全文获取类型
收费全文 | 478篇 |
免费 | 31篇 |
专业分类
电工技术 | 4篇 |
综合类 | 2篇 |
化学工业 | 168篇 |
金属工艺 | 2篇 |
机械仪表 | 11篇 |
建筑科学 | 12篇 |
矿业工程 | 2篇 |
能源动力 | 16篇 |
轻工业 | 41篇 |
水利工程 | 5篇 |
石油天然气 | 6篇 |
无线电 | 67篇 |
一般工业技术 | 80篇 |
冶金工业 | 40篇 |
原子能技术 | 3篇 |
自动化技术 | 50篇 |
出版年
2024年 | 3篇 |
2023年 | 13篇 |
2022年 | 25篇 |
2021年 | 30篇 |
2020年 | 20篇 |
2019年 | 31篇 |
2018年 | 39篇 |
2017年 | 24篇 |
2016年 | 24篇 |
2015年 | 14篇 |
2014年 | 24篇 |
2013年 | 31篇 |
2012年 | 22篇 |
2011年 | 45篇 |
2010年 | 20篇 |
2009年 | 21篇 |
2008年 | 11篇 |
2007年 | 10篇 |
2006年 | 12篇 |
2005年 | 7篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有509条查询结果,搜索用时 15 毫秒
51.
Mihailescu M Scarlat M Gheorghiu A Costescu J Kusko M Paun IA Scarlat E 《Applied optics》2011,50(20):3589-3597
This paper presents our method, which simultaneously combines automatic imaging, identification, and counting with the acquisition of morphological information for at least 1000 blood cells from several three-dimensional images of the same sample. We started with seeking parameters to differentiate between red blood cells that are similar but different with respect to their development stage, i.e., mature or immature. We highlight that these cells have different diffractive patterns with complementary central intensity distribution in a given plane along the propagation axis. We use the Fresnel approximation to simulate propagation through cells modeled as spheroid-shaped phase objects and to find the cell property that has the dominant influence on this behavior. Starting with images obtained in the reconstruction step of the digital holographic microscopy technique, we developed a code for automated simultaneous individual cell image separation, identification, and counting, even when the cells are partially overlapped on a slide, and accurate measuring of their morphological features. To find the centroids of each cell, we propose a method based on analytical functions applied at threshold intervals. Our procedure separates the mature from the immature red blood cells and from the white blood cells through a decision based on gradient and radius values. 相似文献
52.
Olimpia Daniela Frent Laura Gratiela Vicas Narcis Duteanu Claudia Mona Morgovan Tunde Jurca Annamaria Pallag Mariana Eugenia Muresan Sanda Monica Filip Roxana-Liana Lucaciu Eleonora Marian 《International journal of molecular sciences》2022,23(20)
From the multitude of materials currently available on the market that can be used in the development of microparticles, sodium alginate has become one of the most studied natural anionic polymers that can be included in controlled-release pharmaceutical systems alongside other polymers due to its low cost, low toxicity, biocompatibility, biodegradability and gelatinous die-forming capacity in the presence of Ca2+ ions. In this review, we have shown that through coacervation, the particulate systems for the dispensing of drugs consisting of natural polymers are nontoxic, allowing the repeated administration of medicinal substances and the protection of better the medicinal substances from degradation, which can increase the capture capacity of the drug and extend its release from the pharmaceutical form. 相似文献
53.
Children's perceived attachments with parents, and family cohesion and adaptability were examined as predictors, mediators, and moderators in the parental problem drinking-child outcomes link. A total of 216 6- to 12-year-olds (110 boys, 106 girls) participated. Data were obtained from children and their mothers, fathers, and teachers. A higher level of family cohesion and adaptability functioned as (a) a robust protective factor against adjustment and cognitive difficulties otherwise associated with problem drinking and (b) a mediator of adjustment problems. Children's perceptions of attachments to mothers and fathers were consistent predictors of behavioral, social, and cognitive problems and further moderated relations between problem drinking and child functioning. The results support that child-parent and family functioning variables act as either pathways and/or vulnerability and protective factors for children exposed to a high-risk environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
54.
Children's vagal tone was examined as a vulnerability factor in the longitudinal relation between mothers' (MPD) and fathers' (FPD) problem drinking and children's adjustment. At T1, MPD and FPD were examined, and children's vagal tone was assessed. Two years following initial participation, child adjustment problems were evaluated. A lower level of vagal tone was a vulnerability factor for internalizing problems associated with MPD and FPD and for externalizing difficulties associated with MPD. In the context of a higher level of MPD or FPD, a lower level of vagal tone was a vulnerability factor for increases in externalizing problems over time. Results are supportive of the importance of biopsychosocial perspectives in which child characteristics interact with family risk to predict psychopathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
55.
