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排序方式: 共有683条查询结果,搜索用时 15 毫秒
671.
Gaku Okuma Masaya Endo Haruki Minagawa Ryo Inoue Hideki Kakisawa Takuma Kohata Toshio Osada Takafumi Yamamoto Masaki Azuma Akihisa Takeuchi Masayuki Uesugi Olivier Guillon Fumihiro Wakai 《Advanced Engineering Materials》2023,25(18):2201534
The mechanical reliability of products must be assured for scaling up and production of complex-shaped components by spark plasma sintering (SPS) of spray-dried granules. The evolution of morphologies of pores and defects, which control the mechanical strength, is investigated by using synchrotron X-ray multiscale tomography during SPS of alumina granules at 1300 °C. While large defects arising from the hierarchical granule packing structure cannot be removed by pressureless sintering, crack-like defects and branched rodlike defects are almost eliminated by SPS at stresses higher than 30 and 50 MPa, respectively. But, small ellipsoidal porous regions, which may arise from aggregates or dimples of granules, cannot be removed even at a pressure of 50 MPa. A very large defect is also found by using micro-CT. It is supposed that this defect is formed from a large void in loosely packed granules. The shrinkage of large voids and the elimination of crack-like defects are explained by the theoretical prediction based on the continuum theory of sintering. 相似文献
672.
Minhong Lim Hyeongguk An Jiyeon Seo Mingyu Lee Hyuntae Lee Hyeokjin Kwon Hee-Tak Kim Daniel Esken Ryo Takata Hyun A Song Hongkyung Lee 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(43):2302722
Tailoring the Li+ microenvironment is crucial for achieving fast ionic transfer and a mechanically reinforced solid–electrolyte interphase (SEI), which administers the stable cycling of Li-metal batteries (LMBs). Apart from traditional salt/solvent compositional tuning, this study presents the simultaneous modulation of Li+ transport and SEI chemistry using a citric acid (CA)-modified silica-based colloidal electrolyte (C-SCE). CA-tethered silica (CA-SiO2) can render more active sites for attracting complex anions, leading to further dissociation of Li+ from the anions, resulting in a high Li+ transference number (≈0.75). Intermolecular hydrogen bonds between solvent molecules and CA-SiO2 and their migration also act as nano-carrier for delivering additives and anions toward the Li surface, reinforcing the SEI via the co-implantation of SiO2 and fluorinated components. Notably, C-SCE demonstrated Li dendrite suppression and improved cycling stability of LMBs compared with the CA-free SiO2 colloidal electrolyte, hinting that the surface properties of the nanoparticles have a huge impact on the dendrite-inhibiting role of nano colloidal electrolytes. 相似文献
673.
674.
Oikawa Ryo Doi Akio Ishida Masaru Chakraborty Basabi 《Artificial Life and Robotics》2023,28(2):460-470
Artificial Life and Robotics - Percutaneous coronary intervention (PCI) is mainly used in the treatment of stenosis of the coronary arteries of the heart characteristic of coronary artery disease,... 相似文献
675.
Yang Gao Ryo Iwasaki Daiki Hamana Junya Iihama Sawao Honda Munni Kumari Tomokatsu Hayakawa Samuel Bernard Philippe Thomas Yuji Iwamoto 《International Journal of Applied Ceramic Technology》2023,20(1):153-165
We report the first synthesis of β-SiAlON:Eu2+ phosphors from single-source precursors, perhydropolysilazane (PHPS), chemically modified with Al(OCH(CH3)2)3, and EuCl2. The reactions occurring during the precursor synthesis and the subsequent thermal conversion of polymeric precursors into β-SiAlON:Eu2+ phosphors have been studied by a complementary set of analytical techniques, including infrared spectroscopy, gas chromatography–mass spectrometry, thermogravimetry–mass spectrometry, X-ray diffraction (XRD), photoluminescence spectroscopy, and scanning electron microscopy. It has been clearly established that Al(OCH(CH3)2)3 immediately reacted with PHPS to afford N–Al bonds at room temperature, whereas N–Eu bond formation was suggested to proceed above 600°C accompanied by the elimination of HCl up to 1000°C in flowing N2. The subsequent 1800°C-heat treatment for 1 h under an N2 gas pressure at 980 kPa allowed converting the single-source precursors into fine-grained β-SiAlON:Eu2+ phosphors. XRD analysis revealed that the Al/Si of .09 was the critical atomic ratio in the precursor synthesis to afford single-phase β-SiAlON (z = .55). Moreover, Eu2+-doping was found to efficiently reduce the carbon impurity in the host β-SiAlON. The polymer-derived β-SiAlON:Eu2+ phosphors exhibited green emission under excitation at 460 nm and achieved the highest green emission intensity at the critical dopant Eu2+ concentration at 1.48 at%. 相似文献
676.
