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121.
Although touch responses of plant roots are an important adaptive behavior, the molecular mechanism remains unclear. We have
developed a bioassay for measuring root-bending responses to physical hardness in Arabidopsis thaliana seedlings. Our test requires a two-layer solid medium. Primary roots growing downward through an upper layer of 0.3% phytagel
either penetrate the lower layer or bend along an interface between the upper and lower layers with different concentrations
(0.2–0.5%, corresponding to 1.57–6.79 gw mm−2 in hardness). In proportion to increasing hardness of the lower layer, we found that the percentage of bending roots increased
and ethylene production decreased, suggesting an inverse relationship between the root-bending response and ethylene production.
Studies with ethylene biosynthesis modulators and mutants also suggested that bending and non-bending responses of roots to
medium hardness depend, respectively, on decreased and increased ethylene biosynthesis. In addition, the degrees of root-tip
softening and differential root-cell growth, both possible factors determining root-bending response, were enhanced and attenuated
by decreased and increased amounts of ethylene, respectively—also in bending roots and non-bending roots. Our findings indicate
that ethylene regulates root touch responses, probably through a combination of root-tip softening (or hardening) and differential
root-cell growth. 相似文献
122.
The structure of a novel aromatic compound contained in the unidentified Rhizoglyhus mite (Acaridae: Astigmata) was elucidated, without its isolation, to be 3-hydroxybenzene-1,2-dicarbaldehyde (tentatively named gamma-acaridial) by a combination of GC/MS and GC/FT-IR together with knowledge of related mite compounds. The structure was confirmed by a 5-step synthesis, starting from methyl 3-hydroxybenzoate, in a 15% overall yield. The compound is widely distributed not only among Astigmata but also among Oribatida, although its biological function is obscure at present. 相似文献
123.
Analysis of Petal Anthocyanins to Investigate Flower Coloration of Zhongyuan (Chinese) and Daikon Island (Japanese) Tree Peony Cultivars 总被引:14,自引:0,他引:14
Liang-Sheng Wang Aya Shiraishi Fumio Hashimoto Noriaki Aoki Keiichi Shimizu Yusuke Sakata 《Journal of plant research》2001,114(1):33-43
Pn, Pg; Pn, Pg > Cy ; Pn, Cy and Pn, Cy > Pg groups. Each group consequently specified significant features among CIELAB color notation and petal pigmentation, being
adequate to characterize tree peony flowers as similar between Zhongyuan and Daikon Island cultivars, thus the cultivars of
the two areas are suggested to be related to one another.
Received 25 April 2000/ Accepted in revised form 21 December 2000 相似文献
124.
Protective Effect of External Ca2+ on Elongation and the Intracellular Concentration of K+ in Intact Mung Bean Roots under High NaCl Stress 总被引:2,自引:0,他引:2
Nakamura Yoshiyuki; Tanaka Karo; Ohta Eiji; Sakata Makoto 《Plant & cell physiology》1990,31(6):815-821
The effects of Ca2+ in the external medium on intact mung beanroots under high NaCl stress were investigated. With increasingexternal concentrations of NaCl, mung bean roots showed suppressionof elongation and a decrease in the intracellular concentrationof K+. Addition of Ca2+ to the external medium alleviated theinhibition of root elongation under the high NaCl stress andmaintained a high intracellular concentration of K+ in the elongatingregion of the roots. This counter effect of Ca2+ against theNaCl stress on roots was correlated with the ratio of [Ca2+]/[Na+]2in the external medium. A value above 5.0 ? 104 mM1resulted in almost complete recovery of root elongation undervarious high concentrations of NaCl. Root elongation for 24h under NaCl stress was correlated with the extent to whichthe intracellular concentration of K+ was in excess of 10 mM.Maintenance of an adequate concentration of K+ in root cellsis essential for root elongation under salt stress. These findingsindicate that Ca2+ prevents the leakage of intracellular K+and thereby supports the elongation of roots under salt stress. (Received November 13, 1989; Accepted June 5, 1990) 相似文献
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127.
