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51.
MODE OF NUCLEAR DIVISION IN SYNCHRONOUS CULTURES OF CHLORELLA: COMPARISON OF VARIOUS METHODS OF SYNCHRONIZATION 总被引:1,自引:0,他引:1
TAMIYA HIROSHI; MORIMURA YUJI; YOKOTA MIZUE; KUNIEDA REIKO 《Plant & cell physiology》1961,2(4):383-403
- Chlorella ellipsoidea was grown synchronously using variouspossible techniques and the mode of nuclear division in eachcase was followed by staining the nuclei according to FEULGEN.
- A satisfactory synchrony in respect to nuclear and cellulardivision was obtained by starting the culture from a homogeneouspopulation of young and small cells and by discontinuing theillumination at the stage which was called the L3-stage. Thestarting young cells were invariably mononuclear and the L3-cellswere either dinuclear or tetranuclear. When the L3 were incubatedin the dark, they ripened further, and after passing througha tetranuclear stage (referred to as the L4) divided into fourmononuclear daughter cells which have been called the Dn-cells.The most clear-cut and repetitive synchronous culture was obtainedwhen the culture (in the light) was started from the Dn-cellsand the illumination was discontinued at the L3-stage untilthe fully ripened cells divided into four each of Dn-cells.
- An apparently "synchronous" culture was also obtained by themethod of programmed light-and-dark regimen, in which a randomculture is subjected to a regular alternation of light and darkperiods of adequate durations. In this case, however, the cellsat different stages of culture showed irregular nuclear patterns,and the average "division number" of mother cells was not constant,being subject to change between 4.0 and 4.9.
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HIROSHI IKEDA HIDEAKI OHBA F.L.S. 《Botanical journal of the Linnean Society. Linnean Society of London》1993,112(2):159-186
IKEDA, H. & OHBA, H., 1993. A systematic revision of Potentilla lineata and allied species (Rosaceae) in the Himalaya and adjacent regions . Potentilla lineata and allied species (Rosaceae) in the Himalaya and adjacent regions are revised. Potentilla festiva Soják, P. josephiana H. Ikeda & H. Ohba, P. lineata Trev., P. fallens Card, and P. polyphylla Wall, ex Lehm. are recognized. Potentilla josephiana is a new name for P.fulgens Wall, ex Hook. var. intermedia Hook. f. Four varieties are recognized in P. polyphylla: var. polyphylla; var. himalaka H. Ikeda & H. Ohba, var. nov.; var. interrupta (Yü & Li) H. Ikeda & H. Ohba, stat. & comb, nov.; and var. barbata Lehm. A polyploid series is found in this group. Four putative hybrids between the species are also recognized. 相似文献
54.
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
55.
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
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MINORU SASAKI TOSHIO HORIKOSHI HIDEYO UCHIWA YOSHIKI MIYACHI 《Pigment cell & melanoma research》2000,13(4):248-252
Ultraviolet light (UV) radiation causes skin‐tanning, which is thought to be mediated by stimulating the release of melanogenic factors from keratinocytes as well as other cells. Nitric oxide (NO) has been reported to be generated after UV radiation and to stimulate melanocytes as one of the melanogens. In a previous experiment by another group on melanogenesis induced by NO, increases in both tyrosinase activity and tyrosinase protein levels were observed after daily stimulation of NO for 4 days. In the present study, we investigated tyrosinase gene expression within the first 24 hr of NO‐induced melanogenesis. Tyrosinase mRNA expression was found to be induced 2 hr after a single treatment with S‐nitroso‐N‐acetyl‐ l ‐arginine. An increase of tyrosinase activity was also detected time‐dependently within the 24‐hr period, accompanied by an increase of tyrosinase protein levels. The induction of mRNA expression was suppressed by a cyclic guanosine 3′,5′‐monophosphate (cGMP)‐dependent protein kinase (cGMP/PKG) inhibitor. These results suggest that the enhancement of tyrosinase gene expression via the cGMP pathway may be a primary mechanism for NO‐induced melanogenesis. 相似文献