全文获取类型
收费全文 | 1583篇 |
免费 | 65篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 57篇 |
综合类 | 4篇 |
化学工业 | 431篇 |
金属工艺 | 57篇 |
机械仪表 | 33篇 |
建筑科学 | 32篇 |
矿业工程 | 1篇 |
能源动力 | 65篇 |
轻工业 | 155篇 |
水利工程 | 7篇 |
石油天然气 | 1篇 |
无线电 | 129篇 |
一般工业技术 | 301篇 |
冶金工业 | 192篇 |
原子能技术 | 31篇 |
自动化技术 | 159篇 |
出版年
2023年 | 10篇 |
2022年 | 18篇 |
2021年 | 30篇 |
2020年 | 19篇 |
2019年 | 19篇 |
2018年 | 44篇 |
2017年 | 29篇 |
2016年 | 53篇 |
2015年 | 26篇 |
2014年 | 40篇 |
2013年 | 73篇 |
2012年 | 73篇 |
2011年 | 105篇 |
2010年 | 81篇 |
2009年 | 90篇 |
2008年 | 87篇 |
2007年 | 72篇 |
2006年 | 57篇 |
2005年 | 61篇 |
2004年 | 37篇 |
2003年 | 58篇 |
2002年 | 42篇 |
2001年 | 32篇 |
2000年 | 23篇 |
1999年 | 40篇 |
1998年 | 89篇 |
1997年 | 77篇 |
1996年 | 40篇 |
1995年 | 33篇 |
1994年 | 28篇 |
1993年 | 13篇 |
1992年 | 13篇 |
1991年 | 13篇 |
1990年 | 14篇 |
1989年 | 20篇 |
1988年 | 15篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1974年 | 3篇 |
1972年 | 3篇 |
1970年 | 3篇 |
1969年 | 4篇 |
1968年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有1655条查询结果,搜索用时 12 毫秒
991.
992.
Seita Osawa Hisashi Kato Yuki Maeda Hisashi Takakura Junetsu Ogasawara Tetsuya Izawa 《International journal of molecular sciences》2021,22(2)
Controlling the differentiation potential of adipose-derived stem cells (ADSCs) is attracting attention as a new strategy for the prevention and treatment of obesity. Here, we aimed to observe the effect of exercise training (TR) and high-fat diet (HFD) on the metabolic profiles of ADSCs-derived adipocytes. The rats were divided into four groups: normal diet (ND)-fed control (ND-SED), ND-fed TR (ND-TR), HFD-fed control (HFD-SED), and HFD-fed TR (HFD-TR). After 9 weeks of intervention, ADSCs of epididymal and inguinal adipose tissues were differentiated into adipocytes. In the metabolome analysis of adipocytes after isoproterenol stimulation, 116 metabolites were detected. The principal component analysis demonstrated that ADSCs-derived adipocytes segregated into four clusters in each fat pad. Amino acid accumulation was greater in epididymal ADSCs-derived adipocytes of ND-TR and HFD-TR, but lower in inguinal ADSCs-derived adipocytes of ND-TR, than in the respective controls. HFD accumulated several metabolites including amino acids in inguinal ADSCs-derived adipocytes and more other metabolites in epididymal ones. Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed that TR mainly affected the pathways related to amino acid metabolism, except in inguinal ADSCs-derived adipocytes of HFD-TR rats. These findings provide a new way to understand the mechanisms underlying possible changes in the differentiation of ADSCs due to TR or HFD. 相似文献
993.
Haoyu Huang Nozomu Sakurai Toshiyuki Takagi Tetsuya Uchimoto 《NDT & E International》2003,36(7):515-522
This paper describes an arrayed multi-coil probe, newly developed for the testing and crack sizing of steam generator tubes by eddy current testing (ECT). The testing speed, the high sensitivity to shallow cracks and the crack sizing are the present requirements in ECT. Because of the multi-coil arrangement, the arrayed probe has a high detection speed around the whole tube, without the need for rotation. It is realized from former studies that knowing the number of cracks, their directions, and their positions beforehand is of great help in crack sizing. Thus, not only the sensitivities but also the spatial resolutions are important. Numerical simulations are applied to help the design of the probe from the viewpoint of the crack sizing of steam generator tubes. Experiments show that the present probe provides both a high detectability and a remarkable capability of reconstructing the shallow cracks of a tube. 相似文献
994.
