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141.
Yuko Mochizuki Shinsuke Inagaki Mayu Suzuki Jun Zhe Min Koichi Inoue Kenichiro Todoroki Toshimasa Toyo'oka 《Journal of separation science》2013,36(12):1883-1889
A novel bromoquinolinium reagent, i.e. 1‐(3‐aminopropyl)‐3‐bromoquinolinium bromide (APBQ), was synthesized for the analysis of carboxylic acids. A simple and practical precolumn derivatization procedure using the APBQ in RP chromatography and MS (HPLC‐MS) has been developed using bile acids and free fatty acids, as the representative carboxylic acids in biological samples. The APBQ efficiently reacted with carboxylic acids at 60°C for 60 min in the presence of N,N‐dicyclohexylcarbodiimide and pyridine as the activation reagents. Because the APBQ possesses a bromine atom in the structure, the identification of a series of carboxylic acids was easily achieved due to the characteristic bromine isotope pattern in the mass spectra. The APBQ also has a quaternary amine structure, thus the positively charged derivatives are predominate for the highly sensitive detection of carboxylic acids. The APBQ was successfully applied to the selective determination of biological carboxylic acids in human plasma. The bile acids (chenodeoxycholic acid and deoxycholic acid) and several saturated (stearic acid and palmitic acid) and unsaturated free fatty acids (oleic acid and linoleic acid) were reasonably determined by HPLC‐MS under the proposed procedure. Based on the results of analyses of human plasma and saliva, the proposed procedure using APBQ seems to be applicable for the qualitative and quantitative analyses of a series of carboxylic acids in biological samples. 相似文献
142.
Yasuhiro Matoba Hiroshi Inoue Jun-Ichi Akagi Takuji Okabayashi Yasutaka Ishii Masaya Ogawa 《合成通讯》2013,43(9):865-873
Applicatims a Mo- and W-based heteropoly acids (HPA) as a catalyst in the oxidation of olefins have extensively been investigated1. However, a patent work is only attempted concerning the evoxidatim of olefins with H202 by HPA2) since the oxirane ring is cleaved because of a strong acidity of HPA itself. Herein, an effective epoxidatim of some allylic alcohols with H202 by a new Mo-species (MPCP), which was prepared from 12-molybdatophosphoric acid (H3PMo12040) and cetylpyridinium chloride (C5H5N (CH2), 15CH3- C1-) under two-phase conditions using chloroform as an organic solvent, is described. 相似文献
143.
Shuichi Oi Mitsutoshi MoroHiroe Fukuhara Takanori KawanishiYoshio Inoue 《Tetrahedron》2003,59(24):4351-4361
The addition of arylstannanes to the carbon-heteroatom double bond in the presence of a catalytic amount of a cationic rhodium complex ([Rh(cod)(MeCN)2]BF4) was examined. The reactions of aldehydes, α-dicarbonyl compounds, and N-substituted aldimines with the arylstannanes gave corresponding alcohols, α-hydroxy carbonyl compounds, and amines, respectively. An arylrhodium complex generated by the transmetalation with the arylstannane was probably the active catalytic species. 相似文献
144.
Masayuki Inoue 《Tetrahedron》2003,59(30):5645-5659
Ladder-shaped polyether natural products show diverse biological activities with extreme potency. As the initial phase of detailed SAR studies of bioactive polyethers, we set out to construct structurally simple mimics. This paper details the divergent synthesis of 6-X-7-6 tetracycles (X=7, 8, or 9) starting from a simple 6-membered ether. Key reactions in the synthesis include (i) the direct formation of an O,S-acetal by the coupling of an alcohol with an α-chlorosulfide, (ii) the construction of a 7-membered ring by radical cyclization, and (iii) cyclization to the 7, 8 or 9-membered ring via a ring-closing metathesis reaction. The neutral reaction conditions of our strategy enable the synthesis of a wide variety of substrates. The results of this study can be applied for the rapid construction of artificial polyether compounds with diversified molecular shapes and sizes. 相似文献
145.
