全文获取类型
收费全文 | 817篇 |
免费 | 42篇 |
专业分类
电工技术 | 14篇 |
综合类 | 6篇 |
化学工业 | 237篇 |
金属工艺 | 11篇 |
机械仪表 | 51篇 |
建筑科学 | 23篇 |
能源动力 | 34篇 |
轻工业 | 93篇 |
水利工程 | 5篇 |
石油天然气 | 1篇 |
无线电 | 37篇 |
一般工业技术 | 101篇 |
冶金工业 | 48篇 |
原子能技术 | 11篇 |
自动化技术 | 187篇 |
出版年
2024年 | 1篇 |
2023年 | 9篇 |
2022年 | 35篇 |
2021年 | 59篇 |
2020年 | 26篇 |
2019年 | 28篇 |
2018年 | 24篇 |
2017年 | 24篇 |
2016年 | 38篇 |
2015年 | 17篇 |
2014年 | 34篇 |
2013年 | 62篇 |
2012年 | 64篇 |
2011年 | 56篇 |
2010年 | 41篇 |
2009年 | 37篇 |
2008年 | 31篇 |
2007年 | 33篇 |
2006年 | 26篇 |
2005年 | 27篇 |
2004年 | 16篇 |
2003年 | 23篇 |
2002年 | 25篇 |
2001年 | 10篇 |
2000年 | 9篇 |
1999年 | 13篇 |
1998年 | 10篇 |
1997年 | 22篇 |
1996年 | 12篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有859条查询结果,搜索用时 31 毫秒
81.
E Scribano G Loria G Ascenti I Pandolfo A Blandino M Gaeta 《Canadian Metallurgical Quarterly》1995,89(5):658-661
The facial lymph nodes are classified in five groups: mandibular, buccinator, infraorbital, malar and retrozygomatic nodes. This paper reports the CT appearance of neoplastic involvement of these nodes, an unusual and not well documented event. The CT examinations of 62 patients with a history of primary or recurrent cancer of the epidermal structures of the face, oral cavity and sinonasal region were retrospectively reviewed to assess the presence of facial adenopathy. Nine cases of neoplastic involvement of facial nodes were found. Most commonly the buccinator nodes (4 cases) were involved, the infraorbital, mandibular (2 cases) and retrozygomatic nodes (1 case) being less commonly involved. No malar nodes were found. Neoplastic involvement of these nodes was caused by squamous cell carcinoma in 6 cases, by adenocarcinoma in 2 cases and by a lymphoma in 1 case. Normal nodes could not be confidently identified on CT studies. CT diagnosis of neoplastic involvement of facial nodes is based on the presence of a nodular lesion which lies along the lymphatic pathways of the primary neoplasm in an anatomically compatible location. CT diagnosis of facial nodes is very important for treatment planning if the nodes are deep or at a distance from primary cancer. This is especially true for retrozygomatic and buccinator nodes. 相似文献
82.
Massimiliano Ferronato Giuseppe Gambolati Pietro Teatini Domenico Baù 《Canadian Metallurgical Quarterly》2004,4(2):79-92
A numerical study is performed to simulate the vertical deformation of a depth interval representing a marker spacing (10.5 m) located in a deep heterogeneous sedimentary reservoir. Realistic lithostratigraphic sequences typical of the Northern Adriatic basin are used. A number of scenarios are addressed consistent with the available data. In particular two basic geologic scenarios at the marker scale are simulated, one where sands prevail within the marker spacing (SD), and another where thin sandy and clayey layers alternate (CL). The sensitivity of the marker response is investigated in relation to clay and sand permeability and compressibility contrast, Biot’s coefficient, and respective position of monitoring and fluid pumping wells. The modeling results show that rock may indeed expand above and below depleted layers. Depending on the marker position the expansion may partially offset the compaction, especially in the CL scenario with a very low permeable clay. To obtain a representative field compaction the markers should span a depth interval made mostly by sand and entirely depleted, and should be installed in a test hole far from producing wells. Compressibility contrast and the Biot coefficient play a secondary role. Very critical measurements are provided by two markers which incorporate a thin (≈1 m) depleted level overlain and underlain by almost impermeable clay layers. 相似文献
83.
84.
In this article, we propose an agent‐based approach for managing e‐commerce activities. In our approach, an agent is present in each e‐commerce site, managing the information stored there. In addition, another agent is associated with each customer, handling his/her profile. The proposed approach is based on the use of a particular conceptual model called the Behaviour‐Semantic Distance and Relevance (B‐SDR) network, which is capable of uniformly representing and handling information stored in e‐commerce sites and customer profiles. The capabilities of the B‐SDR network model are exploited to let customer and site agents cooperate in such a way in order to support a customer in identifying, whenever he/she accesses an e‐commerce site, those products and services present in the site itself and for better matching his/her interests. The approach has been implemented in a prototype in which its functionalities are discussed here also. © 2004 Wiley Periodicals, Inc. 相似文献
85.
86.
Domenico Sanfilippo 《Catalysis Today》1997,34(3-4):261-267
87.
