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71.
Kentaro Fujimoto Yoshiyasu Matsumoto Kohki Oikawa Jun-ichi Nomura Yasuyoshi Shimada Shunrou Fujiwara Kazunori Terasaki Masakazu Kobayashi Kenji Yoshida Kuniaki Ogasawara 《International journal of molecular sciences》2016,17(8)
The purpose of the present study was to determine whether cerebral hyperperfusion after revascularization inhibits development of cerebral ischemic lesions due to artery-to-artery emboli during exposure of the carotid arteries in carotid endarterectomy (CEA). In patients undergoing CEA for internal carotid artery stenosis (≥70%), cerebral blood flow (CBF) was measured using single-photon emission computed tomography (SPECT) before and immediately after CEA. Microembolic signals (MES) were identified using transcranial Doppler during carotid exposure. Diffusion-weighted magnetic resonance imaging (DWI) was performed within 24 h after surgery. Of 32 patients with a combination of reduced cerebrovascular reactivity to acetazolamide on preoperative brain perfusion SPECT and MES during carotid exposure, 14 (44%) showed cerebral hyperperfusion (defined as postoperative CBF increase ≥100% compared with preoperative values), and 16 (50%) developed DWI-characterized postoperative cerebral ischemic lesions. Postoperative cerebral hyperperfusion was significantly associated with the absence of DWI-characterized postoperative cerebral ischemic lesions (95% confidence interval, 0.001–0.179; p = 0.0009). These data suggest that cerebral hyperperfusion after revascularization inhibits development of cerebral ischemic lesions due to artery-to-artery emboli during carotid exposure in CEA, supporting the “impaired clearance of emboli” concept. Blood pressure elevation following carotid declamping would be effective when embolism not accompanied by cerebral hyperperfusion occurs during CEA. 相似文献
72.
The minimum void ratio is an index widely used to indicate the contraction characteristics and the densest state of soils. The minimum void ratio obtained by the traditional test method has been utilized to represent the density of soils irrespective of their fines content despite the restriction (FC ≤ 5%). By considering the effect of the blow count, pore water, and their primary properties, the applicability of the minimum void ratio to soils containing fines was examined with an automatic tapping machine. It was confirmed that the blow count of the traditional method is not sufficient for soils with a high fines content. Furthermore, the presence of pore water had a significant effect on the minimum void ratio of soils containing fines. The characteristics of the cyclic minimum void ratio, which indicates the minimum void ratio obtained throughout the repetition of liquefaction and drainage, were also examined. 相似文献
73.
Yasumasa?Minemoto Shuji?AdachiEmail author Yuji?Shimada Toshihiro?Nagao Toshio?Iwata Yoshie?Yamauchi-Sato Takaya?Yamamoto Tadashi?Kometani Ryuichi?Matsuno 《Journal of the American Oil Chemists' Society》2003,80(7):675-678
The autoxidation processes of the cis-9,trans-11 (c9,t11) and trans-10,cis-12 (t10,c12) isomers of CLA were separately observed at ca. 0% RH and different temperatures. The t10,c12 CLA oxidized faster than the c9,t11 isomer at all tested temperatures. The first half of the oxidation process of t10,c12 CLA obeyed an autocatalytic-type rate expression, but the latter half followed first-order kinetics. On the other hand,
the entire oxidation process of c9,t11 CLA could be expressed by the autocatalytic-type rate expression. The apparent activation energies and frequency factors
for the autoxidation of the isomers were estimated from the rate constants obtained at various temperatures based on the Arrhenius
equation. The apparent activation energies for the CLA isomers were greater than those for the nonconjugated n−6 and n−3 PUFA
or their esters. However, the enthalpyentropy compensation held during the autoxidation of both the CLA and PUFA. This suggested
that the autoxidation mechanisms for the CLA and PUFA were essentially the same. 相似文献
74.
