全文获取类型
收费全文 | 146篇 |
免费 | 11篇 |
专业分类
157篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 3篇 |
2019年 | 1篇 |
2018年 | 7篇 |
2017年 | 7篇 |
2016年 | 4篇 |
2015年 | 12篇 |
2014年 | 9篇 |
2013年 | 6篇 |
2012年 | 11篇 |
2011年 | 7篇 |
2010年 | 5篇 |
2009年 | 5篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 2篇 |
1994年 | 1篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1968年 | 1篇 |
1920年 | 1篇 |
1911年 | 1篇 |
排序方式: 共有157条查询结果,搜索用时 0 毫秒
151.
152.
Marcelo Rodrigues Patrícia Duarte de Oliveira Paiva João Paulo Rodrigues Alves Delfino Barbosa Thaís de Oliveira Fontes Mansur 《Acta Physiologiae Plantarum》2014,36(7):1893-1902
The calla lily (Zantedeschia aethiopica) is an ornamental plant with growing acceptance in the market place that shows thermal constraints during planting. This study aimed to analyse its biological cycle in growing degree days (GDD) to determine the best time for planting and production of flower stalks. Rhizomes were planted in pots during all four seasons, and the pots were kept in a greenhouse. Growth analysis and gas exchange measurements were performed every 30 days. Rhizomes planted in the fall and summer showed greater shoot growth, a larger root system and increased production of flower stalks, and they remained in the vegetative phase longer before the onset of flowering, attaining a lower GDD value. Rhizomes planted in winter and spring matured early, which resulted in a higher GDD value and a decrease or lack of flower stalk production during this period. Calla lily rhizomes planted in the fall and summer showed higher water-use efficiency, light-use efficiency and net photosynthesis. It is possible to characterise the stages of development according to gas exchange. The calla lily must be cultivated with an irradiance of 250–400 µmol m?2 s?1 in a temperature range of 25–28 °C during the initial growth phase (up to 1,000 GDD). Thereafter, the temperature range should be reduced to between 13 and 15 °C until 3,500 GDD are reached, which was found to enable increased flower stalk production. 相似文献
153.
154.
Claudia Simões Norma Albarello Cátia Henriques Callado Tatiana Carvalho de Castro Elisabeth Mansur 《Plant Cell, Tissue and Organ Culture》2009,98(1):79-86
Alternative methods for in vitro shoot culture of Cleome rosea, a Brazilian herbaceous species with ornamental value and medicinal potential, were evaluated. A protocol for rapid in vitro
multiplication of roots, a valuable source of medicinal compounds, was also developed. Stem explants were cultured in liquid
media (continuous immersion and paper bridge), while root explants were cultivated in continuous immersion and on solidified
media. The highest numbers of shoots, 20 ± 4.6 shoots/explant, were obtained from stem explants incubated in a continuous
immersion system in a liquid medium supplemented with 2.2 μM BA. Root explants cultivated in liquid media produced only hyperhydrous
adventitious shoots. However, these explants generated 5.8 ± 0.8 shoots/explant by indirect organogenesis when cultivated
on solidified medium supplemented with 2.2 μM BA. In addition, root multiplication was achieved in liquid medium in the presence
of α-naphthaleneacetic acid. Adventitious shoots developed on newly formed roots when inoculated on solidified medium supplemented
with 2.2 μM BA. Shoot microcuttings developed roots when transferred onto solidified MS medium without growth regulators.
Rooted microcuttings were efficiently acclimatized when transferred ex vitro. 相似文献
155.
K. H. Nicolaides G. Azar D. Byrne C. Mansur K. Marks 《BMJ (Clinical research ed.)》1992,304(6831):867-869
OBJECTIVE--To examine the significance of fetal nuchal translucency at 10-14 weeks'' gestation in the prediction of abnormal fetal karyotype. DESIGN--Prospective screening study. SETTING--The Harris Birthright Research Centre for Fetal Medicine, King''s College Hospital, London. SUBJECTS--827 fetuses undergoing first trimester karyotyping by amniocentesis or chorionic villus sampling. MAIN OUTCOME MEASURE--Incidence of chromosomal defects. RESULTS--The incidence of chromosomal defects was 3% (28 of 827 cases). In the 51 (6%) fetuses with nuchal translucency 3-8 mm thick the incidence of chromosomal defects was 35% (18 cases). In contrast, only 10 of the remaining 776 (1%) fetuses were chromosomally abnormal. CONCLUSION--Fetal nuchal translucency > or = 3 mm is a useful first trimester marker for fetal chromosomal abnormalities. 相似文献
156.
V. L. M. De Pádua M. C. Pestana M. Margis-Pinheiro D. E. De Oliveira E. Mansur 《In vitro cellular & developmental biology. Plant》2000,36(5):374-378
Summary Direct gene transfer into peanut intact embryonic leaflets was performed through electroporation. In transient β-glucuronidase
expression assays, maximal expression was obtained by using pulses of 625 V cm−1 in EPRm (modified electroporation) buffer supplemented with 75 μM NaCl. Kanamycin-resistant plants were obtained, and the presence of the nptII gene was demonstrated by PCR analysis. The positive effect of electroporation on the efficiency of in vitro regeneration was demonstrated. Explants submitted to field strengths between 500 and 625 V cm−1 displayed a significantly increased number of shoots and originated faster growing calluses relative to control explants.
Whereas in control explants callus formation occurred only at the petiolule, electroporated leaflets developed additional
organogenic calluses on the foliar lamina.
These authors have contributed equally to this work. 相似文献
157.