全文获取类型
收费全文 | 397篇 |
免费 | 12篇 |
国内免费 | 5篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 11篇 |
2015年 | 5篇 |
2014年 | 17篇 |
2013年 | 12篇 |
2012年 | 12篇 |
2011年 | 20篇 |
2010年 | 8篇 |
2009年 | 14篇 |
2008年 | 20篇 |
2007年 | 11篇 |
2006年 | 19篇 |
2005年 | 11篇 |
2004年 | 11篇 |
2003年 | 3篇 |
2002年 | 10篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 7篇 |
1994年 | 16篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 10篇 |
1990年 | 13篇 |
1989年 | 9篇 |
1988年 | 20篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 7篇 |
1984年 | 16篇 |
1983年 | 8篇 |
1982年 | 11篇 |
1981年 | 8篇 |
1980年 | 8篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1973年 | 1篇 |
排序方式: 共有414条查询结果,搜索用时 15 毫秒
411.
Prior research suggested that the genes for large (L) and small (S) subunits of ribulose bisphosphate carboxylase/oxygenase (RuBisCO) are amplified in ampicillin-resistant pBR322-transformants of Anacystis nidulans 6301. We now report that chromosomal DNA from either untransformed or transformed A. nidulans cells hybridizes with nick-translated [32P]-pBR322 at moderately high stringency. Moreover, nick-translated [32-P]-pCS75, which is a pUC9 derivative containing a PstI insert with L and S subunit genes (for RuBisCO) from A. nidulans, hybridizes at very high stringency with restriction fragments from chromosomal DNA of untransformed and transformed cells as does the 32P-labeled PstI fragment itself. The hybridization patterns suggest the creation of two EcoRI sites in the transformant chromosome by recombination. In pBR322-transformants the RuBisCO activity is elevated 6- to 12-fold in comparison with that of untransformed cells. In spite of the difference in RuBisCO activity, pBR322-transformants grow in the presence of ampicillin at a similar initial rate to that for wild-type cells. Growth characteristics and RuBisCO content during culture in the presence or absence of ampicillin suggest that pBR322-transformants of A. nidulans 6301 are stable. The data also collectively suggest that a given plasmid in the transformed population replicates via a pathway involving recombination between the plasmid and the chromosome. 相似文献
412.
Photosynthetic responses of citrus trees to soil flooding 总被引:1,自引:0,他引:1
Continuous soil flooding reduced leaf photosynthetic rate, stomatal conductance to water vapor, chlorophyll concentration and activity of ribulose bisphosphate carboxylase-oxygenase (Rubisco, EC 4.1.1.39) of sweet orange [ Citrus sinensis (L.) Osbeck cv. Hamlin] trees, grafted onto rough lemon (RL; C. jambhiri Lush.) and sour orange (SO; C. aurantium L.) rootstocks. After 24 days of waterlogging, trees showed senescence, wilting and abscission of leaves, and these symptoms were more evident with flooded Hamlin/SO than Hamlin/RL. Reduction of leaf photosynthetic rate at day 24 was ca 94%, of stomatal conductance, 71%, of chlorophyll, 38% and of Rubisco, 62% for flooded Hamlin/SO, compared with 22, 5, 18 and 33%, respectively, for flooded Hamlin/RL. For both Hamlin/RL and Hamlin/SO, leaf photosynthetic rate and stomatal conductance to water vapor were closely correlated (r2 = 0.87). Leaf internal CO2 concentration of flooded trees, however, was not decreased by reduced stomatal conductance. Dark respiration rates of fibrous roots of flooded trees were greatly reduced, but not in leaf tissues. Total nonstructural carbohydrate concentrations were higher in leaves (50 and 80% increases for Hamlin/SO and Hamlin/RL, respectively), but drastically reduced in roots (60 and 45% reductions for Hamlin/SO and Hamlin/RL, respectively), as a result of flooding. The data indicate that Hamlin grafted onto RL rootstocks was more tolerant to soil flooding than Hamlin grafted onto SO rootstocks. 相似文献
413.
1. Turnover of the photosynthetic carbon reduction cycle has been demon-strated in chlorophyll-free reaction mixtures containing chloroplast stromal extract, as evidenced by the fixation of CO2 following addition of small amounts of 3-phosphoglycerate.2. The activity of the photosynthetic carbon reduction cycle in this system is inhibited by inorganic phosphate (Pi), with activity reduced to 50% by about 6.5 mM Pi. Pi also increased the lag period which elapsed before a steady rate of CO2 fixation was obtained.3. The effect of Pi on the rate of 3-phosphoglycerate reduction following the addition of substrate amounts of some cycle intermediates was investigated. Substantial inhibition was observed with fructose 1,6-bisphosphate, sedoheptulose 1,7-bisphosphate and erythrose 4-phosphate as substrates. Pi also affected the activity of ribulose-bisphosphate carboxylase, with stimulation at Pi concentrations below 2.5 mM and inhibition at higher concentrations.4. The results showed that the sedoheptulose bisphosphatase reaction is inhibited more strongly by Pi than the fructose bisphosphatase reaction.5. It is concluded that the previously established inhibitory effects of Pi on photosynthesis by intact isolated chloroplasts may be partly due to these inhibitory effects of Pi on the reactions of the photosynthetic carbon reduction cycle. 相似文献
414.