全文获取类型
收费全文 | 725篇 |
免费 | 44篇 |
国内免费 | 68篇 |
出版年
2023年 | 12篇 |
2022年 | 7篇 |
2021年 | 6篇 |
2020年 | 19篇 |
2019年 | 11篇 |
2018年 | 13篇 |
2017年 | 19篇 |
2016年 | 18篇 |
2015年 | 15篇 |
2014年 | 19篇 |
2013年 | 39篇 |
2012年 | 11篇 |
2011年 | 17篇 |
2010年 | 20篇 |
2009年 | 30篇 |
2008年 | 40篇 |
2007年 | 32篇 |
2006年 | 42篇 |
2005年 | 30篇 |
2004年 | 35篇 |
2003年 | 29篇 |
2002年 | 21篇 |
2001年 | 26篇 |
2000年 | 24篇 |
1999年 | 24篇 |
1998年 | 30篇 |
1997年 | 27篇 |
1996年 | 13篇 |
1995年 | 23篇 |
1994年 | 10篇 |
1993年 | 13篇 |
1992年 | 18篇 |
1991年 | 18篇 |
1990年 | 31篇 |
1989年 | 18篇 |
1988年 | 15篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有837条查询结果,搜索用时 15 毫秒
171.
172.
S. Kobayashi T. Ohgawara K. Fujiwara I. Oiyama 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1991,82(1):6-10
Summary Somatic hybrid plants were produced by protoplast fusion of navel orange and Murcott tangor. Hybridity of the plants was confirmed by the restriction endonuclease analysis of nuclear ribosomal DNA. All of the plants (16 clones) were normal, uniform, and had the amphidiploid chromosome number of 36 (2n=2x=18 for each parent). The cpDNA analysis showed that each of the 16 somatic hybrids contained either one parental chloroplast genome or the other. In all cases, the mitochondrial genomes of the regenerated somatic hybrids were of the navel orange type.Contribution No. E-132 of the Fruit Tree Research Station 相似文献
173.
Competition and fruit set in the Washington navel orange 总被引:2,自引:0,他引:2
In the Washington navel orange [ Citrus sinensis (L.) Osbeck] an increase in the number of flowers results in a reduction of flower weight at anthesis and the initial fruit growth rate, and the number of developing fruitlets increases. Most of these fruitlets are shed during post-anthesis, and the final set of fruit is unrelated to the number of flowers and to the total amount of metabolites and mineral elements used up in fructification but appears to be controlled by the capacity of the tree to supply metabolites to the developing fruitlets during post-anthesis. When the number of flowers is too large, there is a reduction both in the number of initially developing fruitlets and in their growth rate. The final set of fruit is reduced through a different mechanism acting at anthesis and involving differences in mineral composition, which impairs the capacity of the fruit to act as a sink. 相似文献
174.
175.
The fate of [14C] gibberellin A3 and [3H] gibberellin A1 was examined in senescing fruit of Shamouti orange (Citrus sinensis L. Osbeck) and tomato (Lycopersicon esculentum Mill.). Gibberellin A3 was highly persistent in Citrus peel (t 1/2=18 days) and to a lesser degree in tomato (t 1/2=5.5 days). Ethylene and ethephon caused a slight enhancement of gibberellin A3 metabolism in Citrus and tomato fruit, respectively. Gibberellin A1 was metabolized by Citrus peel at a relatively high rate (t 1/2 < 24 h) and ethylene slightly reduced this rate. It is concluded that the ethylene-induced enhancement of senescence does not involve major effects on the deactivation of applied gibberellins.Abbreviations GA3
gibberellin A3
- GA1
gibberellin A1 相似文献
176.
