全文获取类型
收费全文 | 391篇 |
免费 | 17篇 |
专业分类
林业 | 32篇 |
农学 | 14篇 |
基础科学 | 1篇 |
108篇 | |
综合类 | 18篇 |
农作物 | 22篇 |
水产渔业 | 45篇 |
畜牧兽医 | 138篇 |
园艺 | 13篇 |
植物保护 | 17篇 |
出版年
2023年 | 2篇 |
2022年 | 9篇 |
2021年 | 17篇 |
2020年 | 21篇 |
2019年 | 21篇 |
2018年 | 9篇 |
2017年 | 12篇 |
2016年 | 13篇 |
2015年 | 15篇 |
2014年 | 17篇 |
2013年 | 23篇 |
2012年 | 38篇 |
2011年 | 32篇 |
2010年 | 24篇 |
2009年 | 19篇 |
2008年 | 26篇 |
2007年 | 21篇 |
2006年 | 18篇 |
2005年 | 12篇 |
2004年 | 14篇 |
2003年 | 14篇 |
2002年 | 12篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有408条查询结果,搜索用时 15 毫秒
271.
He Y Tang RH Hao Y Stevens RD Cook CW Ahn SM Jing L Yang Z Chen L Guo F Fiorani F Jackson RB Crawford NM Pei ZM 《Science (New York, N.Y.)》2004,305(5692):1968-1971
The correct timing of flowering is essential for plants to maximize reproductive success and is controlled by environmental and endogenous signals. We report that nitric oxide (NO) repressed the floral transition in Arabidopsis thaliana. Plants treated with NO, as well as a mutant overproducing NO (nox1), flowered late, whereas a mutant producing less NO (nos1) flowered early. NO suppressed CONSTANS and GIGANTEA gene expression and enhanced FLOWERING LOCUS C expression, which indicated that NO regulates the photoperiod and autonomous pathways. Because NO is induced by environmental stimuli and constitutively produced, it may integrate both external and internal cues into the floral decision. 相似文献
272.
273.
Chiara Bernardini Ester Grilli Johanna Catharina Duvigneau Augusta Zannoni Benedetta Tugnoli Fabio Gentilini Terenzio Bertuzzi Silvia Spinozzi Cecilia Camborata Maria Laura Bacci Andrea Piva Monica Forni 《Research in veterinary science》2014
Aim of this study was to characterize the effects of an ochratoxin A (181 ± 34 ng/g) contaminated diet on growth performances, blood parameters, systemic cytokine levels, cell stress markers and reactivity of immune system of weaned pigs. 相似文献
274.
Fermentation by selected sourdough lactic acid bacteria to decrease coeliac intolerance to rye flour 总被引:2,自引:0,他引:2
Maria De Angelis Rossana Coda Marco Silano Fabio Minervini Carlo G. Rizzello Raffaella Di Cagno Olimpia Vicentini Massimo De Vincenzi Marco Gobbetti 《Journal of Cereal Science》2006,43(3):301-314
A pool of selected lactic acid bacteria was used to ferment suspensions of rye flour. Two-dimensional electrophoresis showed that 109 of the 129 ethanol-soluble rye polypeptides were hydrolysed almost totally by lactic acid bacteria. Matrix-assisted laser desorption ionization—time of flight mass spectrometry and reversed-phase high performance liquid chromatography analysis confirmed the hydrolysis of prolamins. After 48 h fermentation, no prolamin polypeptides were recognized by R5-Western analysis. HPLC analysis of glutelin polymers showed a very low bacterial proteolysis but a pH dependent hydrolysis probably due to activation of rye enzymes. Prolamins were extracted from rye flour and used to produce a peptic–tryptic (PT)-digest for in vitro tests with K 562 (S) sub-clone and Caco-2/TC7 cells of human origin. The PT-digest was also treated with lactic acid bacteria before assay. The Minimal Agglutinating Capacity increased ca. 8-times when K 562 (S) sub-clone cells were exposed to rye PT-digest treated with lactic acid bacteria. Hydrolysis of rye PT-digest by lactic acid bacteria decreased the toxicity of PT-digest itself towards Caco-2/TC7 cells as estimated by cell viability, caspase-3 activity and release of nitric oxide. Rye prolamins and glutelins were extracted from doughs and subjected to PT digestion. Compared to PT-digests from chemically acidified dough, coeliac jejunal biopsies exposed to the PT-digest from the dough fermented by lactic acid bacteria did not show an increase of the infiltration of CD3+ intraepithelial lymphocytes. The same was found for epithelial cell Fas expression. Long-time fermentation of dough by selected lactic acid bacteria could be considered as a potential tool to decrease the risk of rye contamination of gluten-free products for coeliac patients. 相似文献
275.
