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121.
The adsorption isotherms of H2S in selected adsorbents were determined at 298 K, at relative pressures up to about 0.005, aiming the use of these materials
in the removal of that pollutant from the museums atmosphere. The Dubinin-Astakhov equation adjusts very well the experimental
results, although one cannot interpret the pre-exponential factor w0 as the limiting adsorbed amount. The parameter E, related with the adsorption energy, and the parameter n, that can be associated with the surface heterogeneity of the adsorbents, are correlated and the first is also correlated
with the adsorbed amounts. It was not found any expectable relationship between the adsorbed amounts and textural parameters
of the adsorbents such as the specific surface area or the microporous volume. This points out that the adsorption of H2S is highly specific. In general, 13X and Y sodium zeolites seem to be the most effective adsorbents, but at lowest tested
pressures, near the concentrations found at museums, a pillared clay prepared from a Wyoming montmorillonite seems to be more
efficient. 相似文献
122.
S. Francis Amevor Hans-Ulrich Hund Albrecht Salzer 《Journal of organometallic chemistry》1996,520(1-2):79-84
A series of heterodimetallic complexes of general formula (C5R5)M(μ-CO)3RuC5Me5 (M = Cr, Mo, W; R = Me, Et) has been prepared in good yields by the reaction of [C5R5M(CO)3]− with [C5Me5Ru(CH3CN)3]+. (C5Me4Et)W(μ-CO)3Ru(C5Me5) was characterized by a crystal structure determination. The W---Ru bond length of 2.41 Å is consistent with the formulation of a metal-metal triple bond, while the unsymmetrical bonding mode of the three bridging carbonyl groups reflects the inherent non-equivalence of the two different C5R5M-units. Using [CpRu(CH3CN)3]+ or [CpRu(CO)2(CH3CN)]+ as the cationic precursor leads to the formation of dimetallic species (C5R5)M(CO)5RuC5H5 with both bridging and terminal carbonyl groups. 相似文献
123.
Thermal investigations of two novel coordination compounds, potential precursor of copper sulfides, namely [Cu2(S2O3)2(NH3)4]·5H2O and Na2[Cu4(S2O3)5(NH3)8]·2H2O were performed either in solid state (static air atmosphere), as well as in reaction medium. During both decompositions,
Cu2+ reduction occurs. In solid state decomposition, a mixture containing sulfides and sulfates is observed. In the reaction medium,
CuSy compounds with sulfur content y (0.66<y<1) dependent on thiosulfate concentration are obtained.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
124.
研究了无水硫化钠与对二氯苯(以N-甲基吡咯烷酮为溶剂)合成聚苯硫醚反应的宏观动力学,该反应是一个小分子缩合串联自缩聚的过程,通过测定不同反应聚合体系中氯化钠的徨成率和硫化内的转化率,建立了该反应的宏观动力学方程:1/(1-PNaCl+PNa2s)=C0Kt+1;并计算得到220、250℃的表观反应速率为4.5×10^-4和3.0×10^-3kg/(mol.s),表观活化能为134kJ/mol。 相似文献
125.
E. N. Deryagina E. N. Sukhomazova E. P. Levanova 《Chemistry of Heterocyclic Compounds》2002,38(1):40-45
The effect of methanol and ethanol on the route of the gas-phase reaction of 2-chlorothiophene with hydrogen sulfide, leading to 2-thiophenethiol and to bis(2-thienyl) sulfide, has been investigated. It was found that methanol significantly enhances this reaction and increases its selectivity for the thiol at higher temperatures than without the initiator. The optimal conditions were achieved at 570°C in the presence of 10 mole % of methanol when the conversion of the 2-chlorothiophene in the reaction with hydrogen sulfide reaches 98% and the yield of the thiophenethiol (43%) exceeds that of the bis(2-thienyl)sulfide (31%). In the absence of methanol the 2-thiophenethiol is formed only at 510-540°C in just 17% yield, the basic reaction product being the indicated sulfide (52% yield); the conversion of the 2-chlorothiophene does not exceed 54%. 相似文献
126.
