全文获取类型
收费全文 | 651篇 |
免费 | 14篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 38篇 |
化学工业 | 167篇 |
金属工艺 | 18篇 |
机械仪表 | 8篇 |
建筑科学 | 24篇 |
矿业工程 | 2篇 |
能源动力 | 23篇 |
轻工业 | 44篇 |
水利工程 | 2篇 |
无线电 | 61篇 |
一般工业技术 | 97篇 |
冶金工业 | 134篇 |
原子能技术 | 9篇 |
自动化技术 | 39篇 |
出版年
2023年 | 2篇 |
2022年 | 14篇 |
2021年 | 16篇 |
2020年 | 5篇 |
2019年 | 10篇 |
2018年 | 12篇 |
2017年 | 8篇 |
2016年 | 15篇 |
2015年 | 12篇 |
2014年 | 21篇 |
2013年 | 25篇 |
2012年 | 20篇 |
2011年 | 27篇 |
2010年 | 20篇 |
2009年 | 26篇 |
2008年 | 20篇 |
2007年 | 24篇 |
2006年 | 20篇 |
2005年 | 16篇 |
2004年 | 14篇 |
2003年 | 25篇 |
2002年 | 14篇 |
2001年 | 13篇 |
2000年 | 8篇 |
1999年 | 15篇 |
1998年 | 48篇 |
1997年 | 35篇 |
1996年 | 17篇 |
1995年 | 18篇 |
1994年 | 16篇 |
1993年 | 19篇 |
1992年 | 11篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 10篇 |
1986年 | 9篇 |
1985年 | 5篇 |
1984年 | 10篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1979年 | 3篇 |
1978年 | 6篇 |
1977年 | 2篇 |
1976年 | 5篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1970年 | 2篇 |
排序方式: 共有666条查询结果,搜索用时 15 毫秒
11.
Hideaki Adachi Toshifumi Satoh Masahiro Sakai Koichi Mizuno Kentaro Setsune 《Journal of Superconductivity》1994,7(4):737-741
Epitaxial multilayer thin films of infinite-layer (Sr, Ca)CuO2 and perovskite (Sr, Ca)RuO3 have been prepared on (100) SrTiO3 substrates by multitarget rf magnetron sputtering. X-ray diffraction analyses revealed that the multilayer structure of (Sr, Ca)CuO3/(Sr, Ca)RuO3 was successfully fabricated with a minimum layer thickness of 20 Å. Transmission electron microscopy measurements of the multilayers indicated that there was no dislocation which normally exists in single-layer films with an infinite-layer structure. Resistivities of multilayer films at room temperature ranged from 1 to 10 m cm and showed semiconductor-like dependence against the temperature. 相似文献
12.
Ryu-ichiro Tanaka Katsuhisa Sakaguchi Shinjiro Umezu 《Artificial Life and Robotics》2017,22(3):316-320
Gelatin is useful for biofabrication, because it can be used for cell scaffolds and it has unique properties. Therefore, we attempted to fabricate biodevices of gelatin utilizing micro 3D printer which is able to print with high precision. However, it has been difficult to fabricate 3D structure of gelatin utilizing 3D printer, because a printed gelatin droplet on the metal plate electrode would spread before solidification. To clear this problem, we developed a new experimental set-up with a peltier device that can control temperature of the impact point. At an impact point temperature of 80 °C, the spreading of printed gelatin droplets was prevented. Therefore, we were able to print a ball gelatin. In addition, we were able to print a narrower gelatin line than at an impact point temperature of 20 °C. 相似文献
13.
The purpose of this study was to characterize the oxide scales formed on various Cr-Si-Ni compacts at 1273 K in air and H2O-containing atmosphere by TEM. It was found that CrSi2-(5-20)mass%Ni compacts form double layer scales, consisting of an outer Cr2O3 layer and an inner SiO2 layer. The oxide scale changed from SiO2- to Cr2O3-based scale with an increase in the Ni concentration. However, it was observed that the oxide scale formed in H2O-containing atmospheres showed local SiO2 growth into the substrate. This result suggests that the inward oxidant diffusion promotes the local growth of SiO2 in the H2O-containing atmospheres. 相似文献
14.
