全文获取类型
收费全文 | 409篇 |
免费 | 28篇 |
国内免费 | 1篇 |
专业分类
林业 | 30篇 |
农学 | 16篇 |
基础科学 | 1篇 |
85篇 | |
综合类 | 19篇 |
农作物 | 19篇 |
水产渔业 | 39篇 |
畜牧兽医 | 211篇 |
园艺 | 3篇 |
植物保护 | 15篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 10篇 |
2019年 | 14篇 |
2018年 | 13篇 |
2017年 | 10篇 |
2016年 | 12篇 |
2015年 | 16篇 |
2014年 | 16篇 |
2013年 | 38篇 |
2012年 | 31篇 |
2011年 | 33篇 |
2010年 | 9篇 |
2009年 | 21篇 |
2008年 | 26篇 |
2007年 | 23篇 |
2006年 | 27篇 |
2005年 | 15篇 |
2004年 | 17篇 |
2003年 | 17篇 |
2002年 | 6篇 |
2001年 | 13篇 |
2000年 | 9篇 |
1999年 | 3篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 7篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有438条查询结果,搜索用时 17 毫秒
61.
Thanh Quang Dang‐Nguyen Hiep Thi Nguyen Tamas Somfai David Wells Nguyen Thi Men Nguyen Viet‐Linh Junko Noguchi Hiroyuki Kaneko Kazuhiro Kikuchi Takashi Nagai 《Animal Science Journal》2018,89(6):880-887
We investigated whether high‐quality in vitro matured (IVM) oocytes can be distinguished from poor ones based on the morphological changes after treatment with hyperosmotic medium containing 0.2 mol/L sucrose in pigs. We hypothesize that IVM oocytes maintaining round shape have higher quality than mis‐shapened oocytes following dehydration. Oocyte quality was verified by determining embryonic developmental competence using in vitro fertilization, nuclear transfer and parthenogenetic activation. In all cases, the round oocytes had greater (p < .05) developmental competence than that of mis‐shapened oocytes in terms of blastocyst rate and total cell number in blastocysts obtained after 6 days of in vitro culture. We also confirm that round aged oocytes are higher in quality than mis‐shapened aged oocytes. In an attempt to find out why high‐quality oocytes maintain a round shape whereas poorer oocytes become mis‐shapened following sucrose treatment, we examined the arrangement of actin microfilaments and microtubules. Abnormal organization of these cytoskeletal components was higher (p < .05) in mis‐shapened oocytes compared to round oocytes after 52 hr of IVM. In conclusion, sucrose treatment helps selection of high‐quality oocytes, including aged oocytes, in pigs. Abnormal cytoskeleton arrangements partly explain for low developmental competence of mis‐shapened oocytes. 相似文献
62.
Masanori Kasai Tsukasa Yamamoto Koichiro Kitasako Sadao Kiyohara 《Fisheries Science》2009,75(5):1125-1132
To examine the feeding activity characteristics of Japanese sea catfish Plotosus japonicus, access to feed box (feeding activity) and the number of food pellets consumed (food intake) were recorded under laboratory
conditions. When fed ad libitum under a 12:12 h light–dark (LD) cycle, all fish exhibited feeding activity and consumed food
during the dark period. Feeding activity increased in the presence of food, and this increased activity level continued for
several days after food removal. During restricted food availability within the light period of the LD cycle, seven of nine
fish exhibited food-anticipatory activity (FAA) both before and after the 12:00 food-restricted time. This FAA persisted under
constant light conditions (in nine of nine fish). The average circadian free-running period was 24 h. These results suggest
that P. japonicus exhibits a nocturnal feeding activity rhythm, which may be synchronized by a food-restricted time. 相似文献
63.
