全文获取类型
收费全文 | 299篇 |
免费 | 20篇 |
专业分类
林业 | 37篇 |
农学 | 3篇 |
48篇 | |
综合类 | 18篇 |
农作物 | 12篇 |
水产渔业 | 47篇 |
畜牧兽医 | 137篇 |
园艺 | 4篇 |
植物保护 | 13篇 |
出版年
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 10篇 |
2019年 | 6篇 |
2018年 | 13篇 |
2017年 | 9篇 |
2016年 | 8篇 |
2015年 | 10篇 |
2014年 | 7篇 |
2013年 | 19篇 |
2012年 | 9篇 |
2011年 | 18篇 |
2010年 | 11篇 |
2009年 | 4篇 |
2008年 | 17篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2005年 | 15篇 |
2004年 | 9篇 |
2003年 | 5篇 |
2002年 | 9篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1992年 | 4篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1974年 | 3篇 |
1973年 | 6篇 |
1948年 | 1篇 |
1947年 | 4篇 |
1946年 | 5篇 |
1945年 | 2篇 |
1944年 | 1篇 |
1942年 | 3篇 |
1941年 | 3篇 |
1940年 | 1篇 |
1939年 | 9篇 |
1938年 | 9篇 |
1937年 | 7篇 |
1936年 | 2篇 |
1935年 | 1篇 |
1933年 | 2篇 |
1932年 | 1篇 |
1931年 | 2篇 |
1930年 | 1篇 |
1928年 | 1篇 |
1924年 | 3篇 |
1923年 | 1篇 |
排序方式: 共有319条查询结果,搜索用时 15 毫秒
1.
Effect of Stocking Density on Growth,Survival, and Condition of the Mexican Cichlid Cichlasoma beani
Edgar A. Aragon‐Flores Edna F. Valdez‐Hernandez Leonardo Martinez‐Cardenas Maria R. Castaeda‐Chavez Alfonso A. Gonzales‐Diaz Miriam Soria‐Barreto Javier M. J. Ruiz‐Velazco Emilio Pea‐Messina 《Journal of the World Aquaculture Society》2014,45(4):447-453
The Mexican cichlid Cichlasoma beani is currently exploited regionally as food and can be commercialized in the aquarium trade. Natural populations of C. beani may already be negatively affected by anthropogenic alteration of the areas in which it is distributed. The aim of the present study was to examine the effect on growth, survival, and condition of C. beani cultured in three stocking densities: three (D3), six (D6), and nine (D9) fish per each 40 L tank. At the end of a 6‐wk trial the fish cultured in D3 were longer, heavier, and grew faster than the rest of the treatments but their survival was the lowest compared to D6 and D9. The mortalities were caused by a strong aggressive behavior in D3. 相似文献
2.
Edgar G. GUTIÉRREZ Isabela VIVAS-TORO Daniela CARMONA-RUÍZ David VILLALOBOS-CHAVES Bernal RODRÍGUEZ-HERRERA Melina Del REAL-MONROY Gloria LEÓN-AVILA Jorge ORTEGA 《Integrative zoology》2021,16(5):646-658
Ectophylla alba is a tent-making bat that roosts in mixed-sex clusters comprising adults and offspring. Our goal was to determine the genetic identity of individuals belonging to different roosting groups. We tested the hypothesis of kin selection as a major force structuring group composition. We used 9 microsatellites designed for E. alba to determine the genetic identity and probability of parentage of individuals. We analyzed parentage and kinship using the software ML-Relate, GenAIEx, and Cervus. The obtained relationship probabilities (0.5) revealed a clear maternal relationship between female adults and offspring with allele compatibility, and at least 5 relationships between male adults and pups. We found a low degree of relatedness within roosting groups. Between roosting groups at different sites, the mean probability of a half-sibling relationship ranged from 0.214 to 0.244 and, for full-sibling relationship, from 0.383 to 0.553. Genetically, adult individuals were poorly related within clusters, and kinship as an evolutionary force could not explain group membership. 相似文献
3.