Toru Hashimoto Satoshi Ishii Reiko Yano Hiroki Miura Ken Sakata Ryo Takeuchi 《Advanced Synthesis \u0026amp; Catalysis》2015,357(18):3901-3916
The complex [Ir(cod)Cl]2/DPPF or rac‐BINAP is an efficient catalyst for the [2+2+2] cycloaddition of α,ω‐diynes with cyanamides. A wide range of cyanamides derived from secondary amines are good coupling partners for α,ω‐diynes. The reaction of unsymmetrical α,ω‐diynes possessing two different internal alkyne moieties with cyanamides is regioselective. A competitive experiment showed that cyanamide is more reactive than nitrile. This higher reactivity of cyanamide than nitrile was analyzed based on density functional theory (DFT) calculations at the B3LYP level.
677.
Artificial Life and Robotics - According to a survey on the cause of death among Japanese people, lifestyle-related diseases (such as malignant neoplasms, cardiovascular diseases, and pneumonia)... 相似文献
678.
679.
Shin Aizu Shuta Takimoto Naoto Tanibata Hayami Takeda Masanobu Nakayama Ryo Kobayashi 《Journal of the American Ceramic Society》2023,106(5):3035-3044
The realization of high-energy-density all-solid-state Li-ion batteries requires materials exhibiting both high Li-ion conductivity and high deformability, as exemplified by Li3MCl6-type chlorides. Herein, we optimized the classical force-field (FF) parameters for 36 Li- and Cl-containing compounds to reproduce the results of high-precision first-principles calculations and performed rapid FF molecular dynamics (MD) calculations to determine their Li-ion conductivities. In addition, shear moduli were evaluated by first-principles calculations and used as a deformability index. Li4Mn3Cl10 was selected based on its Li-ion conductivity, stiffness, and thermodynamic stability. In accordance with the low calculated shear modulus (11.7 GPa), the cold-pressed compact had a high relative density of 98%, which indicated good deformability. The room-temperature conductivity (3.9 mS cm−1) was similar to that (1.6 mS cm−1) obtained by high-precision first-principles MD calculations. The Li-ion conductivity of synthesized Li4Mn3Cl10 (18 µS cm−1) was relatively rather high compared to those of known chloride materials but much lower than the calculated value, which was ascribed to the fact that calculations were performed for the high-temperature phase, whereas synthesis yielded the low-temperature phase. The material screening method greatly increases the speed of material exploration and expands the application possibilities of chloride materials for all-solid-state batteries. 相似文献
680.
Ryo Nakamura Hiroshi Masuda Hidehiro Yoshida 《Journal of the American Ceramic Society》2023,106(3):2061-2072
Local mechanical responses near single grain boundaries (GBs) of 9.8 mol% Y2O3-stabilized ZrO2 bicrystals, SrTiO3 bicrystal, and Al2O3 polycrystal were investigated by nanoindentation at room temperature to reveal single GB contributions to the mechanical properties. Contrary to the concept of the Hall–Petch strengthening, the hardness showed negligible variations among grain interiors, GB vicinities, and just on GBs in the samples. Importantly, the hardness may be underestimated owing to GB grooving in thermally etched samples. Despite the negligible change in intrinsic hardness, the transmission electron microscopy observation of the ZrO2 specimen under impressions revealed dislocation pileups at GBs. These results suggest that single GBs of oxide ceramics prevented dislocation movement but with limited strengthening contributions. This should correspond to the macroscopic Hall–Petch behaviors in oxide ceramics, where the Hall–Petch coefficients normalized by friction stress are significantly smaller than those in metals. 相似文献