全文获取类型
收费全文 | 1068篇 |
免费 | 62篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 25篇 |
化学工业 | 311篇 |
金属工艺 | 10篇 |
机械仪表 | 32篇 |
建筑科学 | 20篇 |
能源动力 | 30篇 |
轻工业 | 89篇 |
水利工程 | 10篇 |
石油天然气 | 3篇 |
无线电 | 130篇 |
一般工业技术 | 146篇 |
冶金工业 | 128篇 |
原子能技术 | 4篇 |
自动化技术 | 194篇 |
出版年
2024年 | 2篇 |
2023年 | 15篇 |
2022年 | 73篇 |
2021年 | 69篇 |
2020年 | 32篇 |
2019年 | 17篇 |
2018年 | 42篇 |
2017年 | 31篇 |
2016年 | 28篇 |
2015年 | 28篇 |
2014年 | 44篇 |
2013年 | 68篇 |
2012年 | 70篇 |
2011年 | 65篇 |
2010年 | 38篇 |
2009年 | 36篇 |
2008年 | 49篇 |
2007年 | 46篇 |
2006年 | 41篇 |
2005年 | 24篇 |
2004年 | 23篇 |
2003年 | 17篇 |
2002年 | 19篇 |
2001年 | 16篇 |
2000年 | 10篇 |
1999年 | 26篇 |
1998年 | 41篇 |
1997年 | 23篇 |
1996年 | 27篇 |
1995年 | 8篇 |
1994年 | 9篇 |
1993年 | 15篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1977年 | 9篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1966年 | 2篇 |
1957年 | 1篇 |
排序方式: 共有1132条查询结果,搜索用时 15 毫秒
51.
52.
Chiara Cipollina Andreina Bruno Salvatore Fasola Marta Cristaldi Bernardo Patella Rosalinda Inguanta Antonio Vilasi Giuseppe Aiello Stefania La Grutta Claudia Torino Elisabetta Pace 《International journal of molecular sciences》2022,23(3)
Exposure of the airways epithelium to environmental insults, including cigarette smoke, results in increased oxidative stress due to unbalance between oxidants and antioxidants in favor of oxidants. Oxidative stress is a feature of inflammation and promotes the progression of chronic lung diseases, including Chronic Obstructive Pulmonary Disease (COPD). Increased oxidative stress leads to exhaustion of antioxidant defenses, alterations in autophagy/mitophagy and cell survival regulatory mechanisms, thus promoting cell senescence. All these events are amplified by the increase of inflammation driven by oxidative stress. Several models of bronchial epithelial cells are used to study the molecular mechanisms and the cellular functions altered by cigarette smoke extract (CSE) exposure, and to test the efficacy of molecules with antioxidant properties. This review offers a comprehensive synthesis of human in-vitro and ex-vivo studies published from 2011 to 2021 describing the molecular and cellular mechanisms evoked by CSE exposure in bronchial epithelial cells, the most used experimental models and the mechanisms of action of cellular antioxidants systems as well as natural and synthetic antioxidant compounds. 相似文献
53.
Francesca Antonucci Federico Pallottino Graziella Paglia Amedeo Palma Salvatore D��Aquino Paolo Menesatti 《Food and Bioprocess Technology》2011,4(5):809-813
Sugar content is one of the most important quality attributes of citrus fruit, either for fresh or for processing market.
Since sugars in citrus juice are highly correlated with total soluble solids (TSS) content, which can be determined easily
even by the means of a hand refractometer, TSS is one of the most frequently used quality index. Since TSS can be measured
only destructively, the results are representative only if carried out on large samples and do not allow classifying marketable
fruit one by one according to their specific sugar content. Objective of this experiment was to assess possibility and limits
of a non-destructive estimation of citrus fruits internal quality parameters (TSS and titratable acidity) presenting thick
peel by the use of a spectrophotometric portable VIS-NIR system. Four hundred fruit of “Miho” satsuma and 150 fruit of “Page”
tangelo were used. Each fruit was first subjected to spectrophotometric acquisition and soon after was juiced and TSS and
titratable acidity (TA) determined. Partial least squares (PLS) regression analysis was applied for constructing a predictive
model based on the spectral normalized response, constructing the model on a sub-sample and verifying the model (prediction
test) on independent ones. The TA relative to Page mandarin was predicted in the test with an r = 0.88 and a standard error of prevision (SEP) coefficient of variability of 3.8% while the TSS scored an r = 0.85 and a SEP coefficient of variability equal to 4%. The TA of Miho mandarin was predicted in the test with an r = 0.81 and a SEP coefficient of Variability of 8.3% while the TSS scored an r = 0.84 and a SEP coefficient of variability equal to 5.6%. 相似文献
54.
