全文获取类型
收费全文 | 3176篇 |
免费 | 187篇 |
国内免费 | 325篇 |
专业分类
林业 | 248篇 |
农学 | 185篇 |
基础科学 | 130篇 |
383篇 | |
综合类 | 1492篇 |
农作物 | 201篇 |
水产渔业 | 164篇 |
畜牧兽医 | 472篇 |
园艺 | 241篇 |
植物保护 | 172篇 |
出版年
2024年 | 32篇 |
2023年 | 77篇 |
2022年 | 180篇 |
2021年 | 170篇 |
2020年 | 148篇 |
2019年 | 126篇 |
2018年 | 112篇 |
2017年 | 178篇 |
2016年 | 117篇 |
2015年 | 171篇 |
2014年 | 171篇 |
2013年 | 208篇 |
2012年 | 274篇 |
2011年 | 260篇 |
2010年 | 253篇 |
2009年 | 212篇 |
2008年 | 221篇 |
2007年 | 203篇 |
2006年 | 146篇 |
2005年 | 102篇 |
2004年 | 74篇 |
2003年 | 43篇 |
2002年 | 62篇 |
2001年 | 60篇 |
2000年 | 53篇 |
1999年 | 9篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1986年 | 3篇 |
1981年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有3688条查询结果,搜索用时 15 毫秒
61.
62.
CHEN Tian-tian CHENG Fu-liang ZHANG Jian-mei NIE Zhao-jing FANG Dong FAN Mei-na LI Fu-hui CHENG He-gang 《中国畜牧兽医》2015,42(9):2474-2480
The inhibitory effects of rhubarb on cell lesion, which was caused by porcine epidemic diarrhea virus (PEDV), and its mechanism had been studied in this research.The maximum safe concentration of rhubarb solution applied to Vero cells was determined through morphological observation, and then the PEDV infected Vero cell model in vitro was established, by which the inhibitory effect of rhubarb on virus was studied.The experimental method had also been established based on this cell model.The result showed that the maximum safe concentration was 3.28 mg/mL.Both morphological observation and MTT assay were indicated that rhubarb could not only block the attachment of the virus to Vero cell and inhibit the synthesis and reproduction of the virus, but also could directly inactivate the virus.This research showed that rhubarb had an inhibitory effect on PEDV, and provided a theoretical basis for the prevention and treatment of clinical porcine epidemic diarrhea. 相似文献
63.
WANG Meng-zhu LIU Yan-feng WANG Wen-qi NIE Cun-xi TANG Shu-zhen ZHANG Wen-ju 《中国畜牧兽医》2015,42(9):2345-2351
This experiment was conducted to evaluate the effect of alfalfa flavonoids (Medicago sativa) on growth performance and serum indexes of sheep.This experiment was performed with hybrid F1 sheep of Suffolk sheep×Small-tailed Han sheep.Twenty-eight sheep with the body weight of (27.02±3.03) kg were randomly divided into 4 groups with 7 replicates in each group and 1 sheep per replicate.Sheep in different groups were fed diets with 0 (group Ⅰ), 0.1% (group Ⅱ), 0.2%(group Ⅲ) and 0.4% (group Ⅳ) alfalfa flavonoids, respectively.The experiment was cosisted of 7-day-preliminary trial and 41-day-formal trial.The results showed as follows:① Dietary supplementation of alfalfa flavonoids had no significant effects on growth performance of sheep(P>0.05).② Dietary supplementation of alfalfa flavonoids had significant effects on the contents of GLB, ASP, BUN, HDL and P in serum (P<0.05).Serum GLB content at the 1st day in group Ⅲ was significantly lower than that in groupsⅠand Ⅱ(P<0.05), serum ASP contents at the 1st and 21th days in group Ⅳ were significantly lower than those in group Ⅰ(P<0.05), serum BUN content at the 1st day in group Ⅳ was significantly lower than that in group Ⅰ(P<0.05), serum HDL content at the 21th day in group Ⅱ was significantly lower than that in groups Ⅰ and Ⅲ (P<0.05), serum P content in group Ⅳ at the 21th day was significantly lower than that in groups Ⅱ and Ⅲ (P<0.05).In conclusion, dietary supplementation of alfalfa flavonoids might modulate lipid metabolism, improve nitrogen utilization, maintain energy metabolic and balance Ca and P contents, and have the potential function for promoting growth and no adverse effect on liver.The results suggested that the appropriate supplemental level of alfalfa flavonoids for sheep was 0.2%. 相似文献
64.
