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151.
152.
M. Salih Ağırtaş Emrah Dede Selçuk Gümüş Abdurrahman Dündar Veysi Okumuş 《无机化学与普通化学杂志》2014,640(10):1953-1959
A novel phthalonitrile derivative bearing 2‐isopropyl‐6‐methylpyrimidin‐4‐yloxy substituents at peripheral positions was synthesized by a nucleophilic substitution reaction. Metallophthalocyanines were obtained from the reaction of the novel phthalonitrile with metal Zn, Cu, Co, and Ni salts. The characterization of the compounds was performed using elemental analysis as well as UV/Vis, FT‐IR, and 1H‐NMR spectroscopy. The aggregation behaviors of phthalocyanine complexes were also investigated. These metallophthalocyanines do not show any aggregation behavior between 10–4–10–6 M concentration range in THF. The antioxidant activities of the synthesized compounds were evaluated using three different tests: 2, 2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging, metal chelating activity, and reducing power assays. All the compounds exhibited various antioxidant activities. In addition, antimicrobial activity of the compounds was tested over four gram positive and two gram negative bacteria. Moreover, the ground‐state geometries of the complexes were optimized using density functional theory (DFT) methods at B3LYP/6‐31G(d, p) level in order to obtain information about the 3D arrangements and electronic structure. 相似文献
153.
运用密度泛函理论结合非平衡格林函数的方法对MgB2直线原子链与两半无限Au(100)电极构成纳米结点的电子输运特性进行了第一性原理计算.在模拟Au-MgB2-Au纳米结点的拉伸过程中,计算了结点在不同距离下的结合能与电导.结果发现结点的Au-B键长为1.90A,B-Mg键长为2.22A时,结合能最大,结构最稳定,此时结点平衡电导为0.51G0(G0=2e^0/h).通过计算投影态密度发现电子通过结点时主要是通过B、Mg原子的px和py电子轨道形成的π键进行传输的.在-1.5~1.5V的电压范围内,结点的电流-电压近似为线性关系,表现出类似金属的导电性质,而当正负电压高于15V时,电流对称性逐渐减小,即存在负微分电阻效应,从不同电压下透射谱的变化对负微分电阻现象进行了分析与讨论. 相似文献
154.
In this work, the ab-initio coupled cluster CCSD(T) method and the B3LYP, BP91W and CAM-B3LYP functional of DFT method in conjunction with the aug-cc-pVTZ-PP basis have been applied to study the group 12 monocarbides MC, MC+ and MC?. The potential energy curves (PECs) for the three electronic states 3Σ?, 5Σ? and 1Δ of the MC and the two states 2∑- and 4∑- for the MC+ cations and MC? anions have been investigated. In addition, Bond distance Re, transition energy Te, vibrational frequency ωe, ionization energy IE, electron affinity EA, dipole moment μ, dissociation energy D0 and heat formation ΔH°f0/ΔH°f298, were determined for each species. The analysis of the dissociation energy for ZnC, CdC and HgC shows the decrease in the stability of the monocarbides from Zn to Hg. For ΔH°f0/ΔH°f298 values of MC, which are not known experimentally or theoretically, we recommend the following CCSD(T) predictions of ZnC, CdC and HgC: 181.3/178.54, 180.65/178.4 and 175.35/174.71 kcal/mol respectively. Comparing the three functionals with the CCSD(T) results, the CAM-B3LYP functional shows excellent predictive agreement for the various properties of the group 12 monocarbides. 相似文献
155.
纤维及织物因具有良好的柔性、透气性以及适宜的力学性能而成为人们日常生活必不可少的材料。随着柔性电子器件的快速发展,纤维及织物在其自身优势的基础上,开始被人们赋予智能化特征,使得智能纤维和织物逐渐在可穿戴领域占据一席之地。天然蚕丝具有产量大、机械性能优异和生物可降解的优势。近年来,面向智能应用的蚕丝基纤维与织物逐渐发展,被用于传感、致动、光学器件、能量收集和储能等领域。本文将首先介绍天然蚕丝的层级结构和性能,并介绍各种形貌结构的再生蚕丝材料;然后根据其在智能纤维及织物中应用领域的不同,详细阐述蚕丝基智能纤维及织物的制备方法、性能及工作机制;最后讨论进一步发展所面临的挑战与机会,并对未来前景进行展望。 相似文献
156.
