全文获取类型
收费全文 | 5409篇 |
免费 | 163篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 19篇 |
综合类 | 3篇 |
化学工业 | 713篇 |
金属工艺 | 72篇 |
机械仪表 | 73篇 |
建筑科学 | 173篇 |
矿业工程 | 6篇 |
能源动力 | 105篇 |
轻工业 | 165篇 |
水利工程 | 43篇 |
石油天然气 | 29篇 |
无线电 | 246篇 |
一般工业技术 | 711篇 |
冶金工业 | 2705篇 |
原子能技术 | 15篇 |
自动化技术 | 497篇 |
出版年
2023年 | 40篇 |
2022年 | 64篇 |
2021年 | 104篇 |
2020年 | 77篇 |
2019年 | 87篇 |
2018年 | 89篇 |
2017年 | 79篇 |
2016年 | 90篇 |
2015年 | 80篇 |
2014年 | 116篇 |
2013年 | 211篇 |
2012年 | 176篇 |
2011年 | 240篇 |
2010年 | 158篇 |
2009年 | 143篇 |
2008年 | 168篇 |
2007年 | 154篇 |
2006年 | 128篇 |
2005年 | 93篇 |
2004年 | 82篇 |
2003年 | 93篇 |
2002年 | 64篇 |
2001年 | 46篇 |
2000年 | 48篇 |
1999年 | 110篇 |
1998年 | 680篇 |
1997年 | 447篇 |
1996年 | 263篇 |
1995年 | 163篇 |
1994年 | 155篇 |
1993年 | 152篇 |
1992年 | 63篇 |
1991年 | 65篇 |
1990年 | 57篇 |
1989年 | 68篇 |
1988年 | 57篇 |
1987年 | 67篇 |
1986年 | 32篇 |
1985年 | 40篇 |
1984年 | 24篇 |
1983年 | 32篇 |
1982年 | 35篇 |
1981年 | 26篇 |
1980年 | 34篇 |
1979年 | 25篇 |
1978年 | 31篇 |
1977年 | 77篇 |
1976年 | 126篇 |
1975年 | 18篇 |
1973年 | 14篇 |
排序方式: 共有5575条查询结果,搜索用时 15 毫秒
61.
Rachel E. Brimelow Nicholas P. West Lauren T. Williams Allan W. Cripps 《Critical reviews in food science and nutrition》2017,57(8):1593-1602
Obesity is a strong predictive factor in the development of chronic disease and has now superseded undernutrition as a major public health issue. Chronic inflammation is one mechanism thought to link excess body weight with disease. Increasingly, the gut and its extensive population of commensal microflora are recognized as playing an important role in the development of obesity-related chronic inflammation. Obesity and a high fat diet are associated with altered commensal microbial communities and increased intestinal permeability which contributes to systemic inflammation as a result of the translocation of lipopolysaccharide into the circulation and metabolic endotoxemia. Various milk proteins are showing promise in the prevention and treatment of obesity and chronic low-grade inflammation via reductions in visceral fat, neutralization of bacteria at the mucosa and reduced intestinal permeability. In this review, we focus on evidence supporting the potential antiobesogenic and anti-inflammatory effects of bovine whey-derived lactoferrin and immunoglobulins. 相似文献
62.
The antioxidant effectiveness of different hydroxycinnamic acids for inhibiting the formation of off-flavours associated to rancidity in minced frozen horse mackerel white muscle stored at −10 and −18 °C was studied. The influence of lipid oxidation on protein aggregation, protein denaturation and water holding capacity was also determined. Caffeic acid, o-coumaric acid and ferulic acid were the antioxidants tested. The order of antioxidant effectiveness was caffeic acid > ferulic acid > o-coumaric acid accordingly with previous results obtained in chilled horse mackerel. A strong dependence of antioxidant effectiveness to the ratio lipid/antioxidant concentration was observed. There was no evidence to suggest that antioxidants reduce protein aggregation or water holding capacity changes. Protein aggregation was not accompanied by gross protein denaturation, as monitored by differential scanning calorimetry. No evidence was found for a link between extent of lipid oxidation and degree of protein aggregation or water holding capacity changes. 相似文献
63.