Mona Skaret Kjersti Bjrkeng Katja Maria Hydle 《Creativity & Innovation Management》2002,11(3):192-202
We argue that practical endeavours towards mobilising and recreating knowledge is an integral part of value increasing activities, and expose how this dependency can be utilised in ameliorating practice. This bridging of knowledge and value creation constitutes organisational activities as knowing. The paper exposes the efforts of Telenor, a large telecom firm, to create an enduring agenda for non‐financial issues in management. We expose the development process and initial use of their new Integrated Management Business Model. This involves identifying financial and non‐financial drivers of future performance within and across several business units, as well as negotiating on appropriate indicators of both status and change. The paper pays special attention to the iterative approach to development in order to highlight a shift from an attempt to enable knowledge in autonomous processes secluded from everyday activities, towards an understanding of knowledge and knowing as intrinsic to the value creating activities performed. By entering the issue of intangibles through the knowing activity perspective, it was evident that the purpose of the management system was not to determine the status of intangibles in the corporation, it was to improve it. 相似文献
56.
Mona E. McAlarney Richard M. Arons Tim E. Howson John K. Tien Sanford Baranow 《Metallurgical and Materials Transactions A》1982,13(8):1453-1462
The creep and stress rupture properties of an oxide (Y2O3) dispersion strengthened nickel-base alloy, which also is strengthened by γ′ precipitates, was studied at 760 °C and 1093
°C. At both temperatures the alloy YDNiCrAl exhibits unusually high stress rupture ductility as measured by both elongation
and reduction in area. Failure was transgranular, and different modes of failure were observed including crystallographic
fracture at intermediate temperatures and tearing or necking almost to a chisel point at higher temperatures. While the rupture
ductility was high, the creep strength of the alloy was low relative to conventional γ′ strengthened superalloys in the intermediate
temperature range and to ODS alloys in the higher temperature range. These findings are discussed with respect to the alloy
composition; the strengthening oxide phases, which are inhomogeneously dispersed; the grain morphology, which is coarse and
elongated and exhibits many included grains; and the second phase inclusion particles occurring at grain boundaries and in
the matrix. The creep properties, in particular the high stress dependencies and high creep activation energies measured,
are discussed with respect to the resisting stress model of creep in particle strengthened alloys.
RICHARD M. ARONS, formerly a Graduate Student at Columbia University 相似文献
57.
58.
Mona Ahmed J. Alzahrani Conrad O. Perera Yacine Hemar 《International Journal of Food Science & Technology》2018,53(3):676-682
This research focuses on green production of bioactive proteins and hydrolysates from Nitzschia. A comparison of antioxidant activities was established between protein extracts and hydrolysates from Nitzschia and two other well‐known microalgae, chlorella and spirulina. Protein hydrolysates from these microalgae were produced using Alcalase®, Flavourzyme® and Trypsin. The hydrolysis process enhanced the antioxidant activities in general, especially those obtained using Alcalase®. Nitzschia showed the highest (P < 0.05) total phenolic content/reducing capacity (2.4 ± 0.02 mg GAE/100 g) after 90 min of hydrolysis with Alcalase®. The ABTS [2,2′‐Azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid)] radical scavenging activity (66.77 ± 0.00%) was highest (P < 0.05) after 120 min of hydrolysis, but DPPH (2,2‐Diphenyl‐1‐picrylhydrazyl radical) was low (29.59 ± 0.02%). A correlation between ABTS activity and total phenolic contents was the highest (P < 0.05) for protein hydrolysates from all three organisms using Alcalase®, but superoxide anion radical scavenging activity was intermediate for Nitzschia. Therefore, Nitzschia protein hydrolysates have the potential to be used as antioxidants. 相似文献
59.
In this study pinch technology has been improved for wastewater temperature reduction. Having considered design grouping rules on the basis of pinch technology, a new debottlenecking procedure for thermal treatment of the wastewater network, has been introduced. In the presented procedure, better thermal treatment of effluent network using the new method can be used to avoid investment in new cooling tower capacity and to improve the performance of the tower in a systematic way. Related coding in Visual Sudio.Net 2003, C++, has been developed for the illustrative example to get optimal values in the cooling water design method computations. 相似文献
60.