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41.
A new anisotropic potential is fitted to {\it ab initio} data. The close-coupling
approach is utilized to calculate state-to-state rotational excitation
partial wave cross sections for elastic and inelastic collisions of He atom
with HBr molecule based on the fitted potential. The calculation is
performed separately at the incident energies: 75, 100 and 200~meV.The
tendency of the elastic and inelastic rotational excitation partial wave
cross sections varying with total angular quantum number $J$ is obtained. 相似文献
42.
《Surface science》1986,171(1):111-134
The mechanism of ethanol decomposition on the Ni(111) surface has been investigated between 155 and 500 K. The sequence of bond scission steps which occur as ethanol undergoes dissociative reactions on this surface has been deduced using deuterium and 13C isotopic labels. Bond activation occurs in the order (1) OH, (2) CH2 (methylene CH), (3) CC, (4) CH3 (methyl CH). The products observed are CH3CHO(g), CH4(g), CO(g), H2(g) and surface carbon, C(a). The latter species exhibits a carbidic AES lineshape in the temperature range 450 to 670 K, at which temperature it dissolves into the Ni bulk. Acetaldehyde, CH3CHO, and methane, CH4, desorb with the same threshold temperature (260–265 K), and the formation of both of these products is controlled by scission of the methylene CH bond (CH2 group). The CH3 group is cleaved from the intermediate surface CH3CHO species to form CH3(ads). H2 exhibits a broad, doublet desorption peak from 300 to 450 K. The carbonoxygen bond in ethanol remains intact and CO ultimately desorbs in a single desorption limited process (Tp = 430 K). A small fraction of CO(a) species undergo exchange with the carbidic surface carbon in a minor process observed above 440 K. 相似文献
43.
采用正交试验法,对板蓝根靛玉红超临界CO2萃取工艺进行优化。选用萃取温度、萃取压力、萃取时间作为正交试验的3个因素,每个因素选3个水平,以提取物中靛玉红的含量来确定最佳提取条件,并且在最佳条件下确定所加夹带剂的最佳剂量。结果表明最佳工艺为:萃取温度45℃、萃取压力35MPa、萃取时间3h,夹带剂为75%的乙醇200mL。最佳工艺条件下提取靛玉红的得率为4.95μg/g,为传统提取方法的1.6倍。 相似文献
44.
大蓟多糖提取分离及含量测定 总被引:1,自引:1,他引:1
用水提-醇沉法从大蓟中提取多糖,脱脂、去蛋白,经冷冻干燥后得到粗多糖。通过苯酚-硫酸法测定糖的含量,粗多糖得率为6.5%。再采用DEAE-纤维素离子交换柱层析进一步分离纯化,得到5个次级组分DJ1,DJ2,DJ3,DJ4和DJ5。其中得率最高的是DJ2组分,为8.06‰。 相似文献
45.
本文构建评价我国农村现代化的指标体系,运用因子分析与聚类分析的方法,对我国31个地区的农村现代化状况进行实证分析,从中勾画我国农村现代化的基本特征,并相应地探讨这些基本特征形成的原因。文章最后结合实证分析的结论对我国农村现代化的建设提出几点建议。 相似文献
46.
《Chemical physics letters》1985,113(1):56-62
We have used ESDIAD (electron stimulated desorption ion angular distributions) to characterize the structure and bonding of O2 on Ag(110). The data indicate that both atomic oxygen (Tads > 300 K) and molecular oxygen (Tads ⋍ 80 K) are bonded in configurations which cause ion desorption in directions along [001] azimuths. Possible structures are discussed which are at variance with existing models of the oxygen-Ag(110) system. 相似文献
47.
ZHOU Hong-Bo CHEN You-Cun ② 《结构化学》2008,27(6):697-700
The title compound [BrBzPy][TCNQ] (BrBzPy^+=1-(4-bromobenzyl)pyridinium cation, TCNQ = 7,7,8,8-tetracyanoquinodimethanide anion) was synthesized by the reaction of [BrBzPy]Br and LiTCNQ in ethanol solution and its structure was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c with a = 14.067(3), b = 7.3089(14), c = 23.796(4)A, β = 122.011(9)°, V= 2074.6(7)A^3, Z = 4, C24H15BrN5, Mr = 453.32, Dc = 1.451 g/cm^3,μ = 2.002 mm^-1, S = 1.047, F(000) = 916, R = 0.0398 and wR = 0.0921. The most prominent structural features are the completely segregated stacking columns of the TCNQ- anions and [BrBzPy]^+ cations. In a TCNQ column, the centroid-to-centroid distances of the neighboring anions of TCNQ are 3.2693 and 4.9464 A, respectively. 相似文献
48.
Structural Chemistry - The core-shell morphologies of (PdPt)coreAgshell and (PdPt)coreAushell up to 147 atoms are investigated. The structural optimization of M–Pd–Pt (M = Ag or Au) is... 相似文献
49.
本文讨论了广义Z4线性Calderbank-McGuire码的对偶的迹表示及2-adic表示, 同时给出了其最小Lee权估计. 相似文献
50.
In this paper, we estimate the size of k-uniform hypergraph with diameter d, and give its minimum and maximum. 相似文献