全文获取类型
收费全文 | 3999篇 |
免费 | 281篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 51篇 |
综合类 | 1篇 |
化学工业 | 1248篇 |
金属工艺 | 151篇 |
机械仪表 | 118篇 |
建筑科学 | 90篇 |
矿业工程 | 19篇 |
能源动力 | 172篇 |
轻工业 | 753篇 |
水利工程 | 16篇 |
石油天然气 | 12篇 |
武器工业 | 1篇 |
无线电 | 186篇 |
一般工业技术 | 710篇 |
冶金工业 | 108篇 |
原子能技术 | 14篇 |
自动化技术 | 635篇 |
出版年
2023年 | 40篇 |
2022年 | 132篇 |
2021年 | 244篇 |
2020年 | 136篇 |
2019年 | 156篇 |
2018年 | 220篇 |
2017年 | 207篇 |
2016年 | 243篇 |
2015年 | 196篇 |
2014年 | 257篇 |
2013年 | 431篇 |
2012年 | 268篇 |
2011年 | 217篇 |
2010年 | 176篇 |
2009年 | 202篇 |
2008年 | 148篇 |
2007年 | 134篇 |
2006年 | 89篇 |
2005年 | 62篇 |
2004年 | 68篇 |
2003年 | 70篇 |
2002年 | 53篇 |
2001年 | 32篇 |
2000年 | 34篇 |
1999年 | 21篇 |
1998年 | 28篇 |
1997年 | 20篇 |
1996年 | 15篇 |
1995年 | 19篇 |
1994年 | 16篇 |
1993年 | 13篇 |
1992年 | 9篇 |
1991年 | 8篇 |
1990年 | 22篇 |
1989年 | 12篇 |
1988年 | 12篇 |
1987年 | 14篇 |
1986年 | 14篇 |
1985年 | 21篇 |
1984年 | 32篇 |
1983年 | 33篇 |
1982年 | 23篇 |
1981年 | 23篇 |
1980年 | 26篇 |
1979年 | 21篇 |
1978年 | 8篇 |
1977年 | 12篇 |
1976年 | 9篇 |
1974年 | 7篇 |
1973年 | 10篇 |
排序方式: 共有4285条查询结果,搜索用时 15 毫秒
121.
The polyphenolic components of Idared and Shampion apple purées were determined by HPLC; chlorogenic acid was the most abundant acid (20.0 mg/100 g in microwaved Idared); other polyphenols identified in high concentrations included (−)-epicatechin, procyanidin B1 and B2; quercetin and cyanidin glycosides were found in minor concentrations. The Shampion purées had higher total phenolics (142 mg/100 g) and procyanidin B2 concentrations (17.3 mg/100 g) than the Idared ones, and polymeric procyanidins represented 41% of all polyphenols. Antioxidant capacities of the samples, determined by spectrophotometric methods and EPR spectroscopy, correlated well with the concentration of polyphenols. The antioxidant properties could be better represented by EPR than by UV–vis measurements. The latter require transparent (clear) samples whereas EPR can be a method of choice in the assessment of radical-scavenging activity of dense and cloudy apple purées. Our results support the putative high antioxidant value of apple purées and define their capacity in terms of the major constituents. Apple purées are a rich source of natural antioxidants, especially of chlorogenic acid and procyanidins. 相似文献
122.
123.
124.
Kała Katarzyna Maślanka Anna Sułkowska-Ziaja Katarzyna Rojowski Jacek Opoka Włodzimierz Muszyńska Bożena 《Food science and biotechnology》2016,25(3):829-837
Food Science and Biotechnology - The objective of this study was to obtain the in vitro cultures of Boletus badius under controlled conditions and investigate the release of indole compounds and... 相似文献
125.
Gloria Urbano Sławomir Frejnagel Jesús M. Porres Pilar Aranda Elena Gomez-Villalva Juana Frías María López-Jurado 《European Food Research and Technology》2007,226(1-2):105-111
The effect of dephytinization of Pisum sativum, L. flour on the bioavailability of Mg and Zn was evaluated in growing rats. Processing of legume flours under optimal conditions
for phytase activity (pH 5.5, 37 °C, 60 min) and subsequent removal of the soaking solution led to a 42 and 61% reduction
in the content of Mg and Zn, respectively. Treatment with phytase led to an additional reduction in the concentration of the
above-mentioned seed flour components, compared to the raw pea flour (69% and 74% for Mg and Zn, respectively). The considerable
reduction in the content of inositol phosphates with high degree of phosphorylation attained under both processing conditions
did not affect the digestive utilization of Mg, whereas the metabolic utilization of this mineral increased significantly.
