全文获取类型
收费全文 | 1977篇 |
免费 | 61篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 58篇 |
综合类 | 9篇 |
化学工业 | 527篇 |
金属工艺 | 37篇 |
机械仪表 | 64篇 |
建筑科学 | 52篇 |
矿业工程 | 7篇 |
能源动力 | 50篇 |
轻工业 | 227篇 |
水利工程 | 19篇 |
石油天然气 | 4篇 |
无线电 | 133篇 |
一般工业技术 | 300篇 |
冶金工业 | 213篇 |
原子能技术 | 23篇 |
自动化技术 | 321篇 |
出版年
2022年 | 13篇 |
2021年 | 38篇 |
2020年 | 22篇 |
2019年 | 24篇 |
2018年 | 24篇 |
2017年 | 37篇 |
2016年 | 61篇 |
2015年 | 39篇 |
2014年 | 54篇 |
2013年 | 98篇 |
2012年 | 87篇 |
2011年 | 98篇 |
2010年 | 75篇 |
2009年 | 96篇 |
2008年 | 84篇 |
2007年 | 80篇 |
2006年 | 61篇 |
2005年 | 61篇 |
2004年 | 55篇 |
2003年 | 50篇 |
2002年 | 57篇 |
2001年 | 41篇 |
2000年 | 34篇 |
1999年 | 31篇 |
1998年 | 43篇 |
1997年 | 35篇 |
1996年 | 29篇 |
1995年 | 28篇 |
1994年 | 28篇 |
1993年 | 31篇 |
1992年 | 27篇 |
1991年 | 18篇 |
1990年 | 17篇 |
1989年 | 20篇 |
1988年 | 13篇 |
1987年 | 18篇 |
1986年 | 13篇 |
1985年 | 22篇 |
1984年 | 20篇 |
1983年 | 26篇 |
1982年 | 13篇 |
1981年 | 18篇 |
1980年 | 19篇 |
1979年 | 29篇 |
1978年 | 21篇 |
1977年 | 22篇 |
1975年 | 16篇 |
1974年 | 24篇 |
1973年 | 12篇 |
1971年 | 11篇 |
排序方式: 共有2044条查询结果,搜索用时 0 毫秒
91.
Towards cognitive evaluation of computer-drawn sketches 总被引:1,自引:0,他引:1
This paper seeks to raise visual comparisons beyond subjective opinions into evidence-based visual reasoning. It provides
an informal deductive analysis of the marks in sketches derived with two competing line-filtering algorithms. This prompted
the novel speculation that the visual system might be placing some types of anomalies in the foreground of mental 3D space,
where they can be ignored. A brief survey is provided to encourage informed debate. Although the proposed cognitive computation
was not automated, it justified the rejection of the Douglas–Peucker algorithm in favour of Visvalingam's algorithm in subsequent
research within the Cartographic Information Systems Research Group (CISRG). 相似文献
92.
Kurt P. Judmann 《e & i Elektrotechnik und Informationstechnik》2002,119(11):a16-a16
Sciencenews10-Jahr-Feier
Institut für Maschinelles Sehen und Darstellen 相似文献93.
Leith EN Mills KD Grannell S Dilworth DS Athey BD Lopez J 《Journal of the Optical Society of America. A, Optics, image science, and vision》2002,19(3):532-536
The method of Fourier optics is applied to the problem of time-gated imaging through scattering media. Tb adapt the problem to this treatment, appropriate alterations are made: The continuous medium is replaced by a cascade of thin scatterers, and a spatial filtering process is substituted for the conventional gating processes. Closed-form solutions are derived. 相似文献
94.
Keisuke Omae In-Tae Bae Muneyuki Naito Manabu Ishimaru Yoshihiko Hirotsu James A. Valdez Kurt E. Sickafus 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2006,250(1-2):300-302
We have performed high-dose Fe ion implantation into Si and characterized ion-beam-induced microstructures as well as annealing-induced ones using transmission electron microscopy (TEM) and grazing-incidence X-ray diffraction (GIXRD). Single crystals of Si(1 0 0) substrate were irradiated at 623 K with 120 keV Fe+ ions to a fluence of 4 × 1017 cm−2. The irradiated samples were then annealed in a vacuum furnace at temperatures ranging from 773 K to 1073 K. Cross-sectional TEM observations and GIXRD measurements revealed that a layered structure is formed in the as-implanted specimen with ε-FeSi, β-FeSi2 and damaged Si, as component layers. A continuous β-FeSi2 layer was formed on the topmost layer of the Si substrate after thermal annealing. 相似文献
95.
