全文获取类型
收费全文 | 355篇 |
免费 | 13篇 |
国内免费 | 1篇 |
专业分类
林业 | 53篇 |
农学 | 12篇 |
32篇 | |
综合类 | 15篇 |
农作物 | 10篇 |
水产渔业 | 55篇 |
畜牧兽医 | 162篇 |
园艺 | 5篇 |
植物保护 | 25篇 |
出版年
2023年 | 2篇 |
2022年 | 11篇 |
2021年 | 19篇 |
2020年 | 11篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 11篇 |
2016年 | 15篇 |
2015年 | 13篇 |
2014年 | 17篇 |
2013年 | 20篇 |
2012年 | 21篇 |
2011年 | 27篇 |
2010年 | 11篇 |
2009年 | 11篇 |
2008年 | 7篇 |
2007年 | 16篇 |
2006年 | 22篇 |
2005年 | 28篇 |
2004年 | 21篇 |
2003年 | 18篇 |
2002年 | 13篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有369条查询结果,搜索用时 15 毫秒
111.
Recently, it is documented that bamboo (Mousouchiku:Phyllostachys pubescens Mazel) invasion deteriorates ecological and/or landscape diversity. In order to investigate the ecological effects on forest-floor
arthropods caused by bamboo invasion, we compared the myrmecofauna among broadleaf forests, bamboo-broadleaf mixed forests,
and bamboo forests in Hiroshima City and its vicinity. Myrmecofauna in bamboo forests were more impoverished than in broadleaf
forests. Myrmecofauna in the mixed forests, however, were similar to that in broadleaf forests in both species diversity and
species composition. The change in myrmecofauna may occur relatively late after the initial bamboo invasion. 相似文献
112.
Heng Xu Tetsuya Nakao Chiaki Tanaka Masahiro Yoshinobu Hiroyuki Katayama 《Journal of Wood Science》1998,44(5):343-347
Short carbon fibers, a reinforced material in wood veneer composites, were used to investigate the effects of fiber length and orientation of fibers on the elasticity of plywood. The technical feasibility, elasticity, and strength of the reinforced plywood with short carbon fiber were evaluated. In a short fiber reinforcement system, the fiber length does not directly influence the reinforcement in Cox's theory when the fiber length exceeded a certain length. When the length of short carbon fiber is beyond 3 mm, the high reinforced result was obtained in the experiment. However, if fiber length was too long, the reinforced result was less owing to the bridge between fibers and the increase of holes. The optimum fiber length must be considered. The orientation of fibers has a strong influence on the reinforcement. Unidirectional, perpendicular, and random orientation displayed different influence on the elasticity. Experimental results were discussed with Cox's method. Reinforced plywood with short carbon fibers in random orientation has a higher shear modulus and bending strength than the controls, in addition to other mechanical properties. 相似文献
113.
Tetsuya Yamada Kazuyoshi Hosaka Kumi Nakagawa Noriyo Kaide Shuji Misoo Osamu Kamijima 《Euphytica》1998,102(2):239-246
Eleven somatic hybrids (2n = 68 to 74) obtained between S. tuberosum ssp. tuberosum cv. Dejima (2n = 48) and ATDH-1 (2n =
24), an anther-culture-derived dihaploid of S. acaule (Yamada et al., 1997), were characterized by nuclear RFLP markers using
49 single-copy DNA probes distributed throughout the potato genome (2 to 6 probes per chromosome). One of the somatic hybrids,
DA8-2, had 72 chromosomes and all the Dejima- and ATDH-1-specific markers (124 and 103 bands, respectively), suggesting the
presence of a whole set of both parental chromosomes. The other somatic hybrids lost varying numbers of markers up to seventeen.
The pattern of the loss of markers indicated the elimination of five chromosomes among four somatic hybrids. A nucleolar organizer
region of chromosome 2 was often eliminated in the somatic hybrids. The somatic hybrids studied here had higher frequencies
of multivalent formation than the S. tuberosum parent. They had reasonably good seed set when pollinated with S. tuberosum
pollen. Hence, homoeologous recombination between S. acaule and S. tuberosum chromosomes is possible and useful traits from
S. acaule may be transferred to the S. tuberosum gene pool.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
114.
