全文获取类型
收费全文 | 742篇 |
免费 | 45篇 |
国内免费 | 1篇 |
专业分类
林业 | 42篇 |
农学 | 44篇 |
116篇 | |
综合类 | 49篇 |
农作物 | 107篇 |
水产渔业 | 56篇 |
畜牧兽医 | 339篇 |
园艺 | 9篇 |
植物保护 | 26篇 |
出版年
2023年 | 5篇 |
2022年 | 22篇 |
2021年 | 26篇 |
2020年 | 15篇 |
2019年 | 13篇 |
2018年 | 19篇 |
2017年 | 28篇 |
2016年 | 22篇 |
2015年 | 31篇 |
2014年 | 39篇 |
2013年 | 46篇 |
2012年 | 43篇 |
2011年 | 51篇 |
2010年 | 30篇 |
2009年 | 28篇 |
2008年 | 59篇 |
2007年 | 48篇 |
2006年 | 38篇 |
2005年 | 43篇 |
2004年 | 39篇 |
2003年 | 36篇 |
2002年 | 29篇 |
2001年 | 20篇 |
2000年 | 14篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1993年 | 2篇 |
1992年 | 7篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有788条查询结果,搜索用时 15 毫秒
761.
Avian haemosporidian parasites infection in wild birds inhabiting Minami-daito Island of the Northwest Pacific, Japan 总被引:1,自引:0,他引:1
Murata K Nii R Yui S Sasaki E Ishikawa S Sato Y Matsui S Horie S Akatani K Takagi M Sawabe K Tsuda Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2008,70(5):501-503
Haemosporidian parasites infection among wild birds inhabiting Minami-daito Island was studied. Blood films from 183 birds representing 4 species of 4 families were examined microscopically. Avian haemosporidian parasites were detected in 3 species with an overall prevalence of 59.6%. None of the 30 Daito scops owls (Otus scops interpositus) examined were infected. Either Haemoproteus sp. or Plasmodium sp. infection was found in 14 of 31 (45.2%) Borodino islands white-eyes (Zosterops japonicus daitoensis). Plasmodium spp. were found in 94 of 102 (92.2%) bull-headed shrikes (Lanius bucephalus) and 1 of 20 (5%) tree sparrows (Passer montanus). 相似文献
762.
Jae Sung Park Eunji Cho Ji-Yeon Hwang Sung Chul Park Beomkoo Chung Oh-Seok Kwon Chung J. Sim Dong-Chan Oh Ki-Bong Oh Jongheon Shin 《Marine drugs》2021,19(1)
Six new bis(indole) alkaloids (1–6) along with eight known ones of the topsentin class were isolated from a Spongosorites sp. sponge of Korea. Based on the results of combined spectroscopic analyses, the structures of spongosoritins A–D (1–4) were determined to possess a 2-methoxy-1-imidazole-5-one core connecting the indole moieties, and these were linked by a linear urea bridge for spongocarbamides A (5) and B (6). The absolute configurations of spongosoritins were assigned by electronic circular dichroism (ECD) computation. The new compounds exhibited moderate inhibition against transpeptidase sortase A and weak inhibition against human pathogenic bacteria and A549 and K562 cancer cell lines. 相似文献
763.
Bing Han Jiao Wang Yafei Li Xiaoding Ma Sumin Jo Di Cui Yanjie Wang Dongsoo Park Youchun Song Guilan Cao Xingsheng Wang Jianchang Sun Dongjin Shin Longzhi Han 《Euphytica》2018,214(4):74
Two recombinant inbred line F10 rice populations (IAPAR-9/Akihikari and IAPAR-9/Liaoyan241) were used to identify quantitative trait loci (QTLs) for ten drought tolerance traits at the budding and early seedling stage under polyethylene glycol-induced drought stress, and two traits of leaf rolling index (LRI) and leaf withering degree (LWD) under field drought stress. The results showed that the drought-tolerance capacity of IAPAR-9 was stronger than that of Akihikari and Liaoyan241. Thirty-four QTLs for 12 drought tolerance traits were detected, and among them, in the IAPAR-9/Akihikari population, qLRI9-1 and qLRI10-1 for LRI were repeatedly detected in RM3600-RM553 on chromosome 9 and in RM6100-RM3773 on chromosome 10, respectively, at two times points of July 31 and August 13 in 2014. The two QTLs are stable against the environmental impact, and qLRI9-1 and qLRI10-1 explained 6.77–13.66% and 5.01–8.32% of the phenotypic variance, respectively, at the two times points. qLWD9-2 for LWD in the IAPAR-9/Liaoyan241 population contributed 8.73% of variation was detected in the same marker interval with the qLRI9-1, and qLRI1-1 for LRI and qLWD1-1 for LWD were located in the same marker interval RM11054-RM5646 on chromosome 1, which contributed 18.82 and 5.78% of phenotype variation respectively. qGV3 for germination vigor and qRGV3 for relative germination vigor at the budding stage were detected in the same marker interval RM426-RM570 on chromosome 3, which explained 14.98 and 16.30% of the observed phenotypic variation respectively, representing major QTLs. The above-mentioned stable or major QTLs regions could be useful for molecular marker assisted selection breeding, fine mapping, and cloning. 相似文献
764.
