全文获取类型
收费全文 | 491篇 |
免费 | 23篇 |
国内免费 | 41篇 |
专业分类
林业 | 29篇 |
农学 | 43篇 |
基础科学 | 9篇 |
39篇 | |
综合类 | 151篇 |
农作物 | 24篇 |
水产渔业 | 70篇 |
畜牧兽医 | 159篇 |
园艺 | 16篇 |
植物保护 | 15篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 16篇 |
2021年 | 16篇 |
2020年 | 10篇 |
2019年 | 17篇 |
2018年 | 15篇 |
2017年 | 22篇 |
2016年 | 7篇 |
2015年 | 22篇 |
2014年 | 25篇 |
2013年 | 32篇 |
2012年 | 24篇 |
2011年 | 30篇 |
2010年 | 15篇 |
2009年 | 25篇 |
2008年 | 27篇 |
2007年 | 24篇 |
2006年 | 32篇 |
2005年 | 26篇 |
2004年 | 22篇 |
2003年 | 26篇 |
2002年 | 41篇 |
2001年 | 24篇 |
2000年 | 15篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1972年 | 1篇 |
1962年 | 1篇 |
1926年 | 1篇 |
1925年 | 1篇 |
排序方式: 共有555条查询结果,搜索用时 31 毫秒
51.
Immunization of goats against inhibin increased follicular development and ovulation rate 总被引:4,自引:0,他引:4
Sasaki K Medan MS Watanabe G Sharawy S Taya K 《The Journal of reproduction and development》2006,52(4):543-550
In the present study, two experiments were conducted to induce superovulation in goats using passive and active immunization against inhibin. In the first experiment, two groups of goats were given an intravenous injection of either 10 ml normal goat serum (control; n=6) or inhibin antiserum developed against [Tyro30]-inhibin alpha (1-30) (passively immunized; n=6) 48 h before treatment with PGF2alpha. In the second experiment, two groups of goats were immunized with inhibin vaccine (actively immunized; n=5) or Freund's adjuvant (control; n=5) followed by three booster immunizations at 4 week intervals. Blood samples were collected for determination of FSH, LH, estradiol-17beta, and progesterone. Ultrasonography was used to determine ovarian activity at PGF2alpha injection and ovulation rate one week after estrus. In both experiments, there was a significant increase in plasma FSH concentration compared with the controls. However, the pattern of the FSH levels was different between the passively and actively immunized goats. The numbers of follicles in passively and actively immunized goats (22.4 +/- 2.3 and 18.6 +/- 2.1, respectively) were significantly greater than those in the controls (2.6 +/- 0.4 and 2.3 +/- 0.4, respectively). In addition, the ovulation rate was greater in the immunized animals compared with the controls. Therefore, either passive or active immunization against inhibin could be used to induce superovulation in goats. 相似文献
52.
53.
Korosue K Murase H Sato F Ishimaru M Harada T Watanabe G Taya K Nambo Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2012,74(8):995-1002
The purpose of this study was to demonstrate that a barren parous Thoroughbred mare with lactation induced by hormonal treatment can be introduced to an orphan foal at the same farm and that the mare can become pregnant after the end of the hormonal treatment. An additional purpose was to investigate the changes in the plasma concentrations of prolactin, estradiol-17β, progesterone, follicle-stimulating hormone, and luteinizing hormone before, during, and after hormonal treatment. The difference in body weight between the adopted foal and the control foals, which were at the same farm and raised by their natural mothers, was 17 kg at 24 weeks old, when the foals were weaned. However, the adopted foal and the control foals had almost the same weight at 35 weeks old and later. The first ovulation after hormonal treatment was confirmed 10 days after the end of hormonal treatment and then the normal estrous cycle resumed. Furthermore, the changes in plasma progesterone, estradiol-17β, follicle-stimulating hormone, and luteinizing hormone showed regular patterns after the first ovulation. Conception was confirmed in the fifth ovulation. Meanwhile, another study demonstrated that conception was confirmed in the first ovulation after hormonal treatment. The present study is the first to demonstrate the hormonal profiles during and after induction of lactation in a Thoroughbred mare. This approach is useful for solving the economic and epidemic problems of introducing a nurse mare to an orphan foal. 相似文献
54.
恩施烟区土壤磷素与烤烟磷含量的关系 总被引:1,自引:0,他引:1
分析了湖北省恩施烟区土壤磷素与烤烟磷含量的状况及其相互关系,结果表明:恩施烟区土壤磷素含量偏低,全磷和速效磷含量分别为(0.63±0.23)gkg-1和(16.88±12.73)mgkg-1,二者之间存在极显著的正相关,相关系数为0.6353**。土壤全磷和速效磷含量在不同海拔高度、土层深度之间差异显著,海拔之间表现为:高海拔中海拔低海拔;土层之间表现为:0~20cm20~40cm40~60cm。烤烟磷素含量较低,平均为(1.68±0.32)gkg-1,在不同品种、海拔之间差异显著,品种之间表现为:云烟87K326云烟85,海拔之间表现为:高海拔中海拔低海拔。烤烟磷素含量在等级之间差异不显著,但随着叶位的升高,烤烟磷含量有升高的趋势。烤烟磷含量(y)与土壤速效磷含量(x)之间存在极显著的回归关系,y=0.1224+0.0026x,相关系数r=0.8582**。土壤速效磷含量分组后,随着土壤速效磷含量升高,烤烟磷含量也呈现出升高趋势。 相似文献
55.
