全文获取类型
收费全文 | 208篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
210篇 |
出版年
2014年 | 2篇 |
2011年 | 5篇 |
2010年 | 4篇 |
2009年 | 8篇 |
2008年 | 2篇 |
2007年 | 2篇 |
2006年 | 5篇 |
2005年 | 7篇 |
2004年 | 2篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 4篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 8篇 |
1995年 | 3篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1976年 | 6篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1971年 | 8篇 |
1970年 | 7篇 |
1969年 | 4篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 3篇 |
1965年 | 3篇 |
1964年 | 3篇 |
1963年 | 3篇 |
1961年 | 5篇 |
1960年 | 1篇 |
1958年 | 4篇 |
1957年 | 1篇 |
1956年 | 2篇 |
1954年 | 1篇 |
排序方式: 共有210条查询结果,搜索用时 15 毫秒
51.
Primary leaves of intact bean plants (Phaseolus vulgaris L.) were treated with benzyladenine (BA) at different stages during growth. Changes in DNase, RNase, and proteas activities in the leaves were followed. Unlike the case of various excised tissues, cytokinin raised the activities of these hydrolases in intact bean leaves. Because BA elevated the levels of DNA, RNA, and protein in intact leaves, it may stimulate both synthesis and decomposition of these cellular constituents. The hydrolase activities showed differential responses to BA according to the age at which the leaf received the hormone treatment. 相似文献
52.
SEIJI KAMIJO YUTAKA KAWAGUCHI HIROSHI FUJII BUNGO SAKAGUCHI HIROSHI DOIRA SATORU KUHARA YOICHI ASO KATSUMI KOGA KATSUYA HAYASHI KUNITADA SHIMOTOHNO 《Development, growth & differentiation》1978,20(4):283-289
The mucous glands of Bombyx pupae secrete glue proteins which attach deposited eggs to the mounting sheet. A mutant of a dominant gene, named no glue (Ng) , produces nonadhesive eggs which have a low capacity for glue-protein synthesis. In the present study it was shown that the mucous glands of Ng silkworms showed rapid degradation of mRNA as well as rRNA during development; this may cause the low capacity for glue-protein synthesis in the mutant organ. In contrast, the mucous glands of normal silkworms showed a significant increase in content of RNA's until the maximum rate of glue-protein synthesis was achieved. The degradation of RNA in the Ng mucous gland was inhibited by actinomycin D injected into the body fluid. Thus it is supposed that the Ng gene codes for a presumptive controller RNA, which would be the mediator of RNA instability in the mucous glands of Ng pupae. 相似文献
53.
Self or Non--self Recognition in Compound Ascidians 总被引:1,自引:0,他引:1
SYNOPSIS. Certain species of compound ascidians have an abilityto distinguish self colonies from nonself colonies withinthe same species. This ability, called colony specificity, ismanifested by the fusibility between colonies. The fusibilityamong colonies of Japanese Botryllus is genetically controlledby a series of multiple alleles at a single locus. The fusibilityis determined by a factor(s) in blood, so that the fusibilitycan be altered by the exchange of blood. It is suggested thatrejection, called "nonfusion" reaction, may occur from the interactionbetween blood cells and blood humoral factor(s). 相似文献
54.
55.
56.
57.
- Using the Chlorella cells which had been uniformly labeled with32P, the distribution of phosphorus in various fractions ofcell material was investigated. Uniformly 32P-labeled Chlorellawas further grown in a P-free medium or in a standard "cold"medium, and the change of distribution of 32P (as well as theuptake of exogenous P) in various cell fractions was followed.
- Analysis of the 32P-labeled algal cells showed that the highestin P-content was the fraction of RNA followed by those of polyphosphates,lipid, nucleotidic labile phosphate compounds, DNA and protein(in decreasing order). ATP and ADP were found to be only minorfractions of the total labile phosphates.
