全文获取类型
收费全文 | 10062篇 |
免费 | 495篇 |
国内免费 | 505篇 |
专业分类
林业 | 1583篇 |
农学 | 751篇 |
基础科学 | 295篇 |
959篇 | |
综合类 | 3677篇 |
农作物 | 694篇 |
水产渔业 | 255篇 |
畜牧兽医 | 1263篇 |
园艺 | 1155篇 |
植物保护 | 430篇 |
出版年
2024年 | 68篇 |
2023年 | 261篇 |
2022年 | 378篇 |
2021年 | 300篇 |
2020年 | 396篇 |
2019年 | 410篇 |
2018年 | 308篇 |
2017年 | 354篇 |
2016年 | 363篇 |
2015年 | 358篇 |
2014年 | 414篇 |
2013年 | 512篇 |
2012年 | 574篇 |
2011年 | 525篇 |
2010年 | 405篇 |
2009年 | 648篇 |
2008年 | 412篇 |
2007年 | 429篇 |
2006年 | 384篇 |
2005年 | 335篇 |
2004年 | 438篇 |
2003年 | 275篇 |
2002年 | 292篇 |
2001年 | 222篇 |
2000年 | 262篇 |
1999年 | 162篇 |
1998年 | 135篇 |
1997年 | 133篇 |
1996年 | 271篇 |
1995年 | 184篇 |
1994年 | 153篇 |
1993年 | 122篇 |
1992年 | 116篇 |
1991年 | 72篇 |
1990年 | 69篇 |
1989年 | 41篇 |
1988年 | 65篇 |
1987年 | 20篇 |
1986年 | 23篇 |
1985年 | 24篇 |
1984年 | 22篇 |
1983年 | 24篇 |
1982年 | 17篇 |
1981年 | 20篇 |
1980年 | 16篇 |
1979年 | 31篇 |
1978年 | 15篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
随着国家经济发展的迅速和人口的不断增长,农业的发展越来越受到人们的重视,因此农业的发展关乎着国家的命脉,如何利用科学技术来帮助农业的发展成为人们研究的方向。在农业发展的过程中,对果树的病虫害防治是非常重要的环节,这对果树的健康和产量都有很大的影响。因此,本文对蜜柚进行了深入的研究,分析了蜜柚病虫害特点和科学防治的方法。意在为蜜柚增产提供帮助。 相似文献
42.
43.
44.
45.
Xiao-feng YUE Yan-lun JU Zi-zhu TANG Ya-meng ZHAO Xu-liang JIAO Zhen-wen ZHANG 《农业科学学报》2019,18(9):2052-2062
The effects of the severity and timing of leaf removal(LR) on the amino acids of Sauvignon Blanc grapes and wines were studied during the 2017 growing season. High-performance liquid chromatography(HPLC) was used to analyze the amino acids profiles of grape berries and wines. The basal leaves were removed at three time points(40, 56 and 72 days after flowering, named LR40, LR56 and LR72, respectively) at two severity levels(one at which the first, third, and fifth basal leaves of each shoot were removed(50% level); and another at which the first six basal leaves were removed(100% level)). The results showed that leaf removal had little impact on total soluble solids(°Brix), titratable acidity, pH or berry weight. The LR72-50% treated grapes had higher berry weight, titratable acidity and °Brix than those of the other treatments. The highest concentrations of total amino acids and of total amino acids except proline were detected in LR72-50% treated grapes(2 952.58 and 2 764.36 mg L~(-1), respectively); the lowest were detected in LR72-100% treated grapes(2 172.82 and 2 038.71 mg L~(-1), respectively). LR72-50% treatment significantly promoted the synthesis of aspartic acid, serine, arginine, alanine, aminobutyric acid and proline at both severity levels for grapes, the concentrations of all of these amino acids were increased relative to the control concentrations. The LR72-50%, LR40-100% and LR72-100% treated wines had higher total amino acids concentrations and higher concentrations of some individual amino acids, such as arginine, alanine and serine, than did the control wines. Of all the amino acids studied, glycine, tyrosine, cysteine, methionine and lysine were not significantly influenced by the timing or severity basal defoliation in grapes and wines. The present study reveals the effects of the timing and severity of leaf removal on the amino acids profiles of grapes and wines. 相似文献
46.
47.
