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51.
David L. G. Noakes 《Environmental Biology of Fishes》1979,4(4):389-400
Synopsis Parent-touching behavior by young fishes occurs in a number of species. Most reports have been from the family Cichlidae, but this may reflect the major concentration of studies on these species. The behavior appears to serve a trophic function in many species, but may also serve to maintain cohesion of family groups, to keep adults in a parental state, or to communicate the motivational state of the young (e.g. fear, hunger). It has been suggested that prolactin may regulate the behavior and epidermal mucus condition in parental fish involved in such behavior, but the evidence is not conclusive. There appear to be similarities between cases of parent-touching as a trophic behavior, and mucus- and/or scale-feeding by cleaning symbionts or predators. Studies of this behavior hold promise for investigating interrelationships between endocrinology and behavior, and ecology and behavior. 相似文献
52.
BA Payseur HA Covert CJ Vinyard M Dagosto 《American journal of physical anthropology》1999,110(1):115-116
Payseur BA, Covert HA, Vinyard CJ, Dagosto M. 1999. New Body Mass Estimates for Omomys carteri, a Middle Eocene Primate From North America. Am J Phys Anthropol 109:41–52. This article included an incomplete Table 2. The final two columns, showing “Intercept” and “SEE” data were omitted. The complete Table 2, with these two columns included, is provided below. 相似文献
53.
Paul Vecsei Matthew K. Litvak David L.G. Noakes Tom Rien Martin Hochleithner 《Environmental Biology of Fishes》2003,68(4):333-338
We have developed a noninvasive technique to determine the sex of adult North American sturgeon by examination of the external morphology of live individuals. We analyzed four sturgeon species taken by commercial and scientific harvest: white Acipenser transmontanus, green A. medirostris, Atlantic A. oxyrinchus and shortnose A. brevirostrum. Males have a urogenital opening in the shape of a letter Y, while the opening of females is in the shape of the letter O. We accurately sexed 26 of 36 sturgeon using this criterion. Accuracy was highest in live fish (82%), and significantly lower in dead fish (29%). Dead sturgeon usually have the rectum prolapsed so that the urogenital opening is protruded, and thus making the sexes indistinguishable. 相似文献
54.
Gladys B. Ismail David B. Sampson David L. G. Noakes 《Environmental Biology of Fishes》2014,97(4):425-434
The endemic cyprinid species flock of Lake Lanao, Philippines is a classic example of explosive evolution. Based on historical surveys, most of the 18 endemic cyprinid species in Lake Lanao are now believed to be extinct. We compared results of landing and market surveys conducted in 2008 to information from historical surveys. Field sampling and fishermen interviews provided additional information on the status of the endemic and other fish species in Lake Lanao. Puntius lindog and Puntius tumba were the only two endemic species recorded in 2008, accounting for 0.01 % and 0.04 % respectively of the total weight harvested. Our discovery that at least two endemic cyprinids remain in Lake Lanao is surprising and significant as the lake is increasingly imperiled by human disturbances, exploitation and introduced species. Protecting and conserving the remaining endemic species are important management priorities. 相似文献
55.
John A. Hawley Garry S. Palmer Timothy D. Noakes 《European journal of applied physiology and occupational physiology》1997,75(5):407-412
This study compared the effects of supplementing the normal diets of six trained cyclists [maximal oxygen uptake O2max) 4.5 (0.36)l · min−1; values are mean (SD)] with additional carbohydrate (CHO) on muscle glycogen utilisation during a 1-h cycle time-trial (TT).
