全文获取类型
收费全文 | 1922篇 |
免费 | 93篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 28篇 |
综合类 | 3篇 |
化学工业 | 466篇 |
金属工艺 | 25篇 |
机械仪表 | 25篇 |
建筑科学 | 97篇 |
能源动力 | 35篇 |
轻工业 | 235篇 |
水利工程 | 19篇 |
石油天然气 | 2篇 |
无线电 | 151篇 |
一般工业技术 | 300篇 |
冶金工业 | 405篇 |
原子能技术 | 20篇 |
自动化技术 | 207篇 |
出版年
2024年 | 5篇 |
2023年 | 28篇 |
2022年 | 71篇 |
2021年 | 89篇 |
2020年 | 53篇 |
2019年 | 35篇 |
2018年 | 48篇 |
2017年 | 38篇 |
2016年 | 52篇 |
2015年 | 52篇 |
2014年 | 49篇 |
2013年 | 111篇 |
2012年 | 113篇 |
2011年 | 117篇 |
2010年 | 82篇 |
2009年 | 94篇 |
2008年 | 118篇 |
2007年 | 85篇 |
2006年 | 71篇 |
2005年 | 53篇 |
2004年 | 55篇 |
2003年 | 50篇 |
2002年 | 34篇 |
2001年 | 35篇 |
2000年 | 18篇 |
1999年 | 39篇 |
1998年 | 64篇 |
1997年 | 43篇 |
1996年 | 49篇 |
1995年 | 24篇 |
1994年 | 29篇 |
1993年 | 21篇 |
1992年 | 14篇 |
1991年 | 12篇 |
1990年 | 11篇 |
1989年 | 14篇 |
1988年 | 9篇 |
1987年 | 16篇 |
1986年 | 10篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1982年 | 10篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1977年 | 4篇 |
1976年 | 15篇 |
1975年 | 4篇 |
1974年 | 5篇 |
1973年 | 4篇 |
1946年 | 4篇 |
排序方式: 共有2018条查询结果,搜索用时 15 毫秒
101.
102.
Judit Olh Tibor Sznsi Attila Lehotzky Victor Norris Judit Ovdi 《International journal of molecular sciences》2022,23(3)
Protein–protein interactions (PPIs) outnumber proteins and are crucial to many fundamental processes; in consequence, PPIs are associated with several pathological conditions including neurodegeneration and modulating them by drugs constitutes a potentially major class of therapy. Classically, however, the discovery of small molecules for use as drugs entails targeting individual proteins rather than targeting PPIs. This is largely because discovering small molecules to modulate PPIs has been seen as extremely challenging. Here, we review the difficulties and limitations of strategies to discover drugs that target PPIs directly or indirectly, taking as examples the disordered proteins involved in neurodegenerative diseases. 相似文献
103.
Amalia Ruiz-Serrano Christina N. Boyle Josep M. Monn Rodríguez Julia Günter Agnieszka E. Jucht Svende Pfundstein Andreas M. Bapst Thomas A. Lutz Roland H. Wenger Carsten C. Scholz 《International journal of molecular sciences》2022,23(3)
Dysregulated energy metabolism is a major contributor to a multitude of pathologies, including obesity and diabetes. Understanding the regulation of metabolic homeostasis is of utmost importance for the identification of therapeutic targets for the treatment of metabolically driven diseases. We previously identified the deubiquitinase OTUB1 as substrate for the cellular oxygen sensor factor-inhibiting HIF (FIH) with regulatory effects on cellular energy metabolism, but the physiological relevance of OTUB1 is unclear. Here, we report that the induced global deletion of OTUB1 in adult mice (Otub1 iKO) elevated energy expenditure, reduced age-dependent body weight gain, facilitated blood glucose clearance and lowered basal plasma insulin levels. The respiratory exchange ratio was maintained, indicating an unaltered nutrient oxidation. In addition, Otub1 deletion in cells enhanced AKT activity, leading to a larger cell size, higher ATP levels and reduced AMPK phosphorylation. AKT is an integral part of insulin-mediated signaling and Otub1 iKO mice presented with increased AKT phosphorylation following acute insulin administration combined with insulin hypersensitivity. We conclude that OTUB1 is an important regulator of metabolic homeostasis. 相似文献
104.
