全文获取类型
收费全文 | 2455篇 |
免费 | 79篇 |
国内免费 | 12篇 |
专业分类
电工技术 | 34篇 |
综合类 | 2篇 |
化学工业 | 452篇 |
金属工艺 | 61篇 |
机械仪表 | 86篇 |
建筑科学 | 49篇 |
矿业工程 | 2篇 |
能源动力 | 147篇 |
轻工业 | 163篇 |
水利工程 | 33篇 |
石油天然气 | 5篇 |
无线电 | 292篇 |
一般工业技术 | 589篇 |
冶金工业 | 305篇 |
原子能技术 | 21篇 |
自动化技术 | 305篇 |
出版年
2023年 | 35篇 |
2022年 | 85篇 |
2021年 | 106篇 |
2020年 | 91篇 |
2019年 | 74篇 |
2018年 | 118篇 |
2017年 | 89篇 |
2016年 | 84篇 |
2015年 | 57篇 |
2014年 | 75篇 |
2013年 | 150篇 |
2012年 | 88篇 |
2011年 | 121篇 |
2010年 | 93篇 |
2009年 | 68篇 |
2008年 | 68篇 |
2007年 | 95篇 |
2006年 | 49篇 |
2005年 | 50篇 |
2004年 | 53篇 |
2003年 | 33篇 |
2002年 | 39篇 |
2001年 | 31篇 |
2000年 | 24篇 |
1999年 | 31篇 |
1998年 | 74篇 |
1997年 | 68篇 |
1996年 | 47篇 |
1995年 | 29篇 |
1994年 | 28篇 |
1993年 | 35篇 |
1992年 | 26篇 |
1991年 | 30篇 |
1990年 | 15篇 |
1989年 | 20篇 |
1988年 | 16篇 |
1987年 | 18篇 |
1986年 | 25篇 |
1985年 | 16篇 |
1984年 | 22篇 |
1983年 | 21篇 |
1982年 | 18篇 |
1981年 | 18篇 |
1980年 | 28篇 |
1979年 | 16篇 |
1978年 | 20篇 |
1977年 | 24篇 |
1976年 | 39篇 |
1975年 | 17篇 |
1973年 | 17篇 |
排序方式: 共有2546条查询结果,搜索用时 31 毫秒
1.
2.
3.
Yang Chao-Tung Chen Shuo-Tsung Liu Jung-Chun Chan Yu-Wei Chen Chien-Chih Verma Vinod Kumar 《The Journal of supercomputing》2019,75(8):4408-4429
The Journal of Supercomputing - In the last decade, cloud computing has brought enormous changes to people’s lives. Cloud computing gives a client-driven computational model. In this case,... 相似文献
4.
In India, little attention has been paid on antimicrobial resistance (AMR) in the context of developing “One Health” approach. Hence, utilizing multi-disciplinary approach, we assess the AMR level and dynamics/pattern of multi-drug resistance (MDR) in Escherichia coli, Salmonella spp., and Staphylococcus aureus circulating over the different stages of poultry in India. A total of 342 isolates including E. coli (n = 143), Salmonella spp. (n = 104), and S. aureus (n = 95) were recovered from fecal (n = 80) and cecal (n = 80) samples of chicken, collected across the different poultry-retail shops and poultry-farms located at urban and rural areas of Rajasthan, India, respectively. High rates of AMR to drugs that are critically/highly important both in human and veterinary medicine were observed among all the isolates. Upward trends in AMR prevalence was observed in poultry-retail shops than in poultry-farms. Notably, >90% of all the isolates were MDR, of particular, pattern/prevalence of MDR was substantially varied across the poultry-farms vs. poultry-retail shops. Our results indicate AMR including MDR to be common in E. coli, Salmonella spp., and S. aureus distributed frequently in poultry. The study encourages the formulation of national policy, programmes and further research with a “One Health” approach that can benefits to the human/animal and the environment. 相似文献
5.
A new and simple method of finite-element grid improvement is presented. The objective is to improve the accuracy of the analysis. The procedure is based on a minimization of the trace of the stiffness matrix. For a broad class of problems this minimization is seen to be equivalent to minimizing the potential energy. The method is illustrated with the classical tapered bar problem examined earlier by Prager and Masur. Identical results are obtained. 相似文献
6.
