全文获取类型
收费全文 | 272篇 |
免费 | 9篇 |
国内免费 | 2篇 |
专业分类
林业 | 23篇 |
农学 | 6篇 |
45篇 | |
综合类 | 17篇 |
农作物 | 9篇 |
水产渔业 | 53篇 |
畜牧兽医 | 103篇 |
园艺 | 5篇 |
植物保护 | 22篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 13篇 |
2020年 | 6篇 |
2019年 | 2篇 |
2018年 | 8篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 5篇 |
2013年 | 37篇 |
2012年 | 6篇 |
2011年 | 11篇 |
2010年 | 14篇 |
2009年 | 8篇 |
2008年 | 14篇 |
2007年 | 22篇 |
2006年 | 12篇 |
2005年 | 14篇 |
2004年 | 14篇 |
2003年 | 11篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 8篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有283条查询结果,搜索用时 15 毫秒
1.
2.
ABSTRACT: The reproductive traits and the monthly larval abundance of the mantis shrimp Oratosquilla oratoria were investigated in Tokyo Bay, Japan, in 2002. The goal of the study was to elucidate the cause of changes in the monthly pattern of larval abundance from the 1980s to the 1990s as these changes relate to variation in the stock size of the adult shrimp. Oogenesis was divided into 10 stages by histological observation. The developmental stage of oocytes in an individual's ovary was synchronous, suggesting that almost all the oocytes in an ovary are spawned at the same time. The size at first maturity was estimated to be 7 ≤ body length ( BL ) < 8 cm. Fecundity was expressed as a function of BL , ranging from 19 300 eggs for 8 cm BL to 92 100 eggs for 14 cm BL . Small female shrimps (<10 cm BL ) spawned around August. Most large female shrimps (≥10 cm BL ) spawned around May, and some large female shrimps also spawned until September. Although most large female shrimps spawned in spring, the larval abundance was low before July and high from August onwards. The results suggest that a substantial decrease in the stock size of large individuals causes the low larval abundance before July. 相似文献
3.
4.
Yuzo Kurokawa Miki Okita Hirokazu Kubota Yoshimasa Tsumiyama Ichiro Chikamatsu Akiyoshi Tanaka Taketo Obitsu Kensuke Kawamura 《Animal Science Journal》2021,92(1):e13591
Farm managers' decision to cull dairy cows is based on the cows' milk production, history of disorder(s), and reproductive performance, each of which affects dairy cows' lifetime (herd life and productive lifespan). We investigated the relationships among the incidence of clinical mastitis (CM), the reproductive performance, and the culling rate. We also assessed the effects of these relationships on the lifetimes of dairy cows, using the records made before and after the introduction of an automatic milking system (AMS) at Hiroshima University Farm. Milk yield, CM incidence density, and culling rate of dairy cows increased after the AMS introduction. The CM incidence was associated with an elongation of the calving interval in cows with the same parity. CM in the 1st parity might have caused the reductions of the cows' lifetime and their parity at culling. A higher age at first calving (AFC) was associated with an increase in culling rate but did not lead to a significant decrease in lifetime. Investigations of the factors mediating CM in the 1st parity or AFC with CM incidence or culling rate in the later stages might contribute to the control of lifetime of dairy cows. 相似文献
5.
Shotaro NISHIMURA Hitomi SHIMODA Ichiro OSHIMA Yoshitaka ONO Kaoru OKANO Akira ISHIBASHI Shoji TABATA Hisao IWAMOTO 《Animal Science Journal》2005,76(6):575-579
Alpha‐melanocyte stimulating hormone (α‐MSH) is one of the main regulators for melanocytes, and the adenohypophysis is one of the major tissues for the synthesis of this hormone. The Silky fowl is a characteristic breed of chicken with hyperpigmentation throughout the body. The involvement of the adenohypophysis in the hyperpigmentation of this breed is not known. In the present study, the proportion of melanocyte stimulating hormone‐immunopositive cells (MSH cells) in the adenohypophysis was immunocytochemically compared between Silky, Red Cornish × New Hampshire (RN) crossbred and Japanese bantam cockerels at 15 weeks of age. After the body and gland were weighed, the adenohypophyseal cells were enzymatically dispersed and immunostained for α‐MSH, and the immunopositive MSH cells were counted. The weights of the body and adenohypophysis were heaviest in the RN crossbred, followed by the Silky and lightest in the bantam cockerels. In contrast, the ratio between adenohypophysis and bodyweight was much larger in the Silky and the bantam than in the RN crossbreed (P < 0.05). The population of MSH cells in the adenohypophysis was larger in the Silky (14.3%) than in the RN crossbreed (8.0%) and the bantam (8.1%) cockerels (P < 0.05). From these results, it was concluded that prepubertal Silky cockerel have numerous MSH cells in the adenohypophysis suggesting a relationship to hyperpigmentation. 相似文献
6.
