全文获取类型
收费全文 | 504篇 |
免费 | 55篇 |
专业分类
林业 | 46篇 |
农学 | 20篇 |
基础科学 | 4篇 |
81篇 | |
综合类 | 33篇 |
农作物 | 21篇 |
水产渔业 | 90篇 |
畜牧兽医 | 208篇 |
园艺 | 6篇 |
植物保护 | 50篇 |
出版年
2024年 | 2篇 |
2023年 | 16篇 |
2022年 | 17篇 |
2021年 | 27篇 |
2020年 | 41篇 |
2019年 | 41篇 |
2018年 | 34篇 |
2017年 | 32篇 |
2016年 | 29篇 |
2015年 | 21篇 |
2014年 | 19篇 |
2013年 | 26篇 |
2012年 | 29篇 |
2011年 | 53篇 |
2010年 | 24篇 |
2009年 | 19篇 |
2008年 | 23篇 |
2007年 | 22篇 |
2006年 | 17篇 |
2005年 | 12篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 7篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1984年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1975年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1967年 | 2篇 |
1965年 | 1篇 |
1957年 | 1篇 |
1956年 | 1篇 |
1953年 | 2篇 |
1940年 | 1篇 |
排序方式: 共有559条查询结果,搜索用时 15 毫秒
121.
Vanessa S. Rizzo-Valente Maria A. Fusco Renata M. M. L. Cruz Rachel A. Santos Lucas S. Silva Roberta C. Escaleira Daniel F. Schulz Shana P. C. Barroso Bruno L. Miranda Daniela Z. Santos Marcelo L. Gregrio Rodrigo J. A. Guerra Mauro S. G. Pavo 《Marine drugs》2022,20(11)
Acute and chronic dermatological injuries need rapid tissue repair due to the susceptibility to infections. To effectively promote cutaneous wound recovery, it is essential to develop safe, low-cost, and affordable regenerative tools. Therefore, we aimed to identify the biological mechanisms involved in the wound healing properties of the glycosaminoglycan dermatan sulfate (DS), obtained from ascidian Styela plicata, a marine invertebrate, which in preliminary work from our group showed no toxicity and promoted a remarkable fibroblast proliferation and migration. In this study, 2,4-DS (50 µg/mL)-treated and control groups had the relative gene expression of 84 genes participating in the healing pathway evaluated. The results showed that 57% of the genes were overexpressed during treatment, 16% were underexpressed, and 9.52% were not detected. In silico analysis of metabolic interactions exhibited overexpression of genes related to: extracellular matrix organization, hemostasis, secretion of inflammatory mediators, and regulation of insulin-like growth factor transport and uptake. Furthermore, in C57BL/6 mice subjected to experimental wounds treated with 0.25% 2,4-DS, the histological parameters demonstrated a great capacity for vascular recovery. Additionally, this study confirmed that DS is a potent inducer of wound-healing cellular pathways and a promoter of neovascularization, being a natural ally in the tissue regeneration strategy. 相似文献
122.
Sandra Godinho Silva Patrícia Paula Jos Paulo da Silva Dalila Mil-Homens Miguel Cacho Teixeira Arsnio Mendes Fialho Rodrigo Costa Tina Keller-Costa 《Marine drugs》2022,20(7)
Two novel natural products, the polyketide cuniculene and the peptide antibiotic aquimarin, were recently discovered from the marine bacterial genus Aquimarina. However, the diversity of the secondary metabolite biosynthetic gene clusters (SM-BGCs) in Aquimarina genomes indicates a far greater biosynthetic potential. In this study, nine representative Aquimarina strains were tested for antimicrobial activity against diverse human-pathogenic and marine microorganisms and subjected to metabolomic and genomic profiling. We found an inhibitory activity of most Aquimarina strains against Candida glabrata and marine Vibrio and Alphaproteobacteria species. Aquimarina sp. Aq135 and Aquimarina muelleri crude extracts showed particularly promising antimicrobial activities, amongst others against methicillin-resistant Staphylococcus aureus. The metabolomic and functional genomic profiles of Aquimarina spp. followed similar patterns and were shaped by phylogeny. SM-BGC and metabolomics networks suggest the presence of novel polyketides and peptides, including cyclic depsipeptide-related compounds. Moreover, exploration of the ‘Sponge Microbiome Project’ dataset revealed that Aquimarina spp. possess low-abundance distributions worldwide across multiple marine biotopes. Our study emphasizes the relevance of this member of the microbial rare biosphere as a promising source of novel natural products. We predict that future metabologenomics studies of Aquimarina species will expand the spectrum of known secondary metabolites and bioactivities from marine ecosystems. 相似文献
123.