Kurt Beyer 《AI & Society》2002,16(3):278-287
This narrative describes the making of a German electrical engineer, Kurt Beyer, into a micro-entrepreneur. He set for himself
the goal of sailing around the world in his own vessel – without being able to afford to buy such a ship. Many people in Germany
have in recent years started to build their own sea-going vessels in order to escape from the creativity-stifling and restrictive
patterns of their lives and work. Only a few of them have ever finished building their vessels. Firstly, this report describes
the experiences of one of those few who have made it. Secondly, it tells the story of how this engineer himself turned into
a micro-entrepreneur during the period of yacht-building and how later he started his own charter enterprise, centred around
his yacht. Following the model of entrepreneurship described by Dassen-Housen in this issue of AI & Society, the narrative illustrates what it means to run such an enterprise in view of the international competition. Here follows
the narrative of the engineer and ship-builder himself (translated by D. Brandt). 相似文献
96.
The objective of this study is to investigate experimentally and theoretically whether sodium carbonate (Na2CO3) salt is suitable for establishing a salinity gradient in a salt-gradient solar-pond (SGSP). For this purpose, a small-scale prismatic solar-pond was constructed. Experiments were conducted in the laboratory under the incident radiation from two halogen-lamps acting as a solar simulator. Furthermore, a one-dimensional transient mathematical model that describes the heat and mass transfer behaviour of the SGSP was developed. The differential equations obtained were solved numerically using a finite-difference method. It was found from the experiments that the density gradient, achieved using sodium carbonate salt, can suppress convection from the bottom to the surface of the pond. 相似文献
97.
Pipp Sandra; Shaver Phillip; Jennings Sybillyn; Lamborn Susie; Fischer Kurt W. 《Canadian Metallurgical Quarterly》1985,48(4):991
Assessed 100 undergraduates' developmental theories about their affective relationships with their parents, using a retrospective method. Ss used drawings and questionnaire ratings to portray their relationships with parents at 5 points between infancy and the present. From infancy to their current age, Ss portrayed their relationships in 2 major ways: They perceived themselves as gaining in responsibility, dominance, independence, and similarity from infancy to the present, whereas they portrayed their parents as experiencing a decline on these dimensions. For variables indicating closeness and love, however, there was a striking discontinuity in these linear trends: Although Ss perceived linear trends from infancy to adolescence, they depicted their current relationships as involving a great deal more love and closeness. They also portrayed their relationships with mothers and fathers somewhat differently. More responsibility was felt toward the mothers and they were portrayed as especially friendly, but Ss felt more similar to their fathers, whom they perceived as dominant. Results suggest that late adolescents construct theories of the affective components of their relationships with their parents to serve the needs of separation while maintaining a close affective tie to the parents. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
98.
Kurt Heyns und Helmut Koch 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1971,145(2):76-84
Zusammeufassung Zur Überprüfung des Auftretens von Nitrosaminen [2] im Rahmen der Maillard-Reaktion wurden die flüchtigen Produkte verschiedener Glucose-Aminosäure-Modell-gemische durch Kombination von Gaschromatographie and Massenspektrometrie, Polarographie und Dünnschicht-Chromatographie untersucht. Das Auftreten von Nitrosaminen kann durch die Ergebnisse eindeutig ausgeschlossen werden.
The problem of formation of nitrosamines by reacting monosaccharides with aminoacids (maillard-reaction)
Summary For proving the formation of nitrosamines applying maillardconditions [2] we tested the volatile reaction products of various glucose-aminoacid mixtures by coupling gas chromatography and mass spectrometry, polarography and thin-layer chromatography. The appearence of nitrosamines could undoubtedly be excluded according to the results.相似文献
99.
100.
Kurt R Bogner HR Straton JB Tien AY Gallo JJ 《Computer methods and programs in biomedicine》2004,73(2):165-171
We wanted to test the psychometric reliability and validity of self-reported information on psychological and functional status gathered by computer in a sample of primary care outpatients. Persons aged 65 years and older visiting a primary care medical practice in Baltimore (n=240) were approached. Complete baseline data were obtained for 54 patients and 34 patients completed 1-week retest follow-up. Standard instruments were administered by computer and also given as paper and pencil tests. Test-retest reliability estimates were calculated and comparisons across mode of administration were made. Separately, an interviewer administered a questionnaire to gauge patient attitudes and feelings after using the computer. Most participants (72%) reported no previous computer use. Nevertheless, inter-method reliability of the GDS15 at baseline (0.719, n=47), intra-method reliability of the computer in time (0.797, n=31), inter-method reliability of the CESDR20 at baseline (0.740, n=53), and the correlation between the CESDR20 computer version at baseline and follow-up (0.849, n=34) were all excellent. The inter-method reliability of the CESDR20 at follow-up (0.615, n=37) was lower but still acceptable. Although 28% were anxious prior to using the computer testing system, that percent decreased to 19% while using the system. The efficiency and reliability in comparison to the paper instruments were good or better. Even though most participants had not ever used a computer prior to participating in the study, they had generally favorable attitudes toward the use of computers, and also reported having favorable experience with the computer testing system. 相似文献