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排序方式: 共有340条查询结果,搜索用时 281 毫秒
111.
Srikrishnan Siva Subramanian Tatsuya Ishikawa Tetsuya Tokoro 《Soils and Foundations》2018,58(3):582-601
In Hokkaido, Japan, soil slope failures occur frequently during the snow melting season. These slope failures are triggered by the excess amount of water derived from snowmelt and rainfall. For the prediction of snowmelt-induced soil slope failures in seasonally cold regions, an early warning criterion is required. The existing Japanese early warning criteria for sediment disasters, i.e., the relationship between the 60-min cumulative rainfall and the Soil Water Index (SWI), the effective rainfall index etc., consider the influence of rainfall and the time-dependent random moisture of the soil. However, these criteria do not consider the soil moisture contributed by the snowmelt water. In this study, therefore, the applicability of the existing early warning criteria to predict snowmelt-induced soil slope failures is examined. An empirical method to quantify the amount of snowmelt water is presented. Various scenarios of conceptual soil slope failures are studied using numerical simulations under different magnitudes of rainfall and snowmelt water. As a result, a revision is introduced for the SWI and the effective rainfall index, adding the amount of snowmelt water to that of rainfall, and slope failure scenarios are studied. Based on the results, a new early warning criterion, the Effective Precipitation (EP) index, is introduced. It is found that the new failure criterion performs well for the prediction of snowmelt-induced soil slope failures. 相似文献
112.
Takakuda K Koyama Y Matsumoto HN Shirahama N Akita K Shoji D Ogawa T Kikuchi M Tanaka J 《Journal of nanoscience and nanotechnology》2007,7(3):738-741
Two new bioabsorbable inorganic/organic composite materials were developed for bone regeneration. One material used was beta-TCP/PLGC in which poly(L-lactide-co-glycolide-co-epsilon-caprolactone) and beta-tricalcium phosphate were used as the matrix and filler, respectively. The other material used was HAp/Col-a soft nanocomposite of hydroxyapatite and type I collagen. Using these composites, two bone implants were designed. The efficacy of these implants was investigated by applying them to the critical-sized bone defects that were created in the canine tibia. Although no tissue engineering techniques such as application of growth factors or stem cells was utilized, successful healing was observed. These results suggested that bone regeneration in the critical-sized defects is possible without the use of growth factors or stem cells if the materials and the bone implants are suitably designed. 相似文献
113.
Hiroko Yamashita Prof. Makoto Oba Dr. Takashi Misawa Prof. Masakazu Tanaka Dr. Takayuki Hattori Dr. Mikihiko Naito Dr. Masaaki Kurihara Dr. Yosuke Demizu 《Chembiochem : a European journal of chemical biology》2016,17(2):137-140
Two types of cationic cyclic α,α‐disubstituted α‐amino acids: Api (which possesses a lysine mimic side chain) and ApiC2Gu (which possesses an arginine mimic side chain), were developed. These amino acids were incorporated into an arginine‐based peptide sequence [(l ‐Arg‐l ‐Arg‐dAA)3: dAA=Api or ApiC2Gu], and the relationship between the secondary structures of the resulting peptides and their ability to pass through cell membranes was investigated. The peptide containing ApiC2Gu formed a stable α‐helical structure and was more effective at penetrating cells than the nonhelical Arg nonapeptide (R9). Furthermore, the peptide was able to deliver plasmid DNA into various types of cells in a highly efficient manner. 相似文献
114.
115.
This paper proposes new testing methods for evaluating the effects of freeze-thaw action on the deformation-strength characteristics and the water retention-permeability characteristics of granular materials under unsaturated conditions. A triaxial apparatus and a permeability apparatus for unsaturated soils, with cooling systems to control the temperature of soil specimens and use the pressure membrane method instead of the pressure plate method, were newly developed in order to examine the hydro-mechanical behavior of unsaturated soils subjected to the freeze-thaw sequence, as experienced by in-situ soils in cold regions. Results indicate that the proposed testing methods with these newly developed test apparatuses are highly useful in the evaluation of the effect of freeze-thaw action on the hydro-mechanical behavior of unsaturated granular materials and in the reduction of total testing time. 相似文献
116.