Shin Hiratsuka 《Euphytica》1992,62(2):103-110
Summary This paper describes some characteristics of a stylar protein associated with the S2 self-incompatibility allele (S2-protein) in Japanese pear reported earlier (Hiratsuka, 1992). The term style refers to style plus stigma in this paper unless indicated otherwise.The S2-protein, which is a relatively major component of styles with a pI of 6.5, was present only in the style, and the stigmatic zone involved the protein much higher in quantity than upper half of the style, followed by lower half. Molecular weight was assumed to be 24,000 judged from migration distance in sodium dodecyl sulfate (SDS) polyacrylamide gel. Immature styles from 8 to 4 days before anthesis also contained the protein though the amount was relatively small. Neither the heat treatment of prepollinated styles nor the pollination (compatible or incompatible) altered the pI value and staining concentration of S2-protein in the gel. The protein did not have so strong ribonuclease (RNase) activity as reported in S-proteins of Nicotiana alata (McClure et al., 1989) and the RNase activities of extractable stylar proteins from self-incompatible strains were almost the same as those from self-compatible strains.Abbreviations CBB
Coomassie Brilliant Blue
- IEF-PAGE
isoelectricfocusing polyacrylamide gel electrophoresis
- RNase
ribonuclease
- SDS-PAGE
sodium dodecyl sulfate polyacrylamide gel electrophoresis 相似文献
765.
Lichao Wu Jie Liu Atsushi Takashima Keiichi Ishigaki Shin Watanabe 《Annals of Forest Science》2013,70(5):535-543
?Context
Selective logging followed by natural regeneration is rarely employed for restocking subtropical evergreen broad-leaved forests in East Asia compared with the use of clear-cutting.?Aims
To clarify the succession of these forests, the effects of selective logging on stand structure, species diversity, and community similarity were studied in a mature and regenerating forest in Okinawa, Japan.?Methods
Four study plots were established, and trees ≥1.2 m height were identified by species name, tree height, and diameter at breast height.?Results
The results showed that the species composition of regenerating forest was similar to mature forest; however, the former had a greater species density and Shannon–Wiener index than the latter. Castanopsis sieboldii and Distylium racemosum, the predominant trees in the mature forest, continued to dominate the regenerating forest, with a broad layer distribution. High Sørensen and Jaccard community similarity indices for mature and regenerating forest indicated that the regeneration occurred in a progressive succession.?Conclusion
The similar species composition and stand structure for both mature and regenerating forest, and the higher species diversity for the latter, provided no evidence of forest degeneration and suggested that the regenerating forest may develop into a stand similar to preselective logging forest. 相似文献766.
Dhungana Sanjeev K. Kim Hong-Sik Kang Beom-Kyu Seo Jeong-Hyun Kim Hyun-Tae Oh Jae-Hyeon Shin Sang-Ouk Baek In-Yeol 《Journal of Crop Science and Biotechnology》2021,24(1):83-91
Journal of Crop Science and Biotechnology - Flooding stress causes severe yield reduction in soybean worldwide. The development of stress-tolerant cultivars could be an effective measure to reduce... 相似文献
767.
Status of freshwater fish around the Korean Demilitarized Zone and its implications for conservation
- 1. The Korean Demilitarized Zone (DMZ), which divides the Korean peninsula, currently serves as a sanctuary for diverse biological resources, owing to limited development and human activities. The fish fauna of the DMZ areas, including the Civilian Control Zone (CCZ) and Military Facility Protection Area (MFPA), was investigated by quarterly sampling at 53 sites from August 2001 to May 2004.
- 2. In total, 10 946 fish were collected and classified into 99 species and 26 families. Zacco platypus (relative abundance, RA 18.6%) was the dominant species, while other key species were Rhynchocypris steindachneri (16.0%), Pungitius sinensis (12.5%) and Zacco temmincki (8.5%).
- 3. Thirty species were found to be Korean endemics, representing seven families. Eight Korean vulnerable species and two Korean natural monument species were recorded. Three exotic fish species (Carassius cuvieri, Micropterus salmoides and Lepomis macrochirus) were collected at 13 study sites, all but one of which are outside the CCZ. There were significant relationships between altitude and fish species richness (r2=0.448, P<0.001) and the number of endemic fish species (r2=0.487, P<0.001).
