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71.
Summary The effect of various storage parameters on the power usage and tuber weight loss for a fully refrigerated potato store were
investigated. A computer model validated by detailed monitoring of potato stores was used for the calculations. The store
parameters considered were: storage temperature, store relative humidity, local ambient conditions, store capacity or loading
factor, half cooling time and the infiltration rate or air tightness of the store. The investigation showed that the power
consumption was most affected by the storage temperature and the infiltration rate of the store, and that weight loss was
most affected by the half cooling time. 相似文献
72.
Summary Infection withClavibacter michiganensis subsp.sepedonicus reduced transpiration and xylem function in potato plants (Solanum tuberosum) prior to and during wilting. Transpiration depression and subsequent wilting of infected plants appears to result from reduced
xylem function. 相似文献
73.
74.
75.
Per-Erik Mellander Johan Bergh Tomas Lundmark Kevin Bishop 《European Journal of Forest Research》2008,127(1):71-79
Both aboveground and belowground climate affects net primary production (NNP) and forest growth. Little is known about how
above and belowground factors interact. The BIOMASS-model was tested to simulate photosynthetic recovery over a wide range
of soil temperatures created by snow cover manipulations on tree-scale plots in a 20-year-old Scots pine stand in northern
Sweden. The differences in timing of soil warming between the plots covered a span of two months. Carbon assimilation in needles,
sap flow, needle water potential and climatic parameters were measured in the field. The simulations revealed that an early
start of soil warming gave a relatively early photosynthetic recovery and a 7.5% increase of NPP. Late soil warming delayed
the photosynthetic recovery and reduced the NPP by 13.7%. This indicated that soil temperature needed to be accounted for,
as well as air temperature, when analysing photosynthetic recovery and NPP in boreal environment. The effects of differences
in soil temperature were reflected in the simulated photosynthetic recovery. The model did not fully capture the delay of
photosynthetic recovery caused by a late soil warming. It was possible to integrate the complexity of the soil climate effects
into a threshold date for soil thaw, using sapflow measurements together with information about air temperature and a day
degree sum, as long as water availability was not limiting water uptake by roots. Although a more realistic mechanism than
that currently in BIOMASS is desirable as climate change shifts the typical patterns of interplay between air and soil temperature
dynamics. 相似文献
76.
Summary The effect of using radiant heat to quickly warm potatoes and reduce damage in handling after cold storage was investigated.
Two treatments were investigated: tubers dropped 350 mm with no radiant heat applied, and tubers dropped with radiant heat
applied. Both treatments were compared with a control set of tubers which were taken directly out of store. The mean damage
index per tuber was significantly reduced following radiant heat treatment although there were cultivar and size variations.
The temperature profile under radiant heat was also measured which showed an increase in the outside flesh temperature of
8–12°C depending on tuber colour. 相似文献
77.
The addition of the organosilicone surfactant ‘Silwet L77’ at 1-5 ml litre?1 to formulated glyphosate gave complete surface wetting on application to the adaxial leaf surface of perennial ryegrass (Lolium perenne L.). The wetting characteristics of the solution were associated with rapid foliar uptake and near maximal uptake in 3 h compared to greater than 5 h in the absence of ‘Silwet L77’. Evidence is presented showing that solutions containing ‘Silwet L77’ rapidly infiltrate stomata. Rapid uptake did not occur after application to the astomatous abaxial surface of perennial ryegrass leaves. The rapid rate of glyphosate uptake reduced the critical rainfall period to 2 h or less, compared to up to 10 h in the absence of ‘Silwet L77’. The use of ‘Silwet L77’ has major practical implications for the use of glyphosate in regions with unpredictable rainfall or high rainfall frequency. 相似文献
78.
