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P. L. MILLER 《Physiological Entomology》1990,15(2):199-209
ABSTRACT An account of the structure of the secondary genitalia of male Orthetrum coerulescens (Fabricius) is given together with an outline of the internal genitalia of the female. Observations on the experimental inflation of the penis are described. No sperm was released during fast inflations and deflations of the penis, but sustained inflation of the penis led to the release of a clear fluid followed by the slow discharge of sperm. Examination of natural copulations in the field has shown that rapid rhythmic movements at up to 5 Hz take place in the male's third abdominal segment throughout most of copulation, but towards the end they cease though inflation is maintained. It is suggested that the rapid movements coincide with the removal of rival sperm from the female and that sperm is transferred to the female only during the maintained inflation. Possible mechanisms of sperm translocation, sperm removal and sperm transfer are discussed with reference to male and female genital structures and the action of relevant muscles. 相似文献
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The effect of fluoride on the respiration of leaves from Chenopodiummurale and soybean [Glycine max, Merr., Hawkeye variety) wasstudied. Fluoride treatment included both excised leaves culturedin nutrient solutions and leaves from plants fumigated withHP atmosphere. Tissues treated with low fluoride concentrationswhich initially showed increased oxygen uptake eventually showeddecreased oxygen consumption. Tissues treated with a high concentrationof fluoride showed an increased oxygen uptake if analyzed soonafter treatment initiation. Increase in respiration generallytook place before visible damage was manifested. Decrease inrespiration was correlated with pronounced injury of tissues.Besides concentration of fluoride and the time lapse of treatment,the pH of the culture solution in which fluoride was supplemented,tissue age, and plant species, were important factors affectingrespiration. The effect of 2, 4-dinitrophenol (DNP) on respirationwas very similar to that of fluoride in that the effect differedwith pH, concentrations, time of treatment, leaf age, and plantspecies. The respiration of fluoride treated leaves was stimulatedless by DNP than that of control leaves. (Received July 18, 1967; ) 相似文献
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Determination of metabolic resistance mechanisms in pyrethroid‐resistant and fipronil‐tolerant brown dog ticks 下载免费PDF全文
A. L. EIDEN P. E. KAUFMAN F. M. OI M. J. DARK J. R. BLOOMQUIST R. J. MILLER 《Medical and veterinary entomology》2017,31(3):243-251
Rhipicephalus sanguineus (Latreille) (Ixodida: Ixodidae) is a three‐host dog tick found worldwide that is able to complete its' entire lifecycle indoors. Options for the management of R. sanguineus are limited and its' control relies largely on only a few acaricidal active ingredients. Previous studies have confirmed permethrin resistance and fipronil tolerance in R. sanguineus populations, commonly conferred by metabolic detoxification or target site mutations. Herein, five strains of permethrin‐resistant and three strains of fipronil‐tolerant ticks were evaluated for metabolic resistance using synergists to block metabolic enzymes. Synergist studies were completed with triphenyl phosphate (TPP) for esterase inhibition, piperonyl butoxide (PBO) for cytochrome P450 inhibition, and diethyl maleate (DEM) for glutathione‐S‐transferase inhibition. Additionally, increased esterase activity was confirmed using gel electrophoresis. The most important metabolic detoxification mechanism in permethrin‐resistant ticks was increased esterase activity, followed by increased cytochrome P450 activity. The inhibition of metabolic enzymes did not have a marked impact on fipronil‐tolerant tick strains. 相似文献
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The investigations leading to an explanation of the mechanismof sperm chemotaxis in the hydrozoa depend heavily on purificationand identification of the compounds responsible for the attraction.The substance (s) are of low molecular weight, are stable toheat and to high and low pH under moderate conditions, and arehighly positively charged. Recent work using the attractantfrom Tubularia indicates that ion-exchange chromatography coupledwith the proper gradient elution techniques is beginning toyield partially purified attractant. The biological activityis eliminated after strong-acid hydrolysis and after treatmentwith crude proteolytic enzymes, like pronase and pancreatin.The active components of these mixtures of enzymes are neutralproteases with a serine residue in the active site. The stabilityof the molecule (s) to pH, their apparent ninhydrin-insensitivity,and their chromatographic behavior are indicative of a low molecular-weightpeptide, possibly one of the cyclic peptides. Promising avenuesleading to further purification have been opened up by the workreported here, and it would appear to be only a matter of timebefore pure attractant is available for chemical analysis. 相似文献