全文获取类型
收费全文 | 1610篇 |
免费 | 157篇 |
国内免费 | 14篇 |
专业分类
电工技术 | 44篇 |
综合类 | 8篇 |
化学工业 | 427篇 |
金属工艺 | 73篇 |
机械仪表 | 62篇 |
建筑科学 | 82篇 |
矿业工程 | 4篇 |
能源动力 | 125篇 |
轻工业 | 130篇 |
水利工程 | 25篇 |
石油天然气 | 21篇 |
无线电 | 167篇 |
一般工业技术 | 242篇 |
冶金工业 | 73篇 |
原子能技术 | 16篇 |
自动化技术 | 282篇 |
出版年
2024年 | 5篇 |
2023年 | 35篇 |
2022年 | 55篇 |
2021年 | 99篇 |
2020年 | 81篇 |
2019年 | 103篇 |
2018年 | 144篇 |
2017年 | 132篇 |
2016年 | 152篇 |
2015年 | 85篇 |
2014年 | 110篇 |
2013年 | 182篇 |
2012年 | 120篇 |
2011年 | 89篇 |
2010年 | 78篇 |
2009年 | 57篇 |
2008年 | 42篇 |
2007年 | 32篇 |
2006年 | 19篇 |
2005年 | 9篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 13篇 |
2001年 | 11篇 |
2000年 | 8篇 |
1999年 | 4篇 |
1998年 | 13篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 12篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1979年 | 3篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1970年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有1781条查询结果,搜索用时 15 毫秒
71.
72.
Improved physical stability of docosahexaenoic acid and eicosapentaenoic acid encapsulated using nanoliposome containing α‐tocopherol 下载免费PDF全文
Mohammad Ali Sahari Hamid Reza Moghimi Zahra Hadian Mohsen Barzegar Abdoreza Mohammadi 《International Journal of Food Science & Technology》2016,51(5):1075-1086
This study aimed to develop a nanoliposomal formulation containing α‐tocopherol loaded with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and to characterise the formulation by its physical stability. For this purpose, different nanoliposomal formulations with dipalmitoyl phosphocholine were prepared using a modified thin‐film hydration method and evaluated by particle size, polydispersity index (PDI), transmission electron microscopy, differential scanning calorimetry and determining the encapsulation efficiencies of DHA and EPA. A physical stability study was conducted by investigating the change in the vesicle encapsulation efficiency, particle size, PDI and shape when stored at 4, 30 and 40 °C for 3 months. High encapsulation efficiency of DHA and EPA (89.1% ± 0.6% and 81.9% ± 1.4%) and appropriate particle size (82 ± 0.8 nm) were obtained for liposomes composed of α‐tocopherol. The optimum formulation was stable for 90 days when kept at 4 °C. This study demonstrated that α‐tocopherol had a protective effect on the physical stability of the nanoliposomes containing DHA and EPA. 相似文献
73.
Mohsen Darman 《Journal of Modern Optics》2017,64(18):1839-1845
We introduce a new compact noise equivalent circuit model of semiconductor lasers (SLs) from the rate equation including Langevin noise sources. The noise sources are described in terms of the spectral properties of the relative intensity noise (RIN) and frequency/phase noise (FN). Unlike the previous noise equivalent circuit models, which are based on two different DC and small-signal circuit models, using only a single circuit model, the static and dynamic responses and also the noise characteristics of SLs, can be investigated. We examine the validity of the presented noise circuit model by comparing the simulated results with the analytical and numerical results available in the literatures. 相似文献
74.
Mohsen Torabi Hessameddin Yaghoobi Karem Boubaker 《International Journal of Thermophysics》2013,34(1):122-138
With the advent of temperatures near absolute zero, it is often claimed that at very low temperatures the effect of thermal wave propagation must be included by the hyperbolic heat conduction equation (HHCE). In this paper the non-linear convective–radiative HHCE is investigated. Opposite to common numerical analyses, analytical expressions are obtained for the temperature variations by the multi-step differential transformation method. Some conclusions about alteration of the specific heat of the material, temperature steeping, and Vernotte number have been formulated. 相似文献
75.
Bohumir Jelinek Mohsen Eshraghi Sergio Felicelli John F. Peters 《Computer Physics Communications》2014
An extremely scalable lattice Boltzmann (LB)–cellular automaton (CA) model for simulations of two-dimensional (2D) dendritic solidification under forced convection is presented. The model incorporates effects of phase change, solute diffusion, melt convection, and heat transport. The LB model represents the diffusion, convection, and heat transfer phenomena. The dendrite growth is driven by a difference between actual and equilibrium liquid composition at the solid–liquid interface. The CA technique is deployed to track the new interface cells. The computer program was parallelized using the Message Passing Interface (MPI) technique. Parallel scaling of the algorithm was studied and major scalability bottlenecks were identified. Efficiency loss attributable to the high memory bandwidth requirement of the algorithm was observed when using multiple cores per processor. Parallel writing of the output variables of interest was implemented in the binary Hierarchical Data Format 5 (HDF5) to improve the output performance, and to simplify visualization. Calculations were carried out in single precision arithmetic without significant loss in accuracy, resulting in 50% reduction of memory and computational time requirements. The presented solidification model shows a very good scalability up to centimeter size domains, including more than ten million of dendrites. 相似文献
76.
The aim of this study was to fabricate antimicrobial calcium-alginate-based films containing the self-microemulsifying thyme essential oil (TEO) formulations using Tween 80 as the surfactant, and acetic (AA) or propionic (PA) acids as the cosurfactants. A Ca-alginate film containing nano-emulsified TEO as well as a neat Ca-alginate film were considered as the controls. The scanning electron microscopy micrographs showed a highly porous texture for SME films, which resulted in an increase in water vapor permeability and water absorption capacity of these films. The SME films released the TEO completely within 155 min and inhibited the growth of S. aureus and E. coli in in vitro antimicrobial tests. The population of S. aureus and E. coli reduced significantly in ground beef covered with SME films. The results of this study showed that self-microemulsifying TEO films could effectively increase the shelf life of ground beef by controlling its microbial population. 相似文献
77.
78.
79.
80.