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41.
【目的】量化环境要素对山西省中条山油松Pinus tabuliformis人工林下物种分布影响,为进一步揭示中条山油松人工林下物种多样性维持机制提供理论依据。【方法】基于中条山油松人工林样地植物和土壤调查数据,分析环境因子对油松人工林下物种分布的影响。【结果】环境因子对灌木、草本、藤本物种分布的解释率(校正解释率)分别为45.7%(34.5%)、37.0%(20.4%)、43.4%(30.6%);油松林下物种分布主要受非生物环境影响,海拔和土壤通气性是影响该地区物种分布的关键环境因子;灌木和藤本分布主要受海拔影响,草本分布主要受土壤通气性影响,且随着海拔、土壤通气性的升高油松人工林下物种多样性下降。【结论】地形(海拔)和土壤(土壤通气性)因子对区域群落生境的关键塑造作用所形成的环境筛是影响中条山油松人工林下物种分布的关键性因子。图1表5参39 相似文献
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为揭示不同基因型烤烟的光合特性,通过大田试验,利用LI-6400XT光合测定系统测定了毕节烟区4种主栽品种上部叶片的光、CO2的响应曲线,分别利用Farquhar模型和直角双曲线模型拟合光、CO2曲线,阐述了4个品种光响应和CO2响应特征及其主要参数.结果表明,4个品种响应曲线规律基本一致,响应特征参数差异明显.云烟97对高光照的适应能力相对最强、碳同化能力也表现较好;K326则表现出对弱光和低摩尔分数CO2的利用效率,对环境适应能力较强;毕纳1号饱和CO2速率明显高于其余品种,具有一定的高产潜力;红花大金元的优势体现在自身碳同化过程中的羧化效率.高海拔区域,选择种植云烟97能发挥其适应高光照的优势;中低海拔区域,K326和毕纳1号适应性较好,且能更好地发挥其生产潜力. 相似文献
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The existence of a dominant massive planet, Jupiter, in our solar system, although perhaps essential for long-term dynamical stability and the development of life, may not be typical of planetary systems that form around other stars. In a system containing two Jupiter-like planets, the possibility exists that a dynamical instability will develop. Computer simulations suggest that in many cases this instability leads to the ejection of one planet while the other is left in a smaller, eccentric orbit. In extreme cases, the eccentric orbit has a small enough periastron distance that it may circularize at an orbital period as short as a few days through tidal dissipation. This may explain the recently detected Jupiter-mass planets in very tight circular orbits and wider eccentric orbits around nearby stars. 相似文献
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Objective To evaluate organoleptic postmortem inspection techniques for bovine livers and kidneys.
Study design At Australian export abattoirs, bovine liver and kidneys are assessed and graded by qualified meat inspectors during normal operations. Over a 12-month period at a large abattoir in eastern Australia during 1997 and 1998, a sample of these organs was reassessed independently using a range of pathological and microbiological methods. Agreement between routine inspection and independent assessment was evaluated using methods of inter-rater agreement.
Results A total of 944 livers and 1374 kidneys were included in the study. All of these organs had been classified during routine inspection. The authors examined 363 livers and 329 kidneys both grossly and histologically, including 36 livers and 14 kidneys that were also subjected to microbiological examination. All other organs were only examined grossly. There was only a moderate level of agreement between the routine and independent assessment methods. For livers, the percentage agreement was 80.2%, McNemar's test of symmetry 55.2 (3 degrees of freedom, P < 0.001) and kappa 0.63. For kidneys, the percentage agreement was 67.8%, McNemar's test of symmetry 9.9 (1df, P = 0.002) and kappa 0.35.
Conclusions The results reinforce concerns from a number of authors about organoleptic postmortem inspection. Risk assessment methodologies offer the opportunity to modify inspection techniques in a manner that is most relevant to current public health concerns. 相似文献
Study design At Australian export abattoirs, bovine liver and kidneys are assessed and graded by qualified meat inspectors during normal operations. Over a 12-month period at a large abattoir in eastern Australia during 1997 and 1998, a sample of these organs was reassessed independently using a range of pathological and microbiological methods. Agreement between routine inspection and independent assessment was evaluated using methods of inter-rater agreement.
Results A total of 944 livers and 1374 kidneys were included in the study. All of these organs had been classified during routine inspection. The authors examined 363 livers and 329 kidneys both grossly and histologically, including 36 livers and 14 kidneys that were also subjected to microbiological examination. All other organs were only examined grossly. There was only a moderate level of agreement between the routine and independent assessment methods. For livers, the percentage agreement was 80.2%, McNemar's test of symmetry 55.2 (3 degrees of freedom, P < 0.001) and kappa 0.63. For kidneys, the percentage agreement was 67.8%, McNemar's test of symmetry 9.9 (1df, P = 0.002) and kappa 0.35.
