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   54篇
  免费   7篇
林业   5篇
农学   2篇
  4篇
综合类   4篇
农作物   7篇
水产渔业   14篇
畜牧兽医   21篇
园艺   3篇
植物保护   1篇
  2022年   1篇
  2021年   4篇
  2020年   1篇
  2019年   3篇
  2018年   7篇
  2017年   2篇
  2016年   2篇
  2015年   2篇
  2014年   4篇
  2013年   3篇
  2011年   2篇
  2010年   3篇
  2009年   1篇
  2008年   1篇
  2007年   3篇
  2006年   2篇
  2005年   1篇
  2004年   2篇
  2002年   1篇
  2001年   1篇
  2000年   1篇
  1999年   2篇
  1997年   1篇
  1996年   1篇
  1993年   1篇
  1991年   1篇
  1989年   1篇
  1985年   1篇
  1981年   2篇
  1978年   2篇
  1976年   2篇
排序方式: 共有61条查询结果,搜索用时 19 毫秒
1.
The aqueous extract of the Cocculus hirsutus aerial parts (100 and 200 mg/kg, p.o.) showed significant diuretic activity and laxative effect in rats. The acute toxicity, orally evaluated in mice, was found to be higher than 3000 mg/kg.  相似文献   
2.
3.
The effects of extender composition, cryoprotectant concentration and freezing and thawing on the fertilization efficiency of cryopreserved spermatozoa of Puntius gonionotus were evaluated. Computer‐aided motility analysis of semen was conducted to check the suitability of spermatozoa for cryopreservation after mixing with different extenders and cryoprotective agents (CPAs). Extender‐4 with an osmolality 260 mOsmol kg−1and pH 7.6 was used for the cryopreservation study. Among the CPAs, dimethyl sulphoxide (DMSO) was least toxic and more than 60% fertilization was achieved when used at 1.4 M at 0 °C for 10 and 30 min, whereas the toxicity of all CPAs to spermatozoa was evident when tested at 30 °C. Semen frozen at −16 °C min−1 with 1.4 M DMSO showed 70% fertilization, which was significantly higher (P<0.05) than other freezing rates. Samples thawed at 35 °C water showed a fertilization rate comparable with that of fresh semen. Computer‐assisted semen analysis of fresh and frozen semen after thawing showed variations in different types of motility in spermatozoa and in their class. There was no significant difference in motility before or after cryopreservation; however, significant differences could be observed in the average path velocity (VAP), straight line velocity (VSL) and curve linear velocity (VCL). Semen of silver barb could be cryopreserved with extender‐4 by addition of 1.4 M DMSO to a final cryopreservation medium (MED 2) cooled at a rate of −16 °C min−1, stored in liquid nitrogen (−196 °C) and utilized after thawing at 35±2 °C.  相似文献   
4.
DARPP-32, a dopamine- and adenosine 3',5'-monophosphate (cAMP)-regulated phosphoprotein (32 kilodaltons in size), is an obligate intermediate in progesterone (P)-facilitated sexual receptivity in female rats and mice. The facilitative effect of P on sexual receptivity in female rats was blocked by antisense oligonucleotides to DARPP-32. Homozygous mice carrying a null mutation for the DARPP-32 gene exhibited minimal levels of P-facilitated sexual receptivity when compared to their wild-type littermates. P significantly increased hypothalamic cAMP levels and cAMP-dependent protein kinase activity. These increases were not inhibited by a D1 subclass dopamine receptor antagonist. P also enhanced phosphorylation of DARPP-32 on threonine 34 in the hypothalamus of mice. DARPP-32 activation is thus an obligatory step in progestin receptor regulation of sexual receptivity in rats and mice.  相似文献   
5.
This article examines the efforts by the Northwest Treeplanters and Farmworkers United union to organize Mexican migrant farmworkers in the Willamette Valley. It focuses on the union's 1995 organizing campaign of strawberry picker?s, the largest campaign in the history of Pacific Northwest agriculture. To provide context for the union's efforts, the article develops the historical role and changing nature of Oregon agriculture, sketches the politics of agriculture in the state, and describes the industry's labor system. The article concludes that significant gains for strawberry pickers were made during the 1995 campaign; the long-term consolidation of those gains remains to be demonstrated.  相似文献   
6.

Relationship of scrotal bifurcation or splitness with breeding soundness traits was investigated in 15 Beetal bucks (17–20 months of age and 48.72?±?1.57 kg mean BW). Breeding soundness traits of conjoined/unsplit (n?=?6) scrotal bucks was compared with split (n?=?9) scrotal bucks having lengthwise >?1 in. bifurcation. Two consecutive semen ejaculations per buck were collected at monthly interval during summer season (April to June 2018) using intact buck as teaser and sexual behavior was simultaneously recorded. Scrotal morphometry parameters, i.e., scrotal circumference, scrotal volume, scrotal skin thickness, testis length, width, and thickness were also recorded. Bucks with split scrotum had relatively more scrotal dimensions (scrotal circumference (P?<?0.01), scrotal volume (P?<?0.01), testis length (P?<?0.01)) than conjoined scrotal bucks. Among various semen attributes, semen volume of first ejaculate (P?<?0.01), second ejaculate (P?<?0.05), mean semen volume (P?<?0.01), total sperm count of first ejaculate, and mean sperm count of both ejaculates were more (P?<?0.01) in split scrotal bucks. However, scrotal bifurcation had no influence on sexual behavior of bucks. It is concluded that Beetal bucks with split scrotum had relatively better breeding efficiency traits than conjoined scrotal bucks.

  相似文献   
7.
SUMMARY Repeated scouring and soiling of the breech region with faeces rendered mulesed, Merino sheep susceptible to breech strike. Anthelmintic treatment of ewes before and after lambing and of lambs 6 to 8 weeks old reduced intestinal trichostrongylosis, scouring and consequent breech strike. Wether lambs tended to be more susceptible than ewe lambs and sheep grazing long pastures were struck more frequently than those on short pastures.  相似文献   
8.
9.
Sera from hosts infected with a variety of nematodes were examined for the presence of antibodies against nematode acetylcholinesterase (AChE). Antibodies were detected in the serum from hosts infected with Oesophagostomum spp., Ostertagia spp. and Trichostrongylus spp., but not in serum from hosts infected with Cooperia pectinata or Haemonchus spp., Toxocara spp. or Trichuris vulpis. In those infections in which anti-AChE antibodies were found, some individual animals failed to produce detectable antibodies. The enzyme appeared to possess antigenic specificity at the genus but not the species level.  相似文献   
10.
The immune response to mixed whole cell antigens of Aeromonas hydrophila, Edwardsiella tarda and Pseudomonas fluorescens, the common Gram negative bacterial pathogens associated with diseases of Indian major carps were evaluated for their efficacy in triggering antibody responses in rohu, Labeo rohita (Ham.). The rohu yearlings were either immunized with antigens from single bacterial strain, A. hydrophila, E. tarda and P. fluorescens or a combination of all three. An antibody response was detected at 1st week post immunization that rose significantly (p<0.05) at 4th week post immunization in all the immunized groups. The antibody level started declining after 8th week but persisted up to 10th week post immunization in all the immunized groups. Similarly, no significant difference (p>0.05) in the antibody level was found between groups immunized with single and mixed bacterial antigens. Moreover, the use of mixed bacterial antigens did not jeopardize the specific immune response to the vaccine components. Upon challenge with single pathogen, a high relative percent survival was recorded in the group immunized with mixed bacterial antigens and was comparable to those fish immunized with the single bacteria.  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