全文获取类型
收费全文 | 614篇 |
免费 | 23篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 116篇 |
金属工艺 | 6篇 |
机械仪表 | 10篇 |
建筑科学 | 18篇 |
能源动力 | 17篇 |
轻工业 | 72篇 |
水利工程 | 3篇 |
无线电 | 26篇 |
一般工业技术 | 108篇 |
冶金工业 | 161篇 |
原子能技术 | 4篇 |
自动化技术 | 89篇 |
出版年
2023年 | 3篇 |
2022年 | 12篇 |
2021年 | 17篇 |
2020年 | 7篇 |
2019年 | 13篇 |
2018年 | 10篇 |
2017年 | 11篇 |
2016年 | 13篇 |
2015年 | 14篇 |
2014年 | 9篇 |
2013年 | 40篇 |
2012年 | 32篇 |
2011年 | 41篇 |
2010年 | 28篇 |
2009年 | 17篇 |
2008年 | 25篇 |
2007年 | 18篇 |
2006年 | 11篇 |
2005年 | 12篇 |
2004年 | 12篇 |
2003年 | 15篇 |
2002年 | 15篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 13篇 |
1998年 | 50篇 |
1997年 | 33篇 |
1996年 | 21篇 |
1995年 | 19篇 |
1994年 | 15篇 |
1993年 | 11篇 |
1992年 | 4篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 8篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 12篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1971年 | 2篇 |
1962年 | 2篇 |
排序方式: 共有637条查询结果,搜索用时 15 毫秒
631.
A.O. Lobo E.F. Antunes M.B.S. Palma C. Pacheco-Soares V.J. Trava-Airoldi E.J. Corat 《Materials science & engineering. C, Materials for biological applications》2008,28(4):532-538
Cell adhesion and cell viability of aligned multi-walled carbon nanotube (MWCNT) films were verified using Fibroblast L929 mouse cells. The MWCNTs were produced by a microwave plasma chemical vapor deposition (2.45 GHz) on silicon (Si), with a nickel catalyst, and titanium (Ti), with an iron catalyst. MTT assay and cellular adhesion were used for biocompatibility tests (ISO 10993-5). The results show very high cell viability and many layers of cells adhered on the surface formed by the nanotube tips at films grown on silicon surfaces. The MWCNT grown on Ti surfaces presented lower cell viability and a reduced number of cells on the surface formed by the nanotube tips. The different behavior is most probably related to excess iron contamination present in the case of titanium substrate, while nickel catalyst is probably enclosed by the nanotubes. 相似文献
632.
633.
Lobo JR Moradi M Chng N Dehghan E Morris WJ Fichtinger G Salcudean SE 《IEEE transactions on medical imaging》2012,31(3):738-748
We aim to compute the movement of permanent stranded implant brachytherapy radioactive sources (seeds) in the prostate from the planned seed distribution to the intraoperative fluoroscopic distribution, and then to the postimplant computed tomography (CT) distribution. We present a novel approach to matching the seeds in these distributions to the plan by grouping the seeds into needle tracks. First, we identify the implantation axis using a sample consensus algorithm. Then, we use a network flow algorithm to group seeds into their needle tracks. Finally, we match the needles from the three stages using both their transverse plane location and the number of seeds per needle. We validated our approach on eight clinical prostate brachytherapy cases, having a total of 871 brachytherapy seeds distributed in 193 needles. For the intraoperative and postimplant data, 99.31% and 99.41% of the seeds were correctly assigned, respectively. For both the preplan to fluoroscopic and fluoroscopic to CT registrations, 100% of the needles were correctly matched. We show that there is an average intraoperative seed displacement of 4.94±2.42 mm and a further 2.97±1.81 mm of postimplant movement. This information reveals several directional trends and can be used for quality control, treatment planning, and intraoperative dosimetry that fuses ultrasound and fluoroscopy. 相似文献
634.
Carlos Eduardo Lobo e Silva Geoffrey J. D. Hewings 《The Annals of Regional Science》2012,48(3):703-717
The main purpose of the paper is to provide a link between the location decision and the internal organization of vertically integrated firms. The results of the model show that the decisions about location and managerial (de)centralization are interdependent: For certain parameters, firms should change both aspects simultaneously as a response to lower communication costs. The positive correlation between the decentralization of decision-making and geographic decentralization predicted by the model is supported by empirical research. 相似文献
635.
Roberto E. Armenta Mercia C. Valentine 《Journal of the American Oil Chemists' Society》2013,90(2):167-182
Omega-3 fatty acids, namely docosahexaenoic acid and eicosapentaenoic acid, have been linked to several beneficial health effects (i.e. mitigation effects of hypertension, stroke, diabetes, osteoporosis, depression, schizophrenia, asthma, macular degeneration, rheumatoid arthritis, etc.). The main source of omega-3 fatty acids is fish oil; lately however, fish oil market prices have increased significantly. This has prompted a significant amount of research on the use of single-cell oils as a source of omega-3 fatty acids. Some of the microbes reported to produce edible oil that contains omega-3 fatty acids are from the genus Schizochytrium, Thraustochytrium and Ulkenia. An advantage of a single cell oil is that it usually contains a significant amount of natural antioxidants (i.e. carotenoids and tocopherols), which can protect omega-3 fatty acids from oxidation, hence making this oil less prone to oxidation than oils derived from plants and marine animals. Production yields of single cell oils and of omega-3 fatty acids vary with the microbe used, with the fermentative growing conditions, and extractive procedures employed to recover the oil. This paper presents an overview of recent advances, reported within the last 10 years, in the production of single cell oils rich in omega-3 fatty acids. 相似文献
636.
G. E. Haniotakis V. G. Mavraganis Valentine Ragoussis 《Journal of chemical ecology》1989,15(3):1057-1065
l,5,7-Trioxaspiro[5.5]undecane, an analog of the major sex pheromone (olean) of the olive fruit fly, was synthesized via two different routes and tested for biological activity under laboratory and field conditions. In laboratory tests, its activity was comparable to that of olean, especially when a stabilizer or a high concentration was used. In field tests, its activity reached the level of olean only when a stabilizer and an open-type dispenser, which allows high rates of evaporation, were used. The residual activity of the analog dispensers did not exceed two weeks both under laboratory and field conditions compared to over four months for olean. 相似文献
637.
M. Gloria Lobo M. P. Cano 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1998,206(5):343-349
The physical, physico-chemical and sensorial changes that occur during the freezing and frozen storage of hermaphrodite and
female papaya slices (Carica papaya L., cv Sunrise, Solo group) were studied. Samples were evaluated by panellists throughout a 1-year period of storage at –24°C;
the panellists described the fruit in terms of physico-chemical measurements of texture (firnmess and total pectins content),
colour [L, a
L
, b
L
, peroxidase (POD) and polyphenoloxidase (PPO) activities] and flavour/taste [soluble solids content, pH, tritatable acidity
and quality index (oBrix/acidity)], and ranked them in order of preference. Desserts prepared from frozen slices of hermaphrodite and female papaya
fruits mixed with orange, lemon and sugar were also evaluated. The freezing process itself did not result in significant changes
in the more commonly assessed quality parameters of texture, colour and flavour/taste. However, during storage at –24°C, changes
in sensorial characteristics occurred that became more evident as storage continued (≤ 9 months). Nevertheless, these quality
changes can be masked by using these papaya slices as an ingredient in fruit products, with frozen female papaya slices being
especially suitable for this purpose.
Received: 1 August 1997 / Revised version: 14 November 1997 相似文献