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排序方式: 共有188条查询结果,搜索用时 15 毫秒
101.
Kenjiro Wake 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2006,82(4):155-164
Hepatic stellate cells (HSCs) are vitamin-A storing collagen-producing cells in hepatic lobules. The three-dimensional structure of HSCs has been demonstrated with the Golgi method, the maceration method for scanning electron microscopy, and confocal laser scanning microscopy. Many thorn-like microprojections or spines extend from the subendothelial processes and make contacts with hepatocytes. One HSC entwines two or more sinusoids and about 20–40 hepatocytes to create a cellular unit, ‘the stellate cell unit’ or ‘stellon’. The Space of Disse is defined as the space between stellate cell-endothelial cell complex and hepatocytes. Intralobular heterogeneity of HSCs is assessed. HSCs develop from mesenchymal cells in the septum transversum. The developmental process of HSCs is reproduced partly in culture. In the lamprey abundant vitamin A is stored not only in HSCs, but in the fibroblast-like cells in the various other splanchnic organs. In vertebrates, the existence of both conventional fibroblast system in somatic tissues and vitamin A-storing cell system in splanchnic organs is suggested. 相似文献
102.
The thermal conductivity of diatomic liquids was analyzed using a nonequilibrium molecular dynamics (NEMD) method. Five liquids, namely, O2, CO, CS2, Cl2 and Br2, were assumed. The two-center Lennard-Jones (2CLJ) model was used to express the intermolecular potential acting on liquid molecules. First, the equation of state of each liquid was obtained using MD simulation, and the critical temperature, density and pressure of each liquid were determined. Heat conduction of each liquid at various liquid states [metastable (ρ=1.9ρcr), saturated (ρ=2.1ρcr), and stable (ρ=2.3ρcr)] at T=0.7Tcr was simulated and the thermal conductivity was estimated. These values were compared with experimental results and it was confirmed that the simulated results were consistent with the experimental data within 10%. Obtained thermal conductivities at saturated state were reduced by the critical temperature, density and mass of molecules and these values were compared with each other. It was found that the reduced thermal conductivity increased with the increase in the molecular elongation. Detailed analysis of the molecular contribution to the thermal conductivity revealed that the contribution of the heat flux caused by energy transport and by translational energy transfer to the thermal conductivity is independent of the molecular elongation while the contribution of the heat flux caused by rotational energy transfer to the thermal conductivity increases with the increase in the molecular elongation. Moreover, by comparing the reduced thermal conductivity at various states, it was found that the increase of thermal conductivity with the increase in the density, or pressure, was caused by the increase of the contribution of energy transfer due to molecular interaction. 相似文献
103.
Dr. Koji Numasawa Prof. Kenjiro Hanaoka Naoko Saito Prof. Yoshifumi Yamaguchi Takayuki Ikeno Honami Echizen Dr. Masahiro Yasunaga Dr. Toru Komatsu Dr. Tasuku Ueno Prof. Masayuki Miura Prof. Tetsuo Nagano Prof. Yasuteru Urano 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(15):6071-6076
Folate receptors (FRs) are membrane proteins involved in folic acid uptake, and the alpha isoform (FR-α) is overexpressed in ovarian and endometrial cancer cells. For fluorescence imaging of FRs in vivo, the near-infrared (NIR) region (650–900 nm), in which tissue penetration is high and autofluorescence is low, is optimal, but existing NIR fluorescent probes targeting FR-α show high non-specific tissue adsorption, and require prolonged washout to visualize tumors. We have designed and synthesized a new NIR fluorescent probe, FolateSiR-1 , utilizing a Si-rhodamine fluorophore having a carboxy group at the benzene moiety, coupled to a folate ligand moiety through a negatively charged tripeptide linker. This probe exhibits very low background fluorescence and afforded a tumor-to-background ratio (TBR) of up to 83 in FR-expressing tumor-bearing mice within 30 min. Thus, FolateSiR-1 has the potential to contribute to the research in the field of biology and the clinical medicine. 相似文献
104.
Koji Numasawa Kenjiro Hanaoka Naoko Saito Yoshifumi Yamaguchi Takayuki Ikeno Honami Echizen Masahiro Yasunaga Toru Komatsu Tasuku Ueno Masayuki Miura Tetsuo Nagano Yasuteru Urano 《Angewandte Chemie (International ed. in English)》2020,59(15):6015-6020
Folate receptors (FRs) are membrane proteins involved in folic acid uptake, and the alpha isoform (FR‐α) is overexpressed in ovarian and endometrial cancer cells. For fluorescence imaging of FRs in vivo, the near‐infrared (NIR) region (650–900 nm), in which tissue penetration is high and autofluorescence is low, is optimal, but existing NIR fluorescent probes targeting FR‐α show high non‐specific tissue adsorption, and require prolonged washout to visualize tumors. We have designed and synthesized a new NIR fluorescent probe, FolateSiR‐1 , utilizing a Si‐rhodamine fluorophore having a carboxy group at the benzene moiety, coupled to a folate ligand moiety through a negatively charged tripeptide linker. This probe exhibits very low background fluorescence and afforded a tumor‐to‐background ratio (TBR) of up to 83 in FR‐expressing tumor‐bearing mice within 30 min. Thus, FolateSiR‐1 has the potential to contribute to the research in the field of biology and the clinical medicine. 相似文献
105.