The digestive and metabolic utilization of Zn increased significantly in response to both processes assayed, reaching the
highest values in the experimental group that was fed the phytase-treated pea flour diet. The amount of Mg retained by the
experimental animals was reflected in the content of this mineral in the different tissues studied (femur, sternum, kidney,
and heart), whereas no correlation was found in the case of Zn. 相似文献
126.
Gloria Urbano María López‐Jurado Jesús M Porres Sławomir Frejnagel Elena Gómez‐Villalva Juana Frías Concepción Vidal‐Valverde Pilar Aranda 《Journal of the science of food and agriculture》2007,87(7):1356-1363
The effect of treatment with α‐galactosidase, tannase or a cell‐wall‐degrading enzyme complex under optimal conditions of pH, temperature and length of incubation time on the chemical composition and nutritive utilisation of protein and carbohydrates from pea (Pisum sativum L.) flour was studied. Soaking of pea flours in combination with enzyme treatment led to reductions of 77–90% in the levels of α‐galactosides, and of 60–80% in the levels of trypsin inhibitor activity, increasing the content of total available sugars, which was highest in the pea flour treated with the cell‐wall‐degrading enzyme complex. All the treatments assayed caused a significant improvement in daily food intake, whereas the nutritive utilisation of protein was not increased in any of the pea products tested when compared to the raw pea flour. However, all the soaking and enzymatic treatments led to a significant improvement in daily weight gain associated with a higher dietary intake of food and total available sugars. Copyright © 2007 Society of Chemical Industry 相似文献
127.
Stanisław Sieniutycz 《国际自然能源杂志》2013,34(1):46-56
This research continues the thermodynamic analysis of steady-state solid oxide fuel cells initiated in Sieniutycz (Sieniutycz, S., 2010, Thermodynamic aspects of power generation in imperfect fuel cells: part I. International Journal of Ambient Energy, 31 (4), 195–202). This analysis focuses on the effect of incomplete conversions in chemical reactions. A general approach is developed that attributes lowering of the cell voltage below its reversible value to polarisations and imperfect chemical conversions. Relevant model, appropriate for systems with complete conversions, is extended to imperfect cases. The performance curves of a fuel cell and the effect of typical design and operating parameters on the cell behaviour are analysed. A general result is obtained for power limits of fuel cells propelled by linear transport phenomena. 相似文献
128.
Edyta Wgowska Maria Koziokiewicz Daria Kamiska Bartomiej Grobelski Dariusz Paweczak Marek Koodziejczyk Stanisaw Bielecki Edyta Gendaszewska-Darmach 《International journal of molecular sciences》2022,23(1)
Chronic wound healing is currently a severe problem due to its incidence and associated complications. Intensive research is underway on substances that retain their biological activity in the wound microenvironment and stimulate the formation of new blood vessels critical for tissue regeneration. This group includes synthetic compounds with proangiogenic activity. Previously, we identified phosphorothioate analogs of nucleoside 5′-O-monophosphates as multifunctional ligands of P2Y6 and P2Y14 receptors. The effects of a series of unmodified and phosphorothioate nucleotide analogs on the secretion of VEGF from keratinocytes and fibroblasts, as well as their influence on the viability and proliferation of keratinocytes, fibroblasts, and endothelial cells were analyzed. In addition, the expression profiles of genes encoding nucleotide receptors in tested cell models were also investigated. In this study, we defined thymidine 5′-O-monophosphorothioate (TMPS) as a positive regulator of angiogenesis. Preliminary analyses confirmed the proangiogenic potency of TMPS in vivo. 相似文献
129.
130.
Joanna Sikora Aleksandra Karczmarska-Wdzka Joanna Bugieda Przemysaw Sobczak 《International journal of molecular sciences》2022,23(3)
Ischemic stroke is a disease related to abnormal blood flow that leads to brain dysfunction. The early and late phases of the disease are distinguished. A distinction is made between the early and late stages of the disease, and the best effect in treating an ischemic stroke is usually achieved within the first hours after the onset of symptoms. This review looked at studies platelet activity monitoring studies to determine the risks and benefits of various approaches including antiplatelet therapy. A study was conducted on recently published literature based on PRISMA. This review includes 32 research articles directly addressing the importance of monitoring platelet function during antiplatelet therapy (dual or monotherapy) after ischemic stroke. In patients with transient ischemic attack or ischemic stroke, antiplatelet therapy can reduce the risk of stroke by 11–15%, assuming that patients respond well. Secondary prevention results are dependent on platelet reactivity, meaning that patients do not respond equally to antiplatelet therapy. It is very important that aspirin-resistant patients can benefit from the use of dual antiplatelet therapy. The individualized approach to secondary stroke prevention is to administer the most appropriate drug at the correct dose and apply the optimal therapeutic procedure to the individual patient. 相似文献