全文获取类型
收费全文 | 684篇 |
免费 | 49篇 |
专业分类
林业 | 38篇 |
农学 | 28篇 |
167篇 | |
综合类 | 28篇 |
农作物 | 44篇 |
水产渔业 | 90篇 |
畜牧兽医 | 281篇 |
园艺 | 15篇 |
植物保护 | 42篇 |
出版年
2024年 | 2篇 |
2023年 | 16篇 |
2022年 | 20篇 |
2021年 | 28篇 |
2020年 | 28篇 |
2019年 | 21篇 |
2018年 | 24篇 |
2017年 | 22篇 |
2016年 | 28篇 |
2015年 | 22篇 |
2014年 | 38篇 |
2013年 | 46篇 |
2012年 | 54篇 |
2011年 | 85篇 |
2010年 | 30篇 |
2009年 | 36篇 |
2008年 | 58篇 |
2007年 | 32篇 |
2006年 | 22篇 |
2005年 | 34篇 |
2004年 | 19篇 |
2003年 | 18篇 |
2002年 | 19篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有733条查询结果,搜索用时 15 毫秒
61.
Silvia Evangelista-Lozano Maribel Estrada-García Sandra Luz Escobar-Arellano Martha Lucia Arenas-Ocampo Brenda Hildeliza Camacho-Díaz 《Journal of plant nutrition》2015,38(4):551-567
Eucharis grandiflora Planch. and Linden is a tropical climate Amaryllidacea, commonly known as lily, which develops a bulbous stem and is considered an indoor ornamental plant for its evergreen foliage and inflorescence. The aim of this study was to evaluate the vegetative development of the Lily, in response to the treatment with of the Steiner solution at different concentrations. The plants were acclimated under greenhouse conditions and the bulbs selected by a completely randomized design. Plants were treated with various concentrations of the Steiner solution, to develop the following potential osmotic: ?0.018, ?0.036, ?0.054, ?0.072, and 0 Mpal. The production of bulbils, development and leaf area, stomatal density, chlorophyll quantification, and osmotic potentials were evaluated. The results showed that treatment with solutions of ?0.054 and ?0.072 MPa induced a greater vegetative growth, 29.5% more stomata developed, and synthesized 29% more chlorophyll “b” than the control. 相似文献
62.
Silvia Dotti Enrico Sossi Francesco Salvini Massimo Amadori 《Research in veterinary science》2011,90(2):218-8204
The purpose of this study was to evaluate the time-course of the immune response to a field Porcine Respiratory and Reproductive Syndrome virus (PRRSV) strain in PRRS-naïve, untreated pigs, as well as in four groups of age and breed-matched pigs injected with a live attenuated PRRS vaccine, its adjuvant, an inactivated PRRS vaccine and an irrelevant, inactivated Porcine Circovirus type 2 (PCV2) vaccine, respectively. PRRSV infection was confirmed in all groups by PCR and antibody assays. The antibody response measured by ELISA took place earlier in pigs injected with the live attenuated vaccine, which also developed a much stronger serum-neutralizing antibody response to the vaccine strain. Yet, no clear protection was evidenced in terms of viremia against the field virus strain, which showed 11.1% nucleotide divergence in ORF7 from the vaccine strain. In vitro, the interferon (IFN)-γ response to PRRSV was almost absent on PVD 60 in all groups under study, whereas the prevalence of interleukin (IL)-10 responses to PRRSV was fairly high in PCV2-vaccinated animals, only. Results indicate that distinct patterns of immune response to a field PRRSV strain can be recognized in PRRS-vaccinated and naïve pigs, which probably underlies fundamental differences in the development and differentiation of PRRSV-specific immune effector cells. 相似文献
63.