O. LeynaudA. Lafond Y. MoëloP. Palvadeau A. Meerschaut 《Journal of solid state chemistry》2002,168(1):41-51
Crystal structures of two new misfit compounds, [SrGd0.5S1.5]1.16NbS2 and [Sr(Fe,Nb)0.5S1.5]1.13NbS2, were determined through the composite approach, i.e., by refining each subpart (Q, H-parts, and the common part) of these composite materials, separately. The Q-part is a three-atom-thick layer, with the NaCl-type structure, where external SrS planes enclose the inner GdS or (Fe,Nb)S plane; the structural difference between these two compounds lies in the central layer within the Q-part: Gd and S atoms are in special positions (octahedral coordination), while Fe and S atoms are statistically distributed on split (×4) positions (tetrahedral coordination) around a central unique site (=special position occupied by Nb). The H-part is a sandwich of sulfur planes enclosing the inner Nb plane as observed for the structure of the binary compound NbS2 itself. The Sr-Gd derivative shows a paramagnetic behavior in the whole studied temperature range (2-300 K). On the other hand, antiferromagnetic interactions occur in the Sr-Fe derivative; the complex magnetic behavior of this compound is related to the statistical distribution of Fe atoms which leads to frustration of the magnetic interactions. At room temperature, experimental values obtained from Mössbauer spectrum correspond to Fe3+ in tetrahedral sulfur environment: isomer shift δ=0.32 mm s−1, and quadrupole splitting ΔE=0.48 mm s−1. 相似文献
127.
Manfred Schreiner Peter Ettmayer Richard Kieffer 《Monatshefte für Chemie / Chemical Monthly》1982,113(8-9):869-876
Molybdenum-tungsten-carbonitrides can be prepared by reacting prealloyed powders of Mo and W with carbon in the presence of nitrogen or ammonia. Single phase carbonitrides (Mo, W) (C, N) with the WC-type structure can be obtained. The nitrogen content of these carbonitrides increases with increasing molybdenum content. Flowing ammonia has a decarburizing effect, which has to be counterbalanced by an addition of a carbonaceous gas such as methane. Nitrogen instead of ammonia is equally effective and gives carbonitrides which have a nitrogen content only insignificantly lower than the carbonitrides obtained in flowing ammonia. The lattice parameters of the carbonitrides are found to be slightly smaller than the lattice parameters of the corresponding carbides. 相似文献
128.
O. A. Kholdeeva R. I. Maksimovskaya G. M. Maksimov K. I. Zamaraev 《Reaction Kinetics and Catalysis Letters》1998,63(1):95-102
Alkylammonium salts of Ti(IV)-substituted heteropolytungstate, PW11TiO
10
5−
, catalyze the oxidation of methyl phenyl sulfide with hydrogen peroxide. The yield of the corresponding sulfoxide and sulfone
is practically quantitative. A31P NMR study confirms the formation and reactivity of the PW11O39TiO
2
5−
peroxo complex in organic media. 相似文献
129.
ZnS胶体溶液中某些无机盐光化学过程中产生的阴离子自由基的ESR研究 总被引:4,自引:0,他引:4
本文用自旋捕捉与ESR技术相结合的方法研究了ZnS胶体溶液中某些无机盐光化学过程中产生的无机阴离子自由基,并对自由基产生的机理进行了讨论 相似文献
130.
Photocatalytic reactions occurring at semiconductor particles/solution interfaces can be applied to organic syntheses. In this review article, examples of photocatalytic syntheses of cyclic amino acids by suspended semiconductor particles, e.g., titanium(IV) oxide or cadmium(II) sulfide are introduced and interpreted. Different from the photocatalytic decomposition of pollutants under aerobic conditions, selective conversion of organic compounds can be driven by the photocatalytic reactions under deaerated conditions. 相似文献