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991.
Masashi Kijima Kazuaki Hiroki Hideki Shirakawa 《Macromolecular rapid communications》2002,23(15):901-904
A novel conjugated polymer with allene moieties in the polymer main chain, poly(4,4′‐biphenylylene‐1,3‐diphenylpropadien‐1,3‐ylene), was synthesized from 1,3‐bis(4‐bromophenyl)‐1,3‐diphenylpropadiene by dehalogenative polycondensation using Ni(cod)2. The polymer shows good solubility in common organic solvents, good processability for making thin films, intense blue fluorescence in solution and acid sensitivity resulting in coloration. The conductivity increased by an order of 104 upon exposure to trifluoroacetic acid vapor. 相似文献
992.
993.
994.
Kaname Hashizaki Chika Itoh Hideki Sakai Shoko Yokoyama Hiroyuki Taguchi Yoshihiro Saito Naotake Ogawa Masahiko Abe 《Colloids and surfaces. B, Biointerfaces》2000,17(4):305-282
The differential scanning calorimetry (DSC) and the freeze-fracture electron microscopy of dipalmitoyl phosphatidylcholine (DPPC) liposomes containing distearoyl-N-monomethoxy poly(ethylene glycol)-succinyl-phosphatidylethanolamines (PEG-DSPE) were carried out. The DSC peak of DPPC liposomes containing PEG-DSPE had a shoulder. The main phase transition temperature of DPPC bilayer membranes containing PEG-DSPE whose molecular weight of PEG is less than 3000 was slightly shifted to a higher temperature, while that containing PEG-DSPE whose molecular weight of PEG is more than 5000 was slightly shifted to a lower temperature. The electron micrographs of freeze-fracture replicas of DPPC liposomes containing PEG-DSPE quenched from 37±2°C exhibited banded and planar textures, suggesting the lateral phase separation in the bilayer membranes. 相似文献
995.
Daisuke Hashizume Naoki Takashima Takashi Oikawa Hideki Ishii Haruki Niwa Fujiko Iwasaki 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(7):827-829
The title compounds, 3a,9a‐trans‐9,9a‐trans‐4,4‐dimethyl‐9‐phenyl‐2,3,3a,4,9,9a‐hexahydrobenzo[f]indene, C21H24, (I), and 3a,4‐trans‐3a,9a‐cis‐9,9a‐trans‐4‐methoxy‐9‐phenyl‐2,3,3a,4,9,9a‐hexahydrobenzo[f]indene, C20H22O, (II), are products of the photoinduced electron‐transfer reaction of 1,1‐diphenyl‐1,n‐alkadienes. The molecular structures are in good agreement with those proposed from the reaction mechanisms. The central rings of the fused systems of both compounds take chair and boat conformations in (I) and (II), respectively. There are no remarkable short contacts shorter than the sum of the van der Waals radii in the crystals, but some weak C—H?π interactions are found. 相似文献
996.
Low coherence interferometry can provide simultaneous measurement of refractive index n and thickness t of a transparent plate, as reported recently by some research groups. Precise measurement of n and t is impossible unless chromatic dispersion of index is taken into account. We then proposed and demonstrated a unique technique for simultaneous measurement of phase index np, group index ng and thickness t using a special sample holder. This paper describes a novel technique for simultaneous measurement of np, ng and t using an approximate expression of the chromatic dispersion in terms of np. The approximate expression of chromatic dispersion does not require use of the special sample holder, and np, ng and t are determined from two measurable quantities with an accuracy of 0.3% or less, for the sample thickness was around 1 mm. In addition, it is possible to shorten the measurement time compared with the above method. 相似文献
997.
