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131.
132.
M. Kawaguchi 《Macromolecular Symposia》2000,160(1):85-90
Characteristics of viscous fingering patterns in polymer solutions were investigated by radially pushing air in a radial Hele‐Shaw cell containing hydroxypropyl methyl cellulose (HPMC) solutions. Low and high molecular weight HPMC samples were used. An increase in molecular weight easily yielded chain entanglements, which led to a strong shear thinning and an increase in elasticity. For the low molecular weight HPMC solutions, only the dense‐branching patterns were observed over the entire injection pressure range. When isopropyl alcohol was added into the HPMC solutions, leading to less elasticity, the pattern was tip‐splitting one, which is observed for Newtonian fluids. On the other hand, for the high molecular weight HPMC solutions, the resulting patterns showed a systematic change from dense‐branching to skewering patterns through tip‐splitting patterns as the injection pressure increased. The measured tip velocity was compared with the modified Darcy's law, but the coincidence is poor. The velocity corrected by the displaced area ratio provided a good linear relation. 相似文献
133.
134.
Yayoi Ozawa Shin‐ichi Sawada Nobuyuki Morimoto Kazunari Akiyoshi 《Macromolecular bioscience》2009,9(7):694-701
Highly branched cyclic dextrin derivatives (CH‐CDex) that are partly substituted with cholesterol groups have been synthesized. The CH‐CDex forms monodisperse and stable nanogels with a hydrodynamic radii of ≈10 nm by the self‐assembly of 4–6 CH‐CDex macromolecules in water. The CH‐CDex nanogels spontaneously trap 10–16 molecules of fluorescein isothiocyanate‐labeled insulin (FITC‐Ins). The complex shows high colloidal stability: no dissociation of trapped insulin is observed after at least 1 month in phosphate buffer (0.1 M , pH 8.0). In the presence of bovine serum albumin (BSA, 50 mg · mL?1), which is a model blood system, the FITC‐Ins trapped in the nanogels is continuously released (≈20% at 12 h) without burst release. The high‐density nanogel structure derived from the highly branched CDex significantly affects the stability of the nanogel–protein complex.
135.
Let \({\varphi: \mathbb{P}^N_K\to\mathbb{P}^N_K}\) be a morphism of degree d ≥ 2 defined over a field K that is algebraically closed field and complete with respect to a nonarchimedean absolute value. We prove that a modified Green function \({\hat{g}_\varphi}\) associated to \({\varphi}\) is Hölder continuous on \({\mathbb{P}^N(K)}\) and that the Fatou set \({\mathcal{F}(\varphi)}\) of \({\varphi}\) is equal to the set of points at which \({\hat{g}_\Phi}\) is locally constant. Further, \({\hat{g}_\varphi}\) vanishes precisely on the set of points P such that \({\varphi}\) has good reduction at every point in the forward orbit \({\mathcal{O}_\varphi(P)}\) of P. We also prove that the iterates of \({\varphi}\) are locally uniformly Lipschitz on \({\mathcal{F}(\varphi)}\) . 相似文献
136.
Kawaguchi M Ito R Sakui N Okanouchi N Saito K Nakazawa H 《Journal of chromatography. A》2006,1105(1-2):140-147
A novel method for the trace analysis of 17beta-estradiol (E2) in river water sample was developed, which involved stir bar sorptive extraction (SBSE) with in situ acylation (first derivatization) and thermal desorption (TD) with quartz wool assisted (QWA) in tube silylation (second derivatization), followed by gas chromatography-mass spectrometry (GC-MS), and is called the "dual derivatization method." The optimum conditions for SBSE with in situ acylation, such as the volume of acetic acid anhydride and the extraction time, were investigated. In addition, the optimum conditions for TD with QWA in tube silylation, such as the volume of N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and the TD temperature and hold time, were investigated as well. The detection limit (S/N = 3) and the quantitation limit (S/N>10) of E2 in the river water sample were 0.5 and 2 pg ml(-1) (ppt), respectively, by the dual derivatization method. In addition, the detection limit was 0.1 pg ml(-1) by using dual derivatization method with multi-shot mode. The calibration curve for E2 was linear in the range of 0.002-10 ng ml(-1) with correlation coefficients >0.999. The average recoveries of E2 (n = 6) at the concentrations of 0.05 and 1.0 ng ml(-1) from the river water sample were 93.1 (RSD: 1.4%) and 98.4% (RSD: 0.8%), respectively, with correction using the added surrogate standard, 17beta-estradiol-(13)C(4). This simple, accurate, sensitive and selective analytical method may be applicable to the determination of trace amounts of E2 in water samples. 相似文献
137.