Conclusions The results reinforce concerns from a number of authors about organoleptic postmortem inspection. Risk assessment methodologies offer the opportunity to modify inspection techniques in a manner that is most relevant to current public health concerns. 相似文献
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LINDA VAN HOOGMOED DVM Diplomate ACVS JACK R. SNYDER DVM PHD Diplomate ACVS GREGORY ROBERTS DVM MS Diplomate ACVR FA YE A. HARMON 《Veterinary surgery : VS》1997,26(6):497-501
Objective —The purpose of this study was to decribe the clinical presentation, diagnostic evaluation, and surgical management of a llama with an ectopic ureter.
Animals or Sample Population —Nine-month-old female llama.
Results —The diagnostic evaluation included the use of computed tomography and an excretory ureterogram to confirm and identify the location of the ectopic ureter. Surgical management involved a unilateral nephrectomy.
Conclusions and Clinical Relevance —Computed tomography is a valuable asset to diagnose the presence and terminal location of an ectopic ureter in llamas, and nephrectomy appears to be a viable procedure to resolve the subsequent urinary incontinence. 相似文献
Animals or Sample Population —Nine-month-old female llama.
Results —The diagnostic evaluation included the use of computed tomography and an excretory ureterogram to confirm and identify the location of the ectopic ureter. Surgical management involved a unilateral nephrectomy.
Conclusions and Clinical Relevance —Computed tomography is a valuable asset to diagnose the presence and terminal location of an ectopic ureter in llamas, and nephrectomy appears to be a viable procedure to resolve the subsequent urinary incontinence. 相似文献
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E Boukouvala A Cariani GE Maes RG Sevilla V Verrez-Bagnis M Jérôme I Guarniero G Monios F Tinti FA Volckaert JM Bautista G Krey 《Journal of agricultural and food chemistry》2012,60(32):7941-7948
Overlapping external morphometric characters easily confound the flatfishes Solea aegyptiaca and Solea solea (Soleidae) in areas of the Mediterranean Sea where both species live in sympatry. This leads to uncertainties in the fisheries and marketing of the species, in addition to misinterpretations in biogeography and conservation studies. This paper describes a simple restriction fragment length-based diagnostic test that differentiates S. solea from S. aegyptiaca, as well as from other species of the Soleidae family. Furthermore, the two species living in sympatry in the Gulf of Kavala (North Aegean Sea, Greece) present significant qualitative differences in muscle fatty acid composition, a property that can also be used to distinguish the two cryptic species. 相似文献
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从近二年来已经发表或即将发表的文献来看,猪繁殖和呼吸综合征的研究已经取得了一些极为显著的进展。 相似文献
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Endometrial nitric oxide synthase activity in mares susceptible or resistant to persistent breeding‐induced endometritis and the effect of a specific iNOS inhibitor in vitro
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FA Khan TS Chenier RA Foster J Hewson EL Scholtz 《Reproduction in domestic animals》2018,53(3):718-724
Emerging research suggests that the nitric oxide system may play a role in persistent breeding‐induced endometritis (PBIE) in the mare. Differences in uterine nitric oxide (NO) levels between mares susceptible or resistant to PBIE and a dose‐dependent inhibitory effect of NO on uterine contractility have been demonstrated. The objectives of this study were to investigate the difference in total nitric oxide synthase (NOS) activity of the endometrium between susceptible and resistant mares and the effect of a specific inducible nitric oxide synthase (iNOS) inhibitor on the endometrial NOS activity in vitro. Six susceptible and six resistant mares were selected based on preset criteria and the results of an intrauterine challenge with killed spermatozoa during oestrus. Endometrial biopsy samples were collected 24 hr post‐challenge and cultured at 37°C for 24 hr in L‐arginine supplemented minimum essential medium with or without a specific iNOS inhibitor (1,400 W dihydrochloride, 1 mM). The medium and the cultured endometrial tissue were collected after 24 hr of culture and assayed for NO and total protein, respectively. Total NO content of the medium, normalized to endometrial tissue wet weight or total protein, was used as a measure of endometrial NOS activity. Non‐parametric tests were applied for statistical analysis. Susceptible mares had significantly greater endometrial NOS activity than resistant mares. The iNOS inhibitor treatment significantly reduced NOS activity in endometrial samples derived from susceptible and resistant mares. These findings provide a basis for in vivo testing of specific iNOS inhibitors as preventative or therapeutic options for PBIE in mares. 相似文献