Christina Siakati Alexios P. Douvalis Panagiotis Ziogas Arne Peys Yiannis Pontikes 《Journal of the American Ceramic Society》2020,103(3):2173-2184
Aiming to reduce the carbon dioxide emissions associated with cement production, alternative binders such as inorganic polymers currently receive substantial attention and slags from the non-ferrous metallurgy are promising precursors. However, studies that correlate their chemistry and crystallinity with the newly formed binder remain limited. In this work, the effect of three different solidification methods on glass formation and reactivity of FeOx–SiO2 slags, as well as on the molecular structure of the resultant Fe-rich inorganic polymers, was investigated. The inorganic polymers were synthesized by mixing the slags (approximate molar ratio FeO/SiO2 = 1.6) with an alkali silicate solution (molar ratios SiO2/Na2O = 1.6 and H2O/Na2O = 25). Results demonstrated that higher cooling rates promoted higher glass formation and faster reaction kinetics when the slags were activated. 57Fe Mössbauer spectroscopy indicated that all the slags consisted predominantly of Fe2+ ions with a minor amount of Fe3+ ions, regardless of the variability in glass content. The binder phase of all inorganic polymers consisted of iron in both Fe2+ and Fe3+ states, after 28 days of curing. After pulverizing the inorganic polymer pastes and exposing the powder to air for 28 additional days, the Fe2+ state in the binder transformed to Fe3+. The compressive strength evolution of the three slags showed that the 2-day strength was higher for the samples with a higher amorphous fraction, while after 28 days, this influence was less pronounced. 相似文献
105.
Chitosan-based fiber-sponge materials as a promising tool for microalgae harvesting from Lake Baikal
Timofei E. Grigoriev Ksenia I. Lukanina Pavel M. Gotovtsev Kirill V. Gorin Anna A. Melnikova Christina G. Antipova Roman Kamyshinsky Sergei N. Chvalun 《应用聚合物科学杂志》2020,137(40):49209
Mass eutrophication of microalgae and cyanobacteria is observed in Lake Baikal in the past decade. In this paper, the concept of replaceable adsorption filter material based on chitosan flocculant filler and chlorinated polyvinyl chloride polymer nonwoven material are proposed. Functional and mechanical properties and morphology of the material are investigated depending on a packing density and a degree of chitosan filling. The introduction of 45% chitosan increases the Young's modulus up to 10 times, and it makes the material more rigid in 2.8 times. The high efficiency of sorption and growth inhibition of cumulative biomass culture was shown. The biomass source is taken from the coast of Barguzinsky Bay of Lake Baikal. Dominant species is microalgae of Scenedesmus genus. 相似文献
106.
Jake E. Doiron Dr. Christina A. Le Dr. John Bacsa Prof. Gary W. Breton Prof. Kenneth L. Martin Prof. Stephen G. Aller Prof. Mark Turlington 《ChemMedChem》2020,15(18):1720-1730
Although the 1,2,3-triazole is a commonly used amide bioisostere in medicinal chemistry, the structural implications of this replacement have not been fully studied. Employing X-ray crystallography and computational studies, we report the spatial and electronic consequences of replacing an amide with the triazole in analogues of cystic fibrosis drugs in the VX-770 and VX-809 series. Crystallographic analyses quantify subtle differences in the relative positions and conformational preferences of the R1 and R2 substituents attached to the amide and triazole bioisosteres. Computational studies derived from the X-ray data highlight the improved hydrogen bonding donor and acceptor capabilities of the amide in comparison to the triazole. This analysis of the spatial and electronic differences between the amide and 1,2,3-triazole will inform medicinal chemists as they consider using the triazole as an amide bioisostere. 相似文献
107.
