全文获取类型
收费全文 | 960篇 |
免费 | 29篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 65篇 |
综合类 | 5篇 |
化学工业 | 301篇 |
金属工艺 | 20篇 |
机械仪表 | 33篇 |
建筑科学 | 18篇 |
能源动力 | 54篇 |
轻工业 | 98篇 |
水利工程 | 1篇 |
无线电 | 28篇 |
一般工业技术 | 203篇 |
冶金工业 | 70篇 |
原子能技术 | 39篇 |
自动化技术 | 56篇 |
出版年
2023年 | 4篇 |
2022年 | 11篇 |
2021年 | 19篇 |
2020年 | 8篇 |
2019年 | 16篇 |
2018年 | 5篇 |
2017年 | 17篇 |
2016年 | 17篇 |
2015年 | 13篇 |
2014年 | 22篇 |
2013年 | 50篇 |
2012年 | 31篇 |
2011年 | 58篇 |
2010年 | 50篇 |
2009年 | 61篇 |
2008年 | 44篇 |
2007年 | 42篇 |
2006年 | 41篇 |
2005年 | 35篇 |
2004年 | 42篇 |
2003年 | 36篇 |
2002年 | 37篇 |
2001年 | 24篇 |
2000年 | 23篇 |
1999年 | 24篇 |
1998年 | 26篇 |
1997年 | 21篇 |
1996年 | 24篇 |
1995年 | 20篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1992年 | 9篇 |
1991年 | 15篇 |
1990年 | 10篇 |
1989年 | 12篇 |
1988年 | 15篇 |
1987年 | 6篇 |
1986年 | 11篇 |
1985年 | 7篇 |
1984年 | 8篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1973年 | 3篇 |
1970年 | 2篇 |
排序方式: 共有991条查询结果,搜索用时 0 毫秒
71.
Hiromi?YoshidaEmail author Kyoko?Matsuda Yuki?Hirakawa Yoshiyuki?Mizushina 《Journal of the American Oil Chemists' Society》2003,80(7):665-674
To clarify the effects of microwave roasting on the distribution of tocopherols and FA of phospholipids within soybeans, whole
soybeans (Glycine max) were treated by microwave and further evaluted as compared to a raw sample. Tocopherol homologs, measured using HPLC, and
phospholipid profiles, quantified with GC, were determined in the seed coat, the embryonic axis, and selections of cotyledons
separated from three cultivars. The tocopherols were predominantly detected in the axis, followed by the cotyledons, and then
very little in the coat. As much as 25% of the individual tocopherols originally present in the coat were lost at 12 min of
roasting, whereas <25% was lost in the cotyledons and the axis after 20 min of roasting. The greatest rate of phospholipid
loss (P<0.05) was observed in PE, followed by PC and PI, and their changing patterns were more pronounced in the coat than in the
cotyledons or the axis. Thus, tocopherol content and phospholipid profiles change with microwave roasting according to tissue. 相似文献
72.
Che-Jui Yeh Chiao-Chu Ku Wei-Chen Lin Chiao-Yuan Fan Prof. Dr. Medel Manuel L. Zulueta Dr. Yoshiyuki Manabe Prof. Dr. Koichi Fukase Prof. Dr. Yaw-Kuen Li Prof. Dr. Shang-Cheng Hung 《Chembiochem : a European journal of chemical biology》2019,20(2):237-240
Many circulating cancer-related proteins, such as fibroblast growth factors (FGFs), associate with glycosaminoglycans—particularly heparan sulfate—at the cell surface. Disaccharide analogues of heparan sulfate had previously been identified as the shortest components out of the sugars that bind to FGF-1 and FGF-2. Taking note of the typical pose of l -iduronic acid, we conceived of per-O-sulfonated analogues of such disaccharides, and devised a single-step procedure for per-O-sulfonation of unprotected sugars with concomitant 1,6-anhydro bridge formation to achieve such compounds through direct use of SO3 ⋅ Et3N as sulfonation reagent and dimethylformamide as solvent. The synthesized sugars based on the oligomaltose backbone bound FGF-1 and FGF-2 mostly at the sub-micromolar level, although the tetrasaccharide analogue achieved low-nanomolar binding with FGF-2. 相似文献
73.
Daisuke Yamanaka Suzuka Kurita Yuka Hanayama Yoshiyuki Adachi 《International journal of molecular sciences》2021,22(4)
β-Glucan is widely distributed in various plants and microorganisms and is composed of β-1,3-linked d-glucose units. It may have a branched short or long side chain of glucose units with β-1,6- or β-1,4-linkage. Numerous studies have investigated different β-glucans and revealed their bioactivities. To understand the structure-function relationship of β-glucan, we constructed a split-luciferase complementation assay for the structural analysis of long-chain β-1,6-branched β-1,3-glucan. The N- and C-terminal fragments of luciferase from deep-sea shrimp were fused to insect-derived β-1,3-glucan recognition protein and fungal endo-β-1,6-glucanase (Neg1)-derived β-1,6-glucan recognition protein, respectively. In this approach, two β-glucan recognition proteins bound to β-glucan molecules come into close proximity, resulting in the assembly of the full-length reporter enzyme and induction of transient luciferase activity, indicative of the structure of β-glucan. To test the applicability of this assay, β-glucan and two β-glucan recognition proteins were mixed, resulting in an increase in the luminescence intensity in a β-1,3-glucan with a long polymer of β-1,6-glucan in a dose-dependent manner. This simple test also allows the monitoring of real-time changes in the side chain structure and serves as a convenient method to distinguish between β-1,3-glucan and long-chain β-1,6-branched β-1,3-glucan in various soluble and insoluble β-glucans. 相似文献
74.
