全文获取类型
收费全文 | 489篇 |
免费 | 12篇 |
国内免费 | 2篇 |
专业分类
林业 | 30篇 |
农学 | 12篇 |
基础科学 | 1篇 |
84篇 | |
综合类 | 14篇 |
农作物 | 6篇 |
水产渔业 | 70篇 |
畜牧兽医 | 261篇 |
植物保护 | 25篇 |
出版年
2022年 | 4篇 |
2021年 | 38篇 |
2020年 | 8篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 23篇 |
2014年 | 29篇 |
2013年 | 65篇 |
2012年 | 22篇 |
2011年 | 28篇 |
2010年 | 12篇 |
2009年 | 13篇 |
2008年 | 32篇 |
2007年 | 21篇 |
2006年 | 26篇 |
2005年 | 27篇 |
2004年 | 29篇 |
2003年 | 25篇 |
2002年 | 24篇 |
2001年 | 10篇 |
2000年 | 15篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有503条查询结果,搜索用时 406 毫秒
491.
Yasuo Suto 《Journal of Forest Research》1997,2(1):59-65
In order to confirm the pathogenicity ofCistella japonica, inoculation experiments were conducted onto several coniferous trees. Resinous lesions similar to those of the resinous
stem canker developed by the inoculation withCi. japonica only onChamaecyparis obtusa. Chamaecyparis trees were heavily affected when inoculated with the fungus in November, but slightly in May and August. Resin flows occurred
when inocula ofCi. japonica were put into the holes made on stem barks and on pruning scars. Isolates ofCi. japonica varied greatly in the pathogenicity. On the lesions caused by the fungus, resinous and necrotic areas expanded in fusiform
or oblong shape, and resin cysts were formed in inner barks. Beneath some necrotic inner barks, sapwood was suppressed in
growth for the damages in cambial cells and stained.Ci. japonica was reisolated from the inoculated lesion tissues, though isolation frequency of the fungus became lower in some lesions
two or more years after the inoculation. The results of these inoculations proved thatCi. japonica was the causal agent of the resinous stem canker ofCh. obtusa. 相似文献
492.
Ohta K Onoda S Hirose K Sinmyo R Shimizu K Sata N Ohishi Y Yasuhara A 《Science (New York, N.Y.)》2008,320(5872):89-91
Recent discovery of a phase transition from perovskite to post-perovskite suggests that the physical properties of Earth's lowermost mantle, called the D' layer, may be different from those of the overlying mantle. We report that the electrical conductivity of (Mg0.9Fe0.1)SiO3 post-perovskite is >10(2) siemens per meter and does not vary greatly with temperature at the conditions of the D' layer. A post-perovskite layer above the core-mantle boundary would, by electromagnetic coupling, enhance the exchange of angular momentum between the fluid core and the solid mantle, which can explain the observed changes in the length of a day on decadal time scales. Heterogeneity in the conductivity of the lowermost mantle is likely to depend on changes in chemistry of the boundary region, not fluctuations in temperature. 相似文献
493.
Teratogenic effects of isolated and combined short‐term hypercapnia and hypoxia on red sea bream (Pagrus major) embryos
下载免费PDF全文
![点击此处可从《Aquaculture Research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Some vertebral anomalies in cultured fish arise from unusual environmental conditions during embryogenesis. We investigated the individual and combined teratogenic effects of short‐term hypercapnia and hypoxia on embryos of red sea bream (RSB), Pagrus major. Ten‐somite stage embryos were exposed to hypercapnia (60 and 120 mg/L dissolved carbon dioxide: DCD) and hypoxia (0%, 10%, 25%, 50%, and 75% dissolved oxygen: DO) independently and concomitantly for seven different periods (0, 30, 60, 90, 120, 150 and 180 min) to examine somitic disturbances at hatching, which are prodromal symptoms of centrum defects. Another experiment examined vertebral anomalies in juveniles raised from eggs exposed to hypercapnia (120 mg/L DCD) and hypoxia (10% DO) independently and concomitantly. Short‐time exposures (30–180 min) to hypercapnia (60 and 120 mg/L) and hypoxia (10% DO or less) independently and additively caused larval somitic disturbances and juvenile centrum defects. The results indicate that short‐term hypercapnia and hypoxia generally have the same teratogenic effect on embryos, although there were some differences in the locations of the somitic disturbances and centrum defects, with additive teratogenicity when the conditions were combined. These results suggest the necessity of maintaining appropriate DCD and DO concentrations during egg incubation and transport and during reproduction in recirculating aquaculture. 相似文献
494.
Sample size required for marker assisted selection in improving quantitative traits of self-fertilizing species 总被引:2,自引:0,他引:2
The efficiency of selection for desired trait genotypes in a molecular marker assisted selection for a quantitative trait
in self-fertilizing crop is considered. The QTLs controlling the trait were assumed to be unlinked. It was supposed that the
selection starts in F2, derived from a cross between inbred lines, and this selection will terminate if one or more plants with the desired trait
genotype is found. If no plant with the desired trait genotype is found in F2 then the selection is continued in the F3 progeny that is derived from a single selected F2 plant. Which F2 plant is to be selected was determined according to the rank which is related to the marker genotype of the F2 plants. And this rank was based on the expected frequency of the desired trait genotype in the progeny. The plant with the
top rank among all F2 plants is then selected with the first priority. Additionally the number of F3 plants in the progeny was set to be equal to the number of plants that are required for detecting one or more plants with
the desired trait genotype with a given probability. The probability of getting at least one plant with the desired trait
genotype is expressed as a function of the number of F2 plants (N).The required value for N and the total number of plants (T) in F2 and F3 for detecting at least one plant with the desired trait genotype were calculated for different situations. T was always smaller
for a single marker than for flanking markers. The minimum of T and monotonous decrease of N can be observed when the cumulative-expected-frequency
of selected marker genotypes of F2 plants increased.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
495.
