全文获取类型
收费全文 | 436篇 |
免费 | 27篇 |
国内免费 | 1篇 |
专业分类
林业 | 90篇 |
农学 | 12篇 |
基础科学 | 2篇 |
78篇 | |
综合类 | 29篇 |
农作物 | 24篇 |
水产渔业 | 27篇 |
畜牧兽医 | 135篇 |
园艺 | 19篇 |
植物保护 | 48篇 |
出版年
2022年 | 6篇 |
2021年 | 5篇 |
2020年 | 13篇 |
2019年 | 8篇 |
2018年 | 18篇 |
2017年 | 22篇 |
2016年 | 26篇 |
2015年 | 13篇 |
2014年 | 15篇 |
2013年 | 30篇 |
2012年 | 32篇 |
2011年 | 33篇 |
2010年 | 18篇 |
2009年 | 14篇 |
2008年 | 23篇 |
2007年 | 19篇 |
2006年 | 16篇 |
2005年 | 23篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 13篇 |
2001年 | 11篇 |
2000年 | 13篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1990年 | 5篇 |
1988年 | 2篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 3篇 |
1969年 | 3篇 |
1968年 | 3篇 |
1967年 | 1篇 |
1964年 | 1篇 |
1957年 | 1篇 |
1935年 | 2篇 |
1908年 | 1篇 |
排序方式: 共有464条查询结果,搜索用时 15 毫秒
61.
In the present study, selected almond genotypes in Keciborlu/Isparta region by Y?ld?r?m (2007) based on late blooming and superior nut chacteristics were used to evaluate seedling growth performances and the reaction to root knot nematodes. Seeds were planted on perlite medium and stored 60 days at +4 °C in order to break seed dormancy. After germinating, seedlings were transferred to plastic pots to evaluate seedling growth characteristics and remaining seedlings were inoculated with Meloidogyne javanica and Meloidogyne incognita in order to asses resistance status of the selected seedlings. The highest germination percentage was obtained from Genotype 54 (96.1?%), the highest plant was observed from Genotype 9 (62.18 cm), the longest primary root was found from Genotype 54 (30.28 cm), the average secondary root lenght was highest in Genotype 9 (31.04 cm) and the widest root collar was observed in Genotype 33 (8.38 mm). Seedling stem diameter changed between 4.76 mm (Genoype 40) to 7.67 mm (Genotype 33). The lowest variation for stem widht was observed in Genotype 55 (0.58?%) while the lowest variation for seedling hight was found in Genotype 33 (0.50?%). Evaluated almond genotypes showed different reactions to studied nematode species, M. javanica and M. incognita. Resistant reactions of almond genotypes to nematode species were classified as susceptible, tolerant and resistant based on gal index values. Genotype 9 and 31 classified as tolerant to M. javanica while Genotype 54 classified as resistant to M. incognita. 相似文献
62.
Mitchell?A.?Ellison Michael?B.?McMahon Morris?R.?Bonde Cristi?L.?Palmer Douglas?G.?LusterEmail authorView authors OrcID profile 《Plant methods》2016,12(1):37
Background
Rust fungi are obligate pathogens with multiple life stages often including different spore types and multiple plant hosts. While individual rust pathogens are often associated with specific plants, a wide range of plant species are infected with rust fungi. To study the interactions between these important pathogenic fungi and their host plants, one must be able to differentiate fungal tissue from plant tissue. This can be accomplished using the In situ hybridization (ISH) protocol described here.Results
To validate reproducibility using the ISH protocol, samples of Chrysanthemum × morifolium infected with Puccinia horiana, Gladiolus × hortulanus infected with Uromyces transversalis and Glycine max infected with Phakopsora pachyrhizi were tested alongside uninfected leaf tissue samples. The results of these tests show that this technique clearly distinguishes between rust pathogens and their respective host plant tissues.Conclusions
This ISH protocol is applicable to rust fungi and potentially other plant pathogenic fungi as well. It has been shown here that this protocol can be applied to pathogens from different genera of rust fungi with no background staining of plant tissue. We encourage the use of this protocol for the study of plant pathogenic fungi in paraffin embedded sections of host plant tissue.63.
