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821.
Prof. Nobuhiro Yanai Prof. Nobuo Kimizuka 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(26):10336-10348
The addition of stimuli-responsiveness to anti-Stokes emission provides a unique platform for biosensing and chemosensing. Particularly, stimuli-responsive photon upconversion based on triplet–triplet annihilation (TTA-UC) is promising due to its occurrence at low excitation intensity with high efficiency. This Minireview summarizes the recent developments of TTA-UC switching by external stimuli such as temperature, oxygen, chemicals, light, electric field, and mechanical force. For the systematic understanding of the underlying general mechanisms, the switching mechanisms are categorized into four types: 1) aggregation-induced UC; 2) assembly-induced air-stable UC; 3) diffusion-controlled UC; and 4) energy-transfer-controlled UC. The development of stimuli-responsive smart TTA-UC systems would enable sensing with unprecedented sensitivity and selectivity, and expand the scope of TTA-UC photochemistry by combination with supramolecular chemistry, materials chemistry, mechanochemistry, and biochemistry. 相似文献
822.
This paper analyzes strategic store openings in a situation in which firms can open multiple stores depending on the financial constraints of the firm. Specifically, given any upper limit of the number of store openings that two potentially symmetric firms can open, they sequentially determine the number of store openings, including their locations, to maximize their profits. As a result of our analysis in a microeconomic framework, we show that the equilibrium strategy can be wholly classified into only two following opposite strategies according to the level of their financial constraints involved. When firms can afford to invest significant amounts of money in the market, the leader chooses “segmentation strategy,” in which a part of the market can be monopolized by opening a chain of multiple stores and deterring the follower’s entry. In contrast, when the leader has a severe financial constraint so that it can only monopolize less than half of the market, the leader chooses “minimum differentiation strategy,” where firms open each of their stores at exactly the same point as the rival’s. Under this strategy, the leader necessarily captures just half of the market. Furthermore, we show that regardless of potential symmetry between firms, both first and second mover advantages in terms of profit can occur in the equilibrium. 相似文献
823.
Polymeric analogs of tetramethylurea were prepared by free-radical polymerization of N,N,N'-trimethyl-N'-p-vinylbenzylurea and copolym-erization of this monomer with styrene. These polymers are soluble in toluene and have the ability to extract alkali metal ions such as lithium, sodium, and potassium. Moreover, these polymers act as phase-transfer catalysts for typical S N 2 reactions, although the monomeric analogs tetramethylurea and N,N,N'-trimethyl-N'-benzylurea do not. A plausible mechanism for these catalytic reactions is proposed. 相似文献
824.
M14-2 is a cellulase hyperproducer derived from Trichderma recesei QM 6a, but with a growth rate lower than that of the original strain. When M14-2 was autopolyploidized followed by haploidization
and selection, the strain with both a higher cellulase productivity per mycelia and a higher growth rate could be obtained
as M14-2B. This strain seemed to be constructed using gene sources amplified by additional autopolyploidization. 相似文献
825.
Yasunori Muranishi Yue Wang Mamiko Odoko Nobuo Okabe 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(6):m307-m310
In the three title complexes, namely (2,2′‐biquinoline‐κ2N,N′)dichloropalladium(II), [PdCl2(C18H12N2)], (I), and the corresponding copper(II), [CuCl2(C18H12N2)], (II), and zinc(II) complexes, [ZnCl2(C18H12N2)], (III), each metal atom is four‐coordinate and bonded by two N atoms of a 2,2′‐biquinoline molecule and two Cl atoms. The PdII atom has a distorted cis‐square‐planar coordination geometry, whereas the CuII and ZnII atoms both have a distorted tetrahedral geometry. The dihedral angles between the N—M—N and Cl—M—Cl planes are 14.53 (13), 65.42 (15) and 85.19 (9)° for (I), (II) and (III), respectively. The structure of (II) has twofold imposed symmetry. 相似文献
826.