64.
A light and electron microscopic study was carried out in 21 infants in whom the pathologic diagnosis of bronchopulmonary dysplasia had been made. All the infants except two had the respiratory distress syndrome at birth, and all 21 had been treated with respirator and oxygen therapy for various periods of time. The pathologic alterations observed in all the infants studied were primarily damage of the bronchial and bronchiolar ciliary apparatus and mucous membranes, severe necrotizing bronchiolitis, and marked bronchiolar and alveolar fibrosis. These changes were more pronounced in infants who survived the longest period of time. Such inflammatory and fibrotic changes are known to predispose to destruction of lung tissue, emphysema, and pulmonary hypertension. Six of these 21 infants developed symptoms and signs of cardiac atrial or ventricular stress, including cor pulmonale, prior to their demise. These infants were among those that survived the longest periods of time, had the longest exposure to supplemental oxygen, and showed histopathologically severe pulmonary fibrosis and emphysema. 相似文献
65.
66.
MJ Withers GV McCahill PD Griffiths RB Heath JR Pattison DS Dane 《Canadian Metallurgical Quarterly》1976,29(8):732-735
Two passive haemagglutination methods for detecting HBsAg were compared. In general, the method using turkey erythrocytes was found preferable to the method employing sheep cells since it is more rapid and more sensitive, and less frequently gave rise to false positive reactions with sera from staff, blood donors, and patients not receiving haemodialysis. The turkey cell test gives rise to more false positive screen tests than the sheep cell test when monitoring renal dialysis patients since approximately 10% of the sera of these patients were found to contain turkey cell agglutinins, but this presents no particular difficulty if the recommended absorption procedures are used. 相似文献
67.
From the results of this study, it appears that whole blood alone or red blood cells reconstituted with saline solution do not adequately replace the loss of albumin and concomitant decrease in colloid oncotic pressure that occur during extensive intraabdominal and intrathoracic operations. Since colloid oncotic pressure is a major factor in the restitution of intravascular volume from stores of interstitial fluid and since it may also play a role in the development of postoperative pulmonary problems, it is important to maintain a relatively normal colloid oncotic pressure during the operation and in the immediate postoperative period. Although dextran can be used for this purpose, its short half-life of four to six hours and associated coagulation problems militate against its use in large quantities. This leaves purified protein fraction or salt-poor albumin as the main sources of protein for the maintenance of colloid oncotic pressure. Both of these products are expensive and short in supply. The oncometer in present use is a clinically feasible and rapid, one to three minutes, means of determining the colloid oncotic pressure. It permits a rational approach to the use of albumin products, avoiding the pitfalls of under or excess administration in the operative and postoperative periods. 相似文献
68.
VK Naik AN Thakur AR Sheth UM Joshi SS Rao DS Pardanani JK Kulsreshtha RK Handa 《Canadian Metallurgical Quarterly》1976,48(2):441-442
The testosterone concentration in allantoic fluid between 90 and 150 days of gestation in cattle can be used to determine the fetal sex; values were 442 +/- 20-3 (S.E.M.) pg testosterone/ml for males fetuses and 215 +/- 8-2 pg/ml for female fetuses. 相似文献
69.
70.
Black soybean is a potential functional food ingredient with high anthocyanin content, but the ability to maintain anthocyanin content under dry heat processing has not been reported. This study investigated the effects of soybean seed coat colour and baking time–temperature combinations on the extractable antioxidant properties of a soy cracker food model. Crackers prepared with black soybeans had significantly higher TPC, total isoflavones, and peroxyl, hydroxyl, and ABTS+ radical scavenging abilities than their yellow counterparts, at all time–temperature combinations. Cyanidin-3-glucoside (C3G) was detected only in black soybean crackers, and all baking treatments significantly decreased C3G. The greatest losses occurred at the low temperature × long time and high temperature × short time, the smallest loss with moderate temperature × short/medium time. The high temperature treatment altered phenolic acid and isoflavone profiles; however, total isoflavones were unaffected. Overall results suggest that moderate baking temperature at minimal time may best preserve anthocyanin and other phenolics in baked black soybean crackers. 相似文献