《中国化学快报》2021,32(10):3149-3154
In this paper, a novel BC3N2 monolayer has been found with a graphene-like structure using the developed particle swarm optimization algorithm in combination with ab initio calculations. The predicted structure meets the thermodynamical, dynamical, and mechanical stability requirements. Interestingly, the BC3N2 plane shows a metallic character. Importantly, BC3N2 has an in-plane stiffness comparable to that of graphene. We have also investigated the adsorption characteristics of CO2 on pristine monolayer and Mo functionalized monolayer using density functional theory. Subsequently, electronic structures of the interacting systems (CO2 molecule and substrates) have been preliminarily explored. The results show that Mo/BC3N2 has a stronger adsorption capacity towards CO2 comparing with the pristine one, which can provide a reference for the further study of the CO2 reduction mechanism on the transition metal-functionalized surface as well as the new catalyst’s design. 相似文献
157.
158.
The electronic properties of SiC nanotubes (SiCNTs) under external transverse electric field were investigated using density functional theory. The pristine SiCNTs were semiconductors with band-gaps of 2.03, 2.17 and 2.25 eV for (6,6), (8,8) and (10,10) SiCNTs, respectively. It was found the band gaps was reduced with the external transverse electric filed applied. The (8,8) and (10,10) SiCNTs changed from semiconductor to metals as the intensity of electric field reached 0.7 and 0.5 V/Å. The results indicate that the electronic properties of SiCNTs can be tuned by the transvers electric field with integrality of the nanotubes. 相似文献
159.
SiC is a highly stable material in bulk. On the other hand, alloys of silicon and carbon at nanoscale length are interesting from both technological as well fundamental view point and are being currently synthesized by various experimental groups (Truong et. al., 2015 [26]). In the present work, we identify a well-known silicon cluster viz., Si10 and dope it sequentially with carbon atoms. The evolution of electronic structure (spin state and the structural properties) on doping, the charge redistribution and structural properties are analyzed. It is interesting to note that the ground state SiC clusters prefer to be in the lowest spin state. Further, it is seen that carbon atoms are the electron rich centres while silicon atoms are electron deficient in every SiC alloy cluster. The carbon–carbon bond lengths in alloy clusters are equivalent to those seen in fullerene molecules. Interestingly, the carbon atoms tend to aggregate together with silicon atoms surrounding them by donating the charge. As a consequence, very few Si–Si bonds are noted with increasing concentrations of C atoms in a SiC alloy. Physical and chemical stability of doped clusters is studied by carrying out finite temperature behaviour and adsorbing O2 molecule on Si9C and Si8C2 clusters, respectively. 相似文献
160.
The electronic structures and magnetic behaviors of graphene with 5d series transition metal atom substitutions are investigated by performing first-principles calculations. All the impurities are tightly bonded to single vacancy in a graphene sheet. The substitutions of La and Ta lead to Fermi level shifting to valence and conduction band, respectively. Both the two substitutions result in metallic properties. Moreover, the Hf, Os and Pt-substituted systems exhibit semiconductor properties, while the Re and Ir-substituted ones exhibit robust half-metallic properties. Interestingly, W-substituted system shows dilute magnetic semiconductor property. On the other hand, the substitution of Ta, W, Re and Ir induce 0.86 μB, 2 μB, 1 μB and 0.99 μB magnetic moment, respectively. Our studies demonstrate that the 5d series transition metal substituted graphene have potential applications in nanoelectronics, spintronics and magnetic storage devices. 相似文献