Kajita H Akutsu C Hatakeyama E Komukai T 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2008,49(3):189-195
A multiresidue method was developed for determination of nine aminoglycoside antibiotics (streptomycin, dihydrostreptomycin, spectinomycin, neomycin, kanamycin, gentamicin, destomycin A, apramycin, and tobramycin) in milk by LC/MS/MS. The drugs were extracted with 0.01 mol/L potassium dihydrogen phosphate containing 2% trichloroacetic acid, and the extracted solution was cleaned on cation-exchange cartridge columns (Oasis WCX and Oasis MCX). LC separation was performed on a TSK-gel VMpak25 column (50 mmx2.0 mm i.d.) using gradient elution with 0.1% formic acid and acetonitrile containing 0.1% formic acid as the mobile phase. Recoveries of the drugs spiked at 0.01 or 0.1 microg/g in milk ranged from 66.1 to 110.8%, with a coefficient of variation of less than 17.1%. Limits of quantification of the drugs in milk were 0.001 approximately 0.01 microg/g. This method was used for analysis of milk from a lactating cow treated for clinical mastitis with two intramammary infusions of kanamycin (KM). Milk samples were analyzed during the withdrawal times at 12-hour intervals. KM concentrations were lower than the Japanese provisional MRLs (0.4 microg/g) at 60 hours after infusion, and subsequently fell to 0.01 microg/g. 相似文献
117.
Towards the development of a mechanical model that can be part of multi-physical analysis of frozen soils, a program of systematic frozen-unfrozen parallel triaxial tests at different temperatures and strain rates was conducted. The mechanical behavior of the reconstituted high-plasticity clay samples was investigated and interpreted through a state concept based on Ladanyi and Morel’s (1990) postulate on the unique relationship between the inter-particle “effective” stress and the strain path. The Critical State Lines (CSLs) for clay specimens frozen undrained were mapped by referring to the shear behavior of unfrozen specimens sharing the same strain history. With other conditions set identical, the shear strength linearly increased with a decrease in the temperature for the range from ?10 °C to ?2 °C, and log-linearly increased with an increase in the strain rate for the range from 0.001%/min to 0.1%/min. Direct comparison of the strain-rate effects between frozen and unfrozen specimens with identical strain paths and states in the soil skeleton clearly indicates that the viscoplasticity derives from that of pore ice. A conceptual interpretative framework invoking temperature- and strain rate-dependent state bounding surfaces and CSLs was proposed to describe the behavior of frozen soils under steady and non-steady temperature and strain rate. The above observations of the behavioral features of frozen and unfrozen soils, with further experimental work, are expected to lead to the construction of a unified framework for describing the behavior under both states and the transition between them. 相似文献
118.
Piyanuch Sommani Hiroshi Tsuji Hiroko Sato Junzo Ishikawa 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2010,268(19):3231-3234
We have investigated the irradiation effect of negative-ion implantation on the changes of physical surface property of polytetrafluoroethylene (PTFE) for controlling the adhesion property of stem cells. Carbon negative ions were implanted into PTFE sheets at fluences of 1 × 1014-1 × 1016 ions/cm2 and energies of 5-20 keV. Wettability and atomic bonding state including the ion-induced functional groups on the modified surfaces were investigated by water contact angle measurement and XPS analysis, respectively. An initial value of water contact angles on PTFE decreased from 104° to 88° with an increase in ion influence to 1 × 1016 ions/cm2, corresponding to the peak shifting of XPS C1s spectra from 292.5 eV to 285 eV with long tail on the left peak-side. The change of peak position was due to decrease of C-F2 bonds and increase of C-C bonds with the formation of hydrophilic oxygen functional groups of OH and CO bonds after the ion implantation. After culturing rat mesenchymal stem cells (MSC) for 4 days, the cell-adhesion properties on the C−-patterned PTFE were observed by fluorescent microscopy with staining the cell nuclei and their actin filament (F-actin). The clear adhesion patterning of MSCs on the PTFE was obtained at energies of 5-10 keV and a fluence of 1 × 1015 ions/cm2. While the sparse patterns and the uncontrollable patterns were found at a low fluence of 3 × 1014 ions/cm2 and a high fluence of 3 × 1015 ions/cm2, respectively. As a result, we could improve the surface wettability of PTFE to control the cell-adhesion property by carbon negative-ion implantation. 相似文献
119.