We studied changes in lipid composition of human promyelocytic leukemia cells (HL-60) on differentiation to the macrophage/monocytic
lineage by treatment with the phorbol ester, 12-O-tetradecanoyl-phorbol-13-acetate. Differentiation was accompanied by: (i)
a decrease in the level of phospholipids; (ii) a greater amount of triacylglycerols; (iii) an increase in 1-alk-1′-enyl-2-acyl-
and 1-alkyl-2-acyl-sn-glycero-3-phosphoethanolamine and a decrease in 1-alkyl-2-acyl-sn-glycero-3-phosphocholine; and (iv) an increase in the level of arachidonic acid in ethanolamine phospholipids. The increased
levels of ether-linked lipids and of arachidonic acid in ethanolamine phospholipids are consistent with an enhanced biosynthesis
of platelet-activating factor and eicosanoids, which are particularly important in the macrophage function. 相似文献
55.
56.
Qian Wang Chunfeng Hu Shu Cai Yoshio Sakka Salvatore Grasso Qing Huang 《International Journal of Applied Ceramic Technology》2014,11(5):911-918
High‐purity ternary laminated compound Ti3SiC2 was successfully synthesized by a microwave heating method in the flowing argon for the first time. The mixtures of titanium, silicon, and graphitic carbon (Cgc) or activated carbon (Cac) with different molar ratios were used to investigate the reaction mechanisms. It was confirmed that Ti3SiC2 with high purity of 98 vol.% was achieved without the aids of Al. The optimum experimental parameters were determined as Ti/Si/Cgc having the molar ratio of 3/2.2/2, first holding at 1480°C for 30 min, and subsequent dwelling at 1300°C for 60 min. 相似文献
57.
Lubomír Pospíšil Magdaléna Hromadová Jana Bulí?ková Salvatore Filippone Zhu Guan Yongmin Zhang 《Carbon》2010,48(1):153-1408
The formal redox potentials of electron transfer reactions of fullerene, methanofullerene, fullerene-cyclodextrin complex and methanofullerene conjugates with cyclodextrins in aqueous and dimethylsulfoxide solutions are reported. These new compounds are surface active and retain the redox activity of C60 even in aqueous medium. Compounds have been characterized by an electrochemical admittance technique, which offers an advantage of separating faradaic and capacitive properties. Observed difference of formal redox potentials of the free fullerene forms and their cyclodextrin-containing compounds were used to determine the binding enhancement. Results are interpreted in terms of inter-molecular host-guest interactions of C60-cyclodextrin conjugates. 相似文献
58.
59.
Chiara Maria Motta Emanuela Califano Rosaria Scudiero Bice Avallone Chiara Fogliano Salvatore De Bonis Anja Raggio Palma Simoniello 《International journal of molecular sciences》2022,23(4)
In aquatic organisms, cadmium exposure occurs from ovum to death and the route of absorption is particularly wide, being represented by skin, gills and gastrointestinal tract, through which contaminated water and/or preys are ingested. It is known that cadmium interferes with the gut; however, less information is available on cadmium effects on an important component of the gut, namely goblet cells, specialized in mucus synthesis. In the present work, we studied the effects of two sublethal cadmium concentrations on the gut mucosa of Danio rerio. Particular attention was paid to changes in the distribution of glycan residues, and in metallothionein expression in intestinal cells. The results show that cadmium interferes with gut mucosa and goblet cells features. The effects are dose- and site-dependent, the anterior gut being more markedly affected than the midgut. Cadmium modifies the presence and/or distribution of glycans in the brush border and cytoplasm of enterocytes and in the goblet cells’ cytoplasm and alters the metallothionein expression and localization. The results suggest a significant interference of cadmium with mucosal efficiency, representing a health risk for the organism in direct contact with contamination and indirectly for the trophic chain. 相似文献
60.
Maria Lisa Garavaglia Daniela Giustarini Graziano Colombo Francesco Reggiani Silvia Finazzi Marta Calatroni Lucia Landoni Nicola Marcello Portinaro Aldo Milzani Salvatore Badalamenti Ranieri Rossi Isabella Dalle-Donne 《International journal of molecular sciences》2022,23(5)
Thiols (sulfhydryl groups) are effective antioxidants that can preserve the correct structure of proteins, and can protect cells and tissues from damage induced by oxidative stress. Abnormal levels of thiols have been measured in the blood of patients with moderate-to-severe chronic kidney disease (CKD) compared to healthy subjects, as well as in end-stage renal disease (ESRD) patients on haemodialysis or peritoneal dialysis. The levels of protein thiols (a measure of the endogenous antioxidant capacity inversely related to protein oxidation) and S-thiolated proteins (mixed disulphides of protein thiols and low molecular mass thiols), and the protein thiolation index (the molar ratio of the S-thiolated proteins to free protein thiols in plasma) have been investigated in the plasma or red blood cells of CKD and ESRD patients as possible biomarkers of oxidative stress. This type of minimally invasive analysis provides valuable information on the redox status of the less-easily accessible tissues and organs, and of the whole organism. This review provides an overview of reversible modifications in protein thiols in the setting of CKD and renal replacement therapy. The evidence suggests that protein thiols, S-thiolated proteins, and the protein thiolation index are promising biomarkers of reversible oxidative stress that could be included in the routine monitoring of CKD and ESRD patients. 相似文献