全文获取类型
收费全文 | 287篇 |
免费 | 9篇 |
专业分类
电工技术 | 5篇 |
综合类 | 1篇 |
化学工业 | 107篇 |
金属工艺 | 3篇 |
机械仪表 | 5篇 |
建筑科学 | 4篇 |
能源动力 | 6篇 |
轻工业 | 104篇 |
水利工程 | 1篇 |
无线电 | 8篇 |
一般工业技术 | 30篇 |
冶金工业 | 5篇 |
原子能技术 | 3篇 |
自动化技术 | 14篇 |
出版年
2023年 | 3篇 |
2022年 | 10篇 |
2021年 | 15篇 |
2020年 | 3篇 |
2019年 | 7篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 10篇 |
2015年 | 4篇 |
2014年 | 16篇 |
2013年 | 12篇 |
2012年 | 23篇 |
2011年 | 18篇 |
2010年 | 8篇 |
2009年 | 16篇 |
2008年 | 13篇 |
2007年 | 9篇 |
2006年 | 9篇 |
2005年 | 12篇 |
2004年 | 13篇 |
2003年 | 11篇 |
2002年 | 6篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 6篇 |
1976年 | 1篇 |
排序方式: 共有296条查询结果,搜索用时 15 毫秒
71.
Isolation and Identification of Antihypertensive Peptides from Antarctic Krill Tail Meat Hydrolysate 总被引:2,自引:0,他引:2
Akimasa Hatanaka Hiroko Miyahara Ken Ichi Suzuki Seizo Sato 《Journal of food science》2009,74(4):H116-H120
ABSTRACT: Antarctic krill ( Euphausia superba ) obtained from the huge biomass in Antarctic waters is an important food product in Japan. Antarctic krill peptide powder (AKPP) prepared from the tail meat by enzymatic hydrolysis significantly decreased the systolic blood pressure in spontaneously hypertensive rats by a single oral administration (1, 10, or 100 mg). Presumably, the effect of AKPP was through inhibition of the conversion of angiotensin, which mediates blood pressure elevation, from its inactive propeptide to the mature angiotensin. Two potent angiotensin I-converting enzyme (ACE) inhibitory peptides were isolated from AKPP by high-performance liquid chromatography (HPLC) and identified as Val-Trp (IC50 = 2.75 μg/mL; 12.9 μM) and Leu-Lys-Tyr (IC50 = 4.26 μg/mL; 10.1 μM). Val-Trp and Leu-Lys-Tyr comprised 0.025%± 0.0023% (w/w) and 0.018%± 0.0023% (w/w) of AKPP, respectively, as measured by electrospray ionization mass spectrometry (ESI-MS). The contributions of Val-Trp and Leu-Lys-Tyr to the ACE inhibitor activity of AKPP were 17.7%± 1.60% and 8.04%± 1.03%, respectively, suggesting that these 2 peptides constitute a substantial portion of the overall ACE inhibitor potential of AKPP. 相似文献
72.
Kunimasa K Ohta T Tani H Kato E Eguchi R Kaji K Ikeda K Mori H Mori M Tatefuji T Yamori Y 《Molecular nutrition & food research》2011,55(11):1730-1734
Angiogenesis is a promising target for cancer prevention and treatment. This study aimed to determine the antiangiogenic effects of melinjo (Gnetum gnemon L.) seed extract and its resveratrol derivative components, such as gnetin C (GC), gnetin L (GL), gnemonoside A (GMA), gnemonoside C (GMC), and gnemonoside D (GMD). An ethanol extract of melinjo seeds (EEMS) and the two gnetins markedly inhibited the proliferation and tube formation of human umbilical vein endothelial cells (HUVEC) stimulated with vascular endothelial growth factor and basic fibroblast growth factor. The inhibitory effects of GC and GL were much stronger than those of resveratrol. GMC and GMD inhibited only proliferation, whereas GMA had almost no effect on the two endothelial cell functions. The EEMS and GC also reduced the cell viability of tube-forming HUVEC, with accompanying ERK1/2 inactivation, and suppressed the migration of HUVEC. Furthermore, dietary intake of EEMS significantly inhibited tumor angiogenesis in a mouse dorsal air sac assay. In conclusion, we found that the EEMS and its resveratrol derivatives, particularly GC, suppress multiple angiogenesis-related endothelial cell functions and/or tumor angiogenesis, indicating that the melinjo seeds and the natural resveratrol derivatives may be useful for cancer prevention and treatment. 相似文献
73.
