全文获取类型
收费全文 | 417篇 |
免费 | 14篇 |
国内免费 | 42篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 9篇 |
2018年 | 7篇 |
2017年 | 9篇 |
2016年 | 6篇 |
2015年 | 13篇 |
2014年 | 15篇 |
2013年 | 20篇 |
2012年 | 16篇 |
2011年 | 16篇 |
2010年 | 16篇 |
2009年 | 21篇 |
2008年 | 24篇 |
2007年 | 29篇 |
2006年 | 20篇 |
2005年 | 24篇 |
2004年 | 19篇 |
2003年 | 19篇 |
2002年 | 11篇 |
2001年 | 12篇 |
2000年 | 20篇 |
1999年 | 9篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 9篇 |
1995年 | 4篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 14篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 5篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有473条查询结果,搜索用时 46 毫秒
31.
The experiment was performed to evaluate the progenies of plant lines transgenic for auxin synthesis genes derived from Ri T-DNA.Four lines of the transgenic plants were self-crossed and the foreign auxin genes in plants of T5 generation were confirmed by Southern hybridization.Two lines,D1232 and D1653,showed earlier folding of expanding leaves than untransformed line and therefore had early initiation of leafy head.Leaf cuttings derived from plant of transgenic line D1653 produced more adventitious roots than the control whereas the cuttings from folding leaves had much more roots than rosette leaves at folding stage,and the cuttings from head leaves had more roots than rosette leaves at heading stage.It is demonstrated that early folding of transgenic leaf may be caused by the relatively higher concentration of auxin.These plant lines with auxin transgenes can be used for the study of hormonal regulation in differentiation and development of plant orgens and for the breeding of new variety with rapid growth trait. 相似文献
32.
33.
A cDNA clone for the cytosolic Cu/Zn superoxide dismutase (Cu/Zn SOD) from Chinese cabbage (Brassica campestris ssp.pekinensis) was isolated and its DNA sequence was determined. The cDNA clone contains a complete coding sequence which encodes a protein
of 152 amino acids and a 3-untranslated region including a poly A signal. The deduced amino acid sequence shows that it is
highly homologous to the Cu/Zn SODs from other plants (60–90%). The lack of a putative chloroplast targeting transit peptide
indicates that the clone represents a cytosolic form of Cu/Zn SOD. Genomic Southern hybridization suggests that cytosolic
Cu/Zn SOD genes are present in 1 or 2 copies per genome. 相似文献
34.
This study assessed potential probiotic Lactobacillus strains isolated from the feces of breast-fed infants and from Taiwanese pickled cabbage for their possible use in probiotic fermented foods by evaluating their (i) in vitro adhesive ability, resistance to biotic stress, resistance to pathogenic bacteria, and production of β-galactosidase; (ii) milk technological properties; and (iii) in vivo adhesive ability, intestinal survival and microbial changes during and after treatment. Five Lactobacillus isolates identified as Lactobacillus reuteri F03, Lactobacillus paracasei F08, Lactobacillus rhamnosus F14, Lactobacillus plantarum C06, and Lactobacillus acidophilus C11 that showed resistance to gastric juice and bile salts were selected for further evaluation of their probiotic properties. All the strains demonstrated the ability to adhere to Caco-2 cells, particularly, strain L. plantarum C06 and L. reuteri F03 showed satisfactory abilities, which were similar to that of the reference strain L. rhamnosus GG. The strains L. paracasei F08 and L. acidophilus C11 had the highest β-galactosidase activity. Most of the strains were resistant to aminoglycosides and vancomycin but sensitive to ampicillin, erythromycin, and penicillin. All the 5 strains elicited antibacterial activity against both Gram-positive (Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus) and -negative (Escherichia coli and Salmonella enterica) pathogens. Moreover, the strains L. reuteri F03, L. paracasei F08, and L. plantarum C06 could grow rapidly in milk without nutrient supplementation and reached 10? cfu/mL after 24 h of fermentation at 37 °C. The viable cell counts of the 3 strains remained above 10? cfu/mL after 21 d of storage at 4 °C. In the animal feeding trial, the number of intestinal lactobacilli increased significantly after administration of milk fermented with the 3 strains, and the counts of fecal coliforms and Clostridium perfringens were markedly reduced. Lactobacillus strains could also survive in the ileal intestinal tissue of the treated rats. Technologically interesting Lactobacillus isolates may be used in the future as probiotic starter cultures for manufacturing novel fermented foods. 相似文献
35.
