全文获取类型
收费全文 | 273篇 |
免费 | 14篇 |
国内免费 | 3篇 |
专业分类
林业 | 38篇 |
农学 | 29篇 |
基础科学 | 3篇 |
66篇 | |
综合类 | 22篇 |
农作物 | 8篇 |
水产渔业 | 13篇 |
畜牧兽医 | 96篇 |
园艺 | 2篇 |
植物保护 | 13篇 |
出版年
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 10篇 |
2019年 | 8篇 |
2018年 | 10篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 16篇 |
2012年 | 11篇 |
2011年 | 8篇 |
2010年 | 3篇 |
2009年 | 8篇 |
2008年 | 23篇 |
2007年 | 14篇 |
2006年 | 16篇 |
2005年 | 16篇 |
2004年 | 14篇 |
2003年 | 16篇 |
2002年 | 10篇 |
2001年 | 15篇 |
2000年 | 19篇 |
1999年 | 9篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1969年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有290条查询结果,搜索用时 15 毫秒
281.
Dezawa M Ishikawa H Itokazu Y Yoshihara T Hoshino M Takeda S Ide C Nabeshima Y 《Science (New York, N.Y.)》2005,309(5732):314-317
Bone marrow stromal cells (MSCs) have great potential as therapeutic agents. We report a method for inducing skeletal muscle lineage cells from human and rat general adherent MSCs with an efficiency of 89%. Induced cells differentiated into muscle fibers upon transplantation into degenerated muscles of rats and mdx-nude mice. The induced population contained Pax7-positive cells that contributed to subsequent regeneration of muscle upon repetitive damage without additional transplantation of cells. These MSCs represent a more ready supply of myogenic cells than do the rare myogenic stem cells normally found in muscle and bone marrow. 相似文献
282.
Kawate N Sakase M Watanabe K Fukushima M Noda M Takeda K Ueno S Inaba T Kida K Tamada H Sawada T 《The Journal of reproduction and development》2007,53(4):811-817
We compared synchronization and pregnancy rates, and the increase in blood progesterone concentrations during luteal development, between (1) Ovsynch plus an intravaginal controlled internal drug release (CIDR) device protocol followed by timed embryo transfer (timed ET), and (2) a conventional estrus synchronization method using PGF(2 alpha) and ET in suckled postpartum Japanese Black beef cows. Cows in the PGF group (n=18) received a PGF(2 alpha) analogue when a CL was first palpated per rectum at 10-d intervals after 1 to 2 month postpartum. Cows (n=11), which showed estrus (Day 0) within 5 d of the PGF(2 alpha), and had a CL on Day 7, received ET. Cows in the Ovsynch+CIDR group (n=19) underwent the Ovsynch protocol plus a CIDR for 7 d (GnRH analogue and CIDR on Day-9, PGF(2alpha) analogue with CIDR removal on Day-2, and GnRH analogue on Day 0), with ET on Day 7. The ovulation synchronization (100%) and embryo transfer (100%) rates in the Ovsynch+CIDR group were greater (P<0.01) than the estrus synchronization (66.7%) and the embryo transfer (61.1%) rates in the PGF group. The postpartum interval at ET in the Ovsynch+CIDR group (62.5 +/- 2.5 d) was shorter (P<0.01) than in the PGF group (74.9 +/- 3.9 d). The pregnancy rate in the Ovsynch+CIDR group (57.9%) did not differ significantly from that in the PGF group (50.0%). Plasma progesterone concentrations were not significantly different in the two groups on Days 0, 1, 2, 5, 7, 14 and 21. In summary, higher synchronization and transfer rates, and shorter postpartum interval to ET, can be achieved with timed ET following the Ovsynch plus CIDR protocol than after estrus with the single PGF(2 alpha) treatment followed by ET in suckled postpartum recipient beef cows. Pregnancy rates were similar. Also, the increase in blood progesterone concentrations during luteal development following ovulation synchronized by the Ovsynch plus CIDR protocol was similar to that after estrus induced by the PGF(2 alpha) treatment. 相似文献
283.