Andrei D. Zdziarski Leomar G. Woyann Anderson S. Milioli Rodrigo Zanella Lucas V. Dallacorte Maiara C. Panho Giovani Benin 《Plant Breeding》2019,138(3):336-347
Mega‐environment (ME) identification is the first step for evaluating, selecting and recommending genotypes within a target region (TR). The present study aimed to (a) identify MEs, using GGE biplot methods, in Brazilian edaphoclimatic region (ECR) 402 of soybean cultivation, located in the Mato Grosso State (the TR) and (b) compare the performance of genotypes within the TR and in each ME using fixed and mixed models. Data from three years of soybean yield trials, 19 genotypes and 22 environments were used. The biplots GGE, GGL + GGE and GGS + GGE were implemented to identify the MEs. Two MEs were identified in the TR. ME1 presents a higher altitude, farms which use a higher level of fertilizer inputs and a higher occurrence of the soybean cyst nematode (SCN) than ME2. When selection and recommendation are made based on MEs, genotypes with both broadly and specific adaptation can be selected. This action can improve grain yield in the entire target region. 相似文献
124.
125.
Cisneros A Mazzanti G Campos R Marangoni AG 《Journal of agricultural and food chemistry》2006,54(16):6030-6033
The kinetics of crystallization of high-melting fraction (HMF) and a mixture of 40% HMF and 60% low-melting fraction (LMF) of milk fat were studied at 5 degrees C by time-resolved in-situ synchrotron X-ray diffraction. HMF crystallized in the alpha polymorph, had a longer lifetime than the ones previously reported in pure milk fat, and was almost completely solid. The HMF/LMF mixture crystallized initially in the alpha form and transformed into the beta' polymorph, with a solid fat content much lower than that of HMF. The polymorphic change was therefore attributed to a delayed sudden formation of beta' mixed crystals from the uncrystallized melt. These findings are important for the food industry and as fundamental knowledge to improve our understanding of the origin of the macroscopic physical properties of solid milk fat fractions used in many manufacturing processes. 相似文献
126.
Sanchez-Ballesta MT Rodrigo MJ Lafuente MT Granell A Zacarias L 《Journal of agricultural and food chemistry》2004,52(7):1950-1957
A cDNA encoding a dehydrin was isolated from the flavedo of the chilling-sensitive Fortune mandarin fruit (Citrus clementina Hort. Ex Tanaka x Citrus reticulata Blanco) and designed as Crcor15. The predicted CrCOR15 protein is a K2S member of a closely related dehydrin family from Citrus, since it contains two tandem repeats of the unusual Citrus K-segment and one S-segment (serine cluster) at an unusual C-terminal position. Crcor15 mRNA is consistently and highly expressed in the flavedo during fruit development and maturation. The relative abundance of Crcor15 mRNA in the flavedo was estimated to be higher than 1% of total RNA. The high mRNA level remained unchanged during fruit storage at chilling (2 degrees C) and nonchilling (12 degrees C) temperatures, and it was depressed by a conditioning treatment (3 days at 37 degrees C) that induced chilling tolerance. Therefore, the expression of Crcor15 appears not to be related to the acquisition of chilling tolerance in mandarin fruits. However, Crcor15, which was barely detected in unstressed mandarin leaves, was rapidly induced in response to both low temperature and water stress. COR15 protein was expressed in Escherichia coli, and the purified protein conferred in vitro protection against freezing and dehydration inactivation. The potential role of Citrus COR15 is discussed. 相似文献
127.
Cantera RG Zamarreño AM García-Mina JM 《Journal of agricultural and food chemistry》2002,50(26):7609-7615
Iron deficiency is a common problem for many plants grown in alkaline and calcareous soils. To correct this problem, iron is supplied to plants as chelates. Several iron chelates are sold under diverse trademarks with different characteristics. This work evaluated 18 commercial products containing the most representative chelated iron sources used in agricultural practice in Spain when the study was done, namely the ferric chelates of EDDHA, EDDHMA, EDDCHA, EDDHSA, EDTA, and DTPA. The chelates were comprehensively characterized and quantitated by several techniques, including several chromatographic methods. Iron and chelate dynamics in soil were also studied in a model alkaline and calcareous soil. Results indicate that, in this model soil, among the different iron compounds studied only FeEDDHA and analogues have the capacity to maintain soluble iron in soil solution over time. These results are in agreement with general experience under field conditions. Furthermore, among the different ortho-ortho isomers of FeEDDHA's, FeEDDHSA and FeEDDCHA showed greater capacity than FeEDDHA and FeEDDHMA to maintain the chelated iron in soil solution over time. 相似文献
128.
