全文获取类型
收费全文 | 591篇 |
免费 | 35篇 |
专业分类
化学工业 | 143篇 |
金属工艺 | 6篇 |
机械仪表 | 5篇 |
建筑科学 | 25篇 |
矿业工程 | 2篇 |
能源动力 | 11篇 |
轻工业 | 228篇 |
水利工程 | 5篇 |
石油天然气 | 3篇 |
无线电 | 9篇 |
一般工业技术 | 49篇 |
冶金工业 | 79篇 |
原子能技术 | 2篇 |
自动化技术 | 59篇 |
出版年
2023年 | 6篇 |
2022年 | 16篇 |
2021年 | 17篇 |
2020年 | 16篇 |
2019年 | 20篇 |
2018年 | 16篇 |
2017年 | 21篇 |
2016年 | 16篇 |
2015年 | 17篇 |
2014年 | 34篇 |
2013年 | 50篇 |
2012年 | 30篇 |
2011年 | 51篇 |
2010年 | 29篇 |
2009年 | 36篇 |
2008年 | 29篇 |
2007年 | 32篇 |
2006年 | 20篇 |
2005年 | 20篇 |
2004年 | 14篇 |
2003年 | 19篇 |
2002年 | 11篇 |
2001年 | 3篇 |
2000年 | 10篇 |
1999年 | 9篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 10篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 6篇 |
1987年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1968年 | 2篇 |
1965年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有626条查询结果,搜索用时 15 毫秒
1.
Malik Mary L.; Beutler Larry E.; Alimohamed Shabia; Gallagher-Thompson Dolores; Thompson Larry 《Canadian Metallurgical Quarterly》2003,71(1):150
The definition of an empirically supported treatment (EST) arguably embodies 2 untested assumptions: (a) that different manualized renditions of the same therapy are functionally equivalent and (b) that therapies can be reliably applied independently of therapist, setting, and format. These assumptions were tested as applied to cognitive therapy (CT), using process data from a large multisite study (N=235) that included 3 cognitive and 6 alternative therapies. Although the non-CTs were more variable than the CTs on 2 of 4 dimensions studied (directiveness and emotional arousal), there was considerable variation among the 3 CTs, even when implemented in the current context of rigorous training, manualization, and adherence checks. Results are discussed as related to the assumptions underlying EST criteria. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
2.
Luis Moreno Santiago Garrido Dolores Blanco M. Luisa Muñoz 《Robotics and Autonomous Systems》2009,57(4):441-450
A new solution to the Simultaneous Localization and Modelling problem is presented in this paper. The algorithm is based on the stochastic search for solutions in the state space to the global localization problem by means of a differential evolution algorithm. This non linear evolutive filter, called Evolutive Localization Filter (ELF), searches stochastically along the state space for the best robot pose estimate. The set of pose solutions (the population) focuses on the most likely areas according to the perception and up to date motion information. The population evolves using the log-likelihood of each candidate pose according to the observation and the motion errors derived from the comparison between observed and predicted data obtained from the probabilistic perception and motion model.The proposed SLAM algorithm operates in two steps: in the first step the ELF filter is used at local level to re-localize the robot based on the robot odometry, the laser scan at a given position and a local map where only a low number of the last scans have been integrated. In the second step, the aligned laser measures and the corrected robot poses are used to detect whether the robot is revisiting a previously crossed area (i.e., a cycle in the robot trajectory exists). Once a cycle is detected, the Evolutive Localization Filter is used again to estimate the accumulated residual drift in the detected loop and then to re-estimate the robot poses in order to integrate the sensor measures in the global map of the environment.The algorithm has been tested in different environments to demonstrate the effectiveness, robustness and computational efficiency of the proposed approach. 相似文献
3.
