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31.
Lactoferrin (LF) is an iron-binding protein present in both colostrum and secondary granules of polymorphonuclear neutrophils (PMNs). We hypothesized that supplemental LF enhances neutrophil function in neonatal calves. Newborn calves were assigned to receive colostrum (C), colostrum + LF (CLF, 1 g/kg), or milk replacer + LF (MRLF, 1 g/kg). Serum (LF and IgG) and whole blood (neutrophil isolation) samples were obtained prior to treatment (day 0) and at 24 hours and 9 days of age. Serum IgG concentrations (mean +/- SD) in C, CLF, and MRLF calves at 24 hours were 1,911 +/- 994 mg/dL, 2,181 +/- 625 mg/dL, and 0 mg/ dL, respectively. Serum LF concentrations in C, CLF, and MRLF calves on day 0 were 324 +/- 334 ng/mL (range 0-863 ng/mL), 135 +/- 158 ng/mL (range 0-429 ng/mL), and 318 +/- 337 ng/mL (range 0-964 ng/mL), respectively. LF concentrations in C, CLF, and MRLF calves at 24 hours were significantly higher (P < .05), at 1,564 +/- 1,114 ng/mL (range 335-3,628 ng/mL, 2,237 +/- 936 ng/mL (range 31-3,287 ng/mL), and 3,189 +/- 926 ng/mL (range 1,736-4,120 ng/mL), respectively. Cytochrome c reduction in opsonized zymosan-treated or phorbol ester-treated cells was not significantly affected by supplemental LF provided at birth. Oral LF is absorbed in calves but does not alter PMN superoxide production and does not alter IgG absorption.  相似文献   
32.
Epizootic ulcerative syndrome was diagnosed, and the presence of Aphanomyces invadans confirmed, from an outbreak of clinical disease in wild‐caught bony bream (Nematalosa erebi) from the Darling River near Bourke, in New South Wales, Australia, during 2008. This confirms a significant extension of the agent beyond its historical range.  相似文献   
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The relationship between microbial diagenesis of Sphagnum peat (SP) and reed-sedge peat (RSP) and the spatial organization of peat bacterial communities was studied. Peats were aerobically incubated at 18-22 °C for 4 months. Changes in molecular composition of peat organic matter were monitored with solid-state 13C NMR, and the respective amount of functional groups was determined by integration of corresponding peaks. No abiotic peat transformation was detected. SP diagenesis caused about a 4% loss of parent materials with a similar yield of ketones, phenols, aromatic, and carbonyl compounds; whereas about 20% of RSP carbohydrates, along with ketones and methoxyl compounds were gradually transformed into carbonyl and aliphatic compounds. SP and RSP substantially varied in bacterial composition. To address spatial community structure, bacterial populations were dissected by a differential elution technique into three fractions based on the degree of their attachment to peat. Community composition was surveyed with T-RFLP (HhaI, MspI, and RsaI). The fragments were further attributed to freely-dispersed (FD), particle-associated (PA), or omnipresent (OMN) bacterial fractions. In both peats, bacterial communities have gradually shifted with the progress of diagenesis. In SP, numbers of exclusively FD or PA bacteria slightly decreased while in RSP their numbers more than doubled after 4-month incubation, and the number of OMN bacteria respectively decreased. The substantially greater changes in the spatial structure of RSP bacterial community compared to SP were consistent with the chemical transformations detected in these peats suggesting the diagenesis-driven divergence of RSP bacterial community into FD and PA sub-communities.  相似文献   
35.
Mycobacterium avium subsp. paratuberculosis is an important pathogen that causes Johne's disease in animals and has been implicated in Crohn's disease in man yet few data exist on its physiological adaptation in either the host or the environment. In this study, the proteomic responses of the two distinct strains of M. a. paratuberculosis, cattle (C) and sheep (S), to hypoxia and starvation were studied in vitro. Nutrient starvation inhibited growth of both strains and was lethal for S strain after 12 weeks. Hypoxia induced a state of very low metabolic activity but rapid resuscitation occurred upon restoration of an aerobic atmosphere, consistent with the dormancy response of other mycobacteria. A total of 55 protein spots differentially expressed in response to starvation and/or hypoxic stress in one or both strains were identified from 2D gels and classified based on biological function. Antioxidant enzymes, oxidoreducatse enzymes and proteins involved in amino acid metabolism, fatty acid metabolism, ATP and purine biosynthesis, proteolysis, cell wall synthesis, protein synthesis, signal recognition and hypothetical proteins with putative functions including dormancy response regulators and universal stress proteins were identified. These proteins are potential screening targets for future diagnosis, prevention and control of M. a. paratuberculosis infection and their identification will assist understanding the pathogenesis of diseases caused by this organism.  相似文献   
36.