Adib-Conquy Minou; Gilbert Michele; Christodoulou Christina; Avrameas Stratis 《Protein engineering, design & selection : PEDS》1995,8(9):859-863
In this report, we describe the expression system that enabledus to produce in Escherichia coli the Fab fragment of a mouseIgM that has previously been shown to inhibit the binding ofIgG to autoantigens by interacting with their variable regions.In our system, both light chain and heavy chain fragments wereput under the control of the malE promoter. The light chainwas fused to the MalE signal sequence, while the heavy chainvariable and first constant region were fused to the alkalinephosphatase signal sequence. In this system, after inductionof the promoter with maltose, the Fab fragment could be detectedin a periplasmic extract of the bacteria by Western blottingand also by ELISA. This Fab fragment was purified on a goatanti-mouse immunoglobulin immunoadsorbent and biotinylated.The Fab fragment produced by E.coli reacted with the trinitrophenyl(TNP) hapten and F(ab')2 fragments of mouse IgG and these reactivitiescould be specifically inhibited by the corresponding solubleantigens. The dissociation constants of this Fab were 1.65 x106 M for TNP and 5 x 106 M for IgG F(ab')2 fragments,indicating that the affinity of the Fab fragment compared withthat of the whole IgM molecule was similar for TNP but was lowerfor IgG F(ab')2 fragments 相似文献
108.
Greg Crescenzi Morgan Norris 《生命科学仪器》2007,5(6):43-45
目前,人们对食品饮料的分析检验的要求越来越严格.随着分析灵敏度的提高,人们对食品饮料分析中用水的质量提出了更高的要求.许多实验室仍然采用蒸馏的方法来生产纯水,但是采用能够提供更高水质的反渗透和电去离子系统更经济. 相似文献
109.
Characklis GW Dilts MJ Simmons OD Likirdopulos CA Krometis LA Sobsey MD 《Water research》2005,39(9):1773-1782
The degree to which microbes in the water column associate with settleable particles has important implications for microbial transport in receiving waters, as well as for microbial removal via sedimentation (i.e. detention basins). The partitioning behavior of several bacterial, protozoan and viral indicator organisms is explored in three urban streams under both storm and dry weather conditions. The fraction of organisms associated with settleable particles in stormwater is estimated through use of a centrifugation technique which is calibrated using suspensions of standard particles (e.g., glass, latex). The fraction of organisms associated with settleable particles varies by type of microbe, and the partitioning behavior of each organism generally changes between dry weather and storm conditions. Bacterial indicator organisms (fecal coliforms, Escherichia coli, enterococci) exhibited relatively consistent behavior, with an average of 20-35% of organisms associated with these particles in background samples and 30-55% in storm samples. Clostridium perfringens spores exhibited the highest average level of particle association, with storm values varying from 50% to 70%. Results related to total coliphage partitioning were more variable, with 20-60% associated with particles during storms. These estimates should be valuable in surface water quality modeling efforts, many of which currently assume that all microbes exist as free (unattached) organisms. 相似文献
110.
Rosiah Rohani Tetsuya Yamaki Hiroshi Koshikawa Shin Hasegawa Yasunari Maekawa Christina Trautmann 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(3):554-557
We investigated how pretreatment and high-LET beam irradiation affected the ion-track dissolution rate in poly(vinylidene fluoride) (PVDF) films by SEM observations and conductometric analysis in order to develop the preparation methodology of nano-sized ion-track membranes. PVDF thin films irradiated with four types of ion beams were exposed to a 9 mol/dm3 KOH aqueous solution after their storage in air at 120 °C. This heating treatment was found to enhance the etch rate in the latent track, both in the inner core and outer halo regions, without changing that in the bulk, probably due to the formation of parasitic oxidation products facilitating the introduction of the etching agent to improve the etchability. Additionally, the irradiation of heavier higher-LET ions, causing each track to more activated sites (like radicals), was preferable for achieving effective etching. 相似文献