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61.
Human visual recognition processes are remarkably robust and can function effectively even under highly degraded viewing conditions. Contextual information may play a critical role in such circumstances. Here, we provide neurophysiological evidence that contextual cues can elicit object-specific neural responses, which have hitherto been believed to be based on intrinsic cues alone. Specifically, we find that the "fusiform face area" (FFA) maintains its selectivity for faces without regard to whether the faces are defined intrinsically or contextually. This finding further elucidates the role of the FFA and reveals neural correlates of contextual processing in the service of robust object recognition. 相似文献
62.
Interspecies conversion of Clostridium botulinum type C to Clostridium novyi type A by bacteriophage 总被引:11,自引:0,他引:11
When Clostridium botulinum type C is cured of its prophage it simultaneously ceases to produce toxin. This nontoxigenic culture can then be converted to another toxigenic bacterial species, Clostridium novyi type A or to toxigenic Clostridium botulinum types C or D, by specific bacteriophages. The toxigenicity and type of toxin produced by these cultures depends upon the continued presence of these bacteriophages. 相似文献
63.
A marine form of nematode, Aphelenchoides sp., can develop and reproduce effectively on viable mycelia of various filamentous fungi including certain widespread marine species. The efficiency of utilization of fungal mycelium by the animal, based on the ratio of the number of nematodes to the dry weight of fungal mycelium, varies greatly among fungi, from less than 100 to as much as 5000 for several of the marine species studied. 相似文献
64.
65.
Molecular testing of adult Pacific salmon and trout (Oncorhynchus spp.) for several RNA viruses demonstrates widespread distribution of piscine orthoreovirus in Alaska and Washington
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M K Purcell R L Powers J Evered J Kerwin T R Meyers B Stewart J R Winton 《Journal of fish diseases》2018,41(2):347-355
This research was initiated in conjunction with a systematic, multiagency surveillance effort in the United States (U.S.) in response to reported findings of infectious salmon anaemia virus (ISAV) RNA in British Columbia, Canada. In the systematic surveillance study reported in a companion paper, tissues from various salmonids taken from Washington and Alaska were surveyed for ISAV RNA using the U.S.‐approved diagnostic method, and samples were released for use in this present study only after testing negative. Here, we tested a subset of these samples for ISAV RNA with three additional published molecular assays, as well as for RNA from salmonid alphavirus (SAV), piscine myocarditis virus (PMCV) and piscine orthoreovirus (PRV). All samples (n = 2,252; 121 stock cohorts) tested negative for RNA from ISAV, PMCV, and SAV. In contrast, there were 25 stock cohorts from Washington and Alaska that had one or more individuals test positive for PRV RNA; prevalence within stocks varied and ranged from 2% to 73%. The overall prevalence of PRV RNA‐positive individuals across the study was 3.4% (77 of 2,252 fish tested). Findings of PRV RNA were most common in coho (Oncorhynchus kisutch Walbaum) and Chinook (O. tshawytscha Walbaum) salmon. 相似文献
66.
Kingston JK Bayly WM Sellon DC Meyers KM Wardrop KJ 《American journal of veterinary research》2001,62(4):547-554
OBJECTIVE: To investigate the effects of sodium citrate, low molecular weight heparin (LMWH), and prostaglandin E1 (PGE1) on aggregation, fibrinogen binding, and enumeration of equine platelets. SAMPLE POPULATION: Blood samples obtained from 4 Thoroughbreds. PROCEDURE: Blood was collected into syringes in the ratio of 9 parts blood:1 part anticoagulant. Anticoagulants used were sodium citrate, LMWH, sodium citrate and LMWH, or 300 nM PGE1/ml of anticoagulant. Platelet aggregation in response to ADP, collagen, and PGE1 was assessed, using optical aggregometry. Platelet activation was evaluated, using flow cytometry, to detect binding of fluorescein-conjugated anti-human fibrinogen antibody. Plasma concentration of ionized calcium was measured, using an ion-selective electrode. RESULTS: Number of platelets (mean +/- SEM) in samples containing LMWH (109.5+/-11.3 x 10(3) cells/microl) was significantly less than the number in samples containing sodium citrate (187.3+/-30.3 x 10(3) cells/microl). Increasing concentrations of sodium citrate resulted in reductions in platelet aggregation and plasma concentration of ionized calcium. Addition of PGE1 prior to addition of an agonist inhibited platelet aggregation in a concentration-dependent manner, whereas addition of PGE1 4 minutes after addition of ADP resulted in partial reversal of aggregation and fibrinogen binding. CONCLUSIONS AND CLINICAL RELEVANCE: A high concentration of sodium citrate in blood samples decreases plasma concentration of ionized calcium, resulting in reduced platelet aggregation and fibrinogen binding. Platelets tend to clump in samples collected into LMWH, precluding its use as an anticoagulant. Platelet aggregation and fibrinogen binding can be reversed by PGE1, which may result in underestimation of platelet activation. 相似文献
67.