Stefano Sivolella Giulia Brunello Nadia Ferrarese Alessandro Della Puppa Domenico D’Avella Eriberto Bressan Barbara Zavan 《International journal of molecular sciences》2014,15(2):3088-3117
Injury to peripheral nerves can occur as a result of various surgical procedures, including oral and maxillofacial surgery. In the case of nerve transaction, the gold standard treatment is the end-to-end reconnection of the two nerve stumps. When it cannot be performed, the actual strategies consist of the positioning of a nerve graft between the two stumps. Guided nerve regeneration using nano-structured scaffolds is a promising strategy to promote axon regeneration. Biodegradable electrospun conduits composed of aligned nanofibers is a new class of devices used to improve neurite extension and axon outgrowth. Self assembled peptide nanofibrous scaffolds (SAPNSs) demonstrated promising results in animal models for central nervous system injuries, and, more recently, for peripheral nerve injury. Aims of this work are (1) to review electrospun and self-assembled nanofibrous scaffolds use in vitro and in vivo for peripheral nerve regeneration; and (2) its application in peripheral nerve injuries treatment. The review focused on nanofibrous scaffolds with a diameter of less than approximately 250 nm. The conjugation in a nano scale of a natural bioactive factor with a resorbable synthetic or natural material may represent the best compromise providing both biological and mechanical cues for guided nerve regeneration. Injured peripheral nerves, such as trigeminal and facial, may benefit from these treatments. 相似文献
88.
Thermophiles as Potential Source of Novel Endotoxin Antagonists: the Full Structure and Bioactivity of theLipo‐oligosaccharide from Thermomonas hydrothermalis
下载免费PDF全文
![点击此处可从《Chembiochem : a European journal of chemical biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Flaviana Di Lorenzo Dr. Ida Paciello Dr. Luigi Lembo Fazio Dr. Luciana Albuquerque Dr. Luisa Sturiale Prof. Milton S. da Costa Prof. Rosa Lanzetta Prof. Michelangelo Parrilli Prof. Domenico Garozzo Prof. Maria Lina Bernardini Dott. Alba Silipo Prof. Antonio Molinaro 《Chembiochem : a European journal of chemical biology》2014,15(14):2146-2155
Thermomonas hydrothermalis is a Gram‐negative thermophilic bacterium that is able to live at 50 °C. This ability is attributed to chemical modifications, involving those to bacterial cell‐wall components, such as proteins and (glyco)lipids. As the main component of the outer membrane of Gram‐negative bacteria, lipopolysaccharides (LPSs) are exposed to the environment, thus they can undergo structural chemical changes to allow thermophilic bacteria to live at their optimal growth temperature. Furthermore, as one of the major target of the eukaryotic innate immune system, LPS elicits host immune response in a structure‐dependent mode; thus the uncommon chemical features of thermophilic bacterial LPSs might exert a different biological action on the innate immune system—an antagonistic effect, as shown in studies of LPS structure–activity relationship in the ongoing research into antagonist LPS candidates. Here, we report the complete structural and biological activity analysis of the lipo‐oligosaccharide isolated from Thermomonas hydrothermalis, achieved by a multidisciplinary approach (chemical analysis, NMR, MALDI MS and cellular immunology). We demonstrate a tricky and interesting structure combined with a very interesting effect on human innate immunity. 相似文献
89.
Manuela Lasagna Caterina Caviglia Domenico Antonio De Luca 《Bulletin of Engineering Geology and the Environment》2014,73(2):341-355
The Maggiore Valley well field plays a fundamental role in supplying drinking water to a large territory of the Piedmont (north-western Italy). However, an increasing demand for water has led to the overexploitation of the groundwater resources. This situation has caused a progressive drawdown of the piezometric level (locally, up to 0.8 m/year), a spatial reduction in the artesian zone, localised land subsidence and damage to wells. The main purpose of this study was the development of a groundwater flow model of the area for analysing the aquifer response to various pumping strategies. Initially, the groundwater flow simulation (achieved by the application of the MODFLOW code) was calibrated satisfactorily. Then, the groundwater response to four scenarios was simulated to explore the best option to mitigate the problem. In three of the scenarios, a withdrawal reduction of 110 l/s was simulated, whilst considering various relocation options for extraction within the well field. The fourth scenario simulated a withdrawal reduction of 150 l/s; this option also assumed a supplementary water supply from the Monferrato Aqueduct, located north of the study area. All the simulations provided an increase in the piezometric level; in some instances, up to 30 m. Based on these simulations, the most promising management strategy for the Maggiore Valley well field would seem to be the option using a supplementary feed from the Monferrato Aqueduct. In this instance, the predicted piezometric level rise would be up to 25 m; this option also precludes the need for drilling additional wells. 相似文献
90.
Brambilla G De Filippis SP Iamiceli AL Iacovella N Abate V Aronica V Di Marco V di Domenico A 《Journal of food protection》2011,74(2):261-269
An observational study was designed to assess the bioaccumulation of polychlorodibenzodioxins (PCDD) and polychlorodibenzofurans (PCDF), dioxin-like polychlorobiphenyls (DL-PCB), and 13 selected polybromodiphenylethers (PBDE) in autochthonous pigs reared in the Nebrodi Park of Sicily (Italy). Perirenal fat and liver samples were drawn from animals representative of three different outdoor farming systems and from wild pigs and then analyzed for the chemicals mentioned previously. The highest concentrations of PCDD + PCDF and DL-PCB were detected in the fat (0.45 and 0.35 pg World Health Organization toxicity equivalents [WHO-TE] per g of fat base [FB], respectively) and livers (12.7 and 3.28 pg WHO-TE per g FB) of the wild group, whereas the free-ranging group showed the lowest levels (0.05 and 0.03 pg WHO-TE per g FB in fat and 0.78 and 0.27 pg WHO-TE per g FB in livers). The sum of PBDE congeners was highest in wild pigs (0.52 ng/g FB in fat and 5.64 ng/g FB in livers) and lowest in the farmed group (0.14 ng/g FB in fat and 0.28 ng/g FB in livers). The contamination levels in fat and livers of outdoor pigs had mean concentration values lower than those levels reported for intensively indoor-farmed animals. In wild pigs, bioaccumulation was associated with their free grazing in areas characterized by bush fires. The results of this study aid to emphasize the quality of the environment as a factor to guarantee food safety in typical processed pig meat products, specifically from outdoor and extensive Nebrodi farming systems. 相似文献