通过一个足尺的2层木结构房屋振动台试验,对Hilbert-Huang变换(HHT)在结构损伤诊断中的应用进行了研究与分析。在简要介绍了Hilbert-Huang变换的基本原理与方法后,根据在振动台试验中获取的结构反应数据,利用Hilbert-Huang变换对结构的动力特性及损伤状况进行了诊断。分析结果表明,Hilbert-Huang变换能有效地将隐含在实测结构反应信号中的结构动力特性与损伤信息进行提取,从而能对结构的健康状况进行诊断。 相似文献
75.
Yusuke Kusuda Kinya Fukuda Masao Matsumura Kazuhisa Hagisawa Gaku Okamoto Tatsuo Nakanishi Yoshiyuki Inoue 《Electrical Engineering in Japan》2007,159(4):18-26
Recently, composite insulators have been increasingly employed mainly for economic reasons. We have developed a new type of outdoor termination using a composite insulator, which can be installed horizontally on a steel tower in order to reduce the construction cost. In this outdoor termination, SF6 gas is filled in the composite insulator and a cold shrinkable premolded rubber unit is applied instead of the combined use of a rubber‐molded stress relief cone, epoxy resin insulator and spring unit. The application of the composite insulator, SF6 gas and cold shrinkable premolded rubber unit reduces the total weight and makes it possible to install the termination horizontally on the tower. The new‐type outdoor termination for 77‐kV XLPE cable has already been applied in commercial use and enabled a reduction of the construction costs for power transmission lines. A 154‐kV new‐type outdoor termination has been developed and its initial electrical tests were successfully completed. This paper describes the design and performance of both 77‐kV and 154‐kV new‐type outdoor termination, and a follow‐up survey of the 77‐kV new termination in a commercial use. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(4): 18– 26, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20511 相似文献
76.
Mohammad Khazaei Mohammad Saeed Bahramy Ahmad Ranjbar Hiroshi Mizuseki Yoshiyuki Kawazoe 《Carbon》2009,47(14):3306-81
Recent scanning tunneling microscopy (STM) experiments display images with star and ellipsoidal like features resulting from unique geometrical arrangements of a few adsorbed hydrogen atoms on graphite. Based on first-principles STM simulations, we have found that the model with three hydrogen atoms, in which the hydrogen atoms are symmetrically placed on the graphene sheet in an equilateral triangle, encompassing a complete hexagon ring of carbon atoms, reproduces the experimentally observed starlike STM patterns. Additionally, we confirm that an ortho-hydrogen pair is the configuration corresponding to the ellipsoidal images. These calculations reveal that when the hydrogen pairs are in the same orientation, they are energetically more stable. 相似文献
77.
78.
79.
In a distribution system containing a step voltage regulator (SVR), the maximum capacity of distributed generators (DGs) is calculated for DGs completely dispersed on a distribution line. The maximum capacity of the DGs is calculated under the constraint of an upper or lower voltage regulation value and an allowable current value by using voltage and current profiles expressed analytically in terms of our proposed power density model. As the voltage control method for the SVRs, we consider the conventional SVR, whose transformation ratio is fixed to 1 if it detects reverse power flow, and a reverse power flow SVR which operates appropriately even if it detects reverse power flow. Calculation of the maximum capacity of DGs with respect to the power factor of the DGs indicates which parameters, including the power factor of the DGs, the distribution of the DGs, and the load, influence the maximum DG capacity. Calculation of the maximum capacity of DGs versus the system length indicates that the constraints can be subdivided into two modes in the conventional SVR and four modes in the reverse power flow SVR. The maximum DG capacity in the system with a reverse power flow SVR is larger than that in a system with the conventional SVR. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(4): 41–51, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20591 相似文献
80.
Yoshiyuki Tomita 《Metallurgical and Materials Transactions A》1987,18(8):1495-1501
A modified heat treatment has been suggested whereby lower temperature plane-strain fracture toughness (K
IC) of 4340 ultrahigh strength steel is dramatically improved in developed strength and Charpy impact energy levels. The modified
heat-treated 4340 steel (MHT-4340 steel) consists of a mixed structure of martensite and about 25 vol pct lower bainite which
appears in acicular form and partitions prior austenite grains. This is produced through isothermal transformation at 593
K for a short time followed by an oil quench (after austenitizing at 1133 K and subsequent interrupted quenching in a lead
bath at 823 K). The mechanical properties obtained at room temperature (293 K) and 193 K have been compared with those achieved
using various heat treatments. Significant conclusions are as follows: the MHT-4340 steel compared to the 1133 K directly
oil-quenched 4340 steel increased theK
IC values by 15 to 20 MPa • m1/2 at increased strength and Charpy impact energy levels regardless of the test temperature examined. At 193 K,K
IC values of the MHT-4340 steel were not less than those of the 1473 K directly oil-quenched 4340 steel, in whichK
IC values are significantly enhanced at markedly increased strength, ductility, and Charpy impact energy levels. The MHT-4340
steels compared to austempered 4340 steels at 593 K, which have excellent Charpy impact properties, showed superiorK
IC values at significant increased strength levels irrespective of test temperatures. The lower temperature improvement inK
IC can be attributed to not only the crack-arrest effect by acicular lower bainite but also to the stress-relief effect by the
lower bainite just ahead of the current crack. 相似文献