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991.
992.
993.
We show that the Hausdorff dimension of quasi-circles of polygonal mappings is one.Furthermore,we apply this result to the theory of extremal quasiconformal mappings.Let [μ] be a point in the universal Teichmller space such that the Hausdorff dimension of fμ(Δ) is bigger than one.We show that for every kn∈(0,1) and polygonal differentials ψn,n=1,2,...,the sequence {[kn ψn/|ψn|]} cannot converge to [μ] under the Teichmer metric. 相似文献
994.
995.
996.
A new chitosan imprinting adsorbent using diatomite as core material was prepared by using the surface molecular imprinting
technology with the Pb2+ as imprinted ion. The preparation process conditions of the surface molecular imprinting adsorbent were studied. The adsorbent
was characterized by using Fourier transform infrared (FTIR) spectrum. FTIR spectrum indicated that it was cross-linked by
epichlorohydrin. The new imprinting adsorbent could provide a higher adsorption capacity for Pb2+, which reached 139.6 mg/g increasing 32.3% compared with cross-linking chitosan adsorbent (the initial Pb2+ concentration of 600 mg/L). The adsorption velocity was quick and the equilibration time of the imprinting adsorbent for
Pb2+ was 3 h that shortened about 40% compared with cross-linking chitosan adsorbent. It had a more wide pH range of 5–7 than
that of cross-linking chitosan adsorbent. The new imprinting adsorbent can be reused for up to ten cycles without loss of
adsorption capacity. In the kinetics and isotherm study, the pseudosecond order model and Langmuir model could represent the
adsorption process. 相似文献
997.
Yan Qiao Youguang Ma Yan Huo Peisheng Ma Shuqian Xia 《The Journal of chemical thermodynamics》2010,42(7):852-855
Densities of ionic liquids at different temperature and pressure were collected from 84 references. The collection contains 7381 data points derived from 123 pure ionic liquids and 13 kinds of binary ionic liquids mixtures. In terms of the collected database, a group contribution method based on 51 groups was used to predict the densities of ionic liquids. In group partition, the effect of interaction among several substitutes on the same center was considered. The same structure in different substitutes may have different group values. According to the estimation of pure ionic liquids’ densities, the results show that the average relative error is 0.88% and the standard deviation (S) is 0.0181. Using the set of group values three pure ionic liquids densities were predicted, the average relative error is 0.27% and the S is 0.0048. For ionic liquid mixtures, they are thought considered as idea mixtures, so the group contribution method was used to estimate their densities and the average relative error is 1.22% with S is 0.0607. And the method can also be used to estimate the densities of MClx type ionic liquids which are produced by mixing an ionic liquid with a Cl? anion and a kind of metal chloride. 相似文献
998.
999.
通过实验对不同温度条件下半胱氦酸抑制盐酸对碳钢腐蚀的性能进行评价,并采用分子动力学模拟(Molecular Dynamics Simulation,简称MD)方法,从缓蚀剂膜抑制腐蚀粒子扩散的角度对其缓蚀机理进行深入研究.静态失重实验显示:随温度的升高(25~65℃),半胱氨睃缓蚀剂的缓蚀效率呈逐渐下降趋势,其数值从88.36%降至61.64%.MD模拟发现:随温度升高,半胱氨酸缓蚀剂膜的自由体积逐渐增大,且腐蚀粒子与缓蚀剂膜的相互作用也逐渐减弱,更有利于腐蚀粒子在膜中的主动扩散;同时膜内半胱氨酸分子的自扩散能力也随温度升高而增强,腐蚀粒子在缓蚀剂膜携带下被动迁移的过程也随之加剧.主动扩散和被动迁移两方面的变化表明,腐蚀粒子在缓蚀剂膜中扩散能力随温度升高而增大;也就是说,随温度升高,半胱氨酸缓蚀剂膜对腐蚀粒子的扩散抑制能力逐渐降低,腐蚀粒子更易扩散运移至金属表面,导致半胱氨酸缓蚀剂缓蚀效率的降低. 相似文献
1000.
Dr. Xian‐Kuan Huo Ge Su Prof. Dr. Guo‐Xin Jin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(39):12017-12027
Monophosphine‐o‐carborane has four competitive coordination modes when it coordinates to metal centers. To explore the structural transitions driven by these competitive coordination modes, a series of monophosphine‐o‐carborane Ir,Rh complexes were synthesized and characterized. [Cp*M(Cl)2{1‐(PPh2)‐1,2‐C2B10H11}] (M=Ir ( 1 a ), Rh ( 1 b ); Cp*=η5‐C5Me5), [Cp*Ir(H){7‐(PPh2)‐7,8‐C2B9H11}] ( 2 a ), and [1‐(PPh2)‐3‐(η5‐Cp*)‐3,1,2‐MC2B9H10] (M=Ir ( 3 a ), Rh ( 3 b )) can be all prepared directly by the reaction of 1‐(PPh2)‐1,2‐C2B10H11 with dimeric complexes [(Cp*MCl2)2] (M=Ir, Rh) under different conditions. Compound 3 b was treated with AgOTf (OTf=CF3SO3?) to afford the tetranuclear metallacarborane [Ag2(thf)2(OTf)2{1‐(PPh2)‐3‐(η5‐Cp*)‐3,1,2‐RhC2B9H10}2] ( 4 b ). The arylphosphine group in 3 a and 3 b was functionalized by elemental sulfur (1 equiv) in the presence of Et3N to afford [1‐{(S)PPh2}‐3‐(η5‐Cp*)‐3,1,2‐MC2B9H10] (M=Ir ( 5 a ), Rh ( 5 b )). Additionally, the 1‐(PPh2)‐1,2‐C2B10H11 ligand was functionalized by elemental sulfur (2 equiv) and then treated with [(Cp*IrCl2)2], thus resulting in two 16‐electron complexes [Cp*Ir(7‐{(S)PPh2}‐8‐S‐7,8‐C2B9H9)] ( 6 a ) and [Cp*Ir(7‐{(S)PPh2}‐8‐S‐9‐OCH3‐7,8‐C2B9H9)] ( 7 a ). Compound 6 a further reacted with nBuPPh2, thereby leading to 18‐electron complex [Cp*Ir(nBuPPh2)(7‐{(S)PPh2}‐8‐S‐7,8‐C2B9H10)] ( 8 a ). The influences of other factors on structural transitions or the formation of targeted compounds, including reaction temperature and solvent, were also explored. 相似文献