全文获取类型
收费全文 | 688篇 |
免费 | 64篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 389篇 |
金属工艺 | 5篇 |
机械仪表 | 11篇 |
建筑科学 | 24篇 |
能源动力 | 9篇 |
轻工业 | 137篇 |
无线电 | 24篇 |
一般工业技术 | 73篇 |
冶金工业 | 8篇 |
自动化技术 | 68篇 |
出版年
2024年 | 1篇 |
2023年 | 12篇 |
2022年 | 124篇 |
2021年 | 103篇 |
2020年 | 28篇 |
2019年 | 24篇 |
2018年 | 40篇 |
2017年 | 26篇 |
2016年 | 35篇 |
2015年 | 39篇 |
2014年 | 43篇 |
2013年 | 43篇 |
2012年 | 36篇 |
2011年 | 39篇 |
2010年 | 29篇 |
2009年 | 30篇 |
2008年 | 26篇 |
2007年 | 10篇 |
2006年 | 15篇 |
2005年 | 23篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1997年 | 2篇 |
1994年 | 1篇 |
排序方式: 共有752条查询结果,搜索用时 24 毫秒
101.
Francesco Demetrio Lofaro Barbara Cisterna Maria Assunta Lacavalla Federico Boschi Manuela Malatesta Daniela Quaglino Carlo Zancanaro Federica Boraldi 《International journal of molecular sciences》2021,22(19)
Aging is characterized by a progressive decline of skeletal muscle (SM) mass and strength which may lead to sarcopenia in older persons. To date, a limited number of studies have been performed in the old SM looking at the whole, complex network of the extracellular matrix (i.e., matrisome) and its aging-associated changes. In this study, skeletal muscle proteins were isolated from whole gastrocnemius muscles of adult (12 mo.) and old (24 mo.) mice using three sequential extractions, each one analyzed by liquid chromatography with tandem mass spectrometry. Muscle sections were investigated using fluorescence- and transmission electron microscopy. This study provided the first characterization of the matrisome in the old SM demonstrating several statistically significantly increased matrisome proteins in the old vs. adult SM. Several proteomic findings were confirmed and expanded by morphological data. The current findings shed new light on the mutually cooperative interplay between cells and the extracellular environment in the aging SM. These data open the door for a better understanding of the mechanisms modulating myocellular behavior in aging (e.g., by altering mechano-sensing stimuli as well as signaling pathways) and their contribution to age-dependent muscle dysfunction. 相似文献
102.
Francesca Biagioni Federica Mastroiacovo Paola Lenzi Stefano Puglisi-Allegra Carla L. Busceti Larisa Ryskalin Rosangela Ferese Domenico Bucci Alessandro Frati Ferdinando Nicoletti Francesco Fornai 《International journal of molecular sciences》2021,22(19)
The peri-infarct region, which surrounds the irreversible ischemic stroke area is named ischemic penumbra. This term emphasizes the borderline conditions for neurons placed within such a critical region. Area penumbra separates the ischemic core, where frank cell loss occurs, from the surrounding healthy brain tissue. Within such a brain region, nervous matter, and mostly neurons are impaired concerning metabolic conditions. The classic biochemical marker, which reliably marks area penumbra is the over-expression of the heat shock protein 70 (HSP70). However, other proteins related to cell clearing pathways are modified within area penumbra. Among these, autophagy proteins like LC3 increase in a way, which recapitulates Hsp70. In contrast, components, such as P20S, markedly decrease. Despite apparent discrepancies, the present study indicates remarkable overlapping between LC3 and P20S redistribution within area penumbra. In fact, the amount of both proteins is markedly reduced within vacuoles. Specifically, a massive loss of LC3 + P20S immuno-positive vacuoles (autophagoproteasomes) is reported here. This represents the most relevant sub-cellular alteration here described in cell clearing pathways within area penumbra. The functional significance of these findings remains to be determined and it will take a novel experimental stream to decipher the fine-tuning of such a phenomenon. 相似文献
103.
