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191.
Uchiyama S Tomita R Sekioka N Imaizumi E Hamana H Hagiwara T 《Bioelectrochemistry (Amsterdam, Netherlands)》2006,68(2):119-125
Sulfhydryl groups of glucose oxidase (GOD) were reacted with maleimide groups of polymaleimidostyrene (PMS) which was coated onto the porous carbon sheet, and the carbon sheet immobilized by GOD was combined with an oxygen electrode to fabricate a glucose sensor. The activity of thiolated GOD immobilized to PMS is much larger than that of native GOD immobilized to PMS. The good linear relationship of glucose and oxygen current response was obtained in a concentration range from 0.1 to 2 mM and upper limit of linear range was found to be 3.0 mM. The immobilized GOD activity is highly dependent on pH at immobilization and the maximum activity was obtained at pH 5.5, probably because the SH groups of GOD that are indispensable for generation of enzyme activity is not exposed at this pH. It was found that PMS is very effective reagent to immobilize enzyme strongly via covalent bond, because high density of maleimide groups of PMS can catch not only exposed SH groups but also buried SH groups. 相似文献
192.
A method for a beam shaping optics is proposed to convert a laser beam profile into arbitrary required intensity distribution.
Surface profile of the beam shaping optics is designed by using Snell's law to convert the required intensity distribution
at the beam irradiation plane from the input intensity distribution. A computerized numerical control (CNC) lathe is employed
to fabricate the beam shaping optics, and acrylic resin is used for the material. The acrylic resin plate is cut by a ball
type of grinding wheel tool consisted on diamond powder and polished by a cone type felt buff with alumina ceramics powder.
The CNC lathe is powerful tool to control the position of these tools. The fabricated beam shaping optics is aspheric shape
with 4 mm of thickness and it works to convert the intensity distribution of multi-mode beam profile with 13 mm of diameter
into a flat top cylinder with 1 mm of diameter. A working distance of the beam shaping optics is 60 mm, and its transmittance
is over 98%. It succeeds to fabricate uniform melting mark of 0.6 mm diameter on a steel target by the YAG laser process. 相似文献
193.
Attempts have been made to alter the solidification microstructures of fiber reinforced aluminum composites by cooling the
ends of the fibers extending out of the mold. Experimental observations indicate that cooling the extended ends of the reinforcement
results in finer microstructures in the matrix and changes the nature of the interface. In this paper, numerical simulation
is performed on a two-dimensional axi-symmetric model to investigate the solidification process of metal matrix composite
(MMC) with the extended ends of the fibers cooled by a heat sink. The numerical simulation is based on the source-based enthalpy
method with finite volume discretization. The temperature profiles obtained by simulation are compared to the cooling curves
measured experimentally in order to validate the current mathematical model. It is found that the simulation result matches
the experimental data with reasonable agreement. 相似文献
194.
In order to improve the material properties of fiber-reinforced aluminum composites, experimental research has been carried
out to create finer matrix microstructures and novel interfaces between aluminum matrix (A2014) and carbon fibers using a
modified pressure infiltration technique. In this novel process the ends of the fibers extending outside the mold are cooled
by using a variety of heat sinks. Solidification microstructures show that the dendrite arm spacing in between and around
the fibers are much finer than in the region where there are no fibers. This suggests the possibility of refining the matrix
microstructures by cooling the fibers extending out of the mold. A numerical simulation is also performed to study the solidification
process of aluminum matrix by finite volume method. The cooling curves obtained by the simulation are compared with the experimentally
measured cooling curves in order to validate the numerical model. It is found that the simulation result closely matches the
experimentally obtained data. 相似文献
195.
Ryoichi Matsui Dr. Masataka Ohtani Kuniyo Yamada Dr. Takaaki Hikima Prof. Dr. Masaki Takata Dr. Takashi Nakamura Dr. Hiroyuki Koshino Dr. Yasuhiro Ishida Prof. Dr. Takuzo Aida 《Angewandte Chemie (International ed. in English)》2015,54(45):13284-13288
In situ polymerization of a bicellar mixture composed of a phospholipid and polymerizable surfactants afforded unprecedented stable bicelles. The polymerized composite showed an aligned phase over a wide thermal range (25 to >90 °C) with excellent 2H quadrupole splitting of the solvent signal, thus implying versatility as an alignment medium for NMR studies. Crosslinking of the surfactants also brought favorable effects on the kinetic stability and alignment morphology of the bicelles. This system could thus offer a new class of scaffolds for biomembrane models. 相似文献
196.