Ikuma Shimizu Dr. Yuma Morimoto Dr. Gunasekaran Velmurugan Dr. Tulika Gupta Dr. Sayantan Paria Dr. Takehiro Ohta Dr. Hideki Sugimoto Prof. Takashi Ogura Prof. Peter Comba Prof. Shinobu Itoh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(47):11157-11165
A tetrahedral CuII alkylperoxido complex [CuII(TMG3tach)(OOCm)]+ ( 1OOCm ) (TMG3tach={2,2′,2′′-[(1s,3s,5s)-cyclohexane-1,3,5-triyl]tris-(1,1,3,3-tetramethyl guanidine)}, OOCm=cumyl peroxide) is prepared and characterized by UV/Vis, cold-spray ionization mass spectroscopy (CSI-MS), resonance Raman, and EPR spectroscopic methods. Product analysis of the self-decomposition reaction of 1OOCm in acetonitrile (MeCN) indicates that the reaction involves O−O bond homolytic cleavage of the peroxide moiety with concomitant C−H bond activation of the solvent molecule. When an external substrate such as 1,4-cyclohexadiene (CHD) is added, the O−O bond homolysis leads to C−H activation of the substrate. Furthermore, the reaction of 1OOCm with 2,6-di-tert-butylphenol derivatives produces the corresponding phenoxyl radical species (ArO.) together with a CuI complex through a concerted proton-electron transfer (CPET) mechanism. Details of the reaction mechanisms are explored by DFT calculations. 相似文献
998.
Dr. Yoshinao Shinozaki Dr. Chiasa Uragami Prof. Dr. Hideki Hashimoto Prof. Dr. Hitoshi Tamiaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(41):8897-8906
Accurately mimicking structure and function of natural chlorophyll (Chl) assemblies is very challenging. Herein, we report the synthesis of a fullerene-appended Chl dimer being capable of intramolecular photoinduced charge separation (CS) with a unique structure reminiscent of reaction centers (RCs) in phototrophs. Structural analyses revealed that the Chl dimer adopts a bird-like structure in which two Chl components overlapped partially with one of the four pyrrole rings in a Chl ring similar to in a Chl pair in the natural RC complexes. A comparative study including voltammetry and spectrometric analyses using the Chl dimer and its corresponding monomer with and without a fullerene moiety was performed to gain insight into the effect of Chl pairing on (photo)redox properties. Our results suggest that the present dimer motif that closely resemble the Chl pair in natural RCs lead to more facile oxidation and lower energy of the CS state of the Chl dimer than those of the Chl monomer, resulting in its photoredox behavior different from that of the monomer Chl. 相似文献
999.
Kazuhiro Haraguchi Hiroki Kumamoto Kiju Konno Hideki Yagi Yutaka Tatano Yuki Odanaka Satoko Shimbara Matsubayashi Robert Snoeck Graciela Andrei 《Tetrahedron》2019,75(33):4542-4555
4′-Azido- (7), 4′-C-fluoromethyl- (8) 4′-C-ethynyl- (9) and 4′-C-cyano- (10) 2′-deoxy-4′-thiocytidines have been synthesized. In this study, it was found that the isolated yield of 4′-thiouracil nucleoside 13 in a Lewis acid-promoted Vorbrüggen-type glycosidation utilizing 12 was better than that of the electrophilic glycosidation reaction between silylated uracil and 11. This improved result prompted us to perform the glycosidation utilizing 36 and 43 for the synthesis of 37 and 44. Introduction of the azido group was carried out by nucleophilic substitution in the 4′-benzoyloxy derivative 22a. On the other hand, 9 and 10 were synthesized by way of the chemical manipulation of the hydroxymethyl group at the 4′-position of 46.Evaluation of the antineoplastic activity of 2 and 7–10 against human B-cell (CCRF-SB) and T-cell leukemia (Molt-4) cell lines revealed that 4′-azido- (7) and 4′-C-fluoromethyl- (8) derivatives exhibited cytotoxic activity whereas no cytotoxicity was observed in the 4′-C-ethynyl- (9) and 4′-C-cyano- (10) derivatives as well as the parent compound 2. Compound 7 was also found to possess promising antiviral activity against VZV and HSV-1 without any cytotoxity against HEL host cells. It is noteworthy that 7 exhibited potent inhibitory activities against the thymidine kinase-deficient (TK?) mutant of VZV and HSV-1. 相似文献
1000.