全文获取类型
收费全文 | 304篇 |
免费 | 32篇 |
专业分类
336篇 |
出版年
2021年 | 6篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 11篇 |
2015年 | 18篇 |
2014年 | 12篇 |
2013年 | 27篇 |
2012年 | 19篇 |
2011年 | 22篇 |
2010年 | 12篇 |
2009年 | 9篇 |
2008年 | 12篇 |
2007年 | 16篇 |
2006年 | 16篇 |
2005年 | 6篇 |
2004年 | 12篇 |
2003年 | 10篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1972年 | 5篇 |
1971年 | 3篇 |
1970年 | 1篇 |
1969年 | 4篇 |
1968年 | 7篇 |
1967年 | 4篇 |
1966年 | 6篇 |
1965年 | 2篇 |
1964年 | 1篇 |
排序方式: 共有336条查询结果,搜索用时 26 毫秒
71.
An efficient in vitro method for mass propagation of a woody ornamentalIxora coccinea L. 总被引:1,自引:0,他引:1
Various factors that affect culture establishment, shoot growth, proliferation and rooting ofIxora coccinea L., a woody shrub, were studied. Stem cuttings (decapitated shoot, three nodes) were the most suitable explants for multiple-shoot proliferation, and when cultured on a woody plant medium (WPM) containing 2.5 M BA produced axillary shoots which branched repeatedly, yielding an average of 27 shoots per explant after 6 weeks in culture. Kinetin, 2-iP, zeatin and thidiazuron all induced multiple-shoot formation, but were less effective than BA. While the presence of IAA in the multiplication medium was detrimental to shoot proliferation, shoot growth was not affected by IAA. The production of large amounts of basal callus and vitrification of shoots were the major problems to be avoided in proliferating shoot cultures. Addition of TIBA to the multiplication medium markedly reduced basal callusing, while sealing the culture vessels with a fluorocarbon polymer (tetrafluoroethyleneperfluoroalkyl vinyl ether) film (Neoflon PFA film) almost completely eliminated vitrification. A reduction in the number of vitrified shoots was also achieved with AVG treatment. Following this protocol of using BA-supplemented WPM and Neoflon film, it would be possible to produce more than 100,000 plants from a single stem cutting in 1 year.Abbreviations
AVG
Aminoethoxyvinylglycine
-
BA
N6-benzyladenine
-
BM
basal medium
-
IAA
indole-3-acetic acid
-
IBA
indole-3-butyric acid
-
2-tiP
N6-(2-isopentenyl)adenine
-
KIN
kinetin
-
MS
Murashige and Skoog medium
-
NAA
-naphthaleneacetic acid
-
SRM
shoot regeneration medium
-
TDZ
thidiazuron
-
TIBA
2,3,5-triiodobenzoic acid
-
WPM
woody plant medium
-
ZEA
zeatin 相似文献
72.
Bryce, J. H. and ap Rees, T. 1985. Comparison of the respiratorymetabolism of Plantago lanceolata L. and Plantago major L.J.exp. Bot. 36 15591565. The aim of this work was to discover if the respiratory metabolismof the roots of Plantago lanceolata L. differed from that ofthe roots of Plantago major L. Measurements of oxygen uptakeand dry weight of excised root systems during growth of seedlingsprovided evidence that the two species differed in the amountof respiration needed to support a given increase in dry weight.Excised root systems were given a 6-h pulse in [U-14C]sucrosefollowed by a 16.5-h chase in sucrose. The detailed distributionof 14C amongst the major components of the roots at the endof the pulse and the chase revealed no significant differencebetween the two species. Patterns of 14CO2 production from [1-14C],[2-14C], [3,4-14C], and [6-14C]glucose of excised root systemsfrom plants of three ages were similar for the two species.It is suggested that there is no conclusive evidence for anysignificant inherent difference in the respiratory metabolismof the roots of the two species. Key words: 14C sugar metabolism, respiration, roots, Plantago 相似文献
73.
74.