为了解小麦Glu-A1位点1亚基和Null亚基间的品质效应差异,用郑麦9405/郑麦98//周麦16配制杂交组合,利用系谱法辅助生化标记连续多代选择后得到纯合的1亚基和Null亚基的近等基因系,并对近等基因系1亚基和Null亚基间的面筋特性和粉质特性进行了测定和分析.结果表明,对于面筋指数、形成时间、稳定时间和粉质质量指数,1亚基的贡献明显大于Null亚基,1亚基比Null亚基的面筋指数、形成时间、稳定时间和粉质质量指数分别提高9.79%、68.73%、25.89%和13.99%,成组数据的t测验显示差异达到极显著水平(P值分别为0.007、0.000、0.002和0.006),亚基效应为1亚基>Null亚基;对于湿面筋含量、干面筋含量和吸水率,1亚基和Null亚基的贡献无明显差别,成组数据t检验显示差异不显著(0.978、0.654和0.206). 相似文献
56.
Seiichiro Yonemura Masayuki Yokozawa Gen Sakurai Ayaka W. Kishimoto-Mo Nayeon Lee Shohei Murayama Kentaro Ishijima Yasuhito Shirato Hiroshi Koizumi 《Journal of Forest Research》2013,18(1):49-59
At the Takayama deciduous broadleaved forest Asiaflux site in Japan, the ecosystem carbon dynamics have been studied for more than two decades. In 2005, we installed non-dispersive infrared CO2 sensors in the soil below the site’s flux tower to systematically study vertical soil–air CO2 dynamics and explain the behavior of soil surface CO2 efflux. Soil–air CO2 concentrations measured from June 2005 through May 2006 showed sinusoidal variation, with maxima in July and minima in winter, similar to the soil CO2 effluxes measured simultaneously using open-flow chambers. Soil–air CO2 concentrations increased with soil depth from 5 to 50 cm: from 2,000 to 8,000 ppm in the summer and from 2,000 to 3,000 ppm in the winter under snow. Summer soil–air CO2 concentrations were positively correlated with soil moisture on daily and weekly scales, indicating that the Oi, Oe, and A horizons, where decomposition is accelerated by high-moisture conditions, contributed substantially to CO2 emissions. This result is consistent with the short residence time (about 2 h) of CO2 in the soil and larger emissions in shallow soil layers based on our diffusion model. We revealed for the first time that soil–air CO2 concentrations in winter were correlated with both snow depth and wind speed. CO2 transfer through the snow was hundreds of times the gas diffusion rates in the soil. Our estimate of the CO2 efflux during the snow-cover season was larger than previous estimates at TKY, and confirmed the important contribution of the snow-cover season to the site’s carbon dynamics. 相似文献
57.
Kenji Korosue Harutaka Murase Fumio Sato Mutsuki Ishimaru Gen Watanabe Takehiro Harada Kazuyoshi Taya Yasuo Nambo 《Journal of Equine Veterinary Science》2013
The purpose of this study was to investigate the changes in serum concentrations of prolactin (PRL), progestagens, and estradiol-17β and biochemical parameters during peripartum in an agalactic mare, as well as to study the periparturient indices of the foal. A 4-year-old Thoroughbred, primiparous, pregnant mare was diagnosed as agalactic from clinical conditions such as absence of observable udder development and weight loss of her foal after parturition. Serum PRL concentrations of the agalactic mare during prepartum tended to be lower than those of the control mares (19.5 ng/mL and 67.0 ± 15.0 ng/mL on the day of parturition, respectively). The progestagens and estradiol-17β concentrations were not markedly different between the agalactic mare and the control mares. Concentrations of γ-glutamyl transferase of the agalactic mare were higher than those of the control mares (P < .05). Although the serum immunoglobulin G concentrations of the foal of the agalactic mare after 24 hours of age were lower than those of the foals of the control mares (P < .05), all periparturient indices regarding the agalactic mare were considered to be within the normal range. In contrast, insufficient udder development and milk production was observed in the agalactic mare through the pre- and postpartum periods. We have ruled out the known causes for agalactia in mares based on other parameters, clinical symptoms, and nutritional causes. Clinical symptoms and PRL parameters in this case report are consistent with the category of agalactia in mares of unexplained causes, and we have determined additional blood parameters associated with agalactia in mares that are consistent with this category. 相似文献
58.
Daisuke FUKUI Masashi NAGANO Ryohei NAKAMURA Gen BANDO Shinichi NAKATA Masao KOSUGE Hideyuki SAKAMOTO Motozumi MATSUI Yojiro YANAGAWA Yoshiyuki TAKAHASHI 《The Journal of reproduction and development》2013,59(5):491-495
Artificial insemination (AI) can help to avoid inbreeding and genetic degeneration
for sustaining genetically healthy populations of endangered species in captivity.
Collection of a sufficient quantity of viable sperm is an essential first step in the
AI process. In the present study, we examined the effects of frequent
electroejaculation on semen characteristics in a Siberian tiger. We collected semen
in all 17 trials during 6 breeding seasons (6 years). The mean number of sperm and
the percentage of motile sperm were 294.3 ± 250.2×106/ejaculate and 82.4 ±
11.4%, respectively. The number of motile sperm tended to increase during frequent
electroejaculation in the same breeding season. Semen collection by
electroejaculation can be performed effectively up to the fourth sequential
ejaculate, which contained the most sperm in the study. In conclusion, frequent
collection of sperm by electroejaculation from tigers may be effective for collection
of a large number of motile sperm. 相似文献
59.