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991.
Striking Differences in Properties of Geometric Isomers of [Ir(tpy)(ppy)H]+: Experimental and Computational Studies of their Hydricities,Interaction with CO2, and Photochemistry 下载免费PDF全文
Dr. Komal Garg Dr. Yasuo Matsubara Dr. Mehmed Z. Ertem Dr. Anna Lewandowska‐Andralojc Dr. Shunsuke Sato Dr. David J. Szalda Dr. James T. Muckerman Dr. Etsuko Fujita 《Angewandte Chemie (International ed. in English)》2015,54(47):14128-14132
We prepared two geometric isomers of [Ir(tpy)(ppy)H]+, previously proposed as a key intermediate in the photochemical reduction of CO2 to CO, and characterized their notably different ground‐ and excited‐state interactions with CO2 and their hydricities using experimental and computational methods. Only one isomer, C‐trans‐[Ir(tpy)(ppy)H]+, reacts with CO2 to generate the formato complex in the ground state, consistent with its calculated hydricity. Under photocatalytic conditions in CH3CN/TEOA, a common reactive C‐trans‐[Ir(tpy)(ppy)]0 species, irrespective of the starting isomer or monodentate ligand (such as hydride or Cl), reacts with CO2 and produces CO with the same catalytic efficiency. 相似文献
992.
Phosphine‐Catalyzed β,γ‐Umpolung Domino Reaction of Allenic Esters: Facile Synthesis of Tetrahydrobenzofuranones Bearing a Chiral Tetrasubstituted Stereogenic Carbon Center 下载免费PDF全文
Dr. Shinobu Takizawa Kenta Kishi Dr. Yasushi Yoshida Steffen Mader Dr. Fernando Arteaga Arteaga Shoukou Lee Dr. Manabu Hoshino Prof. Dr. Magnus Rueping Prof. Dr. Makoto Fujita Prof. Dr. Hiroaki Sasai 《Angewandte Chemie (International ed. in English)》2015,54(51):15511-15515
An enantio‐, diastereo‐, regio‐, and chemoselective phosphine‐catalyzed β,γ‐umpolung domino reaction of allenic esters with dienones has been developed for the first time. The designed sequence, involving oxy‐Michael and Rauhut–Currier reactions, produced highly functionalized tetrahydrobenzofuranones, bearing a chiral tetrasubstituted stereogenic center, in up to 96 % ee. 相似文献
993.
Zegers RG Adachi T Akimune H Austin SM van den Berg AM Brown BA Fujita Y Fujiwara M Galès S Guess CJ Harakeh MN Hashimoto H Hatanaka K Hayami R Hitt GW Howard ME Itoh M Kawabata T Kawase K Kinoshita M Matsubara M Nakanishi K Nakayama S Okumura S Ohta T Sakemi Y Shimbara Y Shimizu Y Scholl C Simenel C Tameshige Y Tamii A Uchida M Yamagata T Yosoi M 《Physical review letters》2007,99(20):202501
Differential cross sections for transitions of known weak strength were measured with the (3He, t) reaction at 420 MeV on targets of 12C, 13C, 18O, 26Mg, 58Ni, 60Ni, 90Zr, 118Sn, 120Sn, and 208Pb. Using these data, it is shown that the proportionalities between strengths and cross sections for this probe follow simple trends as a function of mass number. These trends can be used to confidently determine Gamow-Teller strength distributions in nuclei for which the proportionality cannot be calibrated via beta-decay strengths. Although theoretical calculations in the distorted-wave Born approximation overestimate the data, they allow one to understand the main experimental features and to predict deviations from the simple trends observed in some of the transitions. 相似文献
994.
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996.
Shirakawa M Fujita N Tani T Kaneko K Ojima M Fujii A Ozaki M Shinkai S 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(15):4155-4162
8-quinolinol/copper(II)-, palladium(II)-, and platinum(II)-chelate-based organogelators (1 M) and their nongelling reference compounds (2 M) were synthesized. Complexes 1 M could gelate various organic solvents at very low concentrations. Electron microscope measurements gave visual images of well-developed fibrous structures characteristic of low-molecular-weight organogels. UV/Vis and FTIR spectroscopy revealed that the good gelation ability of 1 M arises from the pi-pi interactions of the chelate moieties and the hydrogen-bond interactions among the amide groups. Very interestingly, field emission performances of the nanofibers prepared from the 1 M gels are evidently different depending on the electronic states of the three kinds of central metals. In addition, the 1 Pt gel shows unique thermo- and solvatochromism of visible and phosphorescent color in response to a sol-gel phase transition. Furthermore, the 1 Pt gel possesses an attractive ability to inhibit dioxygen quenching of excited triplet states, which increases the phosphorescence quantum yield of this gel. This effect is attributed to the isolation effect of the phosphorescent chelate moiety from the dioxygen-containing solution phase. 相似文献
997.
Fujita M Lee HJ Sugimura T Okuyama T 《Chemical communications (Cambridge, England)》2007,(11):1139-1141
Reaction of 4-acyl-oxy-but-1-enyl-silanes with iodosylbenzene in the presence of BF(3) x OEt(2) gave 4-acyloxy-2-oxobutyl-silane and 3-acyloxy-tetrahydrofuran-2-yl-silane via a 1,3-di-oxan-2-yl cation intermediate, which is generated by participation of the acyloxy group during the electrophilic addition of iodine(III) to the substrate. 相似文献
998.
Fukudome M Yoshikawa K Koga K Yuan DQ Fujita K 《Chemical communications (Cambridge, England)》2007,(30):3157-3159
2(A),3(A)-Alloepithio-2(B)-sulfonyl-beta-cyclodextrin undergoes a tandem reaction to generate an unprecedented C2(A)-S-C2(B)-bridged glucosyl-3(A),6(A)-anhydroglucoside segment. 相似文献
999.
N-dansylcysteines attached on the primary side of beta-cyclodextrin reacted with the saccharide hydroxyl groups in a vector-selective manner, affording the corresponding lactones. The desired topology of the lactones can be efficiently constructed simply by the selection of the proper enantiomer of D/L-cysteines. In comparison with the exo-lactone, the endo-lactone displayed 4 times stronger fluorescence intensity, stronger binding affinity to sodium adamantanecarboxylate, and 15 times larger signal changes in fluorescence intensity upon binding. 相似文献
1000.