Genotypic variation in polyphenol content of barley grain 总被引:1,自引:0,他引:1
Masaya Fujita Kazuyoshi Takeda Noriko Kohyama Yoshinori Doi Hitoshi Matsunaka 《Euphytica》2002,124(1):55-58
The polyphenol content in pearl barley, which is highly correlated to a browning reaction after heat treatment, was investigated
using 1,347 cultivated barley varieties (H. vulgare) and two wild accessions (H. vulgare subsp. spontaneum) collected from different areas of the world. The polyphenol content in the cultivated barley shows a wide variation ranging
from 0.19 to 0.75 mg/g with a nearly normal frequency distribution. The polyphenol content in the hulless varieties from Japan
and Korea was low. On the other hand, the polyphenol content in wild barley was about two times higher than the average value
recorded in cultivated barley. Based on HPLC analysis, five lowest-polyphenol content local varieties do not represent proanthocyanidin-free
mutants.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
284.
Breadmaking properties (bread height, mm, and specific volume, cm3/g ) showed marked deterioration when bread dough was frozen and stored at ‐20°C for one day. However, these properties of bread dough baked after storage for three to six days were not further deteriorated as compared with that baked after one day of storage. A large amount of liquid was oozed from the frozen‐and‐thawed bread dough. The liquid was separated from the bread dough by centrifugation (38,900 × g for 120 min at 4°C), and collected by tilting the centrifuge tube at an angle of 45° for 30 min. There was a strong correlation between the amount of centrifuged liquid and breadmaking properties (bread height and specific volume). The mechanism responsible for the oozing of liquid in frozen‐and‐ thawed bread dough was studied. The presence of yeast and salt in bread dough was suggested to be closely related to the amount of centrifuged liquid, and fermented products particularly had a large effect on the amount of centrifuged liquid. 相似文献
285.
Akiko Sasaki Shozo Shikenya Kazuhiko Takeda Takayuki Nakatsubo 《Journal of Forest Research》2007,12(1):68-74
To estimate the importance of leaching of dissolved organic matter (DOM) as a pathway through which organic matter is supplied
to stream ecosystems, we examined the amount of leachate over time and chemical properties of DOM leached from leaves in different
conditions. The samples used were green leaves, yellow senescent leaves, and leaf litter of Salix gracilistyla Miq., which is the dominant riparian plant species in the middle reaches of rivers in western Japan. We analyzed dissolved
organic carbon (DOC), total sugar, and polyphenol in the leachate of leaf samples collected from a fluvial bar in the middle
reaches of the Ohtagawa River in Hiroshima Prefecture, Japan. Considerable leaching of DOC from senescent leaves [37.3 mg g−1 dry weight (dw) leaf] and leaf litter (8.1 mg g−1 dw leaf) occurred within 24 h after immersion. In contrast, DOC leached from green leaves was negligible until 1 week after
leaf immersion. Carbon loss of leaves by leaching within 24 h after leaf immersion was estimated to be less than 8%, suggesting
that leaching of DOC from S. gracilistyla leaves is a minor pathway through which organic matter is supplied to stream ecosystems. DOM leached from the leaves included
sugar and polyphenol, which were among the major chemical forms of DOM leached from the leaves (based on the molecular mass).
In a laboratory experiment in which the difference in the stability of DOM between the chemical forms was examined, sugar
decomposed more rapidly than polyphenol. 相似文献
286.
Genetic relationships between temperament of calves at auction and carcass traits in Japanese Black cattle 下载免费PDF全文
Correlations of calves’ temperament with carcass traits were estimated to clarify the genetic relationships between them in Japanese Black cattle. The temperament records for 3128 calves during auction at a calf market were scored on a scale of 1 (calm) to 5 (nervous) as temperament score (TS ), and the TS were divided into two groups (TSG ): TS 1 and 2 comprised TSG 1, and 3 to 5 constituted TSG 2. Carcass data were obtained from 33 552 fattened cattle. A threshold animal model was used for analyzing the underlying liability for TSG , whereas a linear one was used for TS and carcass traits. The heritability estimates for TS and TSG were 0.12 and 0.11, respectively. On the other hand, moderate to high heritability estimates were obtained for carcass traits (0.40 to 0.68). The temperament scores were negatively correlated with carcass weight, rib thickness and subcutaneous fat thickness (?0.13 to ?0.59). In contrast, weak to moderate positive correlations were found between the temperament scores and rib eye area or yield estimate (0.16 to 0.45). The temperament scores and beef marbling score had no correlation. These results showed that it is possible to improve temperament and carcass traits simultaneously. 相似文献
287.
