全文获取类型
收费全文 | 449篇 |
免费 | 8篇 |
国内免费 | 5篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 24篇 |
2012年 | 5篇 |
2011年 | 5篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 20篇 |
2007年 | 15篇 |
2006年 | 19篇 |
2005年 | 16篇 |
2004年 | 13篇 |
2003年 | 12篇 |
2002年 | 22篇 |
2001年 | 19篇 |
2000年 | 12篇 |
1999年 | 16篇 |
1998年 | 10篇 |
1997年 | 13篇 |
1996年 | 17篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 14篇 |
1992年 | 16篇 |
1991年 | 11篇 |
1990年 | 11篇 |
1989年 | 17篇 |
1988年 | 11篇 |
1987年 | 13篇 |
1986年 | 8篇 |
1985年 | 17篇 |
1984年 | 12篇 |
1983年 | 6篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有462条查询结果,搜索用时 15 毫秒
101.
Calcium-dependent protein kinase gene expression in response to physical and chemical stimuli in mungbean (Vigna radiata) 总被引:5,自引:0,他引:5
Jose R. Botella Jeannette M. Arteca Maria Somodevilla Richard N. Arteca 《Plant molecular biology》1996,30(6):1129-1137
Protein kinases are important in eukaryotic signal transduction pathways. In this study we designed degenerate oligonucleotides corresponding to two conserved regions of protein kinases and using the polymerase chain reaction (PCR) have amplified a 141 bp fragment of DNA from mungbeans (Vigna radiata Rwilcz cv. Berken). Sequence analysis of the PCR products indicates that they encode several putative protein kinases with respect to their identity with other known plant protein kinases. Using one of the six fragments (CPK3-8), we isolated a 2022 bp cDNA (VrCDPK-1) from a Vigna radiata gt11 library. VrCDPK-1 has a 96 bp 5-untranslated region and a 465 bp 3-untranslated region and an open reading frame of 1461 bp. VrCDPK-1 contains all of the conserved regions commonly found in calcium dependent protein kinases (CDPK). VrCDPK-1 shares 24 to 89% sequence identity with previously reported sequences for plant CDPKs at the protein level. southern analysis revealed the presence of several copies of the CDPK gene. VrCDPK-1 expression was stimulated when mungbean cuttings were treated with CaCl2, while treatment with MgCl2 had no effect. We are reporting for the first time a CDPK gene in mungbean which is inducible by mechanical strain. Cuttings treated with indole-3-acetic acid (IAA) or subjected to salt stress showed an increase in VrCDPK-1 expression. There was a dramatic stimulation in VrCDPK-1 expression 6 h after cuttings were treated with cycloheximide. 相似文献
102.
Marianne Bordenave Christelle Breton Renée Goldberg Jean-Claude Huet Serge Perez Jean-Claude Pernollet 《Plant molecular biology》1996,31(5):1039-1049
Peptide maps and partial amino acid sequences of the 3 main pectinmethylesterases (PMEs) solubilized from mung bean hypocotyl cell walls demonstrated that these proteins were different isozymes originating from a small multigene family. A cDNA clone encoding the most alkaline PME (PE) have been obtained by PCR using degenerate oligonucleotide primers. Combining the protein and nucleotide sequencing data, the complete amino acid sequence of PE was determined. The nature protein is composed of 318 amino acids with a calculatedM
r
of 34 677 and an estimated pI of 9.84 consistent with the values previously obtained by SDS-PAGE and IEF. It shares most of the conserved regions of previously known PMEs. Enzymatic activities of the three isoforms were differently affected by the presence of cations in the incubation medium but, in all cases, infra-optimal cation concentrations induced two opposite effects: a decrease in theV
max
and an increase in the affinity of the enzymes for their substrate. The presence of cations in the assay modulates both the number of enzyme molecules available to the demethylation reaction and the conformation of the pectin and, in turn, the affinity of the PMEs for their substrate. 相似文献
103.
