全文获取类型
收费全文 | 2432篇 |
免费 | 103篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 16篇 |
综合类 | 2篇 |
化学工业 | 440篇 |
金属工艺 | 17篇 |
机械仪表 | 22篇 |
建筑科学 | 101篇 |
矿业工程 | 2篇 |
能源动力 | 32篇 |
轻工业 | 371篇 |
水利工程 | 23篇 |
石油天然气 | 9篇 |
武器工业 | 1篇 |
无线电 | 153篇 |
一般工业技术 | 375篇 |
冶金工业 | 722篇 |
原子能技术 | 1篇 |
自动化技术 | 253篇 |
出版年
2023年 | 25篇 |
2022年 | 52篇 |
2021年 | 81篇 |
2020年 | 48篇 |
2019年 | 51篇 |
2018年 | 53篇 |
2017年 | 48篇 |
2016年 | 45篇 |
2015年 | 60篇 |
2014年 | 69篇 |
2013年 | 101篇 |
2012年 | 93篇 |
2011年 | 141篇 |
2010年 | 95篇 |
2009年 | 102篇 |
2008年 | 130篇 |
2007年 | 136篇 |
2006年 | 109篇 |
2005年 | 103篇 |
2004年 | 104篇 |
2003年 | 81篇 |
2002年 | 66篇 |
2001年 | 36篇 |
2000年 | 37篇 |
1999年 | 47篇 |
1998年 | 80篇 |
1997年 | 55篇 |
1996年 | 64篇 |
1995年 | 38篇 |
1994年 | 29篇 |
1993年 | 34篇 |
1992年 | 17篇 |
1991年 | 20篇 |
1990年 | 27篇 |
1989年 | 19篇 |
1988年 | 17篇 |
1987年 | 20篇 |
1986年 | 16篇 |
1985年 | 21篇 |
1984年 | 16篇 |
1983年 | 13篇 |
1982年 | 16篇 |
1981年 | 21篇 |
1980年 | 8篇 |
1979年 | 13篇 |
1978年 | 11篇 |
1977年 | 13篇 |
1976年 | 20篇 |
1975年 | 9篇 |
1973年 | 11篇 |
排序方式: 共有2540条查询结果,搜索用时 0 毫秒
61.
Wansang Lim Rebecca Miller Jungeun Park Sunghun Park 《Journal of food science》2014,79(6):S1212-S1217
Tomatoes have ameliorative effects on cardiovascular disease and cancer. In this study, metabolic engineering of flavonoids was utilized to improve the nutritional value of tomatoes by increasing flavonol and anthocyanin content. Total flavonol content was significantly increased in both the peel and flesh using the onion chalcone isomerase (CHI) gene. The Delila (Del) and Rosea1 (Ros1) genes from the snapdragon Antirrhinum majus were concomitantly expressed to produce an anthocyanin‐rich tomato which was purple in color. Sensory evaluation by a panel of 81 untrained consumers revealed no significant difference in liking of color or texture between CHI, Del/Ros1, and wild‐type tomatoes. Consumers reported marginal but significantly higher preference for the flavor and overall liking of CHI tomatoes over Del/Ros1 and wild‐type tomatoes. This study is the first to report the results of sensory tests of transgenic tomatoes by a consumer panel representing the general consuming public. 相似文献
62.
Spray drying of a phenolic‐rich membrane filtration fraction of olive mill wastewater: optimisation and dried product quality 下载免费PDF全文
Ivana Sedej Rebecca Milczarek Selina C. Wang Runqi Sheng Roberto de Jesús Avena‐Bustillos Lan Dao Gary Takeoka 《International Journal of Food Science & Technology》2016,51(8):1900-1909
Olive mill wastewater (OMWW) from 3‐ and 2‐phase mills was subjected to a two‐step membrane filtration process. The obtained reverse osmosis retentate (RO‐R) is a phenolic‐rich coproduct stream, and the reverse osmosis permeate is a near‐pure water stream. A pilot‐scale spray dryer was used for the production of RO‐R powder. The optimum temperature/feed pump conditions were obtained for 3‐phase (150°C/4.4 Hz) and for 2‐phase RO‐R (175°C/3.8 Hz). The powders obtained by spray drying under these conditions were analysed for physicochemical properties, including identification and quantification of phenolic compounds. Protocatechuic acid, 3‐hydroxytyrosol, tyrosol, vanillic acid and p‐coumaric acid were quantified in both RO‐R powders, which show the possibility to obtain a phenolic‐rich powder from an OMWW filtration fraction. This will lead towards better usage of by‐products from olive oil production. 相似文献
63.
