全文获取类型
收费全文 | 509篇 |
免费 | 22篇 |
专业分类
林业 | 24篇 |
农学 | 9篇 |
67篇 | |
综合类 | 31篇 |
农作物 | 26篇 |
水产渔业 | 16篇 |
畜牧兽医 | 297篇 |
园艺 | 2篇 |
植物保护 | 59篇 |
出版年
2022年 | 4篇 |
2021年 | 13篇 |
2020年 | 8篇 |
2019年 | 10篇 |
2018年 | 16篇 |
2017年 | 10篇 |
2016年 | 11篇 |
2015年 | 18篇 |
2014年 | 19篇 |
2013年 | 25篇 |
2012年 | 26篇 |
2011年 | 28篇 |
2010年 | 11篇 |
2009年 | 11篇 |
2008年 | 28篇 |
2007年 | 24篇 |
2006年 | 34篇 |
2005年 | 28篇 |
2004年 | 27篇 |
2003年 | 26篇 |
2002年 | 24篇 |
2001年 | 32篇 |
2000年 | 21篇 |
1999年 | 18篇 |
1998年 | 6篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1966年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有531条查询结果,搜索用时 31 毫秒
61.
T. Jaroensong Y. Endo S.‐J. Lee A. Kamida M. Mochizuki R. Nishimura N. Sasaki T. Nakagawa 《Veterinary and comparative oncology》2012,10(4):274-282
To determine the influence of the transplantation site of canine osteosarcoma (OS) cell lines on tumour growth and pulmonary metastasis, three OS cell lines were transplanted into nude mice via subcutaneous (SC), intratibial (IT) or intravenous (IV) injection. IT‐xenografts exhibited greater potential for developing primary masses and pulmonary metastasis than SC‐xenografts. In IT and IV xenografts, lung micrometastases along with phosphorylated ezrin–radixin–moesin (p‐ERM) overexpression were found in mice xenografted with HMPOS and OOS cells after 1 week and metastasis was found with decreased p‐ERM expression at later time points. The expression of ezrin and p‐ERM in the primary tumours of IT‐xenografted mice was higher than those in SC‐xenografted mice with HMPOS and OOS cells. The results suggest that the orthotopic transplantation site plays an important role in the spontaneous metastasis of canine OS and that ezrin phosphorylation may be involved in the early metastatic mechanism of canine OS cells. 相似文献
62.
Bivalves serve as an important aquaculture product, as they are the source of essential fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in our diet. However, their cultivation in the wild can be affected by fouling organisms that, in turn, affect their EPA and DHA content. The effects of fouling organisms on the EPA and DHA contents of cultivated bivalves have not been well documented. We examined the effects of fouling organisms on the EPA and DHA contents and condition index of cultured oysters, Crassostrea gigas, in an aquaculture system. We sampled two-year-old oysters from five sites in Shizugawa Bay, Japan, in August 2014. Most of the fouling organisms were sponges, macroalgae, and Mytilus galloprovincialis. A significant negative relationship existed between the DHA content in C. gigas and the presence of sponges and macroalgae. A lower C. gigas EPA content corresponded to a higher M. galloprovincialis fouling mass and a lower C. gigas condition index. This can be explained by dietary competition between C. gigas and M. galloprovincialis for diatoms, which were the main producer of EPA in our study sites. Our findings indicate that fouling organisms likely reduce the EPA and DHA content in cultivated oysters. Therefore, our results suggest that the current efforts to remove fouling organisms from oyster clusters is an effective strategy to enhance the content of EPA and DHA in oysters. 相似文献
63.
Masako Seki Makiko Chono Tsutomu Nishimura Mikako Sato Yasuhiro Yoshimura Hitoshi Matsunaka Masaya Fujita Shunsuke Oda Katashi Kubo Chikako Kiribuchi-Otobe Hisayo Kojima Hidetaka Nishida Kenji Kato 《Breeding Science》2013,63(3):309-316
The Ppd-A1 genotype of 240 Japanese wheat cultivars and 40 foreign cultivars was determined using a PCR-based method. Among Japanese cultivars, only 12 cultivars, all of which were Hokkaido winter wheat, carried the Ppd-A1a allele, while this allele was not found in Hokkaido spring wheat cultivars or Tohoku-Kyushu cultivars. Cultivars with a photoperiod-insensitive allele headed 6.9–9.8 days earlier in Kanto and 2.5 days earlier in Hokkaido than photoperiod-sensitive cultivars. The lower effect of photoperiod-insensitive alleles observed in Hokkaido could be due to the longer day-length at the spike formation stage compared with that in Kanto. Pedigree analysis showed that ‘Purple Straw’ and ‘Tohoku 118’ were donors of Ppd-A1a and Ppd-D1a in Hokkaido wheat cultivars, respectively. Wheat cultivars recently developed in Hokkaido carry photoperiod-insensitive alleles at a high frequency. For efficient utilization of Ppd-1 alleles in the Hokkaido wheat-breeding program, the effect of Ppd-1 on growth pattern and grain yield should be investigated. Ppd-A1a may be useful as a unique gene source for fine tuning the heading time in the Tohoku-Kyushu region since the effect of Ppd-A1a on photoperiod insensitivity appears to differ from the effect of Ppd-B1a and Ppd-D1a. 相似文献
64.