Morita M Shimamura H Ishida N Imamura K Sakiyama T Nakanishi K 《Journal of Bioscience and Bioengineering》2004,98(3):200-206
alpha-Glucosidase was produced using recombinant Aspergillus oryzae by membrane-surface liquid culture (MSLC), a method previously developed by the authors and the results compared with other methods, including shaking flask culture (SFC), agar-plate culture (APC), culture on urethane sponge supports (USC), and liquid surface culture (LSC) to determine possible reasons for the advantageous features of MSLC. When yeast extract was used as a nitrogen source, the amount of enzyme produced by MSLC was 5 or more times higher than those for SFC and LSC, but similar to that using APC. Enzyme production in USC was slightly lower than in MSLC and APC. Cell growth was similar irrespective of the cultivation method used. When NaNO3, a typical inorganic nitrogen source was used, enzyme production in all the cultures was lower than that using yeast extract. However, even using NaNO3, the amount of the enzyme produced by MSLC was 8 to 20 times higher than those by SFC, APC, USC, and LSC. Although cell growth using NaNO3 was similar to that for yeast extract in MSLC, it was markedly decreased in SFC, APC, and LSC. The reason for the difference in enzyme productivity for various cultivation methods using yeast extract and NaNO3 as a nitrogen source is discussed, on the basis of the experimental findings. The role of the oxygen transfer effect and gene expression levels in enzyme production were also examined. 相似文献
74.
Hiroko Ohuchi Akira Yamadera Takashi Nakamura 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2000,450(2-3):343-352
Several experiments were performed to investigate the effects of temperature on the fading of the commercial imaging plate, IP (BAS-UR). The fading characteristics were measured under controlled temperatures between 0°C and 60°C after irradiation with 238U alpha-ray and 60Co gamma-ray sources. Applying Arrhenius' equation to the experimental results, we calculated a universal functional equation that includes two variables: elapsed time (t) and temperature (K). The photo-stimulated luminescence (PSL) calculated by this equation showed good agreement with the results of our experimental ones between 0°C and 40°C. From this equation, the activation energies of the fading are estimated to be about 0.9 eV for both 238U alpha-ray and 60Co gamma-ray sources. 相似文献
75.
76.
77.
Cognition, Technology & Work - Vessel traffic service (VTS) is important to protect the safety of maritime traffic. Along with the expansion of monitoring area per VTS operator in Tokyo Bay,... 相似文献
78.
79.
Thiobarbituric acid reaction of aldehydes and oxidized lipids in glacial acetic acid 总被引:1,自引:0,他引:1
Thiobarbituric acid (TBA) reaction of several aldehydes and oxidized lipids in glacial acetic acid was performed. All the
samples were freely soluble in the solvent used. Saturated aldehydes produced a stable yellow pigment with an absorption maximum
at 455 nm, a red pigment derived from malonaldehyde at 532 nm, and an orange pigment due to dienals at 495 nm. The absorbance
maximum was 7–9 per μmol for saturated aldehydes, 27.5 per μmol for malonaldehyde and about 2 per μmol for dienals. Autoxidation
of unoxidized lipids increased progressively in glacial acetic acid. When the TBA test was performed under nitrogen, autoxidation
of unoxidized lipids was inhibited completely. While saturated aldehydes produced no yellow pigment under nitrogen, oxidized
lipids produced a considerable amount of stable yellow pigment. The value for absorbance at 455 nm as a function of autoxidation
time paralleled those of peroxide values. The absorbance of most oxidized lipids at 455 nm was higher than at 532 nm. Yellow
pigment formation in the TBA test under nitrogen could not be ascribed to free saturated aldehydes but rather to unspecified
closely related substances. The stable yellow pigment was found to be an excellent indicator of lipid oxidation. 相似文献
80.
Moe Nishimura Hiroyuki Fuchino Kaoru Takayanagi Hitomi Kawakami Hiroko Nakayama Nobuo Kawahara Yasuhito Shimada 《International journal of molecular sciences》2021,22(12)
(1) Background: Screening of medicinal herbs is one of the most powerful approaches to identifying novel therapeutic molecules against many human diseases. To avoid potential harmful effects during medicinal use, toxicity testing is necessary in the early stages of drug discovery. The objective of this study was to identify the cytotoxic mechanisms of jegosaponin A and B from Styrax japonica Siebold et al. Zuccarini; (2) Methods: We screened Japanese medicinal herb extracts using PC-3 prostate cancer cells and found that a methanol extract isolated from the unripe fruit of Styrax japonica Siebold et al. Zuccarini (SJSZ) had an inhibitory effect on cell viability. We further performed fractionation assays with PC-3 cells and identified the bioactive compounds using LC/MS and NMR analysis. We clarified the toxic mechanisms of these compounds using PC-3 cells and zebrafish embryos; (3) Results: We identified two active molecules, jegosaponin A and jegosaponin B, in the inhibitory fractions of the methanol extract. These jegosaponins are toxic to zebrafish embryos during the early developmental stage. Jegosaponin A and B showed strong haemolytic activity in sheep defibrinated blood (EC50 = 2.1 μM, and 20.2 μM, respectively) and increased the cell membrane permeability in PC-3 cells and zebrafish embryos, which were identified using a membrane non-permeable DRAQ7, a fluorescent nucleus staining dye; (4) We identified the cytotoxic compounds jegosaponin A and B from SJSZ, which we showed to exhibit cell membrane disruptive properties using cell- and zebrafish-based testing. 相似文献