全文获取类型
收费全文 | 2499篇 |
免费 | 90篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 31篇 |
化学工业 | 552篇 |
金属工艺 | 81篇 |
机械仪表 | 42篇 |
建筑科学 | 134篇 |
矿业工程 | 28篇 |
能源动力 | 54篇 |
轻工业 | 227篇 |
水利工程 | 16篇 |
石油天然气 | 13篇 |
无线电 | 148篇 |
一般工业技术 | 397篇 |
冶金工业 | 491篇 |
原子能技术 | 40篇 |
自动化技术 | 336篇 |
出版年
2022年 | 18篇 |
2021年 | 26篇 |
2020年 | 24篇 |
2019年 | 30篇 |
2018年 | 34篇 |
2017年 | 42篇 |
2016年 | 41篇 |
2015年 | 49篇 |
2014年 | 62篇 |
2013年 | 189篇 |
2012年 | 88篇 |
2011年 | 113篇 |
2010年 | 98篇 |
2009年 | 78篇 |
2008年 | 103篇 |
2007年 | 96篇 |
2006年 | 100篇 |
2005年 | 77篇 |
2004年 | 92篇 |
2003年 | 87篇 |
2002年 | 59篇 |
2001年 | 42篇 |
2000年 | 47篇 |
1999年 | 44篇 |
1998年 | 48篇 |
1997年 | 38篇 |
1996年 | 42篇 |
1995年 | 26篇 |
1994年 | 33篇 |
1993年 | 43篇 |
1992年 | 35篇 |
1991年 | 20篇 |
1990年 | 22篇 |
1989年 | 20篇 |
1988年 | 28篇 |
1987年 | 23篇 |
1986年 | 26篇 |
1985年 | 34篇 |
1984年 | 37篇 |
1983年 | 25篇 |
1982年 | 21篇 |
1981年 | 34篇 |
1980年 | 20篇 |
1979年 | 20篇 |
1978年 | 25篇 |
1977年 | 32篇 |
1976年 | 30篇 |
1975年 | 22篇 |
1974年 | 25篇 |
1972年 | 18篇 |
排序方式: 共有2590条查询结果,搜索用时 62 毫秒
1.
Alison Willette Benjamin Fallen Hem Bhandari Carl Sams Feng Chen Virginia Sykes Chris Smallwood Kristin Bilyeu Zenglu Li Vincent Pantalone 《Journal of the American Oil Chemists' Society》2021,98(8):861-869
Soybean oil hydrogenation alters the linolenic acid molecule to prevent the oil from becoming rancid, however, health reports have indicated trans-fat caused by hydrogenation, is not generally regarded as safe. Typical soybeans contain approximately 80 g kg−1 to 120 g kg−1 linolenic acid and 240 g kg−1 of oleic acid. In an effort to accommodate the need for high-quality oil, the United Soybean Board introduced an industry standard for a high oleic acid greater than 750 g kg−1 and linolenic acid less than 30 g kg−1 oil. By combing mutations in the soybean plant at four loci, FAD2-1A and FAD2-1B, oleate desaturase genes and FAD3A and FAD3C, linoleate desaturase genes, and seed oil will not require hydrogenation to prevent oxidation and produce high-quality oil. In 2017 and 2018, a study comparing four near-isogenic lines across multiple Tennessee locations was performed to identify agronomic traits associated with mutations in FAD3A and FAD3C loci, while holding FAD2-1A and FAD2-1B constant in the mutant (high oleic) state. Soybean lines were assessed for yield and oil quality based on mutations at FAD2-1 and FAD3 loci. Variations of wild-type and mutant genotypes were compared at FAD3A and FAD3C loci. Analysis using a generalized linear mixed model in SAS 9.4, indicated no yield drag or other negative agronomic traits associated with the high oleic and low linolenic acid genotype. All four mutations of fad2-1A, fad2-1B, fad3A, and fad3C were determined as necessary to produce a soybean with the new industry standard (>750 g kg−1 oleic and <30 g kg−1 linolenic acid) in a maturity group-IV-Late cultivar for Tennessee growers. 相似文献
2.