- On incubating the3P-labeled alga in a P-free medium, the P.contentsin the fractionsof DNA, protein, lipid and ATP increased, thosein polyphosphatesand ADP decreased, and that in RNA remainedalmost unchanged.When the 32P-labeled alga was further grownin the normal "cold"medium, DNA and protein increased withthe expenditure of endogenous32P, but with practically no incorporationof external P. Inthe meantime the P in polyphosphates decreasedconsiderably,and the RNA fraction incorporated a large amountof externalP but only a little of endogenous32P.
- It was inferred that,under the experimental conditions of thepresent study, thephosphorus used in the syntheses of DNA andprotein was primarilytaken from polyphosphates, while thatused in the synthesesof RNA, phospholipid and polyphosphateswas, for the most part,taken from the extracellular P-source.
58.
Nutrient utilization and requirement under photoheterotrophic growth of Marchantia polymorpha: Improvement of the culture medium 总被引:1,自引:0,他引:1
KENJI KATOH MOMOYO ISHIKAWA KEIKO MIYAKE YOSHIMOTO OHTA YOSHIO HIROSE TATSUICHI IWAMURA 《Physiologia plantarum》1980,49(2):241-247
Previously we reported on a suspension culture of chlorophyllous cells of a liverwort, Marchantia polymorpha L., under photoheterotrophic conditions. The chemically defined medium was a modified Murashige and Skoog's medium, which contained, besides glucose, inorganic salts, a growth regulator (2,4-D), and twenty-four organic compounds as micro constituents. Because of this complexity, we undertook a simplification of the medium. Having examined the utilization of the major nutrients and the requirements for the micro constituents, we have succeeded in improving the medium. The new medium contains phosphate at 3.13 mM and only eight out of the twenty-four original micro organic constituents. In this new medium, the cells grow under a well-balanced nutritional condition, with richer chlorophyll and at a higher rate during the exponential phase than in the original medium. 相似文献
59.
YUKITOSHI KIMOTO HIROSHI TOBE 《Botanical journal of the Linnean Society. Linnean Society of London》2008,158(2):228-241
We investigated the embryology of the ‘lower’ monimioids, i.e. Monimioideae (Monimia, Palmeria and Peumus) and Hortonioideae (Hortonia), which are poorly described embryologically. Our results show that, contrary to what has been reported in the literature, ‘lower’ monimioids show very little variation in their embryological characters. Comparisons with Mollinedioideae (a large derived subfamily in Monimiaceae) and other families in Laurales show that the ‘lower’ monimioids are relatively consistent in sharing predominantly isobilateral tetrads of microspores and megaspores, a non‐specialized chalaza, and a mesotestal–endotestal seed coat (with tracheoidal cells of the meso‐ and endotesta). It is likely that, while the shared successive cytokinesis during meiosis of microspore mother cells supports the Monimiaceae–Hernandiaceae–Lauraceae clade obtained by molecular evidence, no synapomorphies exist to support a sister‐group relationship of Monimiaceae with Hernandiaceae or Lauraceae. Instead, the lack of hypostase in ovules and/or young seeds, the lack of endosperm in mature seeds and the amoeboid tapetum in the anther are likely synapomorphies of Hernandiaceae and Lauraceae. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 228–241. 相似文献
60.
A new culture apparatus was constructed to obtain large quantitiesof synchronized cells of Chlorella ellipsoidea. Two flat culturechambers made of lucid acrylate resin (each 20 liters in capacity)were placed in a water thermostat together with a bank of 17daylight fluorescent lamps, and the culture was run by the methodstarting from a homogeneous population of Ds-cells accordingto TAMIYA et al. It was demonstrated that with this apparatusone can obtain as much as 200400 mg (dry weight) eachof algal material at 8 or 9 different stages in one cell cycle.Completely synchronized cell cycles could be repeated as manyas 10 times in one series of experiment, indicating that theapparatus can produce 24g (dry weight) each of algalcells of different developmental stages. (Received April 2, 1964; ) 相似文献