Objective: To evaluate: (1) an arthroscopic technique for transection of the collateral sesamoidean ligament (CSL); and (2) the healing response using magnetic resonance (MR) and microscopic examination. Study Design: Experimental study. Animals: Adult horses (n=6). Methods: Six sound horses with normal front foot radiographic and MR examinations were used. Lameness examination was performed before surgery and monthly for 12 months. Front foot radiography was performed at 180 and 360 days after surgery. Front foot MR was performed before, and at 7, 90, 180, and 360 days after surgery. Arthroscopic CSL desmotomy was performed on 1 forelimb. Gross and microscopic examination was performed on the CSL from both forelimbs at 360 days after surgery. Lameness scores were compared over time using the nonparametric Friedman's test for paired groups. CSL measurements were compared using paired t‐tests with a 2‐tailed significance level of P<.05. Results: Radiographs remained normal throughout study period. Surgery resulted in lameness on the operated limb for up to 2 months, after which all horses returned to soundness. CSL transection was confirmed during arthroscopy and with MR examination 7 days after surgery. Gross and microscopic evaluation confirmed ligament healing. Conclusions: CSL desmotomy resulted in short‐term lameness after surgery followed by healing of the CSL confirmed by gross and microscopic analysis.  相似文献   
37.
Portfolio theory, an established technique in the selection of stocks and financial instruments for investment purposes, was used as a means of selecting an economic mix of veterinary interventions in a dairy herd. The expected return on investment in six veterinary services and the associated standard deviations (as measures of risk) were calculated using computer simulation modeling techniques. Mathematical programming techniques were applied to identify the optimal combinations of veterinary interventions which maximize expected financial returns while minimizing risk. Parametric analysis was used to show how risk (standard deviation) increases as the required expected return is increased along the efficient risk-return frontier of these optimal combinations. This exercise emphasizes the importance of regarding risk in addition to expected return when considering investment in veterinary services.  相似文献   
38.
This prospective study involved 845 Holstein heifer calves born during 1991 on 30 dairy farms in southeast Minnesota. The objectives of the part of the study reported here were to examine relationships between management practices and incidence of morbidity and mortality at both herd and individual-calf levels. A survey administered by the investigators identified the herd management practices. Check-off forms completed by cooperating producers captured the individual-calf risk factors. Data collected included events surrounding each calf's birth as well as treatments and disease diagnoses for each heifer calf. Outcomes of interest were any occurrence of enteritis, pneumonia, or death between birth and 16 weeks of age. Time, place and date of birth, ease of birth, colostrum administration and any other treatments at birth, housing and any other treatments were the risk factors of interest. The overall morbidity rate for the study was 0.2 calves treated per 100 calf-days at risk (range 0-0.8, standard deviation 0.2), while the rates for scours and pneumonia were 0.15 cases per 100 calf-days at risk (0-0.7, ± 0.2) and 0.10 (0-0.7, ± 0.2) cases per 100 calf-days at risk, respectively. The mortality rate for the study period was 0.08 deaths per 100 calf-days at risk (0-0.3, ± 0.08); 64 heifers (7.5%) died during the study. Mean average daily weight gains for heifers from birth to 16 weeks of age was 0.82 kg day−1 for all farms (0.45–1.1, ± 0.2). In general, stated herd management practices were practiced at the individual-calf level. Several herd management practices altered the outcomes of interest. For example, the feeding of a coccidiostat to preweaned calves increased the herd risk of pneumonia (relative risk, 3.38; 95% CI 1.34–8.50). The feeding of a vitamin A-D-E supplement to preweaned calves exerted a protective effect against scours (0.35, 0.13–0.93). Managing group pens for weaned calves in an ‘all-in, all-out’ fashion rather than in a continuous flow system contributed to a farm having an average daily rate of gain that was above the median (3.06, 1.34–6.97). The Cox proportional hazards model was used to describe relationships between risk factors and the outcomes of interest. Calves that required assisted delivery were at an increased risk of developing enteritis sooner than those that were born without assistance. No other risk factors had a significant effect.  相似文献   
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Agricultural fairs create an unconventional animal–human interface that has been associated with swine‐to‐human transmission of influenza A virus (IAV) in recent years. Early detection of IAV‐infected pigs at agricultural fairs would allow veterinarians to better protect swine and human health during these swine exhibitions. This study assessed the use of swine body temperature measurement, recorded by infrared and rectal thermometers, as a practical method to detect IAV‐infected swine at agricultural fairs. In our first objective, infrared thermometers were used to record the body surface temperature of 1,092 pigs at the time of IAV nasal swab collection at the end of the exhibition period of 55 agricultural fairs. IAV was recovered from 212 (19.4%) pigs, and the difference in mean infrared body temperature measurement of IAV‐positive and IAV‐negative pigs was 0.83°C. In a second objective, snout wipes were collected from 1,948 pigs immediately prior to the unloading of the animals at a single large swine exhibition. Concurrent to the snout wipe collection, owners took the rectal temperatures of his/her pigs. In this case, 47 (2.4%) pigs tested positive for IAV before they entered the swine barn. The mean rectal temperatures differed by only 0.19°C between IAV‐positive and IAV‐negative pigs. The low prevalence of IAV among the pigs upon entry to the fair in the second objective provides evidence that limiting intraspecies spread of IAV during the fairs will likely have significant impacts on the zoonotic transmission. However, in both objectives, the high degree of similarity in the body temperature measurements between the IAV‐positive and IAV‐negative pigs made it impossible to set a diagnostically meaningful cut point to differentiate IAV status of the individual animals. Unfortunately, body temperature measurement cannot be used to accurately screen exhibition swine for IAV.  相似文献   
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