S. Shimada M. Tanaka H. Kiyono K. J. D. MacKenzie 《Journal of the European Ceramic Society》2001,21(16):2811-2819
An attempt was made to prepare various F-doped β-, O-, X-, and -SiAlONs from a mixture of Si3N4, SiO2, Al2O3, AlN, or Y2O3 using AlF3 or topaz as the fluorine source by HIPing at 1500–1800°C and 150 MPa. The phases were identified and the z, x, and m/n values determined for β-, O-, and -SiAlONs by X-ray diffraction. When AlF3 was used, a single phase ceramic (O-SiAlON) was produced from a mixture of -Si3N4 and SiO2 at 1500°C, with a mixture of O- and β-SiAlONs formed at 1700°C. A mixture of -Si3N4, AlN, and Y2O3 with AlF3 produced β-/Y--SiAlON ceramics at 1730°C. The use of topaz produced the β-SiAlON ceramic with a trace of mullite from a mixture of -Si3N4 and AlN at 1770°C and mixed phase β-/O-SiAlON ceramics from -Si3N4 and SiO2 at 1700°C. Single phase X-SiAlON could not be obtained under the present conditions. The microstructures of the single phase O- and β-SiAlON ceramics and the β-/Y--SiAlON mixture showed the growth of O- and β-SiAlON and Y--SiAlON crystals with hexagonal and/or long rod-like or platy shapes in a matrix of F-containing glassy phase. The compositions of the SiAlON crystals and the glass phase were semi-quantitatively determined by EDX; the total glass phase was estimated by a quantitative Rietveld XRD powder method. The F-doped β-SiAlON ceramics showed better corrosion resistance towards NaCl vapor and lower Vickers hardnesses. 相似文献
75.
Akiko?Kawashima Toshihiro?NagaoEmail author Yomi?Watanabe Takashi?Kobayashi Ikuo?Ikeda Yoshio?Tominaga Yuji?Shimada 《Journal of the American Oil Chemists' Society》2004,81(11):1013-1020
TAG (MLM) with medium-chain FA (MCFA) at the 1,3-positions and long-chain FA (LCFA) at the 2-position, and TAG (LMM) with
LCFA at the 1(3)-position and MCFA at 2,3(1)-positions are a pair of TAG regioisomers. Large-scale preparation of the two
TAG regioisomers was attempted. A commercially available FFA mixture (FFA-CLA) containing 9-cis, 11-trans (9c, 11t)- and 10t,12c-CLA was selected as LCFA, and caprylic acid (C8FA) was selected as MCFA. The MLM isomer was synthesized by acidolysis of acyglycerols (AG) containing two CLA isomers with
C8FA: A mixture of AG-CLA/C8 FA (1∶10, mol/mol) and 4 wt% immobilized Rhizomucor miehei lipase was agitated at 30°C for 72 h. The ratio of MLM to total AG was 51.1 wt%. Meanwhile, LMM isomer was synthesized by
acidolysis of tricaprylin with FFA-CLA: A mixture of tricaprylin/FFA-CLA (1∶2, mol/mol) and 4 wt% immobilized R. miehei lipase was agitated at 30°C for 24 h. The ratio of LMM to total AG was 51.8 wt%. MLM and LMM were purified from 1,968 and
813 g reaction mixtures by stepwise short-path distillation, respectively. Consequently, MLM was purified to 92.3% with 49.1%
recovery, and LMM was purified to 93.2% with 52.3% recovery. Regiospecific analyses of MLM and LMM indicated that the 2-positions
of MLM and LMM were 95.1 mol% LCFA and 98.3 mol% C8 FA, respectively. The results showed that a process comprising lipase reaction and short-path distillation is effective for
large-scale preparation of high-purity regiospecific TAG isomers. 相似文献
76.
The design of an ultraprecision displacement sensor with sub-nanometre resolution is proposed for the use of ultraprecision technologies. The sensor is based on the highly sensitive detection of power change at a specific point in light reflected from an object surface when the surface is subject to a small displacement. The sensor consists of a single light source, the reflective object and reference surfaces, optical fibre bundles for tranmission of the illuminating and the reflected light, and the photodiode set-up. In operation, the object and the reference surfaces are illuminated by light transmitted through the optical fibre bundle from the single light source. The reflected light from both surfaces is then transmitted through the optical fibre bundle to two individual but equivalent photodiodes. By using a differential amplifier, the diodes give a highly sensitive displacement signal which is included in the total signal of the reflected light. The sensor proposed has some distinctive features in its performance, such as non-contact measurement, a high resolution of 0.5 nm, a wide working range of about 30 μm within 5% linearity, and the sufficient stability of 1 nm in 20 s for specific research purposes. 相似文献
77.