COMBINATION OF RADIATION THERAPY AND FIROCOXIB FOR THE TREATMENT OF CANINE NASAL CARCINOMA 下载免费PDF全文
Simona Cancedda Silvia Sabattini Giuliano Bettini Vito F. Leone Paola Laganga Federica Rossi Rossella Terragni Giacomo Gnudi Massimo Vignoli 《Veterinary radiology & ultrasound》2015,56(3):335-343
Carcinomas represent two‐thirds of canine nasosinal neoplasms. Although radiation therapy (RT) is the standard of care, the incidence of local recurrence following treatment is high. Cyclooxygenase‐isoform‐2 (COX‐2) is expressed in 71–95% of canine nasal carcinomas and has been implicated in tumor growth and angiogenesis. Accordingly, COX‐2 inhibition seems rational to improve outcome. Dogs with histologically confirmed, previously untreated nasal carcinomas were randomized to receive the combination of a selective COX‐2 inhibitor (firocoxib) and palliative RT (Group 1) or RT and placebo (Group 2). Patients were regularly monitored with blood tests, urinalysis, and computed tomography. Pet owners were asked to complete monthly a quality‐of‐life questionnaire. Twenty‐four dogs were prospectively enrolled. According to Adams modified system, there were five stage 1, five stage 2, three stage 3, and 11 stage 4 tumors. Two dogs had metastases to regional lymph nodes. Median progression‐free interval and overall survival were 228 and 335 days in Group 1 (n = 12) and 234 and 244 days in Group 2 (n = 12). These differences were not statistically significant. The involvement of regional lymph nodes was significantly associated with progression‐free interval and overall survival (P = 0.004). Quality of life was significantly improved in Group 1 (P = 0.008). In particular, a significant difference was observed for activity and appetite. Although not providing a significant enhancement of progression‐free interval and overall survival, firocoxib in combination with RT is safe and improved life quality in dogs with nasal carcinomas. 相似文献
64.
Gabriela A. Albarellos Sabrina M. Passini Martín P. Lupi Silvia Aramayona Paula M. Lorenzini Laura Montoya Maria F. Landoni 《Journal of veterinary pharmacology and therapeutics》2020,43(3):297-302
Cefuroxime axetil pharmacokinetic profile was investigated in 12 Beagle dogs after single intravenous and oral administration of tablets or suspension at a dose of 20 mg/kg, under both fasting and fed conditions. A three-period, three-treatment crossover study (IV, PO under fasting and fed condition) was applied. Blood samples were withdrawn at predetermined times over a 12-hr period. Cefuroxime plasma concentrations were determined by HPLC. Data were analyzed by compartmental analysis. No statistically significant differences were observed between formulations and feeding conditions on PK parameters. Independently of the feeding condition, absorption of cefuroxime axetil after tablet administration was low and erratic. The drug has been quantified in plasma in 3 out of 6 and 5 out of 6 dogs in the fasted and fed groups. For this formulation, the bioavailability (F), peak plasma concentration (Cmax), and area under the concentration–time curve (AUC) of cefuroxime axetil were significantly enhanced (p < .05) by the concomitant ingestion of food (32.97 ± 13.47–14.08 ± 7.79%, 6.30 ± 2.62–2.74 ± 0.66 µg/ml, and 15.75 ± 3.98–7.82 ± 2.76 µg.hr/ml for F, Cmax, and AUC in fed and fasted dogs, respectively), while for cefuroxime axetil suspension, feeding conditions affected only the rate of absorption, as reflected by the significantly shorter absorption half-life (T½(a)) and time to peak concentration (Tmax) (0.55 ± 0.27–1.15 ± 0.19 hr and 1.21 ± 0.22–1.70 ± 0.30 for T½(a) and Tmax in fed and fasted dogs, respectively). For cefuroxime axetil tablets, T > MIC (≤1 µg/ml) was <2 hr in fasted and ≈4 hr in fed animals, and for cefuroxime axetil suspension, T > MIC (≤1 µg/ml) was ≈5 hr and for T >MIC (≤4 µg/ml) was ≈2.5 hr for fasted and fed dogs, respectively. Cefuroxime axetil as a suspension formulation seems to be a better option than tablets. However, its short permanence in plasma could reduce its clinical usefulness in dogs. 相似文献
65.