Naotake Nakamura Kenjiro Uno Ryoji Watanabe Tatsuhiro Ikeya Yoshihiro Ogawa 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(7):903-904
In the title compound, C15H32O2, one of the terminal hydroxyl groups has a gauche conformation with respect to the hydrocarbon skeleton, while the other is trans. The molecules lie parallel to the longest axis and form layers similar to those of the smectic A structure of liquid crystals. These features are similar to those of the homologues with an odd number of C atoms, but different from those with an even number. 相似文献
106.
The current status of our development work on lean NOx catalysts for application to future gasoline and diesel engines is described. As a result of further improvements in fuel economy, the temperature of exhaust gas will be lower and there will be smaller quantities of hydrocarbons (HCs) in the exhaust of future engines. Therefore, it is necessary to improve the activity of lean NOx catalysts at lower temperatures and achieve higher selectivity of the NOx–HC reaction. Utilizing precious metal catalysts is one effective way of improving catalyst activity at lower temperatures, and HC adsorption and reforming are two key technologies for improving the catalyst selectivity for the NOx–HC reaction. 相似文献
107.
Masaru Harada Toshiyuki Mori Satoshi Awatsu Kenjiro Fujimoto Mamoru Watanabe 《Research on Chemical Intermediates》2003,29(7-9):749-753
The interaction of NO, NO+O2 and NO2 with K x Ga x Sn8?x O16 powder, including potassium ions, has been investigated by temperature-programmed desorption. In the case of NO+O2, NO x storage rapidly increased with increasing concentration of O2 and the main peak has high intensity with a maximum around 600°C. These results indicate that K x Ga x Sn8?x O16 has NO x storage ability with high thermal stability and is one of the promising catalysts for NO x storage reduction. 相似文献
108.
Komatsu T Oushiki D Takeda A Miyamura M Ueno T Terai T Hanaoka K Urano Y Mineno T Nagano T 《Chemical communications (Cambridge, England)》2011,47(36):10055-10057
We studied the photobleaching of a library of boron dipyrromethene (BODIPY) derivatives with a range of electron densities, and found that the photobleaching rate is influenced by the electron-withdrawing capacity of the substituents. Electron-deficient BODIPYs generated less singlet oxygen, were less reactive to singlet oxygen, and were highly resistant to photobleaching. We confirmed the utility of one of these fluorophores, 2,6-diCO(2)R-BDP, for visualizing EGF receptor dynamics in cells expressing an SNAP-tagged EGF receptor. 相似文献
109.
Rational design of ratiometric near-infrared fluorescent pH probes with various pKa values, based on aminocyanine 总被引:1,自引:0,他引:1
Myochin T Kiyose K Hanaoka K Kojima H Terai T Nagano T 《Journal of the American Chemical Society》2011,133(10):3401-3409
Novel ratiometric, near-infrared fluorescent pH probes with various pK(a) values have been designed and synthesized on the basis of aminocyanine bearing a diamine moiety, and their photochemical properties were evaluated. Under acidic conditions, these pH probes showed a 46- to 83-nm red shift of the absorption maximum. This change is sufficiently large to permit their use as ratiometric pH probes, and is reversible, whereas monoamine-substituted aminocyanines showed irreversible changes because of their instability under acidic conditions. Furthermore, the pK(a) values of these probes can be predicted from the calculated pK(a) values of the diamine moieties, obtained from the SciFinder database. This design strategy is very simple and flexible, and should be applicable to develop NIR pH probes for various applications. 相似文献
110.
Abo M Urano Y Hanaoka K Terai T Komatsu T Nagano T 《Journal of the American Chemical Society》2011,133(27):10629-10637
Hydrogen peroxide is believed to play a role in cellular signal transduction by reversible oxidation of proteins. Here, we report the design and synthesis of a novel fluorescence probe for hydrogen peroxide, utilizing a photoinduced electron transfer strategy based on benzil chemistry to control the fluorescence. The practical value of this highly sensitive and selective fluorescence probe, NBzF, was confirmed by its application to imaging of hydrogen peroxide generation in live RAW 264.7 macrophages. NBzF was also employed for live cell imaging of hydrogen peroxide generated as a signaling molecule in A431 human epidermoid carcinoma cells. 相似文献