Takahiro Tsukahara Yusuke Sakamoto Daisuke Aoshima Makoto Yamamoto Yasuo Kawaguchi 《Experiments in fluids》2012,52(4):877-890
The installation of windbreak sand fences around sand dunes is one of the most promising methods to suppress windblown sand
movement. In the study reported in this paper, we investigated the influence and validity of a small fence mounted on a model
sand dune, in order to understand the fence’s suppression mechanism on the sand movement. The flow field around the dune and
the process of sand-dune erosion were measured using LDV, PIV, and laser-sheet visualization techniques. A non-porous fence
was found to suppress sand movements in its upstream area, but to enhance erosion downstream of the fence. This intensive
erosion was caused by separated shear flow from the leading edge of the fence. In this study, four levels of porosity rate
of the fence were tested. The fence-porosity dependences of the turbulent flow field and the erosion were discussed. The shapes
of eroded sand dunes were found to depend on the porosity rate. The relationship between the sand-dune erosion and the flow
field around the dune was illustrated with schematic diagrams. We concluded that the most desirable fence porosity should
be 30% in order to avoid dune erosion if installed at a middle height on the stoss surface of a dune. This porosity provides
a mean velocity reduction with avoiding a separated flow, although the flow bleeding through the porous fence is accompanied
by grid turbulence and induces serious erosion in a narrow space behind the fence. Furthermore, we confirmed that the empirical
correlation of the critical friction velocity can be applied to sand movements influenced by a fence. 相似文献
138.
Hiroyuki Tanaka Toshifumi Shiroya Minako Hanasaki Tatsushi Isojima Hisao Takeuchi Haruma Kawaguchi 《Macromolecular Symposia》2008,266(1):81-84
Summary: Protein chips are important tools for high-throughput analysis of biological events. We have developed a novel method to prepare a protein-based hydrogel, that is, a “Three-Dimensional Nano-structured Protein Hydrogel” (3-D NPH), which is composed of protein and polymer nano-particles. The 3-D NPH could be easily prepared by dispensing a protein and polymer mixture on a substrate. Surprisingly, gold particles conjugated with protein A diffused into the 3-D NPH which was made of mouse IgG through the pores. We have shown that the protein chips made with our 3-D NPH method has tremendously improved sensitivity in detecting protein-protein interactions compared with that of direct protein immobilization methods. 相似文献
139.
Takashi Nakai Tai Hirakura Yuji Sakurai Tsuyoshi Shimoboji Masaki Ishigai Kazunari Akiyoshi 《Macromolecular bioscience》2012,12(4):475-483
A hyaluronic acid‐based anionic nanogel formed by self‐assembly of cholesteryl‐group‐bearing HA is designed for protein delivery. The HA nanogel spontaneously binds various types of proteins without denaturation, such as recombinant human growth hormone, erythropoietin, exendin‐4, and lysozyme. The HA nanogel shows unique colloidal properties, in particular that an injectable hydrogel is formed by salt‐induced association of the HA nanogel. A pharmacokinetic study in rats shows that an in situ gel formulation, prepared by simply mixing rhGH and HA nanogel in phosphate buffer, maintains plasma rhGH levels within a narrow range over one week. Therefore, HA nanogels offer a simple method for easy formulation of therapeutic proteins and are effective for sustained protein release systems.
140.
Kamagata K Kawaguchi T Iwahashi Y Baba A Fujimoto K Komatsuzaki T Sambongi Y Goto Y Takahashi S 《Journal of the American Chemical Society》2012,134(28):11525-11532
A method was developed to detect fluorescence intensity signals from single molecules diffusing freely in a capillary cell. A unique optical system based on a spherical mirror was designed to enable quantitative detection of the fluorescence intensity. Furthermore, "flow-and-stop" control of the sample can extend the observation time of single molecules to several seconds, which is more than 1000 times longer than the observation time available using a typical confocal method. We used this method to scrutinize the fluorescence time series of the labeled cytochrome c in the unfolded state. Time series analyses of the trajectories based on local equilibrium state analysis revealed dynamically differing substates on a millisecond time scale. This system presents a new avenue for experimental characterization of the protein-folding energy landscape. 相似文献