全文获取类型
收费全文 | 947篇 |
免费 | 19篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 65篇 |
综合类 | 3篇 |
化学工业 | 239篇 |
金属工艺 | 14篇 |
机械仪表 | 42篇 |
建筑科学 | 18篇 |
能源动力 | 24篇 |
轻工业 | 77篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 100篇 |
一般工业技术 | 135篇 |
冶金工业 | 143篇 |
原子能技术 | 29篇 |
自动化技术 | 79篇 |
出版年
2023年 | 11篇 |
2022年 | 12篇 |
2021年 | 26篇 |
2020年 | 9篇 |
2019年 | 17篇 |
2018年 | 21篇 |
2017年 | 11篇 |
2016年 | 14篇 |
2015年 | 19篇 |
2014年 | 29篇 |
2013年 | 47篇 |
2012年 | 31篇 |
2011年 | 54篇 |
2010年 | 33篇 |
2009年 | 24篇 |
2008年 | 38篇 |
2007年 | 33篇 |
2006年 | 29篇 |
2005年 | 31篇 |
2004年 | 21篇 |
2003年 | 31篇 |
2002年 | 23篇 |
2001年 | 19篇 |
2000年 | 15篇 |
1999年 | 25篇 |
1998年 | 58篇 |
1997年 | 35篇 |
1996年 | 20篇 |
1995年 | 19篇 |
1994年 | 20篇 |
1993年 | 18篇 |
1992年 | 12篇 |
1991年 | 11篇 |
1990年 | 8篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 8篇 |
1986年 | 10篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1982年 | 7篇 |
1981年 | 11篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 8篇 |
1974年 | 5篇 |
1971年 | 5篇 |
1970年 | 5篇 |
排序方式: 共有970条查询结果,搜索用时 46 毫秒
101.
Yoshiyuki Mizushina Yoshihiro Takahashi Yoshihiro Sato Yasuhiro Yamaguchi Toshifumi Takeuchi Isoko Kuriyama Fumio Sugawara Hiromi Yoshida 《Food chemistry》2012
During the screening of selective DNA polymerase (pol) inhibitors, we isolated two glucosyl compounds, a cerebroside (glucosyl ceramide, AS-1-4, compound 1) and a steroidal glycoside (eleutheroside A, compound 2) from soybean (Glycine max L.). Compounds 1 and 2 selectively inhibited the activity of eukaryotic pol λ in vitro, with IC50 values of 12.2 and 9.1 μM, respectively. These compounds did not influence the activities of other eukaryotic pols including those from the A-family (pol γ), B-family (pols α, δ and ε), and Y-family (pols η, ι and κ), and also showed no effect on the activity of pol β which is of the same family (X) as pol λ. The tendency for in vitro pol λ inhibition by these compounds showed a positive correlation with the in vivo suppression of TPA (12-O-tetradecanoylphorbol-13-acetate)-induced inflammation in mouse ear. These results suggest that these glucosyl compounds from soybean may be useful for their anti-inflammatory properties. 相似文献
102.
Zulkarnain A. Noorden Sougoro Sugawara Satoshi Matsumoto 《IEEJ Transactions on Electrical and Electronic Engineering》2012,7(Z1):S25-S31
The paper evaluates the essential electrical properties—capacitance and equivalent series resistance (ESR)—of hydrocarbon‐derived electrolytes for supercapacitors using galvanostatic, constant resistance charge–discharge, cyclic voltammetry, and AC impedance measurements. The electrolytes were systematically prepared from six hydrocarbon‐derived compounds, which have different carbon chains and functional groups, with the treatment of concentrated sulfuric acid (H2SO4). Both electrical properties seem to be in conformity throughout these measurements, with the longer main carbon chain compounds giving higher capacitance and lower ESR values. Comparison between these electrolytes and the typically used aqueous solutions in supercapacitor research—1M H2SO4, 5M potassium hydroxide, and 5M sodium hydroxide—showed that the produced electrolytes give the highest capacitance value up to 30 times more than that of typical aqueous solutions. It is believed that with further treatment these hydrocarbon‐derived electrolytes can potentially be used in supercapacitors as better performing electrolytes than aqueous solutions and at a relatively low cost compared to organic solutions. IEEJ Trans 2011 DOI: 10.1002/tee.21802 相似文献
103.
The effects of kind of acid and irradiation of ultraviolet light on the graft copolymerization of methyl methacrylate onto cellulose with adsorbed ceric ion were investigated. Irrespective of ultraviolet light irradiation, the amount of reduced ceric ion in the reaction systems was increased in the order HCl > HClO4 > HNO3 > H2SO4, and the number of grafts formed was increased in the order HClO4 > HNO3 > HCl > H2SO4. Thus, it was definitely observed that the graft copolymerization is affected by the kind of acid. Ultraviolet light remarkably accelerated the reduction of ceric ion adsorbed on cellulose in the various acid mediums, but decreased the efficiency of graft formation. The most favorable results for the formation of grafts were obtained in the system in which HClO4 and ultraviolet irradiation was employed. A combination of H2SO4 and ultraviolet irradiation resulted in the lowest per cent grafting and average molecular weight of grafts. It was found that H2SO4 characteristically dissolves out ceric ion adsorbed into an aqueous solution and accelerates the formation of homopolymer. 相似文献
104.
