全文获取类型
收费全文 | 613篇 |
免费 | 42篇 |
专业分类
林业 | 13篇 |
农学 | 11篇 |
45篇 | |
综合类 | 133篇 |
农作物 | 8篇 |
水产渔业 | 8篇 |
畜牧兽医 | 407篇 |
园艺 | 8篇 |
植物保护 | 22篇 |
出版年
2022年 | 6篇 |
2021年 | 6篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 7篇 |
2016年 | 10篇 |
2015年 | 10篇 |
2014年 | 18篇 |
2013年 | 30篇 |
2012年 | 16篇 |
2011年 | 27篇 |
2010年 | 11篇 |
2009年 | 14篇 |
2008年 | 30篇 |
2007年 | 30篇 |
2006年 | 12篇 |
2005年 | 13篇 |
2004年 | 14篇 |
2003年 | 25篇 |
2002年 | 10篇 |
2001年 | 13篇 |
2000年 | 12篇 |
1999年 | 13篇 |
1998年 | 9篇 |
1997年 | 10篇 |
1996年 | 8篇 |
1995年 | 9篇 |
1994年 | 8篇 |
1993年 | 12篇 |
1992年 | 15篇 |
1991年 | 9篇 |
1990年 | 20篇 |
1989年 | 11篇 |
1988年 | 8篇 |
1987年 | 12篇 |
1986年 | 15篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 12篇 |
1982年 | 9篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1975年 | 5篇 |
1974年 | 9篇 |
1973年 | 8篇 |
1972年 | 8篇 |
1971年 | 8篇 |
1970年 | 8篇 |
1969年 | 5篇 |
1960年 | 4篇 |
排序方式: 共有655条查询结果,搜索用时 31 毫秒
131.
Yan Shi David H. Byrne David Wm. Reed Richard H. Loeppert 《Journal of plant nutrition》2013,36(6):1039-1046
For dicots, bicarbonate (HCO3‐) is regarded as a main factor in the induction of iron (Fe) chlorosis in calcareous soils, and sand and solution culture. In sand culture experiments, peach [Prunus persica (Batsch) L.] rootstock developed chlorosis only when HCO3‐ levels were equal to or higher than 6 mM. Above this level, chlorosis increaeed as HCO3‐ level was increased. In spite of the lack of chlorosis at to or below 6 mM of HCO3‐, large growth reductions (40–60% reduction in fresh shoot weight) were seen in all rootstocks, although the tolerant rootstock had less reduction than the more susceptible rootstocks. Shoot growth was affected by HCO3‐ more than was root growth. 相似文献
132.
Recent attempts to address land degradation have seen calls for greater integration of scientific expertise with local knowledges. In this paper we investigate the potential for such combined understandings to enhance the accuracy, coverage and relevance of land degradation assessment. We followed a participatory approach, using methods from a variety of disciplines, to elicit potential land degradation indicators from communities in Botswana and Swaziland. These indicators were then assessed according to local and scientific understandings. We noted a significant overlap between scientific and local knowledges about land degradation in most instances. Where discrepancies occurred, the integrated participatory approach we used allows appropriate explanation to be reached, supporting the case that such an iterative process can lead to both accurate and relevant monitoring of land degradation. However, the incorporation of integrated knowledges into national policy has not been widespread in either country, suggesting that much greater efforts are required to institutionalise participatory land degradation assessment methodologies. Powerful, often neo‐Malthusian narratives of degradation continue to dominate policy discourse and limit the extent to which hybrid combined local and scientific knowledges can enhance land degradation assessment on a national and regional scale. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
133.
134.
Treatment of atrial fibrillation in horses by intravenous administration of quinidine 总被引:1,自引:0,他引:1
W W Muir S M Reed S M McGuirk 《Journal of the American Veterinary Medical Association》1990,197(12):1607-1610
Intravenous administration of quinidine gluconate converted atrial fibrillation (AF) to sinus rhythm in 9 of 12 horses. Twelve horses that were diagnosed by ECG to have AF were administered up to 11 mg of quinidine gluconate/kg of body weight in 1.0- to 1.5-mg/kg bolus injections every 10 to 15 minutes. The total dose of quinidine administered IV ranged from 1.8 to 5.8 g. Increased ventricular rate, apprehension, and mild depression were observed during treatment. Other signs of toxicosis were not observed. One horse was successfully treated with IV administered quinidine gluconate on 3 occasions. Intravenous administration of quinidine is a safe and effective alternative for treatment of AF in some horses. 相似文献
135.
