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1.
D. Haferburg R. Hommel H.-P. Kleber S. Kluge G. Schuster H.-J. Zschiegner 《Engineering in Life Science》1987,7(4):353-356
A rhamnolipid released by Pseudomonas aeruginosa 196 Aa into the culture medium reduced the number of local lesions induced by tobacco mosaic virus on leaves of the hypersensitive host Nicotiana glutinosa L. by up to 90%. The content of potato virus X in the systemically infected host Nicotiana tabacum L. ‘Samsun’ is decreased in inoculated as well as in secondarily infected leaves by up to 50%. In a smaller degree red clover mottle virus is influenced in the systemic host Pisum sativumconvar.speciosum (Dierb.) Alef ‘Nadja’. 相似文献
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Rates of mutation to growth factor autonomy and tumorigenicity differ in hematopoietic stem and precursor cells expressing the multilineage colony-stimulating factor gene. 总被引:2,自引:0,他引:2 下载免费PDF全文
C Laker N Kluge C Stocking U Just M J Franz W Ostertag J F DeLamarter M Dexter E Spooncer 《Molecular and cellular biology》1989,9(12):5746-5749
At least two separate but interdependent events are required to attain autonomous growth as a consequence of ectopic expression of the multilineage colony-stimulating factor gene in hematopoietic progenitor cells. The rate at which the second event occurs is more than 3 orders of magnitude higher in precursor cell lines (FDC-P1 or FDC-P2) than in stem cell lines (FDC-Pmix). Autonomous, but not density-dependent, growth is tightly coupled to tumorigenicity in precursor cells; however, neither growth-factor-independent nor autonomously growing stem cell lines are tumorigenic. 相似文献
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Temperature effects on malic-acid efflux from the vacuoles and on the carboxylation pathways in crassulacean-acid-metabolism plants 总被引:5,自引:0,他引:5
The studies described in the paper were conducted with tissue slices of Crassulacean acid metabolism (CAM) plants floating in isotonic buffer. In a first series of experiments, temperature effects on the efflux of [14C]malate and14CO2 were studied. An increase of temperature increased the efflux from the tissue in a non-linear manner. The efflux was markedly influenced also by the temperatures applied during the pretreatment. The rates of label export in response to the temperature and the relative contributions of14CO2 and [14C]malate to the label export were different in the two studied CAM plants (Kalanchoë daigremontiana, Sempervivum montanum). In further experiments, temperature response of the labelling patterns produced by14CO2 fixation and light and darkness were studied. In tissue which had accumulated malate (acidified state) an increase of temperature decreased the rates of dark CO2 fixation whilst the rates of CO2 fixation in light remained largely unaffected. An increase of temperature shifted the labelling patterns from a C4-type (malate being the mainly labelled compound) into a C3-type (label in carbohydrates). No such shift in the labelling patterns could be observed in the tissue which had depleted the previously stored malate (deacidified state). The results indicate that in the acidified tissue the increase of temperature increases the efflux of malate from the vacuole by changing the properties of the tonoplast. It is assumed that the increased export of malic acid lowers the in-vivo activity of phosphoenol pyruvate carboxylase by feedback inhibition.Abbreviations CAM
Crassulacean acid metabolism
- FW
fresh weight
- PEPCase
phosphoenolpyruvate carboxylase
Dedicated to Professor O.L. Lange, Würzburg, on the occasion of his 60th birthday 相似文献
6.
Phyllodia of the Crassulacean acid metabolism (CAM) plant Kalanchoë tubiflora were allowed to fix 13CO2 in light and darkness during phase IV of the diurnal CAM cycle, and during prolongation of the regular light period. After 13CO2 fixation in darkness, only singly labelled [13C]malate molecules were found. Fixation of 13CO2 under illumination, however, produced singly labelled malate as well as malate molecules which carried label in two, three or four carbon atoms. When the irradiance during 13CO2 fixation was increased, the proportion of singly labelled malate decreased in favour of plurally labelled malate. The irradiance, however, did not change either the ratio of labelled to unlabelled malate molecules found in the tissue after the 13CO2 application, or the magnitude of malate accumulation during the treatment with label. The ability of the tissue to store malate and the labelling pattern changed throughout the duration of the prolonged light period. The results indicate that malate synthesis by CAM plants in light can proceed via a pathway containing two carboxylation steps, namely ribulose-1,5-bisphosphate-carboxylase/oxygenase (EC 4.1.1.39) and phosphoenolpyruvate carboxylase (EC 4.1.1.31) which operate in series and share common intermediates. It can be concluded that, in light, phosphoenolpyruvate carboxylase can also synthesize malate independently of the proceeding carboxylation step by ribulose-1,5-bisphosphate carboxylase/oxygenase.Abbreviations CAM
Crassulacean acid metabolism
- PEP
phosphoenolpyruvate
- PEPCase
phosphoenolpyruvate carboxylase (EC 4.1.1.31)
- RuBPCase
ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39)
- TMS
trimethylsilyl 相似文献
7.