Noritaka Yusa Zhenmao Chen Kenzo Miya Tetsuya Uchimoto Toshiyuki Takagi 《NDT & E International》2003,36(7):449-459
An inversion algorithm for the reconstruction of cracks from eddy current signals is developed in this study and applied to the profile evaluation of natural stress corrosion cracks that were found in steam generator tubes of a nuclear power plant. A crack is modeled as an assembly of small regions having conductivities inside so that eddy currents that flow across the cracks are considered. The conductivity of each region, which is assumed to be a discrete value, is reconstructed by means of the algorithm. Since the algorithm is based upon a tabu search that usually requires a large number of evaluating solution candidates, simulations are carried out on a supercomputer with the use of parallel computation using up to 128 CPUs so as to reconstruct the crack profiles within a reasonable computational time. It is demonstrated that the algorithm can estimate the profiles of the natural cracks with sufficient accuracy. The simulations also show that the algorithm is highly compatible with parallel computation. Additional simulations using other models of natural cracks are performed. Reconstructed profiles of the natural cracks, as a notch with zero conductivity, are very different from the true profiles, even though the reconstructed signals agree well with the measured values. This reveals that it is necessary to take the internal conductivity into consideration when dealing with natural cracks. 相似文献
995.
Noritaka Yusa Hidetoshi Hashizume Tetsuya Uchimoto Toshiyuki Takagi Kunihiro Sato 《Journal of Nuclear Science and Technology》2013,50(1):127-132
This study evaluated the electromagnetic characteristics of austenitic stainless steel welds from the viewpoint of eddy current testing. Seven welded plate specimens, which were welded using JIS Z3221:2010 YS316L welding metals, were prepared. Two welding metals and several welding conditions were adopted to discuss the generality. The results of eddy current examination of the specimens using three different types of eddy current probes, that is, an absolute pancake probe, a differential plus-point probe, and a uniform eddy current probe, confirmed that the welds cause a large noise especially when the absolute pancake probe was used. The analysis of the signals through finite element simulations revealed that the magnetic property of the welds is not negligible from the viewpoint of eddy current testing. Complementary experiments were conducted using a vibrating sample magnetometer to validate the results. 相似文献
996.
Energetic efficiency is an important indicator of cardiac function in acute myocardial infarction. However, the relationship between cardiac energetic efficiency and infarct size is not perfectly elucidated. In this study, the relationship is analysed by means of simulation using a theoretical model of the guinea pig left ventricle. In simulation with varied ratios of infarct area, pressure–volume area (PVA), which is an index of total mechanical energy by ventricular contraction, and myocardial oxygen consumption (MVO2) are calculated for each infarct ratio. Then, change of PVA when MVO2 alters (PVA/MVO2) as a well‐known index of energy conversion efficiency is evaluated. In addition, PVA/VO2, which represents a ratio of PVA change to alteration of mean oxygen consumption of myocytes except for infarct myocytes, is introduced as an index for real energetic efficiency. In simulation results, PVA/MVO2 increases but PVA/VO2 decreases as infarct area expands, because with expansion of infarct area PVA decreases but VO2 remains almost unchanged because of larger shortening of myocytes. This implies that the enlargement of shortening of noninfarcted myocyte to compensate for depression of cardiac output is a potential cause of myocardial remodelling.Inspec keywords: blood vessels, cardiology, cellular biophysics, haemodynamics, muscle, oxygen, physiological modelsOther keywords: theoretical analysis, left ventricular energetic efficiency, acute infarct size, cardiac function, acute myocardial infarction, cardiac energetic efficiency, guinea pig left ventricle, pressure‐volume area, total mechanical energy, ventricular contraction, myocardial oxygen consumption, energy conversion efficiency, myocyte mean oxygen consumption, infarct myocytes, energetic efficiency index, noninfarcted myocyte shortening enlargement, cardiac output, myocardial remodellingInspec keywords: blood vessels, cardiology, cellular biophysics, haemodynamics, muscle, oxygen, physiological modelsOther keywords: theoretical analysis, left ventricular energetic efficiency, acute infarct size, cardiac function, acute myocardial infarction, cardiac energetic efficiency, guinea pig left ventricle, pressure‐volume area, total mechanical energy, ventricular contraction, myocardial oxygen consumption, energy conversion efficiency, myocyte mean oxygen consumption, infarct myocytes, energetic efficiency index, noninfarcted myocyte shortening enlargement, cardiac output, myocardial remodelling 相似文献
997.
