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991.
Tainá Olivieri Chaves Akira Iwahara Luiz Tauhata Eduarda Alexandre Rezende Amanda Ribeiro Correia Estela Maria de Oliveira 《Journal of Radioanalytical and Nuclear Chemistry》2012,293(1):211-216
The radionuclide 131I has been increasingly used in nuclear medicine therapy procedures. Nowadays, the 131I source administered to the patient is manufactured in two different geometries: solution and capsules. The purpose of this study is the accurate measurement of the activity present in a 131I capsule without destroys it. The methodology to determine the capsules activity is to obtain the calibration factor of an IG12 secondary standard activity measurement system based on the IG12 well-type ionization chamber set up at Brazilian national metrology laboratory for ionizing radiation (LNMRI) of institute of radiation protection and dosimetry (IRD).The result obtained, 6.4670?±?0.0381?×?10?18?A?Bq?1, is quite similar to the calibration factor of the 131I solution contained in the standard ampoule geometry, 6.4515?±?0.0368?×?10?18?A?Bq?1. After obtaining the calibration factor it was used to measure 131I therapy capsules in order to check the performance of radionuclide calibrators of some Brazilian nuclear medicine centers. 相似文献
992.
993.
The polymerization of methyl methacrylate and acrylonitrile is shown to occur by an anionic mechanism initiated by a 1:1 complex between triethyl aluminum and hexamethyl phosphoric acid triamide at a relatively high temperature. This complex can also initiate the radical polymerization of vinyl monomers at relatively low temperatures. A tentative initiation mechanism is presented. 相似文献
994.
The reactions of aryl Grignard reagents with p- and m-bromochlorobenzenes catalyzed by non-ligated NiCl2 give selectively chlorobiphenyl derivatives. By the stepwise reaction, an unsymmetrical terphenyl was synthesized in a good yield. 相似文献
995.
Shigeru Kubota Toshimoto Moriwaki Torahiko Ando Akira Fukami 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):1407-1422
The monomers were derived from pyromellitic dianhydride and α-(2-nitrophenyl)ethanol, which was prepared by selective reduction of 2-nitroacetophenone. Polyimide precursors were synthesized by an interfacial polycondensation technique. Their thermal properties in nitrogen were studied by dynamic thermogravimetry. The photore-arrangement of 2-nitrobenzyl ester having a methyl group at the α-position compared to that of the unsubstituted ester was investigated by infrared spectrophotometry. The polymers obtained in this study gave a high proportion of photorearrangement to show high sensitivity. The exposed areas dissolved in 2% aqueous KOH, forming high resolution patterns because they did not swell during the developing process. 相似文献
996.
Akira Hasegawa Minoru Morita Hideharu Ishida Makoto Kiso 《Journal of carbohydrate chemistry》2013,32(4):579-588
Abstract Various types of the O-protected derivatives and the 9-bromo analogs of methyl [2-(trimethylsilyl)ethyl 5-acetamido-3,5-dideoxy-D-glycero-α-D-galacto-2-nonulopyranosid]onate were synthesized from methyl [2-(trimethyl-silyl)ethyl 5-acetamido-4,7-di-O-acetyl-3,5-dideoxy-D-glycero-α-D-galacto-2-nonulopyranosid]onate (1) or methyl [2-(trimethylsilyl)ethyl 5-acetamido-8,9-di-O-isopropylidene-D-glycero-α-D-galacto-2-nonulopyranosid]onate (3). 相似文献
997.
Abstract After the first report of the synthesis and deblocking of some 2-(trimethylsilyl)ethyl (SE) glycosides by Lipshutz and coworkers,1 a few more papers appeared describing facile deprotection of the SE group in such glycosides or some of their derivatives.2 We have employed the SE glycosides of D-galactose,3a,b D-glucose, D-galacto-samine, D-glucosamine,3c D-lactose,3d and neuraminic acid3e very extensively in our work on oligosaccharide synthesis. We have found that the SE group possesses a useful combination of properties, namely, stability over a wide range of pH which makes many experimental manipulations possible, and easy removability under certain specific but mild conditions. 相似文献
998.
999.
Eiji Tanahashi Katsutoshi Murase Mika Shibuya Yumie Igarashi Hideharu Ishida Akira Hasegawa 《Journal of carbohydrate chemistry》2013,32(6):831-858
Abstract A systematic synthesis of sulfatide (I) and novel sulfatide analogs (II-VI) carrying 2-(tetradecyl)hexadecyl group as a ceramide substitute is described. The 3-O-, 4-O- and 3,4-di-O-levulinoyl derivatives of galactopyranosyl trichloroacetimidates (1, 12, and 13) were coupled with (2S,3R,4E)-3-O-acetyl-2-octadecanamido-4-octadecene-1,3-diol or 2-(tetradecyl)hexadecan-1-ol. The resulting glycolipids (2, 4, 14, and 15) were each transformed, by selective removal of the levulinoyl group(s), and successive sulfation and de-O-acylation, into the 3-sulfates (I, II), 4-sulfate (III), and 3,4-disulfate (IV). The 6-sulfate (V) was prepared from 2-(tetradecyl)hexadecyl β-D-galactopyranoside (21) via the 6-O-t-butyldimethylsilyl derivative, while the 3′-sulfate of 2-(tetradecyl)hexadecyl β-D-lactoside (VI) was synthesized from 2-(trimethylsilyl)ethyl 3′-O-benzyl-β-D-lactoside (26). The structures of the sulfated glycolipids (I-VI) were characterized by ion-spray MS, MS/MS, and 1H NMR spectrometry. 相似文献
1000.