Stock enhancement programme for black sea bream, Acanthopagrus schlegelii (Bleeker), in Hiroshima Bay, Japan: a review 总被引:1,自引:0,他引:1
This paper reviews the stock enhancement programme for black sea bream ( Acanthopagrus schlegelii ) in Hiroshima Bay. This bay is one of the biggest production areas for black sea bream in Japan, accounting for about 10% of the total catch of the species in this country in 2004. After intensive fishing pressure caused a drastic decline in the catch of the species in this bay in the 1970s, a stock enhancement programme was conducted in its northern part since 1982 to restore the depleted population. The number of black sea bream juveniles released in 1996 surpassed 9 million, representing the third main species stocked in Japan. Almost 1.4 million of these juveniles were released into Hiroshima Bay. The fast acclimatization of hatchery-reared juveniles released into the bay may have contributed to the recovery of landings in the late 1980s and 1990s. However, this recovery was accompanied by a reduction in the market price of black sea bream. Further studies to assess the effectiveness of the stock enhancement programme as well as the carrying capacity of Hiroshima Bay to maintain the stock of black sea bream at a stable, healthy level are desirable. The necessity of evaluating the secondary effects derived from using a reduced number of breeders as well as finding new markets are suggested. 相似文献
115.
Kensuke Hirose Satoshi Mikawa Naohiko Okumura Go Noguchi Kazuo Fukawa Naoe Kanaya Ayumi Mikawa Aisaku Arakawa Tetsuya Ito Yoichi Hayashi Fumio Tachibana Takashi Awata 《Animal Science Journal》2013,84(3):213-221
Vertnin (VRTN) is involved in the variation of vertebral number in pigs and it is located on Sus scrofa chromosome 7. Vertebral number is related to body size in pigs, and many reports have suggested presence of an association between body length (BL) and meat production traits. Therefore, we analyzed the relationship between the VRTN genotype and the production and body composition traits in purebred Duroc pigs. Intramuscular fat content (IMF) in the Longissimus muscle was significantly associated with the VRTN genotype. The mean IMF of individuals with the wild‐type genotype (Wt/Wt) (5.22%) was greater than that of individuals with the Wt/Q (4.99%) and Q/Q genotypes (4.79%). In addition, a best linear unbiased predictor of multiple traits animal model showed that the Wt allele had a positive effect on the IMF breeding value. No associations were observed between the VRTN genotype and other production traits. The VRTN genotype was related to BL. The Q/Q genotype individuals (100.0 cm) were longer than individuals with the Wt/Q (99.5 cm) and Wt/Wt genotypes (98.9 cm). These results suggest that in addition to the maintenance of an appropriate backfat thickness value, VRTN has the potential to act as a genetic marker of IMF. 相似文献
116.
Assessment of bovine X- and Y-bearing spermatozoa in fractions by discontinuous percoll gradients with rapid fluorescence in situ hybridization 总被引:1,自引:0,他引:1
Kobayashi J Oguro H Uchida H Kohsaka T Sasada H Sato E 《The Journal of reproduction and development》2004,50(4):463-469
This study was designed to apply the method of discontinuous Percoll gradients for sex preselection in bovine semen by using a current developed molecular technique, fluorescence in situ hybridization (FISH). In addition, we attempted to amplify the level of enrichment of X- or Y-bearing spermatozoa by treating for activating sperm motility performance with 10 mM caffeine. Bovine spermatozoa were fractionated on Percoll gradients into two major subpopulations of motile spermatozoa (bottom fraction) and weak motile spermatozoa (top fraction). The percentage of Y-bearing spermatozoa in the top fraction (52.9%) slightly exceeded and that in the bottom fraction (44.3%) decreased significantly (P<0.001) compared with the theoretical ratio (50:50). Washing sperm with BO medium affected a deviation between the two sex populations, whereas semen activated with caffeine showed no difference in the percentage of X- and Y-bearing spermatozoa in both fractions compared with the theoretical ratio (50:50). These results show that the proportion of X- and Y-bearing bovine spermatozoa can deviate after discontinuous Percoll gradients, although the proportion of X- and Y-bearing bovine spermatozoa was affected by sperm motility of the sample applied. 相似文献
117.
