全文获取类型
收费全文 | 1415篇 |
免费 | 119篇 |
专业分类
林业 | 120篇 |
农学 | 38篇 |
基础科学 | 2篇 |
266篇 | |
综合类 | 97篇 |
农作物 | 69篇 |
水产渔业 | 121篇 |
畜牧兽医 | 677篇 |
园艺 | 37篇 |
植物保护 | 107篇 |
出版年
2024年 | 6篇 |
2023年 | 16篇 |
2022年 | 29篇 |
2021年 | 63篇 |
2020年 | 64篇 |
2019年 | 60篇 |
2018年 | 63篇 |
2017年 | 55篇 |
2016年 | 60篇 |
2015年 | 48篇 |
2014年 | 74篇 |
2013年 | 68篇 |
2012年 | 114篇 |
2011年 | 137篇 |
2010年 | 67篇 |
2009年 | 66篇 |
2008年 | 89篇 |
2007年 | 76篇 |
2006年 | 71篇 |
2005年 | 72篇 |
2004年 | 57篇 |
2003年 | 53篇 |
2002年 | 39篇 |
2001年 | 12篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1988年 | 3篇 |
1983年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 3篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1963年 | 1篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1959年 | 1篇 |
1958年 | 3篇 |
1955年 | 1篇 |
排序方式: 共有1534条查询结果,搜索用时 15 毫秒
21.
Andrea A. Ludwig Raimund Tenhaken 《European journal of plant pathology / European Foundation for Plant Pathology》2001,107(3):323-336
Soybean (Glycine max (L.) Merill, cv. Williams 82) plants and cell cultures respond to avirulent pathogens with a hypersensitive reaction. After inoculation of soybean with Pseudomonas syringae pv. glycinea, carrying the avirulence gene avrA, or zoospores from the fungus Phytophthora sojae Race 1, a resistance-gene-dependent cell death programme is activated. A new gene was identified by differential display of mRNAs that is specifically activated during the early phase of incompatible pathogen-soybean interactions but does not respond to compatible pathogens. The gene is strongly induced within 2h after addition of P. sojae zoospores. A similar kinetic pattern was observed for P. syringae (avrA) inoculated soybean cell cultures. The gene encodes a deduced protein of 368 amino acids with a very high content of asparagine and was therefore termed N-rich protein (NRP). The protein is composed of two distinct domains, of which only the C-terminal domain has striking homology to proteins of unknown function from other plants. An antibody raised against the recombinant NRP recognizes a protein of 42kDa. The protein is located in the cell wall as indicated by cell fractionation studies. Comparison of the genomic DNA-sequence with the cDNA, identified two introns within the open reading frame. The NRP-gene is not directly induced by salicylic acid or hydrogen peroxide, indicating a distinct and specific signal transduction pathway which is only activated during programmed cell death. The NRP-gene appears to be a new marker in soybean activated early in plant disease resistance. 相似文献
22.
Andrea M. DeLuke Dave A. Allen Eric R. Wilson Jayce A. Lineberger Terry W. Lehenbauer Michelle Fabiani Brian A. Poteet 《The Canadian veterinary journal. La revue veterinaire canadienne》2012,53(10):1095-1099
Radiographic osteoarthritis scores were determined in 60 dogs up to 3 years following tibial plateau leveling osteotomy. Radiographs taken immediately following surgery and at long-term follow-up 1 to 3 years later were evaluated by 2 certified radiologists using a modified 32-point osteoarthritis scale. Changes in osteoarthritis scores were evaluated by paired t-tests and regression analysis. Sub-groups of dogs were formed to evaluate if osteoarthritis scores changed differently for follow-up periods of < 24 months compared with those > 24 months. There was a significant increase in osteoarthritis score from post-operative to follow-up evaluations for all dogs studied. Regression analysis of the relationship of months after surgery to change in osteoarthritis score was not significant. These results indicate that osteoarthritis did progress following tibial plateau leveling osteotomy, but not in a linear fashion over time. 相似文献
23.
Gesunde Pflanzen - Der Anbau von Winterraps (Brassica napus L.) wird durch das Auftreten tierischer Schaderreger begleitet, wodurch ein intensiver Insektizid-Einsatz nötig ist.... 相似文献
24.
