全文获取类型
收费全文 | 2563篇 |
免费 | 53篇 |
国内免费 | 184篇 |
出版年
2024年 | 1篇 |
2023年 | 11篇 |
2022年 | 13篇 |
2021年 | 13篇 |
2020年 | 14篇 |
2019年 | 25篇 |
2018年 | 27篇 |
2017年 | 18篇 |
2016年 | 28篇 |
2015年 | 61篇 |
2014年 | 81篇 |
2013年 | 115篇 |
2012年 | 72篇 |
2011年 | 116篇 |
2010年 | 97篇 |
2009年 | 190篇 |
2008年 | 209篇 |
2007年 | 228篇 |
2006年 | 188篇 |
2005年 | 136篇 |
2004年 | 152篇 |
2003年 | 145篇 |
2002年 | 81篇 |
2001年 | 76篇 |
2000年 | 78篇 |
1999年 | 98篇 |
1998年 | 77篇 |
1997年 | 72篇 |
1996年 | 61篇 |
1995年 | 51篇 |
1994年 | 46篇 |
1993年 | 39篇 |
1992年 | 42篇 |
1991年 | 38篇 |
1990年 | 29篇 |
1989年 | 20篇 |
1988年 | 11篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1973年 | 4篇 |
1972年 | 1篇 |
排序方式: 共有2800条查询结果,搜索用时 15 毫秒
31.
F. J. L. Aragão L. M. G. Barros A. C. M. Brasileiro S. G. Ribeiro F. D. Smith J. C. Sanford J. C. Faria E. L. Rech 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(1-2):142-150
Exploiting the biolistic process we have generated stable transgenic bean (Phaseolus vulgaris L.) plants with unlinked and linked foreign genes. Co-transformation was conducted using plasmid constructions containing a fusion of the gus and neo genes, which were co-introduced with the methionine-rich 2S albumin gene isolated from the Brazil nut and the antisense sequence of AC1, AC2, AC3 and BC1 genes from the bean golden mosaic geminivirus. The results revealed a co-transformation frequency ranging from 40% to 50% when using unlinked genes and 100% for linked genes. The introduced foreign genes were inherited in a Mendelian fashion in most of the transgenic bean lines. PCR and Southern blot hybridization confirmed the integration of the foreign genes in the plant genome. 相似文献
32.
C. Kaendler M. Fladung H. Uhrig 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,92(3-4):455-462
A successful hybridization of a diploid clone of Solanum tuberosum with a rolC-transgenic, diploid S. papita clone is reported. By using leaf expiants of this S. papita clone, which after transformation expressed kanamycin resistance, intact protoplasts were obtained, but these protoplasts did not develop to microcalli or regenerate to mature plants. However, protoplasts of the S. tuberosum clone showed a high capacity to regenerate plants from isolated protoplasts. On a medium containing Kanamycin only calli regenerated to plants, which revealed a rolC phenotype (reduced apical dominance with a large number of adventitious shoots and a pale green color of leaves) and later on turned out to be true hybrids. Self fusions of S. papita never developed to microcalli and those of S. tuberosum ceased to develop on the kanamycin-containing medium. Identification of somatic hybrids was done by RFLP and RAPD analysis. In the greenhouse, out of four selected hybrids only FK3.1 was successfully crossed with two standard S. tuberosum varieties (Datura, Desirée). Out of all the seeds germinated, only rolC-negative F1 seedlings were further characterized. Within the seedling population obvious differences were evident in respect of the S. papita and S. tuberosum characteristics. 相似文献
33.
茉莉酸甲酯对花生幼苗生长和抗旱性的影响 总被引:12,自引:0,他引:12
经过茉莉酸甲酯处理的花生幼苗,在形态、解剖和生理上都发生变化,其中以125mg/L处理最显著。处理后的植株幼苗矮化,叶小而厚,叶片贮水细胞大、蒸腾减弱、内源脱落酸和脯氨酸含量增多、过氧化物酶活性加大。由于水分的丧失减少,叶片水分的贮存增加,从而提高幼苗的抗旱性。 相似文献
34.
TransformationofOrychophragmusviolaceusUsingAgrobacteriumtumefaciensAndRegenerationofTransgenicPlantsa¥ZHOUJi-ming(周冀明);WEIZh... 相似文献
35.
36.
The stem of the peanut plant contains two lectins, a methyl -mannoside specific lectin (SL-I) and a lactose/cellobiose specific lectin (SL-II). These lectins are found to be developmentally regulated and maximum activites are observed in 3–4-weeks-old plants. The two lectins SL-I and SL-II have been purified from 3-week-old stem by affinity chromatography on Sephadex G-50 and guar gum matrices respectively. Both are glycosylated lectins and have the identical subunit molecular weight of 31 kDa. 相似文献
37.