Marcial Arellano‐Martínez Bertha Patricia Ceballos‐Vázquez César Ruíz‐Verdugo Edgar Pérez de León Rafael Cervantes‐Duarte Pedro Martin Domínguez‐Valdéz 《Aquaculture Research》2011,42(4):571-582
The lion's paw scallop, Nodipecten subnodosus (Sowerby) has considerable aquacultural potential due to its fast growth and large adductor muscle. Prior investigations throughout northwestern Mexico's littoral have reported highly variable growth rates; furthermore, no studies are available of the environment on growth and gametogenesis in this species under culture conditions. This investigation assesses the effect of food availability and temperature on the growth and gametogenesis of N. subnodosus in a suspended culture system at Guerrero Negro lagoon, Mexico. After 1 year of cultivation, N. subnodosus reached 69.13 mm in shell height (SH) (0.196 mm day?1, 14 months old). Two significant growth spurts were observed: over the two first months of culture (August and September 2001, mean growth rate 0.4 mm day?1) and in September 2002 (0.3 mm day?1), both related to high temperatures and chlorophyll a concentrations. The onset of gametogenesis occurred in April 2002, with an increase in temperature (10‐month‐old scallops, 54.5 mm SH). The first spawning occurred in October and November (86.2 and 93 mm SH), with peak temperatures. These results, together with the analysis of previous reports, indicate that N. subnodosus has a higher preference for temperate areas; therefore, the Guerrero Negro lagoon appears to be a suitable site to culture this species. 相似文献
4.
5.
G. Reinhold und Edgar Kransen 《Forstwissenschaftliches Centralblatt》1939,61(16):517-521
Ohne Zusammenfassung 相似文献
6.
7.
8.
Loreida Timberg Kadri Koppel Rain Kuldjärv Edgar Chambers IV Aussama Soontrunnarudrungsri Suntaree Suwonsichon 《Journal Of Aquatic Food Product Technology》2013,22(6):552-566
The aim of the study was to describe and evaluate competitiveness of Estonian spice-cured sprat products in Estonia and Thailand. Sample A was saltiest, Sample B had lowest overall spiciness, and Sample C had highest pepper flavor and sour taste intensity. The main drivers of consumer acceptance for the spice-cured sprat products were different: flavor and appearance in Estonia and appearance and odor in Thailand. In Estonia, one cluster of consumers liked the traditional (Sample A) and lightly spiced (Sample B) sprat products, while the other cluster liked the traditional (Sample A) and the marinated (Sample C) sprat products. In Thailand, all samples scored low, but manual clustering indicated that marinated (Sample C) sprat products are most acceptable. The current study showed that spice-cured sprat products in general can be accepted by Thai consumers, especially as part of meals, if further flavor development is carried out with the products. 相似文献
9.
Edgar C Amar Viswanath Kiron Shuichi Satoh Nobuaki Okamoto and Takeshi Watanabe 《Fisheries Science》2000,66(6):1068-1075
SUMMARY: We attempt to assess the impact of different levels of dietary β-carotene on immune function in rainbow trout. Semi-purified diets containing 0, 40, 200, and 400 mg β-carotene/kg dry diet were fed for 12 weeks to fish with average weight of 45 g. In addition to the humoral and cellular immune parameters, growth and feed utilization were examined. There were no marked differences in growth and feed utilization showing that β-carotene was not particularly efficient in enhancing growth of rainbow trout. Of the immune parameters measured, total immunoglobulin was significantly highest for the 200 mg β-carotene fed group. Serum complement activity (alternate pathway) at 200 and 400 mg β-carotene supplementation was significantly higher than that of the unsupplemented group. An increasing trend in lysozyme activity was observed, however, the differences among the groups were not significant. Phagocytic activity was similar among diet groups except at the highest level of supplementation where it was the maximum. Oxygen radical production by peripheral blood leukocytes appeared to be lower at higher levels of carotenoid supplementation. Overall, dietary β-carotene clearly enhanced immune response parameters in rainbow trout such as serum complement activity and total plasma immunoglobulin but did not show a definite influence for the other factors examined in the present study. 相似文献
10.
Maria Excelsis M. ORDEN Wilfred E. JAMANDRE Ernesto O. BROWN Edgar A. ORDEN Emilio M. CRUZ Ana Marie P. ALO Edwin C. VILLAR 《Animal Science Journal》2005,76(2):179-185
Preference for goat characteristics was determined from 42 traders in six markets in Pangasinan, an important trading center for goats in Luzon, the Philippines, and analyzed using a hedonic price model to determine whether these characteristics are important price determinants of goats. This information is important to goat raisers to respond to the needs of the local market, and thus to achieve a better price and higher income in goat raising. Meatiness, size, breed, sex and age (in descending order) were the dominant goat characteristics preferred by traders. Meatiness had the largest positive influence on price, with a price premium of US$6.24 (US$1.00 = PhP 53), whereas the age of the animal had the smallest influence at US$3.72. However, size and meatiness are manifestations of good breeds. Therefore, continued efforts to improve breeds in order to produce good quality goats are imperative to cater to market needs. Different characteristics implied different price premiums. Traders offered a higher price premium for better goat characteristics; thus, the improvement of these characteristics could result in higher returns for goat raisers. 相似文献