全文获取类型
收费全文 | 118篇 |
免费 | 5篇 |
出版年
2020年 | 2篇 |
2018年 | 3篇 |
2014年 | 1篇 |
2013年 | 1篇 |
2012年 | 4篇 |
2011年 | 2篇 |
2010年 | 5篇 |
2009年 | 4篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 6篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 6篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 4篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1964年 | 1篇 |
1959年 | 1篇 |
1958年 | 4篇 |
1957年 | 3篇 |
1956年 | 1篇 |
1955年 | 6篇 |
1953年 | 1篇 |
排序方式: 共有123条查询结果,搜索用时 796 毫秒
1.
YUDAI OKUYAMA MAKOTO KATO NORIAKI MURAKAMI 《Botanical journal of the Linnean Society. Linnean Society of London》2004,144(4):449-460
The first example of pollination by fungus gnats in the eudicots is reported. The genus Mitella (Saxifragales) is characteristically produces minute, inconspicuous, mostly dull-coloured flowers with linear, sometimes pinnately branched, petals. To understand the function of these characteristic flowers, we studied the pollination biology of four Mitella species with different floral traits and different sexual expression: dioecious M. acerina , gynodioecious M. furusei var. subramosa , and hermaphroditic M. stylosa var. makinoi and M. integripetala. Flower-bagging experiments showed that wind pollination did not occur in the dioecious and gynodioecious species. Two years of observations of flower visitors at six study sites in Japan revealed that the principal pollinators of all four Mitella were specific species of fungus gnats (Mycetophilidae), which landed on the flowers with their long spiny legs settling on the petals. Characteristically, numerous pollen grains were attached to the fungus gnats in specific locations on the body. Although, on average, 1.3–2.6 fungus gnats visited each inflorescence per day, the fruit set of both bisexual and female flowers exceeded 63%. These results suggest that fungus gnats are highly efficient pollinators of Mitella spp., and that Mitella flowers are morphologically adapted to pollination by fungus gnats. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 449–460. 相似文献
2.
SHOKO YASUKAWA HIDETOSHI KATO RYOHEI YAMAOKA HAJIME TANAKA HIROHITO ARAI SHOICHI KAWANO 《Plant Species Biology》1992,7(2-3):121-140
Abstract Volatile substances emitted from the flowers of eight Magnolia taxa ( M. sieboldii ssp. japonica, M. praecocissima var. praecocissima and var. borealis, M. tomentosa, M. salicifolia, M. obovata, M. denudata, and M. grandiflora ) and one Michelia species ( M. compressa ) (Magnoliaceae) were examined and identified using GC-MS. Volatile substances of these Magnolia and Michelia species consist primarily of monoterpenoids and sesquiterpenoids produced by the mevalonate pathway, acetogenins by the acetate-malonate pathway, and phenyl-propanoids by the shikimate pathway. These Magnolia and Michelia species all possessed various combinations of volatile monoterpenoids, acetogenins, and phenylpropanoids, except for Magnolia obovata , which emitted primarily sesquiterpenoids. Free amino acids in pollen of 12 Magnolia and one Liriodendron species were also analyzed, and their value as food sources for pollinators evaluated.
Pollinators visiting the flowers of five Magnolia species were collected in their native sites and identified. Their behaviors and roles as pollinating agents were assessed. 相似文献
Pollinators visiting the flowers of five Magnolia species were collected in their native sites and identified. Their behaviors and roles as pollinating agents were assessed. 相似文献
3.
SHIGENOBU TONÉ SHOJI TANAKA YOSHIHIRO KATO 《Development, growth & differentiation》1988,30(3):261-270
The cell cycle and cell population kinetics have been analyzed in the interdigital regions of chick limb-buds during the course of programmed cell death both in normal and the 5-bromodeoxyuridine (BrdU)-treated embryos. Our previous study has shown that a single administration of BrdU at day 6 1/3 inhibited the programmed cell death occurring in normal development of limb-buds.
