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   143篇
  免费   17篇
林业   3篇
农学   1篇
基础科学   1篇
  14篇
综合类   12篇
农作物   9篇
水产渔业   6篇
畜牧兽医   106篇
园艺   2篇
植物保护   6篇
  2023年   2篇
  2022年   1篇
  2021年   2篇
  2020年   3篇
  2019年   5篇
  2018年   5篇
  2017年   6篇
  2016年   5篇
  2015年   8篇
  2014年   2篇
  2013年   17篇
  2012年   6篇
  2011年   4篇
  2010年   8篇
  2009年   6篇
  2008年   7篇
  2007年   8篇
  2006年   3篇
  2005年   5篇
  2004年   6篇
  2003年   4篇
  2002年   3篇
  2001年   3篇
  2000年   2篇
  1999年   3篇
  1998年   6篇
  1997年   5篇
  1996年   4篇
  1995年   2篇
  1994年   4篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1990年   4篇
  1989年   2篇
  1984年   1篇
  1978年   3篇
  1976年   1篇
排序方式: 共有160条查询结果,搜索用时 15 毫秒
71.
Summary In Kuwait, approximately 12,000 diary cows were vaccinated with a reduced dose of 3×109 Brucella abortus strain 19 and approximately 350,000 sexually mature sheep and goats with a reduced dose of 107B.melitensis strain Rev. 1. Using the criteria of prevaccinal and postvaccinal incidences of antibodies, abortions, and human cases of brucellosis, the programme was very successful. Widespread vaccination of adult animals is the most effective method of controlling brucellosis among cattle, sheep and goats in many countries.
Resumen En Kuwait, se vacunaron aproximadament 12,000 vacas lecheras con una dosis reducida de 3×109 organismos deBrucella abortus cepa 19 y approximadament 350,000 ovejas y cabras sexualmente maduras fueron vacunadas con una dosis reducida de 107 organismos deB. melitensis opa Rev. 1. Utilizando los criterios prevacunales de incidencia de anticuerpos, abortos, y casos humanos de brucelosis, el programa fuvo gran exito. Ef método mas efectivo de control de la brucelosis bovina, ovina y caprina an numerosas paises es la amplia utilización de vacuna en animales adultos.

Résumé Au Kuwait, environ 12,000 vaches laitiěres ont été vaccinées avec une dose réduite de souche 19Brucella abortus (3×109) et environ 350,000 moutons et chevres qui étaient matures sexuellement, one été vaccinés avec une dose réduite de soucheB. melitensis Rev. 1 (107). Basé sur la présence d'anticorps, sur le nombre d'avortements et de cas de brucellose chez les humains avant et aprés vaccination, le programme a été un succěs. La méthode la plus effective pour contr?ler la brucellose chez les bovins, les ovins et les caprins dans beaucoup de pays et de vacciner sans exception tous les animaux adultes.
  相似文献   
72.
73.
Objective: To assess the efficacy and safety of a formulation containing moxidectin and 6 in 1 vaccine in sheep under field conditions.
Design: Efficacy and safety study.
Animals: Two hundred and five crossbred Merino lambs and two hundred and eight Merino ewes were used in the studies.
Procedure: A formulation was made for the simultaneous treatment of sheep with moxidectin and immunisation against clostridial diseases and caseous lymphadenitis. The efficacy against nematodes, vaccine response and safety were assessed.
Results: Effective control of nematodes and responses to antigens were achieved following subcutaneous administration. The formulation was safe to administer; occasional minor tissue reactions were evident, but no other adverse effects of treatment were observed in either pregnant ewes or lambs, using either the recommended dose, or an overdose of the formulation.
Conclusion: Administration of a formulation containing moxidectin, five clostridial antigens and caseous lymphadenitis antigen proved safe and efficacious under field conditions.  相似文献   
74.
