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991.
TSIM Karl Wah-keung 《高等学校化学研究》2010,(2)
Flavonoids exhibit a wide range of biological activities including anti-inflammatory activity,while some 1,3-benzoxazine derivatives show anti-inflammatory activity.In order to explore the novel anti-inflammatory agents,based on the principles of bioisosterism and hybridization,ten novel chromeno[8,7-e][1,3]oxazin-4-ones were synthesized and characterized with IR,1H NMR,MS and elemental analyses.The anti-inflammatory activities of the target compounds were evaluated via the croton oil-induced ear oedema tes... 相似文献
992.
Aromatic cycloimmonium ylides underwent smooth cyclization with electron deficient alkynes in presence of anhydrous K2CO3 in DMF solvent at room temperature to afford substituted indolizines. Ylides have also undergone expected cyclization with ethyl cyanoformate to produce imidazo[1,2-a]pyridines. The structures of these newly synthesized compounds have been confirmed by spectroscopic techniques and X-ray diffraction studies. 相似文献
993.
Cucurbituril‐mediated immobilization of fluorescent proteins on supramolecular biomaterials
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Olga J. G. M. Goor Ralph P. G. Bosmans Luc Brunsveld Patricia Y. W. Dankers 《Journal of polymer science. Part A, Polymer chemistry》2017,55(21):3607-3616
The reversible introduction of functionality at material surfaces is of interest for the development of functional biomaterials. In particular, the use of supramolecular immobilization strategies facilitates mild reaction and processing conditions, as compared to other covalent analogues. Here, the engineering of multicomponent supramolecular materials, beyond the use of a single supramolecular entity is proposed. Cucurbit[8]uril (Q8) mediated host–guest chemistry is combined with hydrogen bonding supramolecular 2‐ureido‐4‐pyrimidinone (UPy)‐based materials. The modular incorporation of a UPy‐additive that presents one guest to incorporate into the Q8 host allows for selective supramolecular functionalization at the water–polymer material interface. Supramolecular ternary complex formation at the material surface was studied by X‐ray photoelectron spectroscopy, which as a result of large overlap in atomic composition of the different components showed minor changes is surface composition upon complex formation. Surface MALDI‐ToF MS measurements revealed useful insights in the formation of complexes. Protein immobilization was monitored using both fluorescence spectroscopy and quartz crystal microbalance with dissipation monitoring, which successfully demonstrated ternary complex formation. Although proteins could selectively be immobilized onto the surfaces, control of the system's stability remains a challenge as a result of the dynamicity of the host–guest assembly. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3607–3616 相似文献
994.
《Mendeleev Communications》2021,31(6):859-861
Various N-(pyridin-2-yl)acrylamides bearing 4H-chromene fragment were synthesized via the condensation of 4H-chromene-3-carbaldehydes and their fused analogues with 2H-pyrido[1,2-a]pyrimidine-2,4(3H)-diones employing NH4OAc/AcOH system. Possible mechanism of this hetero- domino reaction involves the consecutive Knoevenagel condensation, oxa-6v-electrocyclization, aza-6v-electrocyclic ring-opening, nucleophilic addition, retro-Alder-ene reaction and oxa-6v-electrocyclic ring-disclosure. 相似文献
995.
A facile synthesis of tri and tetracyclic frameworks containing [1,8]naphthyridin-2-one skeleton from the Baylis-Hillman alcohols via the Johnson-Claisen rearrangement, followed by the treatment with Fe/AcOH in simple one-pot multi-step process is described. 相似文献
996.
《Journal of Coordination Chemistry》2012,65(3):467-478
Abstract The chemical and direct electrochemical syntheses of copper, cobalt, nickel and zinc chelates of 2-[N-tosylamine)benzaldoxime (L1H2) and 2-[N-tosylamine)benzal-O-methyloxime (L2H) are reported. On the basis of the elemental analyse IR and EPR spectra and magnetic properties, dimeric structures ML are suggested from L1H2 under the conditions of the chemical synthesis, while electrosynthesis leads to the monomeric complexes M(L1H)2. Using L2H as a ligand, only the chelates ML2 2 are formed, regardless of the method of synthesis. The copper dimers CuL1 have antiferromagnetic properties, while the chelates M(L1H)2 and ML2 have normal magnetic moments. In agreement with the magnetic properties and literature data on structures of four-coordinate complexes a tetrahedral structure is assigned. 相似文献
997.
Sahar Al Akoum-Ebrik Mohamed Ansar Rahima Mouhoub Claude Vaccher Marie-Pierre Vaccher Nathalie Flouquet 《光谱学快报》2013,46(5):925-944
The enantiomeric composition and absolute configuration of 4-Amino-3-(benzo[b]furan-2-yl)-Butanoic Acids and of 4-Amino-3-(thien-2-yl)-Butanoic Acids 1 may be accurately determined by 1H and 13C nuclear magnetic resonance analysis of the corresponding derivatives 3 prepared by reaction with chiral reagents. Correlation with HPLC is signaled. 相似文献
998.
Santosh RajputChao-wei Leu Kasey WoodDavid StC Black Naresh Kumar 《Tetrahedron letters》2011,52(52):7095-7098
The activated dimethoxypyrrolo[3,2,1-ij]quinolin-6-one ring system was synthesized via two approaches, starting from an indole and quinolin-4-one, respectively. Subsequent demethylation led to both monohydroxy- and dihydroxypyrrolo[3,2,1-ij]quinolin-6-ones. 相似文献
999.
1000.
A series of derivatisation reactions between p-t-butyl calix[4]arene and ethyl bromoacetate were carried out in order to prepare 1,3 diester substituted calix[4]arene. Mass spectral data, obtained from direct injection of samples, indicated that the reactions were rich in the desired product. Since the ultra violet (UV) spectra of the desired product and possible impurities are very similar, liquid chromatography (LC) chromatographic data seemed to corroborate these results. However, when on-line LC-UV-MS was carried out and each LC peak subjected to MS analysis as it eluted, a very different picture emerged. It was found that many of these reactions actually contained high levels of the monoester product which, having less affinity for sodium in the MS, is therefore seriously underestimated in any direct injection assay. LC-diode array detection (DAD) methods were also used to help successfully identify and characterise the compounds being formed in these complex reactions. The overall results obtained in this paper allowed the optimal reaction conditions to be determined for this reaction. LC-MS analysis of the chromatographic peaks also identified the presence of two isomers of the diester substituted calix[4]arene (1,3 and 1,2 diesters). The combination of LC and UV/MS detection is required for accurate analysis of the products of such reactions. 相似文献