全文获取类型
收费全文 | 2920篇 |
免费 | 144篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 35篇 |
综合类 | 6篇 |
化学工业 | 672篇 |
金属工艺 | 26篇 |
机械仪表 | 73篇 |
建筑科学 | 73篇 |
矿业工程 | 4篇 |
能源动力 | 67篇 |
轻工业 | 537篇 |
水利工程 | 22篇 |
石油天然气 | 6篇 |
无线电 | 190篇 |
一般工业技术 | 349篇 |
冶金工业 | 535篇 |
原子能技术 | 29篇 |
自动化技术 | 442篇 |
出版年
2024年 | 4篇 |
2023年 | 22篇 |
2022年 | 127篇 |
2021年 | 112篇 |
2020年 | 50篇 |
2019年 | 53篇 |
2018年 | 72篇 |
2017年 | 65篇 |
2016年 | 94篇 |
2015年 | 76篇 |
2014年 | 105篇 |
2013年 | 160篇 |
2012年 | 157篇 |
2011年 | 173篇 |
2010年 | 119篇 |
2009年 | 125篇 |
2008年 | 100篇 |
2007年 | 105篇 |
2006年 | 97篇 |
2005年 | 70篇 |
2004年 | 62篇 |
2003年 | 78篇 |
2002年 | 67篇 |
2001年 | 45篇 |
2000年 | 50篇 |
1999年 | 58篇 |
1998年 | 194篇 |
1997年 | 136篇 |
1996年 | 95篇 |
1995年 | 65篇 |
1994年 | 56篇 |
1993年 | 44篇 |
1992年 | 14篇 |
1991年 | 19篇 |
1990年 | 12篇 |
1989年 | 16篇 |
1988年 | 10篇 |
1987年 | 11篇 |
1986年 | 16篇 |
1985年 | 12篇 |
1984年 | 13篇 |
1983年 | 15篇 |
1982年 | 12篇 |
1981年 | 12篇 |
1980年 | 11篇 |
1979年 | 4篇 |
1978年 | 8篇 |
1977年 | 14篇 |
1976年 | 15篇 |
1973年 | 3篇 |
排序方式: 共有3066条查询结果,搜索用时 0 毫秒
91.
Extract of Salicornia europaea in fresh pasta to enhance phenolic compounds and antioxidant activity
Lucia Padalino Cristina Costa Matteo Alessandro Del Nobile Amalia Conte 《International Journal of Food Science & Technology》2019,54(11):3051-3057
Extract from Salicornia europaea was added to durum wheat fresh pasta. Sensory properties, cooking quality, microbiological stability, content in bioactive compounds and antioxidant activity, before and after pasta digestion were studied. The extract was obtained by ultrasound-assisted extraction. From the technological point of view the extract did not affect pasta dough and the cooking parameters and sensory properties of the enriched samples were found similar to the control pasta. No antimicrobial effect was exerted by the extract. From the chemical point of view interesting findings were recorded for pasta before and after digestion. Specifically, data of bioaccessible fraction of digested sample showed a significantly higher amount of total phenols and flavonoid content (11.52 mg gallic acid g−1 and 0.55 mg quercetin g−1 respectively) than digested control pasta (9.54 mg gallic acid g−1 and 0.23 mg quercetin g−1 respectively). The antioxidant activity of enriched sample also increased compared to the control pasta (6.20 vs. 2.50 μmoles FeSO4 g−1). 相似文献
92.
Isabel M Martín Del Molino Brbara Rojo Rafael Martinez-Carrasco Pilar Prez 《Journal of the science of food and agriculture》1988,42(1):29-37
The changes in the composition of free and total amino acids in wheat grain during development are described: the experiment was performed in a growth chamber with three varieties of winter wheat (Triticum aestivum L.): Splendeur, Hobbit and Maris Huntsman. The changes in the total composition of amino acids of the grain as development progressed were consistent with an increase in the proportion of storage proteins. At 15 days after anthesis, the relative amount of glycine increased, suggesting that at this moment the proportion of gliadins was relatively low. The relative amount of arginine increased in mature grain, showing that at times close to maturity the relative proportion of synthesis of a protein fraction rich in this amino acid increased. Free glutamate, proline and arginine decreased at 15 days to a greater extent than the other amino acids and was present in low relative amounts during the period of maximum protein synthesis in the grain; these three amino acids could be the most limiting for protein synthesis in grain. In the free fraction the following showed a similar pattern of change during grain development: aspartate, arginine and histidine on the one hand, and on the other alanine, valine, leucine, isoleucine, threonine, phenylalanine and tyrosine; moreover both groups were inversely correlated. Glycine and lysine were directly related to each other and inversely to glutamate. 相似文献
93.
