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41.
The study of γ‐neutrons attenuation and mechanical characteristics of modified concrete are vital and crucial parameters for the construction of civilian radiological, nuclear shielding, and/or shelters. In this work, fifteen samples of ordinary concretes with five different additives; steel fibers, polypropylene, silica fume, and fly ash, with variation of cement percentages, were prepared and used for performing the mechanical and radiation attenuation investigations. The compressive strength, tensile strength, slump test, bulk density, and water permeability were also carried out for the prepared concrete mixes. Collimated coherent beams from 60Co and Pu‐Be fast neutron sources were used to check the radiation penetrability through the syntheized mixed concrete‐additives. Very sensitive and well calibrated gamma‐neutron pulse shape discriminating spectrometer with its electronic componenets and stilbene organic detector and 3′′ × 3′′ NaI scintillation crystal was used to measure the radiation before and after attenuation and transmission. The integrated fast neutron removal macroscopic cross section (Σr) and linear attenuation coefficient of total gamma rays (μ) were calculated for all the analysed concrete mixes. The results of measurements, tests, analyses and calculations are given and explained. The investigated modified concrete mixes show good workability and properties from the view point of mechanical loads and γ‐fast neutrons penetrability and resistance. These results can be used for shielding and sheltering design. 相似文献
42.
Nosrat Mustafa Abed Ebtisam Abdel Aziz Hafez Nadia Sobhy Ibrahim Mohamed Elsaid Mustafa 《Monatshefte für Chemie / Chemical Monthly》1985,116(2):223-228
The behaviour of 3,5-diamino-4-phenylazopyrazole toward a variety of reagents is reported. Several new 3,5-diaminopyrazole derivatives as well as amino derivatives of fused pyrazoles have been prepared.
Untersuchungen an 3,5-Diaminopyrazol-Derivaten
Zusammenfassung Es wird über das Verhalten von 3,5-Diamino-4-phenylazopyrazol gegenüber verschiedenen Agentien berichtet. Es wurden sowohl einige neue 3,5-Diaminooyrazol-Derivate als auch einige Aminoderivate von kondensierten Pyrazolen dargestellt.相似文献
43.
El Sayed H. El Ashry Laila F. Awad H. M. Abdel Hamid Atta I. Atta 《Journal of carbohydrate chemistry》2013,32(7):745-753
Microwave irradiation (MWI) has accelerated the synthesis of S‐(2,3,4,6‐tetra‐O‐acetyl‐β‐D‐glucopyranosyl)thiouronium bromide (2a), whose reaction with 2,3,4,6‐tetra‐O‐acetyl‐α‐D‐glucopyranosyl bromide (1a) in the presence of Et3N afforded stereoselectively the acetylated β,β‐1‐thiotrehalose 4a. Similarly, the respective D‐galactopyranosyl 4b and 2‐acetylamino‐2‐deoxy‐D‐glucopyranosyl 4c analog as well as 4,4′‐di‐O‐(2,3,4,6‐tetra‐O‐acetyl‐β‐D‐galactopyranosyl) 4d and 4,4′‐di‐O‐(2,3,4,6‐tetra‐O‐acetyl‐α‐D‐glucopyranosyl) 4e derivatives of 2,2′,3,3′,6,6′‐hexa‐O‐acetyl β,β‐1‐thiotrehalose were prepared. 相似文献
44.
A. E. Rashad O. A. Heikal A. O. H. El‐Nezhawy F. M. E. Abdel‐Megeid 《Heteroatom Chemistry》2005,16(3):226-234
Several derivatives containing the thieno[2,3‐d]pyrimidine system were prepared starting from 2‐amino‐4,5‐dihydronaphtho[2,1‐b]thiophene‐1‐carbonitrile ( 1 ). In particular, the synthesis and structure characterization of 8,9‐dihydronaphtho‐ [1′,2′:4,5]thieno[3,2‐e][1,2,4]triazolo[4,3‐c]pyrimidine derivatives 13–16 and their isomerization to 8,9‐dihydronaphtho[1′,2′:4,5]thieno[3,2‐e][1,2,4]‐triazolo[1,5‐c]pyrimidine derivatives 17–20 under different suitable reaction conditions were reported and verified with X‐ray analysis. Moreover, compounds 13, 14 and 22 were tested as potential anti‐inflammatory agents and derivative 14 showed potent activity in carrageenan test. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:226–234, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20114 相似文献
45.
