全文获取类型
收费全文 | 390篇 |
免费 | 20篇 |
专业分类
林业 | 25篇 |
农学 | 12篇 |
93篇 | |
综合类 | 50篇 |
农作物 | 27篇 |
水产渔业 | 37篇 |
畜牧兽医 | 128篇 |
园艺 | 13篇 |
植物保护 | 25篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 18篇 |
2020年 | 21篇 |
2019年 | 16篇 |
2018年 | 10篇 |
2017年 | 17篇 |
2016年 | 27篇 |
2015年 | 16篇 |
2014年 | 14篇 |
2013年 | 11篇 |
2012年 | 35篇 |
2011年 | 42篇 |
2010年 | 15篇 |
2009年 | 21篇 |
2008年 | 18篇 |
2007年 | 24篇 |
2006年 | 17篇 |
2005年 | 16篇 |
2004年 | 22篇 |
2003年 | 10篇 |
2002年 | 16篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有410条查询结果,搜索用时 15 毫秒
51.
Ballabio C Magni C Restani P Mottini M Fiocchi A Tedeschi G Duranti M 《Plant foods for human nutrition (Dordrecht, Netherlands)》2010,65(4):396-402
The immunological cross-reactivity among major protein- and oil-crops, including lupin, lentil, pea, peanut, kidney bean and
soybean, has been studied by a combination of in vitro and in vivo experimental approaches: SDS-PAGE separations of legume protein extracts and immuno-blot revelations with 12 peanut-sensitive
subjects’ sera, Immuno-CAP and Skin Prick tests on the same subjects. The immuno-blotting data showed a wide range of IgE-binding
responses both displayed by one subject towards different plant extracts and among subjects. Differences were both quantitative
and qualitative. The prevalent responses of most subjects’ sera were seen with peanut polypeptides, as expected, as well as
with various polypeptides of the other legumes, the most recurrent of which were the basic subunits of the 11S globulins.
The distribution of in vivo responses generally paralleled those obtained by in vitro approaches with strong responses elicited by peanut, lentil and pea protein extracts, especially by most sensitive subjects,
thus providing a consistent overall set of results. In this work, the comparison of various approaches has allowed us to get
an overall broad picture of the immunological cross-reactivities among proteins of widely used different seed species and
to hypothesize the role of most conserved specific polypeptides. 相似文献
52.
Alessandro Bonanno 《Agriculture and Human Values》1988,5(1-2):92-100
This study investigates the socio-historical relationships existing between the development of the agricultural structure and the process of technical development. Adopting a political economy posture, it is argued that the development of technical procedures in agriculture has been aimed historically at the maximization of production and productivity. This phenomenon has been generated by the social hegemony of groups interested in the enhancement of accumulation of capital and has been translated into an emphasis on large productive units, which discriminates against small and medium farms. This pattern of development has been legitimized through a social consensus which involves an emphasis on small family producers. This contradiction is embodied in the generation of a dualistic agricultural structure characterized by the prosperity of large farms, the persistence of small farms and the crisis of medium farms and in patterns of overproduction and unavailability of food for the poor segments of society. 相似文献
53.
Paolo Fantozzi Alessandro Sensidoni 《Plant foods for human nutrition (Dordrecht, Netherlands)》1983,32(3-4):351-368
The goals of the present studies were: (1) to obtain smoking material from tobacco with reduced toxicity; (2) to use the tobacco leaf, as an alternative to other plants, as a source of food protein. On the grounds of technological, nutritional and agronomical results, the following observations can be made: (1) It is feasible to lower the toxicity of the tobacco smoke by extracting protein from the green leaves before curing. (2) The cured deproteinized tobacco can easily be utilized for the production of smoking material without any important alteration of its taste. (3) The composition of the tobacco protein concentrate is very interesting and is superior to other protein concentrates. (4) Itsin vivo andin vitro digestibility is one of the highest among the vegetable protein sources which have been studied. (5) Use of high planting densities and high levels of nitrogen fertilization per hectare results in high yields of total protein from tobacco (1794 Kg/ha). 相似文献
54.