以转录抑制剂放线菌素D和转译抑制剂环己亚胺为工具的实验表明,4-氯苯氧乙酸(CPA)与2,4-D促进绿豆幼苗中的细胞色素氧化酶同工酶的活性,是由于刺激了种子中预存mRNA转译的结果。此外,发现环己亚胺对酯酶同工酶的活性有非常明显的刺激作用,其原因尚待进一步研究。 相似文献
104.
J. S. Gill M. M. Verma R. K. Gumber J. S. Brar 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1995,90(3-4):554-560
The comparative efficiency of four selection methods, viz., honeycomb (HC), pedigree selection (PS), single-seed descent (SSD) and the bulk method (BM), was assessed in three crosses of mungbean. The lines derived by each method, along with check varieties, were yield-tested in a compact family block design in F5 and F6 generations during summer and kharif of 1990. On the basis of the mean of the lines, the range, the number of superior lines over the best check, and the proportion of the top 10% lines in all the crosses and generations, the honeycomb method exhibited superiority over PS, SSD and BM for yield per plant and its component traits. PS, SSD and BM did not differ from each other. The honeycomb and SSD methods were found suitable for deriving superior lines for seed yield and pods per plant in mungbean. 相似文献
105.
The experiment was made by using different concentrations of polyethylene glycol (PEG) or salt solutions to decrease the osmotic
potential of the growth medium to reveal the response of mung bean (Vigna radiata) to water and salt stresses. No germination
(emergence of the seedling) occurred at medium osmotic potential lower than -1.0 MPa in all treatments. It was found that
the activity of α-amylase and protease, and contents of proline, saccharides and the soluble proteins decreased in the germinating
seeds during 3-d stress. However, after 10-d stress, the contents of organic solutes and the activity of the hydrolytic enzymes
increased. Growth, chlorophyll content and mineral uptake were also significantly reduced under stress. The seedlings under
water stress induced by PEG were affected much more than under salinity. This may be due to the maintenance of a higher succulence
under salt stress than under PEG-induced water stress.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
106.
Mature de-embryonated cotyledons with intact proximal end of Vigna unguiculata were cultured on B5 basal medium containing varying concentrations of BAP. Thirty-six percent of the explants produced shoots on B5 medium supplemented with 8× 10–6 M BAP. Cotyledon explants were pre-incubated for 24 h, inoculated with A. tumefaciens pUCD2614 carrying pUCD2340, co-cultivated for 48 h and transferred to hygromycin-B (25 mg/l) containing shoot induction medium. Approximately 15–19% of the explants produced shoots on the selection medium. The elongated shoots were subsequently rooted on B5 basal medium containing hygromycin. The transgenic plants were later established in pots. The presence of hpt gene in the transgenic plants was confirmed by Southern blot hybridization.Abbreviations BAP
6-Benzylaminopurine
- 2,4-D
2,4-dichlorophenoxyacetic acid
-
hpt
hygromycin phosphotransferase
- IAA
Indole-3-acetic acid
- NAA
1-naphthaleneacetic acid 相似文献
107.
A. Pellegrineschi C. A. Fatokun G. Thottappilly A. A. Adepoju 《Plant cell reports》1997,17(2):133-138
Factors responsible for successful rescue of immature embryos of cowpea [Vigna unguiculata (L.) Walp.] and V. vexillata (L.) and for in vitro embryo development were studied. A new basal medium for embryo development in vitro was formulated
on the basis of the mineral composition of embryos. Sucrose, fructose and glucose were compared as carbohydrate sources. The
highest frequency of embryos developing into plants was obtained with sucrose. Adding casein hydrolysate to the medium increased
plant recovery by 30%. Among the plant growth factors used, cytokinins, zeatin, 6-benzylaminopurine and kinetin were the most
effective in promoting embryo maturation and development. A method that can routinely ensure high plant recovery from cultured
immature cowpea embryos is proposed.
Received: 4 June 1996 / Revision received: 28 October 1996 / Accepted: 22 November 1996 相似文献
108.
