-m with remarkable regioselectivity in good to excellent yields. The nickel-catalyzed carbocyclization reaction was successfully extended to other simple disubstituted alkynes. Thus, the reaction of 2-halophenyl ketones 1a-e with disubstituted alkynes (2h, PhC[triple bond]CPh; 2i, CH(3)C(6)H(4)C[triple bond]CC(6)H(4)CH(3); 2j, CH(3)CH(2)C[triple bond]CCH(2)CH(3); 2k, PhC[triple bond]CCH(3); 2l, TMSC[triple bond]CCH(3); and 2m, PhC[triple bond]C(CH(2))(3)CH(3)) proceeded smoothly to afford the corresponding indenols 4a-t in good to excellent yields. For unsymmetrical alkynes 2k-m, the carbocyclization gave two regioisomers with regioselectivities ranging from 1:2 to 1:12 depending on the substituents on the alkyne and on the aromatic ring of halophenyl ketone. A possible mechanism for this nickel-catalyzed carbocyclization reaction is also proposed. 相似文献
25.
Dinesh Kumar Ashu Rani D. S. N. Prasad K. S. Gupta 《Reaction Kinetics and Catalysis Letters》1991,43(1):133-141
The kinetics of the oxidation of 2-furancarboxaldehyde by thallic perchlorate at 50°C obeys the rate law
相似文献
26.
27.
Dr. Waqar Rizvi Naxhije Berisha Dr. Christopher Farley Dr. N. V. S. Dinesh K. Bhupathiraju Dr. Chrysafis Andreou Emaad Khwaja German V. Fuentes Dr. Moritz F. Kircher Dr. Ruomei Gao Dr. Charles Michael Drain 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(64):14517-14521
Distortion of nominally planar phthalocyanine macrocycles affects the excited state dynamics in that most of the excited-state energy decays through internal conversion. A click-type annulation reaction on a perfluorophthalocyanine platform appending a seven-membered ring to the β-positions on one or more of the isoindoles distorts the macrocycle and modulates solubility. The distorted derivative enables photoacoustic imaging, photothermal effects, and strong surface-enhanced resonance Raman signals. 相似文献
28.
Anshu Dandia Dinesh Kumar Mahawar Ruchi Sharma Ranveer Singh Badgoti Kuldeep S. Rathore Vijay Parewa 《应用有机金属化学》2019,33(11)
Graphene oxide (GO)‐catalyzed selective synthesis of amides via CSp3–H activation of methylarenes and consequent C–N bond formation with anilines under aqueous medium has been described. Oxygen functionality allied with GO surface played a dual role both as acid catalyst and oxidizing agent to some extent. However, GO has a copious effect on the reaction, shown by a high TOF value with TBHP as co‐oxidant. The decisive role of carboxylic acid functional groups on GO nanosheets in this metal‐free strategy has been confirmed and was monitored by various analytic techniques viz. Fourier transform‐infrared, UV–Vis, Raman and XPS. A plausible mechanism was proposed by control experiments and by the isolation of the intermediate. Over‐oxidation of methylarenes was not detected, and high recyclability of the carbocatalyst with its heterogeneous behavior facilitated the isolation and purification of the desired products. We have further explored the utility of this process for the chemoselective synthesis of benzimidazoles. 相似文献
29.
M. Roy S. Sahu S. K. Barbar S. Jangid 《Journal of Thermal Analysis and Calorimetry》2013,113(2):873-879
Polycrystalline ceramic samples of Bi4V2?xMexO11 (Me = Nb, Zr, Y and Cu and x = 0.0 and 0.02) have been synthesized by standard solid state reaction method using high purity oxides. The formation of the compounds have been analysed by X-ray diffraction method. The dielectric constant, dielectric loss and AC conductivity as a function of frequency and temperature have been measured. The dielectric studies indicate that the material is highly lossy and hence its AC conductivity increases with the increase of temperature. The DC conductivity of material has been measured as a function of temperature from room temperature to 380 °C and its activation energy was calculated using the relation σ = σ 0exp (?E a/kT). The modulated differential scanning calorimetry has been used to investigate the effect of substitution on the heat capacity and heat flow of the compounds. The results are discussed in detail. 相似文献
30.
Ramesh C. Kamboj Dinesh Kumar Rita Arora Surinder Berar Geeta Sharma 《Journal of heterocyclic chemistry》2013,50(Z1):E200-E203
The photo‐irradiation of thienylchromenone resulted in the regioselective cyclization which is exclusively controlled by the nature of solvent used as reaction medium. Compared to nonpolar medium, polar solvent furnished a diverse array of novel angular tetracyclic photoproducts with gem‐dihydro functionality and exocyclic double bonds on the fused pyran ring, which is unprecedented to best of our knowledge. 相似文献
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