Using a randomised crossover design, subjects consumed either their normal diet (NORM) for 3 days, which consisted of 426
(137) g · day−1 CHO [5.9 (1.4) g · kg−1 body mass (BM)], or additional CHO (SUPP) to increase their intake to 661 (76) g · day−1 [9.3 (0.7) g · kg−1 BM]. The SUPP diet elevated muscle glycogen content from 459 (83) to 565 (62) mmol · kg−1 dry weight (d.w.) (P < 0.05). However, despite the increased pre-exercise muscle glycogen stores, there was no difference in the distance cycled
during the TT [40.41 (1.44) vs 40.18 (1.76) km for NORM and SUPP, respectively]. With NORM, muscle glycogen declined from
459 (83) to 175 (64) mmol · kg−1 d.w., whereas with SUPP the corresponding values were 565 (62) and 292 (113) mmol · kg−1 d.w. Accordingly, both muscle glycogen utilisation [277 (64) vs 273 (114) mmol · kg−1 d.w.] and total CHO oxidation [169 (20) vs 165 (30) g · h−1 for NORM and SUPP, respectively] were similar. Neither were there any differences in plasma glucose or lactate concentrations
during the two experimental trials. Plasma glucose concentration averaged 5.5 (0.5) and 5.6 (0.6) mmol · l−1, while plasma lactate concentration averaged 4.4 (1.9) and 4.4 (2.3) mmol · l−1 for NORM and SUPP, respectively. The results of this study show that when well-trained subjects increase the CHO content
of their diet for 3 days from 6 to 9 g · kg−1 BM there is only a modest increase in muscle glycogen content. Since supplementary CHO did not improve TT performance, we
conclude that additional CHO provides no benefit to performance for athletes who compete in intense, continuous events lasting
1 h. Furthermore, the substantial muscle CHO reserves observed at the termination of exercise indicate that whole-muscle glycogen
depletion does not determine fatigue at this exercise intensity and duration.
Accepted: 25 November 1996 相似文献
56.
CJ Cooksey 《Biotechnic & histochemistry》2014,89(8):564-567
Trypan blue is colorant from the 19th century that has an association with Africa as a chemotherapeutic agent against protozoan (Trypanosomal) infections, which cause sleeping sickness. The dye still is used for staining biopsies, living cells and organisms, and it also has been used as a colorant for textiles. 相似文献
57.
Matthew J. Noakes Ben Smit Blair O. Wolf Andrew E. McKechnie 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2013,183(7):969-982
Columbid birds represent a useful model taxon for examining adaptation in metabolic and thermal traits, including the effects of insularity. To test predictions concerning the role of insularity and low predation risk as factors selecting for the use of torpor, and the evolution of low basal metabolic rate in island species, we examined thermoregulation under laboratory and semi-natural conditions in a mainland species, the African Green Pigeon (Treron calvus). Under laboratory conditions, rest-phase body temperature (T b) was significantly and positively correlated with air temperature (T a) between 0 and 35 °C, and the relationship between resting metabolic rate (RMR) and T a differed from typical endothermic patterns. The minimum RMR, which we interpret as basal metabolic rate (BMR), was 0.825 ± 0.090 W. Green pigeons responded to food restriction by significantly decreasing rest-phase T b, but the reductions were small (at most ~5 °C below normothermic values), with a minimum T b of 33.1 °C recorded in a food-deprived bird. We found no evidence of the large reductions in T b and metabolic rate and the lethargic state characteristic of torpor. The absence of torpor in T. calvus lends support to the idea that species restricted to islands that are free of predators are more likely to use torpor than mainland species that face the risk of predation during the rest-phase. We also analysed interspecific variation in columbid BMR in a phylogenetically informed framework and verified the conclusions of an earlier study which found that BMR is significantly lower in island species compared to those that occur on mainlands. 相似文献
58.
Maarten van den Berge Wim CJ Hop Thys van der Molen Jan A van Noord Jacques PHM Creemers Ad JM Schreurs Emiel FM Wouters Dirkje S Postma 《Respiratory research》2012,13(1):44
Background
Frequent exacerbations induce a high burden to Chronic Obstructive Pulmonary Disease (COPD). We investigated the course of exacerbations in the published COSMIC study that investigated the effects of 1-year withdrawal of fluticasone after a 3-month run-in treatment period with salmeterol/fluticasone in patients with COPD.Methods
In 373 patients, we evaluated diary cards for symptoms, Peak Expiratory Flow (PEF), and salbutamol use and assessed their course during exacerbations.Results
There were 492 exacerbations in 224 patients. The level of symptoms of cough, sputum, dyspnea and nocturnal awakening steadily increased from 2 weeks prior to exacerbation, with a sharp rise during the last week. Symptoms of cough, sputum, and dyspnea reverted to baseline values at different rates (after 4, 4, and 7 weeks respectively), whereas symptoms of nocturnal awakening were still increased after eight weeks. The course of symptoms was similar around a first and second exacerbation. Increases in symptoms and salbutamol use and decreases in PEF were associated with a higher risk to develop an exacerbation, but with moderate predictive values, the areas under the receiver operating curves ranging from 0.63 to 0.70.Conclusions
Exacerbations of COPD are associated with increased symptoms that persist for weeks and the course is very similar between a first and second exacerbation. COPD exacerbations are preceded by increased symptoms and salbutamol use and lower PEF, yet predictive values are too low to warrant daily use in clinical practice. 相似文献59.