Silvia Teresa Rodríguez-Ramilo Miguel Ángel Toro Jaime Castro Jesús Fernández 《Aquaculture (Amsterdam, Netherlands)》2007,273(4):434-442
Many estimators and algorithms have been developed to infer the genealogical relationships from molecular marker data when there is no pedigree information. Most pairwise methods provide estimates in a continuous range that needs to be converted into genealogical relationships (namely full-sibs, half-sibs and unrelated) if there is a previous knowledge of the population structure. Transformations are usually based on arbitrary thresholds, but the possibility of correcting the coancestry estimates via explicit pedigree reconstruction methods has been suggested. Using molecular data for ten highly polymorphic microsatellite loci on a population of turbot (Scophthalmus maximus) with a known genealogy, the behaviour of four pairwise marker-based coancestry estimators and the molecular coancestry has been evaluated. The population consisted on 138 families with 4 full-sib individuals each and one family with 8 full-sib individuals (up to 15 half-sib families were also present due to the sharing of parents between some of the full-sibs families). Our results suggested that transforming the pairwise estimators and the molecular coancestry to family relationships through the establishment of thresholds performs slightly better than the explicit pedigree reconstruction method, when accuracy is measured in a pairwise basis. However, if joint relationships between more than two individuals were tested at a time, the threshold methods led to a high percentage of incongruous triads of full-sib individuals, with Mendelian incompatibilities appearing in congruous full-sib families (more than 70% and 60% in our study, respectively). The explicit pedigree reconstruction approach, due to its nature, is free from such problems. Therefore, the pedigree reconstruction approach seems to be a valuable tool to provide a congruent and compatible pedigree when the pairwise marker-based coancestry matrices or the molecular coancestry need to be transformed. 相似文献
66.
The behavioural dynamics of fishers: management implications 总被引:4,自引:0,他引:4
In pursuing their livelihood, fishers develop strategies when faced with changes in regulations and other fishery conditions. Changes involve each individual in a decision‐making process governed by his/her own goals or constraints. Despite this reality, the complex dynamics of fishing has usually been ignored in designing management initiatives, which has contributed to management failures in many parts of the world. Fishers have generally been treated as fixed elements, with no consideration of individual attitudes based on their operating scales (geographical, ecological, social and economic) and personal goals. We review existing research on the social, economic and behavioural dynamics of fishing to provide insight into fisher behaviour and its implications for fisheries management. Emphasis is placed on fisher perception, and how fishers develop dynamic fishing tactics and strategies as an adaptive response to changes in resource abundance, environmental conditions and market or regulatory constraints. We conclude that knowledge of these dynamics is essential for effective management, and we discuss how such information can be collected, analysed and integrated into fisheries assessment and management. Particular emphasis is placed on small‐scale fisheries, but some examples from industrial fleets are provided to highlight similar issues in different types of fisheries. 相似文献
67.
Silvia Ribeiro de Souza e Silva Luiz Claúdio de Almeida Barbosa Beatriz King-Diaz Blas Lotina-Hennsen 《Pesticide biochemistry and physiology》2007,87(2):109-114
3,4-Seco-friedelan-3-oic acid was isolated from Maytenus imbricata (Celastraceae). At low concentrations it inhibited non-cyclic electron transport and ATP synthesis in spinach chloroplasts, i.e., it behaved as a Hill reaction inhibitor, and at high concentrations it acts as an uncoupler by enhancing uncoupled electron transport and Mg2+-ATPase activity. 3,4-Seco-friedelan-3-oic acid did not inhibit PSII electron transport from DPC to DCPIPox and photosystem I activity, but it enhanced from TMQH2 to MV, corroborating its action as uncoupler. It inhibits electron flow through PSII from water to sodium silicomolybdate. The whole results indicate that the 3,4-seco-friedelan-3-oic acid target is at the OEC complex enzyme, the donor side of PSII. The fluorescence decay data shows the formation of the K-band, which match this result, acting as inhibitor at the donor side of PSII and it as an uncoupler. 相似文献
68.