Victoriano Garre Francisco J. Murillo Santiago Torres-Martínez 《Molecular & general genetics : MGG》1994,244(3):278-286
A 5.6 kb DNA fragment from the fungus Phycomyces blakesleeanus has been cloned and sequenced. The fragment contains a gene that probably codes for the enzyme acetyl-coenzyme A synthetase (facA). The amino acid sequence deduced for the P. blakesleeanns protein is highly homologous to those of acetyl-coA-synthetases from other organisms. When placed under the control of a constitutive promoter from Aspergillus nidulans, the cloned gene complemented a facA mutation of this organism. In P. blakesleeanns, the expression of facA is induced by acetate. 相似文献
38.
Michael M. Burrell Peter J. Mooney Margaret Blundy Dawn Carter Fiona Wilson John Green Keith S. Blundy Tom ap Rees 《Planta》1994,194(1):95-101
The aim of this work was to discover whether genetic manipulation of 6-phosphofructokinase [EC 2.7.1.11; PFK(ATP)] influenced the rate of respiration of tuber tissue of Solanum tuberosum L. Transgenic plants were produced that contained the coding sequence of the Escherichia coli pfkA gene linked to a patatin promoter. Expression of this chimaeric gene in tubers resulted in a 14to 21-fold increase in the maximum catalytic activity of PFK(ATP) without affecting the activities of the other glycolytic enzymes. Tubers, and aged disks of tuber tissue, from transformed plants showed no more than a 30% fall in the content of hexose 6-monophosphates; the other intermediates of glycolysis increased threeto eightfold. Fructose-2,6-bisphosphate was barely detectable in aged disks of transformed tubers. The relative rates of 14CO2 production from [1-14C]-and [6-14C]-glucose supplied to disks of transformed and control tubers were similar. Oxygen uptake and CO2 production by aged disks of transformed tubers did not differ significantly from those from control tubers. The same was true of CO2 production, in air, and in nitrogen, for tuber tissue. It is concluded that PFK(ATP) does not dominate the control of respiration in potato tubers.Abbreviations Fru2,6bisP
fructose-2,6-bisphosphate
- FW
freshweight
- GUS
-glucuronidase
- PFK(ATP)
6-phosphofructokinase
- PFK(PPi)
pyrophosphate: fructose-6-phosphate 1-phosphotransferase 相似文献
39.
White grubs (larval scarabaeids) are now recognized as being important pests of groundnut (peanut) in many parts of the world
because of their ability to damage roots. A method of simulating white grub damage to groundnut plants was developed to obtain
an indication of how the feeding activity of these insects influences plant growth. The effect of root cutting and drought
stress on water uptake and biomass production was evaluated, with roots being cut at three depths in the late vegetative and
early podfilling stages. As groundnut plants are often grown under conditions of drought stress, the effects of which would
be accentuated by root damage, this factor was introduced into the experiment. Plant water-use measurements indicated that
the root systems of plants cut 30 days after emergence (DAE) and watered twice a week became fully functional again after
40 days. Pod and total biomass production were however significantly less than those of the uncut control plants, with drought
stress reducing yields below the well-watered controls, particularly when cut at 10 cm below the soil surface. The root systems
of plants cut 51 DAE did not regrow to any appreciable extent, and rates of plant water-use remained less than half of the
uncut control plants. Over all treatments, there was a strong positive correlation between total (and pod) biomass and plant
water-use. It was concluded that the phenological stage of the plant at which root damage occurred had a profound influence
on the subsequent recovery in root growth and function, and ultimately on pod yield. 相似文献
40.
Photosynthetic characteristics of transgenic tobacco (Nicotiana tabacum L.) plants with a soluble pyrophosphatase in the cytosol of their leaf cells were compared to those of wild-type plants. Although the development of the transgenic plants was somewhat retarded compared to the wild type, as shown by stunted growth and delayed flowering, photosynthetic responses were comparable in transgenic and wild-type leaves of similar physiological age. In particular, light-dependent proton transport into the vacuoles of leaf mesophyll cells was not decreased in leaves of the transgenic plants, which did not contain pyrophosphate in the cytosol owing to the presence of a soluble pyrophosphase. This shows that light-stimulated proton pumping did not require the pumping activity of the tonoplast pyrophosphatase. Apparently, light-stimulated proton pumping can be based solely on the activity of the tonoplast ATPase.Abbreviation CDCF
5-(and 6-)arboxy-2,7-dichlorofluorescein
This work was supported within the Sonderforschungsbereiche 176 and 251 of the University of Würzburg. 相似文献