全文获取类型
收费全文 | 2613篇 |
免费 | 170篇 |
国内免费 | 2篇 |
专业分类
林业 | 271篇 |
农学 | 144篇 |
基础科学 | 28篇 |
760篇 | |
综合类 | 96篇 |
农作物 | 152篇 |
水产渔业 | 246篇 |
畜牧兽医 | 788篇 |
园艺 | 41篇 |
植物保护 | 259篇 |
出版年
2024年 | 5篇 |
2023年 | 48篇 |
2022年 | 43篇 |
2021年 | 84篇 |
2020年 | 93篇 |
2019年 | 47篇 |
2018年 | 142篇 |
2017年 | 148篇 |
2016年 | 134篇 |
2015年 | 106篇 |
2014年 | 123篇 |
2013年 | 188篇 |
2012年 | 234篇 |
2011年 | 224篇 |
2010年 | 118篇 |
2009年 | 79篇 |
2008年 | 170篇 |
2007年 | 170篇 |
2006年 | 134篇 |
2005年 | 125篇 |
2004年 | 98篇 |
2003年 | 104篇 |
2002年 | 73篇 |
2001年 | 20篇 |
2000年 | 10篇 |
1999年 | 7篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1974年 | 3篇 |
1958年 | 1篇 |
1954年 | 1篇 |
1944年 | 1篇 |
1940年 | 1篇 |
1938年 | 1篇 |
1934年 | 2篇 |
1911年 | 1篇 |
排序方式: 共有2785条查询结果,搜索用时 15 毫秒
941.
Tatiane Teles Albernaz Rômulo Cerqueira Leite Jenner Karlison Pimenta Reis Ana Paula de Sousa Rodrigues Telissa da Cunha Kassar Claudia Fideles Resende Cairo Henrique Sousa de Oliveira Rafaela das Mercês Silva Felipe Masiero Salvarani José Diomedes Barbosa 《Tropical animal health and production》2015,47(8):1625-1628
942.
María Luisa Rubio Teso Elena Torres Lamas Mauricio Parra-Quijano Lucía de la Rosa Juan Fajardo José M. Iriondo 《Genetic Resources and Crop Evolution》2018,65(4):1237-1253
Crop wild relatives (CWR) have recently received significant attention due to their value as plant genetic resources and their contribution to world food security. We present a prioritized checklist of CWR in Spain in which the criteria of crossability with crops of economic importance, endemicity and threat status have been taken into account. First, we selected a list of genera corresponding to the most relevant crops for Spain and at the international level. These crops were classified into use categories (Food, Forage & Fodder, Ornamental, and Industrial & Other uses) depending on their main use. The wild plant species native to Spain belonging to these genera were then listed. After evaluation by national experts in plant breeding, the resulting checklist contained 929 species. Further selection based on crossability, endemicity and threat status led to the generation of the Prioritized Spanish Checklist of crop wild relatives containing 578 species. Thirty-two percent of these species belong to the Forage & Fodder use category, 28% to the Ornamental category, 24% to the Food category and 16% to the Industrial & Other uses category. Thirty-five percent of the prioritized species are endemic to Spain, and over one-fourth are classified under some category of threat according to the International Union for Conservation of Nature. Endemicity and threat status rates in the Prioritized Spanish Checklist of CWR were higher than those found in the prioritized CWR inventories of other countries. A ex situ assessment reporting number of accessions showed that 70% of the prioritized Spanish CWR have accessions preserved in genebanks. 相似文献
943.
José Francisco Nieto-Cabrales Beatriz Salceda-Sánchez Héctor M. Zazueta-Islas Marlene Solís-Cortés Magaly Guadalupe Landa-Flores Juan Carlos del Mazo-López Laura Valtierra-Alzaga Juan J. Soto-Gutiérrez Heron Huerta-Jimenez Ingeborg Becker Jorge J. Rodríguez-Rojas Sokani Sánchez-Montes 《Zoonoses and public health》2024,71(2):217-224
944.
Belinda Vargas-Guerrero Pedro M. García-López Alma L. Martínez-Ayala José A. Domínguez-Rosales Carmen M. Gurrola-Díaz 《Plant foods for human nutrition (Dordrecht, Netherlands)》2014,69(3):241-247
Several studies support the health-promoting benefits of lupins, particularly lupin proteins. It has been demonstrated that Lupinus albus gamma conglutin (Cγ) protein lowered blood glucose levels; thus, Cγ showed promise as a new anti-diabetic compound for type 2 diabetes (T2D) treatment. The aim of this study was to evaluate the effect of Cγ on Ins-1 gene expression and on pancreatic insulin content in streptozotocin-mediated diabetic rats. Cγ was isolated from Lupinus albus seeds. Its identification was confirmed with polyacrylamide gel electrophoresis under native and denaturing conditions. We used streptozotocin (STZ) to induce T2D on the 5th day of life of newborn male Wistar rats (n5-STZ). After 20 weeks post-induction, these animals (glycemia?>?200 mg/dL) were randomly assigned to three groups that received the following one-week treatments: vehicle, 0.90 %?w/v NaCl (n5 STZ-Ctrl); glibenclamide, 10 mg/kg (n5 STZ-Glib); or Cγ, 120 mg/kg (n5 STZ-Cγ). Glucose and insulin levels were measured before and after treatment. Ins-1 gene expression was quantified using real time polymerase chain reaction and the pancreatic insulin content was evaluated with immunohistochemistry. Post-treatment, the n5 STZ-Cγ and n5 STZ-Glib groups showed reductions in glucose, increments in serum insulin, and increases in Ins-1 gene expression and beta cell insulin content compared to the n5 STZ-Ctrl group. The results showed that Cγ had beneficial effects on Ins-1 gene expression and pancreatic insulin content. These biological effects of Cγ strengthen its promising potential as a nutraceutical and/or new agent for controlling hyperglycemia. 相似文献
945.