65.
66.
Characterization of Genomic Integration and Transgene Organization in Six Transgenic Rapeseed Events
To characterize the DNA rearrangement of both the T-DNA region and the genomic insertion site during T-DNA insertion, the Genomewalker strategy was used to isolate the junctions between the inserted DNA and the plant genomic DNA in six rapeseed events as well as the genomic DNA at the sites before integration. During transformation in each of the six events, portions of both the right border(RB) and left border(LB) regions of the T-DNA were deleted, ranging from a 7 nucleotide deletion of the LB repeats in event RF1 to a 207 bp deletion of the LB region in event RF2. For the six events, T-DNA integration resulted in a deletion at the target site spanning less than 100 bp. Sequence analysis indicated that the T-DNA was integrated into the coding region of various native rapeseed genes in events RF1 and RF2. Duplications of the genomic DNA target site were observed in events RF2, RF3 and Topas 19/2. And multimerization of transgenes was found in event Topas 19/2, in which, the T-DNA was integrated as a head-to-head(RB-to-RB) concatemer into the recipient genome. In event MS1, chromosomal translocation or a large target-site deletion may have occurred during T-DNA integration, which was identified due to a failure to amplify the presumptive insertion site based on the flanking rapeseed DNA sequences. Our results provide comprehensive data concerning transgene organization and the genomic context of the T-DNA in six rapeseed events, which can aid in the developing of insert fingerprinting and the monitoring of long-term genetic stability and potential unintended effects of transgenic events. 相似文献
67.
【目的】研究补喂支链氨基酸(BCAA)、肌酸(Cr)对伊犁马血浆抗氧化指标、激素水平、肌酸、葡萄糖浓度以及乳酸、尿酸和肌酐含量的影响,为支链氨基酸、肌酸作为伊犁马有效的营养添加剂提供参考数据。【方法】选取年龄3~5岁(平均4岁),体重390~514 kg(平均457±50 kg),经过良好训练的伊犁马公马12匹进行试验。分为3组,每组4匹,分别为对照组、试验Ⅰ组和试验Ⅱ组。对照组补喂不添加任何添加物的补喂料,试验Ⅰ组补喂添加BCAA的补喂料,试验Ⅱ组补喂添加Cr的补喂料。分别在补饲的0、1、14、21和31 d补喂后4 h颈静脉采集血液。采用试剂盒法测定相关指标。【结果】补喂Cr能够明显提高T-AOC能力,Cr补喂组与对照组差异显著(P<0.05),特别是在14和31d比对照组提高了21.79%和25.68%;补喂BCAA降低试验期间MDA的含量;对于血浆中的胰岛素、胰高血糖素和皮质醇等3种激素水平,肌酸、葡萄糖、乳酸、尿酸和肌酐的浓度与对照组相比差异不显著(P>0.05)。【结论】补喂BCAA可以降低脂质过氧化产物MDA的浓度;补喂Cr可以提高SOD的活力和提高伊犁马血浆的T-AOC能力;补喂BCAA、Cr对伊犁马血浆中的胰岛素、胰高血糖素和皮质醇等3种激素的水平均无显著影响;对浆中肌酸、葡萄糖的浓度均无显著影响;对血浆中乳酸、尿酸和肌酐的含量均无显著影响。 相似文献
68.
69.
70.