全文获取类型
收费全文 | 398篇 |
免费 | 18篇 |
国内免费 | 2篇 |
出版年
2022年 | 4篇 |
2021年 | 4篇 |
2019年 | 10篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 10篇 |
2015年 | 14篇 |
2014年 | 22篇 |
2013年 | 18篇 |
2012年 | 36篇 |
2011年 | 26篇 |
2010年 | 22篇 |
2009年 | 22篇 |
2008年 | 25篇 |
2007年 | 22篇 |
2006年 | 40篇 |
2005年 | 14篇 |
2004年 | 18篇 |
2003年 | 15篇 |
2002年 | 15篇 |
2001年 | 13篇 |
2000年 | 14篇 |
1999年 | 9篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有418条查询结果,搜索用时 15 毫秒
61.
Induction of Betalain Pigmentation in Hairy Roots of Red Beet under Different Radiation Sources 总被引:5,自引:0,他引:5
The effects of aluminum on lipid peroxidation and activities of antioxidative enzymes were investigated in detached rice leaves treated with 0 to 5 mM AlCl3 at pH 4.0 in the light. AlCl3 enhanced the content of malondialdehyde but not the content of H2O2. Superoxide dismutase activity was reduced by AlCl3, while catalase and glutathione reductase activities were increased. Peroxidase and ascorbate peroxidase activities were increased only after prolonged treatment, when toxicity occurred. The results give evidence that Al treatment caused oxidative stress and in turn, it caused lipid peroxidation. 相似文献
62.
Summary
In vitro plantlets of Phalaenopsis ‘Happy Valentine’, Neofinetia falcate Hu, Cymbidium kanran Makino, and Cymbidium goeringii Reichb. f. were grown under photoautotrophic [high photosynthetic photon flux (PPF), high CO2 concentration, and increased number of air exchanges] and heterotrophic (low PPF, low CO2 concentration, no air exchanges) culture conditions. After 40 d of culture, a significant difference in plantlet growth was
observed between the two cultures. Total fresh and dry mass were on average 1.5 times greater in photoautotrophic culture
than in heterotrophic culture. Higher net photosynthetic rates were also observed for Phalaenopsis in photoautotrophic culture. In photoautotrophic culture, little difference was observed in air temperature between the inside
and outside of the culture vessel, whereas in heterotrophic culture, air temperature inside the culture vessel was 1–2°C higher
than that outside the culture vessel. Relative humidity inside the culture vessel was remarkably different between the two
cultures: 83–85% in photoautotrophic culture and 97–99% in heterotrophic culture. These results indicated that growth and
net photosynthetic rate of in vitro orchid plantlets were susceptible to the culture environments such as PPF, CO2 concentration, relative humidity (RH), and the number of air exchanges, which would allow a more efficient micropropagation
system for these orchid plants. 相似文献
63.
64.
Murthy Hosakatte Niranjana Dandin Vijayalaxmi S. Park So-Young Paek Kee-Yoeup 《Applied microbiology and biotechnology》2018,102(17):7309-7317
Applied Microbiology and Biotechnology - Ginseng (Panax ginseng C. A. Meyer, Family Araliaceae) is one of the major medicinal and nutraceutical plants, which is native to oriental region. It is... 相似文献
65.
Performance characteristics of a reversible immunosensor with a heterobifunctional enzyme conjugate as signal generator 总被引:1,自引:0,他引:1
Factors that control the performance of a reversible immunosensor with an analyte (progesterone)-enzyme (horseradish peroxidase) conjugate as signal generator have been investigated. The conjugate is used in conjunction with two antibodies, which are specific to progesterone and to horseradish peroxidase, immobilized on two spatially separated polypropylene mesh discs. The conjugate and two antibodies are confined to an internal compartment of a microdialyzer by a semipermeable membrane. The small analyte from an external medium permeates across the membrane into the internal compartment where the analyte concentration determines the relative amounts of the bound conjugate on the two solid surfaces. By measuring two signals from the conjugate bound at two separate sites, we experimentally obtained time-response curves to a concentration pulse of the external analyte. A mathematical (kinetic) model describing the sensor system was developed and used for the determination of rate-limiting factors. In semicontinuous monitoring of the analyte concentrations, operation of the immunosensor with the enzyme conjugate as signal generator required special attention to (a) enzyme stability, (b) analyte permeation (dependence on medium components), and (c) kinetics related to the different accessibility to the same antibody of the small analyte (to be measured) vs. the larger counterpart on the enzyme conjugate (for signal generation). (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 221-231, 1997. 相似文献
66.
