全文获取类型
收费全文 | 258篇 |
免费 | 7篇 |
国内免费 | 5篇 |
出版年
2023年 | 1篇 |
2021年 | 8篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 9篇 |
2012年 | 10篇 |
2011年 | 6篇 |
2010年 | 4篇 |
2009年 | 7篇 |
2008年 | 3篇 |
2007年 | 6篇 |
2006年 | 12篇 |
2005年 | 3篇 |
2004年 | 14篇 |
2003年 | 11篇 |
2002年 | 13篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 6篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1993年 | 10篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 9篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 3篇 |
1975年 | 1篇 |
排序方式: 共有270条查询结果,搜索用时 78 毫秒
91.
Abstract The effects of light and gibberellic acid (GA3) on growth and phenylalanine ammonia-lyase (PAL) activity were studied in seedlings of lettuce (Lactuca sativa L.). Using an in vivo assay for PAL it was shown that wounding caused by excising hypocotyls results in an increase in PAL activity with time that can mask the effect of light on the activity of this enzyme. When hypocotyl sections were excised from light-treated seedlings immediately prior to the in vivo assay of PAL, light was shown to cause a marked increase in PAL activity. Experiments with an inhibitor of PAL activity, α-aminooxy-β-phenylpropionic acid (AOPP), confirmed that the volatile radioactive products measured in the in vivo assay resulted from the activity of PAL. Gibberellic acid suppresses the light-induced increase in PAL activity and there is an inverse relationship between GA3-induced growth and the activity of PAL. Over a wide range of GA3 concentrations, the activity of PAL is also inversely correlated with growth rate along the length of the hypocotyl section; the upper halves of sections elongate more rapidly and have lower levels of PAL than the lower halves. Despite the strong correlation between growth and PAL activity, experiments with AOPP and t-cinnamic acid show that it is unlikely that elongation is regulated directly by products of PAL activity. 相似文献
92.
93.
94.
独行菜种子下胚轴伸长存在低温停滞现象,是研究温度对植物下胚轴伸长影响的良好材料。为了揭示下胚轴伸长相关转录因子HY5在独行菜下胚轴低温伸长中的作用,该研究从独行菜种子转录组中获得LaHY5序列,并进行了克隆、序列分析,通过实时定量PCR技术研究了该基因表达与低温诱导及萌发阶段的关系,并通过转化拟南芥分析该基因表达对下胚轴低温伸长的影响。结果表明:(1)LaHY5基因的cDNA序列包含447 bp的完整阅读框序列,其编码产物为富含丝氨酸的149个氨基酸组成的肽链,包含典型的BRLZ结构域,相对分子质量为16.830 kD,分子式为C_(692)H_(1156)N_(228)O_(246)S_7,理论等电点为8.73,与十字花科植物同源序列高度一致。(2)LaHY5基因在独行菜萌发过程中的种子或幼苗中受低温诱导快速上调表达。(3)转LaHY5基因拟南芥种子在常温或低温条件下,下胚轴伸长均比野生型植株快。研究表明,LaHY5转录因子在种子低温萌发及幼苗耐受低温胁迫中起重要作用,但LaHY5基因并不是造成独行菜下胚轴伸长低温停滞的限制性因素。 相似文献
95.
GARY GARDNER CHENTAO LIN ELAINE M. TOBIN HEATHER LOEHRER & DOUG BRINKMAN 《Plant, cell & environment》2009,32(11):1573-1583
Alteration of 'normal' levels of ultraviolet-B light (UV-B, 280–320 nm) can affect plant chemical composition as well as growth; however, little is known about how plants perceive UV-B light. We have carried out fluence response curves, and demonstrated that the growth inhibition of etiolated Arabidopsis thaliana seedlings by low fluence UV light is specific to UV-B and not UV-A (320–390 nm). The response shows reciprocity between duration and intensity, at least over a limited range, and thus depends only on photon fluence and not on photon flux. The action spectrum for this response indicates a peak of maximum effectiveness at 290 nm, and response spectra at different fluences indicate that the most effective wavelength at 30 000 µ mol m–2 is 290 nm, whereas 300 nm light was the most effective at 100 000 µ mol m–2 . This response occurs in mutant seedlings deficient in cryptochrome, phytochrome or phototropin, suggesting that none of the known photoreceptors is the major UV-B photoreceptor. Some null mutants in DNA repair enzymes show hypersensitivity to UV-B, suggesting that even at low fluence rates, direct damage to DNA may be one component of the response to UV-B. 相似文献
96.
97.
98.
99.
研究了一氧化氮(NO)供体普钠(SNP)、一氧化氮清除剂C-PTIO和一氧化氮合酶(NOS)抑制L-NAME对绿豆(Vigna radiataL.)下胚轴插条生根的影响.并对不定根生期间手条基部NO 和NADPH-黄递酶的时空变化进行了检测.所试浓度SNP均明显促进下胚轴不根发生.分别插条切取后24h和36h于其基部维管束之间检测到NADPH-黄递酶(NOS标记酶)阳性反应和NO荧光,根原基也于48h在相同位置出现,并于60h进一步伸长.48~60h期间,NADPH、黄递的阳性反应及NO荧光有增强趋势,并主要分布在不定根分生组织中.L-NAME既减弱NADPH-黄递酶的阳性反应和NO荧光,也延缓不不定根发生;而c-PTIO对NO荧光及不定根生均有抑制作用.上述结果证明:NO在不定根发生及发育过程中有重要作用,而且此过程中的NO很可能由类似的NOS催化产生. 相似文献
100.