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991.
含氮宾的两个三核羰基铁簇合物是由[Et_3NH][HFe_3(CO)_(11)]与C_6H_5NCO在苯中反应获得。应用四园衍射仪测定了H_2Fe_3(N-C_6H_5)(CO)_9(Ⅰ)和Fe_3(N-C_6H_5)(μ_3-CO)(CO)_9(Ⅱ)的晶体结构。晶体数据为:C_(15)H_7NO_9Fe_3(Ⅰ),空间群P2_1/a,a=18.343(2),b=9.072(1),c=11.451(1)(?),β=102.03(1)°,V=1863.7(?)~3,Z=4,D_c=2.143g/cm~3;C_(16)H_5NO_(10)Fe_3(Ⅱ),空间群P2_1/c,a=8.634(1),b=13.026(1),c=17.642(2)(?),β=97.68(1)°,V=1966.3(?)~3,Z=4,D_c=1.820g/cm结构系用直接法解出,最后R_(Ⅰ)因子为0.033,R_(Ⅱ)因子为0.027。测定结果表明,(Ⅰ)和(Ⅱ)分子均具有C_s对称性,且三个Fe原子共面,呈近似等边三角形结构。(Ⅰ)中面桥N原子以不对称方式与三个Fe原子成键;(Ⅱ)中面桥羰基以不对称方式与三个Fe原子键连。Fe-N和Fe-C键长分别在1.896-1.938(?)和2.006-2.110(?)之间。 相似文献
992.
新定义的价连接性指数与有机物理化活性的相关性研究 总被引:6,自引:0,他引:6
基于分子中成键原子i的结构特征和所处的化学环境,新定义了原子的价点价δYi,以价连接矩阵为基础构建了一个新的能表征含多重键、杂原子分子结构信息的价连接性指数mωY. mωY对有机化合物异构体具有很强的选择性和区分能力.用0ωY, 1ωY和分子中的含碳数NC研究了有机物的一系列理化活性,其相关性良好,并发现不同的性质,0ωY, 1ωY和NC所起的作用程度是有所不同的.新模型物理意义明确,计算简便,对不同类型有机物的不同理化活性具有良好的估算和预测能力,计算值与实验值的吻合程度均优于相应文献的结果. 相似文献
993.
Summary Electronic structure of hydrogen nitryl HNO2, a yet not identified entity, and the path of its possible isomerization totrans-HONO have been investigated byab initio SCF and MRD-CI computations using the 6-31G** basis set. HNO2 isC
2v
-symmetric and its ground state (1
A
1) is less stable thantrans-HONO by 66 kJ/mol (with the SCF vibrational zero-point energy correction). The lowest two excited singlet states (1
A
2 and1
B
1) are nearly degenerate, their vertical excitation energies being predicted to be 4.8 eV. The isomerization path is traced by the CASSCF procedure and the activation barrier height is evaluated by the CI treatment. HNO2 in its ground state isomerizes totrans-HONO by maintaining the planar (C
s-symmetric) structure. The activation energy is calculated to be 171 kJ/mol, which is clearly lower than the calculated H-N bond energy (253 kJ/mol). The transition state seems to be more adequately described as an interacting system of proton and the nitrite anion rather than as a pair of two fragment radicals. 相似文献
994.
995.
主体分子六次甲基四胺与客体分子二氯化六水合钴(Ⅱ)和结晶水包结物的研究 总被引:1,自引:0,他引:1
用X射线单晶衍射分析法研究主体分子六次甲基四胺与客体分子二氯化六水合钴(Ⅱ)和结晶水包结物晶体结构。其分子式为[(CH2)6N4]2·[(Co(H2O)6]Cl2·4H2O,Mr=59038。晶体属三斜晶系,空间群为P1。晶胞参数:3341个衍射点,其中3148个独立衍射点,2754(F0>6σ(F0))为可观察反射点。在晶胞内,客体分子和结晶水形成氢键:,客体分子与主体分子形成氢键晶胞之间形成氢键晶胞之内和晶胞之间主体分子和客体分子以及结晶水以氢键和范德华力相联系形成稳定的晶格。 相似文献
996.
997.
The structures of the inclusion compounds formed by the host 9,9’-(ethyne-1,2-diyl)bis(fluoren-9-01) with pyridine and picolines are similar and display tubular topology. The host discriminates poorly between
these guests. The kinetics of desorption of the pyridine compound is governed by the Avrami-Erofe’ev equation A2, with an
activation energy of 111(7) kJ mol−1. 相似文献
998.
Kun Guo YANG Rui Mao HUA* Hai WANG Bo Qing XU* Department of Chemistry Tsinghua University Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education Beijing Department of Chemistry Chemical Engineering Guangxi Normal University Guilin 《中国化学快报》2005,16(4)
Diphenylmethane and substituted diphenylmethane are important compounds forsynthesis chemistry as well as industrial chemistry. These compounds are easilysynthesized by the benzylation of aromatic compounds with benzyl chloride or benzylalcohol catalyzed by homogeneous acid catalysts, such as AlCl3, FeCl3, H2SO4, HF andBF3. However, these catalytic systems are highly corrosive, and usually proceed withlow selectivity. In addition, they are less satisfactory from the environmen… 相似文献
999.
Riccò M Shiroka T Carretta S Bolzoni F Femoni C Iapalucci MC Longoni G 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(9):2856-2861
The magnetic behaviour of the even-electron [Ni16Pd16(CO)40]4- cluster, in its [NnBu4]+ salt, has been investigated by magnetometry and muon spin rotation/relaxation (muSR) spectroscopy. The susceptibility measurements show an exceptionally high magnetic moment corresponding to a total spin value J=2. This suggests a Hund filling of a quadruplet ground state, quite unique in carbonyl-metal clusters. SQUID magnetometry shows a departure from the Curie-Weiss law, for T>150 K, and strong deviation from a Brillouin behaviour of the magnetisation curves. muSR spectroscopy in zero applied field shows a temperature independent decay of the muon spin polarisation, similar to that of a purely paramagnetic system. The observed muon spin repolarisation in a moderate external longitudinal field, however, invalidates this simple picture and suggests the presence of a local anisotropy field acting on the cluster's magnetic moment. A consistent interpretation of magnetometry and muSR results implies the occurrence of an additional interaction of the cluster spin with an effective crystalline field. The inclusion of this interaction in a model Hamiltonian allows us to successfully reproduce both the susceptibility and magnetisation data. 相似文献
1000.