全文获取类型
收费全文 | 516篇 |
免费 | 38篇 |
专业分类
林业 | 37篇 |
农学 | 17篇 |
基础科学 | 4篇 |
162篇 | |
综合类 | 17篇 |
农作物 | 29篇 |
水产渔业 | 43篇 |
畜牧兽医 | 162篇 |
园艺 | 20篇 |
植物保护 | 63篇 |
出版年
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 21篇 |
2020年 | 19篇 |
2019年 | 19篇 |
2018年 | 13篇 |
2017年 | 20篇 |
2016年 | 16篇 |
2015年 | 3篇 |
2014年 | 12篇 |
2013年 | 38篇 |
2012年 | 32篇 |
2011年 | 45篇 |
2010年 | 17篇 |
2009年 | 22篇 |
2008年 | 32篇 |
2007年 | 37篇 |
2006年 | 26篇 |
2005年 | 30篇 |
2004年 | 28篇 |
2003年 | 13篇 |
2002年 | 23篇 |
2001年 | 10篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1969年 | 2篇 |
1963年 | 2篇 |
1961年 | 1篇 |
排序方式: 共有554条查询结果,搜索用时 15 毫秒
71.
Hugo Vilhena Asta Tvarijonaviciute Jos J. Cern Ana C. Figueira Snia Miranda Ana Ribeiro Ana Canadas Patrícia Dias‐Pereira Camila P. Rubio Lorena Franco Fernando Tecles Ricardo Cabeas Josep Pastor Ana C. Silvestre‐Ferreira 《Veterinary and comparative oncology》2019,17(3):394-406
Acute phase proteins (APP) and biomarkers of oxidative status change in human and canine mammary tumours, however, they have not been studied in feline mammary tumours. The aims of this study were to investigate the APP and antioxidant responses in feline malignant mammary tumours, to evaluate their relation with tumour features, and to assess their prognostic value. Serum amyloid A (SAA), haptoglobin (Hp), albumin, butyrylcholinesterase (BChE), insulin‐like growth factor1 (IGF1), paraoxonase1 (PON1), total serum thiols (Thiol), glutathione peroxidase (GPox) and total antioxidant capacity determined by different assays, including trolox equivalent antioxidant capacity assessed by two different methodologies (TEAC1/2), ferric reducing ability of plasma (FRAP), and cupric reducing antioxidant capacity (CUPRAC), were determined in serum of 50 queens with spontaneous mammary carcinomas and of 12 healthy female cats. At diagnosis, diseased queens presented significantly higher SAA and Hp, and lower albumin, BChE, GPox, TEAC1, TEAC2 and CUPRAC than controls. Different tumour features influenced concentrations of APP and antioxidants. Increases in serum Hp, and decreases in albumin, Thiol and FRAP were significantly associated with neoplastic vascular emboli, metastasis in regional lymph nodes and/or in distant organs. Distant metastasis development during the course of the disease was associated with increases in SAA and TEAC1. At diagnosis, decreased albumin was associated with a longer survival, and BChE <1.15 μmoL/mL.minute was associated with a shorter survival time on multivariate analysis. Feline malignant mammary tumours are associated with an APP response and oxidative stress, and different tumour features influence the inflammatory response and the oxidative damage. Furthermore, some of these analytes proved to have prognostic value. 相似文献
72.
Lucia Prellwitz Fabiana Nunes Zambrini Jos Domingos Guimares Marco Antonio Paula de Sousa Maria Emília Franco Oliveira Alexandre Rosetto Garcia Srgio Novita Esteves Pawel Mieczyslaw Bartlewski Joanna Maria Gonalves Souza‐Fabjan Jeferson Ferreira Fonseca 《Reproduction in domestic animals》2019,54(9):1230-1235
This study compared the effects of intravaginal and intravenous routes of oxytocin (OT) administration in 46 oestrous‐induced Santa Inês ewes (6‐day treatment with progestin‐releasing intravaginal sponges and a single injection of 200 IU of eCG at the time of sponge removal) that underwent transcervical embryo recovery 6–7 days after oestrous onset and mating. All ewes received 37.5 μg of d‐cloprostenol via latero‐vulvar route, and 1 mg of oestradiol benzoate i.m. 16 hr before and 50 IU of OT 20 min before non‐surgical embryo recovery (NSER), with OT being administered intravenously (n = 21) or intravaginally (n = 21). An overall oestrous response was 95.6% (44/46), and adequate cervical retraction could be accomplished in 78.6% (33/42) of ewes. The percentage of successful NSER procedures was 57% (24/42) or 72.7% (24/33) of animals with sufficient cervical retraction. The duration of NSER procedure averaged 28 min (range: 17–40 min) and ~96% of flushing fluid could be recovered (range: 85%–100%). Out of 18 ewes that could not undergo NSER, 12 (66.6%) presented various anatomical barriers, whilst the other 33.4% did not present these barriers and still could not be traversed. Excluding the ewes with those anatomical features, the overall success rate of NSER was 80% (24/30). The route of OT administration had no effect on NSER efficiency or the ease with which transcervical embryo flushing was performed. Both routes of OT administration can be used for cervical dilation protocol. Discarding ewes with anatomical features precluding cervical penetration is highly recommended to increase the efficacy of NSER in sheep. 相似文献
73.
