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991.
992.
Yin‐Feng Wang Qing Wang Zhuo Li Zhi‐Ru Li Jiangen Huang Jiuhui Liu Guangpei Zhou 《Journal of Physical Organic Chemistry》2012,25(8):674-679
How does the endo C–F bond influence the excess electron binding motif? For lithium‐doped endohedral perfluorofullerenes with endo C–F bonds, under both internal‐push (from exo C–F bonds) and external‐push (from endo C–F bonds) electron effects, the singly occupied molecular orbital electron cloud of the sphere‐like Li···F8@C60F52 (D2) is partially dispersed within the σp–s antibonding orbital of endo C–F bonds and the space between Cδ+–Fendoδ– double electric layers, which makes Li···F8@C60F52 have partial excess electron (electride characteristics) and partial lithium salt characteristics, while in the tube‐like Li···F2@C60F58 (Cs), as the Li is changing from approaching F to keeping away from F and to approaching another one, the singly occupied molecular orbital electron cloud is mainly dispersed from within the p orbital of the short endo C–F bond to within the middle of the two F atoms and again to within the p orbital of the short endo C–F bond, which indicates an evolution from lithium salt characteristic to excess electron characteristic, and again to lithium salt characteristic. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
993.
《Journal of Coordination Chemistry》2012,65(6):1021-1039
[Cu(L)] (1) and mixed ligand copper(II) complexes [Cu(L)(A)] (2 and 3), where L is the Schiff base derived from o-vanillin and l-tryptophan and A is pyridine (2) and imidazole (3), were synthesized and characterized using conventional and spectral techniques. 2 was structurally characterized using single crystal X-ray crystallography showing that Cu(II) is coordinated through N2O2 donors in a square plane. The EPR spectra of the complexes in frozen solution support a square-based structure. Electrochemical behavior of the complexes has been studied by cyclic voltammetry. The DNA-binding properties of L and 1–3 with calf thymus DNA were investigated by spectral and kinetic methods. For all the complexes, the maximum value of binding constant (0.38 × 106) was achieved with 3 by spectroscopic titration. The ability of compounds to break pUC19 DNA was checked by gel electrophoresis. The ligand and copper complexes exert cytotoxicity against MCF-7 cell line. 相似文献
994.
《Journal of Coordination Chemistry》2012,65(4):660-669
Tris(N-ethylbenzimidazol-2-ylmethyl)amine (Etntb), [Mn(Etntb)(DMF)(H2O)](pic)2 (1), and [Ni(Etntb)(DMF)(H2O)](pic)2 (2) (pic?=?picrate) have been synthesized and characterized by elemental analyses, molar conductivities, UV–Visible spectra, and IR spectra. Single-crystal X-ray diffraction revealed that the complexes have the same arrangement with distorted octahedral coordination geometries. DNA-binding properties of the free ligand, 1, and 2 have been investigated by electronic absorption, fluorescence, and viscosity measurements. The results suggest that the ligand and its complexes bind DNA via intercalation, and their binding affinity for DNA follows the order 2?>?1?> ligand. 相似文献
995.
《Journal of Coordination Chemistry》2012,65(24):4268-4279
Two cobalt(II) complexes [Co(QCT)2]·Cl·1.5H2O (1) (QCT = quinoline-2-carboxaldehyde thiosemicarbazone) and [Co(QCMT)(CH3OH)Cl2] (2) (QCMT = quinoline-2-carboxaldehyde N4-methyl-thiosemicarbazone) have been synthesized and structurally characterized. Complex 1 crystallizes in a triclinic system with space group P–1 and complex 2 crystallizes in a monoclinic system with space group P2(1)/n. In both complexes the cobalt(II) center is six coordinated with distorted octahedral geometry. The interactions of two complexes with CT-DNA were investigated by electronic absorption spectra, circular dichroism (CD) spectra and fluorescence spectra. Results suggest that the complexes bind to DNA via groove binding mode, and complex 2 has stronger binding ability than complex 1. The in vitro cytotoxicity has been tested against the human lung adenocarcinoma cell line A-549, cisplatin-resistant cell line A-549/CDDP, and human breast adenocarcinoma cell line MCF-7. Complex 2 is more cytotoxic than complex 1, and both of them show higher cytotoxicity than the parent ligands alone. Compared with cisplatin, the two cobalt(II) complexes are more active against A-549/CDDP and MCF-7 cell lines at most experimental concentrations. Notably, although complex 2 is found to be less effective than cisplatin against the parent cell line A-549, it is much more effective than cisplatin against the resistant cell A-549/CDDP. 相似文献
996.