Krizia Sagini Sandra Buratta Federica Delo Roberto Maria Pellegrino Stefano Giovagnoli Lorena Urbanelli Carla Emiliani 《International journal of molecular sciences》2021,22(23)
Amiodarone is a cationic amphiphilic drug used as an antiarrhythmic agent. It induces phospholipidosis, i.e., the accumulation of phospholipids within organelles of the endosomal–lysosomal system. Extracellular vesicles (EVs) are membrane-enclosed structures released by any type of cell and retrieved in every fluid of the body. EVs have been initially identified as a system to dispose cell waste, but they are also considered to be an additional manner to transmit intercellular signals. To understand the role of EVs in drug-induced phospholipidosis, we investigated EVs release in amiodarone-treated HEK-293 cells engineered to produce fluorescently labelled EVs. We observed that amiodarone induces the release of a higher number of EVs, mostly of a large/medium size. EVs released upon amiodarone treatment do not display significant morphological changes or altered size distribution, but they show a dose-dependent increase in autophagy associated markers, indicating a higher release of EVs with an autophagosome-like phenotype. Large/medium EVs also show a higher content of phospholipids. Drugs inducing lysosomal impairment such as chloroquine and bafilomycin A1 similarly prompt a higher release of EVs enriched in autophagy markers. This result suggests a mechanism associated with amiodarone-induced lysosomal impairment more than a connection with the accumulation of specific undigested substrates. Moreover, the implementation of the lysosomal function by overexpressing TFEB, a master gene regulator of lysosomal biogenesis, prevents the amiodarone-induced release of EVs, suggesting that this could be a feasible target to attenuate drug-induced abnormalities. 相似文献
104.
Roberto Fabiani Raffaela Fuccelli Federica Pieravanti Angelo De Bartolomeo Guido Morozzi 《Molecular nutrition & food research》2009,53(7):887-896
Hydroxytyrosol [3,4‐dihydroxyphenylethanol (3,4‐DHPEA)], a phenolic compound found exclusively in olive oil, exerts growth‐suppressive and pro‐apoptotic effects on different cancer cells. Although some molecular mechanisms involved in the pro‐apoptotic activity of 3,4‐DHPEA have been proposed, the initial stress signals responsible of this phenomenon are not known. Our aim was to assess the involvement of reactive oxygen species as mediators of apoptosis induced by 3,4‐DHPEA on HL60 cells. Apoptosis was determined by analyzing the nuclear fragmentation by both fluorescence microscopy and flow cytometry. The externalization of phosphatidylserine was evidenced using an Annexin V‐FITC kit. The concentration of H2O2 in the culture medium was measured by the ferrous ion oxidation‐xylenol orange method. The pro‐apoptotic effect of 3,4‐DHPEA (100 μM) was prevented by N‐acetyl‐cysteine, ascorbate, and α‐tocopherol. Catalase suppressed the 3,4‐DHPEA‐induced apoptosis, while the Fe(II)‐chelating reagent o‐phenantroline showed no effect, suggesting the involvement of H2O2 but not of OH?. Indeed, 3,4‐DHPEA caused accumulation of H2O2 in the culture medium. Tyrosol (p‐hydroxyphenylethanol) and caffeic acid, compounds structurally similar to 3,4‐DHPEA but not able to generate H2O2, did not induce an appreciable apoptotic effect. This is the first study demonstrating that apoptosis induction by 3,4‐DHPEA is mediated by the extracellular production of H2O2. 相似文献
105.
Federica Maltese Cornelis Erkelens Frank van der Kooy Young Hae Choi Robert Verpoorte 《Food chemistry》2009
Recently advanced analytical technology has provided evidence of the existence of stereoisomers of many natural products. Particularly, flavanones which might have two different configurations at C-2 exist in many food additives, e.g., citrus fruits. In this study, the possible stereoisomers of flavanone glycosides were identified by NMR spectroscopy. Based on NMR spectra of common flavanone glycosides such as naringin, hesperidin, and neohesperidin, the two existing diastereomeric forms of the molecules could clearly be distinguished. The 1H NMR resonances of two diastereomers of each flavanone glycosides investigated in this study were fully assigned with the assistance of diverse 2D NMR spectroscopy methods. 相似文献
106.