S Nakamura Y Kondo K Matsubae K Nakajima T Tasaki T Nagasaka 《Environmental science & technology》2012,46(17):9266-9273
Metals can in theory be infinitely recycled in a closed-loop without any degradation in quality. In reality, however, open-loop recycling is more typical for metal scrap recovered from end-of-life (EoL) products because mixing of different metal species results in scrap quality that no longer matches the originals. Further losses occur when meeting the quality requirement of the target product requires dilution of the secondary material by adding high purity materials. Standard LCA usually does not address these losses. This paper presents a novel approach to quantifying quality- and dilution losses, by means of hybrid input-output analysis. We focus on the losses associated with the recycling of ferrous materials from end-of-life vehicle (ELV) due to the mixing of copper, a typical contaminant in steel recycling. Given the quality of scrap in terms of copper density, the model determines the ratio by which scrap needs to be diluted in an electric arc furnace (EAF), and the amount of demand for EAF steel including those quantities needed for dilution. Application to a high-resolution Japanese IO table supplemented with data on ferrous materials including different grades of scrap indicates that a nationwide avoidance of these losses could result in a significant reduction of CO(2) emissions. 相似文献
998.
Tetsuya Suzuta Makoto Toba Yohko Abe Yuji Yoshimura 《Journal of the American Oil Chemists' Society》2012,89(11):1981-1989
A heterogeneous catalyst, FeO x /SiO2, prepared by the pore-filling method, was found to be active in the transesterification of crude Jatropha oil with methanol. When the transesterification reaction was carried out with a reaction temperature of 220?°C, a catalyst amount of 15?wt%, a methanol/oil molar ratio of 218:1, and a reaction time of 3?h, the yield of fatty acid methyl esters (FAME) in the product exceeded 99.0?%, and met with EN standards for allowable contents of glycerine and mono-, di-, and tri-glycerides. The correlation between the FAME production activity and measured acidity of the FeO x /SiO2 catalysts showed that the transesterification reaction was promoted via the acidic function of these catalysts, which are less inhibited by coexisting free fatty acids in the feedstock triglycerides. 相似文献
999.
Tomohiko Kanaoka Kouichi Tamura Hiromichi Wakui Masato Ohsawa Kengo Azushima Kazushi Uneda Ryu Kobayashi Tetsuya Fujikawa Yuko Tsurumi-Ikeya Akinobu Maeda Mai Yanagi Yoshiyuki Toya Satoshi Umemura 《International journal of molecular sciences》2013,14(8):16866-16881
Ambulatory blood pressure (BP) and heart rate (HR) profile are proposed to be related to renal deterioration and cardiovascular complication in hypertension and chronic kidney disease (CKD). In this study, we examined the beneficial effects cilnidipine, a unique L/N-type calcium channel blocker (CCB), in addition to renin-angiotensin system inhibitors, on ambulatory BP and HR profile, as well as cardiorenal function in hypertensive CKD patients. Forty-five patients were randomly assigned to the cilnidipine replacement group (n = 21) or the control CCBs group (n = 24) during a 24-week active treatment period. Although clinical BP values were similar in the cilnidipine and control CCBs groups after the treatment period, the results of ambulatory BP monitoring showed that the 24-h and daytime systolic BP levels in the cilnidipine group were significantly lower compared with the control group after the study. Furthermore, the left ventricular mass index (LVMI) was significantly decreased in the cilnidipine group compared to the control group after the study (LVMI, 135.3 ± 26.4 versus 181.2 ± 88.4, p = 0.031), with a significant difference in the changes in the LVMI between the cilnidipine and control groups (change in LVMI, −12.4 ± 23.7 versus 26.2 ± 64.4, p = 0.007). These results indicate that cilnidipine is beneficial for the suppression of pathological cardiac remodeling, at least partly, via a superior improving effect on ambulatory BP profile compared with control CCBs in hypertensive CKD patients. 相似文献
1000.
Takaaki Taniguchi Kazuhiro Yamaguchi Ayako Shigeta Yuki Matsuda Shinya Hayami Tetsuya Shimizu Takeshi Matsui Teruo Yamazaki Asami Funatstu Yukihiro Makinose Nobuhiro Matsushita Michio Koinuma Yasumichi Matsumoto 《Advanced functional materials》2013,23(25):3140-3145
Molecularly‐thin nanosheets are ultimate two‐dimensional (2D) nanomaterials potentially giving unusual physical and chemical properties due to the strong 2D quantum and surface effects. Here, it is demonstrated that 1.5‐nm‐thick ZnO nanosheets exhibit greatly enhanced room‐temperature ferromagnetism. Saturation magnetization value of the nanosheets with intercalated dodecyl sulfate layers is approximately 100 times that of ZnO mesocrystals. Anion exchange with dodecyl phosphate layers strongly suppresses ferromagnetic ordering as a result of surface defect passivation while maintaining bulk‐like n‐type semiconducting properties, which reveals significance of interfacial states to engineer functional properties of nanosheet‐based hybrid materials. 相似文献