全文获取类型
收费全文 | 2034篇 |
免费 | 158篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 36篇 |
综合类 | 3篇 |
化学工业 | 453篇 |
金属工艺 | 33篇 |
机械仪表 | 29篇 |
建筑科学 | 68篇 |
矿业工程 | 5篇 |
能源动力 | 46篇 |
轻工业 | 131篇 |
水利工程 | 7篇 |
石油天然气 | 3篇 |
无线电 | 219篇 |
一般工业技术 | 370篇 |
冶金工业 | 448篇 |
原子能技术 | 11篇 |
自动化技术 | 331篇 |
出版年
2023年 | 36篇 |
2022年 | 69篇 |
2021年 | 80篇 |
2020年 | 56篇 |
2019年 | 73篇 |
2018年 | 81篇 |
2017年 | 78篇 |
2016年 | 84篇 |
2015年 | 57篇 |
2014年 | 82篇 |
2013年 | 94篇 |
2012年 | 76篇 |
2011年 | 124篇 |
2010年 | 59篇 |
2009年 | 62篇 |
2008年 | 68篇 |
2007年 | 71篇 |
2006年 | 65篇 |
2005年 | 40篇 |
2004年 | 36篇 |
2003年 | 34篇 |
2002年 | 36篇 |
2001年 | 42篇 |
2000年 | 21篇 |
1999年 | 35篇 |
1998年 | 140篇 |
1997年 | 62篇 |
1996年 | 52篇 |
1995年 | 41篇 |
1994年 | 24篇 |
1993年 | 18篇 |
1992年 | 13篇 |
1991年 | 9篇 |
1990年 | 14篇 |
1989年 | 15篇 |
1988年 | 19篇 |
1987年 | 28篇 |
1986年 | 16篇 |
1985年 | 13篇 |
1984年 | 10篇 |
1983年 | 10篇 |
1982年 | 13篇 |
1981年 | 6篇 |
1980年 | 11篇 |
1978年 | 7篇 |
1977年 | 13篇 |
1976年 | 24篇 |
1975年 | 7篇 |
1973年 | 8篇 |
1971年 | 8篇 |
排序方式: 共有2193条查询结果,搜索用时 15 毫秒
81.
82.
83.
Hans-Ulrich Waiblinger Miriam Schillinger Norbert Hess 《Journal für Verbraucherschutz und Lebensmittelsicherheit》2012,7(2):163-170
Here, we describe the procedure of a DNA extraction method from maize starch including the method??s validation by in-house and interlaboratory tests. The amplifiable amount of maize DNA tested by real-time PCR was used as parameter for evaluating our method. The practical (i.e. relative) limit of detection (LOD) was used as key criterion for assessing the suitability of the extraction method with respect to genetically modified organism analysis. In a round-robin test with ten participating laboratories, satisfactory results were achieved with practical LODs in the range of 0.1?% with three native maize starch materials. In-house tests showed that this protocol??with an additional purification step??can also be applied for extracting DNA from chemically or enzymatically modified starch. 相似文献
84.
85.
L. Antonio González-Grajales Laura Pieper Stefan Görner Philipp Görner Rudolf Staufenbiel 《Journal of dairy science》2019,102(4):3609-3614
Few studies have compared individual variability of an intravenous glucose tolerance test (ivGTT) obtained daily in young cattle. The objective of this study was to evaluate the repeatability of glucose traits and insulin responses derived from ivGTT during 3 consecutive days in Holstein-Friesian cattle (bulls: n = 4, steers: n = 3, heifers: n = 3). Blood collections were performed from min 0 (basal concentrations) to min 63 (last measurement). Additional estimates included maximal concentration for glucose and insulin, glucose half-life time (GHLT), and glucose and insulin area under the curve. Glucose traits showed higher repeatability when compared with insulin responses. On average, the glucose trait and insulin response with the lowest coefficient of variation was GHLT (0.7%) and insulin area under the curve (21.3%), respectively. In addition, a general linear model with repeated measures was used to test for significant differences in glucose and insulin concentrations over time at different trial days. Both glucose and insulin concentrations were influenced by time point but not by trial day or time point × trial day. The results from this study showed that individual insulin responses were more variable than glucose traits. The high repeatability of GHLT evidenced the strict regulatory glucose disposal mechanisms occurring in young Holstein-Friesian cattle, whereas insulin responses showed high variability despite controlled management and nutritional practices. 相似文献
86.
Norgauer Philipp Grunewald Laura Priester Lena Heilemann Jens Hein Michael Stahl Karsten 《Forschung im Ingenieurwesen》2020,84(2):141-150
Forschung im Ingenieurwesen - Schneckengetriebe finden sich in verschiedenen Anwendungen als Stell- und Leistungsgetriebe. Aufgrund der Realisierbarkeit einer hohen Übersetzung bei kleinem... 相似文献
87.
Moritz Riebisch Philipp Weiß Clemens Cremer Ibrahim Aboulkhair Andreas Bührig-Polaczek 《Materials Science & Technology》2018,34(6):725-730
Solid solution-strengthened ductile iron (DI) exhibits outstanding mechanical properties due to the high silicon content. The strengthening by silicon addition is limited since additions above 4.3?wt-% lead to embrittlement. For a further improvement of mechanical properties, other alloying elements need to be considered. In the present work, the effect of various copper additions on the microstructure and the mechanical properties of solid solution-strengthened DI were investigated. The results show that no appreciable strengthening can be achieved by copper addition without the formation of pearlite in the matrix. The pearlite content increases considerably for Cu-additions above 0.23?wt-% and is independent of the cooling rate for the cooling conditions analysed. 相似文献
88.
89.
90.
Software and Systems Modeling - Automotive software architectures describe distributed functionality by an interaction of software components. One drawback of today’s architectures is their... 相似文献