Inheritance and expression of transgenes in T2 and T3 generations of Lotus corniculatus transformed using Agrobacterium tumefaciens 总被引:2,自引:0,他引:2
K. Judith Webb Mervyn O. Humphreys Leif Skøt Margaret Gibbs John Gatehouse 《Euphytica》1999,108(3):169-179
The inheritance and expression of the reporter gene uidA, encoding β-glucuronidase (GUS), was previously analysed in the T1 generation of 25 independent transformed lines of Lotus corniculatus cv. Leo. In the work reported here, GUS activity in various tissues of seven of these lines was tested in the T2 generation. Four representative lines were chosen for more detailed study in the T3 generation. Lines 25 and 38 had multiple, independently segregating transgene inserts; lines 24 and 39 appeared to transmit one segregating transgene insert to their T1 progeny, although transgene expression was low and was detected in fewer seedlings than expected in line 39. The uidA gene was inherited and expressed in seedlings of T1, T2 and T3 generations of all four lines. In all lines, transgene expression varied between tissues, with more embryos than seedlings
having detectable GUS activity. Studies in the T2 generation showed that use of transgenic plants as female or male parents altered the frequency of expression of the transgene
in progeny. By contrast, in the T3 generation the use of transgenic plants as female or male parents did not effect either frequency of transmission, or expression
of the transgene, in any of the four lines. Transgene inheritance was also similar among individual pods within flower heads
and between individual flower heads.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
64.
Do by‐catch reduction devices in longline fisheries reduce capture of sharks and rays? A global meta‐analysis
下载免费PDF全文
![点击此处可从《Fish and Fisheries》网站下载免费的PDF全文](/ch/ext_images/free.gif)
By‐catch in marine fisheries, particularly those using pelagic and demersal longlines, is a major driver of declines in abundance of sharks and rays around the world. A wide variety of by‐catch reduction devices (BRDs), that is, modified gears designed to reduce incidental captures of a variety of marine species while maintaining target catch rates, have been proposed, but the extent to which BRDs actually reduce the risk of catching sharks and rays remains unclear. We performed a meta‐analysis of 27 publications that reported the capture of sharks and rays and, in some cases, of targeted teleosts in longline gear deployed with and without BRDs. The risk of shark and ray capture differed between types of BRDs, but only one BRD type, longlines raised off the bottom, reduced by‐catch significantly. Circle hooks did not reduce the risk of capturing sharks and rays but might improve discard survival and are inexpensive, which might make them effective in reducing the detrimental effects of longlining on these species. In addition to being generally ineffective, some devices, such as electropositive and magnetic repellents, are expensive and have inherent construction drawbacks that are likely to make them unsuitable for commercial use. Overall, most BRDs did not affect the likelihood of catching targeted teleosts, but a substantial number of studies did not adequately assess target catch. We identified two poorly studied classes of BRD gear (i.e. raised demersal longlines, and monofilament nylon leaders), which represent promising directions for future research. 相似文献
65.
Development and validation of glycoprotein‐based native‐subunit vaccine for fish against Aeromonas hydrophila
下载免费PDF全文
![点击此处可从《Journal of fish diseases》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A Çiftci E E Onuk G Çiftci A Fındık M Ü Söğüt B I Didinen A Aksoy K Üstünakın T Gülhan F Balta S Altun 《Journal of fish diseases》2016,39(8):981-992
Aeromonas hydrophila is known to be causative agent of an infection named as Bacterial haemorrhagic septicaemia or red pest in freshwater fish. The aim of this study was to develop and validate the glycoprotein‐based fish vaccine against Aeromonas hydrophila. For this aim, after identification and characterization of A. hydrophila isolates from fish farms, one A. hydrophila isolate was selected as vaccine strain. Antigenic glycoproteins of this vaccine strain were determined by Western blotting and glycan detection kit. The connection types of these glycoproteins were examined by glycoprotein differentiation kit. Two glycoproteins, molecular weights of 19 and 38 kDa, with SNA connection type were selected for use in vaccination trials. After their purification by SNA‐specific lectin and size‐exclusion chromatography, protection studies with purified proteins were performed. For challenge trials, four experimental fish groups were designated: Group I (with montanide), Group II (with montanide and ginseng), Group III [with Al(OH)3] and Group IV [with Al(OH)3 and ginseng]. The survival ratings of fish were determined, and protection was calculated as 21.56%, 29.41%, 69.83% and 78.88% in groups I, II, III and IV, respectively. In conclusion, A. hydrophila glycoproteins with Al(OH)3 and ginseng could be used as a safe and effective vaccine for fish. 相似文献
66.
