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   132篇
  免费   8篇
林业   8篇
农学   9篇
  12篇
综合类   6篇
农作物   2篇
水产渔业   11篇
畜牧兽医   85篇
园艺   3篇
植物保护   4篇
  2022年   2篇
  2021年   5篇
  2020年   6篇
  2019年   6篇
  2018年   9篇
  2017年   2篇
  2016年   2篇
  2015年   4篇
  2014年   6篇
  2013年   10篇
  2012年   10篇
  2011年   7篇
  2010年   2篇
  2009年   7篇
  2008年   4篇
  2007年   8篇
  2006年   8篇
  2005年   5篇
  2004年   4篇
  2003年   4篇
  2002年   3篇
  2001年   3篇
  2000年   3篇
  1999年   4篇
  1995年   1篇
  1992年   1篇
  1991年   2篇
  1990年   1篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1984年   1篇
  1983年   2篇
  1982年   1篇
  1979年   1篇
  1977年   1篇
  1970年   1篇
排序方式: 共有140条查询结果,搜索用时 15 毫秒
101.
In Brazil, water buffaloes have been used to produce milk for mozzarella cheese production. Consequently, the main selection criterion applied for the buffalo genetic improvement is the estimated mozzarella yield as a function of milk, fat and protein production. However, given the importance of reproductive traits in production systems, this study aimed to use techniques for identifying genomic regions that affect the age at first calving (AFC) and first calving interval (FCI) in buffalo cows and to select candidate genes for the identification of QTL and gene expression studies. The single-step GBLUP method was used for the identification of genomic regions. Windows of 1 Mb containing single-nucleotide polymorphisms were constructed and the 10 windows that explained the greatest proportion of genetic variance were considered candidate regions for each trait. Genes present into the selected windows were identified using the UOA_WB_1 assembly as the reference, and their ontology was defined with the Panther tool. Candidate regions for both traits were identified on BBU 3, 12, 21 and 22; for AFC, candidates were detected on BBU 6, 7, 8, 9 and 15 and for first calving interval on BBU 4, 14 and 19. This study identified regions with great contribution to the additive genetic variance of age at first calving and first calving interval in the population of buffalo cows studied. The ROCK2, PMVK, ADCY2, MAP2K6, BMP10 and GFPT1 genes are main candidates for reproductive traits in water dairy buffaloes, and these results may have future applications in animal breeding programs or in gene expression studies of the species.  相似文献   
102.
Inactivated influenza virus vaccine prepared from a non-pathogenic influenza virus strain A/duck/Hokkaido/Vac-1/2004 (H5N1) from the virus library conferred protective immunity to chickens against the challenge of antigenically drifted highly pathogenic avian influenza virus (HPAIV), A/whooper swan/Hokkaido/1/2008 (H5N1). The efficacy of the vaccine was comparable to that prepared from genetically modified HPAIV strain deltaRRRRK rg-A/ whooper swan/Mongolia/3/2005 (H5N1), which is more antigenically related to the challenge virus strain, in chickens.  相似文献   
103.
104.
This study was conducted to investigate the arginine‐vasopressin (AVP)‐ and oxytocin‐induced changes in plasma adrenocorticotropic hormone (ACTH), growth hormone (GH), insulin and glucagon levels and their metabolite concentrations in goats. In this study, five goats were intravenously injected with either AVP (0.3 nmol/kg body weight (BW)) or oxytocin (0.7 IU/kg BW). AVP injection significantly increased ACTH and GH secretions compared to controls, although insulin and glucagon concentrations were not altered. The incremental areas (ICAs) of the ACTH and GH concentrations were higher in the AVP group than in the saline group. Oxytocin injections increased insulin and glucagon secretions, while ACTH level was not altered. GH levels became elevated 30 min after the oxytocin injection. The ICAs of insulin and glucagon after oxytocin was injected were higher than those of the control. Results indicate that AVP is a potent stimulant of ACTH and GH secretions, while oxytocin uses different pathways to regulate insulin and glucagon secretions in goats.  相似文献   
105.
From the two species of bivalves, Calyptogena soyoae around a cold seep and Bathymodiolus septemdierum near hydrothermal vents in the sea, sterols were isolated using high-pressure liquid chromatography analysis of the lipid fraction guided by characteristic 1H NMR signals of the sterol skeleton. The minor sterol composition of C. soyoae included 24-methylenecycloartanal, cycloeucalenol, and obutusifoliol, which are known phytosterols. From B. Septemdierum, lathosterol and cholesterol as main sterols together with more diverse sterols were obtained. The difference between these species and their sterol contents is most likely because of feeding modes and metabolism of nutrients from their habitat.  相似文献   
106.
