全文获取类型
收费全文 | 632篇 |
免费 | 27篇 |
专业分类
林业 | 15篇 |
农学 | 5篇 |
60篇 | |
综合类 | 101篇 |
农作物 | 56篇 |
水产渔业 | 17篇 |
畜牧兽医 | 351篇 |
园艺 | 19篇 |
植物保护 | 35篇 |
出版年
2019年 | 12篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 5篇 |
2015年 | 9篇 |
2014年 | 12篇 |
2013年 | 37篇 |
2012年 | 25篇 |
2011年 | 25篇 |
2010年 | 19篇 |
2009年 | 21篇 |
2008年 | 23篇 |
2007年 | 24篇 |
2006年 | 17篇 |
2005年 | 24篇 |
2004年 | 12篇 |
2003年 | 14篇 |
2002年 | 14篇 |
2001年 | 12篇 |
2000年 | 21篇 |
1999年 | 15篇 |
1998年 | 22篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 9篇 |
1993年 | 13篇 |
1992年 | 7篇 |
1991年 | 14篇 |
1990年 | 21篇 |
1989年 | 11篇 |
1988年 | 10篇 |
1987年 | 9篇 |
1985年 | 10篇 |
1984年 | 12篇 |
1983年 | 10篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 10篇 |
1979年 | 12篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1972年 | 9篇 |
1971年 | 4篇 |
1970年 | 6篇 |
1967年 | 7篇 |
1955年 | 4篇 |
排序方式: 共有659条查询结果,搜索用时 0 毫秒
41.
S. R. Aston I. Thornton J. S. Webb J. B. Purves B. L. Milford 《Water, air, and soil pollution》1974,3(3):321-325
The trace element composition of stream sediments from catchments contaminated by past and present mining activities has been used to indicate the trace element status of associated waters. The paper discusses the possibility of using geochemical reconnaissance maps based on the analysis of stream sediments as an ancillary aid to water quality evaluation. 相似文献
42.
43.
44.
45.
The feasibility of autologous intrarenal mesenchymal stem cell (MSC) therapy in cats with chronic kidney disease (CKD) was investigated. Six cats (two healthy, four with CKD) received a single unilateral intrarenal injection of autologous bone marrow-derived or adipose tissue-derived MSC (bmMSC or aMSC) via ultrasound guidance. Minimum database and glomerular filtration rate (GFR) via nuclear scintigraphy were determined pre-injection, at 7 days and at 30 days post-injection. Intrarenal injection did not induce immediate or long-term adverse effects. Two cats with CKD that received aMSC experienced modest improvement in GFR and a mild decrease in serum creatinine concentration. Despite the possible benefits of intrarenal MSC injections for CKD cats, the number of sedations and interventions required to implement this approach would likely preclude widespread clinical application. We concluded that MSC could be transferred safely by ultrasound-guided intrarenal injection in cats, but that alternative sources and routes of MSC therapy should be investigated. 相似文献
46.
47.
Johannes Vernooij Florine de Munck Evelien van Nieuwenhuizen Edward Webb Herman Jonker Peter Vos Dietmar Holm 《Reproduction in domestic animals》2020,55(11):1592-1598
Pelvis size plays an important role to prevent dystocia in cattle caused by the foeto-maternal disproportion in commonly primiparous females. The reproducibility and repeatability are two important aspects for the reliability of the measurements to use in the selection of cattle for culling. Pelvic measures were taken with a Rice pelvimeter from 224 young cattle (180 females and 44 males) of four beef breeds in South Africa. One experienced and two inexperienced observers each measured pelvic height and width twice. The proportion measurements with a maximum difference of 0.5 cm within animal compared with the first measurement by the experienced observer are around 80% and by the inexperienced observers around 50% for pelvic height and around 60% for pelvic width. Breed and sex do not affect the reliability of pelvimetry by an experienced observer. Under- and overestimation of pelvis size were observed in inexperienced observers, which seems to be unrelated to breed and sex. 相似文献
48.
Experimental infection of normal and immunosuppressed pigs with Pseudomonas pseudomallei 总被引:1,自引:0,他引:1
AD THOMAS JC FORBES-FAULKNER TL D''ARCY JH NORTON D HOFFMANN 《Australian veterinary journal》1990,67(2):43-46
A single dose of 5 x 10(8) bacilli of Pseudomonas pseudomallei by intratracheal injection resulted in acute (21 cases) or chronic (19 cases) melioidosis in 40 of 48 pigs. Fifteen (10 acute and 5 chronic) had been immunosuppressed by cyclophosphamide before inoculation. The major clinical signs were initial fever, marked neutrophilia and, in the acute cases, respiratory distress. There were no signs of the nasal and ocular discharge, paresis or diarrhoea seen in acute cases in south-east Asia. The cyclophosphamide treatment caused a significant decrease in the neutrophil count by 7 d after inoculation in all 15 immunosuppressed pigs, and all were culture positive at necropsy. Eight of the 33 non-treated pigs were culture negative at necropsy. Pigs overcoming the initial phase of infection had more abscess-like nodules that were bacteriologically sterile at necropsy than the pigs with acute cases of melioidosis. P. pseudomallei was isolated predominantly from the spleen, lungs and the injection site. Although only one strain was used in this study, it is likely that Australian strains of P. pseudomallei are not as virulent as the south-east Asian isolates. 相似文献
49.
Dr Stephen Collier Dr Bob Bradley Faith Rosson Will Gartrell Dr Bob Bradley Alistair Webb Dr Graham Thompson Dr Elaine Cebuliak 《Australian veterinary journal》2001,79(5):320-322
Editor's note: The AVJ welcomes letters from members in all areas of the profession on matters of importance to you. Please keep them brief ‐ to meet our space constraints. Letters will be subject to minimal editing procedures. Subject to letters complying with the AVJ's legal responsibilities, they will not be censored. Nor will individuals or groups waging'‘campaigns’ be permitted to abuse these pages. If submitting a letter intended for publication, kindly identify it as such. Letters to the Editor can be sent by mail, fax or e‐mail at the contact points listed at the start of the News Section. Writers may use a pseudonym to protect their identities ‐ but must supply the Editor with verifiable names and points of contact. 相似文献
50.
A control and a 10% fat-supplemented diet were fed to exercising horses maintained in two different body conditions, during both temperate and hot weather, to determine the efficacy of fat as dietary aid to reduced energy requirements for thermal regulation in exercising horses. Horses were worked 7.2 km daily, 5 d/w, and in each season were fed sufficient energy to maintain constant body weight and body fat content at each assigned level of body condition. In both seasons and in both body conditions, digestible energy intake was lower (P<.01) when the horses were fed the fat-supplemented diet than when fed the control diet. Digestible energy intake was partitioned into requirements for work and maintenance. Since work levels were similar, digestible energy requirements for work were similar when horses were fed both experimental diets. However, the digestible energy requirements for maintenance were significantly lower (P<.01) when the horses were fed the fat-supplemented diet. Thus, it appears that feeding fat to exercising horses reduces the thermal load and resulting digestible energy requirements for maintenance in both temperate and hot weather. 相似文献