A. Pellegrineschi 《Plant cell reports》1997,17(2):89-95
Shoot regeneration via organogenesis was achieved from axenic cowpea [Vigna unguiculata subsp. unguiculata L. (Walp.) Verde.] hypocotyls and cotyledons of advanced breeding lines and varieties. Cotyledons and embryos were excised
from green immature pods. The apical parts of the embryos were removed and the hypocotyls were transferred to regeneration
media. Cotyledons and hypocotyls were tested on media with gradients of several hormonal and putrescine combinations. Cowpea
cotyledons and hypocotyls exhibited a pattern of shoot formation that occurred in three distinct phases. Multiple shoots developed
within 45 days from the wounded region of the primary hypocotyl and cotyledons in different media containing a high cytokinin
concentration. The induced plant explants were then grown for 20 days in low-intensity light (10 μmol m–2 s–1) on the same medium and numerous shoot buds emerged de novo from the upper part of the hypocotyl and the wounded part of the cotyledons. These buds had no apparent vascular connection
with the parent tissues. The plant regeneration capability of this procedure was tested with several cowpea genotypes, five
of which (83D-442, 86D-1010, 93K-624, Vita 3 and Ife Brown) responded positively with shoot development and were able to form
roots and whole plants. Some somaclonal variation was observed.
Received: 14 June 1996 / Revision received: 14 December 1996 / Accepted: 25 January 1997 相似文献
109.
Little is known about whether the high N losses from inorganic N fertilizers applied to lowland rice (Oryza sativa L.) are affected by the combined use of either legume green manure or residue with N fertilizers. Field experiments were
conducted in 1986 and 1987 on an Andaqueptic Haplaquoll in the Philippines to determine the effect of cowpea [Vigna unguiculata (L.) Walp.] cropping systems before rice on the fate and use efficiency of15N-labeled, urea and neem cake (Azadirachta indica Juss.) coated urea (NCU) applied to the subsequent transplanted lowland rice crop. The pre-rice cropping systems were fallow,
cowpea incorporated at the flowering stage as a green manure, and cowpea grown to maturity with subsequent incorporation of
residue remaining after grain and pod removal. The incorporated green manure contained 70 and 67 kg N ha−1 in 1986 and 1987, respectively. The incorporated residue contained 54 and 49 kg N ha−1 in 1986 and 1987, respectively. The unrecovered15N in the15N balances for 58 kg N ha−1 applied as urea or NCU ranged from 23 to 34% but was not affected by pre-rice cropping system. The partial pressure of ammoniapNH3, and floodwater (nitrate + nitrite)-N following application of 29 kg N ha−1 as urea or NCU to 0.05-m-deep floodwater at 14 days after transplanting was not affected by pre-rice cropping system. In
plots not fertilized with urea or NCU, green manure contributed an extra 12 and 26 kg N ha−1, to mature rice plants in 1986 and 1987, respectively. The corresponding contributions from residue were 19 and 23 kg N ha−1, respectively. Coating urea with 0.2g neem cake per g urea had no effect on loss of urea-N in either year; however, it significantly
increased grain yield (0.4 Mg ha−1) and total plant N (11 kg ha−1) in 1987 but not in 1986. 相似文献
110.
The effect of water deficit on nodulation, N2 fixation, photosynthesis, and total soluble sugars and leghemoglobin in nodules was investigated in cowpea and groundnut. Nitrogenase activity completely ceased in cowpea with a decrease in leaf water potential (
leaf) from –0.4 MPa to –0.9 MPa, while in groundnut it continued down to –1.7 MPa. With increasing water stress, the acetylene reduction activity (ARA) declined very sharply in cowpea, but ARA gradually decreased in groundnut. Even with mild water stress (
leaf of 0.2 MPa), nodule fresh weight declined 50% in cowpea partly due to a severe nodule shedding whereas nodule fresh weight declined in groundnut only when
leaf decreased by 1.0 MPa. No nodule shedding was noticed even at a higher stress level in groundnut. Photosynthesis and stomatal conductance were also more stable in groundnut than in cowpea under water stress. There was a sharp increase in total soluble sugars and leghemoglobin in the nodules of groundut with water stress, but no definite trend could be found in cowpea. 相似文献