With the ever-increasing demand in veterinary medicine to administer chemotherapy agents, it is imperative for the practitioner as well as the support staff to follow strict guidelines for the administration and disposal of cytotoxic drugs. Because of the possible reproductive risks associated with hazardous drugs, all employees who may be pregnant or trying to become pregnant should be excluded from the process. The long-term occupational effects of these agents are not known; therefore, a standard operating procedure including storage of chemotherapy drugs, protective attire, drug preparation, administration, waste disposal/management, hazardous drug spills, and emergency measures for personal contamination should be carefully implemented and documented.  相似文献   
107.
We compared the responsiveness and sensitivity to soil fumigation of DNA- and RNA-based analyses of a bacterial community. We first established an improved RNA extraction method using DNA as an adsorption competitor, because it is extremely difficult to extract nucleic acids from clay-rich volcanic ash soil (Andisol), which adsorbs nucleic acids. This novel method facilitated RNA extraction from 500 mg of Andisol for molecular analyses. Then we monitored 16S rDNA PCR and 16S rRNA RT-PCR denaturing gradient gel electrophoresis (DGGE) profiles of samples collected from a chloropicrin (CP)-treated field over 2 months. The difference between untreated control and CP-treated plots was detected clearly both in DNA- and RNA-based DGGE profiles after treatment. The temporal changes in DGGE profiles, however, differed between DNA- and RNA-based analyses in CP-treated plots. RNA-based DGGE showed quicker and greater changes in the bacterial community after CP treatment than did DNA-based DGGE, which showed similar trends to RNA-based DGGE but with a time lag. The extent of decrease in the diversity index (H′) and the change in principal response curves was larger in RNA-based analyses. These results indicate that the rDNA PCR-DGGE method also detects DNA of microbes no longer alive after fumigation, and that rRNA provides a more responsive biomarker than rDNA.  相似文献   
108.
109.
Various triterpenoid glycosides were extracted from whole unripe tomato fruits ( Lycopersicon esculentum cv. Cedrico), using aqueous 70% (v/v) ethanol to study their surfactant properties. Cation-exchange chromatography using a Source 15S column and subsequent semipreparative HPLC using an XTerra RP18 were employed to purify individual triterpenoid glycosides from the extract. The structure of the purified compounds was established by mass spectrometry and nuclear magnetic resonance spectroscopy. The furostanol glycoside tomatoside A (749 mg/kg of DW) and the glycoalkaloids alpha-tomatine (196 mg/kg of DW) and esculeoside A (427 mg/kg of DW) were the major triterpenoid glycosides present. Furthermore, minor amounts of a new dehydrofurostanol glycoside, dehydrotomatoside, were found. The critical micelle concentrations of the major triterpenoid glycosides, alpha-tomatine, tomatoside A, and esculeoside A, were determined as 0.099, 0.144, and 0.412 g/L, respectively. The results show that tomatoside A, and not the more well-known alpha-tomatine, is the predominant triterpenoidal surfactant in unripe tomato fruits.  相似文献   
110.
In this study, 714 cows from 26 dairy herds were reclassified as healthy or mastitic cows on the basis of long‐term somatic cell count (SCC) in milk. Cows with more than three consecutive lactation records of SCC from the first or second to fifth lactation, were selected, and their BoLA‐DRB3 (DRB3) alleles were identified using polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) method. Cows with an SCC of < 200 000 cells/mL in all monthly records were classified as healthy (n = 91). Cows with an SCC of > 300 000 cells/mL in two consecutive tests or four non‐consecutive tests or cows with an SCC of > 500 000 cells/mL in any one test during lactation, regardless of parity, were classified as mastitic (n = 201). Mastitic cows (n = 153) from another 40 herds were considered to be infected if bacteriological testing revealed mastitis pathogens in milk. Their DRB3 alleles were identified using PCR‐sequence‐based typing (PCR‐SBT). The differences in DRB3 allelic frequencies between healthy cows and cows with various degrees of mastitis were re‐investigated. Moreover, the associations of various amino acid motifs in DRB3 alleles with resistance or susceptibility to mastitis pathogens were re‐examined. DRB3.2*8(DRB3*1201) and DRB3.2*16(DRB3*1501) alleles were found to be associated with susceptibility, while DRB3.2*22(DRB3*1101), DRB3.2*23(DRB3*2703), and DRB3.2*24(DRB3*0101) alleles were found to be associated with resistance.  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