Menon KI Feldwick MG Noakes PS Mead RJ 《Journal of biochemical and molecular toxicology》2001,15(1):47-54
The biochemical toxicology of 1,3-difluoroacetone, a known metabolite of the major ingredient of the pesticide Gliftor (1,3-difluoro-2-propanol), was investigated in vivo and in vitro. Rat kidney homogenates supplemented with coenzyme A, ATP, oxaloacetate, and Mg2+ converted 1,3-difluoroacetone to (-)-erythro-fluorocitrate in vitro. Administration of 1,3-difluoroacetone (100 mg kg(-1) body weight) to rats in vivo resulted in (-)-erythro-fluorocitrate synthesis in the kidney, which was preceded by an elevation in fluoride levels and followed by citrate accumulation. Animals dosed with 1,3-difluoroacetone did not display the 2-3 hour lag phase in either (-)-erythro-fluorocitrate synthesis or in citrate and fluoride accumulation characteristic of animals dosed with 1,3-difluoro-2-propanol. We demonstrate that the conversion of 1,3-difluoro-2-propanol to 1,3-difluoroacetone by an NAD+-dependent oxidation is the rate-limiting step in the synthesis of the toxic product, (-)-erythro-fluorocitrate from 1,3-difluoro-2-propanol. Prior administration of 4-methylpyrazole (90 mg kg(-1) body weight) was shown to prevent the conversion of 1,3-difluoro-2-propanol (100 mg kg(-1) body weight) to (-)-erythro-fluorocitrate in vivo and to eliminate the fluoride and citrate elevations seen in 1,3-difluoro-2-propanol-intoxicated animals. However, administration of 4-methylpyrazole (90 mg kg(-1) body weight) to rats 2 hours prior to 1,3-difluoroacetone (100 mg kg(-1) body weight) was ineffective in preventing (-)-erythro-fluorocitrate synthesis and did not diminish fluoride or citrate accumulation in vivo. We conclude that the prophylactic and antidotal properties of 4-methylpyrazole seen in animals treated with 1,3-difluoro-2-propanol derive from its capacity to inhibit the NAD+-dependent oxidation responsible for converting 1,3-difluoro-2-propanol to 1,3-difluoroacetone in the committed step of the toxic pathway. 相似文献
60.
Multiple duplications of yeast hexose transport genes in response to selection in a glucose-limited environment 总被引:9,自引:2,他引:9
When microbes evolve in a continuous, nutrient-limited environment, natural
selection can be predicted to favor genetic changes that give cells greater
access to limiting substrate. We analyzed a population of baker's yeast
that underwent 450 generations of glucose-limited growth. Relative to the
strain used as the inoculum, the predominant cell type at the end of this
experiment sustains growth at significantly lower steady-state glucose
concentrations and demonstrates markedly enhanced cell yield per mole
glucose, significantly enhanced high-affinity glucose transport, and
greater relative fitness in pairwise competition. These changes are
correlated with increased levels of mRNA hybridizing to probe generated
from the hexose transport locus HXT6. Further analysis of the evolved
strain reveals the existence of multiple tandem duplications involving two
highly similar, high- affinity hexose transport loci, HXT6 and HXT7.
Selection appears to have favored changes that result in the formation of
more than three chimeric genes derived from the upstream promoter of the
HXT7 gene and the coding sequence of HXT6. We propose a genetic mechanism
to account for these changes and speculate as to their adaptive
significance in the context of gene duplication as a common response of
microorganisms to nutrient limitation.
相似文献