The present study aims to ascertain the influence of gamma-amino butyric acid (GABA)(A or B) receptors on arginine vasopressin (AVP) release in vitro and determine whether E(2) modulates GABA-AVP interaction. Within 10 min of ewe killing, saggital midline hypothalamic slices (from the anterior preoptic area to the mediobasal hypothalamus along with the median eminence, 2-mm thick, two per ewe) were dissected, placed in oxygenated minimum essential media (MEM)-alpha at 4 degrees C and within 2 h were singly perifused at 37 degrees C with oxygenated MEM-alpha (pH 7.4; flow rate 0.15 ml/min), either with or without E(2) (24 pg/ml). After 4-h equilibration, 10-min fractions were collected for 4 h interposed with a 10-min exposure at 60 min to a specific GABA(A or B) receptor agonist or antagonist at various doses (0.1-10 mm). GABA(A) (muscimol; no E(2), n = 7 perifusion chambers, with E(2), n = 11) or GABA(B) (baclofen; no E(2), n = 8, with E(2), n = 15) agonists (10 mm) did not influence AVP concentrations. However, AVP release increased (p < 0.05) 20-30 min after exposure to 10 mm GABA(A or B) antagonists (bicuculline, no E(2), n = 7: from 4.6 +/- 0.7 to 33.0 +/- 0.4, with E(2), n = 17: from 11.9 +/- 1.4 to 32.8 +/- 6.0; CGP52432, with E(2), n = 14: from 14.0 +/- 2.6 to 28.8 +/- 3.9 pg/ml). At the end of the collection period, hypothalamic slices responded to KCl (100 mm) with AVP efflux (p < 0.05). GABA(B) but not GABA(A) antagonist-stimulated AVP release was enhanced in the presence of E(2). In summary, AVP release is under the inhibitory influence of GABA input with further potentiation by E(2) through GABA(B) receptors in vitro. 相似文献
79.
M D Bishop M E Davis W R Harvey G R Wilson B D VanStavern 《Journal of animal science》1991,69(11):4360-4367
A single generation divergent selection study, replicated four times (1983, 1984, 1985, and 1986), was conducted to assess genetic differences between progeny of high and low feed conversion sires in Angus beef cattle and to determine correlated response for weight gain (ADG140), feed intake (AVFD140), and BW (OFFTSTWT) in a time- (140-d) and fat-constant (8.9 mm) period. Realized heritability estimates for unadjusted (feed/gain; FEFF140; .26) and adjusted feed conversion (adjusted as recommended by the BIF, 1986; ADJFDEFF; .46) were obtained. The difference in heritability estimates reflects variation accounted for by adjustment for BW differences, and thus maintenance requirements, of individual progeny. Phenotypic and "pseudo" realized genetic correlations of FEFF140 with ADG140, AVFD 140, and OFFTSTWT were -.33 and -.66, .49 and -.26, and .15 and -.41, respectively. Phenotypic and "pseudo" realized genetic correlations of ADJFDEFF with ADG140, AVFD140, OFFTSTWT, and FEFF140 were -.54 and -.59, .30 and -.23, .27 and -.36, and .97 and .49, respectively. Subcutaneous fat (as estimated by ultrasonic measurement; BF140) had phenotypic and "pseudo" realized genetic correlations with FEFF140 of -.33 and .66, respectively, and with ADJFDEFF of -.44 and -.58, respectively. 相似文献
80.
Jacqueline M. Bishop Alison J. Leslie Sven L. Bourquin Colleen ORyan 《Biological conservation》2009,142(10):2335-2341
Unchecked exploitation of wildlife resources is one of the major factors influencing species persistence throughout the world today. A significant consequence of exploitation is the increasing rate at which genetic diversity is lost as populations decline. Recent studies suggest that life history traits affecting population growth, particularly in long-lived species, may act to moderate the impact of population decline on genetic variation and lead to remnant populations that appear genetically diverse despite having passed through substantial demographic bottlenecks. In this study we show that the retention of genetic variation in a partially recovered population of Nile crocodile is deceptive, as it masks the reality of a significant decline in the population’s effective size (Ne). Repeated episodes of unchecked hunting in the mid to late 20th century have today led to a five-fold decrease in the population’s Ne. Using current census data we estimate the contemporary Ne/N ratio as 0.05 and, in light of quotas that permit the ongoing removal of adults, simulated the likely effects of genetic drift on extant levels of variation. Results indicate that even if the current effective size is maintained, both allelic diversity and heterozygosity will decline. Our findings have complex implications for long-lived species; an emphasis on the retention of genetic variation alone, whilst disregarding the effects of population decline on effective size, may ultimately obscure the continued decline and extinction of exploited populations. 相似文献