Pulse- as well as continuous labelings with tritiated thymidine (3 H-TdR) were used. The results obtained from the analyses made on both normal and experimental embryos have demonstrated the presence of a particular DNA-synthetic period, around day 6 1/3, closely related to the programmed death occurring on day 7 1/3. In normal embryos, new cell populations, which did not belong to any phases of normal cell cycle, made their appearances in the process of programmed cell death. A possible correlation between programmed cell death and the cell cycle has been discussed in relation to the morphogenesis of limbs in both normal and BrdU-treated embryos. 相似文献
Pulse- as well as continuous labelings with tritiated thymidine (
4.
The society finch, a little passerin, was purposed to be utilized in embryological studies. Under control of the breeding cycle in 20 pairs, 4 to 6 eggs were used to be laid daily for several repeating week in a year. Average incubation time was 17 days in contrast to 21 in the domestic fowl. The eggs weighed 1.1 g in average and expected smallness of the embryo was regarded as favorable for morphological studies including the scanning electron microscopy. We present the first report of the complete development of the society finch. A number of embryological characteristics are described with special reference to the peculiarity of the altricial finch as compared with the precocial domestic fowl. 相似文献
5.
YUJI MISHINA TAKASHI KATO AKIO URABE FUMIMARO TAKAKU SHUNJI NATORI MASUO OBINATA 《Development, growth & differentiation》1986,28(1):1-6
Erythroid cells were fractionated by preformed Percoll density gradient from livers of 12.5 day old mouse fetuses. With combination of lysing of mature erythroid cells, the CFU-E (colony forming unit of erythroid) was enriched as high as 30% pure. The mRNA levels of the rt-genes previously cloned as genes expressed in the reticulocytes are estimated in the fractionated erythroid cells. These rt-genes show a drastic change in expression during erythroid differentiation; Their expression was not detectable at the CFU-E cell stage. But it reached to maximum at the polychromatic erythroblast (stage I) and then decreases with maturation. The result suggests that mRNA synthesis of these rt-genes may be induced after the stimulation of erythropoietin. 相似文献
6.
MASAHIRO SATO SHUN-ICHIROH OGATA RYUZO UEDA REIKO NAMIKAWA TOSHITADA TAKAHASHI TAKAO NAKAMURA EIICHI SATO TAKASHI MURAMATSU 《Development, growth & differentiation》1983,25(4):333-344
C-9-1, a monoclonal IgM antibody raised against human null cell acute lymphocytic leukemia cells reacted with restricted regions of embryonic and adult tissues of the mouse. The antigen positive sites in the embryos included embryonic ectoderm, visceral endoderm, trophoblastic cells invading the maternal decidua of 5∼7-day embryos, primordial germ cells of 10∼12-day embryos, epithelium of nasal chamber, the bronchus, Mullerian duct, epididymis and bladder of 12∼17-day embryos. In the adult mice, C-9-1 antigen was detected in renal tubules, a part of stomach, bladder, endometrium and epididymal sperm. Embryonal carcinoma cells, but not endodermal cells of teratocarcinoma expressed the antigen. Thus, C-9-1 antigen showed distribution similar to SSEA-1. However, C-9-1 antigen was not detected in preimplantation embryos, nor in oviduct, both of which are positive for SSEA-1. 相似文献
7.
MATSUDA YOSHIHIRO; KIKUCHI TADATOSHI; ISHIDA MASAHIRO R. 《Plant & cell physiology》1971,12(1):127-135
When dark grown cells of Chlamydomonas reinhardtii y-1 mutantwere exposed to continuous light, an immediate transformationof small amounts of protochlorophyll(ide), which had been presentin the dark grown cells, to chlorophyll was observed. Afterthis, there was a slow accumulation of chlorophyll lasting for2.5-3 hr before the start of exponential synthesis. Initialaccumulation of chlorophyll was distinctly slower at a highlight intensity (13,000 lux) than it was at moderate intensitiesof light (2,0005,000 lux). However, the exponential synthesisof chlorophyll started after the same 2.53 hr of illumination. A brief pre-illumination of cells followed by incubation indarkness was effective in promoting chlorophyll synthesis undersubsequent continuous illumination at high, as well as moderatelight intensities. Pretreatment alleviated retardation of theinitial chlorophyll accumulation by light of high intensity.The promoting effect of preillumination on chlorophyll synthesiswas sufficient, even when a light impulse as short as 10 secwas given. However, the effect was dependent on length of thedark period after the short pre-illumination. The full extentof this effect was observed when the dark period was about 2.53hr long. Further dark incubation gradually decreased the effect. On the basis of these findings, it is assumed that a factor(s)responsible for promotion of chlorophyll (or chloroplast) synthesisin the process of greening of dark grown cells is produced duringthe dark period after a brief pre-illumination, and that thefactor is turned over at a relatively fast rate. The possiblenature of the presumed factor is discussed in relation to chloroplastdevelopment.
