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1.
2.
High level of divergence of male-reproductive-tract proteins, between Drosophila melanogaster and its sibling species, D. simulans 总被引:1,自引:0,他引:1
We compared male-reproductive-tract polypeptides of Drosophila melanogaster
and D. simulans by using two-dimensional gel electrophoresis. Approximately
64% of male-reproductive-tract polypeptides were identical between two
randomly chosen isofemale lines from these two species, compared with 83%
identity for third-instar imaginal wing-disc polypeptides. Qualitatively
similar differences were found between reproductive tracts and imaginal
discs when D. sechellia was compared with D. melanogaster and with D.
simulans. When genic polymorphism was taken into account, approximately 10%
of male- reproductive-tract polypeptides were apparently fixed for
different alleles between D. melanogaster and D. simulans; this proportion
is the same as that found for soluble enzymes by one-dimensional gel
electrophoresis. Strikingly, approximately 20% of male-reproductive- tract
polypeptides of either D. melanogaster or D. simulans had no detectable
homologue in the other species. We propose that proteins of the Drosophila
male reproductive tract may have diverged more extensively between species
than have other types of proteins and that much of this divergence may
involve large changes in levels of polypeptide expression.
相似文献
3.
The role of indole-3-butyric acid (IBA) in adventitious root formation was studied by analyzing the uptake and subsequent metabolism of IBA in shoots of M.26 apple (Malus pumila Mill.) rootstock grown in vitro. Roots were induced by exposing shoots to 4 M IBA and [3H]IBA for 5 days in the dark and then transferring them to plant growth regulator (PGR)-free medium in the light until roots formed. Approximately 50% of the total radioactivity applied was taken up from the agar medium by the shoots during the 5-day incubation period in IBA. Indole-3-butyric acid metabolism was studied by extraction and high-performance liquid chromatographic (HPLC) separation of [3H]IBA and metabolites from the basal sections of treated shoots. The major [3H]IBA metabolite co-eluted with authentic [14C]indole-3-acetic acid (IAA) suggesting that IBA was converted to IAA in the shoots. The proportion of newly synthesized IAA present as conjugates was higher at the end of the 5-day IBA treatment period than after 13 days in PGR-free medium. There appeared to be no conjugation of IBA at any time. 相似文献
4.
Summary Cell suspensions of the fresh-watersponge Ephydatia fluviatilis have been fractionated by means ofFicoll gradient centrifugation. Three fractions were isolated. The densest contains archeocyte-like cells only; the intermediate fraction is very rich in choanocytes, and the lightest is a mixture of cell types. Earch fraction shows specificaggregative properties and potentialities to reconstitute functional sponges.It appears that the sequence of reconstitution events can be selectively altered by certain disequilibria in the cell populationThese preliminary results constitute a first approach to the analysis ofcell type specificity in sponges. 相似文献
5.
Measurement of indolebutyric Acid in plant tissues by isotope dilution gas chromatography-mass spectrometry analysis 总被引:4,自引:2,他引:2 下载免费PDF全文
An internal standard, [13C][indole-2]-indole-3-butyric acid, was synthesized from indole-2[13C] and was shown to be effective for the quantitative determination of indole-3-butyric acid from plant tissue. When this standard was used along with [13C6]indole-3-acetic acid, both indolic auxins could be quantified from the same tobacco (Nicotiana tabacam) leaf sample by isotope dilution analysis using selected ion monitoring gas chromatography-mass spectrometry for detection. 相似文献
6.