67.
Benoît Remenant Geneviève L. Grundmann Lucile Jocteur-Monrozier 《Soil biology & biochemistry》2009,41(1):29-36
Natural structural units of a luvisol under maize crop were studied to assess if soil structure directed sampling could improve the understanding of arrangements of bacteria in spatially constraint location. Three habitats were defined: (i) soil around fine lateral roots (rhizo-aggregates), (ii) soil close to basal roots (core clods) and (iii) unplanted soil between rows (bare soil clods). These habitats were also investigated with maize plants resulting from Azospirillum lipoferum CRT1 inoculated seeds as a model of enhanced fine root system. Rhizo-aggregates were clearly separated from each other (disconnected habitat) in contrast to micro-samples (fragments) from clods, which belong to cohesive macro-structures. Genetic fingerprints on metagenomic extracts were used to characterize the structure of bacterial communities on 95 micro-samples from the three habitats. For eubacteria, automated RISA (Ribosomal Intergenic Spacer Analysis) of ITS (Internal Transcribed Spacer) profiles were performed. PCR-RFLP on nifH gene were used to describe the N-fixer guilds. Exploratory multivariate analyses (PCA and MDS) revealed bacterial community patterns in the sampled habitats. On the basis of ITS profiles, rhizo-aggregates harboured closely related communities, distant from those of the unplanted soil, and each sampled rhizo-aggregate could therefore be considered as a sub-unit of the whole macro-habitat, comprising all the fine roots. The observed low dissimilarity of disconnected rhizo-aggregates is likely to result from the direct influence of maize root tips on the recruitment of rhizosphere bacteria. Molecular fingerprints of nifH from basal root clods (core) were more similar to bare soil than to rhizo-aggregates, indicating similar ecological conditions without, or with, at least, poor maize exudating root influence. Although our study was performed on a limited number of situations, the distribution of bacteria was revealed to be patterned by soil structure units, which is a first step to improve the modelling of microbial ecology in soils. 相似文献
68.
Edita Mazurová Klára Hilscherová Tereza Šídlová-Štěpánková Heinz-R. Köhler Rita Triebskorn Dirk Jungmann John P. Giesy 《Journal of Soils and Sediments》2010,10(3):423-433
Purpose
The aim of the present study was to investigate possible relationships between the sediment contaminants and the occurrence of intersex in situ. Two of the studied sediments were from polluted sites with increased occurrence of intersex crustaceans (Lake Pilnok, black coal mining area in the Czech Republic, inhabited by the crayfish Pontastacus leptodactylus population with 18% of intersex; creek Lockwitzbach in Germany with Gammarus fossarum population with about 7% of intersex). 相似文献69.
Guillermina Dalla-Salda Alejandro Martinez-Meier Hervé Cochard Philippe Rozenberg 《Forest Ecology and Management》2009
Drought response of three Douglas-fir clones (slow, intermediate and fast growing) inhabiting two different climatic regimes in France was examined. We used the hydraulic conductivity and the percent loss of conductivity due to embolism from stems and branches as well as wood microdensity measurements to determine the role of genetics in the control of embolism in this species. Conductivity and tree-ring’s microdensity variables (ring width: RW, mean ring density: MRD, minimum ring density: MID and maximum ring density: MAD) were compared in growth rings in all three clones during a typical year (2002) vs. an extremely dry year (2003). A new method was developed in order to assess axial hydraulic specific conductivity (Ks) within tree rings. The results show that branches are more resistant to embolism than stems, and that there are significant differences in embolism resistance among the clones between the two sites. Ks varied between years, sites and clones but the site exerted the most significant effect. Lartimache (more humid site during 2003) trees showed substantially higher Ks than those inhabiting Chassenoix (strongly affected by the 2003 heat and drought wave site). Wood analysis showed a significant year effect for all ring variables and a significant clone effect for all ring variables except for MAD, while the site effect was significant for MRD and MAD. The existence of a genetic control for the study traits indicates that Douglas-fir populations introduced in France may have a selection potential to face extreme climate events like the 2003 heat and drought wave. 相似文献
70.
Anne Poszwa Bruno Ferry Benoît Pollie Catherine Grimaldi Pierre Charles-Dominique Michel Loubet Etienne Dambrine 《Annals of Forest Science》2009,66(5):512-512