Alessandra Mirtes Marques Neves Gon?alves Aline Brito de Lima Maria Cristina da Silva Barbosa Luiz Fernando de Camargos Júlia Teixeira de Oliveira Camila de Souza Barbosa José Augusto Ferreira Perez Villar André Carvalho Costa Isabella Viana Gomes da Silva Luciana Maria Silva Fernando de Pilla Varotti Fabio Vieira dos Santos Gustavo Henrique Ribeiro Viana 《Marine drugs》2014,12(8):4361-4378
Cancer continues to be one of the most important health problems worldwide, and the identification of novel drugs and treatments to address this disease is urgent. During recent years, marine organisms have proven to be a promising source of new compounds with action against tumoral cell lines. Here, we describe the synthesis and anticancer activity of eight new 3-alkylpyridine alkaloid (3-APA) analogs in four steps and with good yields. The key step for the synthesis of these compounds is a Williamson etherification under phase-transfer conditions. We investigated the influence of the length of the alkyl chain attached to position 3 of the pyridine ring on the cytotoxicity of these compounds. Biological assays demonstrated that compounds with an alkyl chain of ten carbon atoms (4c and 5c) were the most active against two tumoral cell lines: RKO-AS-45-1 and HeLa. Micronucleus and TUNEL assays showed that both compounds are mutagenic and induce apoptosis. In addition, Compound 5c altered the cellular actin cytoskeleton in RKO-AS-45-1 cells. The results suggest that Compounds 4c and 5c may be novel prototype anticancer agents. 相似文献
276.
277.
Gabriela C. ALVES Carlos L. R. DOS SANTOS Jerri E. ZILLI Fabio B. DOS REIS JUNIOR Ivanildo E. MARRIEL Farley A. da F. BREDA Robert M. BODDEY Veronica M. REIS 《土壤圈》2021,31(4):583-595
Diazotrophic bacteria applied as a seed inoculant can improve the grain yield of several crops including maize. The current study aimed to test the agronomic efficiency and contribution of biological nitrogen fixation(BNF) of the endophytic diazotroph Herbaspirillum seropedicae strain ZAE94 to maize under field conditions. Eighteen field assays were conducted in four different locations during consecutive years on two hybrids and two varieties of maize in a random block design with four replicates using a peat-based inoculant. The inoculant containing the ZAE94 strain was applied without nitrogen(N)fertilization or with 40 kg N ha~(-1) and was compared to the application of 40 and 80 kg N ha~(-1) without inoculation. Crop productivity and N accumulation in the grain were evaluated in addition to ~(15)N natural abundance(δ~(15)N) to evaluate BNF in the treatments without N fertilization. Fertilization at 40 kg N ha~(-1) plus bacterial inoculation produced crop yields similar to the treatment with 80 kg N ha~(-1) and increased grain N content, especially in the off-season with 40 kg N ha~(-1). The inoculation treatments showed lower δ~(15)N values than the non-inoculated treatments, which was most evident in the off-season. The BNF contributed about 30% of N accumulated in plants inoculated with ZAE94. On average, 64% of the N fertilized plots showed an increase of the parameters evaluated in the inoculated treatments, compared with the control. Inoculation also increased root length, root volume, and leaf area, and these parameters were positively correlated with plant weight using a hydroponic assay. This study revealed that the application of H. seropedicae inoculant increased the amount of N in plants owing to BNF, and there is a better chance of yield response to inoculation under low N fertilizer application in the off-season. 相似文献
278.
Elisabetta Ferro Francesco Ferrucci Enrica Zucca Viviana Di Fabio Sabrina Castoldi 《Journal of Equine Veterinary Science》2002,22(4)
In 53 racehorses with a mean age of 4.5 years old presented for poor performance, Small Airway Inflammatory Disease (SAID) was diagnosed by bronchoalveolar lavage (BAL). Thirty of these horses (58.5%) had arterial pCO2 above normal range (> 46 mmHg), while pO2 was within normal range (> 80 mmHg) in both hypercapnic (group A) and normocapnic (group B) horses although pO2 was significantly lower in group A horses. The horses were subsequently subdivided into two groups according to the duration of symptoms (group 1: less than 4 weeks; group 2: longer than 4 weeks). Horses from group 2 had significantly higher values of pCO2 (p < 0.01) , HCO3- (p < 0.01) and TCO2 (p < 0.05) when compared to horses from group 1. It was concluded that the duration of the inflammatory process may play a role in the alteration of blood/alveolar gas exchanges and acid-base status in SAID affected racehorses. 相似文献
279.
280.
A sulphate arbutin derivative was isolated from the leaves of Ilex theezans, an adulterant of mate (Ilex paraguariensis). The structure was determined by spectral analysis. 相似文献