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排序方式: 共有238条查询结果,搜索用时 46 毫秒
81.
Thein vivo
14CO2 fixation assay and xylem sap analysis showed that inSesbania rostrata the transport of fixed nitrogen from stem nodules was in the amide form. The majority of nitrogen was transported as asparagine.
The close relationship between nodule phosphoenolpyruvate carboxylase and nitrogenase activities suggested that nodule CO2 fixation contributed directly to nitrogen assimilation in stem nodules ofS. rostrata. 相似文献
82.
Surfacing frequency (Sf) in obligatory air-breathing fishes is a behavioural index of O2 uptake; as both are interrelated, there is a possibility of predicting one from the other. From the point of cause and effect relationship, feeding (C) is regarded as the cause and Sf and O2 uptake as its effects. Hence, the last two are predictable from the cause. A pathway for predicting the bioenergetics components, feeding (C), metabolism (M) and growth (P) from a behavioural index of surfacing frequency has been proposed. In this model, C occupies the focal point connecting on the horizontal plane Sf on one side and P on the other side and M vertically. The developed multiple regression models predict the bioenergetics components of the fishes,Macropodus cupanus andChanna striatus of different weight classes ex-posed to different rations and temperatures; the percentage of variation accounted for by the equations is over 90. The pathway can also be followed for predicting bioenergetics components of gill-breathing fishes, if feeding rate alone is known. On application of the relevant part of the pathway toSalmo trutta, the percentage of variation accounted by the equations is 95. 相似文献
83.
Ploidy induction and sex control in fish 总被引:19,自引:0,他引:19
84.
A rapid and efficient method of lysis of Listeria and other gram-positive bacteria using mutanolysin. 总被引:4,自引:0,他引:4
A rapid and simple procedure is described for cell lysis for preparation of nucleic acids and intact ribosomal RNA from Gram-positive bacteria. Commercial mutanolysin (purified from Streptomyces globisporus) was used for inducing lysis. Listeria, Lactobacillus and Lactococcus strains were very sensitive to mutanolysin when compared to lysozyme. Susceptibility to mutanolysin was improved by a preliminary treatment with acetone, and sodium dodecyl sulfate reduced the efficiency of lysis when used together with mutanolysin. The procedure was also effective for recovering plasmids from these bacteria. 相似文献
85.
M R Pandian O P Bahl S J Segal 《Biochemical and biophysical research communications》1975,64(4):1199-1205
Human chorionic gonadotropin (hCG) was found to stimulate the incorporation of [14C] N-acetyl-D-glucosamine in rat ovary in vitro. Subcellular fractionation of the ovarian tissue revealed that the plasma membranes were stimulated maximally to the extent of 200 to 300% by the hormone indicating the stimulation of the synthesis of plasma membrane glycoproteins. In addition, and appreciable amount of the radioactivity was incorporated in the cell surface LH/hCG receptor. The evidence in support of the labeling of the receptor was derived from the behavior of the detergent solubilized receptor on Sepharose 6B column and on hCG-Sepharose affinity adsorbent. The labeled receptor thus purified showed binding affinity for [125I] hCG. Thus, the hormone stimulates the synthesis of cell surface glycoproteins as well as the LH/hCG receptor. 相似文献
86.
87.
88.
A Stable Graphitic,Nanocarbon‐Encapsulated,Cobalt‐Rich Core–Shell Electrocatalyst as an Oxygen Electrode in a Water Electrolyzer
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Arumugam Sivanantham Pandian Ganesan Luis Estevez B. Peter McGrail Radha Kishan Motkuri Sangaraju Shanmugam 《Liver Transplantation》2018,8(14)
The oxygen electrode plays a vital role in the successful commercialization of renewable energy technologies, such as fuel cells and water electrolyzers. In this study, the Prussian blue analogue‐derived nitrogen‐doped nanocarbon (NC) layer‐trapped, cobalt‐rich, core–shell nanostructured electrocatalysts (core–shell Co@NC) are reported. The electrode exhibits an improved oxygen evolution activity and stability compared to that of the commercial noble electrodes. The core–shell Co@NC‐loaded nickel foam exhibits a lower overpotential of 330 mV than that of IrO2 on nickel foam at 10 mA cm?2 and has a durability of over 400 h. The commercial Pt/C cathode‐assisted, core–shell Co@NC–anode water electrolyzer delivers 10 mA cm?2 at a cell voltage of 1.59 V, which is 70 mV lower than that of the IrO2–anode water electrolyzer. Over the long‐term chronopotentiometry durability testing, the IrO2–anode water electrolyzer shows a cell voltage loss of 230 mV (14%) at 95 h, but the loss of the core–shell Co@NC–anode electrolyzer is only 60 mV (4%) even after 350 h cell‐operation. The findings indicate that the Prussian blue analogue is a class of inorganic nanoporous materials that can be used to derive metal‐rich, core–shell electrocatalysts with enriched active centers. 相似文献
89.