Shamitha Rao Morey Yoichi Hashida Ryu Ohsugi Junko Yamagishi 《Plant Production Science》2013,16(4):328-338
ABSTRACTThe sugar-accumulating potential of global and local sweet and grain sorghum varieties were tested under the local conditions. The basis for this study was the dependency of sugar accumulation on temperature and photoperiod. Thus, the efficacy of cultivars as a bioenergy source would need to be determined based on their performance under the local environmental conditions. A strong correlation of sucrose content with brix was observed, enabling large-scale screening of varieties for high sucrose content. The morphological characteristics inherent in sweet sorghum, such as tall stems, greater number of leaves and a longer vegetative period, were found to correlate with the total stem sugar content. Assessment of sugars along the stem revealed maximum sugar accumulation in the upper intermediate to upper internodes in most of the varieties tested. The maximum theoretical ethanol yield (MTEY), a function of brix and juice yield, was determined as a better indicator of testing the performance of a variety as a potential source of bioethanol, mainly due to a negative correlation of stem juiciness and sucrose content in the varieties tested. Further, the relative expression of vacuolar invertase genes, SbINV1 and SbINV2, was studied, and a strong negative correlation of SbINV2 to stem sucrose content was observed. This reveals a possibility of involvement of vacuolar invertase gene, SbINV2, in sugar accumulation in sweet sorghum stems, and as a key candidate for molecular breeding studies for higher stem sugar content. 相似文献
65.
Naoaki Yamada Satomi Hashimoto Yuki Tomonari Hiroko Kokoshima Takuya Doi Junko Sato Yumi Wako Minoru Tsuchitani 《Journal of toxicologic pathology》2013,26(3):313-317
A five-month-old male beagle dog suddenly became moribund. Bloody fluid accumulated in the thoracic and abdominal cavities, and soft yellow flecks were floating in the thoracic fluid. The mediastinum and pericardium became dark reddish with villous thickening. Other parietal and pulmonary pleurae were rough, and the organs adhered to each other. Histologically, most mediastinal pleura formed papillary projections covered by a single layer of mesothelial cells. Many macrophages and neutrophils infiltrated the submesothelial connective tissue. At the mediastinum adjacent to the pericardium, cuboidal mesothelial cells proliferated solidly and formed a thick surface stratum. The flecks consisted of gram-negative filamentous or small bacillary (coccoid) bacteria. In the right posterior lobe of the lung, neutrophilic infiltration and a large encapsulated abscess including a bacterial colony were present. We diagnosed this case as “bacterial pleuritis with thickened mesothelial hyperplasia”. The cause of the pleuritis might be a chronic pleural infection spread via the lung abscess. 相似文献
66.
Fuminori TANIHARA Michiko NAKAI Hiroyuki KANEKO Junko NOGUCHI Takeshige OTOI Kazuhiro KIKUCHI 《The Journal of reproduction and development》2013,59(4):385-392
In porcine oocytes, the function of the zona pellucida (ZP) with regard to sperm
penetration or prevention of polyspermy is not well understood. In the present study, we
investigated the effects of the ZP on sperm penetration during in vitro
fertilization (IVF). We collected in vitro-matured oocytes with a first
polar body (ZP+ oocytes). Some of them were freed from the ZP (ZP− oocytes) by two
treatments (pronase and mechanical pipetting), and the effects of these treatments on
sperm penetration parameters (sperm penetration rate and numbers of penetrated sperm per
oocyte) were evaluated. There was no evident difference in the parameters between the two
groups. Secondly, we compared the sperm penetration parameters of ZP+ and ZP− oocytes
using frozen-thawed epididymal spermatozoa from four boars. Sperm penetration into ZP+
oocytes was found to be accelerated relative to ZP− oocytes. Thirdly, we evaluated the
sperm penetration of ZP+ and ZP− oocytes at 1−10 h after IVF (3 h gamete co-incubation).
The proportions of oocytes penetrated by sperm increased significantly with time in both
groups; however, the number of penetrated sperm per oocyte did not increase in ZP−
oocytes. Finally, we performed IVF using ZP− oocytes divided into control (3 h) and
prolonged gamete co-incubation (5 h) groups. Greater numbers of sperm penetrated in the 5
h group than in the control group. These results suggest that the ZP and oolemma are not
competent factors for prevention of polyspermy in our present porcine IVF system. However,
it appears that ZP removal is one of the possibilities for reducing polyspermic
penetration in vitro in pigs. 相似文献
67.