Alexander V. Zavgorodniy Rebecca S. Mason Racquel Z. LeGeros Ramin Rohanizadeh 《Surface & coatings technology》2012
Monetite is a promising biomaterial for restoring the function of the compromised skeletal structures due to its superior osteoconductive and resorption properties. However, its potential as a coating for orthopaedic implants in load bearing applications has not yet been investigated. The aim of this study was to prepare monetite coating on Ti substrate in mild conditions, which may allow incorporation of protein-based drugs during the coating deposition. Coatings were prepared using chemical deposition of monetite on Ti substrate in acidic conditions at 75 °C for 24 h. Coatings were characterised by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Adhesion of the coatings to Ti substrate was measured using tensile tests. EDS confirmed the calcium phosphate nature of the coating and XRD and FTIR confirmed the monetite phase of the coatings. SEM revealed that the coatings were formed of densely packed plate-like monetite crystals, with the crystal size approximately 20 × 10 × 5 μm. Adhesion tests showed cohesive failure of the monetite coatings and the tensile strength of the coating was in the range of 15.43 ± 0.20 MPa. Mechanical tests showed that monetite coatings were stable and could be considered for use with Ti orthopaedic implants. 相似文献
64.
Ben Kent Taavi Hunt Tamim A. Darwish Thomas Hau? Christopher J. Garvey Gary Bryant 《Journal of the Royal Society Interface》2014,11(95)
Trehalose, a natural disaccharide with bioprotective properties, is widely recognized for its ability to preserve biological membranes during freezing and dehydration events. Despite debate over the molecular mechanisms by which this is achieved, and that different mechanisms imply quite different distributions of trehalose molecules with respect to the bilayer, there are no direct experimental data describing the location of trehalose within lipid bilayer membrane systems during dehydration. Here, we use neutron membrane diffraction to conclusively show that the trehalose distribution in a dioleoylphosphatidylcholine (DOPC) system follows a Gaussian profile centred in the water layer between bilayers. The absence of any preference for localizing near the lipid headgroups of the bilayers indicates that the bioprotective effects of trehalose at physiologically relevant concentrations are the result of non-specific mechanisms that do not rely on direct interactions with the lipid headgroups. 相似文献
65.
66.
Rebecca Shawcross 《Costume》2013,47(1):130-132
AbstractThis paper examines the influence that the costume designers of the Ballets Russes, many of whom were important artists from significant art movements of the day, had on contemporaneous fashion. It looks at why in particular the 'Ballets Russes' artists Leon Bakst and Natalia Goncharova went on to involve themselves in actual fashion production and the similarities between their work and the fashion designers producing work at the same time, principally Paul Poiret, Mariano Fortuny and Coco Chanel. Overall, this paper investigates the significance of the cultural times and of the distinct characteristics of the separate art forms, that may have encouraged avant-garde art and fashion to crossover and collaborate so unreservedly. 相似文献
67.
Per Kreuger Rebecca Steinert Olof Görnerup Daniel Gillblad 《International Journal of Network Management》2018,28(2)
Managing and balancing load in distributed systems remains a challenging problem in resource management, especially in networked systems where scalability concerns favour distributed and dynamic approaches. Distributed methods can also integrate well with centralised control paradigms if they provide high‐level usage statistics and control interfaces for supporting and deploying centralised policy decisions. We present a general method to compute target values for an arbitrary metric on the local system state and show that autonomous rebalancing actions based on the target values can be used to reliably and robustly improve the balance for metrics based on probabilistic risk estimates. To balance the trade‐off between balancing efficiency and cost, we introduce 2 methods of deriving rebalancing actuations from the computed targets that depend on parameters that directly affects the trade‐off. This enables policy level control of the distributed mechanism based on collected metric statistics from network elements. Evaluation results based on cellular radio access network simulations indicate that load balancing based on probabilistic overload risk metrics provides more robust balancing solutions with fewer handovers compared to a baseline setting based on average load. 相似文献
68.
69.
Rebecca Lace Celia Murray-Dunning Rachel Williams 《Journal of Materials Science》2015,50(4):1523-1534
Synthetic materials have played a significant role in ophthalmic applications to improve vision for many years. This has been in four main areas in ophthalmology: ocular surface reconstruction, lens replacement, vitreous replacement and structural support and cell transplantation in the retina. Corneal replacement therapies have been developed using both synthetic acrylic-based materials and more recently naturally derived materials such as amniotic membrane. Intraocular lenses as a replacement for the natural lens post cataract surgery has been used for many years. Newer developments include the opportunity to use gels so that the lenses can accommodate but these need improving in terms of the cross-linking chemistry. Silicone oils have been used as long-term tamponade agents as vitreous replacements but recent developments in their properties has enhanced the clinical outcomes and further research into their use as drug delivery vehicles will be a major advancement. Regenerative medicine therapies to repopulate the retina to repair and replace specific cell layers require the optimisation of synthetic scaffolds and this is a major area for development. Recent developments in biomaterials have emphasised the importance of the physical, chemical and mechanical properties specific to a particular ophthalmic application. Materials science has a critical role in developing strategies to overcome vision loss. 相似文献
70.