全文获取类型
收费全文 | 1863篇 |
免费 | 145篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 723篇 |
金属工艺 | 28篇 |
机械仪表 | 39篇 |
建筑科学 | 42篇 |
能源动力 | 39篇 |
轻工业 | 468篇 |
水利工程 | 9篇 |
石油天然气 | 10篇 |
无线电 | 72篇 |
一般工业技术 | 263篇 |
冶金工业 | 108篇 |
原子能技术 | 9篇 |
自动化技术 | 194篇 |
出版年
2024年 | 4篇 |
2023年 | 21篇 |
2022年 | 97篇 |
2021年 | 189篇 |
2020年 | 61篇 |
2019年 | 68篇 |
2018年 | 65篇 |
2017年 | 57篇 |
2016年 | 78篇 |
2015年 | 70篇 |
2014年 | 81篇 |
2013年 | 155篇 |
2012年 | 105篇 |
2011年 | 135篇 |
2010年 | 100篇 |
2009年 | 109篇 |
2008年 | 107篇 |
2007年 | 78篇 |
2006年 | 54篇 |
2005年 | 35篇 |
2004年 | 41篇 |
2003年 | 33篇 |
2002年 | 24篇 |
2001年 | 19篇 |
2000年 | 17篇 |
1999年 | 23篇 |
1998年 | 19篇 |
1997年 | 14篇 |
1996年 | 14篇 |
1995年 | 9篇 |
1994年 | 12篇 |
1993年 | 13篇 |
1992年 | 13篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1966年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有2011条查询结果,搜索用时 31 毫秒
1.
Casalaro Giuseppina Lucia Cattivera Giulio Ciccozzi Federico Malavolta Ivano Wortmann Andreas Pelliccione Patrizio 《Software and Systems Modeling》2022,21(1):19-49
Software and Systems Modeling - Mobile robots operate in various environments (e.g. aquatic, aerial, or terrestrial), they come in many diverse shapes and they are increasingly becoming parts of... 相似文献
2.
3.
Gina Cavaliere Giovanna Trinchese Nadia Musco Federico Infascelli Chiara De Filippo Vincenzo Mastellone Valeria Maria Morittu Pietro Lombardi Raffaella Tudisco Micaela Grossi Vincenzo Monda Monica I. Cutrignelli Antonietta Messina Serena Calabrò Heleena B. Moni Luigi Stradella Giovanni Messina Marcellino Monda Maria Pina Mollica 《Journal of dairy science》2018,101(3):1843-1851
Excessive energy intake may evoke complex biochemical processes characterized by inflammation, oxidative stress, and impairment of mitochondrial function that represent the main factors underlying noncommunicable diseases. Because cow milk is widely used for human nutrition and in food industry processing, the nutritional quality of milk is of special interest with respect to human health. In our study, we analyzed milk produced by dairy cows fed a diet characterized by a high forage:concentrate ratio (high forage milk, HFM). In view of the low n-6:n-3 ratio and high content of conjugated linoleic acid of HFM, we studied the effects of this milk on lipid metabolism, inflammation, mitochondrial function, and oxidative stress in a rat model. To this end, we supplemented for 4 wk the diet of male Wistar rats with HFM and with an isocaloric amount (82 kJ, 22 mL/d) of milk obtained from cows fed a diet with low forage:concentrate ratio, and analyzed the metabolic parameters of the animals. Our results indicate that HFM may positively affect lipid metabolism, leptin:adiponectin ratio, inflammation, mitochondrial function, and oxidative stress, providing the first evidence of the beneficial effects of HFM on rat metabolism. 相似文献
4.
Maria Grazia Basanisi Gianfranco La Bella Gaia Nobili Rosa Coppola Annita Maria Damato Maria Assunta Cafiero Giovanna La Salandra 《International Journal of Food Science & Technology》2020,55(3):1145-1150
The authenticity and traceability of meat products are issues of primary importance to ensure food safety. Unfortunately, food adulteration (e.g. the addition of inexpensive cuts to minced meat products) and mislabelling (e.g. the inclusion of meat from species other than those declared) happens frequently worldwide. The aim of this study was to apply a droplet digital PCR assay for the detection and quantification (copies μL−1) of the beef, pork, horse, sheep, chicken and turkey in meat products. The analysis conducted on commercial meat showed the presence of traces of DNA from other animal species than those declared. We show that the method is highly sensitive, specific and accurate (accuracy = 100%). This method could be adopted by competent food safety authorities to verify compliance with the labelling of meat products and to ensure quality and safety throughout the meat supply chain, from primary production to consumption. 相似文献
5.
