全文获取类型
收费全文 | 6111篇 |
免费 | 487篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 58篇 |
综合类 | 9篇 |
化学工业 | 2555篇 |
金属工艺 | 77篇 |
机械仪表 | 86篇 |
建筑科学 | 263篇 |
矿业工程 | 35篇 |
能源动力 | 160篇 |
轻工业 | 1130篇 |
水利工程 | 41篇 |
石油天然气 | 35篇 |
无线电 | 258篇 |
一般工业技术 | 937篇 |
冶金工业 | 320篇 |
原子能技术 | 15篇 |
自动化技术 | 630篇 |
出版年
2024年 | 12篇 |
2023年 | 58篇 |
2022年 | 453篇 |
2021年 | 774篇 |
2020年 | 230篇 |
2019年 | 210篇 |
2018年 | 254篇 |
2017年 | 207篇 |
2016年 | 263篇 |
2015年 | 224篇 |
2014年 | 271篇 |
2013年 | 449篇 |
2012年 | 374篇 |
2011年 | 412篇 |
2010年 | 276篇 |
2009年 | 274篇 |
2008年 | 276篇 |
2007年 | 243篇 |
2006年 | 214篇 |
2005年 | 152篇 |
2004年 | 139篇 |
2003年 | 113篇 |
2002年 | 99篇 |
2001年 | 55篇 |
2000年 | 46篇 |
1999年 | 55篇 |
1998年 | 35篇 |
1997年 | 42篇 |
1996年 | 43篇 |
1995年 | 35篇 |
1994年 | 36篇 |
1993年 | 31篇 |
1992年 | 27篇 |
1991年 | 16篇 |
1990年 | 23篇 |
1989年 | 11篇 |
1988年 | 18篇 |
1987年 | 14篇 |
1986年 | 7篇 |
1985年 | 18篇 |
1984年 | 16篇 |
1983年 | 17篇 |
1982年 | 6篇 |
1981年 | 11篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1974年 | 4篇 |
1966年 | 5篇 |
排序方式: 共有6609条查询结果,搜索用时 15 毫秒
991.
Beln Surez Anna Picinelli Javier Moreno Juan J Mangas 《Journal of the science of food and agriculture》1998,78(4):461-465
An analytical procedure for the quantitative determination of the major polyphenols in apple juices which successfully employs a RP-HPLC system without prior treatment of the sample is described. Apple juices were clarified by microfiltration and ultrafiltration without previous treatment. Polyphenols monitored were influenced by clarification technology employed for stabilising the apple juices. The p-coumaric acid derivative was significantly affected by membrane type and filtration time, while (−)-epicatechin and phloridzin were influenced by filtration time. © 1998 Society of Chemical Industry. 相似文献
992.
Magdalena Laskowska Anna Nowak Mateusz Dulski Peter Weigl Thomas Blochowicz ukasz Laskowski 《International journal of molecular sciences》2021,22(24)
Photoluminescence is known to have huge potential for applications in studying biological systems. In that respect, phosphorescent dye molecules open the possibility to study the local slow solvent dynamics close to hard and soft surfaces and interfaces using the triplet state (TSD: triplet state solvation dynamics). However, for that purpose, probe molecules with efficient phosphorescence features are required with a fixed location on the surface. In this article, a potential TSD probe is presented in the form of a nanocomposite: we synthesize spherical silica particles with 2-naphthalene methanol molecules attached to the surface with a predefined surface density. The synthesis procedure is described in detail, and the obtained materials are characterized employing transmission electron microscopy imaging, Raman, and X-ray photoelectron spectroscopy. Finally, TSD experiments are carried out in order to confirm the phosphorescence properties of the obtained materials and the route to develop phosphorescent sensors at silica surfaces based on the presented results is discussed. 相似文献
993.
994.
Piotr Ciesielski Pawe J
wiak Ewa Forma Anna Krzelak 《International journal of molecular sciences》2021,22(24)
TET3 is a member of the TET (ten-eleven translocation) proteins family that catalyzes the conversion of the 5-methylcytosine into 5-hydroxymethylcytosine. TET proteins can also affect chromatin modifications and gene expression independently of their enzymatic activity via interactions with other proteins. O-GlcNAc transferase (OGT), the enzyme responsible for modification of proteins via binding of N-acetylglucosamine residues, is one of the proteins whose action may be dependent on TET3. Here, we demonstrated that in endometrial cancer cells both TET3 and OGT affected the expression of genes involved in epithelial to mesenchymal transition (EMT), i.e., FOXC1, TWIST1, and ZEB1. OGT overexpression was caused by an increase in TWIST1 and ZEB1 levels in HEC-1A and Ishikawa cells, which was associated with increased O-GlcNAcylation of histone H2B and trimethylation of H3K4. The TET3 had the opposite effect on gene expressions and histone modifications. OGT and TET3 differently affected FOXC1 expression and the migratory potential of HEC-1A and Ishikawa cells. Analysis of gene expressions in cancer tissue samples from endometrial cancer patients confirmed the association between OGT or TET3 and EMT genes. Our results contribute to the knowledge of the role of the TET3/OGT relationship in the complex mechanism supporting endometrial cancer progression. 相似文献
995.