Inteeworn N Ohlerth S Höpfl G Guscetti F Bley CR Wergin MC Roos M Gassmann M Kaser-Hotz B 《Veterinary journal (London, England : 1997)》2007,173(3):564-570
PTK787/ZK 222584 is an inhibitor of the vascular endothelial growth factor (VEGF) receptor tyrosine kinases. In this study, the effectiveness of PTK787/ZK 222584 and radiation on canine oral melanoma xenografts was assessed. Xenografts were treated with radiotherapy (4x6Gy), or with PTK787/ZK 222584, or with a combination of both. Treatment efficacy was assessed using a tumour growth delay assay, serial power Doppler and pO(2) measurements during and after therapy. There was a significant growth delay for the group treated with radiation alone and for the combined treatment group. However, tumour growth delay was similar in both groups. Tumours were hypoxic before irradiation and no significant re-oxygenation occurred during therapy. In all tumours, vascularity and perfusion were significantly lower at the end of the study but no significant differences in perfusion, vascularity and oxygenation status were observed between and within treatment groups. The combination of PTK787/ZK 222584 and radiotherapy did not perform better than radiotherapy alone in this model. 相似文献
74.
Significant improvement of shrimp growth performance by growth hormone‐releasing peptide‐6 immersion treatments 下载免费PDF全文
Amílcar Arenal Juana María Lugo Reynold Morales Leonardo Martín Ramón Franco Rodríguez Jannel Acosta Antonio Morales Jorge Duconge Mario Pablo Estrada 《Aquaculture Research》2017,48(9):4632-4645
Growth hormone‐releasing peptide‐6 (GHRP‐6) is one of the earliest developed synthetic peptidyl growth hormone secretagogue receptor agonists. These compounds mimic the effect of the endogenous ligand ghrelin. In vertebrates, ghrelin is a potent circulating orexigenic hormone with functional roles in controlling food intake, energy expenditure, adiposity, growth hormone secretion and immunity. Ghrelin has been studied mainly in vertebrates; thus, little is known about its role in invertebrates, including crustaceans. We first evaluated the effect of GHRP‐6 injection over feed intake in shrimp and its effects on shrimp growth when the peptide was administrated by successive immersion baths. GHRP‐6 increased feed intake, body weight and size, the number of rostral spines and gill branches, protein concentration and haemocyte number in treated shrimps. We also evaluated the peptide uptake and clearance in a pharmacokinetics, using [H3]GHRP‐6 administered to postlarvae. Given a limited exposure and efficient clearance of the peptide‐associated radioactivity from larvae, our findings suggested that GHRP‐6‐treated Litopenaeus vannamei can be consumed safely by humans after aquaculture applications. These results propose that GHRP‐6 could be an additional tool to study growth physiology in crustaceans and also a promising candidate for development into a new biotechnology product for improving shrimp growth and quality. 相似文献
75.
76.
Milagros R. de la Peña Annie Villa Franco Hermoso P. IgcasanJr Mary Dianne Grace N. Arnaldo Ramil M. Piloton Soledad S. Garibay Vicente T. Balinas 《Aquaculture International》2018,26(4):1119-1134
The optimum culture conditions of the local strain Chaetoceros calcitrans were determined to improve biomass and reduce cost of production. Under outdoor culture conditions, higher cell density was attained when the cultures were enriched with Tungkang Marine Research Laboratory (TMRL) medium composed of cheap technical grade reagents and cultured at 25 g L?1 salinity. The cultures were lighted with two 40 W cool-white GE fluorescent tubes (24–35 μmol photon m?2 s?1). Using semi-continuous culture system under established optimum culture conditions, C. calcitrans can be re-cultured thrice and concentrated at each culture cycle using electrolytic flocculation method to produce 4.6 kg m?3 of diatom paste. The viability of concentrated C. calcitrans after 3 months of storage was comparable to live diatom cells. Simple preservation technique by low-temperature storage is convenient for storing algal concentrates for use as starter cultures and for feeding invertebrates. The paste costs USD 8.24 kg?1 inclusive of the assets and flocculation materials for culturing and harvesting the diatom, respectively. This study established the suitable conditions for mass culture of C. calcitrans and produced concentrated diatoms in paste form that is readily available for aquaculture hatcheries at a lower cost. 相似文献
77.