Simone M. Cacciò Anna Rosa Sannella Valeria Mariano Silvia Valentini Franco Berti Fabio Tosini Edoardo Pozio 《Veterinary parasitology》2013,191(1-2):128-131
An outbreak of cryptosporidiosis occurred in a mixed sheep/cattle farm of Central Italy in October 2011. A total of 450 ovines (250 sheep and 200 lambs) and 140 bovines (130 cows and 10 calves) were housed in two separated units, at the time of the outbreak. About half of the lambs had diarrhea due to Cryptosporidium sp. with a mortality rate of 80%; calves were not infected. Genomic DNA was extracted from an archived slide and from fecal specimens, and the parasite was identified as Cryptosporidium parvum by PCR and sequence analysis at the CpA135 gene. Genotyping at the GP60 gene showed the presence of a very rare genotype, IIaA20G2R1. Shortly after the outbreak was identified, the son of the farm's owner, aged 18 months, experienced an acute gastroenteritis and was hospitalized due to recurrent episodes of diarrhea, fever, vomiting and lack of appetite. The feces tested negative for bacteria and viruses, whereas cryptosporidiosis was diagnosed by microscopy and an immunochromatographic test. Molecular typing identified the C. parvum genotype IIaA20G2R1 in the feces of the child. This is the first case of transmission of cryptosporidiosis in Italy involving lambs as source of oocysts infectious to humans. 相似文献
69.
The most important active compound in garlic is alliin. Sulfur (S) fertilization was shown to significantly increase the alliin concentration in garlic cloves, while high nitrogen (N) levels had an adverse effect. The effect of graded N and S application on the storage life of garlic has been paid little attention so far. A bifactorial field trial with 4 levels of N and S was conducted in a randomized block design. At harvest, 40 bulbs per treatment were stored under terms comparable to the storage conditions in average households (20 °C, dry, and dim) for 83 days. Every 3 weeks, samples were analyzed for their alliin and water content. The alliin concentration in peeled garlic cloves increased during storage from on average 9.2 mg g(-1) dry weight at harvest to 21.4 mg g(-1) dry weight after 83 days of storage. S fertilization increased the alliin concentration by a factor of 2.3 from 11.4 mg g(-1) in the control treatment to 26.6 mg g(-1) dry weight at the highest S level of 45 kg ha(-1) after 83 days of storage. N fertilization decreased by a trend of the alliin content. Fertilizer rates had only a minor influence on water losses from bulbs at short-term storage. After 83 days of storage, water losses were by trend lower at higher S levels, and this relationship proved to be significant when no N was applied. Best quality in terms of high alliin contents was obtained during the entire storage time at an S level of at minimum 30 kg ha(-1) S if no N was applied. The results show that the physiological S demand of 15 kg ha(-1) S for optimum yield is lower than the S requirement of 30 kg ha(-1) S for a longer storage life. 相似文献
70.
Silvia Mironeasa Georgiana Gabriela Codină Silviu-Gabriel Stroe 《Communications in Soil Science and Plant Analysis》2016,47(15):1731-1737
A method for the analysis of seven mineral contents—that is, potassium (K), calcium (Ca), phosphorus (P), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu)—was investigated in some oilseeds like flax, sesame, pumpkin, quinoa, and yellow mustard. X-ray Spectral Analysis method with Spectrometer EDX-900HS was used for the analytical concentrations of the macro and micro elements of the oilseeds. A relatively high level of Zn content was found in sesame and pumpkin seeds, while the highest level of Fe content was found in mustard seeds. Regarding the macro elements (K, Ca, and P) content, the highest levels of concentration were found in flax and mustard seeds. The highest values of Cu were obtained in sesame seeds while those of Mn were in pumpkin and brown flax seeds. The results showed that the method is a reliable and simple analytical procedure to characterize mineral elements in oilseeds with a very high analytical performance. 相似文献