全文获取类型
收费全文 | 161篇 |
免费 | 2篇 |
专业分类
化学 | 133篇 |
力学 | 6篇 |
数学 | 3篇 |
物理学 | 21篇 |
出版年
2022年 | 2篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2017年 | 2篇 |
2013年 | 8篇 |
2012年 | 6篇 |
2011年 | 5篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 4篇 |
2007年 | 5篇 |
2006年 | 4篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 2篇 |
1992年 | 3篇 |
1987年 | 2篇 |
1971年 | 2篇 |
1970年 | 6篇 |
1967年 | 5篇 |
1959年 | 2篇 |
1956年 | 2篇 |
1954年 | 2篇 |
1953年 | 2篇 |
1943年 | 2篇 |
1917年 | 2篇 |
1914年 | 2篇 |
1913年 | 4篇 |
1912年 | 10篇 |
1911年 | 1篇 |
1909年 | 1篇 |
1908年 | 2篇 |
1907年 | 2篇 |
1904年 | 1篇 |
1903年 | 3篇 |
1902年 | 3篇 |
1900年 | 1篇 |
1898年 | 1篇 |
1895年 | 1篇 |
1893年 | 2篇 |
1891年 | 2篇 |
1887年 | 1篇 |
1886年 | 3篇 |
1885年 | 1篇 |
1883年 | 1篇 |
1881年 | 1篇 |
1879年 | 5篇 |
1865年 | 1篇 |
1862年 | 3篇 |
排序方式: 共有163条查询结果,搜索用时 15 毫秒
81.
Iva Matolínová Viktor Johánek Josef Mysliveček Kevin C. Prince Tomáš Skála Michal Škoda Nataliya Tsud Mykhailo Vorokhta Vladimír Matolín 《Surface and interface analysis : SIA》2011,43(10):1325-1331
Methanol adsorption on ion‐sputtered Pt(111) surface exhibiting high concentration of vacancy islands and on (2 × 1)Pt(110) single crystal were investigated by means of photoelectron spectroscopy (PES) and thermal desorption spectroscopy. The measurements showed that methanol adsorbed at low temperature on sputtered Pt(111) and on (2 × 1)Pt(110) surfaces decomposed upon heating. The PES data of methanol adsorption were compared to the data of CO adsorbed on the same Pt single crystal surfaces. In the case of the sputtered Pt(111) surface, the dehydrogenation of HxCO intermediates is followed by the CO bond breakage. On the (2 × 1)Pt(110) surface, carbon monoxide, as product of methanol decomposition, desorbed molecularly without appearance of any traces of atomic carbon. By comparing both platinum surfaces we conclude that methanol decomposition occurs at higher temperature on sputtered Pt(111) than on (2 × 1)Pt(110). Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
82.
G. S. Wang Jae-Won Lee J. Y. Zhu Thomas W. Jeffries 《Applied biochemistry and biotechnology》2011,163(5):658-668
Aqueous dilute acid pretreatments of corncob were conducted using cylindrical pressure vessels in an oil bath. Pretreatments
were conducted in a temperature range of 160–190 °C with acid-solution-to-solid-corncob ratio of 2. The acid concentration
(v/v) in the pretreatment solution was varied from 0% to 0.7%, depending on temperature. This gives acid charge on ovendry-weight
corncob of 0–2.58%. It was found that optimal pretreatment temperature is between 160 and 170 °C based on total xylose and
glucose yields and thermal energy consumption in pretreatment. At 170 °C and acid charge of 2.2% on cob, total glucose yield
and xylose recovery were 97% and 75%, respectively, which resulted in an overall monomeric sugar recovery of about 88%. Xylose
concentration in the hydrolysate was about 12%, with xylose-to-acetic-acid ratio of 8 and to furan (furfural and hydroxymethylfurfural)
of about 15. 相似文献
83.