The title compounds, bis(pyridine‐2,6‐dicarboxylato‐N,O,O′)copper(II) monohydrate, [Cu(C7H4NO4)2]·H2O, andbis(pyridine‐2,6‐dicarboxylato‐N,O,O′)zinc(II) trihydrate, [Zn(C7H4NO4)2]·3H2O, have distorted octahedral geometries about the metal centres. Both metal ions are bonded to four O atoms and two pyridyl‐N atoms from the two terdentate ligand molecules, which are nearly perpendicular to each other. The copper(II) complex has twofold crystallographic symmetry and contains two different ligand molecules, one of which is neutral and another doubly ionized. In contrast, the zinc(II) complex contains two identical singly ionized ligand molecules. Both crystal structures are stabilized by O—H?O intermolecular hydrogen bonds between the complex and the water molecules. 相似文献
827.
Nobuo Okabe Michihiro Tsujita 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):1418-1419
In the title compound, [Li(C5H3N4O2)(H2O)2]n, the coordinate geometry about the Li+ ion is distorted tetrahedral and the Li+ ion is bonded to N and O atoms of adjacent ligand molecules forming an infinite polymeric chain with Li—O and Li—N bond lengths of 1.901 (5) and 2.043 (6) Å, respectively. Tetrahedral coordination at the Li+ ion is completed by two cis water molecules [Li—O 1.985 (6) and 1.946 (6) Å]. The crystal structure is stabilized both by the polymeric structure and by a hydrogen‐bond network involving N—H?O, O—H?O and O—H?N hydrogen bonds. 相似文献
828.
Nobuo Sakairi Toshio Yoneta Md. Dalilur Rahman Yoshiharu Ishido 《Journal of carbohydrate chemistry》2013,32(1):51-65
Abstract Hydrazinolyses of hexa-0-benzoyl-tetra-N-benzyloxycarbonyl-and N-ethoxycarbonylkanamycin A were performed and found to be sufficiently regioselective to give the corresponding 2′-hydroxyl derivatives in good yields under controlled conditions. The products were converted into the corresponding 2′-triflates, which were then subjected to nucleophilic substitution reactions with sodium benzenethioxide, sodium benzoate, and sodium azide to give the corresponding d-mannopyranosyl derivatives in good yields. Deprotection of the phenylthio (10) and azido (12) derivatives, and hydrogenolysis, gave 2′-deoxykankmycin A and 2′-epi-kanamycin B, respectively. Moreover, deprotection of the benzoyl compound 11 gave 2′-epi-kanamycin A. 相似文献
829.
Hitoshi Tamiaki Nobuo Kosaka Yusuke Kinoshita 《Research on Chemical Intermediates》2013,39(1):221-232
A cyclic chlorophyll hetero-dyad 1-H2H2, prepared by double ester linking of two structurally different pyropheophorbide-a moieties through 3-CH2OCO-132′ and 172-COOCH2-3′, was metallated with zinc and copper to give mono and di-metallated complexes 1-MH2 or 1-H2M and 1-MM. The metallation proceeded stepwise and regioselectively, with predominant synthesis of one of the two mono-metallated complexes 1-MH2 as intermediate. The di-zinc complex produced, 1-ZnZn, was demetallated exclusively via the same mono-zinc complex 1-ZnH2 as was the major intermediate during metallation. Visible and/or circular dichroism spectra of 1-H2H2, 1-MH2, 1-H2M, and 1-MM (M = Ni, Cu, or Zn) were measured in organic solvents. Intramolecular interaction of chlorin chromophores is discussed and compared with that of the corresponding monomeric species. 相似文献
830.
Fengfu Fu Nobuo Shinohaya Mitsuo Ito Xueqin Xu Mincong Shen Liangjun Xu 《Particuology》2008,6(3):218-222
The mass concentration and size distribution of aerosols in Tokaimura were investigated using a high-volume and a low-volume Andersen sampler. A difference was found using the two samplers: the concentration of total aerosols determined with the high-volume sampler is smaller than that of the low-volume sampler by 70-90% throughout the year. Compared to the high-volume sampler, low-volume sampler gave lower concentration for aerosols 〉7 μm, higher concentration for aerosols of 3.3-7.0 μm and 〈 1.1 μm, though similar results for aerosols of 1.1-3.3 μm. The low-volume sampler was found to have better separation efficiency and higher accuracy. 相似文献