Objectives of this study were to characterize patterns of follicular development in sheep superovulated with purified follicle stimulating hormone (FSH) (OVAGENTM, ICP, Auckland, New Zealand) and to determine its influence on preovulatory events (onset of the oestrus behaviour and timing of the preovulatory luteinizing hormone surge) and ovarian response (ovulation rate and embryo yield). Number and size of all ≥ 23 mm follicles from the first FSH injection to withdrawal of progestagen sponges was determined by transrectal ultrasonography just prior to every FSH injection in nine Manchega ewes superovulated with eight decreasing doses (ml) (1.5 × 3, 1.25 × 2 and 1 × 3) of OVAGEN injected twice daily from 60 h before to 24 h after the withdrawal of 40 mg fluorogestone acetate sponges. Oestrous detection and jugular blood sampling for LH radioimmunoassay were performed every 3 h from 14 to 53 h after sponge removal and ovulation rate and number of embryos were determined 4 days after progestagen withdrawal. Administration of OVAGEN induced a significant rise (p < 0.0005) in the number of follicles ≥ 4 mm in size because of an increased growth in size of follicles from the first FSH injection to sponge removal, an increase in the number of newly detected follicles from 12 to 36 h of the first FSH dose (p < 0.005) and a decrease in regression rate from 24 h (p < 0.001). The number of follicles 2–3 mm in size at first FSH dose (10.4 ± 1.5) was positively correlated with the number of ≥ 4 mm follicles at 0 h (19.0 ± 2.7, p < 0.01). A higher number of ≥ 4 mm follicles at 0 h was related with an earlier appearance of oestrus (31.5 ± 1.5 h, p = 0.08) and LH surge (45.0 ± 2.3 h, p < 0.005), and a higher ovulation rate (18.2 ± 3.8, p < 0.005). On the other hand, the rate of embryo recovery was decreased in ewes with earlier preovulatory LH peaks (p < 0.005), with a shorter interval between oestrus and LH peak (p < 0.05).  相似文献   
75.
76.
The aim of this study was to determine the association between the oestrous response of pre‐pubertal gilts to gonadotrophin injection or boar exposure and their subsequent farrowing rate and litter size. At 154 days of age, randomly selected pre‐pubertal gilts received an intramuscular injection of 400 IU equine chorionic gonadotrophin plus 200 IU human chorionic gonadotrophin (PG600®; Merck Animal Health; n = 181). From the remaining pool of animals not treated with hormones, the first gilts showing signs of oestrus were selected to act as controls (n = 201). Boar exposure began at 155 days of age for both groups, and gilts were bred at a weight of approximately 130 kg. Comparisons were made between PG600®‐treated gilts exhibiting oestrus or not within 7 days post‐injection (early and late responders, respectively) and control gilts exhibiting oestrus or not within 30 days after beginning of boar exposure (select and non‐select control gilts, respectively). By 162 days, oestrus was detected in 67.5% of PG600®‐treated gilts compared with 5.7% of control gilts (p < 0.0001). The proportion of animals observed in oestrus at least three times before breeding was greater for select control gilts compared with early and late responder PG600®‐treated gilts (p  0.001). There were no significant differences in farrowing rate and litter size between the four treatment groups. These data indicate that PG600® is an effective tool to induce an earlier oestrus in gilts, that subsequent farrowing rate and born alive litter size compare favourably to that of select gilts and that gilts failing to respond promptly to hormonal stimulation do not exhibit compromised fertility.  相似文献   
77.
