首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   273篇
  免费   3篇
  国内免费   1篇
林业   11篇
农学   6篇
基础科学   1篇
  13篇
综合类   11篇
农作物   11篇
水产渔业   42篇
畜牧兽医   153篇
植物保护   29篇
  2022年   4篇
  2021年   16篇
  2020年   1篇
  2019年   2篇
  2017年   2篇
  2016年   3篇
  2015年   14篇
  2014年   19篇
  2013年   14篇
  2012年   8篇
  2011年   22篇
  2010年   5篇
  2009年   17篇
  2008年   25篇
  2007年   21篇
  2006年   15篇
  2005年   13篇
  2004年   18篇
  2003年   19篇
  2002年   19篇
  2001年   4篇
  2000年   9篇
  1999年   2篇
  1996年   1篇
  1993年   1篇
  1991年   1篇
  1990年   1篇
  1959年   1篇
排序方式: 共有277条查询结果,搜索用时 31 毫秒
121.
The aim of the present study was to clarify the ovarian and hormonal dynamics after the aspiration of follicular fluid in cows with follicular cysts. Follicular fluid was aspirated from the follicular cysts and follicles that were fated to become cystic follicles and other coexisting normal follicles, respectively, in lactating cows (n = 3). After the aspiration procedure, new follicles developed and reached a diameter of 25 mm without ovulation within 13–19 days. The plasma concentrations of inhibin decreased and follicle-stimulating hormone increased rapidly after the aspiration procedure, and subsequently increased and decreased, respectively, as a new follicle grew. No luteal structures developed after the aspiration procedure, and the animals’ plasma progesterone levels remained low. The present study indicates that the cystic follicles are never luteinized by the aspiration of follicular fluid, and consequently, new follicular cysts are observed to repeatedly develop.  相似文献   
122.
A 5-year-old female cat with nonregenerative anemia and thrombocytopenia was diagnosed with myelodysplastic syndromes (MDS), since peripheral blood and bone marrow (BM) examination revealed various dysplasias and a blast ratio of 19%. Chemotherapy with azacytidine (AZA; 70–35 mg/m2, 3–5 days, three cycles) and treatment with prednisolone, antibiotics, and vitamin K2, and blood transfusion were performed. On day 106, blast cells and dysplasia had decreased in the BM, and the cat remained alive for at least 1,474 days. This report is the first on feline MDS treated with AZA, suggesting appropriate drug dosage, interval and effective combination should be investigated and the pharmacological and cell biological mechanisms needs to be elucidated in the future.  相似文献   
123.
We investigated the effect of heat stress on Ca, P and Mg balance and bone turnover in lactating cows. In a 2 × 2 crossover design, four multiparous lactating Holstein cows were kept in a chamber and subjected to a constant moderate (18°C) ambient temperature (MT) or high (28°C) ambient temperature (HT). The cows were fed total mixed ration (Ca, 0.7%; P, 0.4%; Mg, 0.2%) ad libitum. The milk yield under HT (35.4 kg/day) tended to be lower (P < 0.10) than that under MT (43.2 kg/day). The concentrations of milk P (P < 0.05) and Mg (P < 0.01) were significantly lower under HT than MT. The Ca, P and Mg intake (P < 0.10); Ca (P < 0.10), P, and Mg (P < 0.05) secretion into milk; and Ca (P < 0.05), P (P < 0.01), and Mg (P < 0.05) absorption in the intestine were lower under HT than MT. The plasma osteocalcin, a marker of bone turnover, was significantly lower (P < 0.05) under HT than MT. Heat stress did not affect plasma C‐telopeptide of collagen type I, a bone resorption marker, and plasma parathyroid hormone concentration.  相似文献   
124.
REIJI  MASUDA  JUN  SHOJI  MITSUHIRO  AOYAMA  MASARU  TANAKA 《Fisheries Science》2002,68(2):320-324
ABSTRACT: Developmental changes of swimming speed were analysed in the chub mackerel Scomber japonicus raised on two distinct dietary regimens. One group was fed only zooplankton such as rotifers and Artemia nauplii (R group) and the other group was fed rotifers plus red sea bream Pagrus major larvae (Pm group). Fish from the Pm group grew faster than those from the R group, and both the cruise and burst swimming speeds were faster for the Pm group even when match-sized comparisons were made. Fish in the Pm group attained a standard length (SL) of 17.5 mm by day 14 and their cruise and burst swimming speeds were 5.39 SL/s and 18.45 SL/s, whereas the R group attained 17.35 mm SL by day 17 and their cruise and burst swimming speeds were 4.28 SL/s and 13.98 SL/s. The results suggest that the swimming speed of chub mackerel in the wild would develop differently depending on the food resources they happen to encounter.  相似文献   
125.
Oxidative stress markers, ascorbic acid, and sulfhydryl (SH) residue concentration in primiparous cows' plasma and their relationship to milking performance during hot seasons were investigated. The rectal temperature of cows correlated negatively with SH residue (r = −0.38, n  = 38, P  < 0.05) and ascorbic acid (r = −0.34, P  < 0.05) concentrations in the cows' plasma. The group with a higher concentration of ascorbic acid over the mean value produced significantly more milk ( P  < 0.05) than did the group with a lower ascorbic acid concentration. Although the cows' milk production showed a positive correlation with ascorbic acid concentration in plasma (r = 0.47, P  < 0.05), the relation of SH residue concentration to milk yield was not constant. The plasma SH residue concentration during the hot season correlated positively with milk protein % (r = 0.38, P  < 0.05), lactose % (r = 0.35, P  < 0.05), and solid-non-fat (SNF) % (r = 0.47, P  < 0.05), respectively, but not with fat %. On the other hand, ascorbic acid concentration in plasma showed negative correlations with milk fat % (r = −0.34, P  < 0.05) and protein % (r = −0.49, P  < 0.05), but correlated positively with lactose % (r = 0.52, P  < 0.05). The produced amount (g/day) of milk protein (r = 0.42, P  < 0.05), lactose (r = 0.61, P  < 0.05), and SNF (r = 0.56, P  < 0.05) showed positive correlations with ascorbic acid concentration in plasma.  相似文献   
126.
