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911.
Corzana F Busto JH Marcelo F de Luis MG Asensio JL Martín-Santamaría S Sáenz Y Torres C Jiménez-Barbero J Avenoza A Peregrina JM 《Chemical communications (Cambridge, England)》2011,47(18):5319-5321
A novel Tn antigen mimic, in which the natural underlying amino acid has been replaced by the non-natural α-methylserine analogue, is reported. This derivative exhibits a similar affinity for a natural lectin as for the natural Tn and retains the bioactive conformation observed in the Tn-containing glycopeptides with anti-MUC1 antibodies. 相似文献
912.
Jiménez-Aquino A Flegeau EF Schneider U Kobayashi S 《Chemical communications (Cambridge, England)》2011,47(33):9456-9458
We developed catalytic intermolecular C(sp(3))-C(sp(3)) cross-couplings between various allyl alcohols and allyl boronates, which proceeded smoothly in the presence of nickel(0) under mild conditions to form 1,5-dienes with excellent linear- and γ-selectivity; the use of boronates proved to be crucial in terms of reactivity. 相似文献
913.
Fu W Kiggans J Overbury SH Schwartz V Liang C 《Chemical communications (Cambridge, England)》2011,47(18):5265-5267
Microwave induced rapid decomposition of nitromethane at low temperature exfoliates the graphene sheets from the FeCl(3) and CH(3)NO(2) co-intercalated graphite compound without creating many defects and functional groups. This approach provides a scalable method for high-quality graphene materials via low-temperature exfoliation of graphite under mild chemical conditions. 相似文献
914.
The tetranortriterpene cipadonoid B was efficiently constructed from synthetic azedaralide in a one-pot cascade, via the underutilised ketal-Claisen rearrangement. 相似文献
915.
The fluoride affinities of fluorinated alanes, AlHmF3?m (m = 1–3) were measured using energy-resolved collision-induced dissociation of fluorinated aluminate anions. The AlHmF4?m? anions were formed by reaction of dimethylethylamine-alane with fluoride ion and F2. From the measured bond dissociation energies, the fluoride affinities of fluorinated alanes are determined to be 93.2 ± 3.1, 97.5 ± 4.0, and 108.6 ± 3.7 kcal/mol for m = 3, 2, and 1, respectively. The fluoride affinities are in good agreement with the theoretical calculations at the CCSD(T)/CBS and B3LYP/6-31 + G* levels of theory. The increased Lewis acidity of more fluorinated alanes is attributed to increased positive charge density on the aluminum. 相似文献
916.
Liu Zhaolin Tay Siok Wei Hong Liang Lee Jim Yang 《Journal of Solid State Electrochemistry》2011,15(1):205-209
Olivine-type LiFePO4 composite materials for cathode material of the lithium-ion batteries were synthesized by using a sol-gel method and were
coated by a chemical deposition of silver particles. As-obtained LiFePO4/C-Ag (2.1 wt.%) composites were characterized by transmission electron microscopy (TEM), powder X-ray diffraction (XRD),
conductivity measurements, cyclic voltammetry, as well as galvanostatic measurements. The results revealed that the discharge
capacity of the LiFePO4/C-Ag electrode is 136.6 mAh/g, which is 7.6% higher than that of uncoated LiFePO4/C electrode (126.9 mAh/g). The LiFePO4/C coated by silver nanoparticles enhances the electrode conductivity and specific capacity at high discharge rates. The improved
capacity at high discharge rates may be attributed to increased electrode conductivity and the synergistic effect on electron
and Li+ transport after silver incorporation. 相似文献
917.
918.
919.
Williams MR True AB Izmaylov AF French TA Schroeck K Schmuttenmaer CA 《Physical chemistry chemical physics : PCCP》2011,13(24):11719-11730
Experimental and computational THz (or far-infrared) spectra of polycrystalline valine samples are reported. The experimental spectra have been measured using THz time-domain spectroscopy. Spectra of the pure enantiomers, both D and L, as well as the dl racemate have been taken at room temperature and low temperature (78 K). The spectra of the pure D and L enantiomers are essentially identical, and they are markedly different from the DL racemate. In addition, a temperature-dependent study of L-valine was undertaken in which the absorption maxima were found to red shift as a function of increasing temperature. The vibrational absorption spectra (frequencies and intensities) were calculated using the harmonic approximation with the Perdew-Burke-Ernzerhof (PBE) functional, localized atomic orbital basis sets, and periodic boundary conditions. The calculated and experimental spectra are in good qualitative agreement. A general method of quantifying the degree to which a calculated mode is intermolecular versus intramolecular is demonstrated, with the intermolecular motions further separated into translational versus rotational/librational motion. This allows straightforward comparison of spectra calculated using different basis sets or other constraints. 相似文献
920.
Antiñolo M Jiménez E Albaladejo J 《Physical chemistry chemical physics : PCCP》2011,13(35):15936-15946
Ultraviolet (UV) absorption cross sections of CF(3)CH(2)CHO were determined between 230 and 350 nm by gas-phase UV spectroscopy. The forbidden n → π* transition was characterized as a function of temperature (269-323 K). In addition, the photochemical degradation of CF(3)CH(2)CHO was investigated at 308 nm. The possible photolysis channels are: CF(3)CH(2) + HCO , CF(3)CH(3) + CO , and CF(3)CH(2)CO + H . Photolysis quantum yields of CF(3)CH(2)CHO at 308 nm, Φ(λ=308nm), were measured as a function of pressure (25-760 Torr of synthetic air). The pressure dependence of Φ(λ=308nm) can be expressed as the following Stern-Volmer equation: 1/Φ(λ=308nm) = (4.65 ± 0.56) + (1.51 ± 0.04) × 10(-18) [M] ([M] in molecule cm(-3)). Using the absorption cross sections and the photolysis quantum yields reported here, the photolysis rate coefficient of this fluorinated aldehyde throughout the troposphere was estimated. This calculation shows that tropospheric photolysis of CF(3)CH(2)CHO is competitive with the removal initiated by OH radicals at low altitudes, but it can be the major degradation route at higher altitudes. Photodegradation products (CO, HC(O)OH, CF(3)CHO, CF(3)CH(2)OH, and F(2)CO) were identified and also quantified by Fourier transform infrared spectroscopy. CF(3)CH(2)C(O)OH was identified as an end-product as a result of the chemistry involving CF(3)CH(2)CO radicals formed in the OH + CF(3)CH(2)CHO reaction. In the presence of an OH-scavenger (cyclohexane), CF(3)CH(2)C(O)OH was not detected, indicating that channel (R1c) is negligible. Based on a proposed mechanism, our results provide strong evidences of the significant participation of the radical-forming channel (R1a). 相似文献