Yasumitsu MASUDA Ryo HASEBE Yasushi KUROMI Masayoshi KOBAYASHI Misaki IWAMOTO Mitsugu HISHINUMA Tetsuya OHBAYASHI Ryo NISHIMURA 《The Journal of reproduction and development》2021,67(2):149
While embryo transfer (ET) is widely practiced, many of the transferred embryos fail to develop in cattle. To establish a more effective method for selecting bovine embryos for ET, here we quantified morphological parameters of living embryos using three-dimensional (3D) images non-invasively captured by optical coherence tomography (OCT). Seven Japanese Black embryos produced by in vitro fertilization that had reached the expanded blastocyst stage after 7 days of culture were transferred after imaged by OCT. Twenty-two parameters, including thickness and volumes of the inner cell mass, trophectoderm, and zona pellucida, and volumes of blastocoel and whole embryo, were quantified from 3D images. Four of the seven recipients became pregnant. We suggest that these 22 parameters can be potentially employed to evaluate the quality of bovine embryos before ET. 相似文献
118.
Tetsuya Nakao Cicilia Maria Erna Susanti Hiroshi Yoshihara 《Journal of Wood Science》2012,58(5):453-458
The failure behavior of wood with a short crack was examined by conducting the single-edge-notched bending tests of a radial-longitudinal system on Agathis specimens. In the test, the mode I critical stress intensity factor was measured, and its validity was checked by the result from double cantilever beam testing method. The mode I critical stress intensity factor decreased when the crack length approached zero. With crack length correction, a constant critical stress intensity factor was obtained over a wide range of crack length including crack-free specimen. 相似文献
119.
Shoko Fukuda Tetsuya Kobayashi Ian D. Robertson Fukiko Oshima Eri Fukazawa Yuko Nakano Shin Ono Donald E. Thrall 《Veterinary radiology & ultrasound》2014,55(4):374-379
The purpose of this retrospective study was to describe pre‐ and postcontrast computed tomographic (CT) characteristics of confirmed nonparenchymal hemangiosarcoma in a group of dogs. Medical records were searched during the period of July 2003 and October 2011 and dogs with histologically confirmed nonparenchymal hemangiosarcoma and pre‐ and postcontrast CT images were recruited. Two observers recorded a consensus opinion for the following CT characteristics for each dog: largest transverse tumor diameter, number of masses, general tumor shape, character of the tumor margin, precontrast appearance, presence of dystrophic calcification, presence of postcontrast enhancement, pattern of postcontrast enhancement, presence of regional lymphadenopathy, and presence of associated cavitary fluid. A total of 17 dogs met inclusion criteria. Tumors were located in the nasal cavity, muscle, mandible, mesentery, subcutaneous tissue, and retroperitoneal space. Computed tomographic features of nonparenchymal hemangiosarcoma were similar to those of other soft tissue sarcomas, with most tumors being heterogeneous in precontrast images, invasive into adjacent tissue, and heterogeneously contrast enhancing. One unexpected finding was the presence of intense foci of contrast enhancement in 13 of the 17 tumors (76%). This appearance, which is not typical of other soft tissue sarcomas, was consistent with contrast medium residing in vascular channels. Findings indicated that there were no unique distinguishing CT characteristics for nonparenchymal hemangiosarcoma in dogs; however, the presence of highly attenuating foci of contrast enhancement may warrant further investigation in prospective diagnostic sensitivity and treatment outcome studies. 相似文献
120.
Tsuyoshi Ogasawara Tetsuya Hirano Toshio Akiyama Shigeru Arai Masatomo Tagawa 《Fish physiology and biochemistry》1989,7(1-6):309-313
Freshwater adaptability of chum salmon was examined in juvenile fish reared in seawater for 4 months. The fish, weighing about
40g, were transferred directly to fresh water in October, when their cohorts are migrating in the North Pacific Ocean. Plasma
sodium concentration decreased from 167 mM in seawater to about 130 mM during the first 24h, and increased gradually during
2–7 days after the transfer. No immunoreactive prolactin (PRL) was detected in the plasma of the seawater-adapted fish nor
during the first 24h in fresh water. Significant levels of PRL were detected after 2–3 days. The maximal level (2.6 ng/ml)
was observed after 5 days and became undetectable again after 7 days; no significant correlation was seen between the changes
in plasma sodium and PRL levels during the transfer. Plasma growth hormone levels were relatively constant, except for a significant
decrease 12h after the transfer. Although plasma thyroxine levels were highly variable during the experiment, a significant
decrease and an increase were observed 12h and 5 days after the transfer, respectively. The present study indicates that juvenile
chum salmon retain hyperosmoregulatory ability even after prolonged rearing in seawater. Examination of turnover rates, rather
than changes in plasma levels, seems to be essential to clarify the osmoregulatory roles of the hormones. 相似文献