496.
We estimated the stock size of Japanese sardine ( Sardinops melanostictus ) in the Sea of Japan and East China Sea since 1953 using cohort analysis based on the changes of growth patterns. Growth of Japanese sardine, estimated by using annual rings on archived scales since 1961, showed that body lengths were extremely stunted in the 1980–1987 year-classes. The body length at age 3 from February to April in the 1980–1987 year-classes, a period when the stock size exceeded 4 million tons, was 180.0 ± 2.6 mm (mean ± SD), and in the other year-classes was 195.1 ± 7.6 mm. The body length at age 3 and wet weight of zooplankton in August in the offshore area of the Sea of Japan had a significantly positive correlation. We assumed three scenarios for maturation ratios, and estimated Ricker's spawner–recruitment relationships. We analyzed the correlations between logarithmic recruitment residuals (LNRR) and environmental factors in winter, represented by the North Pacific index (NPI), Aleutian low pressure index (ALPI), Pacific decadal oscillation (PDO), monsoon index (MOI), Arctic oscillation (AO) and Southern oscillation index (SOI). Significant correlations were observed between MOI and LNRR and between AO and LNRR. A combination of strong MOI and weak AO would increase the biomass of phytoplankton and zooplankton and subsequently increase the recruitment of Japanese sardine. 相似文献
497.
Akira GOTO Masaaki TAGAMI Fumiki KATO Tsukasa SUZUKI Takashi YAMAGA Harutaka MURASE Fumio SATO Munkhtuul TSOGTGEREL Tadamasa NIIKURA Tomoe MORIYAMA Akiko CHIBA Ken-ichi WATANABE Nao TSUZUKI Yasuo NAMBO 《Journal of Equine Science》2021,32(4):147
We performed a standing hand-assisted laparoscopic ovariectomy in a draft mare that presented with high serum anti-Müllerian hormone (AMH) level and had an enlarged single cystic ovary. Histopathological examination revealed no tumor cell proliferation in the ovary, but the presence of a large ovarian cyst was confirmed. In the diagnosis of abnormal ovaries in mares, a comprehensive assessment should be performed, including the monitoring of ovarian morphology and biomarkers over time, to determine the disease prognosis and treatment plan. The case of this mare with a nonneoplastic abnormal ovary and increased serum AMH level was rare. We suggest that standing hand-assisted laparoscopic ovariectomy is useful for the removal of large ovaries in draft mares. 相似文献
498.
499.
Genotyping‐by‐sequencing for construction of a new genetic linkage map and QTL analysis of growth‐related traits in Pacific bluefin tuna
下载免费PDF全文
![点击此处可从《Aquaculture Research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Tsubasa Uchino Erina Hosoda Yoji Nakamura Motoshige Yasuike Miyuki Mekuchi Masashi Sekino Atushi Fujiwara Takuma Sugaya Yosuke Tanaka Kazunori Kumon Yasuo Agawa Yoshifumi Sawada Motohiko Sano Takashi Sakamoto 《Aquaculture Research》2018,49(3):1293-1301
Pacific bluefin tuna (Thunnus orientalis) has high market value, but its wild populations have decreased in recent years. The broodstock of Pacific bluefin tuna that were hatched artificially and reared under aquaculture conditions is beginning to be used for production. The creation of broodstock with commercially valuable traits, such as rapid growth, is therefore of great interest. Genetic linkage map‐based identification of markers associated with quantitative trait loci (QTLs) facilitates marker‐assisted selection (MAS) breeding and allows efficient genetic improvement of broodstock. Single nucleotide polymorphism (SNP)‐based genetic linkage map construction using the genotyping‐by‐sequencing method can expand the number of mapped markers and help identify growth‐related QTLs. In this study, we constructed sex‐specific maps for 24 linkage groups consisting of 677 SNP and 651 microsatellite markers. The total lengths of 93 progenies in the mapping population followed normal distribution, with an average length of 9.4 mm. We performed composite interval mapping in the mapping population. QTL analysis revealed one significant QTL in LG10 on the female linkage map. The genetic linkage map—the second such map generated for Pacific bluefin tuna—and the growth‐related QTLs detected in this study will be useful for tuna aquaculture MAS programs. 相似文献
500.
Masashi Ando Yoko Nakagishi Keiko Yoshida Masashi Nakao Takayuki Nakagawa Yasuo Makinodan Yasuyuki Tsukamasa Ken-Ichi Kawasaki 《Fisheries Science》2006,72(5):1104-1108
Pyridinoline (Pyr), one of the mature crosslinks of collagen, was determined in muscular collagen of three species of fish.
The amounts of muscular Pyr in red sea bream, yellowtail, and tiger puffer were 3.4, 8.8, and 50.3 mmol/mol collagen, respectively,
indicating that the Pyr concentration in muscular collagen differs greatly among fish species. The Pyr concentration in tiger
puffer muscular collagen was the greatest, but it was only one-fourth that in rabbit muscle. As in mammalian skin collagen,
Pyr was not detected in skin collagen of red sea bream and yellowtail. However, tiger puffer skin contained Pyr (3.75 mmol/mol
collagen). The presence of Pyr would have a relationship to some features of tiger puffer skin, such as mechanical strength
and thickness. Pyr concentrations in acid-soluble collagen (ASC), pepsin-solubilized collagen (PSC), and insoluble collagen
(ISC) in muscles of three species of fish were determined. Pyr was found in ISC > PSC > ASC, from the highest to the lowest
concentration, and the concentration in ISC was 45–200 times that in ASC. Therefore, Pyr crosslinks that are formed between
collagen molecules would have a close relationship to collagen solubility. 相似文献