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   315篇
  免费   9篇
林业   13篇
农学   4篇
  42篇
综合类   19篇
农作物   1篇
水产渔业   11篇
畜牧兽医   217篇
园艺   2篇
植物保护   15篇
  2024年   1篇
  2023年   2篇
  2022年   3篇
  2021年   8篇
  2020年   1篇
  2019年   3篇
  2018年   2篇
  2017年   8篇
  2016年   5篇
  2015年   4篇
  2014年   6篇
  2013年   9篇
  2012年   6篇
  2011年   15篇
  2010年   1篇
  2009年   3篇
  2008年   15篇
  2007年   18篇
  2006年   28篇
  2005年   7篇
  2004年   16篇
  2003年   15篇
  2002年   11篇
  2001年   12篇
  2000年   7篇
  1999年   7篇
  1998年   3篇
  1997年   1篇
  1995年   1篇
  1994年   2篇
  1993年   2篇
  1992年   8篇
  1991年   11篇
  1990年   12篇
  1989年   4篇
  1988年   10篇
  1987年   14篇
  1986年   11篇
  1985年   12篇
  1984年   4篇
  1983年   1篇
  1980年   1篇
  1979年   3篇
  1977年   1篇
  1975年   2篇
  1974年   2篇
  1972年   2篇
  1971年   1篇
  1965年   2篇
  1963年   1篇
排序方式: 共有324条查询结果,搜索用时 0 毫秒
141.
Pulmonary aspergillosis was discovered in apparently healthy young rabbits. Thirty-five rabbits of various ages raised in the same rabbitry were examined by histological, ultrastructural and microbiological methods. The pulmonary lesions were found only in rabbits younger than five weeks old. These lesions contained characteristically shaped hyphae surrounded by eosinophilic radiating projections--"asteroid bodies." The significance of the disease condition and the structure of the "asteroid bodies" is discussed.  相似文献   
142.
143.
144.
145.
146.
Nipradilol is an alpha(1), beta-blocker with milder side effects than other beta-blockers used in humans. In this study the effects of nipradilol were compared with those of timolol maleate in dogs. Twelve clinically normal dogs (nine mongrels, two beagles, and one Akita) were used. We applied 0.25% nipradilol or 0.5% timolol maleate drops for a period of 28 days. Intraocular pressure (IOP) was measured before and after administration on the 2nd, 4th, 7th, 14th, 21st and 28th day. Blood pressure, pulse rate and coefficient of aqueous outflow (C-value) were also measured before and after administration on the 7th, 14th, 21st and 28th day. Both nipradilol and timolol maleate significantly lowered IOP from the 2nd day to the end of the study period. Nipradilol lowered IOP to an equivalent degree to timolol maleate. There was no significant change in blood pressure and pulse rate throughout the study period with administration of nipradilol. C-value showed a significant rise from the 14th day with administration of nipradilol, while it did not show any significant change during the study period with administration of timolol maleate. The reduction of IOP by nipradilol was similar to that by an existing beta-adrenergic antagonist, timolol maleate, but nipradilol was associated with fewer systemic side effects in dogs. Nipradilol appears to be a useful drug for treatment of glaucoma in dogs.  相似文献   
147.
To clarify the involvement of excitatory and inhibitory amino acids in canine necrotizing meningoencephalitis (NME), glutamate, aspartate, taurine and gamma-aminobutylic acid (GABA) were determined in the cerebrospinal fluids (CSF) from eight NME cases and ten healthy controls. NME dogs exhibited significantly higher concentrations of glutamate and aspartate than those in controls (p<0.001 and p<0.001, respectively), while there was no difference in taurine or GABA between the two groups. When fetal canine astrocytes were cultured for 24 hr in the presence of NME-CSF, supernatant concentrations of glutamate, aspartate and taurine were significantly elevated. Simultaneously, expression of excitatory amino acid transporter 2 (EAAT2) mRNA was significantly reduced in the astrocytes without change in EAAT1 mRNA. Hence, reduced expression of EAAT2 and impaired glutamate homeostasis may contribute to the pathogenesis of NME.  相似文献   
148.
The method for evaluating soybean (Glycine max) antixenosis against the common cutworm (Spodoptera litura) was developed based on a dual-choice assay aided by a statistical analysis model. This model was constructed from the results of a dual-choice assay in which Enrei, a soybean cultivar susceptible to S. litura, was used as both a standard and a test leaf disc for 2nd–5th instar larvae. The statistical criterion created by this model enabled the evaluation of the presence of antixenosis. This method was applied to four soybean varieties, including Tamahomare (susceptible), Himeshirazu (resistant), IAC100 (resistant), and Peking (unknown), as well as Enrei. Subsequently, the degrees of antixenosis were also compared by F-test, followed by maximum likelihood estimation (MLE). According to the results, the antixenosis of Tamahomare, Himeshirazu, and IAC100 was statistically reevaluated and Peking exhibited a novel antixenosis, which was stronger for 3rd–5th instar larvae than for 2nd instar.  相似文献   
149.
1. The characteristics of melanocyte distribution in skeletal muscles in the Silky fowl were investigated in association with growth. 2. Pectoralis (PT) and iliotibialis lateralis (ITL) muscles from 1-, 3-, 5-, 10-, 20- and 30-week-old Silky males were weighed and collagen type I was detected in frozen sections immunohistochemically. 3. Melanocytes were observed in the collagen type I-immunopositive endomysium and perimysium in both muscles. 4. Image analysis indicated that the total area occupied by melanocytes in histological sections sharply decreased from 0.61% to 0.16% in PT muscle and from 1.67% to 0.33% in ITL muscle at 1 to 3 weeks, and then gradually decreased. The melanocyte area was larger in ITL muscle than in PT muscle until 10 weeks of age. 5. We concluded that the proportion of intramuscular melanocytes in the Silky fowl differs between types of muscles in the early stages of development, and it decreases with growth.  相似文献   
150.
Keratinocyte differentiation-associated protein, Kdap, is a recently identified small secretory protein that may act as a soluble regulator for the cornification and/or desquamation of keratinocytes. To clarify the role of Kdap in the terminal differentiation of keratinocytes, detailed in situ localisation of Kdap was studied using canine skin with normal, hyperplastic and neoplastic epidermis. In normal canine trunk skin, Kdap was expressed by granular keratinocytes, with polarity to the apical side of the cells, suggesting that canine Kdap is present in lamellar granules, as in humans. Expression of Kdap was widespread in the spinous layers in hyperplastic epidermis, but was undetectable in squamous cell carcinomas. These findings suggest that Kdap is closely related to the delay of terminal differentiation and/or release of cells in hyperplastic epidermis.  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