Hector Masuh Andrea Fontn María I. Picollo Susana A. de Licastro Eduardo Zerba 《Pest management science》1996,47(2):181-184
The butyl ester of buthionine sulfoximine (BBSO) applied topically to the nymph V stage of Triatoma infestans (Klug) caused glutathione depletion which was maintained for four days after treatment. Topical pre-treatment of nymph V with BBSO significantly synergised the toxicity of DDT and fenitrothion to T. infestans. 相似文献
25.
Stability and reliability of yield and quality for 15 durum wheat genotypes (old and modern) were evaluated in a 5‐year experiment (southern Italy) in organic farming. Genotypes were grown at two N levels (0 and 80 kg/ha), with the aim of evaluating ‘genotype × environment’ (GE) interactions and their role on genotype selection in N‐limited environments. Several approaches to stability were used, within the frame of mixed models and additive main effects and multiplicative interaction analysis, and their validity in stressful conditions and organic farming was discussed. Especially for protein and gluten content, results indicate high environmental variability and the presence of crossover ‘N × environment’ interactions, which supports the need for specific breeding programmes in N‐deficient environments. The average response was strongly affected by N availability (on average, yield was 2.95 and 3.42 t/ha, protein content was 11.6% and 12.85%, gluten content was 8.55% and 9.92%, respectively, at 0 and 80 kg N/ha), and few genotypes gave high yield and quality at both fertilization levels. Only ‘Gargano’ and ‘Fortore’ showed a good inter‐year stability at both N levels. The old cultivars gave minimal responsiveness to increased N input, but gave good results in limiting conditions, indicating that they may play a role in organic farming. 相似文献
26.
Agnes Agunos Sheryl P. Gow David F. Lger Logan Flockhart Danielle Daignault Andrea Desruisseau Erin Zabek Frank Pollari Richard J. Reid-Smith 《Canadian journal of veterinary research》2021,85(1):27
Eggs are important to the diet of Canadians. This product is one of the supply-managed commodities in Canada, but unlike other commodities, where food safety risks are extensively explored and reported, information on the prevalence of enteric organisms (e.g., Salmonella, Campylobacter) and antimicrobial resistance (AMR) in layers in Canada are limited. This study was conducted to determine the prevalence of select bacteria and the associated AMR patterns in layer flocks using 2 sample matrices. Farms were located within FoodNet Canada and the Canadian Integrated Program for Antimicrobial Resistance Surveillance sentinel sites (SS). Fecal samples (Ontario: ONSS1a, ONSS1b) and environmental sponge swabs (British Columbia: BCSS2a) were collected. Salmonella prevalence was 29% and 8% in ONSS1a and ONSS1b, respectively, and 7% in BCSS2a. S. Kentucky and S. Livingstone were the most frequently isolated serovars and no S. Enteritidis was detected. Campylobacter was not detected in the BC sponge swabs but was isolated from 89% and 53% of Ontario fecal samples (ONSS1a and ONSS1b, respectively). Seven C. jejuni from Ontario were ciprofloxacin-resistant. Escherichia coli prevalence was high in both sample types (98%). Overall, tetracycline resistance among E. coli ranged from 26% to 69%. Resistance to ceftiofur (n = 2 isolates) and gentamicin (n = 2) was relatively low. There were diverse resistance patterns (excludes susceptible isolates) observed among E. coli in Ontario (10 patterns) and British Columbia (14 patterns). This study revealed that fecal samples are more informative for farm-level monitoring of pathogen and AMR prevalence. Without further validation, sponge swabs are limited in their utility for Campylobacter detection and thus, for public health surveillance. 相似文献
27.
Ferguson SM Brasnjo G Hayashi M Wölfel M Collesi C Giovedi S Raimondi A Gong LW Ariel P Paradise S O'toole E Flavell R Cremona O Miesenböck G Ryan TA De Camilli P 《Science (New York, N.Y.)》2007,316(5824):570-574
Dynamin 1 is a neuron-specific guanosine triphosphatase thought to be critically required for the fission reaction of synaptic vesicle endocytosis. Unexpectedly, mice lacking dynamin 1 were able to form functional synapses, even though their postnatal viability was limited. However, during spontaneous network activity, branched, tubular plasma membrane invaginations accumulated, capped by clathrin-coated pits, in synapses of dynamin 1-knockout mice. Synaptic vesicle endocytosis was severely impaired during strong exogenous stimulation but resumed efficiently when the stimulus was terminated. Thus, dynamin 1-independent mechanisms can support limited synaptic vesicle endocytosis, but dynamin 1 is needed during high levels of neuronal activity. 相似文献
28.