Atsushi TatamiMasayuki Inoue Hisatoshi UeharaMasahiro Hirama 《Tetrahedron letters》2003,44(28):5229-5233
A concise route to the HIJKLM-ring fragment 10 of ciguatoxin (CTX) and 51-hydroxyCTX3C was developed in which oxiranyl anion addition and intramolecular carbonyl olefination were utilized as key transformations. The present procedure requires only 23 steps from the I-ring 5, while 35 steps were employed in a previous synthesis of the corresponding right wing 11 of CTX3C. The high efficiency of the present synthesis ensures a supply of 10 for total synthesis and biomedical applications. 相似文献
146.
Photoelectrochemical decomposition of water on nanocrystalline BiVO4 film electrodes under visible light 总被引:1,自引:0,他引:1
Sayama K Nomura A Zou Z Abe R Abe Y Arakawa H 《Chemical communications (Cambridge, England)》2003,(23):2908-2909
The nanocrystalline BiVO4 film electrode on conducting glass showed an excellent efficiency (IPCE = 29% at 420 nm) for the decomposition of water under visible light. 相似文献
147.
Acid-catalyzed oligomerization of 2-(hydroxymethyl)pyrroles bearing C6F5, 2,6-Cl2C6H3, CF3 and CO2Et groups at beta-positions was examined. The reaction of ethyl pyrrole-3-carboxylates gave a mixture of oligomers and type I isomers of porphyrinogens and hexaphyrinogens were isolated when the other beta-substituents were sufficiently bulky, for example, mesityl, 2,6-Cl2C6H3 and C6F5 groups. On the other hand, the pyrroles having other electron-withdrawing groups afforded porphyrinogens as the only isolable products. 相似文献
148.
Joji Ohshita Takahiro Inoue Taisuke Uemura Toshiyuki Iida Atsutaka Kunai 《Silicon Chemistry》2003,2(3-4):147-149
Compounds having two benzocrown ether units bridged by an organosilicon bridge were prepared by the reactions of lithiated benzocrown derivatives with dichloromono- and disilanes in THF, and the ionochromic effects on their optical properties were studied. Of those, disilanylene-bridged benzocrown ethers exhibited clear ionochromism in the emission spectra and the intensity of the original emission band at about 320 nm decreased and a new broad band centered at 400 nm appeared, when selected alkali or alkali-earth metal ions were added into the acetonitrile solutions. In contrast to this, no significant changes were observed in the UV absorption spectra on addition of the metal ions. 相似文献
149.
Ikuo Ashikawa Mariko Kito Kimiyuki Satoh Hiroyuki Koike Yorinao Inoue Kayoko Saiki Kiyoshi Tsukida Yasushi Koyama 《Photochemistry and photobiology》1987,46(2):269-275
All- trans β-carotene-5,6-epoxide has been found in the thylakoid membranes of spinach and of the cyanobacterium Synechococcus vulcanus Copeland. The epoxide was extracted from the thylakoid membranes with acetone, and was isolated by high-performance liquid chromatography (HPLC). The structure of the epoxide was identified by means of mass, Raman, and electronic absorption spectroscopy. Changes in the amount of the epoxide, as a result of epoxidation and (apparent) de-epoxidation reactions in the membranes, were traced by analysis of extracts on HPLC. In isolated thylakoid membranes, only the epoxidation reaction took place. The reaction was caused by irradiation or by the addition of ferricyanide, suggesting that electron transport reactions in the membranes are involved in the epoxidation. In intact spinach leaves, however, both epoxidation and de-epoxidation took place; the extent of epoxidation correlated with the intensity of light incident on the leaves. The epoxidation and de-epoxidation of all- trans β-carotene are contrasted with those of xanthophylls (in the violaxanthin cycle). 相似文献
150.
N-m-Tolyl-n-phenylhydroxylamine is proposed for the spectrophotometric determination of titanium. The reagent forms a yellow chloroform-soluble complex with titanium in media with a hydrochloric acid concentration of at least 9M. The apparent molar absorptivity at 380 nm is 7.4 x 10(3) 1.mole(-1).cm(-1). The optimum final concentration range is 0-54 mug of titanium in 10 ml of chloroform. The complex contains the metal and reagent in 1:2 ratio. The proposed method has been successfully applied to the determination of titanium in coal, coal fly-ash, pond sediment and asphalt. 相似文献