To meet weekly breeding targets, it is occasionally necessary to inject exogenous gonadotrophins to induce oestrus in prepubertal gilts. However, the gilt oestrus response to equine chorionic gonadotrophin (eCG) either alone or in combination with human chorionic gonadotrophin (hCG) can be unpredictable. The objective of the present study was to examine possible reasons for this unpredictability. Prepubertal gilts (90 kg and 153 days of age, n = 109) received an injection of either 600 IU eCG or a combination of 400 IU eCG and 200 IU hCG (PG600), or were non-injected controls, and were then exposed to a mature boar for 15 min daily for 7 days for oestrus detection. At the time of injection, real-time ultrasound revealed that the gilt ovaries had primarily 1–2 mm follicles. Blood samples were obtained at time of hormone injection (day 0) and at days 3, 7 and 10 for assay of serum progesterone concentrations. The oestrus responses by 7 days were15.5%, 73.3% and 0%, for eCG, PG600, and control gilts, respectively (p < 0.001). The oestrus response improved (p < 0.05) with increasing body weight. Based on circulating progesterone levels, all oestrous gilts ovulated except for four of the PG600 gilts. Failure to express oestrus in PG600 gilts was not associated with a premature rise in progesterone.  相似文献   
78.
Five sunflower hybrids and one open-pollinated variety were sown at two locations in West Germany and at two-sowings at Giza, Egypt (summer and winter seasons). Cultivars showed different response concerning oil and protein contents as well as fatty acid composition. Highest protein content was observed from Giza in winter season. Cultivars differed significantly with this respect under different environments. However, oil content was not significantly affected by environments X cultivars interaction.
Regarding fatty acid composition, palmitic and stearic acids were insignificantly affected. However, highest oleic acid percentage (57.5%) was observed at Giza in summer sowing by Nhy , hybrid, while at Giza in winter sowing the highest value (25.7%) was produced by Semu 209 hybrid. The differences between the two Germany locations were relatively low in range from 14.6–17.6%. Concerning linoleic acid, it showed an opposite trend.
Environments X cultivars interaction showed significant influence on total tocopherol content.  相似文献   
79.
Surfactant enhanced desorption of 2,4,6-trinitrotoluene (TNT) from contaminated soils at a military site was investigated. Anionic (SDS and DOWFAX 8390), cationic (CTAC and CTAB), and nonionic (Tween 80 and Brij 35) surfactants were first tested at concentrations ranging from 0.1 to 1%. The anionic and nonionic surfactants were further tested at concentrations of up to 10%. Anionic surfactants, particularly SDS, provided the best desorption of TNT from the soil. There was not any increase in TNT desorption for both the nonionics and cationics at concentrations ranging between 0.1 to 1% and the extent of desorption was found to be lower than the TNT desorption only by water. The competition of the negatively charged soil surfaces for the positively charged cationics and the neutral nonionic surfactants may constitute the underlying reason. TNT was significantly desorbed when the concentrations of Tween 80, DOWFAX 80 and SDS were increased up to 10%.  相似文献   
80.
This study evaluated the effectiveness of synthetic and natural antioxidants, green tea, commercial grape seed extracts/combinations, and TBHQ, with varying concentrations of lipid oxidation of nonirradiated and irradiated chicken breast meats stored at 5 degrees C for 12 days. Fresh boneless and skinless chicken breast meats were vacuum-infused with varying concentrations of antioxidants: green tea, grape seed extracts alone/in combination, and TBHQ. The irradiation dosage was 3.0 kGy. Carbonyl values of raw chicken meat and thiobarbituric acid reactive substances (TBARS) values of raw and cooked chicken meat were determined for 0-12 days at 5 degrees C storage. TBARS values for 0-12 days of storage at 5 degrees C ranged from 1.21 to 7.3 and 1.22 to 8.51 mg malondialdehyde/100 g chicken for nonirradiated and irradiated raw chicken, respectively. TBARS values of cooked chicken ranged from 2.19 to 35.83 and 2.45 to 45.72 mg malondialdehyde/100 g chicken for nonirradiated and irradiated chicken, respectively. Irradiation increased TBARS values of both controls and plant extracts. The carbonyl content in meat lipid ranged from 1.7 to 2.9 and 1.7 to 4.41 micromol acetophenone/10 g of nonirradiated and irradiated chicken meat, respectively, and meat protein ranged from 1.4 to 2.07 and 1.41 to 2.72 micromol/10 g meat. Infusion of chicken meat with selected plant extracts is an effective method to minimize lipid oxidation and volatiles developments caused by irradiation.  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