- 4. Owing to very limited human interference, the DMZ could provide good benchmark sites to enable ecological restoration on other rivers and streams for maintenance of natural freshwater fish biodiversity. It is suggested that a natural park is instituted around the DMZ areas for ecological protection and as a symbol of peaceful coexistence between South and North Korea.
768.
Hwang W Kim H Lee E Lim J Roh S Shin T Hwang K Lee B 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2000,62(1):1-5
This study was conducted to purify a tissue inhibitor of metalloproteinase (TIMP)-1 in a serum-free medium conditioned with bovine oviduct epithelial cells (BOEC) and to evaluate its effect on development of "HanWoo" (Bos taurus coreanae) embryos to the blastocyst stage. In the first study using SDS-PAGE electrophoresis, the presence of 32 kDa proteins, which contains TIMP-1, was detected in the medium conditioned with BOEC, and TIMP-1 was then purified from the medium by gel filtration and HPLC techniques. When examined TIMP-1 secretion, fluorescent foci indicating the secretion of TIMP-1 were found after stained BOEC with fluorescein isothiocyanate. In the next experiment, two-cell embryos derived from in vitro-fertilization were cultured in a serum-free medium, to which 0, 1.25, 2.5 or 5 microg/ml of purified TIMP-1 was supplemented. More (P<0.05) embryos developed to the morula and blastocyst stages after the addition of 2.5 microg/ml to culture medium than after no addition. In conclusion, our data indicate that BOEC secrete TIMP-1 and this glycoprotein promotes the prehatched development of "HanWoo" embryos derived from in vitro-fertilization. 相似文献
769.
J A Teare W S Schwark S J Shin D L Graham 《American journal of veterinary research》1985,46(12):2639-2643
After a single IV or IM dose of a long-acting oxytetracycline (OTC) preparation, serum concentrations were determined at various times in the ring-necked pheasant, great horned owl, and Amazon parrot. Pharmacokinetic parameters, including serum half-life (t1/2) and apparent volume of distribution (Vd) were calculated from the OTC concentration-time curves for each species and route of administration. Significant differences (P less than 0.05) were found in the t1/2 and Vd parameters between species and routes of administration. Dosage regimens to maintain minimum OTC concentration of 5 micrograms/ml of serum were calculated from the t 1/2 and Vd values obtained, using steady-state pharmacokinetics. In the pheasant, the calculated mean IV dose was 23 mg/kg of body weight every 6 hours, whereas the mean IM dose was 43 mg/kg every 24 hours. The mean IM dose was 16 mg/kg every 24 hours for the owl and 58 mg/kg every 24 hours for the parrot. The small volumes required for treatment, the long-dosing interval obtainable, and the broad spectrum of antimicrobial activity of the long-acting OTC preparation studied offered major advantages over other antibiotics commonly used in treating avian species. 相似文献
770.
Ahmad Yar Qamar Xun Fang Seonggyu Bang Sang Tae Shin Jongki Cho 《Reproduction in domestic animals》2020,55(9):1163-1171
Astaxanthin is a member of the carotenoid family well known for its anti-cancer, anti-diabetic, anti-inflammatory and antioxidant nature. This study was designed to investigate the effects of astaxanthin supplementation of the extender (buffer 2) on post-thaw dog semen quality. Semen from four healthy dogs was collected by digital manipulation twice a week. The ejaculates were pooled, washed, divided into four equal aliquots, diluted with the extender supplemented with different concentrations of astaxanthin (0, 0.5, 1 and 2 µM) and cryopreserved. The results showed that 1 µM astaxanthin was the optimum concentration that led to significantly higher (p < .05) post-thaw motility, kinematic parameters and viability than the other groups. In comparison with the control group, sperm samples supplemented with 1 µM astaxanthin showed significantly higher (p < .05) sperm counts with intact membranes (55.7 ± 0.6% vs. 51.3 ± 0.9%), intact acrosome (58.4 ± 0.7% vs. 53.5 ± 0.6%), active mitochondria (54.9 ± 0.5% vs. 42.6 ± 0.6%) and normal chromatin (67.6 ± 0.9% vs. 61.7 ± 0.6%). Furthermore, astaxanthin-supplemented samples showed significantly lower expression levels (p < .05) of pro-apoptotic (BAX), oxidative induced DNA damage repair (OGG1), oxidative stress-related (ROMO1) genes and higher expression levels of anti-apoptotic (BCL2), and sperm acrosome-associated (SPACA3) genes compared to the control. Thus, supplementation of 1 µM astaxanthin in semen extender results in improved freeze-thaw sperm quality of the dog. 相似文献