Shoji Seki Mami Iwasaki Hiroto Makino Yasuhito Yahara Yoshitaka Miyazaki Katsuhiko Kamei Hayato Futakawa Makiko Nogami Nguyen Tran Canh Tung Tatsuro Hirokawa Mamiko Tsuji Yoshiharu Kawaguchi 《International journal of molecular sciences》2022,23(7)
Intervertebral disc (IVD) diseases are common spinal disorders that cause neck or back pain in the presence or absence of an underlying neurological disorder. IVD diseases develop on the basis of degeneration, and there are no established treatments for degeneration. IVD diseases may therefore represent a candidate for the application of regenerative medicine, potentially employing normal human dermal fibroblasts (NHDFs) induced to differentiate into nucleus pulposus (NP) cells. Here, we used a three-dimensional culture system to demonstrate that ectopic expression of MYC, KLF4, NOTO, SOX5, SOX6, and SOX9 in NHDFs generated NP-like cells, detected using Safranin-O staining. Quantitative PCR, microarray analysis, and fluorescence-activated cell sorting revealed that the induced NP cells exhibited a fully differentiated phenotype. These findings may significantly contribute to the development of effective strategies for treating IVD diseases. 相似文献
105.
Sae Saigo Tabito Kino Kotaro Uchida Takuya Sugawara Lin Chen Michiko Sugiyama Kengo Azushima Hiromichi Wakui Kouichi Tamura Tomoaki Ishigami 《International journal of molecular sciences》2022,23(1)
The prorenin/renin receptor ((P)RR) is a multifunctional protein that is widely distributed in various organs. Despite intensive research for more than 20 years, this receptor has not been fully characterized. In this study, we generated mice overexpressing the tubular epithelial (P)RR gene ((P)RR-TG mice) to test the previously reported functional role of (P)RR by Ramkumar et al. in 2015 using tubular specific (P)RR KO mice. (P)RR-TG mice were maintained and analyzed in individual metabolic cages and were administered angiotensin II blocker (ARB), direct renin inhibitor (DRI), and bafilomycin, that is, vacuolar ATPase (V-ATPase) antagonist. (P)RR-TG mice were hypertensive and had alkalized urine with lower osmolality and Na+ excretion. ARB and DRI, but not bafilomycin, concurrently decreased blood pressure. Bafilomycin acidized urine of (P)RR-TG mice, or equivalently this phenomenon restored the effect of overexpressed transgene, suggesting that (P)RR functioned as a V-ATPase in renal tubules. Afterall, (P)RR-TG mice were mated with alternative renin transgenic mice (ARen2-TG), which we identified as intracellular renin previously, to generate double transgenic mice (DT-TG). Lethal renal tubular damage was observed in DT-TG mice, suggesting that intracellular renin may be a ligand for (P)RR in tubules. In summary, (P)RR did not substantially affect the tissue renin-angiotensin system (RAS) in our model of tubular specific (P)RR gene over-expression, but alternative intracellular renin may be involved in (P)RR signaling in addition to conventional V-ATPase function. Further investigations are warranted. 相似文献
106.
Yoshitaka Nakao Kiyoshi Wakimoto Katsunori Miyagi Hidenori Itoh Yosuke Sakai Hiroaki Tagashira 《Electrical Engineering in Japan》2000,131(4):19-28
In this paper, the propagation characteristics of a creepage discharge on the surface of a solid insulator with a back electrode in perfluorocarbon liquid under an impulse voltage application are investigated. The propagation process is observed in detail by means of a high‐speed schlieren optical technique, and simultaneously waveforms of a current and a charge are also measured. Consequently, the polarity effect of the streamer propagation and the positive streamer which propagates stepwise can be seen. The latter is concurrent with the sparse current pulse which corresponds to the charge step‐variation. These results are compared with ones obtained in transformer oil. © 2000 Scripta Technica, Electr Eng Jpn, 131(4): 19–28, 2000 相似文献
107.
Glycolipids from edible plant sources were accurately quantified by silica-based, normal-phase high-performance liquid chromatography
using an evaporative light-scattering detector. Five major glycolipid classes (acylated steryl glucoside, steryl glucoside,
ceramide monohexoside, monogalactosyldiacylglycerol, and digalactosyldiacylglycerol) were separated and determined with a
binary gradient system consisting of chloroform and methanol/water (95∶5, vol/vol) without any interference from other lipid
classes and pigments. The described method was applied to 48 edible plants available in Japan including cereals, legumes,
vegetables, and fruits. Examined plant species contained glycolipids in wide concentration ranges, such as 5–645 mg/100 g
tissue. 相似文献
108.
