全文获取类型
收费全文 | 16122篇 |
免费 | 952篇 |
国内免费 | 1972篇 |
专业分类
林业 | 1697篇 |
农学 | 2281篇 |
基础科学 | 1383篇 |
2623篇 | |
综合类 | 5236篇 |
农作物 | 1044篇 |
水产渔业 | 759篇 |
畜牧兽医 | 2384篇 |
园艺 | 602篇 |
植物保护 | 1037篇 |
出版年
2024年 | 58篇 |
2023年 | 187篇 |
2022年 | 506篇 |
2021年 | 704篇 |
2020年 | 680篇 |
2019年 | 673篇 |
2018年 | 475篇 |
2017年 | 672篇 |
2016年 | 630篇 |
2015年 | 788篇 |
2014年 | 759篇 |
2013年 | 871篇 |
2012年 | 1093篇 |
2011年 | 1171篇 |
2010年 | 1113篇 |
2009年 | 996篇 |
2008年 | 964篇 |
2007年 | 906篇 |
2006年 | 847篇 |
2005年 | 712篇 |
2004年 | 394篇 |
2003年 | 368篇 |
2002年 | 413篇 |
2001年 | 384篇 |
2000年 | 367篇 |
1999年 | 358篇 |
1998年 | 283篇 |
1997年 | 251篇 |
1996年 | 212篇 |
1995年 | 213篇 |
1994年 | 190篇 |
1993年 | 165篇 |
1992年 | 153篇 |
1991年 | 114篇 |
1990年 | 104篇 |
1989年 | 98篇 |
1988年 | 52篇 |
1987年 | 41篇 |
1986年 | 29篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 12篇 |
1980年 | 5篇 |
1956年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
对3种昆虫生长调节剂和2种生物农药对韭蛆田间防效进行了初步评价。春季试验结果表明,10%高渗烟碱水剂1000倍液防效最好,达70.0%以上;70%灭蝇胺可湿性粉剂3000倍液和0.3%印楝素乳油1000倍液次之;而5%卡死克乳油800倍液和5%抑太保乳油1000倍液的防效较差。将春季试验药效较好的3种农药用于秋季田间试验,结果表明,10%高渗烟碱水剂1000倍液和70%灭蝇胺可湿性粉剂3000倍液防效较好,特别是10%高渗烟碱水剂的防效达到79.8%,几乎与40%辛硫磷乳油1000倍液相当。0.3%印楝素乳油1000倍液的防效较差,仅为69.2%。 相似文献
994.
995.
996.
AIM: To investigate the cell cycle arrest induced by hypoxia, hypoxia inducible factor-1 and their possible mechanism in human ovarian cancer cell line SW626. METHODS: CoCl2, a chemical inducer of hypoxia and hypoxic cell culture chamber were used to induce chemical and physical hypoxia in human ovarian cancer cell line SW626. The method of ‘decoy’ was used to block the function of HIF-1α because it acts as the core sequence of the target gene as a competitor combined to the HIF-1α. The cells were divided into group A1 (normal oxygen), A2 (normal oxygen plus HIF-1α decoy), B1 (CoCl2), B2 (CoCl2 plus HIF-1α decoy), C1 (hypoxia) and C2 (hypoxia plus HIF-1α). The expression of the HIF-1α protein, mRNA and cell cycle analysis were detected by Western blotting, RT-PCR and flow cytometry (FCM). RESULTS: The expression level of HIF-1α protein in group B1 (3.75±1.31) and group C1 (3.48±1.01) was significantly higher than that in group A1 (0.97±0.31) (P<0.05). The expression levels of HIF-1α mRNA in group A1 (0.65±0.32) and group B1 (0.64±0.34) were significantly lower than that in group C1 (1.28±0.62) (P<0.05). Decoy had no effect in the expression of HIF-1α protein and mRNA level (P>0.05). FCM showed that the G0/G1 phase was markedly increased in group B1 (81.78±24.33) and group C1 (77.62±22.76) and was significantly higher than that in group A1 (49.49±18.54) (P<0.05), group B2 (61.54±20.84) was lower than that in group B1 with statistical significance (P<0.05) and group C2 (56.03±21.42) was lower than that in group C1 with statistical significance (P<0.05) , but the difference between group A1 and group A2 (51.77±16.45) had no statistical significance (P>0.05). CONCLUSION: Both CoCl2 and physical hypoxia could distinctly induce cell cycle arrest in G0/G1 phase and the expression of HIF-1α in human ovarian cancer cell line SW626. HIF-1α plays an important role in cell cycle arrest induced by hypoxia in human ovarian cancer cell line SW626. 相似文献
997.
998.
Dry fungal biomass ofPenicillium chrysogenum (dry mycelium), a waste product of the pharmaceutical industry, was extracted with water and applied to the roots of melon
plants before or after inoculation withFusarium oxysporum f.sp.melonis (Font). Seedlings (4–6 days after emergence) treated with either acidic dry mycelium extract (DME) or neutralized dry mycelium extract
(NDME) were protected against challenge infection withFom. A single drench with 2–5% DME applied 12–72 h before inoculation provided significant control of the disease compared with
water-drenched, challenged seedlings. No protection was seen in plants treated 0–6 h before inoculation or 0–48 h after inoculation.
Neither DME nor NDME (0.5–5%) had any effect on fungal growthin vitro, which implied that disease controlin vivo was mediated by induced resistance. The resistance induced by DME protected melon plants not only against race 1,2, but also
against the three other races of the pathogen, indicating a race-non-specific resistance againstFom. Both DME and NDME significantly increased peroxidase activity and free L-proline content in seedlings 12 h and 48 h after
soil drench, respectively. Resistance to Fusarium wilt was significantly associated with elevated levels of peroxidase activity
but not with free L-proline content. Thus, peroxidase might be involved in the defense mechanisms activated by DME or NDME.
http://www.phytoparasitica.org posting Aug. 31, 2001. 相似文献
999.
1000.