RIP1 is a serine/threonine kinase, which is involved in apoptosis and necroptosis. In apoptosis, caspase-8 and FADD have an important role. On the other hand, RIP3 is a key molecule in necroptosis. Recently, we reported that eleostearic acid (ESA) elicits caspase-3- and PARP-1-independent cell death, although ESA-treated cells mediate typical apoptotic morphology such as chromatin condensation, plasma membrane blebbing and apoptotic body formation. The activation of caspases, Bax and PARP-1, the cleavage of AIF and the phosphorylation of histone H2AX, all of which are characteristics of typical apoptosis, do not occur in ESA-treated cells. However, the underlying mechanism remains unclear. To clarify the signaling pathways in ESA-mediated apoptosis, we investigated the functions of RIP1, MEK, ERK, as well as AIF. Using an extensive study based on molecular biology, we identified the alternative role of RIP1 in ESA-mediated apoptosis. ESA mediates RIP1-dependent apoptosis in a kinase independent manner. ESA activates serine/threonine phosphatases such as calcineurin, which induces RIP1 dephosphorylation, thereby ERK pathway is activated. Consequently, localization of AIF and ERK in the nucleus, ROS generation and ATP reduction in mitochondria are induced to disrupt mitochondrial cristae, which leads to cell death. Necrostatin (Nec)-1 blocked MEK/ERK phosphorylation and ESA-mediated apoptosis. Nec-1 inactive form (Nec1i) also impaired ESA-mediated apoptosis. Nec1 blocked the interaction of MEK with ERK upon ESA stimulation. Together, these findings provide a new finding that ERK and kinase-independent RIP1 proteins are implicated in atypical ESA-mediated apoptosis. 相似文献
128.
Logan S. James Chihiro Mori Kazuhiro Wada Jon T. Sakata 《Current biology : CB》2021,31(13):2796-2808.e9
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129.
Twelve anthocyanins (1-12) were isolated from the red flowers of Camellia hongkongensis Seem. by chromatography using open columns. Their structures were elucidated on the basis of spectroscopic analyses, that is, proton-nuclear magnetic resonance, carbon 13-nuclear magnetic resonance, heteronuclear multiple quantum correlation, heteronuclear multiple bond correlation, high resolution electrospray ionization mass and ultraviolet visible spectroscopies. Out of these anthocyanins, a novel acylated anthocyanin, cyanidin 3-O-(6-O-(Z)-p-coumaroyl)-β-galactopyranoside (6), two known acylated anthocyanins, cyanidin 3-O-(6-O-(E)-p-coumaroyl)-β-galactopyranoside (7) and cyanidin 3-O-(6-O-(E)-caffeoyl)-β-galactopyranoside (8), and three known delphinidin glycosides (10-12) were for the first time isolated from the genus Camellia. Furthermore, pigment components in C. japonica L., C. chekiangoleosa Hu and C. semiserrata Chi were studied.The results indicated that the distribution of anthocyanins was differed among these species. Delphinidin glycoside was only detected in the flowers of C. hongkongensis, which is a special and important species in the section Camellia. Based on the characterization of anthocyanins in the section Camellia species, there is a close relationship among these species,and C. hongkongensis might be an important parent for creating new cultivars with bluish flower color. 相似文献
130.
Yoshiki Sakata 《Bioscience, biotechnology, and biochemistry》2013,77(6):355-361
The velocity of the α-β transition was measured in two cases, i.e., when α-crystals stayed in the saturated aqueous solution, and when they were left to stand in an air-bath at various temperatures ranging from 20° to 100°C. And it was deduced from the results of the measurement that this transition is due to the recrystallization of α-crystals into the β-form on the inner surfaces of the crystal and in the bulk of the solution, and the transition on the inner surfaces will be dominant, especially at the initial stage of the transition. 相似文献