全文获取类型
收费全文 | 1047篇 |
免费 | 26篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 354篇 |
金属工艺 | 67篇 |
机械仪表 | 43篇 |
建筑科学 | 58篇 |
矿业工程 | 1篇 |
能源动力 | 35篇 |
轻工业 | 123篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
武器工业 | 1篇 |
无线电 | 48篇 |
一般工业技术 | 172篇 |
冶金工业 | 46篇 |
原子能技术 | 12篇 |
自动化技术 | 107篇 |
出版年
2022年 | 21篇 |
2021年 | 43篇 |
2020年 | 13篇 |
2019年 | 12篇 |
2018年 | 25篇 |
2017年 | 18篇 |
2016年 | 35篇 |
2015年 | 25篇 |
2014年 | 28篇 |
2013年 | 60篇 |
2012年 | 36篇 |
2011年 | 53篇 |
2010年 | 51篇 |
2009年 | 62篇 |
2008年 | 61篇 |
2007年 | 43篇 |
2006年 | 42篇 |
2005年 | 44篇 |
2004年 | 43篇 |
2003年 | 21篇 |
2002年 | 23篇 |
2001年 | 16篇 |
2000年 | 10篇 |
1999年 | 17篇 |
1998年 | 10篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1995年 | 13篇 |
1994年 | 14篇 |
1993年 | 16篇 |
1992年 | 11篇 |
1991年 | 7篇 |
1990年 | 10篇 |
1989年 | 9篇 |
1988年 | 16篇 |
1987年 | 13篇 |
1986年 | 19篇 |
1985年 | 15篇 |
1984年 | 17篇 |
1983年 | 11篇 |
1982年 | 7篇 |
1981年 | 11篇 |
1980年 | 9篇 |
1979年 | 12篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 6篇 |
1975年 | 9篇 |
1966年 | 2篇 |
1964年 | 3篇 |
排序方式: 共有1078条查询结果,搜索用时 15 毫秒
51.
α-Amylolysis of native potato and corn starches - SEM, AFM, nitrogen and iodine sorption investigations 总被引:1,自引:0,他引:1
Scanning electron microscopy (SEM), atomic force microscopy (AFM), as well as iodine and nitrogen sorption measurements were applied to investigate potato and corn starch granules surface after an action of Bacillus subtilis α-amylase. The SEM images revealed holes and pits (corn starch) or scratches (potato starch) on the surface of modified granules. These results were confirmed by AFM investigation which showed the presence of depressions of approximately 121 nm in diameter. Structure of the surface was not uniform. It consisted of small particles, amylopectin blocklets, of approximately 20 nm in diameter. They became more distinctive after α-amylolysis. Values of iodine binding capacity (IBC) obtained for hydrolyzed granules were lower than for native ones which indicated that the amylose and amylopectin chains building their surface were shortened. Specific surface area, volume and average diameter of mesopores increased for both starches after α-amylolysis. 相似文献
52.
Stroboscopic determination of settling velocity, size and porosity of activated sludge flocs 总被引:1,自引:0,他引:1
A multi-exposure photographic method was developed for the combined measurement of the settling velocity and size of activated sludge flocs. The proposed method mainly differs from the previous stroboscopic tests by introducing a new experimental arrangement which ensures sharp images of flocs on photographs.The relationships between individual floc-settling velocity and the floc size were found to be linear or fractional power functions. All these relationships were well correlated.Based on a simplified floc structure assumption and results of experimental measurements of floc-settling velocity and size, the floc porosity was determined. The porosity increased at two distinct rates as the floc size increased. 相似文献
53.
Natalia Cullell Cristina Gallego-Fbrega Jara Crcel-Mrquez Elena Muio Laia Lluci-Carol Miquel Lleds Jesús M. Martín-Campos Jessica Molina Laura Casas Marta Almeria Israel Fernndez-Cadenas Jerzy Krupinski 《International journal of molecular sciences》2022,23(6)
Small vessel strokes (SVS) and intracerebral haemorrhages (ICH) are acute outcomes of cerebral small vessel disease (SVD). Genetic studies combining both phenotypes have identified three loci associated with both traits. However, the genetic cis-regulation at the protein level associated with SVD has not been studied before. We performed a proteome-wide association study (PWAS) using FUSION to integrate a genome-wide association study (GWAS) and brain proteomic data to discover the common mechanisms regulating both SVS and ICH. Dorsolateral prefrontal cortex (dPFC) brain proteomes from the ROS/MAP study (N = 376 subjects and 1443 proteins) and the summary statistics for the SVS GWAS from the MEGASTROKE study (N = 237,511) and multi-trait analysis of GWAS (MTAG)-ICH–SVS from Chung et al. (N = 240,269) were selected. We performed PWAS and then a co-localization analysis with COLOC. The significant and nominal results were validated using a replication dPFC proteome (N = 152). The replicated results (q-value < 0.05) were further investigated for the causality relationship using summary data-based Mendelian randomization (SMR). One protein (ICA1L) was significantly associated with SVS (z-score = −4.42 and p-value = 9.6 × 10−6) and non-lobar ICH (z-score = −4.8 and p-value = 1.58 × 10−6) in the discovery PWAS, with a high co-localization posterior probability of 4. In the validation PWAS, ICA1L remained significantly associated with both traits. The SMR results for ICA1L indicated a causal association of protein expression levels in the brain with SVS (p-value = 3.66 × 10−5) and non-lobar ICH (p-value = 1.81 × 10−5). Our results show that the association of ICA1L with SVS and non-lobar ICH is conditioned by the cis-regulation of its protein levels in the brain. 相似文献
54.