Claudio Ferraro Esther Garcia‐Tuñon Victoria G. Rocha Suelen Barg Maria Dolores Fariñas Tomas E. Gomez Alvarez‐Arenas Giorgio Sernicola Finn Giuliani Eduardo Saiz 《Advanced functional materials》2016,26(10):1636-1645
The directional freezing of microfiber suspensions is used to assemble highly porous (porosities ranging between 92% and 98%) SiC networks. These networks exhibit a unique hierarchical architecture in which thin layers with honeycomb‐like structure and internal strut length in the order of 1–10 μm in size are aligned with an interlayer spacing ranging between 15 and 50 μm. The resulting structures exhibit strengths (up to 3 MPa) and stiffness (up to 0.3 GPa) that are higher than aerogels of similar density and comparable to other ceramic microlattices fabricated by vapor deposition. Furthermore, this wet processing technique allows the fabrication of large‐size samples that are stable at high temperature, with acoustic impedance that can be manipulated over one order of magnitude (0.03–0.3 MRayl), electrically conductive and with very low thermal conductivity. The approach can be extended to other ceramic materials and opens new opportunities for the fabrication of ultralight structures with unique mechanical and functional properties in practical dimensions. 相似文献
4.
Miriam Ortega Heras M. Dolores Rivero-Pérez Silvia Pérez-Magariño Carlos González-Huerta Mª Luisa González-Sanjosé 《European Food Research and Technology》2008,226(6):1485-1493
Microoxygenation is a wine-making technique consisting in the addition of small and controlled amounts of oxygen. This study
has examined the effect of this technique on the volatile composition of two red single variety wines during two successive
vintages. The microoxygenation treatment was applied at the end of alcoholic fermentation and before beginning malolactic
fermentation. Once the microoxygenation treatment had finished, wines were aged in new American oak barrels for 12 months.
The results obtained showed that the microoxygenation treatment did not cause significant changes in the varietal and fermentation
volatile compounds, however microoxygenation slowed down the extraction of some of the volatile compounds extracted from wood.
A varietal and vintage effect was also observed for some of the compounds studied. 相似文献
5.
The effect of including distilled rosemary leaf in the diet of pregnant ewes on subsequent lamb meat quality was studied. Thirty-six Segureña ewes were randomly assigned to three homogeneous groups. One group was fed a basal diet (BD) as control while the diet of the other two groups was modified by substituting 10% (R1) and 20% (R2) of the BD with a pellet made from 50% barley and 50% of distilled rosemary leaves (DRL). Meat spoilage (TVC, PSY and MYC), TBARS, CIELab coordinates and the sensory characteristics contribution of fresh lamb meat packed in MAP (70% O2:30% CO2) were analyzed on days 0, 7, 14 and 21. In general, R1 and R2 had higher a* values, better scores for meat and fat colour (P < 0.05) and lower TBARS and rancid odour (P < 0.05), than the control samples. The total viable count was lower in meat DRL. No statistically significant differences were detected between the two treatments (10–20% DRL). 相似文献
6.
Apparent chemical composition of nine commercial or semi-commercial whey protein concentrates, isolates and fractions 总被引:2,自引:0,他引:2
Carl Holt Deborah McPhail Ian Nevison Tommy Nylander Jeanette Otte Richard H. Ipsen Rogert Bauer Lars gendal Kees Olieman Kees G. de Kruif Joëlle Léonil Daniel Mollé Gwénaële Henry Jean Louis Maubois M. Dolores Pérez Pilar Puyol Miguel Calvo Stella M. Bury George Kontopidis Iain McNae Lindsay Sawyer Laura Ragona Lucia Zetta Henriette Molinari Bert Klarenbeek Margrethe J. Jonkman Jacques Moulin & Dereck Chatterton 《International Journal of Food Science & Technology》1999,34(5-6):543-556
Summary Analytical results are given for whey powders prepared on a commercial or semi-commercial scale by three companies. Altogether, five preparations enriched in β-lactoglobulin, four whey protein isolates and a fraction enriched in α-lactalbumin were analyzed for protein composition, including %β-lactoglobulin, α-lactalbumin, bovine serum albumin, casein (glyco) macropeptide and the main triglycerides. Protein composition was determined by high pressure gel permeation and reversed phase liquid chromatography and by capillary zone electrophoresis. The extent of modification of the native β-lactoglobulin structure was also measured through the degree of lactosylation and the fraction of accessible free sulphydryl groups. One significant finding was that the calculated recovery of protein following quantitation of the chromatogram or electropherogram was seldom above 90% and occasionally below 60% of that loaded onto the column or capillary, raising doubts as to the reliability of the analytical results. Extrapolation by linear regression to 100% recovery allowed estimates to be made of the true β-lactoglobulin composition of the samples. The nine samples could be placed into three distinct groups with estimated true β-lactoglobulin weight % of 70.9 ± 1.1, 62.0 ± 3.4 and 39.5 ± 4.9. Physico-chemical properties of the group of samples are reported elsewhere (Holt et al ., 1999). 相似文献
7.