Adel A.‐H. Abdel‐Rahman Wael A. El‐Sayed El‐Sayed G. Zaki Asem A. Mohamed Ahmed A. Fadda 《Journal of heterocyclic chemistry》2012,49(1):93-101
A number of new [(pyrazol‐4‐yl)methylene]hydrazono‐2,3‐dihydrothiazole derivatives, their sugar hydrazones and N‐glycosides were synthesized. Furthermore, N‐substituted oxygenated alkyl and hydroxyl derivatives and 1,3,4,‐oxadiazoline acyclic nucleoside analogs were prepared. The newly synthesized compounds were tested for their antimicrobial activities and showed moderate to high inhibition activities. J. Heterocyclic Chem., (2012). 相似文献
46.
Wael A. El‐Sayed Omar M. Ali Merfat S. Faheem Ibrahim F. Zied Adel A.‐H. Abdel‐Rahman 《Journal of heterocyclic chemistry》2012,49(3):607-612
New [1,2,4‐oxadiazolyl]methyl‐3H‐[1,2,3]triazolo[4,5‐d]pyrimidin derivatives were synthesized starting from N′‐Hydroxy‐1‐naphthimidamide. The N‐substituted acyclic nucleoside analogs as well as the substituted glycosides were also prepared by reaction with the corresponding reagents. The antimicrobial results indicated that most of the tested compounds exhibited moderate to high antimicrobial activity whereas few compounds were found to exhibit little or no activity against the tested microorganisms. 相似文献
47.
Balkis Al‐Saleh Morsy Ahmed El‐Apasery Rasha Safwat Abdel‐Aziz Mohamed Hilmy Elnagdi 《Journal of heterocyclic chemistry》2005,42(4):563-566
The 3‐anilinoenones 3a,b were prepared from the corresponding 3‐dimemyl‐aminopropenones. The reactivity of 3a,b towards a variety of carbon and nitrogen nucleophiles as well as naphthoquinones is reported. 相似文献
48.
Ali A. Abdel Hafez Ibrahim M. A. Awad Khairy M. Hassan 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):219-225
Abstract Some new derivatives containing both 8-hydroxyquinoline and sulphonylamino β-lactams and thiazolidinones have been prepared. These compounds were synthesized from the corresponding 8-hydroxyquinoline sulphonylhydrazide (1) by converting it to hydrazones (2). The latter hydrazones (2) were easily transformed to β-lactams (3) and thiazolidinones (4) by cyclocondensation reaction with chloroacetyl chloride and/or mercaptoacetic acid. Some metal chelates with Fe3+. Co2++, Ni2+, Cu2+ and Cd2+ have been prepared for some of the compounds and screened in vitro for their biological activity. 相似文献
49.
Lobna Abdel‐Mohsen Ebaid Nassr 《国际化学动力学杂志》2010,42(6):372-379
Kinetics of aquation of some Fe(II) Schiff base amino acid complexes was followed spectrophotometrically. The Schiff base ligands were derived from salicylaldehyde and isoleucine, leucine, serine, methionine, tryptophan, or histidine. The reaction was studied in aqueous media, aqua–propanol mixtures, and in the presence of different concentrations of KBr. Moreover, the activation parameters were calculated and discussed for structures and other physical properties observed. The reaction was acid catalyzed and the general rate equation was suggested as follows: rate = kobs [complex], where kobs = k2 [H+]. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 372–379, 2010 相似文献
50.
Anas M. Abdel Rahman Andreas L. Lopata Robyn E. O'Hehir John J. Robinson Joseph H. Banoub Robert J. Helleur 《Journal of mass spectrometry : JMS》2010,45(4):372-381
The protein tropomyosin (TM) is a known major allergen present in shellfish causing frequent food allergies. TM is also an occupational allergen generated in the working environment of snow crab (Chionoecetes opilio) processing plants. The TM protein was purified from both claw and leg meats of snow crab and analyzed by electrospray ionization and matrix‐assisted laser desorption/ionization (MALDI) using hybrid quadruple time‐of‐flight tandem mass spectrometry (QqToF‐MS). The native polypeptide molecular weight of TM was determined to be 32 733 Da. The protein was further characterized using the ‘bottom‐up’ MS approach. A peptide mass fingerprinting was obtained by two different enzymatic digestions and de novo sequencing of the most abundant peptides performed. Any post‐translational modifications were identified by searching their calculated and predicted molecular weights in precursor ion spectra. The immunological reactivity of snow crab extract was evaluated using specific antibodies and allergenic reactivity assessed with serum of allergic patients. Subsequently, a signature peptide for TM was identified and evaluated in terms of identity and homology using the basic local alignment search tool (BLAST). The identification of a signature peptide for the allergen TM using MALDI‐QqToF‐MS will be critical for the sensitive and specific quantification of this highly allergenic protein in the work place. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献