全文获取类型
收费全文 | 601篇 |
免费 | 7篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 20篇 |
化学工业 | 106篇 |
金属工艺 | 18篇 |
机械仪表 | 5篇 |
建筑科学 | 11篇 |
能源动力 | 26篇 |
轻工业 | 33篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 43篇 |
一般工业技术 | 124篇 |
冶金工业 | 177篇 |
原子能技术 | 11篇 |
自动化技术 | 34篇 |
出版年
2023年 | 3篇 |
2021年 | 10篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 18篇 |
2012年 | 18篇 |
2011年 | 20篇 |
2010年 | 14篇 |
2009年 | 23篇 |
2008年 | 17篇 |
2007年 | 16篇 |
2006年 | 13篇 |
2005年 | 14篇 |
2004年 | 20篇 |
2003年 | 16篇 |
2002年 | 17篇 |
2001年 | 9篇 |
2000年 | 14篇 |
1999年 | 13篇 |
1998年 | 75篇 |
1997年 | 40篇 |
1996年 | 30篇 |
1995年 | 14篇 |
1994年 | 13篇 |
1993年 | 17篇 |
1992年 | 7篇 |
1991年 | 8篇 |
1989年 | 6篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 9篇 |
1985年 | 9篇 |
1984年 | 10篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 3篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1972年 | 3篇 |
1970年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有610条查询结果,搜索用时 15 毫秒
151.
Motomichi Doi Tadashi Nemoto Hiroshi Nakanishi Yasumasa Kuwahara Yuzuru Oguma 《Journal of chemical ecology》1997,23(8):2067-2078
To identify sex pheromone components in Drosophila ananassae, the cuticular hydrocarbons were analyzed and bioassayed. After silicic acid and two silver nitrate–silicic acid chromatographic steps, active fractions containing (Z,Z)-5,25- and (Z,Z)-4,26-hentriacontadiene as the most abundant components were obtained. Both hydrocarbons could elicit male courtship behavior. The former was the more predominant compound and elicited a higher courtship index value than the latter. Cuticular hydrocarbon differences between D. ananassae and its close relative, D. pallidosa, and their roles in species recognition are discussed. 相似文献
152.
Dr. Qin Zhu Dr. Matthew L. Hillwig Prof. Dr. Yohei Doi Prof. Dr. Xinyu Liu 《Chembiochem : a European journal of chemical biology》2016,17(6):466-470
The anion promiscuity of a newly discovered standalone aliphatic halogenase WelO5 was probed and enabled the selective synthesis of 13R‐bromo‐12‐epi‐fischerindole U via late‐stage enzymatic functionalization of an unactivated sp3 C?H bond. Pre‐saturating the WelO5 active site with a non‐native bromide anion was found to be critical to the highly selective in vitro transfer of bromine, instead of chlorine, to the target carbon center and also allowed the relative binding affinity of bromide and chloride towards the WelO5 enzyme to be assessed. This study further revealed the critical importance of halogen substitution on modulating the antibiotic activity of fischerindole alkaloids and highlights the promise of WelO5‐type aliphatic halogenases as enzymatic tools to fine‐tune the bioactivity of complex natural products. 相似文献
153.
DNA electronic devices were prepared on silicon-based three-terminal electrodes. Both ends of DNA molecules (400 bp long, mixed sequences) were bridged via chemical bonds between the source-drain nanogap (120 nm) electrodes. S-Shaped I-V curves were obtained and the electric current can be modulated by the gate voltage. The DNA molecules act as semiconducting p-type nanowires in the three-terminal device. 相似文献
154.