The fission yeast Schizosaccharomyces pombe is an important model organism for the study of fundamental questions in eukaryotic cell and molecular biology. A plethora of cellular processes are membrane associated and/or dependent on the proper functioning of cellular membranes. Phospholipids are not only the basic building blocks of cellular membranes; they also serve as precursors to numerous signaling molecules. In this review, we describe the biosynthetic pathways leading to major S. pombe phospholipids, how these pathways are regulated, and what is known about degradation and turnover of fission yeast phospholipids. This review also addresses the synthesis, regulation and the role of water-soluble phospholipid precursors. The last chapter of the review is devoted to the use of S. pombe for the biotechnological production of value-added lipid molecules. 相似文献
6.
Ottavia Colombo Simona Villani Giovanna Pinelli Claudia Trentani Maurizia Baldi Orazio Tomarchio Anna Tagliabue 《Nutrition journal》2008,7(1):5
Background
Excess body fat is a major risk factor for disease primarily due to its endocrine activity. In recent years several criteria have been introduced to evaluate this factor. Nevertheless, treatment need is currently assessed only on the basis of an individual's Body Mass Index (BMI), calculated as body weight (in kg) divided by height in m2. The aim of our study was to determine whether application of the BMI, compared to adiposity-based criteria, results in underestimation of the number of subjects needing lifestyle intervention. 相似文献7.
Non-pinched, minimum energy solutions are important class of distillation designs that offer the potential advantage of a better trade-off between capital investment and operating costs. In this paper, two important tasks associated with non-pinched distillation designs are studied. Thus the novel contributions of this work to the literature are
- (1) A comprehensive methodology for finding non-pinched minimum energy designs.
- (2) Understanding of the reasons for the existence of non-pinched distillation designs.
8.
This work presents a numerical study of high-field degradation and reliability issues of AlGaAs/GaAs power HFETs. A commercial two-dimensional drift–diffusion tool is used to investigate electric-field distributions, the effects of electron capture at the device surface under hot-carrier conditions, and the impact of drain recess scaling on such effects. Wherever experimental data are available for direct comparison, a good match is observed with our simulations. The main results of this study are (1) a validation of the hypothesis that attributes the main high-field degradation effects to electron capture over the gate–drain access region, and (2) design indications pointing out to the possibility of a reverse correlation between the gate–drain breakdown voltage and the device hot-carrier reliability. 相似文献
9.
Investigated the development of spontaneous classificatory behavior in 5 chimpanzees (Pan troglodytes) tested at different ages and analyzed Ss' spontaneous constructive interactions with sets of logically structured objects. The results show that chimpanzees possess a natural capacity to react to similarities and differences among test stimuli and construct classes. The general progression of their classificatory development is very similar to that reported for human infants from 6 to 24 mo. In both species, classification progresses from constructing single classes by different properties of objects to constructing single classes by similar or identical properties of objects. In addition, like humans, older chimpanzees spontaneously coordinate relations of similarities between sets and construct 2 class-consistent groupings. Chimpanzees' results are compared with those from a similar study with capuchins and macaques. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
Rafael Gallego Lucia Comino Alberto Ruiz‐Cabello 《International journal for numerical methods in engineering》2006,66(12):1913-1933
In this paper, the material constant sensitivity boundary integral equation is presented, and its numerical solution proposed, based on boundary element techniques. The formulation deals with plane problems with general rectilinear anisotropy. Expressions for the computation of sensitivities for displacements, tractions, strains and stresses are derived, both for boundary and interior points. The sensitivities can be computed with respect to the bulk material properties or to the properties of part of the domain (inclusions, coatings, etc.). To assess the accuracy of the proposed approach, the computed results are compared to analytical ones derived from exact solutions obtained by complex potential theory, when possible, or finite difference derivatives otherwise. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献