Tohru Kobata Müjde Koç Celaleddin Barutçular Ken-ichi Tanno Masanori Inagaki 《Plant Production Science》2018,21(2):71-82
Environmental and plant factors critical to the grain yields of bread (Triticum aestivum L.), durum (T. durum L.) and emmer (T. dicoccum L.) wheat cultivars were investigated at two Mediterranean rain-fed field sites: Adana in southeastern Turkey (2009 and 2010) and Aleppo in northern Syria (2009). The grain yield (GY) and biological yield (BY) of most cultivars were higher in Adana than in Aleppo, and the lower GY in Aleppo resulted from lower harvest index (HI) and lower BY due to higher temperatures and lower rainfall. The variations in the HI among cultivars were greater in Adana than in Aleppo. The GY was closely related to the HI but not the BY across cultivars at each site, and a higher GY was accompanied by a superior conversion-efficiency of incident radiation during the grain filling period for grain yield [GY/Ra, where Ra is the cumulative radiation for 30 days after heading (D30)] across all observations. The GY/Ra correlated negatively with the average temperature for D30, and higher HI values resulted in higher GY/Ra. In Adana, the time from anthesis to physiological-maturity decreased as the average temperature for D30 increased, resulting in a lower HI. Cultivars exhibiting the early heading trait can effectively escape the negative impacts of terminal high-temperature and water-shortage conditions on the HI. The results suggested that the HI is a critical factor for GY across diverse wheat cultivars under terminal high-temperatures and water-shortages in Mediterranean areas, and the BY is also an important factor under severe water-limitation conditions. 相似文献
64.
Pseurotins A1 (1) and A2 (2) were isolated from a culture broth of the fungal strain Aspergillus fumigatus WFZ-25 as stereoisomers of pseurotin A (3) in 2011. We also isolated 1 and 2 together with 3 from A. fumigatus OUPS-T106B-5 separated from the marine fish Mugil cephalus. In this study, we re-examined the stereochemistry of 1 and 2 using chemical transformation and the CD spectra, and found the relationship between the CD Cotton effect and the absolute configurations of 1 and 2, which led us to revise the stereostructure of pseurotin A2. 相似文献
65.
This paper summarizes the characteristics of regional-scale nitrogen (N) flow models. The regional scale is generally considered to be an area that ranges from more than 10 km2 to the size of a continent. Parameterization is the key process in creating a regional-scale model. During parameterization, transfer functions that reflect the controlling factors must be created at the target scale because the influence of different factors will change with the size of the scale. Watersheds are the most useful unit for evaluating overall N discharge; however, regional activity data is most often available for municipal units. Thus, municipal units must be reaggregated into watershed units. A longer time period is desirable to normalize seasonal and annual variations at regional scales. Parameters that influence N flow must match the investigated spatial and temporal scales. Given the need to use a range of parameters that vary in terms of the quality of the data, models exhibit inevitable uncertainties. Quantification of the uncertainties and verification of the estimated results are required. Error propagation, the Monte Carlo simulation method and maximum and minimum values have been used to obtain different threshold values of uncertainty. To verify regional-scale N flow models, the following five approaches have been used or proposed: (1) calibration of the model by detailed monitoring at multiple sites, (2) verification of the most important process of the extrapolation mechanisms, (3) verification of the N budget, paying particular attention to water quality, (4) comparison with the results quantified by different models, (5) comparison with aerial or satellite image analysis. As regional-scale modeling of N flow will become more important in the future, it is important to develop models than can accurately estimate N dynamics at this scale. 相似文献
66.
Suzette B. LINA Masanori OKAZAKI Dorothea Sonoko KIMURA Yoshiharu YANO Koyo YONEBAYASHI Masato IGURA Marcelo A. QUEVEDO Alan B. LORETO 《Soil Science and Plant Nutrition》2009,55(1):114-123
Previous trials have revealed variable responses of sago palm ( Metroxylon sagu Rottb.) to fertilizer application, particularly nitrogen (N). In the present study, we quantified the fertilizer use efficiency (FUE) of sago palm for the first time using 15 N-labeled fertilizer in pot and field experiments. The pot experiment was conducted in Japan using a 2:1 mixture of sand to Philippine soil. The field experiment was conducted in Leyte in the Philippines. Both experiments consisted of three replicates in each of three treatments: control, 15 N urea at 50 kg N ha−1 and 15 N urea at 100 kg N ha−1 . The N uptake of sago palm increased significantly, but inconsistently with increasing N application. The few instances of a significant increase in N uptake did not translate into significant improvements in growth parameters, except for the number of leaflets in the pot experiment. The FUE values for sago seedlings (< 6 months) in the pot experiment treated with 50 and 100 kg N ha−1 were 10.5 and 13.2%, respectively, whereas for the 2-year-old sago palms in the field, the corresponding FUE values were 14.8 and 12.0%. The FUE values were similar at the two levels of N application in both experiments. Sago growth parameters appeared to be insensitive to N application, suggesting that the form of N and the timing of N fertilization are important factors for sago palms. Therefore, the use of N fertilizer in sago production can only be justified after determining and fully understanding the response of sago palm to N application. 相似文献
67.