Ryoichi Kishi Aritoshi Matsuda Toshiaki Miura Kazunari Matsumura Kokoro Iio 《Colloid and polymer science》2009,287(5):505-512
We prepared thermo-responsive polymer hydrogels by γ-ray irradiation of aqueous solutions of N, N-diethylacrylamide at different temperatures below and above its lower critical solution temperature (LCST). Poly(N, N-diethylacrylamide) gel had a transparent and homogeneous structure when the radiation-induced polymerization and crosslinking
were carried out below the LCST (25 °C) of the polymer. On the other hand, cloudy and heterogeneous gels were formed at temperatures
above the LCST of the polymer (>35 °C). From environmental scanning electron microscopy observations, the gels prepared at
35 and 40 °C were seen to show sponge-like bi-continuous porous structures, while those prepared at 50 °C showed a porous
structure consisting of interconnected microspheres. For temperature changes between 10 and 40 °C, gels with porous structures
showed rapid volume transitions on a time scale of about a minute, not only for shrinking but also for swelling processes,
which is in remarkable contrast to the porous poly(N-isopropylacrylamide) hydrogels. 相似文献
197.
Prof. Ryoichi Kuwano Yuta Hashiguchi Ryuhei Ikeda Dr. Kentaro Ishizuka 《Angewandte Chemie (International ed. in English)》2015,54(8):2393-2396
The asymmetric hydrogenation of pyrimidines proceeded with high enantioselectivity (up to 99 % ee) using an iridium catalyst composed of [IrCl(cod)]2, a ferrocene‐containing chiral diphosphine ligand (Josiphos), iodine, and Yb(OTf)3 (cod=1,5‐cyclooctadiene). The chiral catalyst converted various 4‐substituted pyrimidines into chiral 1,4,5,6‐tetrahydropyrimidines in high yield. The lanthanide triflate is crucial for achieving the high enantioselectivity as well as for activating the heteroarene substrate. 相似文献
198.
[reaction: see text] Stereoselective syntheses of the C(1)-C(18) segment (segment A) and the C(19)-C(31) segment (segment B) are described in the preceding paper. This paper reports the key coupling reaction of both segments, 22-membered lactonization, and the crucial terminal amidation reaction culminating in the total synthesis of scytophycin C. 相似文献
199.
Dr. Ryoichi Kanega Erika Ishida Dr. Takaaki Sakai Dr. Naoya Onishi Dr. Akira Yamamoto Hiroki Yasumura Prof. Dr. Hisao Yoshida Hajime Kawanami Dr. Yuichiro Himeda Dr. Yukari Sato Dr. Akihiro Ohira 《Angewandte Chemie (International ed. in English)》2023,62(47):e202310976
For the application of CO2 as an energy storage material, a H2 storage system has been proposed based on the interconversion of CO2 and formic acid (or formate). However, energy losses are inevitable in the conversion of electrical energy to H2 as chemical energy (≈70 % electrical efficiency) and H2 to electrical energy (≈40 % electrical efficiency). To overcome these significant energy losses, we developed a system based on the interconversion of CO2 and formate for the direct storage and generation of electricity. In this paper, we report an aqueous redox flow battery system using homogeneous Ir catalysts with CO2-formate redox pair. The system exhibited a maximum discharge capacity of 10.5 mAh (1.5 Ah L−1), capacity decay of 0.2 % per cycle, and total turnover number of 2550 after 50 cycles. During charging-discharging, in situ fluorescence X-ray absorption fine structure spectroscopy based on an online setup indicated that the active species was in a high valence state of IrIV. 相似文献
200.
Hirotsu M Shimizu Y Kuwamura N Tanaka R Kinoshita I Takada R Teki Y Hashimoto H 《Inorganic chemistry》2012,51(2):766-768
The reaction of manganese(II) acetate with a xanthene-bridged bis[3-(salicylideneamino)-1-propanol] ligand, H(4)L, afforded the tetramanganese(II,II,III,III) complex [Mn(4)(L)(2)(μ-OAc)(2)], which has an incomplete double-cubane structure. The corresponding reaction using manganese(II) chloride in the presence of a base gave the tetramanganese(III,III,III,III) complex [Mn(4)(L)(2)Cl(3)(μ(4)-Cl)(OH(2))], in which four Mn ions are bridged by a Cl(-) ion. A pair of L ligands has a propensity to incorporate four Mn ions, the arrangement and oxidation states of which are dependent on the coexistent anions. 相似文献