Biswajita Pradhan Rabindra Nayak Prajna Paramita Bhuyan Srimanta Patra Chhandashree Behera Sthitaprajna Sahoo Jang-Seu Ki Alessandra Quarta Andrea Ragusa Mrutyunjay Jena 《Marine drugs》2022,20(6)
The increasing drug resistance of infectious microorganisms is considered a primary concern of global health care. The screening and identification of natural compounds with antibacterial properties have gained immense popularity in recent times. It has previously been shown that several bioactive compounds derived from marine algae exhibit antibacterial activity. Similarly, polyphenolic compounds are generally known to possess promising antibacterial capacity, among other capacities. Phlorotannins (PTs), an important group of algae-derived polyphenolic compounds, have been considered potent antibacterial agents both as single drug entities and in combination with commercially available antibacterial drugs. In this context, this article reviews the antibacterial properties of polyphenols in brown algae, with particular reference to PTs. Cell death through various molecular modes of action and the specific inhibition of biofilm formation by PTs were the key discussion of this review. The synergy between drugs was also discussed in light of the potential use of PTs as adjuvants in the pharmacological antibacterial treatment. 相似文献
29.
Valeria Villanova Christian Galasso Giovanni Andrea Vitale Gerardo Della Sala Johan Engelbrektsson Niklas Strmberg Kashif Mohd Shaikh Mats X. Andersson Fortunato Palma Esposito Susanne Ekendahl Donatella De Pascale Cornelia Spetea 《Marine drugs》2022,20(7)
A local strain of Nannochloropsis granulata (Ng) has been reported as the most productive microalgal strain in terms of both biomass yield and lipid content when cultivated in photobioreactors that simulate the light and temperature conditions during the summer on the west coast of Sweden. To further increase the biomass and the biotechnological potential of this strain in these conditions, mixotrophic growth (i.e., the simultaneous use of photosynthesis and respiration) with glycerol as an external carbon source was investigated in this study and compared with phototrophic growth that made use of air enriched with 1–2% CO2. The addition of either glycerol or CO2-enriched air stimulated the growth of Ng and theproduction of high-value long-chain polyunsaturated fatty acids (EPA) as well as the carotenoid canthaxanthin. Bioassays in human prostate cell lines indicated the highest antitumoral activity for Ng extracts and fractions from mixotrophic conditions. Metabolomics detected betaine lipids specifically in the bioactive fractions, suggesting their involvement in the observed antitumoral effect. Genes related to autophagy were found to be upregulated by the most bioactive fraction, suggesting a possible therapeutic target against prostate cancer progression. Taken together, our results suggest that the local Ng strain can be cultivated mixotrophically in summer conditions on the west coast of Sweden for the production of high-value biomass containing antiproliferative compounds, carotenoids, and EPA. 相似文献
30.
Andrea Brandolini Alyssa Hidalgo Salvatore Moscaritolo 《Journal of Cereal Science》2008,47(3):599-609
Einkorn (Triticum monococcum L. subsp. monococcum) is an ancient wheat appreciated for its high proteins, carotenoids and tocols content. To better understand its potential for human consumption and food preparation, composition and pasting properties of 65 einkorn accessions, of different geographical origin but cultivated at S. Angelo Lodigiano (Italy), were evaluated. Eight Triticum turgidum and seven Triticum aestivum cultivars, belonging to different subspecies, were assessed as controls.On average, the einkorn samples had light seeds (25.0 mg/kernel), extra-soft texture (238.3 g), high protein content (18.2%), high ash content (2.35%), low SDS sedimentation volume (25.6 ml), high carotenoids (8.36 μg/g) and high yellow pigments (8.46 μg/g). The pasting parameters studied were peak viscosity (average: 2426 cP), breakdown (765 cP), final viscosity (2788 cP) and setback (1126 cP). Total amylose (25.7%) and total starch (65.5%) were also measured. Significant differences from the controls and a broad variation for all the traits analysed were observed. Einkorns from diverse geographical areas showed different mean values for all characters, apart from ash content.The good pasting properties, coupled with high proteins and carotenoids content, suggest that einkorn is particularly suited for the production of baby and specialty foods. 相似文献