全文获取类型
收费全文 | 11063篇 |
免费 | 605篇 |
国内免费 | 1033篇 |
专业分类
林业 | 893篇 |
农学 | 505篇 |
基础科学 | 535篇 |
1191篇 | |
综合类 | 5354篇 |
农作物 | 861篇 |
水产渔业 | 591篇 |
畜牧兽医 | 1463篇 |
园艺 | 864篇 |
植物保护 | 444篇 |
出版年
2024年 | 83篇 |
2023年 | 230篇 |
2022年 | 498篇 |
2021年 | 467篇 |
2020年 | 438篇 |
2019年 | 455篇 |
2018年 | 281篇 |
2017年 | 508篇 |
2016年 | 347篇 |
2015年 | 461篇 |
2014年 | 526篇 |
2013年 | 672篇 |
2012年 | 934篇 |
2011年 | 969篇 |
2010年 | 953篇 |
2009年 | 836篇 |
2008年 | 851篇 |
2007年 | 799篇 |
2006年 | 615篇 |
2005年 | 550篇 |
2004年 | 343篇 |
2003年 | 192篇 |
2002年 | 222篇 |
2001年 | 168篇 |
2000年 | 184篇 |
1999年 | 50篇 |
1998年 | 9篇 |
1997年 | 10篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1987年 | 2篇 |
1981年 | 3篇 |
1962年 | 2篇 |
1956年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
91.
CAI Qing-qing LIN Tian-xin FANG Xin-lan YIN Xin-bao DONG Wen HUANG Li LIN Tong-yu 《园艺学报》2009,25(5):873-876
[ABSTRACT]AIM: To study the effect of 13-methyltetradecanoic acid (13-MTD), a saturated branched-chain fatty acid, on apoptotic induction in breast carcinoma cell line MCF-7 and its underlying mechanisms. METHODS: Breast carcinoma cell line MCF-7 and normal breast epithelial cells MaEC were treated with solvent or 13-MTD at concentration of 140 mg/L. Apoptosis was analyzed by flow cytometry. Phosphorylation of JNK, p38, FADD and Akt after treated with 13-MTD were detected by Western blotting. RESULTS: 13-MTD effectively induced apoptosis of breast carcinoma cell line MCF-7 and no influence to normal breast epithelial cells MaEC, which were confirmed by flow cytometry analysis, was observed. The results of Western blotting showed that obvious increase in p38 and JNK phosphorylation. No significant difference of FADD phosphorylation was observed. However, evidently decrease in Akt phosphorylation was found after treated with 13-MTD. CONCLUSION: 13-MTD was a new safe, effective chemotherapeutic drug. Its underlying mechanisms are through activating MAPK pathway and inhibiting Akt pathway to induce the cancer cells apoptosis. 相似文献
92.
AIM: To observe the damage induced in the primary cultured rat cortical neurons by oxygen/glucose deprivation and reintroduction, and to investigate the neuroprotective mechanism of salvianolic acid B (SalB). METHODS: Primary cultured rat cortical neurons were randomly divided into the control group, the model group and the SalB group. The cell model was established by oxygen/glucose deprivation for 3 h followed oxygen/glucose reintroduction for 24 h. The cortical neurons viability was determined by MTT assay. The leakage rate of lactate dehydrogenase (LDH) was measured by chromatometry. The mitochondrial membrane potentials (MMP) and the apoptosis rate were quantitatively analyzed by flow cytometry. The cytosolic free calcium was assessed using LSCM. The morphologic changes of neuronal nuclei were observed by Hoechst 33342 fluorescence staining. RESULTS: Compared to the model group, the cortical neurons viability, the survival rate and the fluorescence value of MMP in the SalB group were obviously increased (P<0.05,P<0.01). In addition, in the SalB group, the leakage rate of LDH, the fluorescence intensity of cytosolic free calcium and the apoptosis rate were significantly lower than those in the model group (P<0.01). CONCLUSION: The neuroprotective mechanism of SalB in the oxygen/glucose deprivation and reintroduction neurons would be due to the fact that SalB maintains the MMP and the calcium homeostasis. 相似文献
93.
94.
95.
96.
97.
98.
配电网地理图自动生成电气接线图是配电GIS图形转换的主要问题,要求生成的电气接线图与地理图信息完全一致,同时还要科学、美观.采用优化的节点提取拓扑分析方法分析配电地理图中网络拓扑结构.在常见处理方法的基础上提出一种快捷有效的算法,可根据配电网地理图中的地理信息自动生成电气接线图. 相似文献
99.
华南春大豆氮磷钾肥配施效应及用量研究 总被引:1,自引:0,他引:1
为探明华南春大豆生产的适宜施肥量,采用"3414"肥效试验设计,选用桂春豆106开展了氮磷钾肥配施效应和推荐施肥量研究。结果表明:氮、磷、钾肥料配施可明显提高华南春大豆产量,各肥料因素对大豆产量的增产效应依次为磷氮钾,氮、磷、钾三因素之间存在互作效应,效应大小依次为氮磷磷钾氮钾;经模型最优分析表明采用三元肥效函数模型做出施肥决策是合理可行的,经回归模型的拟合得出推荐施肥量,达到最高产量时氮(N)、磷(P_2O_5)和钾(K_2O)的施肥量分别为80.6,21.6和58.4 kg·hm~(-2),达到最佳经济产量时氮(N)、磷(P_2O_5)、钾(K_2O)的施肥量分别为75.5,21.3和54.1 kg·hm~(-2)。这些研究结果将为华南地区春大豆合理施肥提供指导,为下一步建立施肥指标体系提供依据。 相似文献
100.