Koji Fushimi Takatoshi Shimada Hiroki Habazaki Hidetaka Konno Masahiro Seo 《Electrochimica acta》2011,(4):1773
Depassivation–repassivation of iron surfaces in boric–borate solutions were investigated by using the micro-indentation test. A pair of current peaks due to repair of the passive film following rupture of the film were observed during a series of indenter drives, i.e., loading and unloading of the indenter. The shape of the current peak depended on environmental conditions (conductivity and pH of the solution) and substrate conditions (mechanical processing history, alloyed element) as well as indentation conditions (repetition, maximum depth, and maximum load). Plastic deformation of the surface was accompanied by surface depassivation, while no depassivation occurred during the elastic deformation, indicating that the passive film on iron has a ductile property. The solution conditions did not affect the scale of depassivation but affected the rate of repassivation. Dislocations in the substrate made surface depassivation difficult but enhanced reactivity during the repassivation. The test also revealed that type-312L stainless steel has high corrosion resistance in a concentrated NaCl solution. 相似文献
78.
Takanori Isobe Taku Takaku Tadayuki Kitahara Hideo Sumitani Ryuichi Shimada 《Electrical Engineering in Japan》2009,169(4):65-74
This paper proposes a power supply suitable for driving linear induction motors. The power supply consists of a voltage source inverter (VSI) and a magnetic energy recovery switch (MERS). Circuit configuration and operation principles of the power supply are described. Power factor correction by MERS can increase the output power. Technical advantages of using MERS compared with increasing the rated voltage of VSI are discussed. Some experiments with a linear induction motor were conducted. The results confirm that MERS can reduce the capacity of the VSI or increase the output with the same VSI capacity. The number of devices and magnitude of losses are evaluated on a large‐scale drive system. A half‐bridge type of MERS is provided and discussed. The half‐bridge MERS mitigates disadvantages of using MERS. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(4): 65–74, 2009; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.20832 相似文献
79.
Kikuo Matsui Hideki Shimada Takashi Sasaoka Hirofumi Furukawa Takeshi Ueda Atsuko Yabuki 《国际露天开采、回填与环境杂志》2013,27(3):185-204
Conventional highwall mining extracts coal with an auger machine or a continuous miner from exposed seams at the base of opencut or strip operations. However, under poor strata and high stress conditions, highwall mining cannot be conducted due to pillar and roof failures. In such cases, punch highwall mining is more effective than the conventional highwall mining. This paper describes conventional highwall mining and punch highwall mining systems and discusses the stability of the highwall due to punch highwall mining at opencut coal mines. 相似文献
80.
Hiroaki Takeda Takeshi Shimada Yoshiaki Katsuyama Tadashi Shiosaki 《Journal of Electroceramics》2009,22(1-3):263-269
The electric properties of BaTiO3–(Bi1/2Na1/2)TiO3 (BT–BNT) solid solution ceramics were studied as a lead-free PTCR (positive temperature coefficient of resistivity) thermistor material usable over 130°C. For determining the maximum switching temperature T s, the phase diagram of BT–BNT binary system was clarified. Two semiconductorization processes and their electric properties are described. The lanthanum(La)-doped BBNT ceramics sintered in air still showed dielectric behaviors, but the niobium(Nb)-doped ones had a low resistivity at room temperature, ρ RT, on the order of 103 Ωcm and showed a PTC behavior. Sintering under a low O2 atmosphere produces BT–BNT ceramics with less than 102 Ωcm compared to those prepared in air. Our current research produced the BBNT ceramics with T s values around 210°C by increasing the (Bi1/2Na1/2) content in the ceramics. 相似文献