78.
UV curing of perfluoro-alkyl-polyacrylate resins able to impart water as well as oil-repellency to cotton fabrics was studied
in comparison with conventional thermal polymerization. The process was assessed through weight gain and gel content measurements
while the properties conferred to cotton fabrics were determined in terms of water and oil contact angles, moisture adsorption,
and water vapor permeability. The polymerization yields were of the same order (>80 %) of those obtained with thermal curing
as well as the high contact angles with water (>127°) and oil (>118°) even at low resin add-on (3 %). UV cured resins yielded
oil contact angles mostly higher than 120° denoting super oil-repellent surfaces. Moreover the water and oil-repellency was
adequately maintained after washing. The moisture adsorption of finished fabrics was lower than that of untreated cotton,
but slightly higher for UV cured than thermally treated fabrics. Water vapor transmission rate showed that the finish treatment,
thermal as well as by UV curing, does not reduce the breathability of the original cotton. DSC analysis demonstrated that
the fiber pyrolysis is affected by the polymer add-on, while FTIR-ATR spectra of all finished fabrics showed typical peaks
of ester and C-F groups. XPS analysis showed small differences between thermal and UV curing coatings with each resin, while
coatings with the lowest percentage of fluorine groups did not affect the water and oil-repellency. 相似文献
79.
José Zilton Lopes Santos Bruno Fernando Faria Pereira José Augusto Figueira da Silva Carlos Alberto Franco Tucci Sílvio Vieira da Silva Tainah Manuela Benlolo Barbosa 《Communications in Soil Science and Plant Analysis》2017,48(11):1280-1290
We evaluated the effects of macronutrient and micronutrient omission, and of liming, on Jatropha curcas (JC) in greenhouse study. The experimental design was a factorial combination of 2 liming treatments (nil or 4.5 t. ha?1 of dolomitic lime) x 7 combinations of fertility status, with five replications. The concentrations and uptake of nutrients by JC plants follow the order: nitrogen > potassium > calcium ≥ Magnesium > sulfur > phosphorus > iron > boron > manganese > zinc > copper (N > K > Ca ≥ Mg > S > P > Fe > B > Mn > Zn > Cu), but the growth of JC plants was negatively affected mainly by omission of macronutrients, in the following order: P > N = K = S, on limed soil. Phosphorus is the most critical element for development. JC is responsive to micronutrients only when applied together with macronutrients. Potassium chloride is not recommended as K+ source for JC crop. Lime is recommended to improve growth and nutritional status of JC plants. 相似文献
80.
Ernestina Galdeano Fabiana Aída Guzmán Franco Fernández Luis Rogelio Conci 《European journal of plant pathology / European Foundation for Plant Pathology》2013,137(4):753-764
Twelve Argentinean 16SrIII (X-disease)-group phytoplasma strains were analyzed. Ten of them, detected in daisy (Bellis perennis), garlic (Allium sativum), ‘lagaña de perro’ (Caesalpinia gilliesii), periwinkle (Catharanthus roseus), ‘rama negra’ (Conyza bonariensis), ‘romerillo’ (Heterothalamus alienus), summer squash (Cucurbita maxima var. zapallito) and tomato (Solanum lycopersicum), are new phytoplasma strains while two strains, detected in garlic and China tree (Melia azedarach), have been previously described. The plants showed typical symptoms of phytoplasma diseases, such as leaf size reduction, proliferation, stunting and virescence. The identification and genetic diversity analysis of the phytoplasmas were performed based on 16S rDNA and ribosomal protein gene sequences. The classification into 16Sr groups and subgroups was established by actual and virtual RFLP analysis of the PCR products (R16F2/R16R2) compared with reference strains. According to the classification scheme, strains HetLL and ConWB-A and B represent two new subgroups 16SrIII-W and X, respectively. On the other hand, strains CatLL, TomLL and CaesLL are related to subgroup 16SrIII-B, and strains BellVir, TomRed, CucVir and GDIII-207 are related to subgroup 16SrIII-J. Ribosomal protein genes were amplified using primers rpF1/rpR1 and rpIIIF1/rpIIIR1. RFLP analysis performed with AluI, DraI and Tru1I (MseI isoschizomer) distinguished three new rp profiles within subgroup 16SrIII-B, one for subgroup 16SrIII-J, and one shared with strains of the new subgroups 16SrIII-W and X. The phylogenetic analysis based on 16S rDNA and ribosomal protein gene sequences confirmed the separation of HetLL and ConWB strains in two new subgroups and the close relatedness among subgroup J phytoplasmas, which have been detected only in South America. 相似文献