Josefa Madrid M Dolores Megías Fuensanta Hernndez 《Journal of the science of food and agriculture》1999,79(4):580-584
A simple, rapid and sensitive capillary gas chromatographic method was investigated to determine volatile fatty acids (VFA) in juice from silage made from artichoke and orange byproducts. The procedure uses a capillary column fused‐silica, 30 m×0.25 mm×0.25 mm ID and coated with FFAP‐TR. Centrifuged samples can be injected directly after lowering the pH to 1 and using a simple deproteinisation method. No adsorption, tailing or ghost phenomena occured. Separate analyses of VFA are quick and reliable. The average duration of an analyses is 7 min. The concentration, not only of the major acids, such as acetic acid, but also of the minor fermentation products such as butyric acid can be determined. The retention times of the products of fermentation and the extraction reagents were sufficiently different to avoid interference problems. © 1999 Society of Chemical Industry 相似文献
8.
Niamh Harbourne Eunice Marete Jean Christophe Jacquier Dolores O'Riordan 《Food research international (Ottawa, Ont.)》2013,50(2):480-486
Recently phytochemical constituents have attracted a lot of interest as sources of functional ingredients in food product formulations. However, before being incorporated into foods or beverages the stability of these bioactive constituents during post-harvest preservation procedures, in food matrices and during processing and storage must be considered. This review will focus on the stability of phytochemical constituents of herbs with anti-inflammatory properties, including chamomile, meadowsweet, feverfew and willow. These herbs contain a relatively high content of phenolic compounds in comparison to common fruits and vegetables. They have been traditionally used to make teas or infusions that are consumed as a remedy for pain and inflammation. Effects of preservation and extraction conditions on the level of bioactive constituents will be reviewed. The storage conditions (temperature) and thermal processing at pH levels encountered in food products will also be examined. 相似文献
9.
The aim was to study spoilage during the refrigerated storage of cooked pork loin processed by the sous vide method. Samples were packaged under vacuum into polyamide-polypropylene pouches, cooked at an oven temperature/time of 70 °C/12 h, chilled at 3 °C and stored at 2 °C for 0, 5 or 10 weeks. Microbial (psychrotrophs, lactic acid bacteria, Enterobacteriaceae, moulds and yeasts), physical–chemical (pH, water activity, TBARS, acidity, L*a*b* colour, texture profile analysis and shear force) and sensory (appearance, odour, flavour, texture and acceptance) parameters were determined. The results showed that sensory spoilage preceded microbiological spoilage of sous vide pork loin. Counts bellow 1 log cfu/g of psychrotrophs, anaerobic psychrotrophs, Enterobacteriaceae and lactic acid bacteria were detected in any control week, while moderate counts (2–3 log cfu/g) of moulds and yeasts were found. Minor changes in water activity, lipid oxidation, CIELab colour, hardness, cohesiveness or gumminess were associated with spoilage of pork loin, only decreases of lactic acid, springiness and shear force were observed. The pork loin was unacceptable after 10 weeks. This loss of acceptance was mainly due to the deterioration of meaty flavour and odour, although the loss of appearance, juiciness and firmness also contributed. Moderate warmed-over and rancidity were detected. The sensory analysis was the most effective method for determining the shelf life of the sous vide pork-based dishes. 相似文献
10.