Tomoharu Suzuki Shigeru Oshio Mari Iwata Hisayo Saburi Takashi Odagiri Tadashi Udagawa Isamu Sugawara Masakazu Umezawa Ken Takeda 《Particle and fibre toxicology》2010,7(1):1-8
Background
Epidemiological studies suggest that inhalation of carbonaceous particulate matter from biomass combustion increases susceptibility to bacterial pneumonia. In vitro studies report that phagocytosis of carbon black by alveolar macrophages (AM) impairs killing of Streptococcus pneumoniae. We have previously reported high levels of black carbon in AM from biomass smoke-exposed children and adults. We therefore aimed to use a mouse model to test the hypothesis that high levels of carbon loading of AM in vivo increases susceptibility to pneumococcal pneumonia.Methods
Female outbred mice were treated with either intranasal phosphate buffered saline (PBS) or ultrafine carbon black (UF-CB in PBS; 500 μg on day 1 and day 4), and then infected with S. pneumoniae strain D39 on day 5. Survival was assessed over 72 h. The effect of UF-CB on AM carbon loading, airway inflammation, and a urinary marker of pulmonary oxidative stress was assessed in uninfected animals.Results
Instillation of UF-CB in mice resulted a pattern of AM carbon loading similar to that of biomass-smoke exposed humans. In uninfected animals, UF-CB treated animals had increased urinary 8-oxodG (P = 0.055), and an increased airway neutrophil differential count (P < 0.01). All PBS-treated mice died within 72 h after infection with S. pneumoniae, whereas morbidity and mortality after infection was reduced in UF-CB treated animals (median survival 48 h vs. 30 h, P < 0.001). At 24 hr post-infection, UF-CB treated mice had lower lung and the blood S. pneumoniae colony forming unit counts, and lower airway levels of keratinocyte-derived chemokine/growth-related oncogene (KC/GRO), and interferon gamma.Conclusion
Acute high level loading of AM with ultrafine carbon black particles per se does not increase the susceptibility of mice to pneumococcal infection in vivo. 相似文献109.
Yoshikatsu Higuchi Masayuki Sugawara Koji Onishi Masatomi Sakamoto Susumu Nakayama 《Ceramics International》2010
Electrical properties of LaxM6O12+1.5x (M = Si, Ge) as an electrolyte for solid oxide fuel cell (SOFC) have been investigated. In LaxSi6O12+1.5x and LaxGe6O12+1.5x of x = 8–11, the highest conductivities were achieved at x = 9.7 (La9.7Si6O26.55) and x = 9.0 (La9.0(GeO4)6O1.5), respectively. The conductivity of La9.0(GeO4)6O1.5 was higher than that of La9.7Si6O26.55 in a temperature region higher than 700 °C, and the conductivity (2.4 × 10−3 S cm−1) of La9.7Si6O26.55 at 400 °C was higher than that (8.3 × 10−5 S cm−1) of La9.0(GeO4)6O1.5. The power densities of SOFC (H2 | Pt | electrolyte (thickness: 1 mm) | Pt | O2) using La9.0(GeO4)6O1.5 as an electrolyte were 14.3 mW cm−2 (700 °C) and 24.0 mW cm−2 (800 °C). The corresponding SOFC using La9.7Si6O26.55 was found to work even at lower temperatures of 400 and 500 °C with power densities of 0.011 and 0.12 mW cm−2. The SOFC (H2 | Ni–Sm0.2Ce0.8O1.9 | electrolyte | Ba0.5Sr0.5Co0.8Fe0.2O2.5 | air) using 0.3 mm thickness La9.7Si6O26.55 electrolyte gave the 3.4 mW cm−2 power density at 500 °C. 相似文献
110.
Takeshi Watanabe Tomoko K. Shimizu Yoshitaka Tateyama Yousoo Kim Maki Kawai Yasuaki Einaga 《Diamond and Related Materials》2010,19(7-9):772-777
The physical and electrochemical properties of boron-doped polycrystalline diamond electrodes, prepared with various B/C ratio, i.e., 0.1%, 0.5% (BDD-A), 1% (BDD-B), and 5% (BDD-C), were investigated. Electrochemical measurements of the heavily boron-doped films (BDD-C) showed giant electric double-layer capacitance and activity which is significantly larger than BDD-A and BDD-B as well as glassy carbon electrodes. However, interestingly, actual boron concentration of BDD-C was observed to be almost the same as that of BDD-B by secondary ion mass spectroscopy (SIMS) and glow discharge optical emission spectroscopy (GDOES) analysis. It is suggested that the large capacitance is due to a few sp2-bonded carbon impurities, which was observed only in BDD-C, although the amount of the sp2-bonded nondiamond species are very small. In the present work, the reason for the interesting electrochemical properties of heavily boron-doped diamond electrodes is discussed. Furthermore, dimensional stability of the electrodes was also confirmed by conducting harsh anodic treatment. 相似文献