The effects of concurrent cage contamination with Salmonella typhimurium and Eimeria tenella on the establishment of salmonella infection in day-old chickens were investigated. Chickens were divided into five groups: uninfected recipient birds placed in a cage contaminated by donor birds infected with E. tenella and S. typhimurium; E. tenella-infected recipients placed in a cage contaminated by S. typhimurium-infected donors; uninfected recipients placed in a cage contaminated by S. typhimurium-infected donors; E. tenella-infected recipients placed in a cage contaminated by uninfected donors; and uninfected recipients placed in a cage contaminated by uninfected donors. Three identical trials were conducted. Recipient birds were necropsied 4, 7, and 11 days after caging. In the cage where donor birds infected with both organisms had been reared, S. typhimurium counts in feces and number of feces positive for S. typhimurium were significantly (P less than 0.05) greater than those in the other cages on days 0, 4, and 7 after caging. Moreover, in this cage, more chicks died, counts of S. typhimurium in cecal contents were greater, and more birds were positive for S. typhimurium than in the other groups. This suggests that S. typhimurium infection in day-old chickens is enhanced in cages contaminated with E. tenella and S. typhimurium compared with infection in cages contaminated with S. typhimurium alone. 相似文献
7.
8.
Ishihara C Zamoto A Tsuji M Wei Q Azuma I Hioki K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(8):831-837
The erythrocyte-exchanged chimera mouse model has become to be a significant tool for studying animal and human (hu) protozoan haemoparasites, though the usefulness of this model varies depending primarily on the acceptability of xenogeneic red blood cells (RBC). To find a superior recipient in comparison with C.B-17/Jcl mouse with severe combined immuno-deficiency (scid) mutation, we examined in this report the non-obese diabetes (NOD)/shi-scid mouse, a recently available strain of SCID. When 2.5 x 10(8) of fluorescent dye-labeled hu-RBCs were transfused, C.B-17scid mouse eliminated them logarithmically by a simple linear regression, while NOD-scid mouse eradicated hu-RBCs by a unique two-step fashion, i.e., a potent but only briefly functioning RBC eradication followed by a weak steadily functioning step. The means of regression line constance +/- their standard deviations (SD) of 205 C.B-17scid and of 213 NOD-scid mice for their short- and long-lasting steps were -0.73 +/- 0.63, -0.53 +/- 0.25 and -0.16 +/- 0.10, respectively. Hu-RBC half-lives determined from these means of C.B-17scid mice and of NOD-scid mice for the short- and long-living steps were 3.6, 4.9 and 16.3 hr, respectively. Higher hu-RBC acceptability of NOD-scid mouse, especially at their long-lasting step, was also demonstrated under at an activated state of mouse innate immunity. Treatment with 1.0 mg heat-killed Candida cells caused an acceleration of hu-RBC elimination in both mouse strains but the magnitudes for the short- and long-living steps of NOD-scid mice evaluated by "stimulation index" were only 1/2.6 and 1/7.6 of C.B-17scid mice, respectively. 相似文献
9.
10.
This study is part of an effort to improve the quality of dried shiitake mushrooms (Lentinula edodes) in accordance with consumer preference. Results are presented of a trend survey that examined the preferences of consumers
using questionnaires combined with sensory evaluation. From the original preference (OP) survey, the distributions of OP divided
by age class (AC) were statistically equal to the results obtained in 2000. The medians of OP for teenagers and twenties were
“neutral” and “slightly like,” respectively. A firm preference change occurred between teenagers and those in their twenties.
It is empirically realized that sensory intensity (SI) scores that were too high or too low led to a low hedonic preference
(HP) score. The same tendency was seen for “neutralists” and “likers.” In addition, almost all distributions concerned with
HP had no significant difference between 2000 and 2005; for example, that of SI divided by AC. These results showed that the
preference for dried shiitake mushroom has been unaffected by the passage of the past 5 years. Dried shiitake mushrooms have
been used from ancient times and for many dishes; therefore, the overall preference appears to have remained unchanged. 相似文献