首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   21篇
  免费   4篇
  国内免费   2篇
农学   2篇
  3篇
综合类   9篇
农作物   1篇
水产渔业   2篇
畜牧兽医   7篇
园艺   1篇
植物保护   2篇
  2021年   1篇
  2020年   2篇
  2019年   3篇
  2018年   1篇
  2017年   3篇
  2015年   2篇
  2014年   1篇
  2013年   2篇
  2012年   2篇
  2011年   1篇
  2009年   3篇
  2006年   1篇
  2002年   1篇
  2001年   1篇
  1999年   1篇
  1995年   1篇
  1990年   1篇
排序方式: 共有27条查询结果,搜索用时 31 毫秒
11.
为探索试验用Hartley豚鼠的饲养及建立滴鼻剂变应性鼻炎(AR)模型的有效方法,本试验采用单因素试验,考察了试验动物种类、饲养方式、卵清蛋白(OVA)致敏剂量、时间对滴鼻剂AR建模的影响,观察空白组与模型组Hartley豚鼠过敏反应症状和鼻黏膜病理切片。结果显示,就滴鼻剂的AR试验而言,Hartley豚鼠是较好的试验动物;饲料为普通小鼠饲料+莴苣叶或油麦菜;OVA为致敏剂,基础致敏浓度为0.1~0.3 mg/mL OVA,隔天腹腔注射1次,共7次;激发致敏浓度为2%,两侧鼻腔各10~30 μL,每天1次,6~9 d后与空白组相比,模型组Hartley豚鼠有明显的过敏反应症状和鼻黏膜病变。该建模方法简单经济,重现性好,可作为滴鼻剂AR建模的最佳方法。  相似文献   
12.
Temperature during grain ripening has been shown to affect amylose content and gelatinization temperature of rice starch (1–6). These studies demonstrated that high ambient temperature results in lower amylose content and higher gelatinization temperature of the starch. Rice starches obtained from rice grains that matured at lower temperature had higher iodine blue values and were more susceptible to alkali digestion than those that ripened at higher temperature.  相似文献   
13.
目的 观察不同浓度密蒙花滴眼液对去势雄兔角结膜干燥症泪腺细胞炎症因子TNF-α、IL-1β的影响,并探讨其疗效。方法 将42只雄兔随机分为:空白组(A),模型组(B),密蒙花滴眼液低(C)、中(D)、高(E)浓度组,安慰剂组(F),睾酮组(G),每组6只。除A组外各组切除双侧睾丸及附睾。术后第3天开始C-F组给予滴眼液,3次/d;G组注射丙酸睾酮,每3天1次。各组术前和术后第4周各测量一次SIT和BUT。4周后处死兔子,摘取双眼泪腺,采用免疫组化法检测泪腺中TNF-α和IL-1β,并进行统计学分析。结果 (1)SIT与BUT:B、F组前后比较,B组与其他各组及C组与D、E、G组比较,差异均有统计学意义(P<0.01)。(2)治疗后各组TNF-α、IL-1β比较:B、F组与其他各组比较,差异有统计学意义(P<0.01);C组与D、E、G组比较,差异均有统计学意义(P<0.05)。(3)TNF-α、IL-1β表达结果:A、G组未见表达;B、F组大量表达于细胞膜和细胞浆中,呈棕黄色颗粒;C、D、E组散见表达。结论 密蒙花滴眼液具有与雄激素相似的抑制炎症因子TNF-α和IL-1β表达的作用,但弱于雄激素。密蒙花滴眼液中、高浓度作用无明显差异,但均较低浓度要优。  相似文献   
14.
1. The purpose of this work was to support decision-making in poultry farms by performing automatic early detection of anomalies in egg production.

2. Unprocessed data were collected from a commercial egg farm on a daily basis over 7 years. Records from a total of 24 flocks, each with approximately 20 000 laying hens, were studied.

3. Other similar works have required a prior feature extraction by a poultry expert, and this method is dependent on time and expert knowledge.

4. The present approach reduces the dependency on time and expert knowledge because of the automatic selection of relevant features and the use of artificial neural networks capable of cost-sensitive learning.

5. The optimum configuration of features and parameters in the proposed model was evaluated on unseen test data obtained by a repeated cross-validation technique.