Manfred Kluge 《Planta》1967,73(1):50-61
Summary Sieve tube sap obtained from cucumber plants infected by Cucumis Virus 2 A induced the typical mosaic disease when it was inoculated into healthy plants of the same species. The infectious factor could not be removed by dialysis or by treatment with phosphodiesterase. Therefore it is improbable that the virus is transported in the sieve tubes as low molecular units or as an unprotected RNA. Rod shaped particles (345×23 m) were found in the infectious sieve tube sap when it was investigated by electron microscopy. The same particles could be found in the sap extracted from infected leaves, but never in sieve tube sap obtained from healthy plants. There is reason to suppose that the Cucumis Virus 2 A is transported in the sieve tubes as complete particles.
Einige Ergebnisse dieser Arbeit sind Teil einer Dissertation der Technischen Hochschule Darmstadt (D 17, 1964). 相似文献
Einige Ergebnisse dieser Arbeit sind Teil einer Dissertation der Technischen Hochschule Darmstadt (D 17, 1964). 相似文献
8.
Summary Phagocytosis ofNostoc filaments byGeosiphon, a fungus closely related to AM forming Glomales, was observed under light microscopes. Incorporation can only be performed ifNostoc primordia come into contact with growing hyphal tips of the fungus. The fungal wall just below the apex softens, and fungal cytoplasm is bulged out repeatedly covering the vegetativeNostoc cells but not the heterocytes. New heterocytes are differentiated by the internalised filament whose cells can increase up to ten times in volume after recovering from incorporation strain. TheNostoc cells are coated stepwise by short finger-shaped protuberances of the fungal hypha. These hernia-like outgrowths first remain separated, after 1 to 2 days they merge. Adjacent hyphal walls inside the complex covering disintegrate. Periphal fungal wall portions are united to form a smooth strong outer envelope. Internalisation is categorised as phagocytosis. The partnership is partly specific,Nostoc strains capable of living endocytobiotically are often partners in other symbioses besidesGeosiphon.Abbreviations AM
arbuscular mycorrhiza (formerly VAM vesicular arbuscular mycorrhiza)
- DIC
differential interference contrast
- LD
light/dark
Dedicated to Prof. Dr. Dr. h.c. Eberhard Schnepf on the occasion of his retirement 相似文献
9.
Subunit c of the F1F0-ATPase from Propionigenium modestum was extracted from the particulate cell fraction with chloroform/methanol. The protein was further purified by carboxymethyl cellulose chromatography and anion exchange HPLC in the organic solvent. SDS-PAGE of the purified protein indicated a single stained protein band migrating as expected for the c-subunit. Incubation of isolated subunit c in chlorform/methanol or aqueous buffer containing dodecyl-β-
-maltoside with [14C]dicyclohexylcarbodiimide (DCCD) resulted in the incorporation of radioactivity into the protein. The rate of this reaction depended on the external pH; it was significantly faster in the more acidic than in the alkaline pH range. In the presence of Na+ subunit c was partially protected from labeling with [14C]DCCD at pH 6.1 and at pH 7.5, whereas no protection was evident at pH 5.5. At pH 7.5, the rate of subunit c labeling by [14C]DCCD in the presence of 20 mM NaCl was about 50% lower than in the absence of Na+ ions. The isolated c-subunit therefore apparently retains in part the Na+ binding site which, when occupied, diminishes the reactivity of the protein towards DCCD. 相似文献
10.