全文获取类型
收费全文 | 120250篇 |
免费 | 21027篇 |
国内免费 | 3865篇 |
专业分类
电工技术 | 5928篇 |
技术理论 | 5篇 |
综合类 | 5660篇 |
化学工业 | 30284篇 |
金属工艺 | 5073篇 |
机械仪表 | 6091篇 |
建筑科学 | 7968篇 |
矿业工程 | 1856篇 |
能源动力 | 3450篇 |
轻工业 | 12835篇 |
水利工程 | 1831篇 |
石油天然气 | 3938篇 |
武器工业 | 598篇 |
无线电 | 16948篇 |
一般工业技术 | 21579篇 |
冶金工业 | 4427篇 |
原子能技术 | 1113篇 |
自动化技术 | 15558篇 |
出版年
2024年 | 250篇 |
2023年 | 1238篇 |
2022年 | 2190篇 |
2021年 | 3575篇 |
2020年 | 3662篇 |
2019年 | 5020篇 |
2018年 | 5138篇 |
2017年 | 5713篇 |
2016年 | 6102篇 |
2015年 | 7005篇 |
2014年 | 7793篇 |
2013年 | 9873篇 |
2012年 | 8064篇 |
2011年 | 8348篇 |
2010年 | 7837篇 |
2009年 | 7389篇 |
2008年 | 6933篇 |
2007年 | 6416篇 |
2006年 | 6269篇 |
2005年 | 5312篇 |
2004年 | 4279篇 |
2003年 | 4032篇 |
2002年 | 4291篇 |
2001年 | 3549篇 |
2000年 | 3096篇 |
1999年 | 2387篇 |
1998年 | 1762篇 |
1997年 | 1425篇 |
1996年 | 1289篇 |
1995年 | 1062篇 |
1994年 | 903篇 |
1993年 | 660篇 |
1992年 | 524篇 |
1991年 | 396篇 |
1990年 | 291篇 |
1989年 | 229篇 |
1988年 | 217篇 |
1987年 | 130篇 |
1986年 | 110篇 |
1985年 | 66篇 |
1984年 | 63篇 |
1983年 | 36篇 |
1982年 | 51篇 |
1981年 | 34篇 |
1980年 | 28篇 |
1979年 | 27篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 19篇 |
1975年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
132.
基于四候煤矿3108回风顺槽过F3断层期间,顶板出现严重破碎、下沉现象,提出了俯斜台阶法施工工艺,并对断层破碎带顶板采取MF-2型化学材料注浆加固以及"钢筋锚索网+U29梯形棚"联合支护措施。支护效果检验结果表明,联合支护有效控制了断层破碎区顶板下沉、破碎现象,保证了巷道顶板稳定性。 相似文献
133.
Alfredo M. Gravagnuolo Eden Morales‐Narváez Charlene Regina Santos Matos Sara Longobardi Paola Giardina Arben Merkoçi 《Advanced functional materials》2015,25(38):6084-6092
Class I hydrophobin Vmh2, a peculiar surface active and versatile fungal protein, is known to self‐assemble into chemically stable amphiphilic films, to be able to change wettability of surfaces, and to strongly adsorb other proteins. Herein, a fast, highly homogeneous and efficient glass functionalization by spontaneous self‐assembling of Vmh2 at liquid–solid interfaces is achieved (in 2 min). The Vmh2‐coated glass slides are proven to immobilize not only proteins but also nanomaterials such as graphene oxide (GO) and quantum dots (QDs). As models, bovine serum albumin labeled with Alexa 555 fluorophore, anti‐immunoglobulin G antibodies, and cadmium telluride QDs are patterned in a microarray fashion in order to demonstrate functionality, reproducibility, and versatility of the proposed substrate. Additionally, a GO layer is effectively and homogeneously self‐assembled onto the studied functionalized surface. This approach offers a quick and simple alternative to immobilize nanomaterials and proteins, which is appealing for new bioanalytical and nanobioenabled applications. 相似文献
134.
