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81.
Receptors and , incorporating two heterocyclic recognition units as well as oxime- or hydroxymethyl-based hydrogen-bonding sites, were prepared, and their binding properties toward neutral sugars were determined. The design of these receptors was inspired by the binding motifs observed in the crystal structure of protein-carbohydrate complexes. The receptors and are able to recognize both mono- and disaccharides, with a strong preference for the disaccharides. Both hydrogen-bonding and interactions of the sugar CH's with the phenyl rings of the receptor contribute to the stabilisation of the receptor-sugar complexes. Molecular modeling calculations, synthesis and binding studies are described. 相似文献
82.
Arno Behr Thomas Beckmann Pierre Schwach 《Journal of organometallic chemistry》2008,693(18):3097-3102
Two different routes to acetoxyoctadiene are presented. The first one uses the well-known telomerisation of butadiene with acetic acid operating in a multiphase semi-batch mode. The second reaction involves the cleavage of acetic anhydride, hydrogen transfer via ketene formation and thus a telomerisation as well. 相似文献
83.
84.
Kambiz Farbod Mani Diba Tatiana Zinkevich Stephan Schmidt Matthew J. Harrington Arno P. M. Kentgens Sander C. G. Leeuwenburgh 《Macromolecular bioscience》2016,16(5):717-729
Gelatin nanoparticles can be tuned with respect to their drug loading efficiency, degradation rate, and release kinetics, which renders these drug carriers highly suitable for a wide variety of biomedical applications. The ease of functionalization has rendered gelatin an interesting candidate material to introduce specific motifs for selective targeting to specific organs, but gelatin nanoparticles have not yet been modified to increase their affinity to mineralized tissue. By means of conjugating bone‐targeting alendronate to biocompatible gelatin nanoparticles, a simple method is developed for the preparation of gelatin nanoparticles which exhibit strong affinity to mineralized surfaces. It has been shown that the degree of alendronate functionalization can be tuned by controlling the glutaraldehyde crosslinking density, the molar ratio between alendronate and glutaraldehyde, as well as the pH of the conjugation reaction. Moreover, it has been shown that the affinity of gelatin nanoparticles to calcium phosphate increases considerably upon functionalization with alendronate. In summary, gelatin nanoparticles have been developed, which exhibit great potential for use in bone‐specific drug delivery and regenerative medicine.
85.
Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) of noncovalent protein complexes is difficult, due to the disruptive nature of processes occurring during MALDI sample preparation and ion formation. Sometimes the observation of intact noncovalent protein complexes with MALDI is only possible if data are acquired from the first laser shot fired at a fresh sample; this is called the 'first shot phenomenon'. To study the origin of the first shot phenomenon, we used MALDI-MS and confocal laser scanning microscopy (CLSM) to examine typical MALDI sample preparations with embedded protein complexes, labeled with fluorophores. Fluorescence energy transfer techniques allowed the differentiation between intact and dissociated protein complexes with CLSM. In cases where a first shot behavior was observed by MALDI-MS, it was found to be accompanied by localization of protein complexes at the exterior of the sample crystals. Segregation of the large protein complexes to the exterior and dissociation of the complexes in the crystal interior during sample crystallization can rationalize this observation. 相似文献
86.
If an open interval I contains a k -fold root α of a real polynomial f, then, after transforming I to (0,∞), Descartes’ Rule of Signs counts exactly k roots of f in I, provided I is such that Descartes’ Rule counts no roots of the kth derivative of f. We give a simple proof using the Bernstein basis. 相似文献
87.
Comparison is made between the preparation of trans-1,2-cyclohexanediol in standard glassware (conventional batch production) and in a microreactor (continuous flow production). The reaction sequence involved two exothermic steps where the standard procedure demands slow reagent addition and careful temperature control. In the microreactor, the reaction could be carried out safely with up to 3 times higher reagent concentration. Synthetic benefits were a faster reaction rate and a higher purity product free of colored impurities (a feature of the batch procedure). 相似文献
88.
Representatives of a new series of acyclic oxime-based receptors were prepared and their binding properties toward neutral sugar molecules studied. 1H NMR and fluorescence titrations revealed that receptors 2a and 2b, incorporating suitable positioned amine and oxime moieties, are able to form strong 1:1 complexes (Ka1 approximately 10(5) M-1) with dodecyl alpha- and beta-maltoside in chloroform solutions. Furthermore, the binding studies with beta-glucopyranoside indicated the formation of complexes with 1:1 and 1:2 receptor-monosaccharide binding stoichiometry (with overall binding constant beta2 approximately 10(5) M-2). Both hydrogen bonding and interactions of the sugar CH's with the phenyl rings of the receptor contribute to the stabilization of the receptor-sugar complexes. Molecular modeling calculations, synthesis, and binding studies are described. 相似文献
89.
90.
Roland Lang Arno Schrwerth Kurt Polborn Walter Ponikwar Wolfgang Beck Theodor Severin Kay Severin 《无机化学与普通化学杂志》1999,625(8):1384-1390
Organometallic Compounds with N -substituted 3-Hydroxy-2-methyl-4-pyridone Ligands: square planar Rhodium(I), Iridium(I), and Palladium(II) Complexes Reactions of [(OC)2MCl]2 (M = Rh, Ir) or [(cod)RhCl]2 with the anions of N-Aryl or N-Alkyl substituted 3-hydroxy-2-methyl-4-pyridones (O–O′) yield complexes of the general formula [L2M(O–O′)]. Compounds of this type are also available from reactions of [(OC)2Rh(acac)] with the corresponding neutral ligands. Substitution of one carbonyl-ligand of the N-phenyl complex [(OC)2Rh(C12H10NO2)] ( 2 ) with cyclooctene affords [(OC)(C8H14)Rh(C12H10NO2)] ( 8 ). The palladium complexes [(R3P)Pd(O–O′)Cl] (R = Et, Bu), [(C6H4CH2NMe2) · Pd(O–O′)] and [(Et3P)2Pd(O–O′)]BF4 ( 9 – 12 ) were synthesized from [(R3P)PdCl2]2, [(C6H4CH2NMe2)PdCl]2 or [(Et3P)PdCl2]. The structures of the N-methyl compounds [(OC)2Rh(C7H8NO2)] ( 1 ) and [(Ph3P)Pd(C7H8NO2)Cl] ( 9 ) were determined by single crystal X-ray diffraction. 相似文献