全文获取类型
收费全文 | 1420篇 |
免费 | 134篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 13篇 |
综合类 | 1篇 |
化学工业 | 323篇 |
金属工艺 | 23篇 |
机械仪表 | 81篇 |
建筑科学 | 47篇 |
矿业工程 | 6篇 |
能源动力 | 44篇 |
轻工业 | 409篇 |
水利工程 | 13篇 |
石油天然气 | 4篇 |
无线电 | 63篇 |
一般工业技术 | 208篇 |
冶金工业 | 21篇 |
原子能技术 | 4篇 |
自动化技术 | 295篇 |
出版年
2024年 | 10篇 |
2023年 | 17篇 |
2022年 | 38篇 |
2021年 | 93篇 |
2020年 | 61篇 |
2019年 | 71篇 |
2018年 | 94篇 |
2017年 | 86篇 |
2016年 | 83篇 |
2015年 | 76篇 |
2014年 | 79篇 |
2013年 | 228篇 |
2012年 | 115篇 |
2011年 | 116篇 |
2010年 | 111篇 |
2009年 | 79篇 |
2008年 | 47篇 |
2007年 | 25篇 |
2006年 | 20篇 |
2005年 | 9篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 14篇 |
2001年 | 6篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 14篇 |
1997年 | 7篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1965年 | 2篇 |
1964年 | 1篇 |
1963年 | 2篇 |
1938年 | 2篇 |
排序方式: 共有1555条查询结果,搜索用时 15 毫秒
61.
Gastón Gutiérrez-Gamboa Eva P. Pérez-Álvarez Pilar Rubio-Bretón Teresa Garde-Cerdán 《International Journal of Food Science & Technology》2019,54(4):1160-1168
Edible mushrooms production presents a potential problem for the environment, due to the large amount of waste generated. These wastes contain nitrogenous matter, which could be used as biostimulant in plants. The aim of this work was to study the effect of waste waters, from the mushroom production process, applied at veraison and 1 week later to grapevine leaves, on grape volatile compounds over two vintages. The results evidenced that mushroom water treatment decreased the grape content of certain terpenoids, C13 norisoprenoids, benzenoid compounds and esters, increasing C6 compounds content during the first season. Treated mushroom water application slightly affected grape volatile composition. This was the treatment that least affected the content of grape volatile composition. Few differences were found after the biostimulation during the second vintage. The season was the dominant factor of grape volatile content variation compared to the treatment and their interaction. 相似文献
62.
Water Resources Management - It is a challenge to develop models that can represent the stochastic behaviour of rivers and basins. Currently used streamflow models were constructed under rigid... 相似文献
63.
Effects of UV exclusion on the physiology and phenolic composition of leaves and berries of Vitis vinifera cv. Graciano 下载免费PDF全文
64.
Post‐harvest control of gray mold in table grapes using volatile sulfur compounds from Allium sativum 下载免费PDF全文
65.
Characterization of phenolic composition in Carignan noir grapes (Vitis vinifera L.) from six wine‐growing sites in Maule Valley,Chile 下载免费PDF全文
66.
67.
Inline electron holography and VEELS for the measurement of strain in ternary and quaternary (In,Al,Ga)N alloyed thin films and its effect on bandgap energy 下载免费PDF全文
J.M. MÁNUEL C.T. KOCH V.B. ÖZDÖL W. SIGLE P.A. VAN AKEN R. GARCÍA F.M. MORALES 《Journal of microscopy》2016,261(1):27-35
We present the use of (1) dark‐field inline electron holography for measuring the structural strain, and indirectly obtaining the composition, in a wurtzite, 4‐nm‐thick InAlGaN epilayer on a AlN/GaN/AlN/GaN multinano‐layer heterosystem, and (2) valence electron energy‐loss spectroscopy to study the bandgap value of five different, also hexagonal, 20–50‐nm‐thick InAlGaN layers. The measured strain values were almost identical to the ones obtained by other techniques for similarly grown materials. We found that the biaxial strain in the III‐N alloys lowers the bandgap energy as compared to the value calculated with different known expressions and bowing parameters for unstrained layers. By contrast, calculated and experimental values agreed in the case of lattice‐matched (almost unstrained) heterostructures. 相似文献
68.
MIRIAM S. GRENÓN JOSÉ ROBLEDO JUAN CARLOS IBÁÑEZ HÉCTOR J. SÁNCHEZ 《Journal of microscopy》2016,264(2):182-188
Dental implants are composed of commercially pure Ti (which is actually an alloy of titanium, and minor or trace components such as aluminium and vanadium). When the implant is inserted, its surface undergoes a number of chemical and mechanical processes, releasing particles of titanium to the medium. The metabolism of free ions of titanium is uncertain; the uptaking processes in the body are not well known, nor their toxic dose. In addition, physical properties of newly formed bone, such as diffusivity and activation energy, are scarce and rarely studied. In this study, we analysed the diffusion of titanium in the titanium‐implanted shinbones of six adult male Wistar rats by spatially resolved micro x‐ray fluorescence. The measurements were carried out at the microfluorescence station of the x‐ray fluorescence (XRF) beamline of the Brazilian synchrotron facility LNLS (from Portuguese ‘Laboratorio Nacional de Luz Sincrotron’). For each sample, XRF spectra were taken by linear scanning in area near the new bone formed around the Ti implant. The scanning line shows a clear effect of titanium diffusion whereas calcium intensity presents a different behaviour. Moreover, a clear correlation among the different structures of bones is observed in the Ti and Ca intensities. The results obtained in these measurements may allow determining quantitatively the parameters of diffusion rates and other physical properties of new bone like diffusion coefficients. 相似文献
69.
We report image blurring and energy broadening effects in energy-filtered XPEEM when illuminating the specimen with soft X-rays at high flux densities. With a flux of 2×1013 photons/s, the lateral resolution in XPEEM imaging with either core level or secondary electrons is degraded to more than 50 nm. Fermi level broadening up to several hundred meV and spectral shift to higher kinetic energies are also systematically observed. Simple considerations suggest that these artifacts result from Boersch and Loeffler effects, and that the electron-electron interactions are strongest in the initial part of the microscope optical path. Implications for aberration corrected instruments are discussed. 相似文献
70.
Empar Llorca Isabel Hernando Isabel Pérez-Munuera Amparo Quiles Virginia Larrea M. Ángeles Lluch 《European Food Research and Technology》2007,225(5-6):807-813
The objective of this paper was to study the main chemical and microstructural changes in squid proteins during processing
as a frozen batter-coated product using different coatings. Protein bands of the squid and of the batters used for coating
were studied using SDS-PAGE. It is concluded that it is not only the proteins of the layer of batter, which are directly exposed
both to the frying oil and to freezing temperatures, that deteriorate during the preparation process, the protein fraction
of the squid substrate, mainly the myofibrillar proteins, is also degraded. At a microstructural level, big voids are generated
during freezing as a consequence of the packing of the fibres, although the size of these voids decreases after final frying.
After this step of the process, the central sarcoplasm is still visible but has been altered by coagulation of the sarcoplasmic
proteins and the sarcolemma is observed to be separate from the myofibrillar package. 相似文献