Several varieties of birds are affected by type C botulism. We conducted neutralization tests of culture supernatants of isolates from cases of avian botulism. Whereas the toxin produced by isolates derived from mammalian botulism was neutralized only with type C antitoxin, the toxins of all isolates related to avian botulism were neutralized with both type C and D antitoxins. An analysis of nucleotide sequences with several strains revealed that the neurotoxin gene in the isolates from avian botulism comprises two thirds of the type C neurotoxin gene and one third of the type D neurotoxin gene. This indicates that the neurotoxin of avian isolates is a mosaic of type C and D neurotoxins. We prepared three sets of primers to differentiate the gene for the mosaic form from the conserved genes of type C and D neurotoxins. The results of polymerase chain reaction with these primers indicated that all avian botulism-related isolates and specimens possess the gene for the mosaic form of the neurotoxin. The toxins purified from avian and mammalian isolates exhibited the same degree of lethality in mice, but the former showed greater toxicity to chickens than the latter. These results indicate that the mosaic neurotoxin is probably a pathogenic agent causing some forms of avian botulism. 相似文献
288.
The influence of the physicochemical properties of heat‐moisturetreated and untreated starches from various plant sources on the quality of tempura fried batter was examined. Batter of each starch plus wheat protein (92:8, w/w) was fried. Quality of the resulting fried batter was determined from crispness score, water evaporation, and breaking strength. The crispness score correlated with water evaporation (r = 0.95) and breaking strength (r = 0.97), indicating that water evaporation was a reliable index for evaluation of crispness of fried batter. Determination of water evaporation was easy and simple. The crispness (favorable eating texture) of tempura coating depended largely on starch origin. Among the pasting properties of starch, temperature at maximum viscosity (r = 0.77) and breakdown/maximum viscosity (% breakdown, r = ‐0.82) correlated with water evaporation, suggesting that starch resistant to gelatinization and granule disintegration produced crispy fried batter. This observation was supported by SEM. Water evaporation (r = ‐0.82) and % breakdown (r = 0.95) correlated with degree of amylose gelatinization, indicating that amylose was one of the determinants that controls crispness of fried batter by restraining disintegration of the starch granule structure. 相似文献
289.
Yasushi Yoshimoto Tamami Egashira Isao Hanashiro Hiroshi Ohinata Yoshikazu Takase Yasuhito Takeda 《Cereal Chemistry》2004,81(4):515-520
The molecular structure and pasting properties of starches from eight buckwheat cultivars were examined. Rapid viscograms showed that buckwheat starches had similar pasting properties among cultivars. The actual amylose content was 16–18%, which was lower than the apparent amylose content (26–27%), due to the high iodine affinity (IA) of amylopectin (2.21–2.48 g/100 g). Amylopectins resembled each other in average chain‐length (23–24) and chain‐length distributions. The long‐chains fraction (LC) was abundant (12–13% by weight) in all the amylopectins, which was consistent with high IA values. The amyloses were also similar among the cultivars in number‐average DP 1,020–1,380 with 3.1–4.3 chains per molecule. The molar‐based distribution indicated that all the amyloses comprised two molecular species differing in molecular size, although the weight‐based distribution showed a single species. A comparison of molecular structures of buckwheat starches to cereal starches indicated buckwheat amylopectins had a larger amount of LC, and their distributions of amylose and short chains of amylopectin on molar basis were similar to those of wheat and barley starches. 相似文献
290.
Amylose and amylopectin were prepared from large, medium, and small granule starches of classified waxy barley flour, and their fine structures were investigated. The amylose content had a wide distribution range (≈1.4–9.4%). Number‐average degrees of polymerization (DPn) of the amyloses were similar among the samples (≈1,200–1,300). But number of chains per molecule (NC) decreased from the surface to the center (≈6–10 chains). DPn of the amylopectins varied from 4,657 to 14,604; decreased in the order of large, medium, and small granules in same fractions of the grain; and increased from the surface layer to the center. Longest chains (LC) were not found in any of the amylopectin molecules. The large amylopectin molecule had more long chains and fewer A chains than the small molecule. The amylose content had definite effects on the transition temperature range and crystal formation of the starch granules. There were positive correlations between DPn of the amylopectin and relative crystallinity (γ = +0.69) and enthalpy value (γ = +0.80), respectively. These findings may help to elucidate biosynthesis mechanism of starch. 相似文献