Bandyopadhyay A Lakshmanan V Matsumoto T Chang EC Maitra U 《The Journal of biological chemistry》2002,277(3):2360-2367
The protein encoded by the fission yeast gene, moe1(+) is the homologue of the p66/eIF3d subunit of mammalian translation initiation factor eIF3. In this study, we show that in fission yeast, Moe1 physically associates with eIF3 core subunits as well as with 40 S ribosomal particles as a constituent of the eIF3 protein complex that is similar in size to multisubunit mammalian eIF3. However, strains lacking moe1(+) (Deltamoe1) are viable and show no gross defects in translation initiation, although the rate of translation in the Deltamoe1 cells is about 30-40% slower than wild-type cells. Mutant Deltamoe1 cells are hypersensitive to caffeine and defective in spore formation. These phenotypes of Deltamoe1 cells are similar to those reported previously for deletion of the fission yeast int6(+) gene that encodes the fission yeast homologue of the p48/Int6/eIF3e subunit of mammalian eIF3. Further analysis of eIF3 subunits in Deltamoe1 or Deltaint6 cells shows that in these deletion strains, while all the eIF3 subunits are bound to 40 S particles, dissociation of ribosome-bound eIF3 results in the loss of stable association between the eIF3 subunits. In contrast, eIF3 isolated from ribosomes of wild-type cells are associated with one another in a protein complex. These observations suggest that Moe1 and spInt6 are each required for stable association of eIF3 subunits in fission yeast. 相似文献
75.
The phytohormone crosstalk paradigm takes center stage in understanding how plants respond to abiotic stresses 总被引:4,自引:0,他引:4
Ajay Kohli Nese Sreenivasulu Prakash Lakshmanan Prakash P. Kumar 《Plant cell reports》2013,32(7):945-957
The highly coordinated, dynamic nature of growth requires plants to perceive and react to various environmental signals in an interactive manner. Elaborate signaling networks mediate this plasticity in growth and the ability to adapt to changing environmental conditions. The fluctuations of stress-responsive hormones help alter the cellular dynamics and hence play a central role in coordinately regulating the growth responses under stress. Recent experimental data unequivocally demonstrated that interactions among various phytohormones are the rule rather than exception in integrating the diverse input signals and readjusting growth as well as acquiring stress tolerance. The presence of multiple and often redundant signaling intermediates for each phytohormone appears to help in such crosstalk. Furthermore, there are several examples of similar developmental changes occurring in response to distinct abiotic stress signals, which can be explained by the crosstalk in phytohormone signaling. Therefore, in this brief review, we have highlighted the major phytohormone crosstalks with a focus on the response of plants to abiotic stresses. The recent findings have made it increasingly apparent that such crosstalk will also explain the extreme pleiotropic responses elicited by various phytohormones. Indeed, it would not be presumptuous to expect that in the coming years this paradigm will take a central role in explaining developmental regulation. 相似文献
76.
77.
78.
79.
Balathandayuthabani Panneer Selvam Sivakiruthika Natchimuthu Lakshmanan Arunachalam David Bastviken 《Global Change Biology》2014,20(11):3397-3407
Inland waters were recently recognized to be important sources of methane (CH4) and carbon dioxide (CO2) to the atmosphere, and including inland water emissions in large scale greenhouse gas (GHG) budgets may potentially offset the estimated carbon sink in many areas. However, the lack of GHG flux measurements and well‐defined inland water areas for extrapolation, make the magnitude of the potential offset unclear. This study presents coordinated flux measurements of CH4 and CO2 in multiple lakes, ponds, rivers, open wells, reservoirs, springs, and canals in India. All these inland water types, representative of common aquatic ecosystems in India, emitted substantial amounts of CH4 and a major fraction also emitted CO2. The total CH4 flux (including ebullition and diffusion) from all the 45 systems ranged from 0.01 to 52.1 mmol m?2 d?1, with a mean of 7.8 ± 12.7 (mean ± 1 SD) mmol m?2 d?1. The mean surface water CH4 concentration was 3.8 ± 14.5 μm (range 0.03–92.1 μm ). The CO2 fluxes ranged from ?28.2 to 262.4 mmol m?2 d?1 and the mean flux was 51.9 ± 71.1 mmol m?2 d?1. The mean partial pressure of CO2 was 2927 ± 3269 μatm (range: 400–11 467 μatm). Conservative extrapolation to whole India, considering the specific area of the different water types studied, yielded average emissions of 2.1 Tg CH4 yr?1 and 22.0 Tg CO2 yr?1 from India's inland waters. When expressed as CO2 equivalents, this amounts to 75 Tg CO2 equivalents yr?1 (53–98 Tg CO2 equivalents yr?1; ± 1 SD), with CH4 contributing 71%. Hence, average inland water GHG emissions, which were not previously considered, correspond to 42% (30–55%) of the estimated land carbon sink of India. Thereby this study illustrates the importance of considering inland water GHG exchange in large scale assessments. 相似文献
80.
On efficient probability forecasting systems 总被引:1,自引:0,他引:1