6. The accuracy, sensitivity, specificity and positive predictive value are presented and discussed at 5 forecasting intervals. The accuracy of the proposed model was 0.9896 for the day before a problem occurs.  相似文献   

15.
烷基聚葡糖苷液滴在黄瓜叶面的润湿状态及动态铺展行为   总被引:1,自引:0,他引:1  
为了探究烷基聚葡糖苷(alkyl polyglycosid,APG)在黄瓜叶面的动态润湿行为及其动态接触角变化规律,采用表面张力与接触角测量仪测量了一次去离子水和9种质量百分数APG水溶液(14.35%~85.78%)的表面张力、液滴叶面接触角与动态接触角、前进角与后退角、铺展直径等动态润湿参数。依据Tanner法则对接触角滞后现象、铺展驱动力成因进行分析和推测,并应用幂次法则拟合了铺展直径与幂值和时间的关系曲线。结果表明,9种APG水溶液的表面张力介于27.96~29.73 m N/m小幅范围内,而接触角却在11.35°~34.20°较大范围内变化;接触角滞后性(Δθ=46.89°)较大,反映出一次去离子水在活体植物黄瓜叶面的接触角变化符合粗糙表面上接触角滞后现象的基本规律;各质量百分数APG溶液的动态接触角在前1 s内急速下降,在之后1~10 s平稳减小并渐趋于稳定;APG在黄瓜叶面的铺展直径与时间的关系均较好地符合幂次法则,据此推测动态表面张力是黄瓜叶面(界面)占据绝对优势的铺展驱动力。  相似文献   
16.
最早对脂滴的研究可以追溯到19 世纪,Richard Altmann 和E.B. Wilson 都描述了细胞 中的脂肪滴,并推测了它们的起源(Altmann, 1890;威尔逊,1896)。早期,脂滴的高衍射特性为其 鉴定提供了便利的光学条件。20 世纪初,由于它们被认为是大多数细胞的组成部分,这种细胞 器被称为脂质体。然而,在20 世纪60 年代末,人造脂质体被发明出来,并很快取代了这个名 字。从那时起,这种细胞器被有过许多名称,包括脂滴、脂体、脂体、脂滴和脂质体。在植物中, 它们通常被称为油体。随着这一领域的迅速发展,它似乎已经定名为“脂滴”。几十年来,除了 形态学研究,脂滴的其他方面几乎没有受到关注。1991 年,脂肪细胞中与脂滴相关的磷酸蛋白 perilipin 的发现,引起人们对这种细胞器的新关注。从那时起,关于脂滴的论文数量急剧增加, 关于脂滴的功能也逐渐被重视起来。  相似文献   
17.
AIM: To investigate the inhibitory effect of Co-SZ eye drops on apoptosis of lens epithelial cells (LEC) induced by H2O2 and to study the cellular and molecular mechanisms.METHODS: (1) All lenses of Sprague-Dawley rats were incubated with H2O2 and Co-SZ eye drops.The apoptosis rates of LEC were determined by TUNEL method.The changes of LEC ultrastructure and the formation of apoptotic body were observed by electron microscopy.(2) Bovine LEC were incubated with H2O2 and Co-SZ eye drops.The inhibitory of LEC apoptosis was detected by MTT after incubation.The changes of fractional DNA content in LEC were detected by flow cytometry (FCM).[Ca2+]i , cAMP and cGMP of LEC were determined by spectrofluoremeter and radioimmunoassay, respectively.RESULTS: The LEC apoptosis rates in Co-SZ eye drops group were decreased significantly compared with H2O2 group by TUNEL.The ultrastructure changes in LEC of Co-SZ eye drops group were lighter than that in H2O2 group.The LEC apoptosis rates of Co-SZ eye drops group were dose-dependently decreased significantly compared with H2O2 groups via MTT assay.LEC apoptosis induced by H2O2 was inhibited by Co-SZ eye drops, and showing dose-dependent.The DNA contents in LEC of Co-SZ group were increased.The [Ca2+]i and cAMP in Co-SZ group were decreased obviously.The cGMP was increased.CONCLUSION: The LEC apoptosis induced by H2O2 was inhibited by Co-SZ eye drops.The mechanism of apoptosis inhibition by Co-SZ eye drops maybe contribute to the increase in DNA content.The signal transduction mechanisms are related to the decrease in [Ca2+]i and cAMP and the increase in cGMP.  相似文献   
18.
19.
20.
油茶开花习性的观察研究   总被引:4,自引:1,他引:3  
对油茶Camellia oleifera花期变异、授粉习性、落花落果过程及其影响因子的多年多点试验研究表明:①影响油茶花期因子有遗传因子和气候因子,前者决定花期类型,如早、中、晚花类型,性状稳定;气候因子主要是9月平均气温决定“入秋”早迟和花期早迟,进而影响授粉条件和次年产量。②油茶自花不孕.辅助授粉坐果率普遍高于自然授粉,随着花期推迟两者差距越大,说明开花授粉受花期气候和授粉媒介双重影响。不同单株间双列交配,出现一些平均坐果率高的母本、父本植株和坐果率高的特殊交配组合.说明单株间花粉活力和交配亲和力存在差异。③油茶花期长,在正常情况下,花后10d开始落花,高峰在花后30d内。早、中花类开花时气温高,花期集中,坐果率高,落花也集中:晚花类相反.花期长,坐果率低。落花分散。3—10月为落果期,前期落果主要为受精不良、胚珠发育停滞;8-10月为后期落果高峰期,落果数可占总落果量的50%,对产量影响极大,主要是病害引起。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号