全文获取类型
| 收费全文 | 1866篇 |
| 免费 | 121篇 |
| 国内免费 | 23篇 |
专业分类
| 林业 | 64篇 |
| 农学 | 35篇 |
| 基础科学 | 31篇 |
| 175篇 | |
| 综合类 | 545篇 |
| 农作物 | 97篇 |
| 水产渔业 | 50篇 |
| 畜牧兽医 | 859篇 |
| 园艺 | 39篇 |
| 植物保护 | 115篇 |
出版年
| 2023年 | 13篇 |
| 2022年 | 13篇 |
| 2021年 | 22篇 |
| 2020年 | 34篇 |
| 2019年 | 26篇 |
| 2018年 | 31篇 |
| 2017年 | 35篇 |
| 2016年 | 39篇 |
| 2015年 | 28篇 |
| 2014年 | 41篇 |
| 2013年 | 116篇 |
| 2012年 | 81篇 |
| 2011年 | 97篇 |
| 2010年 | 65篇 |
| 2009年 | 44篇 |
| 2008年 | 66篇 |
| 2007年 | 79篇 |
| 2006年 | 76篇 |
| 2005年 | 67篇 |
| 2004年 | 66篇 |
| 2003年 | 51篇 |
| 2002年 | 51篇 |
| 2001年 | 30篇 |
| 2000年 | 37篇 |
| 1999年 | 41篇 |
| 1998年 | 21篇 |
| 1997年 | 13篇 |
| 1995年 | 20篇 |
| 1993年 | 13篇 |
| 1992年 | 25篇 |
| 1991年 | 33篇 |
| 1990年 | 28篇 |
| 1989年 | 27篇 |
| 1988年 | 29篇 |
| 1987年 | 24篇 |
| 1986年 | 17篇 |
| 1985年 | 29篇 |
| 1984年 | 30篇 |
| 1982年 | 16篇 |
| 1979年 | 14篇 |
| 1978年 | 22篇 |
| 1977年 | 17篇 |
| 1975年 | 19篇 |
| 1974年 | 19篇 |
| 1973年 | 12篇 |
| 1972年 | 13篇 |
| 1971年 | 15篇 |
| 1970年 | 14篇 |
| 1968年 | 15篇 |
| 1937年 | 11篇 |
排序方式： 共有2010条查询结果，搜索用时 992 毫秒
101.
102.
D M Haines J C Kendall B W Remenda M M Breker-Klassen E G Clark 《Journal of veterinary diagnostic investigation》1992,4(4):393-399
Accurate identification of bovine parainfluenza type 3 virus in bovine respiratory disease requires dependable, sensitive, and specific techniques for detection in affected animals. Immunohistochemical testing can be a rapid and reliable means of demonstration of virus in tissues from suspect cases; however, this procedure is dependent upon the quality of the antisera directed against the viral antigens. The production of rabbit polyclonal and murine monoclonal antibodies directed against bovine parainfluenza type 3 virus and techniques for their use in fresh-frozen and formalin-fixed paraffin-embedded tissues in immunofluorescence and immunoperoxidase-based immunohistochemical tests are described. 相似文献
103.
104.
采用造林技术于冻结滞水理论技术相结合的方法,研究树木根系发育分布与冻结滞水的相关性,为防治荒漠,提高造林成活率提供理论技术依据,研究结果表明,苗木和高秆造林树木根系主要分布在地表以下20 cm~75 cm深度内,即冻结滞水富水带内,含水量达40%~50%,春季冻融水满足苗木生根成活的要求.80 cm~160 cm深度分贫水带,含水量〉5%,高杆造林树木根系极少.到160 cm~200 cm含水量增加,发育,第二层根系。冻结滞水资源是提高苗木成活率,生存繁的重要水资源。 相似文献
105.
106.
The effects of intravenous infusion of endotoxin for 30 minutes at a cumulative dosage of 0.03 micrograms/kg on average carotid arterial pressure, and on average arterial pressure, capillary pressure, venous pressure, total vascular resistance, precapillary resistance, postcapillary resistance, and capillary filtration coefficient in the jejunum were compared to the effects of intravenous infusion of 0.9% sodium chloride solution in 6 anesthetized horses. Endotoxin significantly reduced intestinal venous blood flow by inducing vasoconstriction. Increased vascular resistance resulted from increased precapillary resistance. The capillary filtration coefficient was unchanged by endotoxin. These results suggest that intestinal vasoconstriction occurs during the compensatory stages of endotoxemia. 相似文献
107.
