全文获取类型
收费全文 | 1421篇 |
免费 | 51篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 25篇 |
综合类 | 1篇 |
化学工业 | 409篇 |
金属工艺 | 16篇 |
机械仪表 | 25篇 |
建筑科学 | 33篇 |
矿业工程 | 7篇 |
能源动力 | 22篇 |
轻工业 | 67篇 |
水利工程 | 10篇 |
石油天然气 | 1篇 |
武器工业 | 1篇 |
无线电 | 105篇 |
一般工业技术 | 252篇 |
冶金工业 | 238篇 |
原子能技术 | 11篇 |
自动化技术 | 253篇 |
出版年
2023年 | 11篇 |
2022年 | 38篇 |
2021年 | 29篇 |
2020年 | 17篇 |
2019年 | 18篇 |
2018年 | 23篇 |
2017年 | 24篇 |
2016年 | 26篇 |
2015年 | 19篇 |
2014年 | 34篇 |
2013年 | 100篇 |
2012年 | 61篇 |
2011年 | 70篇 |
2010年 | 46篇 |
2009年 | 50篇 |
2008年 | 33篇 |
2007年 | 30篇 |
2006年 | 55篇 |
2005年 | 47篇 |
2004年 | 51篇 |
2003年 | 49篇 |
2002年 | 35篇 |
2001年 | 17篇 |
2000年 | 22篇 |
1999年 | 16篇 |
1998年 | 18篇 |
1997年 | 20篇 |
1996年 | 24篇 |
1995年 | 16篇 |
1994年 | 20篇 |
1993年 | 16篇 |
1992年 | 24篇 |
1991年 | 11篇 |
1990年 | 14篇 |
1989年 | 19篇 |
1988年 | 20篇 |
1987年 | 12篇 |
1986年 | 17篇 |
1985年 | 15篇 |
1982年 | 19篇 |
1981年 | 13篇 |
1980年 | 14篇 |
1979年 | 16篇 |
1978年 | 23篇 |
1977年 | 16篇 |
1976年 | 25篇 |
1975年 | 16篇 |
1974年 | 21篇 |
1973年 | 14篇 |
1970年 | 10篇 |
排序方式: 共有1476条查询结果,搜索用时 31 毫秒
101.
Administered relational size problems in the context of ordinal series to 72 4-5 yr olds. Solution was facilitated when Ss were directed to locate a terminal member (the smallest) of the series. In contrast, Ss who were instructed to locate a nonterminal member without prior designation of a terminal member were unable to achieve solution of the problem. Age- and sex-related differences in performance were observed as well as differences associated with stimulus arrangements and stimulus sizes. The outcomes are discussed in terms of composite task demands. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
102.
In clinical trials it may be necessary to convert a commercial tablet to a capsule so that the identity of each drug being tested remains unknown until the trial is completed. This study shows that for six commercial tablets, after pulverization and encapsulation of the powder, the in vitro dissolution was faster for one product, slower for two products and essentially unchanged for three products. 相似文献
103.
104.
105.
A statistical model for identifying proteins by tandem mass spectrometry 总被引:51,自引:0,他引:51
A statistical model is presented for computing probabilities that proteins are present in a sample on the basis of peptides assigned to tandem mass (MS/MS) spectra acquired from a proteolytic digest of the sample. Peptides that correspond to more than a single protein in the sequence database are apportioned among all corresponding proteins, and a minimal protein list sufficient to account for the observed peptide assignments is derived using the expectation-maximization algorithm. Using peptide assignments to spectra generated from a sample of 18 purified proteins, as well as complex H. influenzae and Halobacterium samples, the model is shown to produce probabilities that are accurate and have high power to discriminate correct from incorrect protein identifications. This method allows filtering of large-scale proteomics data sets with predictable sensitivity and false positive identification error rates. Fast, consistent, and transparent, it provides a standard for publishing large-scale protein identification data sets in the literature and for comparing the results obtained from different experiments. 相似文献
106.
107.
108.
Eugene A Smirnov Maria A Meledina Alexey V Garshev Vitaly I Chelpanov Sven Frost Jan U Wieneke Mathias Ulbricht 《Polymer International》2013,62(5):836-841
Titania microspheres with narrow size distribution and diameters of about 1 µm were prepared and subsequently functionalized using surface‐initiated atom transfer radical polymerization (ATRP) of N‐isopropylacrylamide. The ATRP initiator was immobilized on the particle surface via acylation of surface hydroxyl groups with α‐bromoisobutyryl bromide. Subsequently, an established ATRP reaction system was used for the preparation of titania surface‐grafted poly(N‐isopropylacrylamide) (PNiPAAm). Characterization was performed with electron microscopies, X‐ray diffraction, infrared spectroscopy and dynamic light scattering. It was found that the particle size in aqueous dispersions changed reversibly with temperature as expected for a shell of PNiPAAm, a polymer with a lower critical solution temperature at 32 °C. This confirmed the successful preparation of functional, stimuli‐responsive TiO2 microparticles via a straightforward controlled surface‐initiated polymerization method. 相似文献
109.
In this experimental study a practical geometrical comparison between inclined (angle φ) free and repelled hydraulic jumps (the latter in non prismatic but abruptly expanding channels) is presented, analysed and
discussed. For repelled hydraulic jumps a considerable parameter is the expansion ratio r (=channels’ width ratio), which here is changing from r =0.5 to r =0.7. The comparison is made with the free jump (in prismatic channel, r =1), in the same ranges of angles φ (0° ⩽ φ ⩽8°) and Froude numbers (2⩽Fr
1⩽8). A practical arithmetic example is presented to show the behavioral change of conjugate depths, lengths L and depths at 0.5L, in order to receive a comparison among all pertinent geometrical quantities. The present results may be useful for the hydraulic
engineering when designing open channels. 相似文献
110.