Kingston JK Bayly WM Sellon DC Meyers KM Wardrop KJ 《American journal of veterinary research》2002,63(4):513-519
OBJECTIVE: To investigate the potential use of fluorescent-labeled annexin V, anti-human fibrinogen antibody, and anti-human thrombospondin antibody for detection of the activation of equine platelets by use of flow cytometry. SAMPLE POPULATION: Platelets obtained from 6 Thoroughbreds. PROCEDURE: Flow cytometry was used to assess platelet activation as indicated by detection of binding of fluorescent-labeled annexin V, anti-human fibrinogen antibody, and anti-thrombospondin antibody to unactivated and ADP-, collagen-, platelet activating factor (PAF)-, and A23187-activated equine platelets. Human platelets were used as control samples. Determination of 14C-serotonin uptake and release was used to assess the extent of platelet secretion. RESULTS: Anti-human thrombospondin antibody failed to bind to equine platelets. Annexin V bound to platelets activated with PAF or A23187 when platelets had undergone secretion. Anti-human fibrinogen antibody bound to ADP-, PAF-, and A23817-activated platelets, but binding was not dependent on platelet secretion. The extent of binding of anti-fibrinogen antibody was less in equine platelets, compared with that for human platelets, despite maximal stimulation. CONCLUSIONS AND CLINICAL RELEVANCE: Activation of equine platelets can be detected by use of fluorescent-labeled annexin V and anti-human fibrinogen antibody but not by use of anti-human thrombospondin antibody. These flow cytometric techniques have the potential for detection of in vivo platelet activation in horses at risk of developing thrombotic disorders. 相似文献
68.
M.C. Meyers MS G.D. Potter PhD J.W. Evans PhD L.W. Greene PhD S.F. Crouse PhD 《Journal of Equine Veterinary Science》1989,9(4)
Six mature Quarter Horse-type geldings were used in a replicated 3 × 3 Latin square experiment to determine the effects of adding 5 or 10% feed-grade rendered animal fat to the concentrate diet fed to performance horses. The experiment was conducted over a 14-day pre-trial period to acquaint horses to the experimental apparatus, a 28-day conditioning period and 3 diet treatment periods of 21 days, each conducted in a Latin square arrangement. The horses were exercised on a dirt track and diet effects were evaluated during and following a submaximal exercise test (SET) on an equine treadmill. Physiological responses to the SET were determined following each experimental period. Relative to the control, the horses required 21% and 25% less of the concentrate feed (P<.05), containing 5% and 10% added fat, respectively. There was an increase (P<.05) in muscle glycogen concentration as fat was added to the diet. There were no differences due to feeding fat in nutrient digestibility or in oxygen consumption, ventilatory capacity, respiratory quotient, heart rate blood lactate or blood pH during the SET. However, there was an overall decrease (P<.05) in blood glucose and total lipid concentration, when 10% fat was added to the concentrate diet 相似文献
69.
Cappellato Rosanna Peters Norman E. Meyers Tilden P. 《Water, air, and soil pollution》1998,103(1-4):151-171
Atmospheric deposition and above-ground cycling of sulfur (S) were evaluated in adjacent deciduous and coniferous forests at the Panola Mountain Research Watershed (PMRW), Georgia, U.S.A. Total atmospheric S deposition (wet plus dry) was 12.9 and 12.7 kg ha-1 yr-1 for the deciduous and coniferous forests, respectively, from October 1987 through November 1989. Dry deposition contributes more than 40% to the total atmospheric S deposition, and SO2 is the major source (~55%) of total dry S deposition. Dry deposition to these canopies is similar to regional estimates suggesting that 60-km proximity to emission sources does not noticeably impact dry deposition at PMRW. Below-canopy S fluxes (throughfall plus stemflow) in each forest are 37% higher annually in the deciduous forest than in the coniferous forest. An excess in below-canopy S flux in the deciduous forest is attributed to leaching and higher dry deposition than in the coniferous forest. Total S deposition to the forest floor by throughfall, stemflow and litterfall was 2.4 and 2.8 times higher in the deciduous and coniferous forests, respectively, than annual S growth requirement for foliage and wood. Although S deposition exceeds growth requirement, more than 95% of the total atmospheric S deposition was retained by the watershed in 1988 and 1989. The S retention at PMRW is primarily due to SO4 2- adsorption by iron oxides and hydroxides in watershed soils. The S content in white oak and loblolly pine boles have increased more than 200% in the last 20 yr, possibly reflecting increases in emissions. 相似文献
70.
Arsan EL Atkinson SD Hallett SL Meyers T Bartholomew JL 《Journal of fish diseases》2007,30(8):483-491
The parasite responsible for salmonid whirling disease, Myxobolus cerebralis, was introduced to the USA in 1958. It has since spread across the country causing severe declines in wild trout populations, but has never been documented from Alaska. However, while assessing the risk of introduction of M. cerebralis into the state, we detected the parasite using a species-specific polymerase chain reaction (PCR) assay. Testing of 180 hatchery rainbow trout, Oncorhynchus mykiss (Walbaum), by pepsin trypsin digest (PTD) and quantitative PCR (QPCR) revealed 14 positive samples. Infection was confirmed by sequencing the parasite 18S rRNA gene and by a nested PCR assay based on the same gene. Sequence comparison of M. cerebralis from several locations demonstrated the Alaska isolates were genetically distinct and therefore not false-positives arising from contamination during processing. We were unable to visually identify myxospores, indicating that either infection was light or mature spores had not formed. A reference set of fish samples spiked with known numbers of myxospores verified the QPCR and PTD results. This paper presents DNA sequence data from the Alaska M. cerebralis isolates, provides a brief history of the fish and facility of origin, and discusses implications of different testing methods on asymptomatic fish populations. 相似文献