1Present address: Department of Biology, Faculty of Science,Kobe University, Nada-ku, Kobe, Japan. (Received August 18, 1970; ) 相似文献
8.
KAMEMOTO FRED I.; KATO KENNETH N.; TUCKER LOIS E. 《Integrative and comparative biology》1966,6(2):213-219
The possible role of the neurosecretory system in regulationof salt and water has been studied in the annelids and crustaceans.In the earthworm, Lumbricus terrestris, a brain factor influences'the salt and osmotic concentration of the blood and coelomicfluid. Removal of the brain results in the increase of waterinflux with a decrease in the salt and osmotic concentrationsof the body fluids. The decreases in salt and osmotic concentrationscan be prevented by the implantation of the brain or the injectionof brain homogenates. In the freshwater crayfish, Procambarus clarkii, a factor, presumablysecreted in the brain and released in the eyestalk, seems tomaintain the normal permeability of the body surfaces to water.Eyestalk removal, which eliminates the release site, resultsin the increased influx of water with a decrease in the saltconcentration of the blood. A brain factor also seems to beinvolved in maintaining the sodium and osmotic concentrationsof the blood. In the semi-terrestrial grapsid crab, Metopograpsus messor,the thoracic ganglion, under the control of an eyestalk element,secretes a factor involved in increasing the permeability ofthe body surfaces to water. The removal of the eyestalks, theimplantation of the thoracic ganglion, or the injection of extractsof thoracic ganglia, results in changes in the osmotic concentrationof the blood tending toward that of the medium. In all threespecies studied, the neuroendocrine factors seem to be involvedprimarily in the regulation of the permeability of the bodysurfaces to water. 相似文献
9.
KOUKI ONO MASAHIRO OKIHASHI HIROSHI INUI KAZUTAKA MIYATAKE SHOZABURO KITAOKA YOSHIHISA NAKANO 《The Journal of eukaryotic microbiology》1994,41(6):536-539
Isocitrate lyase was purified to homogeneity from ethanol-grown Euglena gracilis. The specific activity was 0.26 μmol/min/mg protein. The molecular mass of the enzyme was calculated to be 380 kDa by gel filtration on a Superose 6 column. The subunit molecular mass of the enzyme was 116 kDa as determined by SDS-polyacrylamide gel electrophoresis. These results showed that the native form of this enzyme was a trimer composed of three identical subunits. The pH optimum for cleavage and condensation reactions was 6.5 and 7.0, respectively. The Km values for isocitrate, glyoxylate and succinate were 3.8, 1.3 and 7.7 mM, respectively. Isocitrate lyase absolutely required Mg for enzymatic activity. This is the first report of the purification of isocitrate lyase to homogeneity from Euglena gracilis. 相似文献
10.
A strain of carrot cells (Daucus carota cv. Kintoki) grew exponentially in the presence of 2,4-dichlorophenoxyacetic acid (2,4-D, 1 mg/1) with a doubling time of about 2 days. When those cells were transferred to a medium lacking 2,4-D, they continued to grow at almost the same rate for about a week. When the cells were again transferred to the auxin-free medium, the rate of cell division gradually decreased. After the cell division had ceased, cells were returned to the ordinary 2,4-D medium. A burst of cell divisions occurred after about 2 days. Timing of DNA synthesis and of mitosis suggested that the cells had been arrested at G1 phase. In a medium containing indoleacetic acid instead of 2,4-D, the auxin was rapidly degraded and the culture was similarly synchronized as in the auxin-omitted medium. 相似文献