Objective: To investigate the relative efficacy and safety of the anthelmintic naphthalophos in sheep, either given alone or in combination with benzimidazole (fenbendazole and albendazole) or levamisole anthelmintics.
Design: A parasitological study using faecal egg count reduction tests, a validating slaughter trial and field safety trials.
Procedure: Faecal egg count reduction tests were carried out on 13 farms. Naphthalophos and combinations of naphthalophos with levamisole and fenbendazole were included in the drench tests. On one property a controlled efficacy study was carried out to validate faecal egg count reduction test findings. In this trial, sheep were slaughtered 10 days after treatment and the remaining parasites recovered from the gastro-intestinal tract. Safety trials were carried out on eight farms where approximately 50 000 sheep were treated with naphthalophos and albendazole that were tank mixed in the backpack.
Results: The efficacy of naphthalophos alone in faecal egg count reduction tests ranged from 59 to 98% with one test showing 95% reduction. The efficacy of naphthalophos and levamisole ranged from 74 to 100%, with 5 farms showing 95% reduction. The efficacy of naphthalophos and fenbendazole ranged between 88 and 100% with 95% reduction achieved on 10 farms. The controlled efficacy study showed a good correlation between the faecal egg count reduction tests and numbers of parasites recovered, except for Nematodirus where the faecal egg count reduction tests overestimated efficacy. The mortality rate in the safety trials was 0.05%, with most fatalities occurring on one farm.
Conclusion: The combination of naphthalophos and fenbendazole was more effective than a combination of naphthalophos and levamisole, and will provide a sufficiently safe drench rotation option. 相似文献
Design: A parasitological study using faecal egg count reduction tests, a validating slaughter trial and field safety trials.
Procedure: Faecal egg count reduction tests were carried out on 13 farms. Naphthalophos and combinations of naphthalophos with levamisole and fenbendazole were included in the drench tests. On one property a controlled efficacy study was carried out to validate faecal egg count reduction test findings. In this trial, sheep were slaughtered 10 days after treatment and the remaining parasites recovered from the gastro-intestinal tract. Safety trials were carried out on eight farms where approximately 50 000 sheep were treated with naphthalophos and albendazole that were tank mixed in the backpack.
Results: The efficacy of naphthalophos alone in faecal egg count reduction tests ranged from 59 to 98% with one test showing 95% reduction. The efficacy of naphthalophos and levamisole ranged from 74 to 100%, with 5 farms showing 95% reduction. The efficacy of naphthalophos and fenbendazole ranged between 88 and 100% with 95% reduction achieved on 10 farms. The controlled efficacy study showed a good correlation between the faecal egg count reduction tests and numbers of parasites recovered, except for Nematodirus where the faecal egg count reduction tests overestimated efficacy. The mortality rate in the safety trials was 0.05%, with most fatalities occurring on one farm.
Conclusion: The combination of naphthalophos and fenbendazole was more effective than a combination of naphthalophos and levamisole, and will provide a sufficiently safe drench rotation option. 相似文献
108.
109.
110.
Stressors such as transportation, weaning and co-mingling increase susceptibility to bacterial pneumonia in cattle and are associated with elevated levels of endogenous glucocorticoids. To determine the effect of glucocorticoids on the proteins expressed in the fluid lining the respiratory tract, bronchoalveolar lavage (BAL) was performed on cattle treated with dexamethasone or saline and proteins were resolved by two-dimensional electrophoresis (2-DE). Significant changes in expression were observed for 9 of the 363 detected spots, and the identities of these proteins were determined by mass spectrometry. Consistent with the initiation of an acute phase response, the expression of alpha-1-acid glycoprotein (orosomucoid) and alpha-1-antitrypsin was increased and alpha-2-HS-glycoprotein (fetuin) was decreased in the BAL fluid of dexamethasone-treated cattle. In addition, dexamethasone induced the expression of two hydrophobic ligand-binding proteins, adipocyte-fatty acid binding protein and odorant binding protein (OBP), as well as the proteins alpha-enolase, cofilin-1 and immunoglobulin J chain. OBP mRNA expression in bronchial biopsies was quantified by real-time RT-PCR and the 6-fold higher levels of expression observed in dexamethasone- versus saline-treated animals correlated with the changes observed in OBP protein level. These findings demonstrate glucocorticoid-dependent changes in the protein composition of the epithelial lining fluid of the respiratory tract, identifying proteins potentially integral to respiratory disease susceptibility. 相似文献