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461.
In this study, we applied photo-induced graft polymerization to micropatterned surface modification of polydimethylsiloxane (PDMS) with poly(ethylene glycol). Two types of monomers, polyethylene glycol monoacrylate (PEGMA) and polyethylene glycol diacrylate (PEGDA), were tested for surface modification of PDMS. Changes in the surface hydrophilicity and surface element composition were characterized by contact angle measurement and electron spectroscopy for chemical analysis. The PEGMA-grafted PDMS surfaces gradually lost their hydrophilicity within two weeks. In contrast, the PEGDA-grafted PDMS surface maintained stable hydrophilic characteristics for more than two months. Micropatterned protein adsorption and micropatterned cell adhesion were successfully demonstrated using PEGDA-micropatterned PDMS surfaces, which were prepared by photo-induced graft polymerization using photomasks. The PEGDA-grafted PDMS exhibited useful characteristics for microfluidic devices (e.g. hydrophilicity, low protein adsorption, and low cell attachment). The technique presented in this study will be useful for surface modification of various research tools and devices. 相似文献
462.
Ken-Ichi Kubo 《Pramana》2001,57(2-3):379-387
We briefly review concept of the quark recombination (QRC) model and a general success of the model. To solve the existing
problem, so called anomalous spin observables, in the high energy hyperon spin phenomena, we propose a mechanism; the primarily
produced quarks, which are predominantly u and d quarks, act as the leading partons to form the hyperons. Extension of the quark recombination concept with this mechanism
is successful in providing a good account of the anomalous spin observables. Another kind of anomaly, the non-zero analysing
power and spin depolarization in the Λ hyperon productions, are also discussed and well understood by the presently proposed
mechanism. Recently, a further difficulty was observed in an exclusive ΛK
+
p production and wel will indicate a possible diagram for resolving it. 相似文献
463.
464.
Optical Review - Heat-assisted magnetic recording (HAMR) is a promising technology for achieving more than 10 Tbit/inch2 recording density. A near-field transducer (NFT), which forms a small light... 相似文献
465.
Firyon Ko Kazunori Hirabayashi Toshio Shimizu Ken-ichi Sugiura 《Tetrahedron letters》2018,59(48):4251-4254
An unexpected ketone was obtained in the synthesis of tetrabenzo[a,d,j,m]coronene having tert-butyl groups from Thiele’s hydrocarbon derivative. The structure of the product was confirmed by not only spectroscopic but also diffraction studies. This product was formed by the rearrangement reaction of one phenyl group and this reaction could be analogous to the pinacol-pinacolone rearrangement. 相似文献
466.
467.
Tomohiro Hirano Misato Sugiura Ryuya Endo Miyuki Oshimura Koichi Ute 《Journal of polymer science. Part A, Polymer chemistry》2020,58(20):2857-2863
The stereochemical analysis of polymers derived from N,N-disubstituted acrylamides is usually difficult. The diad tacticity can be determined from the 1H nuclear magnetic resonance (NMR) signals of the main-chain methylene groups. However, the splitting because of the configurational sequences is poor, even in 13C NMR, which does not allow determination of the tacticity at the triad level. In contrast, the stereochemical analysis of polymers derived from N-monosubstituted acrylamides is easily conducted and the triad tacticity can be determined from the 13C signals of the main-chain methine groups. Thus, stereochemical analysis of N,N-disubstituted polymers should be able to be conducted if the polymers are transformed into N-monosubstituted polymers with retention of the configurational sequence. Poly(N-tert-butyl-N-n-propylacrylamide) was radically prepared, and de-tert-butylation was conducted by treatment with scandium triflate in a mixed solvent of CH3CN and 1,4-dioxane at 50, 80, and 110°C. 1H NMR analysis of the resulting polymers indicated quantitative conversion after 72 hr, regardless of the temperature. 13C NMR analysis of the transformed polymers confirmed that the configurational sequences were retained during the reaction. Thus, the triad stereochemical analysis of N,N-disubstituted polymers was successfully conducted by de-tert-butylation as a polymer reaction, followed by 13C NMR analysis of the transformed polymers. 相似文献
468.
469.
Takaaki Iwamoto Philip J. Brooks Tomohisa Nishiwaki Kazuki Nishimura Nobuhiko Kobayashi Shigeki Sugiura Toshio Mori 《Photochemistry and photobiology》2014,90(4):829-836
Xeroderma pigmentosum (XP) is a genetic disorder associated with defects in nucleotide excision repair, which eliminates a wide variety of helix‐distorting types of DNA damage including sunlight‐induced pyrimidine dimers. In addition to skin disease, approximately 30% of XP patients develop progressive neurological disease, which has been hypothesized to be associated with the accumulation of a particular type of oxidatively generated DNA damage called purine 8,5′‐cyclo‐2′‐deoxynucleosides (purine cyclonucleosides). However, there are no currently available methods to detect purine cyclonucleosides in DNA without the need for DNA hydrolysis. In this study, we generated a novel monoclonal antibody (CdA‐1) specific for purine cyclonucleosides in single‐stranded DNA that recognizes 8,5′‐cyclo‐2′‐deoxyadenosine (cyclo‐dA). An immunoassay using CdA‐1 revealed a linear dose response between known amounts of cyclo‐dA in oligonucleotides and the antibody binding to them. The quantitative immunoassay revealed that treatment with Fenton‐type reagents (CuCl2/H2O2/ascorbate) efficiently produces cyclo‐dA in DNA in a dose‐dependent manner. Moreover, immunofluorescent analysis using CdA‐1 enabled the visualization of cyclo‐dA in human osteosarcoma cells, which had been transfected with oligonucleotides containing cyclo‐dA. Thus, the CdA‐1 antibody is a valuable tool for the detection and quantification of cyclo‐dA in DNA, and may be useful for characterizing the mechanism(s) underlying the development of XP neurological disease. 相似文献
470.
Yutaro Sugiura Haruya Suzuki Takuma Otomo Takaaki Miyazaki Toshiyuki Takayanagi Masanori Tachikawa 《Journal of computational chemistry》2020,41(17):1576-1585
Positron binding energies (PBEs) of 41 polyatomic molecules were calculated using the positron–electron correlation-polarization potential (CPP) approach and compared with experimentally measured values. In this approach, the short-range positron–electron potential is modeled using the density-functional expression, whereas the long-range potential is approximated by the attractive polarization potential. The positron–electron CPP model based on local-density approximation yields larger PBEs than experimental values; however, the calculated values can be substantially improved by introducing generalized gradient approximation. We also investigated the conformational dependence of PBEs for representative molecules. 相似文献