全文获取类型
收费全文 | 24528篇 |
免费 | 1247篇 |
国内免费 | 2321篇 |
专业分类
林业 | 2643篇 |
农学 | 2694篇 |
基础科学 | 1425篇 |
3332篇 | |
综合类 | 8776篇 |
农作物 | 1782篇 |
水产渔业 | 1077篇 |
畜牧兽医 | 3759篇 |
园艺 | 1166篇 |
植物保护 | 1442篇 |
出版年
2024年 | 125篇 |
2023年 | 363篇 |
2022年 | 798篇 |
2021年 | 970篇 |
2020年 | 944篇 |
2019年 | 949篇 |
2018年 | 660篇 |
2017年 | 971篇 |
2016年 | 807篇 |
2015年 | 1063篇 |
2014年 | 1080篇 |
2013年 | 1326篇 |
2012年 | 1753篇 |
2011年 | 1769篇 |
2010年 | 1659篇 |
2009年 | 1529篇 |
2008年 | 1517篇 |
2007年 | 1400篇 |
2006年 | 1332篇 |
2005年 | 1100篇 |
2004年 | 564篇 |
2003年 | 481篇 |
2002年 | 475篇 |
2001年 | 402篇 |
2000年 | 465篇 |
1999年 | 488篇 |
1998年 | 394篇 |
1997年 | 343篇 |
1996年 | 316篇 |
1995年 | 310篇 |
1994年 | 271篇 |
1993年 | 275篇 |
1992年 | 228篇 |
1991年 | 176篇 |
1990年 | 176篇 |
1989年 | 152篇 |
1988年 | 124篇 |
1987年 | 92篇 |
1986年 | 51篇 |
1985年 | 31篇 |
1984年 | 31篇 |
1983年 | 22篇 |
1982年 | 19篇 |
1981年 | 15篇 |
1980年 | 14篇 |
1979年 | 10篇 |
1974年 | 7篇 |
1965年 | 8篇 |
1964年 | 10篇 |
1956年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
The study was aimed to explore the antioxident function of sulforaphane (SFN) on the leydig cells of cadmium (Cd) exposured mice.Cd and SFN were added to the cell culture medium of TM3 cell, half inhibitory concentration (IC50) of Cd and SFN safe dose range were determined.The tested model was set up,and the relative survival rate of TM3 cells, lactate dehydrogenase (LDH) activity and cell antioxidant levels were determined to study the antioxident function of SFN to cadmium exposured mice.The results showed that:①With the increase of Cd concentration,the relative survival rate of TM3 cells was decreased,and the IC50 of Cd was 51.4 μmol/L;Within a certain concentration range,SFN could increased the cells survive rate,but there was toxicity when the SFN concentration was more than the scope,and the greater the concentration,the greater the toxicity. At experimental condition,SFN safety concentration were 2.5,5 and 10 μmol/L.②Compared with the control group,the GSH content,the T-SOD and GSH-Px activities in Cd group were significantly or extremely significantly decreased (P < 0.05;P < 0.01),and the LDH activity,the MDA content were increased.Additionally,the LDH activity and MDA content of SFN groups were decreased,while others three indexes were increased. Compared with Cd group,the GSH content,the T-SOD and GSH-Px activities of Cd+SFN groups were significantly or extremely significantly increased (P < 0.05;P < 0.01),however,the LDH activity,MDA content were decreased. The result indicated that SFN had the antagonism effect on toxicity of Cd in TM3 cell. 相似文献
34.
35.
Xiaolong Wang Kehe Huang Jingbao Gao Xiangzhen Shen Chengyi Lin Gengdi Zhang 《Research in veterinary science》1997,62(3):275
The chemical composition and microstructure of seven uroliths and four urinary sediment samples associated with the feeding of high-level cottonseed meal diet to buffalo calves were examined by chemical qualitative analyses, scanning electron microscopy (
), X-ray diffraction, and X-ray energy dispersive spectrometry (
). Struvite was a major component of kidney stones and of some bladder stones. The kidney stone sample appeared cracked under low power under
, aggregated into tiny balls under high power, and as a bladelike structure under even higher power. The bladder stone samples appeared finely granular or granular with various forms of prismatic crystals. The urinary sediments were prismatic crystals, with granules. The newly found prismatic crystals, which were rich in potassium and similar to struvite in crystal structure, were identified as potassium magnesium phosphate (KMgPO4 · 6H2O) in some bladder stones and urinary sediments. However, crystals which contained Mg and P only, which had been used for struvite identification, were not found by
examination in urinary sediments from fresh urine samples of buffalo calves fed the high-level cottonseed meal diet. 相似文献
36.
37.
用食盐作为助溶剂采用细胞自溶法,对解脂假丝酵母33M candida lipolytica细胞壁进行破碎后提取神经酰胺,用SPE(固相萃取法)将神经酰胺与膜中其它脂类分离,分别应用TLC(薄层色谱)方法和HPLC-ELSD(高效液相色谱-蒸发光散射器)对其进行定性和定量分析,取得了良好效果。 相似文献
38.
39.
澳大利亚的动物健康维护体系 总被引:3,自引:0,他引:3
澳大利亚是畜牧业大国,也是世界上牲畜保健工作做得最好的国家之一,迄今尚未发生疯牛病等牲畜传染病.虽然地理条件有利于澳大利亚免受动物传染病的影响,但更重要的是,澳大利亚有一套完整的动物健康维护体系,这一体系是该国动物健康状况良好的根本保障,也是兽疫防控最根本的机制.…… 相似文献
40.
研究人参三醇组皂苷(PTS)对大鼠坐骨神经急性损伤蛋白表达的影响。建立大鼠坐骨神经挤压损伤模型,随机分为PTS组,模型对照组及空白对照组,每组各10只大鼠;各组均经腹腔注射给药,PTS组损伤后注射PTS;模型对照组,损伤后注射同剂量生理盐水;空白对照组,不损伤坐骨神经,注射同剂量生理盐水。坐骨神经损伤术后30d,免疫荧光化学染色检测PTS对损伤侧坐骨神经神经丝蛋白(NF-M)、微管相关蛋白-2(MAP-2)、生长相关蛋白(GAP-43)表达的影响,观察PTS对损伤侧神经的影响。大鼠损伤侧坐骨神经NF-M、MAP-2、GAP-43平均光密度表达(9.66±0.99、12.43±1.44、0.344±0.040)与模型对照组(8.21±1.25、11.90±1.14、0.278±0.042)比较有极显著性差异(P0.01)。PTS可促进坐骨神经损伤大鼠NF-M,MAP-2,GAP-43的表达。 相似文献