Fumihiko Kitagawa Kana Tanigawa‐Joh Satomi Terashita Ryohei Fujiki Isoshi Nukatsuka Kenji Sueyoshi Koji Otsuka 《Electrophoresis》2019,40(18-19):2478-2483
In this study, we found that the polarity switching was effective to enrich and separate fluorescent analytes which have weakly‐dissociated groups in a floating platinum electrode (width, 50 µm; thickness, 2.5 µm)‐integrated straight‐channel in microchip electrophoresis (MCE). In the straight channel filled with an Alexa Flour 488 (AF488) solution, a sharp peak was observed after the polarity inversion with a 530‐fold enhancement of the sensitivity relative to the conventional MCE analysis. By using a fluorescent pH indicator, we verified that a sharp high‐pH zone was generated nearby the floating electrode and moved toward the anode with maintaining the high pH, which induced the sample enrichment like a dynamic pH junction mechanism. In the floating electrode‐embedded channel, the mixture of AF488‐labeled proteins was also well concentrated and separated within 100 s. 相似文献
84.
85.
86.
87.
Joh -Ludw v. Eichborn 《Colloid and polymer science》1956,147(3):156-160
Ohne Zusammenfassung 相似文献
88.
A metal-matrix specimen was investigated using moiré interferometry with 2400 ℓ/mm (60,960 ℓ/in.). The specimen was a 6-ply
[0/±45]
s
boron-aluminum tensile coupon with a central slot. The unequal deformations in fibers and matrix were evident. Special attention
was given to a plastic slip zone in the matrix. Normal and shear strains were calculated in the slip zone; the shear-strain
concentration factor rose dramatically with the onset of plastic slip and continued to rise gradually with load to 95 percent
of the failure load. The precipitous change from maximum tensile strain in one fiber to zero tensile strain in the neighboring
fiber was accommodated by the very high shear strain in the matrix in the slip zone. Experimental considerations are discussed:
shear strains are independent of rigid-body rotations; simplified strain calculations are justified; averaging across the
narrow slip region and the influence of finite thickness of the specimen grating contribute to underestimation of peak strains.
Paper was presented at the 1986 SEM Spring Conference on Experimental Mechanics held in New Orleans, LA on June 8–13. 相似文献
89.
Jae-Won Cho Hyo Sup Shim Chang Young Lee Seong Yong Park Min Hee Hong Insuk Lee Hye Ryun Kim 《Experimental & molecular medicine》2022,54(1):12
Lung squamous cell carcinoma (LUSC) is a subtype of non-small cell lung cancer (NSCLC). LUSC occurs at the bronchi, shows a squamous appearance, and often occurs in smokers. To determine the epigenetic regulatory mechanisms of tumorigenesis, we performed a genome-wide analysis of DNA methylation in tumor and adjacent normal tissues from LUSC patients. With the Infinium Methylation EPIC Array, > 850,000 CpG sites, including ~350,000 CpG sites for enhancer regions, were profiled, and the differentially methylated regions (DMRs) overlapping promoters (pDMRs) and enhancers (eDMRs) between tumor and normal tissues were identified. Dimension reduction based on DMR profiles revealed that eDMRs alone and not pDMRs alone can differentiate tumors from normal tissues with the equivalent performance of total DMRs. We observed a stronger negative correlation of LUSC-specific gene expression with methylation for enhancers than promoters. Target genes of eDMRs rather than pDMRs were found to be enriched for tumor-associated genes and pathways. Furthermore, DMR methylation associated with immune infiltration was more frequently observed among enhancers than promoters. Our results suggest that methylation of enhancer regions rather than promoters play more important roles in epigenetic regulation of tumorigenesis and immune infiltration in LUSC.Subject terms: Cancer genomics, Non-small-cell lung cancer 相似文献
90.
Jae-Won Song Sunju Choi Gayeong Kim Hyang Bok Lee P. Sankara Rao Jeonghyun Shin Eun Ki Kim Dong-Gyu Cho 《Molecules (Basel, Switzerland)》2022,27(7)
A novel melanoblast stimulator (1) was isolated from Dimocarpus longan. Its analogs were also synthesized to support a new furan-based melanoblast stimulator scaffold for treating vitiligo. Isolated 5-(hydroxymethyl)furfural (HMF, 1) is a well-known compound in the food industry. Surprisingly, the melanogenic activity of HMF (1) was discovered here for the first time. Both HMF and its synthetic analog (16) promote the differentiation and migration of melanoblasts in vitro. Typically, stimulator (1) upregulated MMP2 expression, which promoted the migration of melanoblasts in vitro. 相似文献