Stabilization of a Power System Including Inverter‐Type Distributed Generators by a Virtual Synchronous Generator 下载免费PDF全文
The capacity of distributed generators (DGs) connected to the grid by inverters is growing year after year. The inverters are generally controlled by a phase locked loop (PLL) in order to achieve synchronization with the power system frequency. Power systems may become unstable as the capacity of the inverter‐type DGs continues to increase, because the inverter frequency is controlled just to follow the frequency determined by other synchronous generators. It has been suggested that inverters be controlled to behave like a synchronous generator. This concept is referred to as the virtual synchronous generator (VSG). In this paper, a control scheme for a VSG is presented, and the design method for the required energy storage and the capacity for grid stabilization control by a VSG is investigated by computer simulations. 相似文献
15.
Effects of extrusion ratio (ER) during extruding on mechanical properties of poly(lactic acid) (PLA) screws were investigated in terms of shear and twist strength. Shear strength increased by drawing, while twist strength decreased. This might be due to orientation of molecular chains during drawing. In order to evaluate orientation of molecular chains, orientation function in extruded billets was measured as a function of ER. Since orientation function increased with ER, drawing is effective method to improve shear strength of screw, where fibrous structure which was formed during extruding resisted shear stress in cross-section perpendicular to screw axis. Although orientation functions for billet extruded at ER 1.3–4 were equivalent, both strengths changed for the screw extruded at the range of this ER. Infrared spectra suggested transforming from α to β crystal for the billet extruded at the range of this ER. This result suggested that mechanical properties of screw also depended on the crystal forms. 相似文献
16.
Duchenne muscular dystrophy (DMD) is an X-linked recessive neuromuscular disorder with a prevalence of approximately 1 in 3500–5000 males. DMD manifests as childhood-onset muscle degeneration, followed by loss of ambulation, cardiomyopathy, and death in early adulthood due to a lack of functional dystrophin protein. Out-of-frame mutations in the dystrophin gene are the most common underlying cause of DMD. Gene editing via the clustered regularly interspaced short palindromic repeats (CRISPR) system is a promising therapeutic for DMD, as it can permanently correct DMD mutations and thus restore the reading frame, allowing for the production of functional dystrophin. The specific mechanism of gene editing can vary based on a variety of factors such as the number of cuts generated by CRISPR, the presence of an exogenous DNA template, or the current cell cycle stage. CRISPR-mediated gene editing for DMD has been tested both in vitro and in vivo, with many of these studies discussed herein. Additionally, novel modifications to the CRISPR system such as base or prime editors allow for more precise gene editing. Despite recent advances, limitations remain including delivery efficiency, off-target mutagenesis, and long-term maintenance of dystrophin. Further studies focusing on safety and accuracy of the CRISPR system are necessary prior to clinical translation. 相似文献
17.
18.
K Sakaguchi JE Herrera S Saito T Miki M Bustin A Vassilev CW Anderson E Appella 《Canadian Metallurgical Quarterly》1998,12(18):2831-2841
19.
H Uchiyama T Obata T Tsubaki N Sakaguchi Y Iikura T Aoki 《Canadian Metallurgical Quarterly》1995,44(2):70-76
In our Department, continuous isoproterenol inhalation therapy has been conducted on status asthmatics over the last 10 years. In the present study, we investigated whether there are any differences in the therapeutic efficacy of continuous inhalation of isoproterenol in the presence or absence of respiratory infections which may induce or aggravate asthma attacks. The treatment period was significantly longer in patients with pneumonia. Further prolongation of the treatment period was noted in patients with atelectasis. However, there were no apparent differences in therapeutic efficacy according to age or the severity of attacks. These findings suggest that continuous inhalation of isoproterenol is very effective for status asthmatics if respiratory infections are thoroughly controlled. 相似文献
20.