Eliezer E. Goldschmidt 《Plant Growth Regulation》1984,2(1):9-13
The relationship of abscisic acid (ABA) and 2-trans-abscisic acid (t-ABA) to alternate bearing has been examined in Wilking mandarin (Citrus reticulata Blanco) trees. Leaves, stems and buds of trees loaded with fruit (on trees) had 4.3, 6.0 and 2.2 fold higher ABA levels than the corresponding organs from off trees. Leaves had higher ABA levels than stems and buds in both on and off trees. t-ABA was non-detectable in Wilking leaf, stem and bud tissue. Amounts of t-ABA not exceeding 40% of the ABA content, were found in Shamouti and Valencia orange buds and in Wilking fruit peel.The elevated levels of ABA in on tree organs may reflect a stress imposed by the fruit overload. 相似文献
177.
Investigations were undertaken to determine the suitability of sucrose and magnesium sulphate solutions and a silica colloidal suspension with centrifugation for extracting Tylenchulus semipenetrans from citrus roots. The efficiency of incubation, sodium hypochlorite, centrifugation, and maceration methods was also compared. Numbers of females recovered by centrifugation with colloidal silica were greater than those from sucrose or magnesium sulphate. Incubation, sodium hypochlorite, and centrifugation methods were satisfactory for extracting eggs, second-stage juveniles, and males, whereas the maceration-sieving method was less efficient. Combining the sodium hypochlorite method with a 15-second maceration followed by centrifugation in colloidal silica reduced the recovery of T. semipenetrans females from citrus roots. 相似文献
178.
To effectively conserve sour orange (Citrus aurantium L.) germplasm on two Islands at the estuary of the Yangtze River In China, we estimated genetic variation and relationships of the known parental trees and their proposed descendents (young trees) using the fingerprinta of random amplified polymorphic DHA (RAPD). Results based on RAPD analyses showed considerable genetic diversity In the parental populations (H<,e> = 0.202). The overall populations including the parental and young trees showed slightly higher genetic diversity (H<,e> = 0.298) than the parents, with about 10% variation between populations. An unweighted pair group method with arithmetic mean analysis dendrogram based on cluster analysis of the Jaccard similarity among individuals demonstrated a more complicated relationship of the parental and young trees from the two islands, although the young trees showed a clear association with parental trees. This indicates a slgnificant contribution of parental trees in establishing the sour orange populations on the two islands. According to farmers' knowledge, conservation of only one or two parental trees would be sufficient because they believed that the whole populations were generated from a single mother tree. However, this study suggests that preserving most parental trees and some selected young trees with distant genetic relationships should be an effective conservation strategy for sour orange germplasm on the two islands. 相似文献
179.
Motoo Shibata Masaru Uyeda Yutaka Kido Motoharu Kinoshita Yasunori Kosugi Yoshiko Hashimoto 《Bioscience, biotechnology, and biochemistry》2013,77(10):2507-2509
A novel expression system was developed for the high level production of a labile protein in Escherichia coli. The regulatory signal of bacteriophage T4 uvsY gene was fused in frame with the coding region of human ventricular myosin alkali light chain (VLC1) gene. Expression from the regulatory signal was enhanced and continued in a lysis-inhibition state by infection with a cytosine-substituting T4 phage mutant. VLC1 protein was produced at a low level without infection because of its instability in the cells. Although the productivity was partly improved in a lon-deficient mutant without infection, it was improved about 100-fold with T4 phage infection. T4 phage produces protease inhibitor(s) (pin gene product) against proteases of host cell including the lon gene product (protease La). 相似文献
180.
Tetraploid plants are essential for interploid hybridization to create triploid seedless citrus. Here we report a simple and
efficient in vitro method for generating autotetraploids for sweet orange (Citrus sinensis). Cell-division activity in ‘Anliucheng’ sweet orange callus was analyzed using flow cytometry to determine the peak frequency
of cell division at which time callus in a liquid media and solid media was treated with 1000 mg l−1 colchicine. The percentage of the DNA-content-varied cells in the callus increased markedly from 11.0% to 44.4% and to 59.0%
for liquid and solid media respectively. A total of 20 tetraploid plantlets were recovered via embryogenesis from 47 plantlets
regenerated from the treated callus. All the autotetraploids were derived from different embryoids. Autotetraploids will be
useful parents for interploid hybridization to generate commercially valuable seedless triploid citrus cultivars. 相似文献