Effects of breed and age at slaughter on degradation of muscle lipids during processing of dry‐cured hams
下载免费PDF全文
![点击此处可从《International Journal of Food Science & Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Linda Storrustløkken Hanne Marie Devle Lars Erik Gangsei Carl Fredrik Naess‐Andresen Bjørg Egelandsdal Ole Alvseike Dag Ekeberg 《International Journal of Food Science & Technology》2015,50(8):1933-1943
Hams from Landrace, Duroc and Hampshire pigs slaughtered at ages 6, 7.5 and 9 months were processed to generate Norwegian Parma‐style hams. Lipid contents and the compositions of fatty acid classes (ΣSFA, ΣMUFA, ΣPUFA) within neutral lipids, phospholipids and free fatty acids were determined. Small differences in lipid degradation and composition of the classes were revealed. However, significant sensory differences related to lipids were observed. Breed was more important than age. Dry‐cured Hampshire hams gave a more intense mature odour that may be associated with higher overall lipid degradation. Unexpectedly, these hams also demonstrated high juiciness and tenderness, which could be related to the melting characteristics of the fat. Dry‐cured Duroc hams showed a higher susceptibility towards rancidity, presumably associated with preferential oxidation of n‐6 fatty acids relative to C18:1 n‐9. Dry‐cured Landrace hams showed the lowest juiciness and tenderness, likely due to their lower fat content (marbling). 相似文献
3.
The phospholipids of the spongePolymastia gleneni contain saturated long chain (C22–30)-acetoxy fatty acids. Their structures were assigned based on chromatographic and spectrometric data as well as comparison
with a synthetic sample. The use of capillary gas chromatography combined with chemical ionization and electron impact mass
spectrometry was instrumental in the eludication of structures, since only a very small amount of crude lipids was available.
Part 10 of “Phospholipids in Marine Organisms.” For Part 9 in this series, see reference 12. 相似文献
4.
This paper presents a methodology whereby the payload weight of a serial manipulator can be determined from a minimum set of sensor data, i.e., joint angle and joint torque measurements. The particular manipulator geometry that is analyzed is a four degree‐of‐freedom serial chain that is commonly used in excavator systems. It was quite remarkable that a relatively simple solution was obtained for the payload weight considering that there are a total of nine unknown moments and cross moments of inertia of the payload together with the unknown location of the center of mass. Example calculations are presented. © 2003 Wiley Periodicals, Inc. 相似文献
5.
Jānis Bārzdiņš Rūsiņš Freivalds Carl H. Smith 《Journal of Computer and System Sciences》2008,74(4):527-545
We study learning of predicate logics formulas from “elementary facts,” i.e. from the values of the predicates in the given model. Several models of learning are considered, but most of our attention is paid to learning with belief levels. We propose an axiom system which describes what we consider to be a human scientist's natural behavior when trying to explore these elementary facts. It is proved that no such system can be complete. However we believe that our axiom system is “practically” complete. Theorems presented in the paper in some sense confirm our hypothesis. 相似文献
6.
Awareness of the construction environment can be improved by automatic three-dimensional (3D) sensing and modeling of job sites in real time. Commercially available 3D modeling approaches based on range scanning techniques are capable of modeling static objects only, and thus cannot model dynamic objects in real time in an environment comprised of moving humans, equipment, and materials. Emerging prototype video range cameras offer an alternative by facilitating affordable, wide field of view, dynamic object tracking at frame rates better than 1?Hz (real time). This paper describes a methodology to model, detect, and track the position of static and moving objects in real time, based on data obtained from video range cameras. Experiments with this technology have produced results that indicate that video rate 3D data acquisition and analysis of construction environments can support effective modeling, detection, and tracking of project resources. This approach to job site awareness has inherent value and broad application. In combination with effective management practices and other sensing techniques, this technology has the potential to significantly improve safety on construction job sites. 相似文献
7.
Susskind Alex M.; Kacmar K. Michele; Borchgrevink Carl P. 《Canadian Metallurgical Quarterly》2003,88(1):179
The authors proposed and tested a model describing the relationship between customer service providers' perceptions and attitudes toward their service-related duties and their customers' perceptions of satisfaction with their service experiences. Results indicated that the perception of having standards for service delivery in an organization is strongly related to line-level employees' perceptions of support from coworkers and supervisors. Perceived support from coworker, was significantly related to service providers' customer orientation, whereas perceived support from supervisors showed a weaker relationship to a customer orientation. Ultimately, service providers' customer orientation was strongly related to customers' satisfaction with service. Finally, a set of post hoc analyses indicated that coworker and supervisory support explained a greater proportion of incremental variance in the model than did perceived organizational support alone. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
The performance of ARQ systems can be improved by combining current and prior transmissions at the receiver. Two techniques
for combining outputs in a packet-based communication system are presented. In both techniques the fundamental unit of retransmission
is a packet, and the fundamental unit of combining is a codeword. The techniques are analyzed for a bursty channel and a system
that employs Reed–Solomon coding and bounded-distance errors-and-erasures decoding. Performance results show that the packet-combining
schemes provide significant gains in throughput and reductions in error probability when compared with a system that does
not employ combining.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
9.
10.