135.
Mohammad Reza Gaeeni Morteza Sasani Ghamsari Abbas Majd Abadi Mohammad Hossein Majles Ara Wooje Han Hyung‐Ho Park 《Journal of the American Ceramic Society》2015,98(6):1818-1822
A facile sol–gel procedure has been developed for the synthesis of colloidal alumina nanocrystals. For the first time, optical characterization procedures were employed to study the quantum confinement effects in optical properties of the prepared Al2O3 sol. Accordingly, the hyperbolic band model was used to determine the optical band gap of colloidal alumina nanocrystals. X‐Ray diffraction pattern was used to study the crystallographic phase of the dried gel. Morphological characterization was performed using scanning electron microscopy (SEM). Inductively Coupled Plasma (ICP) emission spectroscopy was used to determination purity of the Al2O3 powder. High‐resolution TEM showed that the diameter of colloidal nanocrystals is about 10 nm. Photoluminescence spectroscopy demonstrated that quantum yields for colloidal nanocrystals are 68% with 300 nm excitation wavelength. The experimental observations confirm that highly stable alumina sol with strong UV emission was synthesized. The mentioned optical properties have not been reported before. 相似文献
136.
137.
Linlin Zhu Liyuan Zhang Xi Li Xiaoqi Jin Tiejun Shi 《Fullerenes, Nanotubes and Carbon Nanostructures》2020,28(7):551-560
AbstractGraphene oxide (GO) was functionalized by polyether amine (PEA) via two methods which were one-pot modification in acetone (GON) and two steps with the intermediate product of GOCO-Cl generated (GONS). There were more PEA successfully grafted onto GO for GONS than GON. The onset polymerization temperatures of the benzoxazine (Bz) composites decreased by the inclusion of 1?wt% of GO, GON or GONS. Thermal stability of the polybenzoxazine (PBz) composites was significantly improved indicated from the increase of weight loss temperature. T10, T20 and T50 values of the composites with GONS were higher than that of the others. Toughness of PBzs may be enhanced by the incorporation of nanofillers, and GONS had stronger interfacial interaction with PBz matrix than GON. 相似文献
138.
Seong‐Hee Kim 《Quality and Reliability Engineering International》2015,31(6):923-934
We present a distribution‐free tabular cumulative sum chart for monitoring the variability of an autocorrelated process. A quantity known as the asymptotic variance parameter is employed as a measure of the variability, and a distribution‐free tabular cumulative sum chart is applied to variance estimates calculated from batches of nonoverlapping samples. The proposed chart is applicable to a stationary process with a general marginal distribution and a general autocorrelation structure. It also determines control limits analytically without trial‐and‐error simulations. The performance of the proposed chart is tested on stationary processes with both normal and nonnormal marginals with various autocorrelation structures. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
139.
Xi Shen Li-Peng Cao Jian-Fa Zhao Wei-Peng Wang Qing-Qing Liu Yuan Yao Jun-Jie Li Chang-Zhi Gu Ming-Wei Chen Chang-Qing Jin Ri-Cheng Yu 《Journal of the American Ceramic Society》2019,102(11):6469-6474
We propose the question of the modulated structures of copper oxide is caused by the [CuO2] in-plane oxygen vacancy or apical oxygen vacancy. Sr2CuO3+δ single-crystal samples were prepared using high-temperature and high-pressure methods. The major phase of Sr2CuO3+δ (δ = 0.4) single-crystal system is found to be constituted by the 5 a modulated structure with the Fmmm space group, which originates from the [CuO2] in-plane oxygen vacancy appearing in octahedral Cu-O. Besides, the presence of the [CuO2] in-plane oxygen vacancy may obliterate the superconductivity of the system. Experimental results deduce that the oxygen vacancy may appear in the apical oxygen sites in high-temperature copper oxide superconductors. 相似文献
140.
Natural Computing - The fiber stretching process plays the key role in the process of fiber production and its effects is measured by the stretching ratio. The stretching ratio is determined by the... 相似文献