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911.
Multiconfiguration Dirac-Fock (MCDF) method was employed to calculate the first five ionization potentials, electron affinities, resonance excitation energies, oscillator strengths, and radii for the element Uus and its homologue At. Main valence correlation effects were taken into account. The Breit interaction and QED effects were also estimated. The uncertainties of calculated IPs, EAs, and IR for Uus and At were reduced through an extrapolation procedure. The good consistency with available experimental and other theoretical values demonstrates the validity of the present results. These theoretical data therefore can be used to predict some unknown physicochemical properties of element Uus, Astatine, and their compounds. 相似文献
912.
Hyung-Geun Moon You-Sun Kim Jun-Pyo Choi Dong-Sic Choi Chang Min Yoon Seong Gyu Jeon Yong Song Gho Yoon-Keun Kim 《Experimental & molecular medicine》2010,42(1):47-60
Theophylline is commonly used to treat severe asthma and chronic obstructive pulmonary disease (COPD) characterized by non-eosinophilic inflammation. Acetyl salicylic acid (ASA) is one of the most widely used medications worldwide, but up to 20% of patients with asthma experience aggravated respiratory symptoms after taking ASA. Here we evaluated the adverse effect of ASA on the therapeutic effect of theophylline in mice with non-eosinophilic asthma. A non-eosinophilic asthma mouse model was induced by airway sensitization with lipopolysaccharide-containing allergen and then challenged with allergen alone. Therapeutic intervention was performed during allergen challenge. Theophylline inhibited lung inflammation partly induced by Th1 immune response. ASA attenuated the beneficial effects of theophylline. However, co-administration of the ASA metabolite salicylic acid (SA) showed no attenuating effect on theophylline treatment. The therapeutic effect of theophylline was associated with increase in cAMP levels, which was blocked by co-treatment of theophylline and ASA. ASA co-treatment also attenuated the anti-inflammatory effects of a specific phosphodiesterase 4 inhibitor. These results demonstrate that ASA reverses anti-inflammatory effects of theophylline, and that ASA exerts its adverse effects through the inhibition of cAMP production. Our data suggest that ASA reverses lung inflammation in patients taking theophylline, although clinical evidence will be needed. 相似文献
913.
Chang KS Yoshioka T Kanezashi M Tsuru T Tung KL 《Chemical communications (Cambridge, England)》2010,46(48):9140-9142
A new molecular dynamics simulation method was successfully applied to construct a homogeneous organic-inorganic hybrid silica membrane using the hybrid-pcff (h-pcff) potential function. Analysis suggested that the hybrid BTESE silica membrane provided a looser network and larger cavity size for the enhancement of gas permeability and selectivity. 相似文献
914.
Zhi‐Chang Liu Dr. Chih‐Hsien Chen Dr. Hsian‐Wen Wang Yen‐Chin Huang Ming‐Jui Kao Tsong‐Shin Lim Prof. Tien‐Yau Luh Prof. 《化学:亚洲杂志》2010,5(6):1425-1438
Polynorbornenes appended with porphyrins containing a range of different linkers are synthesized. The use of bisamidic chiral alanine linkers between the pending porphyrins and the polymeric backbone has been shown to bring the adjacent porphyrin chromophores to more suitable orientation for exciton coupling owing to hydrogen bonding between the adjacent linkers. The hydrogen bonding between the adjacent pendants in these polymers may induce a cooperative effect and therefore render single‐handed helical structures for these polymers. Such a cooperative effect is reflected in the enhancement of FRET efficiencies between zinc–porphyrin and free base porphyrin in random copolymers. 相似文献
915.
Lei H Wang Y Su C Liang F Su W Hui M Shaw P Luo Y 《Natural product communications》2010,5(10):1673-1676
The essential oils from leaves, twigs and stems of large trees and shrub-like trees of Thuja sutchuenensis were extracted by hydrodistillation and supercritical fluid extraction, and analyzed by GC and GC-MS. The essential oil composition differed significantly among the three organs, as well as between large trees and shrub-like trees. Furthermore, consistent with the eastern Asia-North American disjunct distribution of the genus, many differences in the essential oil composition between T. sutchuenensis and other Thuja species were apparent. The essential oils exhibited a certain degree of antifungal activity against six strains of human pathogenic fungi. 相似文献
916.
Yu CC Chen HW Chen MJ Chang YC Chien SC Kuo YH Yang FL Wu SH Chen J Yu HH Chao LK 《Natural product communications》2010,5(12):1941-1944
The present study investigated the chemical composition of Isochrysis galbana Parke, a marine microalga which is widely used as a feedstock in aquaculture. From gas chromatography/mass spectrometric analysis the mono-sugar compositions of I. galbana were 2.1% fucose, 2.5% rhamnose, 2.7% arabinose, 8.5% xylose, 15.7% mannose, 32.7% galactose and 35.8% glucose. The polysaccharides of I. galbana were able to induce prointerleukin-1beta (pro-IL-1beta) protein expression within murine macrophages. Furthermore, five kinds of chlorophyll and one sterol were separated from the ethanolic extracts, including pheophorbide-a, ethyl pheophorbide-a, 10S-10-hydroxypheophytin-a, 10R-10-hydroxypheophytin-a, (132-R)-pheophytin-a, and brassicasterol. In addition, the major soluble components of the ethanol/n-hexane extract were 9-octadecenoic acid (E) (38.4%), hexadecanoic acid (23.3%), tetradecanoic acid (15.7%), and octadecanoic acid (7.2%), but only a few polyunsaturated fatty acids were found, such as 9,12,15-octadecatrienoic acid (1.9%), 9,12-octadecadienoic acid (Z,Z) (3.4%), and docosahexaenoic acid (0.2%). This is the first occasion that polysaccharides from I. galbana have been demonstrated to exert immunomodulatory properties by the induction of IL-1 within macrophages. 相似文献
917.