Influence of Ammonium Salts and Cane Molasses on Growth of Alcaligenes eutrophus and Production of Polyhydroxybutyrate 总被引:1,自引:0,他引:1
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The production of polyhydroxybutyrate (PHB) by Alcaligenes eutrophus DSM 545 was studied in a synthetic medium with 3% glucose at pH 7.0 supplemented with several ammonium substrates and cane molasses. Growth was measured by dry cell weight, and the PHB content was measured by gas chromatography. The effects of ammonium sources such as sulfate, nitrate, phosphate, and chloride salts and those of different ammonium sulfate concentrations were evaluated. The best growth and PHB production were obtained with ammonium sulfate; however, NH(inf4)(sup+) concentrations between 0.5 and 1.5 g/liter showed no significant difference. Ammonium sulfate was therefore used as the sole source of NH(inf4)(sup+) for experiments with cane molasses as the growth activator. Optimal growth and PHB production were obtained with 0.3% molasses. However, the yields of biomass (39 to 48%) and PHB (17 to 26%) varied significantly among the different ammonium substrates and cane molasses concentrations. 相似文献
90.
T. Jegajothivel Pandian 《Helgoland Marine Research》1967,15(1-4):637-647
Summary 1. In the fishOphiocephalus striatus
Bloch feeding rate increased 2 to 3 times, when feeding was resumed after less than 20 days fasting; fasting periods of more than 20 days result in resumption-feeding rates that were only slightly higher (0.5 to 0.8 times) than the controls.2. Although feeding rates were very high after resumption of feeding following different periods of starvation (10 to 40 days) absorption efficiency remained practically identical to that of controls.3. Following a period of less than 20 days fasting resumption of feeding led conversion efficiencies almost twice as high as the normal values, showing over-compensation. Fish fed after a period of more than 20 days fasting showed a decrease in conversion efficiency resulting in partial compensatory growth.4. Responses to resumption of feeding following different periods of starvation may be of two types: (a) Rates of metabolism and feeding are restored to pre-starvation rates and conversion efficiency increases due to corresponding increase in feeding rates, e. g. O.striatus, and (b) rates of metabolism and feeding continue to remain low and the increase in conversion efficiency is due to a corresponding decrease in energy expended on metabolism e. g.,E. lucius.
Part of a Ph. D. Thesis, University of Madras, India. 相似文献
Nahrungsaufnahme, Absorption und Konversion bei dem FischOphiocephalus striatus
Kurzfassung Individuen vonOphiocephalus striatus Bloch wurden nach verschieden langen Hungerzeiten gefüttert, um Aufschlüsse über Aufnahme, Absorption und Konversion der Nahrung zu erhalten. Nach einer Hungerperiode von weniger als 20 Tagen nahm die Nahrungsaufnahme um das Dreifache zu. Hungerten die Tiere länger als 20 Tage, so steigerte sich die Nahrungsaufnahme hingegen nur geringfügig. Trotz der erhöhten Nahrungsaufnahme war der Absorptions-Nutzeffekt dem der Kontrolltiere gleich. Der Konversions-Nutzeffekt verdoppelte sich bei Individuen, die weniger als 20 Tage gehungert hatten; daraus resultierte eine Überkompensation des Wachstums. Bei Tieren, die nach einer Hungerperiode von mehr als 20 Tagen wieder gefüttert wurden, konnte eine gewisse Verringerung des Konversions-Nutzeffektes sowie eine teilweise Kompensation festgestellt werden. Diese Ergebnisse werden im Hinblick auf ähnliche Versuche beiEsox lucius (Ivlev 1939) diskutiert. Es wird die Schlußfolgerung gezogen, daß sich bei Fischen, die nach verschieden langen Hungerzeiten erneut gefüttert werden, zwei Typen unterscheiden lassen: beim ersten Typ ist die Nahrungsaufnahme geringer als vor der Hungerzeit, der Konversions-Nutzeffekt jedoch durch Erniedrigung der für den Stoffwechsel aufgebrachten Energie erhöht; beim zweiten Typ erreichen Nahrungsaufnahme und Stoffwechselintensität sofort die Werte vor der Hungerzeit oder übertreffen diese sogar. Hierbei wird die Erhöhung der Nahrungsaufnahme von einer entsprechenden Vergrößerung des Konversions-Nutzeffektes begleitet.
Part of a Ph. D. Thesis, University of Madras, India. 相似文献