全文获取类型
收费全文 | 299篇 |
免费 | 20篇 |
国内免费 | 1篇 |
专业分类
林业 | 6篇 |
农学 | 2篇 |
11篇 | |
综合类 | 79篇 |
农作物 | 1篇 |
水产渔业 | 5篇 |
畜牧兽医 | 202篇 |
园艺 | 2篇 |
植物保护 | 12篇 |
出版年
2020年 | 6篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 10篇 |
2015年 | 7篇 |
2014年 | 7篇 |
2013年 | 30篇 |
2012年 | 7篇 |
2011年 | 11篇 |
2010年 | 4篇 |
2009年 | 15篇 |
2008年 | 14篇 |
2007年 | 8篇 |
2006年 | 17篇 |
2005年 | 13篇 |
2004年 | 8篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 4篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 9篇 |
1997年 | 9篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1993年 | 5篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1980年 | 2篇 |
1977年 | 2篇 |
1971年 | 2篇 |
1928年 | 2篇 |
1927年 | 3篇 |
1925年 | 2篇 |
1921年 | 2篇 |
1917年 | 2篇 |
1905年 | 2篇 |
1904年 | 4篇 |
1903年 | 2篇 |
1902年 | 2篇 |
1900年 | 2篇 |
1899年 | 2篇 |
1895年 | 2篇 |
1892年 | 2篇 |
1889年 | 2篇 |
排序方式: 共有320条查询结果,搜索用时 62 毫秒
1.
2.
3.
The National Academy of Sciences held a joint workshop with the Government of Tanzania last August on the potential of solar energy for the villages of that country. Costs of five solar technologies (mini-hydroelectric generators, wind, methane generation from organic wastes, photovoltaic cells, and flat-plate solar collectors) were compared with costs of diesel-generated electricity and with electricity from the national grid. Each of the five technologies is either now competitive with diesel or will be in a few years. Although the figures presented are not conclusive since they are derived from calculations rather than an actual test, the results are encouraging enough to warrant serious testing in Third World villages. 相似文献
4.
JC Ousey 《Reproduction in domestic animals》2004,39(4):222-231
The endocrine profiles in the periparturient mares are dominated by increasing concentrations of progestagens and decreasing oestrogens. These hormones are produced by precursors from the foetus, metabolized by the placenta and act primarily on the maternal uterus. The circulating concentrations of hormones in maternal plasma, generally, represent a small proportion of those metabolized by the foetus and utero-placental tissues. There is clear evidence that the foetal hypothalamo-pituitary-adrenal (HPA) axis initiates the process of foetal maturation and the hormonal cascade which culminates in parturition at term. The endocrine changes associated with abnormal pregnancy and abortion in late pregnancy are less well understood, as are the hormonal treatments needed to avert these problems. Further work is needed to establish the biological role of the various hormones present in pregnant mares and, in particular, those hormones which control myometrial quiescence. 相似文献
5.
6.
RJ Barnewall IB Marsh PMV Cusack F Galea N Sales JC Quinn 《Australian veterinary journal》2023,101(6):254-257
Bovine respiratory disease (BRD) exerts a major impact on the beef cattle industry nationally and worldwide, with a range of aetiological factors impacting its pathogenesis. Previous research has focussed on an increasing number of bacteria and viruses that have been shown to play a role in eliciting disease. Recently, additional agents have been emerging as potential contributors to BRD, including the opportunistic pathogen Ureaplasma diversum. To determine if U. diversum was present in Australian feedlot cattle and if that presence was linked to BRD, nasal swabs were collected from a cohort of 34 hospital pen animals and compared to 216 apparently healthy animals sampled contemporaneously at feedlot induction and again after 14 days on feed at an Australian feedlot. All samples were subjected to a de novo polymerase chain reaction (PCR) assay targeting U. diversum in combination with other BRD agents. U. diversum was detected at a low prevalence in cattle at induction (Day 0: 6.9%, Day 14: 9.7%), but in a significantly greater proportion of cattle sampled from the hospital pen (58.8%). When considering the presence of other BRD-associated agents, co-detection of U. diversum and Mycoplasma bovis was most common in hospital pen animals receiving treatment for BRD. These findings suggest that U. diversum may be an opportunistic pathogen involved in the aetiology of BRD in Australian feedlot cattle, in combination with other agents, with further studies are warranted to identify if a causal relationship exists. 相似文献
7.