Paula Pereira Torga Patr��cia Guimar?es Santos Melo Helton Santos Pereira Luis Cl��udio de Faria Maria Jos�� Del Peloso Leonardo Cunha Melo 《Euphytica》2013,189(2):239-248
The objectives of this study were to assess which environmental factors (local, season or years) are the most important to contribute for the interactions with genotypes of common black beans and to verify the existence of genotypes with broad and/or specific adaptation to the diverse planting seasons in Central Brazil. Data of grain yields for 13 genotypes in 18 field trials used for cultivar registration were utilized, across 2?years (2003 and 2004). Analyses of variance were carried out with decomposition of the genotype x environment interactions. Firstly, data of 18 trials were used, allowing a partial isolation of factors and, subsequently, eight trials were used to allow a complete isolation of the factors. The genotype x sowing seasons (R2?=?4.2?%) and genotype x year (R2?=?4.1?%) interactions were of the greatest important, while genotype x location was less important (R2?=?3.0?%). It was concluded that is more important to conduct evaluations of genotypes in different seasons and years rather than in different locations. The majority of the genotypes tested presented specific adaptation, although it was possible to identify superior lines with wide adaptation. 相似文献
946.
Patrícia F. Lito José P. S. Aniceto Carlos M. Silva 《Water, air, and soil pollution》2012,223(9):6133-6155
The presence of some anionic species, such as nitrate, nitrite, chloride, sulfide, fluoride, and cyanide, in water supplies may represent a serious environmental problem. In this work, the main sources and harmful effects of their bioaccumulation on living organisms are reviewed, as well as the most adopted technologies for their uptake. The major advantages and disadvantages of each methodology are also listed. In general, ion-exchange has been elucidated as the most suitable removal process. In view of that the most promising materials used to remove anionic pollutants from aqueous solutions are highlighted in this review. In particular, the major efforts towards the development of low-cost and easily available effective sorbents for water decontamination are covered. For instance, natural waste solid materials and derivatives have emerged as promising low-cost exchangers for selective anions uptake. Besides, a number of structural modifications including the introduction of more suitable surface functional groups or compensation species into the sorbent matrix have been investigated in order to enhance sorbents selectivity and capacity for anionic pollutants. The influence of speciation and removal conditions is also focused. 相似文献
947.
948.
Changes in land use in the Orinoco lowlands affect the daily trends of energy and water vapor fluxes. We analyzed these fluxes along a disturbance gradient beginning from a cultivated tall-grass Andropogon field (S1) and extending over three savanna sites with increasing woody cover over herbaceous vegetation. The savanna sites encompass a herbaceous savanna (S2), a tree savanna (S3) and a woodland savanna (S4). In the wet season, there were differences in the radiation budget: seasonally averaged albedo for S1 (0.17) exceeded that of S2-S4 (0.13-0.14). Eddy covariance fluxes indicate that the partitioning of the daily net radiation (Rn) into sensible and latent heat (lambda E) fluxes depends on land use. During the wet season, evapotranspiration (i.e., lambda E) over the S1-S4 sites accounted for a variable fraction of Rn (i.e., 0.75, 0.52, 0.67 and 0.68, respectively). Therefore, the Bowen ratio was typically below 1. As the dry season progressed, the lambda E/Rn ratio decreased markedly with increasing air and canopy temperatures and air humidity mole fraction deficit. The maximum evaporation rate over the S1-S4 sites was 3.2, 2.5, 3.5 and 4.1 mm day(-1), respectively, and the annual values were 721, 538, 771 and 732 mm year(-1), respectively, equivalent to 49, 65, 52 and 88% of the rainfall. Soil water content fell from a maximum above 0.28 in the wet season to 0.030, 0.026, 0.030 and 0.028 m(3) m(-3) at sites S1-S4, respectively, in the dry season. Leaf area index was greatly reduced as herbaceous vegetation dried out. 相似文献
949.
Maria João Gaspar José Luís Louzada Alexandre Aguiar Maria Helena Almeida 《Annals of Forest Science》2008,65(7):703-703
- ? It is essential to understand how characteristics are related to each other in breeding programmes to select wood properties, in order to avoid that, in selecting for one trait, we are negatively affecting another. Moreover, measuring wood properties is time consuming and expensive.
- ? This study assesses genetic and phenotypic correlations between wood density components and spiral grain of 46 half-sib families of Pinus pinaster in seventeen-year-old trees.
- ? Results showed that genetic correlations for all wood density components were higher than corresponding phenotypic correlations. Furthermore, all wood density components were highly genetically correlated with ring density, and also closely associated among themselves. Results showed a higher genetic correlation of ring density with earlywood density (r g = 0.96) than with latewood density r g = 0.79). A moderate to high positive genetic correlation was found between spiral grain and wood density characteristics (0.29–0.61).
- ? We conclude that ring density (overall wood density) can be improved by increasing either earlywood density, latewood percent, or both of these traits, and spiral grain can be modify in future plantations.
950.
Uribeetxebarria Asier Martínez-Casasnovas José A. Escolà Alexandre Rosell-Polo Joan R. Arnó Jaume 《Precision Agriculture》2019,20(2):179-192
Precision Agriculture - Estimation of yield or other fruit quality parameter is of great interest to farmers to decide on management actions just before harvesting and, in any case, to anticipate... 相似文献