T. Y. Wu M. H. Tsao F. L. Chen S. G. Su C. W. Chang H. P. Wang Y. C. Lin I. W. Sun 《Journal of the Iranian Chemical Society》2010,7(3):707-720
A series of new organic dyes comprising carbazole, iminodibenzyl, and phenothiazine moieties as the electron donors and rhodanine ring as the electron acceptor/anchoring groups were designed and developed for use in dye-sensitized solar cells. HOMO and LUMO energy level tuning was achieved by varying the carbazole, iminodibenzyls and phenothiazine donors. This was evidenced by spectral and electrochemical experiments and density functional theory calculations. Electrochemical studies indicated that the phenothiazine unit was much more effective in lowering the ionization potential than were the iminodibenzyl and carbazole units. The phenothiazine dye shows a solar-energy-to-electricity conversion efficiency (η) of 4.87%; the carbazole and iminodibenzyl dyes show η of 2.54% and 3.52%, respectively. These findings reveal that using carbazole, iminodibenzyl and phenothiazine donors as light-harvesting sensitizers are promising candidates for dye-sensitized solar cells. 相似文献
918.
Yu‐Bo Wang Tong‐Hen Pan Qian Liang Dong‐Sheng Liu Chang‐Cang Huang 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(5):m127-m129
The asymmetric unit of the title complex, [CdCl2(C14H12N4O2S)2]n, consists of one CdII ion located on the crystallographic inversion centre, one 4‐benzoyl‐1‐isonicotinoylthiosemicarbazide ligand and one chloride ligand. The central CdII ion adopts a distorted octahedral coordination geometry formed by two pyridyl N atoms of two ligands, two S atoms of two other ligands and two chloride ligands. The thiosemicarbazide ligands act as bridges, linking the metal ions into a two‐dimensional layered structure parallel to the bc plane. Intermolecular N—H...O hydrogen bonds and C—H...π interactions exist between adjacent layers. 相似文献
919.
Cui‐Yu Niu Jiao Jiao Bin Xing Gui‐Chang Wang Xian‐He Bu 《Journal of computational chemistry》2010,31(10):2023-2037
The decomposition mechanisms of methanol on five different Pt surfaces, the flat surface of Pt(111), Pt‐defect, Pt‐step, Pt(110)(1 × 1), and Pt(110)(2 × 1), have been studied with the DFT‐GGA method using the repeated slab model. The adsorption energies under the most stable configuration of the possible species and the activation energy barriers of the possible elementary reactions involved are obtained in this work. Through systematic calculations for the reaction mechanism of methanol decomposition on these surfaces, we found that such a reaction shows the same reaction mechanism on these Pt‐based model catalysts, that is, the final products are all H (Hads) and CO (COads) via O? H bond breaking in methanol and C? H bond scission in methoxy. These results are in general agreement with the previous experimental observations. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010. 相似文献
920.
Shu‐Wei Tang Jing‐Dong Feng Yong‐Qing Qiu Hao Sun Feng‐Di Wang Ying‐Fei Chang Rong‐Shun Wang 《Journal of computational chemistry》2010,31(14):2650-2657
Electronic structures and nonlinear optical properties of two highly deformed halofullerenes C3v C60F18 and D3d C60Cl30 have been systematically studied by means of density functional theory. The large energy gaps (3.62 and 2.61 eV) between the highest occupied and lowest unoccupied molecular orbitals (HOMOs and LUMOs) and the strong aromatic character (with nucleus‐independent chemical shifts varying from ?15.08 to ?23.71 ppm) of C60F18 and C60Cl30 indicate their high stabilities. Further investigations of electronic property show that C60F18 and C60Cl30 could be excellent electron acceptors for potential photonic/photovoltaic applications in consequence of their large vertical electron affinities. The density of states and frontier molecular orbitals are also calculated, which present that HOMOs and LUMOs are mainly distributed in the tortoise shell subunit of C60F18 and the aromatic [18] trannulene ring of C60Cl30, and the influence from halogen atoms is secondary. In addition, the static linear polarizability and second‐order hyperpolarizability of C60F18 and C60Cl30 are calculated using finite‐field approach. The values of and for C60F18 and C60Cl30 molecules are significantly larger than those of C60 because of their lower symmetric structures and high delocalization of π electrons. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010 相似文献