全文获取类型
收费全文 | 1149篇 |
免费 | 82篇 |
国内免费 | 95篇 |
专业分类
林业 | 122篇 |
农学 | 54篇 |
基础科学 | 83篇 |
81篇 | |
综合类 | 486篇 |
农作物 | 132篇 |
水产渔业 | 42篇 |
畜牧兽医 | 159篇 |
园艺 | 127篇 |
植物保护 | 40篇 |
出版年
2024年 | 14篇 |
2023年 | 29篇 |
2022年 | 49篇 |
2021年 | 66篇 |
2020年 | 54篇 |
2019年 | 50篇 |
2018年 | 27篇 |
2017年 | 53篇 |
2016年 | 38篇 |
2015年 | 47篇 |
2014年 | 55篇 |
2013年 | 65篇 |
2012年 | 84篇 |
2011年 | 69篇 |
2010年 | 90篇 |
2009年 | 52篇 |
2008年 | 65篇 |
2007年 | 64篇 |
2006年 | 60篇 |
2005年 | 72篇 |
2004年 | 48篇 |
2003年 | 26篇 |
2002年 | 26篇 |
2001年 | 33篇 |
2000年 | 35篇 |
1999年 | 14篇 |
1998年 | 3篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 9篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1981年 | 1篇 |
1962年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有1326条查询结果,搜索用时 15 毫秒
1.
福建省森林公园建设现状、存在问题及解决对策 总被引:2,自引:0,他引:2
阐叙福建省森林公园建设发展现状、并着重对森林公园建设发展、资金投入、景观开发、森林景观、经营管理、管理体制等存问题提出相应的解决对策。 相似文献
2.
3.
介绍了江西省泰和县进行水稻机插秧技术与手工插秧对比试验。对不同农艺的经济效益和不同育秧方式的适应性进行了分析,并指出了目前技术措施存在的不足之处。 相似文献
4.
5.
AIM:To investigate therapeutic effects of recombinant human growth hormone(rhGH) on rat sepsis and its possible mechanisms.METHODS:Mean arterial pressure (MAP), levels of plasma TNFα, IL-1β and endotoxin, leukocyte count and survival rate within 1 week were determined after E. coli injection among control group, sepsis group and sepsis+rhGH group.RESULTS:(1)rhGH diminished the decrease of MAP, reduced plasma endotoxin and TNFα levels and increased neutrophil ratio in total leukocytes in sepsis rat. rhGH increased survival rate within 1 week on sepsis rat. (2)No changes were found in IL-1β level among the three groups.CONCLUSION:rhGH showed desirable beneficial effects on rat sepsis, which may attribute to: improving circulatory function;maintaining intestinal mucosa barrier, attenuating bacteria/endotoxin translocation and inhibiting the production and release of TNFα. 相似文献
6.
AIM: To examine the expression of human endostatin in E.coli, produce its fusion protein antibody and observe its biological activity. METHODS: Endostatin gene was amplified by polymerase chain reaction,recombined with plasmid vector pGEX-2T and induced expression with IPTG.The protein activity was tested by endothelial cell proliferation inhibitory assay.Inclusion body crudely purified was used to generate polyclonal antibody to detect its expression at mouse's liver and kidney etc. RESULTS: The protein expressed was 20kD after digestion by thrombin,it appeared the anti-angiogenesis activity and Western blotting indicated the expression of endostatin in liver and kidney of mouse. CONCLUSION: The successful expression of human endostatin and the preparation of polycolonal antibody indicated its potential application in anti-angiogenesis therapy and diagnosis tumors. 相似文献
7.
8.
ZHANG Zhan-jun YING Kang WANG Zhong ZHANG Xiao-yan LIU Jian-xun HUANG Yan XU Li WEI Cui-e WANG Yong-yan 《园艺学报》2004,20(8):1427-1433
AIM: To investigate the genes differential expression in cortex during rat focal cerebral ischemia.METHODS: cDNA microarray chips containing numerous cDNAs were used to investigate the gene expression pattern between samples of focal cerebral ischemia and sham-control operation rats. RESULTS: Two hundred and eleven genes differentially expressed were screened out, among these genes, up-and down-regulated genes were 199 and 12, respectively. CONCLUSIONS: The analysis of gene expression pattern of focal cerebral ischemia based on cDNA microarray can realize high-throughput screening of the genes associated with the focal cerebral ischemia. The differential expression of genes may be related to the pathogenesis of focal cerebral ischemic diseases. 相似文献
9.
AIM: To study the effect of propolis on the expression of CD54 and activation of NF-κB p65 in lung tissue of acute lung injury (ALI) rats. METHODS: 40 male Wistar rats were divided into 5 groups: normal control, model control, dectancyl group, water soluble derivative of propolis (WSP) group and ethanol extracted propolis (EEP) group. ALI animal model was performed by oleic acid and LPS twice attack. The pathologic slice was observed with light microscope and the NF-κB p65 activity and CD54 expression were tested by immunohistochemistry (SABC and SP). RESULTS: Both EEP and WSP antagonized the lung edema, decreased the inflammation and inhibited the expression of CD54 and activation of NF-κB p65. CONCLUSION: The increase in the expression of CD54 and the activation of NF-κB p65 in the lung tissues of ALI were involved in the formation of ALI. Propolis ameliorated the lung damage, which maybe related to the inhibition of CD54 expression and NF-κB p65 activation. 相似文献
10.
不同温度下圆叶决明降解过程红壤可溶性氮及氮水解酶动态变化研究 总被引:1,自引:0,他引:1
为了探明圆叶决明(Chamaecrista rotundifolia)降解过程果园红壤供氮水平的变化规律,本研究采用模拟培养试验,研究15℃和25℃培养果园红壤硝态氮、铵态氮、可溶性总氮、可溶性有机氮含量的变化及脲酶、蛋白酶、天冬酰胺酶活性的变化。结果表明,圆叶决明降解过程果园红壤4种可溶性氮含量均显著提高,且在培养140 d达到最大值,25℃培养的效果更佳。其中,可溶性总氮、可溶性有机氮和硝态氮含量随时间的动态变化可用三次曲线方程来拟合。圆叶决明降解过程还能显著提高脲酶、蛋白酶和天冬酰胺酶的活性,其中蛋白酶活性和脲酶活性的变化可用指数方程和三次曲线方程来拟合。本研究认为圆叶决明降解过程可提高果园红壤可溶性氮含量,因此可通过翻压圆叶决明提高土壤的供氮水平。 相似文献