Rodrigo Barba-Gonzalez Alex A. Van Silfhout Richard G. F. Visser Munikote S. Ramanna Jaap M. Van Tuyl 《Euphytica》2006,151(2):243-250
With the aim of utilizing allotriploid (2n = 3x = 36) lily hybrids (Lilium) in introgression breeding, different types of crosses were made. First, using diploid Asiatic lilies (2n = 2x = 24), reciprocal crosses (3x − 2x and 2x − 3x) were made with allotriploid hybrids (AOA) obtained by backcrosses of F1 Oriental × Asiatic hybrids (OA) to Asiatic cultivars (A). Secondly, the AOA allotriploids were crossed with allotetraploid (OAOA, 2n = 4x = 48), in 3x − 4x combination. Finally, the AOA allotriploids where crossed to 2n gamete producer F1 OA hybrids (3x − 2x (2n)). Two types of triploids were used as parents in the different types of crosses, derived from: (a) mitotic polyploidization and (b) sexual polyploidization. Ploidy level of the progeny was determined by estimating the DNA values through flowcytometry as well as chromosome counting. The aneuploid progeny plants from 3x − 2x and reciprocal crosses had approximate diploid levels and in 3x − 4x crosses and 3x − 2x (2n) the progeny had approximate tetraploid levels. Balanced euploid gametes (x, 2x and 3x) were formed in the AOA genotypes. Recombinant chromosomes were found in the progenies of all crosses, except in the case of 2x − 3x crosses through genomic in situ hybridization (GISH) analyses. Recombinant chromosomes occurred in the F1 OA hybrid when the triploid AOA hybrid was derived through sexual polyploidization, but not through mitotic polyploidization with two exceptions. Those recombinant chromosomes were transmitted to the progenies in variable frequencies. 相似文献
129.
von Bernuth H Picard C Jin Z Pankla R Xiao H Ku CL Chrabieh M Mustapha IB Ghandil P Camcioglu Y Vasconcelos J Sirvent N Guedes M Vitor AB Herrero-Mata MJ Aróstegui JI Rodrigo C Alsina L Ruiz-Ortiz E Juan M Fortuny C Yagüe J Antón J Pascal M Chang HH Janniere L Rose Y Garty BZ Chapel H Issekutz A Maródi L Rodriguez-Gallego C Banchereau J Abel L Li X Chaussabel D Puel A Casanova JL 《Science (New York, N.Y.)》2008,321(5889):691-696
MyD88 is a key downstream adapter for most Toll-like receptors (TLRs) and interleukin-1 receptors (IL-1Rs). MyD88 deficiency in mice leads to susceptibility to a broad range of pathogens in experimental settings of infection. We describe a distinct situation in a natural setting of human infection. Nine children with autosomal recessive MyD88 deficiency suffered from life-threatening, often recurrent pyogenic bacterial infections, including invasive pneumococcal disease. However, these patients were otherwise healthy, with normal resistance to other microbes. Their clinical status improved with age, but not due to any cellular leakiness in MyD88 deficiency. The MyD88-dependent TLRs and IL-1Rs are therefore essential for protective immunity to a small number of pyogenic bacteria, but redundant for host defense to most natural infections. 相似文献
130.
Leonardo Vilela Junqueira Rodrigo Nogueira de Sousa Cassio de Souza Almeida Felipe Gimenes Alonso Valdemar Luiz Tornisielo 《Archives of Agronomy and Soil Science》2020,66(12):1651-1667
ABSTRACT The objective of this study was to evaluate the sorption-desorption process and biodegradation of glyphosate in two tropical soils aged with biochar derived from eucalyptus. The biochar aging period was 30 d. There was little difference between the amounts of sorbed glyphosate in Ultisol (96.8, 96.8 and 96.4%) and Alfisol (97.1, 97.5 and 97.4%) soils that were unamended or amended with biochar aged for 0 or 30 d, respectively. Similar amounts of desorbed herbicide occurred in Ultisol (3.3, 3.3 and 3.4%) and Alfisol (4.1, 4.2 and 3.9%) soils, respectively. The degradation time half-life (DT50) of glyphosate in Ultisol unamended and initial amended were higher (38 and 36 d, respectively) than DT50 in the amended soil with 30 d of biochar aging (27 d); and in the Alfisol DT50 was higher in unamended soil (38 d), and similar in soil unamended at 0 and 30 d of biochar aging (21 and 26 d, respectively). The addition of biochar to two tropical soils or its aging did not have any effect on the sorption and desorption of glyphosate and its biodegradation in relation to the unamended soils, and it can did not affect the transport and persistence of this herbicide in soil. 相似文献