秸秆还田配施腐熟剂对砂性土壤性质及滴灌玉米生长的影响 总被引:2,自引:0,他引:2
为探究秸秆还田配施腐熟剂对宁夏扬黄灌区土壤改良和玉米增产的效应,在秸秆还田条件下施用3种不同腐熟剂[生物秸秆速腐剂(SR+BS)、EM菌秸秆腐熟剂(SR+RJ)、有机废物发酵菌曲(SR+OW)],以秸秆还田不施腐熟剂处理为对照(CK),研究其对秸秆生物失重率、砂性土壤理化性状和滴灌玉米生长及产量的影响。结果表明,3种腐熟剂均能有效促进玉米秸秆腐解,其中SR+RJ的秸秆腐解程度最佳,翻埋130 d后其秸秆生物失重率为49.9%,SR+OW和SR+BS次之,3种处理分别较CK显著提高7.1、5.7、5.2个百分点。SR+RJ对改善0~40 cm土层土壤容重效果最佳,较CK显著降低4.2%,同时显著提高了耕层土壤有机质和速效养分含量及生育中后期土壤贮水量,SR+OW和SR+BS次之。施用秸秆腐熟剂能明显促进玉米生育中后期植株生长,其中SR+RJ最佳。SR+RJ和SR+OW对玉米增产增收效果最明显,分别较CK显著增产26.9%、23.4%,显著增收28.8%、23.4%。可见,秸秆还田配施腐熟剂可有效促进玉米秸秆腐解,改善土壤理化性质,促进玉米生长发育,显著提高作物产量与经济效益,以EM菌秸秆腐熟剂效果最佳。本研究为宁夏扬黄灌区还田后促进秸秆腐熟和砂性土壤培肥及玉米高产提供了技术参考。 相似文献
48.
金花茶对低温胁迫的生理响应及耐寒性分析 总被引:1,自引:0,他引:1
为探究金花茶幼苗对低温胁迫的生理响应及其耐寒性,本研究以2 a生金花茶幼苗为材料,进行6~-9℃低温胁迫处理,测定了细胞伤害率(CIR)、丙二醛(MDA)、过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、束缚水(BW)/自由水(FW)、脯氨酸(Pro)、可溶性糖(SS)等指标,并进行了低温半致死温度(LT50)和抗寒生理指标相关性分析。结果表明,3~12 h的低温LT50为-6.62~-3.94℃,且随着时间的延长而升高。随着温度的降低, CIR、SS含量及POD、CAT活性总体呈上升趋势, BW/FW、MDA、Pro含量呈先上升后下降趋势, SOD活性总体呈下降趋势;随着胁迫时间的延长,CIR含量呈上升趋势,3~-9℃的SOD活性、0~-9℃的POD活性、-6~-9℃的BW/FW比值呈下降趋势,6~-6℃的SS含量变化较小,-9℃的SS含量呈下降趋势。相关性分析表明,CIR可作为耐寒性鉴定的主要指标,BW、SS、SOD、POD、CAT可作为辅助指标。本研究结果为金花茶引种区域和耐寒性鉴定指标的确定提供了理论依据。 相似文献
49.
Umesh PANKAJ Durgesh Narain SINGH Pooja MISHRA Pooja GAUR C. S. Vivek BABU Karuna SHANKER Rajesh Kumar VERMA 《土壤圈》2020,30(5):671-683
Phytoremediation is a promising approach for reclamation of salt-affected soil. Phytoextraction is the most commonly used process, which exploits plants to absorb, immobilize, and accumulate salt in their shoots. In this study, halotolerant plant growth-promoting rhizobacteria (PGPR) were isolated from the rhizosphere of wild grasses growing naturally in salt-affected areas of Lucknow, Uttar Pradesh (India) and were tested for their efficacies of salt-tolerance and plant growth-promoting (PGP) abilities. Based on 16S rRNA sequences, the most efficient halotolerant isolates possessing PGP traits were identified as Pseudomonas plecoglossicida (KM233646), Acinetobacter calcoaceticus (KM233647), Bacillus flexus (KM233648), and Bacillus safensis (KM233652). Application of these isolates as bio-inoculants significantly (P < 0.05) increased the growth and bacoside A yield of a medicinal plant, Bacopa monnieri (L.) Nash, grown on natural salt-affected soil. The phytoremediation of salt-affected soil was evident by the substantial increase in shoot Na+:K+ ratio of bio-inoculant-treated plants. When compared to un-inoculated control plants, the soil physico-chemical properties of bio-inoculant-treated plants were improved. The shoot and root biomass (fresh and dry weights), soil enzymes, and soil nutrient parameters showed significant positive correlations with the shoot Na+:K+ ratio. Consequently, the halotolerant PGPR screened in this study could be useful for the reclamation of saline soils concomitant with improved plant growth and bacoside A yield. 相似文献
50.
在分析食用菌产品专业术语翻译现状的基础上,详细讨论了翻译的准确性、国际贸易的语场和文化差异。提出尊重当地文化传统和语言习惯、遵守国际贸易中的"专业术语",注重翻译准确性和专业性的翻译策略,消除食用菌产品出口贸易中的语言障碍,更好地服务于食用菌产业的发展。 相似文献