Endothelial STAT3 Activation Increases Vascular Leakage Through Downregulating Tight Junction Proteins: Implications for Diabetic Retinopathy
下载免费PDF全文
![点击此处可从《Journal of cellular physiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
67.
Elena V. Popova Eun-Jung Lee Chun-Hua Wu Eun-Joo Hahn Kee-Yoeup Paek 《Plant Cell, Tissue and Organ Culture》2009,97(3):337-343
Two-years-old Ginkgo biloba cell culture initiated from cotyledonary explants was cryopreserved by a simple desiccation method. Preliminary incubation
of callus clumps on MS preculture medium supplemented with 100 g l−1 sucrose and 2 mg l−1 ABA for 7 and 14 days resulted in accumulation of endogenous soluble sugars and was essential for cell culture post-cryopreservation
survival. The optimal time for the preculture on sucrose-and-ABA containing medium was found to be 14 days. The sufficient
desiccation duration was determined as 150 min. FCM profiles of calli maintained for 2 years remained stable and were not
affected by cryopreservation. 相似文献
68.
69.
Soon-Yong Choi Hee Yun Park Aron Paek Gil Seob Kim Seong Eun Jeong 《Molecules and cells》2009,28(6):575-581
Ornithine decarboxylase (ODC) is a rate-limiting enzyme in the biosynthesis of polyamines, which are essential for cell growth,
differentiation, and proliferation. This report presents the characterization of an ODC-encoding cDNA (SlitODC) isolated from
a moth species, the tobacco cutworm, Spodoptera litura (Lepidoptera); its expression in a polyamine-deficient strain of yeast, S. cerevisiae; and the recovery in polyamine levels and proliferation rate with the introduction of the insect enzyme. SlitODC encodes 448 amino acid residues, 4 amino acids longer than B. Mori ODC that has 71% identity, and has a longer C-terminus, consistent with B. mori ODC, than the reported dipteran enzymes. The null mutant yeast strain in the ODC gene, SPE1, showed remarkably depleted polyamine levels; in putrescine, spermidine, and spermine, the levels were > 7, > 1, and > 4%,
respectively, of the levels in the wild-type strain. This consequently caused a significant arrest in cell proliferation of
> 4% of the wild-type strain in polyaminefree media. The transformed strain, with the substituted SlitODC for the deleted endogenous ODC, grew and proliferated rapidly at even a higher rate than the wild-type strain. Furthermore,
its polyamine content was significantly higher than even that in the wild-type strain as well as the spe1-null mutant, particularly with a very continuously enhanced putrescine level, reflecting no inhibition mechanism operating
in the putrescine synthesis step by any corresponding insect ODC antizymes to SlitODC in this yeast system. 相似文献
70.
Boo-Ja Lee Sung-Kyu Kim Soo Bok Choi Ki-Jeong Kim Kyung-Hee Paek 《FEBS letters》2009,583(13):2315-917
Capsicum annuum L. Bugang exhibits a hypersensitive response against Tobacco mosaic virus (TMV) P0 infection. The C. annuumUDP-glucosyltransferase 1 (CaUGT1) gene was upregulated during resistance response to TMV and by salicylic acid, ethephon, methyl viologen, and sodium nitroprusside treatment. When the gene was downregulated by virus-induced gene silencing, a delayed HR was observed. In addition, free and total SA concentrations in the CaUGT1-downregulated hot pepper were decreased by 52% and 48% compared to that of the control plants, respectively. This suggested that the CaUGT1 gene was involved in resistance response against TMV infection by controlling the accumulation of SA. 相似文献