Keunbin YIM Yeonkyu PARK Anna PARK Namhee CHO Chongmu LEE 《材料科学技术学报》2006,22(6):807-810
Pt/ZrO2/Si sandwich structures where ZrO2 is deposited by radio frequency (r.f.) magnetron sputtering using a Zr target in an atmosphere of O2/Ar gas mixture, were fabricated and the effects of the O2/Ar flow ratio in the reactive sputtering process, the annealing temperature, the ZrO2 film thickness on the structure, the surface roughness of ZrO2 films and the electric properties of Pt/ZrO2/Si metal-oxide-semiconductor (MOS) capacitors were investigated. The optimum process parameters of the Pt/ZrO2/Si capacitor based on reactively sputtered-ZrO2 determined in such a way as the capacitance is maximized and the leakage current, the oxide charge, and the interface trap density are minimized that is the O2/Ar flow ratio of 1.5, the annealing temperature of 800℃, and the film thickness of 10 nm. Also the conduction mechanism in the Pt/ZrO2/Si capacitor has been discussed. 相似文献
996.
997.
Jessica Da Gama Duarte Luke T. Quigley Anna Rachel Young Masaru Hayashi Mariko Miyazawa Alex Lopata Nunzio Mancuso Mikio Mikami Andreas Behren Els Meeusen 《International journal of molecular sciences》2021,22(20)
Ovarian cancers include several disease subtypes and patients often present with advanced metastatic disease and a poor prognosis. New biomarkers for early diagnosis and targeted therapy are, therefore, urgently required. This study uses antibodies produced locally in tumor-draining lymph nodes (ASC probes) of individual ovarian cancer patients to screen two separate protein microarray platforms and identify cognate tumor antigens. The resulting antigen profiles were unique for each individual cancer patient and were used to generate a 50-antigen custom microarray. Serum from a separate cohort of ovarian cancer patients encompassing four disease subtypes was screened on the custom array and we identified 28.8% of all ovarian cancers, with a higher sensitivity for mucinous (50.0%) and serous (40.0%) subtypes. Combining local and circulating antibodies with high-density protein microarrays can identify novel, patient-specific tumor-associated antigens that may have diagnostic, prognostic or therapeutic uses in ovarian cancer. 相似文献
998.
Although fatty acid composition is the most important attribute used to control oxidation stability, all edible oils are affected by lipid oxidation irrespective of whether they are highly unsaturated or not. The aim of the study was to compare the oxidation of rapeseed oil (RO) and butter oil (BO) triacylglycerols (TAGs) and their mixtures containing 10% or 20% of the other. Oxidation of the TAGs at 40°C was followed by formation of primary and secondary products. Statistical methods were used to interpret the data. The RO and BO TAGs and their mixtures began to oxidise without any induction periods. In the RO TAGs more hydroperoxides and p‐anisidine reactive compounds were formed than in the BO TAGs. The BO TAGs oxidised more than would be expected by their fatty acid composition. High susceptibility of BO TAGs to oxidation was caused by the easy breakdown of their hydroperoxides. Heptadienal and heptenal were specific products of oxidised RO TAGs and heptanal and nonenal of oxidised BO TAGs. Mixtures of RO and BO TAGs behaved according to which was dominant in the mixture. However, as little as 10% of RO or BO TAG introduced its specific oxidation products to the mixture. © 1999 Society of Chemical Industry 相似文献
999.
Jianguo Sun Hualin Ye Jin An Sam Oh Yao Sun Anna Plewa Yumei Wang Tian Wu Kaiyang Zeng Li Lu 《Nano Research》2022,(3):2123-2129
Generation of large strains upon Na+intercalation is one of the prime concerns of the mechanical degradation of Prussian blue(PB)and its analogs.Structural cons... 相似文献
1000.
Claudia Fecher-Trost Karin Wolske Christine Wesely Heidi Lhr Daniel S. Klawitter Petra Weissgerber Elise Gradhand Christine P. Burren Anna E. Mason Manuel Winter Ulrich Wissenbach 《International journal of molecular sciences》2021,22(23)
Recently, we reported a case of an infant with neonatal severe under-mineralizing skeletal dysplasia caused by mutations within both alleles of the TRPV6 gene. One mutation results in an in frame stop codon (R510stop) that leads to a truncated, nonfunctional TRPV6 channel, and the second in a point mutation (G660R) that, surprisingly, does not affect the Ca2+ permeability of TRPV6. We mimicked the subunit composition of the unaffected heterozygous parent and child by coexpressing the TRPV6 G660R and R510stop mutants and combinations with wild type TRPV6. We show that both the G660R and R510stop mutant subunits are expressed and result in decreased calcium uptake, which is the result of the reduced abundancy of functional TRPV6 channels within the plasma membrane. We compared the proteomic profiles of a healthy placenta with that of the diseased infant and detected, exclusively in the latter two proteases, HTRA1 and cathepsin G. Our results implicate that the combination of the two mutant TRPV6 subunits, which are expressed in the placenta of the diseased child, is responsible for the decreased calcium uptake, which could explain the skeletal dysplasia. In addition, placental calcium deficiency also appears to be associated with an increase in the expression of proteases. 相似文献