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901.
Anion can be identified by pyromellitic imide-azacyclophane which is one of the host compounds.This article investigated the interaction between the host and organic pollution compounds.The host and other eight compounds were optimized by DFT(density functional theory) B3LYP/6-31G level and the energy of compounds was corrected using Boys-Bemardi method.On the basis of B3LYP/6-31G optimized geometries,the RDG function and sign(λ2(r))ρ(r) function values of space points were calculated,and color RDG isosurface map was drawn.3He chemical shift was calculated by the B3LYP/6-31G method.The results showed that the eight organic pollution molecules with the host one shaped stable configurations by hydrogen bonds,respectively.The stabilization energy of complexes 4 and 7 showed repulsion(steric effects) of cyclophane cage observably affecting the stability of the complexes.The location,intensity and the type of interaction in complex 1 were analyzed through color-filled RDG isosurface map.Aromaticity calculations showed that the weak interaction reduced the transverse induction ring current in the host rings,and deteriorated the aromaticity of compounds. 相似文献
902.
Prof. Dr. Holger Braunschweig Alexander Damme Dr. Daniela Gamon Hauke Kelch Dr. Ivo Krummenacher Dr. Thomas Kupfer Dr. Krzysztof Radacki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(27):8430-8436
We describe the synthesis of base‐free bisborole [Cym?(BC4Ph4)2]—Cym?=(OC)3Mn(η5‐C5H3)—and its transformation into two fully characterized Lewis acid–base adducts with pyridine bases of the type 4‐R? NC5H4 (R=tBu, NMe2). The results of electrochemical, as well as NMR and UV/Vis spectroscopic studies on [Cym?(BC4Ph4)2] and the related monoborole derivative [Cym(BC4Ph4)]—Cym=(OC)3Mn(η5‐C5H4)—provided conclusive evidence for 1) the enhanced Lewis acidity of the two boron centers that result from conjugation of two borole fragments, and 2) the fact that Mn? B bonding interactions between the Lewis acidic borole moieties and the Mn center are considerably less pronounced for bisborole [Cym?(BC4Ph4)2]. In addition, the reduction chemistry of [Cym?(BC4Ph4)2] has been studied in detail, both electrochemically and chemically. Accordingly, chemical reduction of [Cym?(BC4Ph4)2] with magnesium anthracene afforded the corresponding tetraanion, which features a rare Mg? OC bonding mode in the solid state. 相似文献
903.
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905.
选用6-311++G(3df,2p)基组,在二级微扰的理论下,对四角锥形结构化合物BeB4X4(X=H,F,Cl),HBB4H4与BB4H4+的分子振动频率,及原子间的相互作用进行了计算,作用能的计算使用了CCSD(T)方法。结果显示HBB4H4与BB4H4+是违反韦德规则的另两个特例,它们表现稳定的原因与芳香性有关。 相似文献
906.
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908.
Tingting Cao Yipei Ma Xiuhua Yan Jiagao Cheng Youhua Luo Liming He Weiliang Zhu 《中国化学》2009,27(10):1914-1918
To investigate whether free cyclooctatetraene dianion (COT2?) is aromatic, quantum chemistry methods were used to optimize its structure. Based on the optimized structures, the natural population analysis (NPA) charge, bond order, delocalization energy, nucleus‐independent chemical shift (NICS), and harmonic oscillator model of aromaticity (HOMA) values were computed by DFT‐B3LYP method with basis set 6‐311++G**, which shows that COT2? is not aromatic as it is not planar and has different bond lengths and bond orders, smallest delocalization energy and positive NICS values. To further confirm the finding, the changes of NICS and energy against ring distortion angle were scanned. The COT2? has positive NICS values all along the angle from 180° to 120° while other aromatic systems always have negative values. The energy scanning suggests that COT2? should have the weakest capability to maintain its planar structure. All the calculations strongly indicate that COT2? is not aromatic. This study also suggests that NICS scan might be a good approach to judge aromaticity. 相似文献
909.
Dr. Gang Zhang Dr. Frank Rominger Prof. Dr. Michael Mastalerz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(9):3084-3093
On the basis of a threefold borylated truxene, which is accessible in high yields by iridium‐catalyzed borylation under CH‐activation, fused π‐extended truxenes have been synthesized by a two‐step method of first Suzuki–Miyaura cross‐coupling reaction and subsequent condensation reaction. The mild condensation method tolerates the presence of a variety of functional groups, such as nitro, fluoro, or carboxyl moieties. Furthermore, by using this approach, N‐ and S‐heteroarene analogues become accessible for the first time, as well as larger structures that represent derivatives of precursors for fullerene C60 or buckybowls. The attached tert‐butyl groups make all derivatives sufficiently soluble to allow full spectroscopic and electrochemical investigations. Postfunctionalization of selected derivatives for further synthetic applications of the compounds is also presented. 相似文献
910.
Jiaye Jin Prof. Guanjun Wang Prof. Mingfei Zhou Dr. Diego M. Andrada Dr. Markus Hermann Prof. Gernot Frenking 《Angewandte Chemie (International ed. in English)》2016,55(6):2078-2082
We report the spectroscopic identification of the [B3(NN)3]+ and [B3(CO)3]+ complexes, which feature the smallest π‐aromatic system B3+. A quantum chemical bonding analysis shows that the adducts are mainly stabilized by L→[B3L2]+ σ‐donation. 相似文献