全文获取类型
收费全文 | 5936篇 |
免费 | 265篇 |
国内免费 | 454篇 |
专业分类
林业 | 301篇 |
农学 | 245篇 |
基础科学 | 231篇 |
440篇 | |
综合类 | 2893篇 |
农作物 | 374篇 |
水产渔业 | 174篇 |
畜牧兽医 | 1148篇 |
园艺 | 601篇 |
植物保护 | 248篇 |
出版年
2024年 | 31篇 |
2023年 | 85篇 |
2022年 | 184篇 |
2021年 | 190篇 |
2020年 | 170篇 |
2019年 | 183篇 |
2018年 | 138篇 |
2017年 | 229篇 |
2016年 | 137篇 |
2015年 | 283篇 |
2014年 | 292篇 |
2013年 | 403篇 |
2012年 | 563篇 |
2011年 | 621篇 |
2010年 | 557篇 |
2009年 | 526篇 |
2008年 | 481篇 |
2007年 | 457篇 |
2006年 | 362篇 |
2005年 | 255篇 |
2004年 | 179篇 |
2003年 | 79篇 |
2002年 | 62篇 |
2001年 | 68篇 |
2000年 | 84篇 |
1999年 | 29篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
排序方式: 共有6655条查询结果,搜索用时 15 毫秒
1.
2.
党的十六届五中全会通过的《中共中央关于制定国民经济和社会发展第十一个五年规划的建议》站在历史的新高度,从战略全局出发,描绘了我国新世纪第二个五年经济社会发展的宏伟蓝图,是动员全党和全国各族人民全面建设小康社会、加快推进社会主义现代化的纲领性文件。 相似文献
4.
5.
JIANG An-li KANG Lu-dong ZHAO Chun-hua BI Wen-xiang HU Xiao-yan KONG Feng XU Song-de 《园艺学报》2003,19(1):55-58
AIM: In order to evaluate the applicable value of LDL as a targeted vehicle for chemotherapeutic agents, we investigated and compared the inhibitory effects of LDL-ACM complex and free ACM on nude mice's subcutaneous implanted tumors derived from gastric cancer cell lines, SGC-7901 and NKM-45. METHODS: LDL-ACM complex was prepared and the tumor model of nude mice was established by subcutaneous implantation of SGC-7901 and NKM-45. Then, the groups of nude mice developed subcutaneous implanted tumors were received either LDL-ACM complex or free ACM. Subsequently, the tumor size, weight and leukemia cell counts were measured and the rates of tumor-inhibition and the survival were compared among the groups. RESULTS: The inhibitory effects of LDL-ACM complex on the tumors, especially on SGC-7901 implanted tumors were much more obvious than that of free ACM. It was also indicated that the action of LDL-ACM complex was mediated by LDL receptor. CONCLUSION: These results showed that LDL-ACM complex had significant inhibitory effects on the implanted tumors and the effect might be mediated by LDL receptor. 相似文献
6.
鸭大肠杆菌的药物敏感性试验 总被引:3,自引:0,他引:3
采用纸片扩散法测定了14株鸭大肠杆菌对10种抗菌药物的敏感性,结果鸭大肠杆菌对头孢唑啉、头孢噻肟、丁胺卡那霉素最为敏感,敏感率均为100%;其次为庆大霉素,敏感率为78.6%;对其他抗菌药物均产生不同程度的耐药性,耐药性最为严重的是四环素、复方新诺明及多西环素,耐药率分别为92.9%、85.7%、78.6%,对阿莫西林、氯霉素、环丙沙星的耐药率分别为57.1%、50.0%、64.3%;78.6%的菌株对10种抗菌药物表现为多重耐药性.耐阿莫西林菌株经碘-淀粉测定法测定均为产β-内酰胺酶菌株,阿莫西林对它们的最小抑菌浓度范围为256~ 1 024 mg/L. 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.
10.
AIM: To investigate the role of adrenomedullin (AM) in diabetic nephropathy. METHODS: We observed the changes in the expression and secretion of AM, TGF-β1 in the cultured human mesangial cells under high glucose condition and the contents of the laminin and type IV collagen in the supernatants. The effect of intervention with AM was also observed. RESULTS: High glucose condition resulted in increase in the expression and secretion of AM、 TGF-β1、 laminin and type IV collagen. AM reversed the influence of high glucose on the cultured human mesangial cells. CONCLUSION: These results showed that high glucose condition is one of stimulating factors of AM and the renal protective action of AM may be associated with suppression of TGF-β1 and reducing excessive accumulat ion of laminin and type IV collagen. 相似文献