A hydroponic trial was conducted to investigate effects of molybdenum (Mo) on ascorbate-glutathione cycle (AsA-GSH cycle)
metabolism in Chinese cabbage (Brassica campestris L. ssp. pekinensis). Mo was applied at four rates: 0, 0.01, 0.15 and 1.5 mg l−1. The concentrations of ascorbate, dehydroascorbate, reduced- and oxidized- glutathione, and activities of five key enzymes
in the AsA-GSH cycle were studied. The results showed that appropriate Mo application increased the fresh weight of Chinese
cabbage, but excess application of Mo (1.5 mg l−1 Mo) decreased the fresh weight. Total ascorbate and reduced ascorbate concentrations in the Chinese cabbage increased with
Mo application rates. Although no significant differences existed in DHA concentration between the different Mo regimes, but
it has an increase trend with the 0.01 mg l-1 Mo treatment, and then decreased with the Mo level increasing. No significant difference in GSH concentration was found between
the different Mo treatments. Compared with the control, the GSSG concentration decreased significantly in the 0.01 mg l−1 Mo treatment. The activities of APX, MDHAR, DHAR and GR increased due to Mo application. But the activity of AAO decreased
with increasing Mo application rates. It is hypothesized that Mo may promote the redox process and regeneration of ascorbic
acid, and affect the ability of anti-oxidation in the Chinese cabbage.
Responsible Editor: Jian Feng Ma. 相似文献
36.
37.
T. Sretenović-Rajičić S. Ninković B. Uzelać B. Vinterhalter D. Vinterhalter 《Russian Journal of Plant Physiology》2007,54(5):653-658
Two inbred lines of Brassica oleracea L. var. capitata were transformed with two Agrobacterium tumefaciens strains harboring resistance to herbicide Basta: AGL1/pDM805 and LBA4404/pGKB5 (LB5-1). Inoculated cotyledons and hypocotyls
provided equally good explants and manifested a high percentage of shoot regeneration on MS medium supplemented with 1 mg/l
benzyladenine and 0.5 mg/l indole-3-butyric acid. The P34I5 genotype was superior to P22I5 in shoot regeneration (48.1 vs. 26.9%), multiplication, and acclimation in the greenhouse (76 vs. 40%). A. tumefaciens AGL1/pDM805 provided more regenerated shoots per explant, especially in the case of cotyledon explants, and the higher transformation
rate (up to 35% vs. up to 12%) as compared to LB5-1. Putative transformants survived spraying with 10–30 mg/l phosphinothricin.
Transformation was confirmed by GUS assay and PCR analysis in T0 and T1 generations.
Published in Russian in Fiziologiya Rastenii, 2007, vol. 54, No. 5, pp. 738–743.
The text was submitted by the authors in English. 相似文献
38.
Min BW Cho YN Song MJ Noh TK Kim BK Chae WK Park YS Choi YD Harn CH 《Plant cell reports》2007,26(3):337-344
A mannose selection system was adapted for use in the Agrobacterium-mediated transformation of Chinese cabbage. This system makes use of the pmi gene that encodes phosphomannose isomerase, which converts mannose-6-phosphate to fructose-6-phosphate. Hypocotyl explants
from 4–5-day-old seedlings of Chinese cabbage inbred lines were pre-cultured for 2–3 days and then infected with Agrobacterium. Two genes (l-guluno-γ-lactone oxidase, GLOase, and jasmonic methyl transferase, JMT) were transformed into Chinese cabbage using the transformation procedure developed in this study. We found that supplementing
the media with 7 g l−1 mannose and 2% sucrose provides the necessary conditions for the selection of transformed plants from nontransformed plants.
The transformation rates were 1.4% for GLOase and 3.0% for JMT, respectively. The Southern blot analysis revealed that several independent transformants (T
0) were obtained from each transgene. Three different inbred lines were transformed, and most of the T
1 plants had normal phenotypes. The transformation method presented here for Chinese cabbage using mannose selection is efficient
and reproducible, and it can be useful to introduce a desirable gene(s) into commercially useful inbred lines of Chinese cabbage. 相似文献
39.
40.
为探讨钾肥类型对菜心(Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee)的作用效应,研究了不同钾肥类型和水平对菜心生长、细胞保护酶和内源激素的影响。结果表明,氯化钾或硫酸钾处理可提高菜心叶片的POD 和CAT 活性、IAA 和GA3 含量,降低MDA 含量,提高菜薹产量。随着钾水平的提高,叶片IAA 和GA3 含量、POD 和CAT 活性以及菜薹质量明显提高,MDA 含量降低。当施钾90 kg hm-2 时,叶片的GA3 和IAA 含量显著下降,而POD 活性和菜薹产量没有显著变化。在相同水平下,氯化钾与硫酸钾对植株生长、菜薹产量、叶片GA3 含量的影响不显著。当施钾0~90 kg hm-2 时,氯化钾处理的叶片POD 活性显著高于硫酸钾处理;而施钾135~180 kg hm-2 时,氯化钾处理的叶片POD 活性则显著低于硫酸钾处理。除了90 kg hm-2 氯化钾处理的CAT 活性和45 kg hm-2 氯化钾处理的MDA 含量低于硫酸钾处理以及90 kg hm-2 和180 kg hm-2 氯化钾处理的IAA 含量高于硫酸钾处理的外,相同水平氯化钾和硫酸钾处理的CAT 活性、MDA 含量和IAA 含量没有显著差异。可见,钾肥类型对菜心的活性氧代谢系统及内源激素含量有一定的影响,但氯化钾与硫酸钾对菜心的施用效果相当,生产上可采用氯化钾代替硫酸钾以节约肥料成本,K2O 施用量以90 kg hm-2 为宜。 相似文献