The objective of this study was to investigate transportation conditions and behavioral and physiological responses of beef steers to long distance commercial transport throughout the year Japan. Japanese Black × Holstein steers (7.9 ± 0.6 months of age; 320.0 ± 19.0 kg) were transported by truck in spring (n = 8), summer (n = 5), autumn (n = 8) and winter (n = 5). Transport distances (time) were 1020.6 km (25 h including lairage periods): 615.4 km (6.4 h) on expressways, 163.2 km (3.7 h) on arterial roads and 242.0 km (10.5 h) by ferry. The space allowance of the truck was about 1.6 m2/head in all seasons. Internal temperatures of the truck were 14.7 ± 4.7°C in spring, 27.9 ± 2.6°C in summer, 24.4 ± 2.8°C in autumn and 9.2 ± 4.3°C in winter. Although internal noise and airflow velocity of the truck were louder and greater while moving on expressways (101.1 ± 8.3 dB and 1.50 ± 1.50 m/s) than on arterial roads (92.0 ± 15.2 dB and 1.32 ± 1.41 m/s) (both P < 0.05), more steers lay down while moving on expressways (P < 0.001). Blood glucose, plasma cortisol, and serum triiodothyronine (T3) concentrations and ALT activity were higher in spring (all P < 0.05). This could be explained by that vibration acceleration (m/s2) of the truck in the longitudinal direction was greater in spring (?0.19 ± 0.43) than in the other seasons (?0.14 ± 0.09 in summer, ?0.15 ± 0.20 in autumn and ?0.15 ± 0.13 in winter) (all P < 0.05). Heart rate, serum concentrations of T3, total cholesterol, total protein, and AST and ALT activities were higher just after transport than 1 week after transport (all P < 0.05). However, transport stress should be not severe, since no difference between before and after transport was shown on concentrations of plasma cortisol, blood lactate and serum NEFA, serum triglyceride and serum pH and liveweight.  相似文献   
127.
It is well known that the immune system changes with age during development and maturation in Holstein cattle. But age-related changes in leukocytes and T cell subsets in peripheral blood of Japanese Black cattle still remain unclear. The aim of the present study was to investigate comparative changes of leukocytes (granulocytes, monocytes, B cells and T cells) and T cell subsets (CD4+, CD8+, γδ, CD8+γδ and WC1+γδ T cells) in Japanese Black cattle aged 0.5, 1, 2, 6, 18 and 36–41 (adult) months on flow cytometry using specific monoclonal antibodies for the cell surface markers. T cell proportion was approximately 40% in 2-month-old cattle and decreased to 20.6% in adults. In contrast, B cell proportion significantly increased from 7.4% to 28.2% with age. In T cell subsets the percentage of CD4+ T cells significantly increased from 40.5% to 60%, but that of WC1+γδ T cell subset significantly decreased with age. The percentages of CD8+ and CD8+γδ T cells did not change. The present study details the proportional changes in leukocyte and T cell subsets with age in the peripheral blood of Japanese Black cattle and these findings are similar to those described for Holstein cattle.  相似文献   
128.
采用培养箱内增加CO2浓度的方法,在塑膜·岩棉(CP·RW)培养方式下对大花蕙兰(Cymbidium)试管苗进行培养.结果表明,在CO2施用条件下的大花蕙兰试管苗,其形态指标、叶绿素指数和叶片气孔密度均高于无CO2施用处理.采用SSR法进行比较(显著水平P≤0.05),其中在株高、叶长、叶幅、根数、最长根长、鲜重、干物重和气孔密度等重要指标之间存在显著性差异.  相似文献   
129.
探讨了采用RAPD 分子标记法进行茶树及其近缘种分类和亲缘关系鉴别的可能性。结果表明, RAPD 能有效地区分物种间和茶树种内变种间的差异, 阿萨姆类型茶树和中国类型茶树的特异性RAPD 分子标记分别为1 200 bp 的WKA-24 a 和610 bp 的WKA-24 b 。日本茶树品种与中国茶树品种具有较近的亲缘关系。部分越南茶树品种为中-印杂种。图1 表1 参4  相似文献   
130.
In order to elucidate the relationship between migration period and immunity related to susceptibility, we conducted research on Black-headed gulls (Chroicocephalus ridibundus). We captured 260 gulls and collected their peripheral blood. Their leukocyte (WBC) count, percentages of heterophils (Het) and lymphocytes (Lym), heterophil and lymphocyte ratio (H/L ratio), and CD4 and CD8α expression levels (CD4 and CD8α, respectively) were quantitatively analyzed over three migration periods (Autumn migration, Wintering, Spring migration). In Adult gulls, WBC counts and CD4 levels significantly increased. Moreover, the Het and H/L ratio decreased from the Autumn migration to Wintering. Conversely, only WBC counts and CD4 levels measurements significantly decreased from Wintering to Spring migration (P<0.05). The tested parameters of the Tokyo-bay population show a greater significant difference than the measurements of immunity of the Mikawa-bay population. This study suggests that the migratory period has a negative effect on an aspect of the immune system. Including the period-difference in the immune systems in the local population, it is necessary to investigate the relationship between the ecology of migratory birds and their immunity.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号