Lakshmi Sharma Yoshino Ogino Toshiji Kanaya Tadahisa Iwata Yoshiharu Doi 《大分子材料与工程》2004,289(12):1068-1073
Summary: Polyhydroxybutyrate (PHB) is an ideal bioplastic, however, this polymer undergoes a severe embrittlement process because of its spherulitic structure, rendering the material brittle. Using a series of in‐situ rheo techniques, we have previously observed only the rapid initial stage of shish formation, we term a partial shish, which existed at high shears in medium‐molecular‐weight PHB, = 360 000. The shish kebab morphology is anticipated to remove or severely lessen this embrittlement process whilst providing new properties and applications. For medium and ultra high‐molecular‐weight (MMWT, = 360 000/UHMWT, = 5 × 106) PHB 99/1 and 99.5/0.5 blends only a partial shish is identified. However, the initial shish formation stage and subsequent stages were observed at 98/2 and 97/3 blend ratios resulting in a complete shish, we term the full shish, and fiber formation was evident. We believe this fiber morphology achieved by high molecular weights is crucial to sustaining the shish kebab structure for an excessive period.
155.
Yoshihiro Kusano Akira Doi Minoru Fukuhara Makoto Nakanishi Tatsuo Fujii Jun Takada Yasunori Ikeda Mikio Takano Catherine Henrist Rudi Cloots ré Rulmont Marcel Ausloos 《Journal of the American Ceramic Society》2009,92(8):1840-1844
The effects of oxygen partial pressure during thermal treatment on the color and microstructure of Bizen, a traditional Japanese stoneware, were studied through model experiments using clay pellets covered lightly with rice straw as a coloring assistant. When heated in flowing nitrogen, the model pellet turned blackish owing to the formation of α-Fe particles coated with graphite. However, schreibersite (Fe3 P), which is also blackish, was formed specifically on the pellet surface in direct contact with the straw. The rice straw seems to have generated a strongly reducing atmosphere, strong enough for the metallization to α-Fe, and also to have provided phosphorus through contact. When oxygen content in the surrounding gas atmosphere was raised to N2 /O2 =99/1, the pellet surface turned yellowish brown because the main coloring material was Fe3+ -containing mullite. At oxygen contents of N2 /O2 =98/2 or more, the formation of hematite (α-Fe2 O3 ) pushed the color to deep red. 相似文献
156.
This paper presents the experimental results of a robust control scheme to suppress the vibration of a flexible structure. The feedback controller is designed using the H∞-based robust control theory. For this purpose, a flexible bridge tower connected with a crane structure is considered to control its first five vibration modes using a static state feedback controller. A five-degrees-of-freedom reduced-order lumped parameter mass model is derived by neglecting high-frequency vibration modes. The neglected vibration modes constitute the unstructured system uncertainties. An attempt has been made to reduce the unmodeled uncertainties by placing actuators and/or sensors at the node points of a neglected mode. The H ∞-based control law is able to suppress the low-order vibration modes without any spillover instability due to neglected modes. The proposed control scheme is also shown to be robust against parameter variations. The performance of the control scheme is verified both by simulation and experimental studies 相似文献
157.
A. Doi 《Journal of Materials Science》2007,42(3):1031-1036
The electrical response of an ion-conducting glass to dc biasing was very sensitive to the anode material and anode–glass
interface, especially when biasing was made under high electric field at high temperature. The response of the platinum-anoded
AgPO3 glass was studied, and was compared with that of the gold-anoded one. Emphasis was laid on the effect of polishing of the
glass surface. 相似文献
158.
Toshiyuki Doi 《Vacuum》2009,84(5):734-737
The unsteady motion of a rarefied gas between two parallel plates, one of which is oscillating in its plane, is studied based on the linearized Boltzmann equation for a hard sphere molecular gas. The detailed numerical solution for a wide range of gas rarefaction and oscillatory frequency is presented. The transition of the solution from low to high frequencies under various degrees of gas rarefaction is discussed. 相似文献
159.
160.
Doi T Matsunaga S Maeno E Tsuchiya K Higashi T Misawa S Uchiyama S Ooi T Nakao M Fukui K 《Journal of Bioscience and Bioengineering》2004,98(4):304-305
The minimum size of a closed nano-space in which cells can survive was determined using 4-nl nanowells. One or two cells could divide in the nanowell. Our results suggest that the cell division activity in the nano-space is determined by the conflict between intercellular effects and consumption of substrates. 相似文献