Nobuyuki Gokon Hiroko Murayama Jun Umeda Tsuyoshi Hatamachi Tatsuya Kodama 《International Journal of Hydrogen Energy》2009
Two-step thermochemical water-splitting using monoclinic ZrO2-supported Fe3O4 (Fe3O4/m-ZrO2) for hydrogen production was examined at high thermal reduction temperatures of 1400–1600 °C. After thermal reduction of Fe3O4/m-ZrO2, the reduced sample was quenched in liquid nitrogen, and was subsequently subjected to the water-decomposition step at 1000 °C. Quenching of the solid sample was conducted for analysis of the chemical reactions, such as phase transitions, occurring at high-temperature. The hydrogen productivity of Fe3O4 on a m-ZrO2 support and the conversion of Fe3O4 to FeO were significantly enhanced with higher thermal reduction temperatures. The Fe3O4-to-FeO conversion reached 60% when the Fe3O4/m-ZrO2 was thermally reduced at 1600 °C. The phase transition of m-ZrO2 support to tetragonal ZrO2 (t-ZrO2) did not occur during the thermal reduction at 1400–1500 °C, but it did proceed slightly at 1600 °C. Fe ions from Fe3O4 did not enter the ZrO2 lattice during high-temperature thermal reduction. Thus, the Fe3O4 loaded on a m-ZrO2 support can continuously contribute as a Fe3O4–FeO redox reactant for thermochemical water-splitting at high-temperatures of 1400–1600 °C. 相似文献
120.
Isolation and Identification of Antihypertensive Peptides from Antarctic Krill Tail Meat Hydrolysate 总被引:2,自引:0,他引:2
Akimasa Hatanaka Hiroko Miyahara Ken Ichi Suzuki Seizo Sato 《Journal of food science》2009,74(4):H116-H120
ABSTRACT: Antarctic krill ( Euphausia superba ) obtained from the huge biomass in Antarctic waters is an important food product in Japan. Antarctic krill peptide powder (AKPP) prepared from the tail meat by enzymatic hydrolysis significantly decreased the systolic blood pressure in spontaneously hypertensive rats by a single oral administration (1, 10, or 100 mg). Presumably, the effect of AKPP was through inhibition of the conversion of angiotensin, which mediates blood pressure elevation, from its inactive propeptide to the mature angiotensin. Two potent angiotensin I-converting enzyme (ACE) inhibitory peptides were isolated from AKPP by high-performance liquid chromatography (HPLC) and identified as Val-Trp (IC50 = 2.75 μg/mL; 12.9 μM) and Leu-Lys-Tyr (IC50 = 4.26 μg/mL; 10.1 μM). Val-Trp and Leu-Lys-Tyr comprised 0.025%± 0.0023% (w/w) and 0.018%± 0.0023% (w/w) of AKPP, respectively, as measured by electrospray ionization mass spectrometry (ESI-MS). The contributions of Val-Trp and Leu-Lys-Tyr to the ACE inhibitor activity of AKPP were 17.7%± 1.60% and 8.04%± 1.03%, respectively, suggesting that these 2 peptides constitute a substantial portion of the overall ACE inhibitor potential of AKPP. 相似文献