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911.
Wieczorek-Ciurowa K. Shirokov Ju. G. Paryło M. Gamrat K. 《Journal of Thermal Analysis and Calorimetry》2001,65(2):359-366
The chemical and physical processes occurring during grinding of copper hydroxocarbonates mixtures with aluminium were studied.
A planetary ball mill was used. A thermogravimetry and X-ray powder diffraction method allowed to determine the composition
of solid products after mechanical activation. The amount of the Cu2(OH)2CO3 undecomposed andAl2O3⋅3H2O, CuO, Al2O3, Cu0, CuxAly alloys and remained Al0 in the systems is strongly dependent on the duration of grinding and on the proportion of components.
The comparative results are presented.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
912.
Yong Nie Chun‐Hua Hu Xue Li Wei Yong Jian‐Min Dou Jie Sun Ruo‐Shui Jin Pei‐Ju Zheng 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(8):897-899
Each of the title compounds, 8‐methoxy‐7,7‐bis(triphenylphosphine‐P)‐8,9:10,11‐di‐μH‐7‐platina‐nido‐undecaborane dichloromethane hemisolvate, [Pt(CH14B10O)(C18H15P)2]·0.5CH2Cl2, (I), 8‐isopropoxy‐7,7‐bis(triphenylphosphine‐P)‐8,9:10,11‐di‐μH‐7‐platina‐nido‐undecaborane dichloromethane solvate, [Pt(C3H18B10O)(C18H15P)2]·CH2Cl2, (II), and 9‐isopropoxy‐7,7‐bis(triphenylphosphine‐P)‐8,9:10,11‐di‐μH‐7‐platina‐nido‐undecaborane dichloromethane solvate, [Pt(C3H18B10O)(C18H15P)2]·CH2Cl2, (III), has an 11‐vertex nido polyhedral skeleton, with the 7‐platinum centre ligating to two exo‐polyhedral PPh3 groups and an alkoxy‐substituted polyhedral borane ligand. Compounds (II) and (III) are isomers. The Pt—B distances are in the range 2.214 (7)–2.303 (7) Å for (I), 2.178 (16)–2.326 (16) Å for (II) and 2.205 (6)–2.327 (6) Å for (III). 相似文献
913.
AlxGa1−xAs LPE growth was studied within the temperature range of 930–900°C with Al concentrations in solutions from 0.04 to 2.4 at.%. AlAs concentration in layers has been shown to grow with the cooling rate increase of solution. Interface and volume nucleation parameter dependence of Ki and Kv and formation time tf on Al concentration in Ga solution have been found. Addition of Al to Ga solution increases critical values of As supersaturation (supercooling) and, as a result, increase in thickness of AlxGa1−xAs layers compared with GaAs layers have been determined in spite of As concentration lowering in Ga solution. 相似文献
914.
915.
干摩擦和水润滑条件下芳纶浆粕/环氧树脂复合材料摩擦磨损性能研究 总被引:4,自引:1,他引:3
研究了芳纶浆粕纤维增强环氧复合材料在干摩擦和水润滑条件下的摩擦磨损性能,探讨了纤维含量对复合材料摩擦磨损性能的影响,并分析了复合材料的磨损机理.结果表明:芳纶浆粕纤维能够大幅度提高环氧树脂的摩擦磨损性能;当纤维体积分数为40%时,复合材料的比磨损率最小;在水润滑条件下,复合材料的摩擦系数和磨损率均比干摩擦下的明显降低,这是由于水起到了润滑和冷却作用;干摩擦时的磨损机理为粘着磨损和塑性变形,水润滑时主要为犁削和轻微的磨粒磨损. 相似文献
916.
DNA酶中的G-四链体-血红素(G4-hemin)DNA酶结构具有较高的设计性和化学稳定性,因此格外受研究者关注.G-平面作为辅酶因子hemin的结合位点,不仅提供大π平面与hemin结合,而且其平面上的G碱基还可以充当近端配位基团与hemin进行配位.因此,研究G-平面完整性在G4-DNA酶体系中的作用具有重要意义.... 相似文献
917.
Xinquan Zhou Guifang Ju Tiansong Dai Yang Li Haoyi Wu Yahong Jin Yihua Hu 《化学:亚洲杂志》2019,14(9):1506-1514
Near‐infrared (NIR) long‐persistent phosphors (LPPs) have emerged as a potential solution for bio‐imaging applications over the past few years. However, there are enormous challenges regarding their in situ application based on their dependence on short‐wavelength excitation. In this paper, we report a multi‐spectral excited NIR LPP, Li5Zn8Ga5Ge9O36: 1.5 % Cr3+, 0.5 % Ti4+, which overcomes the limitations of functional processes in biological tissues and other complex systems. This LPP exhibits a high luminescent intensity and a long emission duration in the NIR region (700–800 nm). The applicability of this phosphor to tissue imaging is demonstrated experimentally. Its persistent luminescence (PersL) can easily penetrate approximately 2 mm of pork flesh. More importantly, this phosphor can be re‐charged in situ using a red LED or laser diode array to provide renewed NIR PersL for biological tissues, which is beneficial for long‐term biological tissue imaging applications with high signal‐to‐noise ratios. Systematic investigations of the nature of energy traps and PersL mechanisms are also reported in this paper. 相似文献
918.
Peiwen Zhang Yiran Li Xiaofei Yu Prof. Dr. Huangxian Ju Prof. Dr. Lin Ding 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(44):10505-10510
Precision cell-selective surface glycan remodeling is of vital importance for modulation of cell surface dynamics, tissue-specific imaging, and immunotherapy, but remains an unsolved challenge. Herein, we report a switchable enzymatic accessibility (SEA) strategy for highly specific editing of carbohydrate moieties of interest on the target cell surface. We demonstrate the blocking of enzyme in the inaccessible state with a metal-organic framework (MOF) cage and instantaneous switching to the accessible state through disassembly of MOF. We further show that this level of SEA regulation enables initial guided enzyme delivery to the target cell surface for subsequent cell-specific glycan remodeling, thus providing a temporally and spatially controlled tool for tuning the glycosylation architectures. Terminal galactose/N-acetylgalactosamine (Gal/GalNAc) remodeling and terminal sialic acid (Sia) desialylation have been precisely achieved on target cells even with other cell lines in close spatial proximity. The SEA protocol features a modular and generically adaptable design, a very short protocol duration (ca. 30 min or shorter), and a very high spatial resolving power (ability to differentiate immediately neighboring cell lines). 相似文献
919.
Song Zhang Hu‐jun Qian Zhonghua Liu Hongyu Ju Zhong‐yuan Lu Haiming Zhang Lifeng Chi Shuxun Cui 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(6):1673-1677
Since the discovery of amorphous red phosphorus (a‐red P) in 1847, many possible structures have been proposed. However, the exact molecular structure has not yet been determined because of its amorphous nature. Herein several methods are used to investigate basic properties of a‐red P. Data from scanning tunneling microscopy (STM) and gel permeation chromatography (GPC) confirm that a‐red P is a linear inorganic polymer with a broad molecular weight distribution. The theoretical single‐molecule elasticities of the possible a‐red P structures are obtained by quantum mechanical (QM) calculations. The experimental single‐molecule elasticity of a‐red P measured by single‐molecule AFM matches with the theoretical result of the zig‐zag ladder structure, indicating that a‐red P may adopt this structure. Although this conclusion needs further validation, this fundamental study represents progress towards solving the structure of a‐red P. It is expected that the strategy utilized in this work can be applied to study other inorganic polymers. 相似文献