Annurca (Malus pumila Miller cv. Annurca) apple as a functional food for the contribution to a healthy balance of plasma cholesterol levels: results of a randomized clinical trial 下载免费PDF全文
94.
A comprehensive meta‐analysis on dietary flavonoid and lignan intake and cancer risk: Level of evidence and limitations 下载免费PDF全文
95.
Phenyl‐γ‐valerolactones,flavan‐3‐ol colonic metabolites,protect brown adipocytes from oxidative stress without affecting their differentiation or function 下载免费PDF全文
96.
Del Favero S Facchinetti A Cobelli C 《IEEE transactions on bio-medical engineering》2012,59(5):1281-1290
In diabetes, the mean square error (MSE) metric is extensively used for assessing glucose prediction methods and identifying glucose models. One limitation of this metric is that, by equally treating errors in hypo-, eu-, and hyperglycemia, it is not able to weight the different clinical impact of errors in these three situations. In this paper, we propose a new cost function, which overcomes this limitation and can be used in place of MSE for several scopes, in particular for assessing the quality of glucose predictors and identifying glucose models. The new metric called glucose-specific MSE (gMSE) modifies MSE with a Clark error grid inspired penalty function, which penalizes overestimation in hypoglycemia and underestimation in hyperglycemia, i.e., the most harmful conditions on a clinical perspective. From a mathematical point of view, gMSE retains sensitivity of MSE and inherits some of its important mathematical features, in particular it has no local minima, simplifying the optimization. This makes it suitable for model identification purposes also. First, the goodness of it is demonstrated by means of three experiments, designed ad hoc to evidence its sensitivity to accuracy, precision, and distortion in glucose predictions. Second, a prediction assessment problem is presented, in which two real prediction profiles are compared. Results show that the MSE chooses the worst clinical situation, while gMSE correctly selects the situation with less clinical risk. Finally, we also demonstrate that models identified minimizing gMSE are more accurate in potentially harmful situations (hypo- and hyperglycemia) than those obtained by MSE. 相似文献
97.
Scherm B Palomba M Serra D Marcello A Migheli Q 《International journal of food microbiology》2005,98(2):201-210
98.
Effects of UV exclusion on the physiology and phenolic composition of leaves and berries of Vitis vinifera cv. Graciano 下载免费PDF全文
99.
Del Bas JM Ricketts ML Baiges I Quesada H Ardevol A Salvadó MJ Pujadas G Blay M Arola L Bladé C Moore DD Fernandez-Larrea J 《Molecular nutrition & food research》2008,52(10):1172-1181
Hypertriglyceridemia is an independent risk factor in the development of cardiovascular diseases, and we have previously reported that oral administration of a grape seed procyanidin extract (GSPE) drastically decreases plasma levels of triglycerides (TG) and apolipoprotein B (ApoB) in normolipidemic rats, with a concomitant induction in the hepatic expression of the nuclear receptor small heterodimer partner (NR0B2/SHP). Our objective in this study was to elucidate whether SHP is the mediator of the reduction of TG-rich ApoB-containing lipoproteins triggered by GSPE. We show that GSPE inhibited TG and ApoB secretion in human hepatocarcinoma HepG2 cells and had and hypotriglyceridemic effect in wild-type mouse. The TG-lowering action of GSPE was abolished in HepG2 cells transfected with a SHP-specific siRNA and in a SHP-null mouse. Moreover, in mouse liver, GSPE downregulated several lipogenic genes, including steroid response element binding protein 1c (SREBP-1c), and upregulated carnitine palmitoyltransferase-1A (CPT-1A) and apolipoprotein A5 (ApoA5), in a SHP-dependent manner. In HepG2 cells GSPE also inhibited ApoB secretion, but in a SHP-independent manner. In conclusion, SHP is a key mediator of the hypotriglyceridemic response triggered by GSPE. This novel signaling pathway of procyanidins through SHP may be relevant to explain the health effects ascribed to the regular consumption of dietary flavonoids. 相似文献
100.
RF Del Maestro 《Canadian Metallurgical Quarterly》1998,89(5):874-887
The human race has always contemplated the question of the anatomical location of the soul. During the Renaissance the controversy crystallized into those individuals who supported the heart ("cardiocentric soul") and others who supported the brain ("cephalocentric soul") as the abode for this elusive entity. Leonardo da Vinci (1452-1519) joined a long list of other explorers in the "search for the soul." The method he used to resolve this anatomical problem involved the accumulation of information from ancient and contemporary sources, careful notetaking, discussions with acknowledged experts, and his own personal search for the truth. Leonardo used a myriad of innovative methods acquired from his knowledge of painting, sculpture, and architecture to define more clearly the site of the "senso comune"--the soul. In this review the author examines the sources of this ancient question, the knowledge base tapped by Leonardo for his personal search for the soul, and the views of key individuals who followed him. 相似文献