Magdalena Zielińska-Dawidziak Dorota Piasecka-Kwiatkowska Jerzy R. Warchalewski Agnieszka Makowska Magdalena Gawlak Jan Nawrot 《European Food Research and Technology》2014,238(5):829-835
Grains of winter wheat (Korweta variety) were partially germinated in an abiotic stress condition (0–15 mM FeSO4 solutions) in order to accumulate iron by ferritin overexpression. The physical, chemical, biochemical properties and technological parameters of the obtained material as well as their resistance to an insect storage pest—granary weevil—were analyzed. Sprouted wheat grains with overexpression of ferritin contain 52 times more iron, more than 50 % in form of ferritin. The contents of reducing sugars, crude protein, fiber and ash as well as amylolytic activity increased significantly in sprouted wheat grain, while starch, fat, wet gluten, falling number and inhibition activity against granary weevil α-amylase decreased. Germinated wheat grain enriched with iron strongly affected granary weevil developmental parameters. Despite the fact that technological parameters of the product were deteriorated, it is worth to consider this material application as an iron supplement for cereal products, when the application of soybean is impossible. 相似文献
55.
Since the publication of Loftus and Masson’s (1994) method for computing confidence intervals (CIs) in repeated-measures (RM) designs, there has been uncertainty about how to apply it to particular effects in complex factorial designs. Masson and Loftus (2003) proposed that RM CIs for factorial designs be based on number of observations rather than number of participants. However, determining the correct number of observations for a particular effect can be complicated, given the variety of effects occurring in factorial designs. In this paper the authors define a general “number of observations” principle, explain why it obtains, and provide step-by-step instructions for constructing CIs for various effect types. The authors illustrate these procedures with numerical examples. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
56.
57.
58.
The basic and commonly used four types of thin-layer facade plasters on cement and silicate binders were subjected to 400 cycles of accelerated ageing in the simulate chamber. The main attention was focused on the character of pore structure evolution during of ageing process. To reach this objective, examinations of the microstructure by the mercury intrusion method and total porosity by the densitometry method were carried out in time per 100 cycles. During the study, the main emphasis was put on the open porosity and changes of dimensional groups of pores. On the ground of the hysteresis of the mercury pressure by mercury intrusion porosimetry testing, the presence of pores with capillary entrance was suggested. In view of this, the cylindrical and spherical model of porous structure has been defined. The contribution of capillary and spherical pores vary in time together with properties such as: average pore radius, length of cylindrical pores and their tortuosity. The changes of these values confirm that atmospherical ageing influences plasters’ binders in two zones. It appears on the one hand by the decrease of total porosity, length and diameter of capillaries but on the other hand by the increase of open porosity and the decrease of pores’ tortuosity. It indicates the tightening character of the inside pore structure of the examined plasters and at the same time it gives diverse effect in its external zone. 相似文献
59.
Synthesis of Ternary Titanium Aluminum Carbides Using Self-Propagating High-Temperature Synthesis Technique 总被引:6,自引:0,他引:6
Micha opaciski Jan Puszynski Jerzy Lis 《Journal of the American Ceramic Society》2001,84(12):3051-3053
Different ternary carbide phases, namely Ti3 AlC2 , Ti3 AlC, and Ti2 AlC, were successfully synthesized in a self-sustaining regime. Direct reactions among elemental powders of titanium, aluminum, and carbon are strongly exothermic, and the resulting reaction products consist of binary carbides and they are partially molten. The use of TiAl, instead of elemental titanium and aluminum, significantly reduces the combustion temperature. As a result, ternary titanium aluminum carbide phases are formed. In addition, the combustion-synthesized products are not sintered and easy to deagglomerate. Reaction conditions and X-ray diffraction patterns of different ternary phases formed in a self-sustaining regime are presented. 相似文献
60.
A domain-of-influence theorem for an initial-boundary-value problem of thermoelasticity with one relaxation time, proposed by Lord and Schulman, is established. The theorem asserts that for a finite time t > 0 a pair (<φ, ), in which φ and are the thermoelastic potential and temperature, respectively, generates no thermoelastic disturbances outside a bounded domain Dt. 相似文献