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   76篇
  免费   3篇
林业   6篇
农学   5篇
  6篇
综合类   4篇
农作物   19篇
水产渔业   13篇
畜牧兽医   24篇
园艺   1篇
植物保护   1篇
  2023年   1篇
  2022年   1篇
  2021年   4篇
  2020年   5篇
  2019年   3篇
  2018年   4篇
  2017年   5篇
  2016年   2篇
  2015年   2篇
  2014年   1篇
  2013年   7篇
  2012年   2篇
  2011年   8篇
  2010年   8篇
  2009年   5篇
  2008年   2篇
  2007年   4篇
  2006年   3篇
  2005年   4篇
  2004年   2篇
  2003年   1篇
  2002年   2篇
  2000年   1篇
  1997年   1篇
  1971年   1篇
排序方式: 共有79条查询结果,搜索用时 15 毫秒
41.
Growth performance, carcass characteristics, post-slaughtering and haematological parameters of Kivircik and Karacabey Merino male lambs in conventional and organic management systems were compared. The animals which were weaned at 7 weeks of age were divided into Kivircik conventional, Kivircik organic (KO), Karacabey Merino conventional and Karacabey Merino organic (MO) groups containing 12 lambs each. Fattening was ended when lambs attained 35 kg of live weight. The time to attain the determined fattening weight was significantly different among the groups, and Merino lambs having higher live weight gain were earlier than Kivircik lambs (p?相似文献   
42.
43.
The principles that the auditory cortex uses to decipher a stream of acoustic information have remained elusive. Neural responses in the animal auditory cortex can be broadly classified into transient and sustained activity. We examined the existence of similar principles in the human brain. Sound-evoked, blood oxygen level-dependent signal response was decomposed temporally into independent transient and sustained constituents, which predominated in different portions-core and belt-of the auditory cortex. Converging with unit recordings, our data suggest that this spatiotemporal pattern in the auditory cortex may represent a fundamental principle of analyzing sound information.  相似文献   
44.
45.
  • 1. The coralligenous habitat was studied at the large Mediterranean scale, by applying a standardized, non‐destructive photo‐sampling protocol, developed in the framework of the CIGESMED project.
  • 2. The results provided evidence to support the following statements: (a) the assemblage pattern is not homogeneously distributed across the four Mediterranean ecoregions studied (biotic gradients hypothesis); and (b) the assemblage pattern does not change significantly when the information is aggregated to higher taxonomic levels (taxonomic sufficiency hypothesis).
  • 3. Surrogate taxonomic categories higher than species, such as genus and family, can be used to reveal the multivariate pattern of the coralligenous assemblages.
  • 4. Although preliminary at the pan‐Mediterranean scale, these outcomes set the scene for future comparisons as more data sets become available but also for comparisons between taxonomic and functional patterns.
  相似文献   
46.
The effects of different levels of illumination on common dentex Dentex dentex (L.) larvae have been examined. Illumination affected the relationships between total length and digestive tube length, total length and oil globule volume, and total length and yolk sac. The relationship between total length development and yolk sac utilization in dark and light conditions was found to be significant (P<0.05). However, it was determined that the relationship between digestive tube development and oil globule absorption was not significant (P>0.05). Besides, there is no effect of different light intensities on absorption of yolk sac and oil globule and digestive tube development (P>0.05). In addition, total length development was not significant (P>0.05). Survival rate was found to be not significantly different in dark conditions (P>0.05).  相似文献   
47.
Embryonic development of common dentex (Dentex dentex) was investigated at nine different constant water temperatures (8°C, 10°C, 12°C, 14°C, 16°C, 18°C, 20°C, 22°C and 24°C). The observed effects were compared using of regression analysis. Constant water temperatures between 12°C and 18°C were found to support successful embryonic development. A negative relationship between the rate of embryonic development and incubation temperature was observed. While embryonic development was completed within this range (12°C–18°C), there was no cell division at water temperatures of 8°C and 24°C. Total mortalities were observed at the 128 cleavage stage at a temperature of 10°C, and after the beginning of gastrulation at 20°C and 22°C.  相似文献   
48.
ABSTRACT

Salix anatolica Ziel. & D. Tomasz., belonging to Salicaceae family, is endemic to the East Mediterranean in Turkey. Its threat category has been assessed as vulnerable based on the red list criteria of IUCN. Therefore, it is necessary to protect and reproduce. Within the scope of this study, propagation of the species is carried out by cutting which is one of the vegetative propagation methods. Under greenhouse media conditions, effects of different concentrated doses of auxins were examined on rooting percentage (RP), number of roots (RN) per rooted cuttings, and root length (RL) related to male and female stem cuttings. At the end of this study, the highest RP in the cuttings taken from the female individuals was 100% in Control and IAA 1000 ppm treatments, this value was also obtained as 100% in Control + Wounding and IAA 1000 ppm treatments in the cuttings taken from the male individuals. While hormone applications were effective on the RP in male individuals, they were effective on the RN and RL in female individuals. In addition, wounding has had a positive effect on both male and female individuals.  相似文献   
49.
The effect of twist level on the mechanical and thermal properties of nylon 66 and polyethylene terephthalate (PET) tyre cords has been studied. Effects of the twist on some critical cord properties such as tensile properties, shrinkage, shrink force, adhesion and fatigue have been evaluated. Breaking strength was decreased between 3.1 and 7.3 twist factor values, whereas breaking elongation was increased, on both nylon 66 and polyester cords. The tensile behaviour of high twist factor PET is similar to that of low twist factor nylon cords. This is an advantage for the possibility to get closer the properties of different materials by adjusting theirs twist factors. The shrinkage values increase with increasing twist factor, whereas shrinks force values decrease for greige nylons and polyester cords. Adhesion and fatigue resistance is increased with increasing twist factors.  相似文献   
50.
Unlike most domestic livestock species, sheep are widely known as animals with marked seasonality of breeding activity. The annual cycle of the daily photoperiod has been identified as the determinant factor of this phenomenon, while environmental temperature, nutritional status and social interactions may modulate it. The aim of this paper is to review the current state of knowledge of reproductive seasonality in sheep. Following general consideration of the importance of seasonal breeding as a reproductive strategy for the survival of the species, the paper describes manifestations of seasonality in both the ram and the ewe. Both determinant and modulating factors are discussed, and special emphasis is given to the neuroendocrine base of photoperiodic regulation of seasonal breeding. Other aspects such as the role of melatonin, the progestogens and ram effects with or without anestrus period are also reviewed.  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