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841.
Yasutaka Omori Shinji Tokonami Tetsuo Ishikawa Sarata Kumar Sahoo Naofumi Akata Atsuyuki Sorimachi Masahiro Hosoda Chanis Pornnumpa Paitoon Wanabongse Hiromi Kudo Ye-Jing Hu Yong-Xiang Ao Xiao-Liang Li Kun Li Ying-Hua Fu Quan-Fu Sun Suminori Akiba 《Journal of Radioanalytical and Nuclear Chemistry》2015,306(1):317-323
842.
843.
Shinji Ando Tohru Matsuura Shigekuni Sasaki 《Journal of polymer science. Part A, Polymer chemistry》1992,30(11):2285-2293
We measured the 15N-, 1H-, and 13C-NMR chemical shifts for a series of aromatic diamines and aromatic tetracarboxylic dianhydrides dissolved in DMSO-d6, and discuss the relationships between these chemical shifts and the rate constants of acylation (k) as well as such electronic-property-related parameters such as ionization potential (IP), electronic affinity (EA), and the energy ε of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). The 15N chemical shifts of the amino group of diamines (δN) depend monotonically on the logarithm of k (log k) and on IP. We inferred the reactivities of diamines whose acylation rates have not been measured from their δN, and we propose an arrangement of diamines in the order of their reactivity. The 1H chemical shift of amino hydrogens (δH) and the 13C chemical shift of carbons bonded to nitrogen (δC) are roughly proportional to δN, but these shifts are not as closely correlated with log k and IP. Although the 13C chemical shifts of the carbonyl carbon of dianhydrides (δC,) varies much less than the δC and δN of diamines, δC, can be an index of acylation reactivity for dianhydrides because it is closely correlated with εLUMO. These facts indicate that the chemical shifts of diamines and dianhydrides are displaced according to their electron-donor and electron-acceptor properties, and that these chemical shifts can be used as indices of the electronic properties of monomers. Changes in reactivity caused by the introduction of trifluoromethyl groups into diamines and dianhydrides are inferred from the displacements of δN and δC © 1992 John Wiley & Sons, Inc. 相似文献
844.
Hiromi Sakai Shinji Takeoka Hiroaki Yokohama Hiroyuki Nishide Eishun Tsuchida 《先进技术聚合物》1992,3(7):389-394
A carbonyl hemoglobin (HbCO) solution was stirred with a mixed powder of polymerizable 1,2-bis(2,4-octadecadienoyl)-sn-glycero-3-phosphocholine (DODPC), cholesterol and stearic acid (7/7/2 by mol). The mixture was extruded through polycarbonate membrane filters (final pore size = 0.2 μm Ø). The average diameter of the resulting vesicles was 203 ± 39 nm. The [Hb]/[Lipid] ratio (the weight ratio of Hb in vesicle to lipid) increased with the Hb concentration, and decreased with the NaCl concentration. A maximum [Hb]/[lipid] ratio was observed at pH 6.9, which was the same as the isoelectric point of Hb. The vesicles were stabilized by γ-irradiation (60Co) because the bilayer lipids bound each other to yield polyphospholipids. Denaturation of Hb by γ-irradiation was not detected. These polyphospholipid vesicles encapsulating Hb were stable even against the freeze–thaw cycles and the freeze-drying procedure. 相似文献
845.
Ruthenium complexes, e.g., RuH2(CO)(PPh3)3, have been found to catalyze the direct addition of ortho carbon-hydrogen bonds of aromatic ketones to olefins and acetylenes with high efficiency and selectivity. The C-H/olefin coupling reaction is applicable to not only C-H bonds in aromatic ketones but also to those in a,b-enones and aro-matic esters. Catalytic addition of ortho carbon-hydrogen bonds of aromatic imines to olefins is found to be catalyzed by Ru3(CO)12. 相似文献
846.
Prof. Dr. Shinji Harada Ryotaro Koyama Ryuya Masuda Prof. Dr. Shigeru Arai 《European journal of organic chemistry》2023,26(38):e202300747
A trichloromethylative olefin lactonization reaction using an iridium photoredox catalyst was developed. The reactions proceeded at room temperature for olefins with various substituents and substitution patterns, and a variety of lactones with a tetrasubstituted carbon and trichloromethyl group were obtained regio- and stereoselectively. The reaction mechanism was elucidated through isotope labeling experiments. The chemical properties of the lactones containing the trichloromethyl groups were investigated, and synthetic transformations of the product were realized. 相似文献
847.
Acridone units were incorporated into the arylene–ethynylene structure as polar arene units. Cyclic trimers consisting of three acridone-2,7-diyl units and three 1,3-phenylene units were synthesized by Sonogashira couplings via stepwise or direct route. X-ray analysis revealed that the trimer had a nearly planar macrocyclic framework with a cavity surrounded by three carbonyl groups. In contrast, the corresponding tetramer had a nonplanar macrocyclic framework. 1H NMR measurements showed that the trimer formed a 1 : 1 complex as a macrocyclic host with dihydric phenol guests, and the association constants were determined to be ca. 1.0×103 L mol−1 for hydroquinone or resorcinol guests in CDCl3 at 298 K. The calculated structures of these complexes by the DFT method supported the presence of two sets of OH⋅⋅⋅O=C hydrogen bonds between the host and guest molecules. The spectroscopic data of the cyclic trimers and tetramers are compared with those of reference acridone compounds. 相似文献
848.
Takeshi Takeda Toshio Tsuchida Ichiro Nakagawa Shinji Ogawa Tooru Fujiwara 《Tetrahedron letters》1985,26(43):5313-5316
β-Phenylthioalkyltitanium reagent prepared by the hydrotitanation of alkenyl sulfide using triethylsilane and titanium tetrachloride is found to react with aromatic aldehyde or α,β-unsaturated ketone to give the corresponding γ-hydroxyalkyl sulfide or δ-phenylthio ketone, respectively. 相似文献
849.
850.
The unidirectional thermal ring-closing reaction of cis-4-phenyl-5-borylpenta-1,2,4-triene giving 4-boryl-3-methylene-1-phenylcyclobutene proceeded significantly faster than that of the trans-isomer. The large rate difference between the cis- and trans-stereoisomers is ascribed to electronic participation of the vacant boron p orbital in the transition state SHOMO. 相似文献