《Journal of Coordination Chemistry》2012,65(12):2148-2159
Ferrocene incorporated N,N′-disubstituted thioureas (S1–S6) were synthesized by allowing 4-ferrocenyl-3-methylaniline to react with freshly prepared aliphatic isothiocyanates and were characterized by using different analytical techniques. Based on single-crystal X-ray analysis compound S1 shows supramolecular structure mediated by secondary bonding interactions, intermolecular hydrogen bonding NH–O, NH–S, and secondary non-covalent interactions (π–H). Voltammetric measurements were used to study their redox behavior and DNA binding of the compounds. Different binding parameters like binding constants, binding energies, and diffusion coefficients (Do) were calculated for further insight on the affinity with DNA. All the compounds show electrostatic mode of interactions. The Do of molecule-DNA adducts were found to be lower than that of free molecule. Compounds S1–S6 having 50% inhibition values less than 37.89?μg?mL?1 indicate that they may have value as antioxidants to be used as therapeutic agents. 相似文献
997.
《Journal of Coordination Chemistry》2012,65(1):115-123
Three new reduced amino-acid Schiff-base complexes, [Zn(HL)2] · H2O (1), [Ni(HL)2] · H2O (2), and [Cd(HL)2] · H2O (3), where H2L is a reduced Schiff base derived from condensation of N-(2-hydroxybenzaldehyde) and L-histidine, have been synthesized and characterized by elemental analysis, UV-Vis absorption spectra and single crystal X-ray diffraction. Complexes 1–3 are isostructural. All metal centers are six-coordinate with O2N4 donor sets in slightly distorted octahedra. Unlike its Schiff-base counterpart, the deprotonated monoanionic ligand HL? has a more flexible backbone and two HL? are tridentate to one metal. Moreover, the binding interactions of these complexes with calf thymus DNA (CT-DNA) have been investigated by UV-Vis spectra and fluorescence quenching, which show that the complexes bind in an intercalative mode. 相似文献
998.
《Journal of Coordination Chemistry》2012,65(11):1295-1300
The novel metallobenzylmalonate [Pd(bipy)(bmal)]?·?2H2O (bipy?=?2,2′-bipyridyl, bmal?= benzylmalonate) has been synthesized and structurally characterized by element analyses, electronic spectroscopy, electrophoresis and single-crystal X-ray diffraction. The complex is orthorhombic, space group Pna21, with a?=?7.637(2), b?=?13.018(4), c?=?20.961(7)?Å, V?=?2083.8(12)?Å3, Z?=?4. Pd(1) is four coordinated by two nitrogen atoms from the bipy ligand and two oxygen atoms from bmal with square planar geometry. In the lattice, π–π stacking and hydrogen bonding are the main intermolecular interactions and propitious for non-covalent insertion into DNA molecules. Electronic spectra confirm that the main reaction mode of the compound with DNA is non-covalent. Electrophoresis shows the cleavage of both supercoiled and circular DNA to form small molecular fragments under the action of the complex. The complex shows excellent anti-cancer activity towards lung cancer AGZY-83a. 相似文献
999.
《Journal of Coordination Chemistry》2012,65(12):2054-2064
Two iron(II) complexes, [FeII(pytBuN3)2](FeCl4) (1) and [FeII(pytBuMe2N3)Cl2] (2), with sterically constrained pytBuN3 and pytBuMe2N3 chelate ligands (pytBuN3 = 2,6-bis-(aldiimino)pyridyl; pytBuMe2N3 = 2,6-bis-(ketimino)pyridyl), have been synthesized and characterized by elemental analysis, IR, UV–vis spectra, and preliminary X-ray single-crystal diffraction. The latter revealed that Fe(II) in 1 is six-coordinate by six nitrogen donors from two bisiminopyridines in a distorted octahedron. Complex 2 reacts with thiourea with a second-order rate constant k2 = (2.50 ± 0.05) × 10?3 M?1 s?1 at 296 K, and the reaction seemed to be slow. In a similar way, the interaction of 2 and DNA was studied by fluorescence and absorption spectroscopy. The results revealed that 2 caused fluorescence quenching of DNA through a dynamic quenching procedure. The binding constants KA, Kapp, and KSV as well as the number of binding sites between 2 and DNA were determined. 相似文献
1000.