68.
Saiga A Iwai K Hayakawa T Takahata Y Kitamura S Nishimura T Morimatsu F 《Journal of agricultural and food chemistry》2008,56(20):9586-9591
In this study, collagen extracted from chicken legs (which are the yellow keratin parts containing a nail) was hydrolyzed with various enzymes, and the angiotensin I-converting enzyme (ACE)-inhibitory activity of each hydrolysate was determined. The hydrolysate by treatment with an Aspergillus species-derived enzyme had the highest activity (IC 50 = 260 microg/mL). The fraction of this hydrolysate obtained by ultrafiltration with a molecular-weight cutoff of 3000 Da (low fraction) had a stronger activity (IC 50 = 130 microg/mL) than the fractionated one. This fraction was further fractionated by HPLC, and the peptides in the fraction with high ACE-inhibitory activity were identified. The amino acid sequences of the four peptides were identified using a protein sequencer. These peptides were synthesized to confirm their ACE-inhibitory activities; this showed that peptides with a Gly-Ala-Hyp-Gly-Leu-Hyp-Gly-Pro sequence had the highest activity (IC 50 = 29 microM). When the low fraction was administered to spontaneous hypertensive rats, a decrease in their blood pressure was observed after 2 h of administration, and a significant decrease in blood pressure (-50 mmHg) was observed after 6 h. Moreover, long-term administration studies indicated that the low fraction showed a significant suppression of increased blood pressure. 相似文献
69.
Noguchi J Ozawa M Nakai M Somfai T Kikuchi K Kaneko H Kunieda T 《The Journal of reproduction and development》2008,54(3):203-207
A gene for FK506 binding protein 6 (Fkbp6) expresses during a specific stage of male and female meiosis. Disruption of the gene influences male reproduction, i.e. arrests spermatogenesis, but not female reproduction. Using the mouse model (targeted disruption), the role of the gene in homologous chromosome pairing has been demonstrated in a previous study. For further understanding the function of Fkbp6 in chromosome synapsis, we evaluated chromosome pairings during male meiosis in the as/as rat, a spontaneous null mutation, and compared them with those of the mouse model. Electron microscopy of the pachytene nuclei unveiled several types of abnormal chromosome pairing in the rat model, as shown in the mouse previously. The frequencies of aberrant pairings in the knockout mice and mutant rats were 42 of 67 nuclei (62.7%) and 20 out of 74 nuclei (27.0%), respectively. In order to clarify the mechanism of male specific infertility in Fkbp6 deficiency, the localization of gammaH2AX, a marker protein of XY chromosome inactivation during male meiosis, was examined. Immunostaining of gammaH2AX unveiled normal localization of the molecule to XY chromosomes (XY body) in both models, showing the independency of FKBP6 in sex chromosome inactivation. Besides the XY body, focal localization of gammaH2AX was observed in accordance with the unsynapsed chromosomes in both types of null animal. These results indicate the fundamental role of Fkbp6 in homologous chromosome synapsis during male meiosis. In conclusion, male specific infertility under Fkbp6 deficiency remains unsolved. 相似文献
70.
Kaneko H Kikuchi K Nakai M Noguchi J 《The Journal of reproduction and development》2008,54(6):480-485
Clarification of the endocrine status of host mice provides us with basic knowledge with which we can manipulate the growth and function of xenografted testicular tissues. We investigated the hormonal profiles of castrated mice grafted with porcine immature testicular tissues from 30 to 210 or more days after grafting (day 0=castration and grafting). The serum follicle stimulating hormone (FSH) concentrations of the host mice declined (P<0.05) from day 60 compared with those of the castrated, ungrafted mice. The serum inhibin and testosterone levels were higher (P<0.05) than those in the castrated, ungrafted mice from days 30 and 90 days, respectively. The inhibin levels further increased (P<0.05) from day 90, during which time the levels were higher (P<0.05) than those in the intact male mice. In the grafts, formation of lumens occurred in the seminiferous cords on day 90 and spermatozoa appeared in the lumens from day 120. However, spermatogenesis in the grafts did not reach the qualitatively normal levels observed in adult boars. The intensity of the immune reaction to inhibin alpha subunits in the Sertoli cells of the grafts decreased with differentiation of the seminiferous tubules. The present findings indicate that a feedback loop was established between the mouse hypothalamo-pituitary axis and the grafted porcine tissues from 60 days post-grafting. The results also indicate that the serum inhibin levels in the host mice remained high even after the appearance of lumens in the seminiferous tubules of the grafted tissues; this is strikingly different to the situation in normal male animals, in which the serum inhibin levels decline at around the time of tubular differentiation. The lack of efferent ducts in the tubules of the grafted tissues probably caused the accumulation of inhibin to be released into the lumens, resulting in high concentrations of circulating inhibin. These high levels of inhibin may directly affect spermatogenic activity and suppress FSH secretion. 相似文献