Masanori KOYAGO Ken NAKADA Nobuo TSUNODA Masaharu MORIYOSHI Yutaka SAWAMUKAI 《Journal of Equine Science》2009,20(1):1-5
To clarify the physiological changes of sperm morphology in active Thoroughbred stallions
during the breeding season, we examined the dismount semen collected from the penile
urethra immediately after service. The spermatozoa were analyzed for relationships between
the morphology and the stallion’s age or the number of services. Seasonal variation was
apparent in the rate of the sperm tail abnormalities, spermatozoa with cytoplasmic
droplets, appearance of medusa cells, and sperm head length. Area and width of the sperm
head correlated negatively with age (P<0.05). The rate of appearance of medusa cells
and the length of the sperm head were positively related to the number of services
(P<0.05), and the aspect ratio was negatively related (P<0.01). 相似文献
68.
Hiromi KEINO Atsushi FUNAHASHI Hiroomi KEINO Chihiro MIWA Masanori HOSOKAWA Yoshihiro HAYASHI Kenji KAWAKITA 《Journal of Equine Science》2009,20(4):79-88
In this study, we applied a novel psycho-educational horseback riding (PEHR) program to
the treatment of four Japanese children with pervasive developmental disorders (PDD) in
order to facilitate the acquisition of verbal and nonverbal communication skills. The
behavioral changes in each child were evaluated using a psychological and behavioral
scale. The scale for evaluating the effect of Human-Equips-Interaction on Mental activity
(HEIM scale) was designed to assess the behavioral improvement of children based on the
following 10 items: Human relationships, Imitation, Emotional expression, Sudden physical
movement, Fixative behavior, Adaptation to change, Visual response, Fear or nervousness,
and Verbal and nonverbal communication. After taking part in the PEHR program for several
months, all subjects showed remarkably improved HEIM scores and marked improvements were
observed in eye contact with others (instructors, side walkers, and leaders) in the riding
area. A statistical difference was found in items 1, 2, 3, 6, 7, 8, and 9. However, no
statistical difference was found in items 4, 5, and 10. As the program progressed, the
children showed enhanced verbal and nonverbal communication skills, and became more
expressive in their emotional and empathetic interaction with their parents. These
observations suggest that the normal functioning of pleasurable emotions and empathy may
facilitate further improvements in joint attention, imitation and empathy, and may result
in successful verbal expression by PDD children. Therefore, horseback riding can play a
very important role in the psycho-educational support required for the communication
ability of PDD children. 相似文献
69.
Takeshi SHIMOSATO Masanori TOHNO Takashi SATO Junko NISHIMURA Yasushi KAWAI Tadao SAITO Haruki KITAZAWA 《Animal Science Journal》2009,80(5):597-604
Immunostimulatory sequences of oligodeoxynucleotides (ODNs), such as CpG ODNs, are potent stimulators of innate immunity. Here, we identified a strong immunostimulatory CpG ODN, which we named MsST, from the lac Z gene of Streptococcus (S.) thermophilus ATCC19258, and we evaluated its immune functions. In in vitro studies, MsST had a similar ability as the murine prototype CpG ODN 1555 to induce inflammatory cytokine production and cell proliferation. In mouse splenocytes, MsST increased the number of CD80+CD11c+and CD86+CD11c+ dendritic cells and CD4+CD25+ regulatory T cells. We also analyzed the effects of MsST on the expression of regulatory cytokines by real-time quantitative PCR. MsST was more potent at inducing interleukin-10 expression than the ODN control 1612, indicating that MsST can augment the regulatory T cell response via Toll-like receptor 9, which plays an important role in suppressing T helper type 2 responses. These results suggest that S. thermophilus , whose genes include a strong Immunostimulatory sequence-ODN, is a good candidate for a starter culture to develop new physiologically functional foods and feeds. 相似文献
70.
为了从原子尺度弄清楚因辐射损伤而出现的第二相铜沉淀物对位错运动状况的影响,在Osetsky模型和Malerba势能基础上,通过共轭梯度法进行能量最小化,对BCC铁中刃型位错与铜沉淀物的相互作用进行了模拟.再现作用过程的同时,重点探讨了铜沉淀物直径、间距等因素对相互作用的影响,并将模拟结果与连续体理论模型进行了对比分析.结果表明:铜沉淀物直径越大,相互作用越强,位错越难越过沉淀物.而铜沉淀物间距越大,位错越容易越过沉淀物,Malerba势能下的模拟结果相比Ackland势能下的模拟结果与连续体理论模型结果相符得更好. 相似文献