Jon T. Carter Paul E. Krajewski Ravi Verma 《JOM Journal of the Minerals, Metals and Materials Society》2008,60(11):77-81
The hot blow forming of magnesium sheet offers significant opportunity for forming complex, lightweight parts for automotive
applications. This paper characterizes the elevated-temperature formability of AZ31 magnesium sheet materials and the effect
of processing conditions on the performance of these materials. In addition, magnesium sheet application development at General
Motors Corporation is reviewed. 相似文献
7.
We report on the use of pulsed plasma-enhanced chemical vapor deposition (P-PECVD) technique and show that “state-of-the-art” amorphous silicon (a-Si:H) materials and solar cells can be produced at a deposition rate of up to 15 Å/s using a modulation frequency in the range 1–100 kHz. The approach has also been developed to deposit materials and devices onto large area, 30 cm×40 cm, substrates with thickness uniformity (<5%), and gas utilization rate (>25%). We have developed a new “hot wire” chemical vapor deposition (HWCVD) method and report that our new filament material, graphite, has so far shown no appreciable degradation even after deposition of 500 μm of amorphous silicon. We report that this technique can produce “state-of-the-art” a-Si:H and that a solar cell of p/i/n configuration exhibited an initial efficiency approaching 9%. The use of microcrystalline silicon (μc-Si) materials to produce low-cost stable solar cells is gaining considerable attention. We show that both of these techniques can produce thin film μc-Si, dependent on process conditions, with 1 1 1 and/or 2 2 0 orientations and with a grain size of approx. 500 A. Inclusion of these types of materials into a solar cell configuration will be discussed. 相似文献
8.
The application of micro- and nanofabrication processes to the development of hybrid synthetic and biological systems may enable the production of new devices such as controllable transporters, gears, levers, micropumps, or microgenerators powered by biological molecular motors. However, engineering these hybrid devices requires fabrication processes that are compatible with biological materials such as kinesin motor proteins and microtubules. In this paper, the effects of micro- and nanofabrication processing chemicals and resists on the functionality of casein, kinesin, and microtubule proteins are systematically examined to address the important missing link of the biocompatibility of micro- and nanofabrication processes needed to realize hybrid system fabrication. It is found that both casein, which is used to prevent motor denaturation on surfaces, and kinesin motors are surprisingly tolerant of most of the processing chemicals examined. Microtubules, however, are much more sensitive. Exposure to the processing chemicals leads to depolymerization, which is partially attributed to the pH of the solutions examined. When the chemicals were diluted in aqueous buffers, a subset of them no longer depolymerized microtubules and in their diluted forms still worked as resist removers. This approach broadens the application of micro- and nanofabrication processes to hybrid synthetic and biological system fabrication. 相似文献
9.
Practical Equivalent Continuum Model for Simulation of Jointed Rock Mass Using FLAC3D 总被引:1,自引:0,他引:1
A simple practical equivalent continuum numerical model for simulating the behavior of jointed rock mass has been extended to three-dimensional using FLAC3D. This model estimates the properties of jointed rock mass from the properties of intact rock and a joint factor (Jf), which is the integration of the properties of joints to take care of the effects of frequency, orientation, and strength of joint. A new FISH function has been written in FLAC3D specifically for modeling jointed rocks using the Duncan and Chang hyperbolic model. This model has been validated first with simple element tests at different confining pressures for different rocks with different joint configurations. Explicit modeling of the joints has also been done in element tests and results obtained compare well with the results of equivalent continuum model and also with experimental results. Further, this has been applied for a case study of a large underground power house cavern in the Himalayas. The analysis has been done under various stages of excavation, assigning a null model available in FLAC3D for simulating the excavation. 相似文献
10.
Higher resolution can be achieved in lithography by decreasing the wavelength of the exposure source. However, resist material
and their processing are also important when we move to a shorter wavelength lithography technology. This paper reviews the
recent development and challenges of deep-UV photoresists and their processing technology. 相似文献