This study examines the effect of various plasma proteins from man on the spontaneous contractile activity of the rat portal vein. Albumin, gamma-globulin, alpha-globulin, beta-globulin (the major plasma proteins), and immunoglobulin IgG (the major immunoglobulin present in the gamma-globulin fraction) were obtained commercially. Mesenteric portal vein strips were prepared from rats and placed in a physiological salt solution in muscle baths for the measurement of longitudinal mechanical response. Portal veins exposed to albumin or gamma-globulin showed a dose-dependent increase in the spontaneous activity, whereas those exposed to alpha-globulin or alpha- and beta-globulin together showed a dose-dependent inhibition of spontaneous activity. Immunoglobulin IgG produced a dose-dependent increase in the spontaneous activity similar to that of gamma-globulin. The increased spontaneous activity produced by albumin was not prevented by ouabain but was inhibited by phentolamine. Spontaneous contractile activity was stimulated by albumin in the chemically (6-hydroxydopamine) denervated portal vein. These findings indicate that albumin acts in a manner similar to noradrenaline. The increased spontaneous activity caused by gamma-globulin (IgG) was inhibited by ouabain or verapamil. The effect of IgG was not dependent on alpha-adrenergic, cholinergic, histaminergic, serotoninergic, or renin angiotensin systems nor was it affected by removal of the endothelium. These observations may have implications in the pathophysiology of essential hypertension. 相似文献
7.
Under field conditions in eastern South Dakota, USA three different planting dates of corn and three times of egg infestation were used to imposed synchronous and asynchronous timing of corn growth and Diabrotica virgifera virgifera LeConte egg hatch and subsequent development. Median occurrence of each of the three larval stages and of the adult stage for each of the infestation-planting treatments was determined by relating occurrence to thermal units and to days after infestation. No significant differences were found among the treatments for median occurrence of each life stage when the thermal unit approach was used. However, significant differences were found among treatments for median occurrence when the day after infestation approach was used. Consistent parameters are needed for prediction of the occurrence of life stages of this insect. Despite the various imposed conditions, this study indicates that the least variable method of predicting life stage occurrence and adult emergence of D. v. virgifera was the use of thermal unit accumulations (base 11°C).
Résumé Dans les conditions de l'est du Sud Dakota (USA), 3 dates de semailles de maïs et 3 dates de contamination avec des ufs de D. virgifera virgifera LeConte ont servi à imposer ou à empêcher la synchronisation des éclosions des ufs et par conséquent des développements ultérieurs. Les dates médianes d'apparition de chacun des 3 stades larvaires et des imagos ont été déterminées en relation avec les unités de température et le nombre de jours depuis la contamination. Aucune différence significative entre les dates médianes d'apparition n'a été mise en évidence par utilisation des unités de température; par contre, ces différences deviennent significatives lorsque l'on utilise le nombre de jours depuis la contamination. Des paramètres fiables sont nécessaires pour prédire la présence des différentes stades de cet insecte. En dépit des différentes conditions imposées pour cette étude, la méthode la moins capricieuse pour prédire l'apparition d'un stade larvaire et l'émergence des adultes est la somme de températures avec une base de 11°C.相似文献
8.
Ernst Sutter 《Journal of Ornithology》1955,96(2):220-222
Ohne Zusammenfassung 相似文献
9.
C Castex A Tahri R Hoo-Paris B C Sutter 《Comparative biochemistry and physiology. A, Comparative physiology》1987,88(1):33-36
1. The effect of insulin on U-14C-glucose oxidation by adipose tissue isolated from hibernating or arousing edible dormouse has been studied. 2. CO2 production derived from radioglucose was analysed point by point during in vitro rewarming (from 6 to 37 degrees C). 3. The rate of temperature increase was 2 degrees/5 min in order to mimic the rate of rewarming during the spontaneous arousal of the dormouse. 4. Insulin did not increase the glucose oxidation by the adipose tissue from hibernating dormouse whereas adipocytes from active animal present high insulin sensitivity. 5. These results suggest that insulin resistance occurs during hibernation. 相似文献
10.
The epidermal growth factor (EGF) can be isolated from the submaxillary gland of the adult male mouse as part of a high molecular weight complex (HMW-EGF). This complex can be reversibly dissociated into its subunits, EGF AND EGF-binding protein, an arginine esteropeptidase (Taylor, J. M., Cohen, S., and Mitchell, W. M. (1970) Proc. Natl. Acad. Sci. U. S. A. 67, 164-171). The COOH-terminal arginine residue of EGF was quantitatively removed by digestion with carboxypeptidase B... 相似文献