R A Nicholas N E Reed G W Wood C N Hebert J C Muskett D H Thornton 《Research in veterinary science》1985,38(2):189-192
Four different oil emulsion infectious bursal disease virus (IBDV) vaccines were inoculated into four-week-old specific pathogen-free chickens. At weekly intervals for five weeks, sera were obtained from the vaccinated birds and from uninoculated control birds and examined for antibodies against IBDV by enzyme-linked immunosorbent assay (ELISA), the quantitative agar gel precipitin (QAGP) test and the virus neutralisation (VN) test. There was a highly significant correlation between the mean responses to all tests; the highest correlation (0.818) was between VN and QAGP and the lowest (0.573) between QAGP and ELISA. Generally the ELISA detected positive sera earlier than the VN test which in turn was more sensitive than the QAGP test. The ELISA and QAGP test were less variable, more reproducible and easier to perform than the VN test. 相似文献
136.
Light microscopic and ultrastructural characterization of cells recovered by respiratory-tract lavage of 2- and 6-week-old chickens 总被引:1,自引:0,他引:1
This study characterized the cell population recovered by respiratory-tract lavage of 57 two-week-old and 59 six-week-old specific-pathogen-free chickens as a prerequisite to study the response of the avian respiratory tract to infectious agents. The respiratory tract of each bird was lavaged through the trachea with a series of three lavages of 10 ml of room-temperature, neutral phosphate-buffered saline per lavage. The three lavages per bird were pooled for analysis. Total recovery volumes were measured, lavage fluid cellularity was determined, and a 200-cell differential count of non-erythrocyte cells was performed. Lavage fluid recovery was greater from 2-week-old birds (91.3 percent) than from 6-week-old birds (86.3 percent). Total cells recovered were greater for 6-week-old chickens (6.79 x 10(5)) than for 2-week-old chickens (5.03 x 10(5)). Cells of epithelial origin included squamous cells, goblet cells, and both ciliated and non-ciliated columnar epithelial cells. Cells of non-epithelial origin consisted of heterophils, lymphocytes, macrophages, eosinophils, basophils, and erythrocytes. Cells of epithelial origin were the predominant cell type recovered from the 2-week-old chickens, followed by heterophils. In 6-week-old chickens, heterophils were the predominant cell type recovered, followed by cells of epithelial origin. In descending order of prevalence, the remainder of cell types recovered from chickens of both ages were lymphocytes, macrophages, eosinophils, and basophils. 相似文献
137.
J A Angell J N Shively R E Merideth R E Reed K C Jamison 《Journal of the American Veterinary Medical Association》1985,187(2):167-169
Enucleation of the right eye was performed on a 12-year-old male Persian cat when therapy for uveitis failed. Histologic examination of the anterior and posterior chambers and the vitreous led to a diagnosis of endophthalmitis caused by Coccidioides immitis infection. The primary focus of infection was not determined. Latex particle agglutination, agar gel immunodiffusion, and complement fixation gave negative results for Coccidioides immitis antibody. 相似文献
138.
139.
140.
David Sisson DVM William P. Thomas DVM John Reed MS DVM Clarke E. Atkins DVM Howard B. Gelberg DVM PhD 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1993,7(6):364-369
Intrapericardial cysts were identified as the cause of impaired cardiac filling in six young dogs. Pneumo-pericardiography and two-dimensional echocardiography showed the cysts in 2 of 2 dogs and in 4 of 4 dogs, respectively. One dog, which was also infected with heartworms, died before surgical excision of the cyst could be performed. In the remaining dogs, surgical excision of the cysts and subtotal pericar-diectomy was successfully accomplished. Histologic examination of the excised tissue from one dog suggested that it was a pericardial coelomic cyst. The gross and histologic characteristics of the cysts removed from the other five dogs resembled those of acquired cystic hematomas. The etiopathogenesis of these cysts was uncertain, but all cysts were connected to a fatty pedicle of tissue. In one dog, a stalk of tissue was observed to enter the pericardium through a small peritoneopericardial diaphragmatic hernia. In four dogs, the stalk of tissue was adhered to the apex of the parietal pericardium. These observations suggested that intrapericardial cysts, in some dogs, develop in association with, and possibly as a result of, congenital herniation and entrapment of omentum or a portion of the falciform ligament into the pericardial sac. (Journal of Veterinary Internal Medicine 1993; 7:364–369. Copyright © 1993 by the American College of Veterinary Internal Medicine.) 相似文献