The introduction of surface-enhanced Raman spectroscopy (SERS) in the field of cultural heritage has significantly improved the analysis of the organic dyes and their complexes that have been used as textile dyes and pigments in paintings and other polychrome works of art since antiquity. Over the last five years, a number of different procedures have been developed by various research groups. In this Article, we evaluate the effect of pretreating samples by exposing them to hydrofluoric acid (HF) vapor prior to SERS analysis, a step designed to hydrolyze the dye-metal complexes and increase analyte adsorption on the nanosized metallic support, thus enhancing the SERS signal. Materials studied include pure colorants, commercial lake pigments, and fibers from dyed textiles, as well as actual aged samples, such as microscopic fragments of lakes on paper and ancient pigments and glazes from several works of art, covering a wide range of time, from the second century B.C. to the early 20th century. In each case, SERS spectra obtained with or without HF hydrolysis were critically evaluated. The pretreatment with HF vapor resulted in faster analysis and increased sensitivity in most cases, with the exception of dyed silk fibers, where silk protein hydrolyzates were found to interfere with SERS analysis. As a final point, a two-step procedure including SERS on untreated and treated samples is proposed as a standard approach: by analyzing a sample first without hydrolysis, and then, following removal of the colloid, upon HF treatment, the best and most reliable results for a great number of dyes and substrates are assured. 相似文献
107.
Federica Franzoni Massimo Milani Luca Montorsi Valeri Golovitchev 《International Journal of Hydrogen Energy》2010
In this paper the combined production of hydrogen and power based on the aluminum combustion with water is investigated. Furthermore, a concept system is proposed that is potentially able to provide pressurized hydrogen and high temperature steam along with heat and work at the crankshaft. The system demonstrates high energy conversion efficiency, and it fully complies with environment sustainability requirements. 相似文献
108.
Fermented Nut‐Based Vegan Food: Characterization of a Home made Product and Scale‐Up to an Industrial Pilot‐Scale Production
下载免费PDF全文
![点击此处可从《Journal of food science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
109.
Influence of vineyard altitude on Glera grape ripening (Vitis vinifera L.): effects on aroma evolution and wine sensory profile
下载免费PDF全文
![点击此处可从《Journal of the science of food and agriculture》网站下载免费的PDF全文](/ch/ext_images/free.gif)
110.
Transferable Antibiotic Resistances in Marketed Edible Grasshoppers (Locusta migratoria migratorioides)
下载免费PDF全文
![点击此处可从《Journal of food science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Andrea Osimani Cristiana Garofalo Lucia Aquilanti Vesna Milanović Federica Cardinali Manuela Taccari Marina Pasquini Stefano Tavoletti Francesca Clementi 《Journal of food science》2017,82(5):1184-1192
Grasshoppers are the most commonly eaten insects by humans worldwide, as they are rich in proteins and micronutrients. This study aimed to assess the occurrence of transferable antibiotic resistance genes in commercialized edible grasshoppers. To this end, the prevalence of 12 selected genes [aac(6’)‐Ie aph(2″)‐Ia, blaZ, erm(A), erm(B), erm(C), mecA, tet(M), tet(O), tet(S), tet(K), vanA, vanB] coding for resistance to antibiotics conventionally used in clinical practice was determined. The majority of samples were positive for tet(M) (70.0%), tet(K) (83.3%) and blaZ (83.3%). A low percentage of samples were positive for erm(B) (16.7%), erm(C) (26.7%), and aac(6’)‐Ie aph(2″)‐Ia (13.3%), whereas no samples were positive for erm(A), vanA, vanB, tet(O), and mecA. Cluster analysis identified 4 main clusters, allowing a separation of samples on the basis of their country of origin. 相似文献