Mariano Carossino Rudy Bauer Mark A. Mitchell Charles O. Cummings Anke C. Sthr Nobuko Wakamatsu Kimberly Harper Ingeborg M. Langohr Kendra Schultz Maria S. Mitchell Daniel K. Howe Udeni B. R. Balasuriya 《Journal of veterinary diagnostic investigation》2021,33(3):554
Toxoplasma gondii is a zoonotic protozoan pathogen that infects many endothermic vertebrates, including humans; the domestic cat and other felids serve as the definitive host. Macropodids are considered highly susceptible to toxoplasmosis. Here, we describe the clinical, pathologic, and immunohistochemical findings of an outbreak of systemic toxoplasmosis in a mob of 11 red kangaroos (Macropus rufus), with high morbidity (73%) and mortality (100%) rates. Affected animals had either severe and rapidly deteriorating clinical conditions or sudden death, which was correlated with widespread necrotizing lesions in multiple organs and intralesional T. gondii organisms identified via MIC3-specific immunohistochemistry and confirmed by REP529-specific rtPCR. Quantification of parasites demonstrated the highest parasite density in pulmonary parenchyma compared with other tissues. Our study highlights the continued importance of this severe condition in Australian marsupials. 相似文献
8.
Profile of Steroid Receptors and Increased Aromatase Immunoexpression in Canine Inflammatory Mammary Cancer as a Potential Therapeutic Target
下载免费PDF全文
![点击此处可从《Reproduction in domestic animals》网站下载免费的PDF全文](/ch/ext_images/free.gif)
PJ De Andrés S Cáceres M Clemente MD Pérez‐Alenza JC Illera L Peña 《Reproduction in domestic animals》2016,51(2):269-275
Canine inflammatory mammary cancer (IMC) has been proposed as a model for the study of human inflammatory breast cancer (IBC). The aims of this study were to compare the immunohistochemical expression of aromatase (Arom) and several hormone receptors [estrogen receptor α (ERα), estrogen receptor β (ERβ), progesterone receptor (PR) and androgen receptor (AR)], in 21 IMC cases vs 19 non‐IMC; and to study the possible effect of letrozole on canine IMC and human inflammatory breast cancer (IBC) in vitro using IPC‐366 and SUM‐149 cell lines. Significant elevations of the means of Arom Total Score (TS), ERβ TS and PR TS were found in the IMC group (p = 0.025, p = 0.038 and p = 0.037, respectively). Secondary IMC tumours expressed higher levels of Arom than primary IMC (p = 0.029). Non‐IMC PR‐ tumours contained higher levels of Arom than non‐IMC PR+ tumours (p = 0.007). After the addition of letrozole, the number of IMC and IBC cells dropped drastically. The overexpression of Arom found and the results obtained in vitro further support canine IMC as a model for the study of IBC and future approaches to the treatment of dogs with mammary cancer, and especially IMC, using Arom inhibitors. 相似文献
9.
Clayton T Larue Joel E Ream Xuefeng Zhou Farhard Moshiri Arlene Howe Michael Goley Oscar C Sparks Steven T Voss Erin Hall Christine Ellis Janice Weihe Qungang Qi Daniela Ribeiro Xiaoping Wei Shirley Guo Artem G Evdokimov Marguerite J Varagona James K Roberts 《Pest management science》2020,76(3):1031-1038
10.
Howe Alexander A. Landhäusser Simon M. Burney Owen T. Long James N. Mock Karen E. 《New Forests》2020,51(2):367-378
New Forests - In seedling-based reforestation operations, seed source is known to be an influential variable affecting outplanting success. Adaptive variation among seed sources may also be an... 相似文献