After a period of deflation during the 1991-1993 flank eruption, Mount Etna underwent a rapid inflation. Seismicity and ground deformation show that since 1994, a huge volume of magma intruded beneath the volcano, producing from 1998 onward a series of eruptions at the summit and on the flank of the volcano. The last of these, started on 27 October 2002, is still in progress and can be considered one of the most explosive eruptions of the volcano in recent times. Here we show how geodetic data and seismic deformation, between 1994 and 2001, indicate a radial compression around an axial intrusion, consistent with a repressurization of Mount Etna's plumbing system at a depth of 6 to 15 kilometers, which triggered most of the seismicity and provoked the dilatation of the volcano and the recent explosive eruptive activity. 相似文献
55.
Olivieri A Achilli A Pala M Battaglia V Fornarino S Al-Zahery N Scozzari R Cruciani F Behar DM Dugoujon JM Coudray C Santachiara-Benerecetti AS Semino O Bandelt HJ Torroni A 《Science (New York, N.Y.)》2006,314(5806):1767-1770
Sequencing of 81 entire human mitochondrial DNAs (mtDNAs) belonging to haplogroups M1 and U6 reveals that these predominantly North African clades arose in southwestern Asia and moved together to Africa about 40,000 to 45,000 years ago. Their arrival temporally overlaps with the event(s) that led to the peopling of Europe by modern humans and was most likely the result of the same change in climate conditions that allowed humans to enter the Levant, opening the way to the colonization of both Europe and North Africa. Thus, the early Upper Palaeolithic population(s) carrying M1 and U6 did not return to Africa along the southern coastal route of the "out of Africa" exit, but from the Mediterranean area; and the North African Dabban and European Aurignacian industries derived from a common Levantine source. 相似文献
56.
Cocchi M Franchini G Manzini D Manfredini M Marchetti A Ulrici A 《Journal of agricultural and food chemistry》2004,52(13):4047-4056
A comparison of different digestion procedures has been carried out for the analysis of metal concentration in samples of vinegars and Aceto Balsamico Tradizionale of Modena (ABTM) coming from an unique barrel set. In particular, classical wet, dry ashing, and closed vessel microwave digestion procedure have been utilized and compared for each investigated species. In a few cases, direct metal determination on ABTM (without treatment procedure) is proposed as possible alternative to sample manipulation. Flame atomic absorption spectrometry was used for the quantification of iron and zinc, while graphite furnace atomic absorption spectrometry was used for all the other elements (i.e., chromium, manganese, cobalt, nickel, copper, cadmium, and lead). The comparison among the different sample treatments was carried out by the use of statistical and chemometric tools. In particular, principal component analysis and ANOVA approaches were used to discriminate between the diverse analytical methods. Furthermore, for all the dissolving techniques, the analytical metal recovery was always evaluated by the application of the recovery function on the same sample matrix. In general, the recoveries were fairly good, ranging from 90 to 103%, except for Cd and Pb with dry ashing, which showed recovery values close to 55% and 67%, respectively. As regards the metals concentration of the investigated samples, the experimental data reveal for some species the presence of concentration slightly over the legal limit fixed for wine and wine vinegar. 相似文献
57.
Iacopo Vannozzi Matteo Tesi Marta Zangheri Viola Maria Innocenti Alessandra Rota Simonetta Citi Alessandro Poli 《Veterinary research communications》2018,42(2):137-143
Ultrasonography is a valuable tool for the evaluation of neoplastic lesions in the dog and there is a growing interest in the use of this technique for the stadiation of canine mammary tumours. An accurate assessment of small sized nodules facilitates the stadiation of the mammary lesions and helps the clinician in the choice of the most indicated surgical therapy. The aim of this study was to identify those ultrasound criteria that may be useful in discriminating between benign and malignant lesions of small size (diameter smaller than 2 cm). Sixty-two nodules, < 2 cm in larger diameter, belonging to thirty-five bitches presented between January 2012 and February 2014 were evaluated. Tumours were observed by conventional ultrasound and assessed for: shape (regular-irregular), limit (defined-ill-defined), margins (regular-irregular), echogenicity (hypoechoic-isoechoic-hyperecoic), echotexture (homogeneus-heterogeneus), presence of hyperecoic halo, distal acoustic enhancement or shadowing and surrounding tissue alterations. Among the alterations in surrounding tissues, the disruption of the glandular tissue and the increase in echogenicity of the peritumoral tissues were assessed. Thereafter, bitches were subjected to mastectomy and nodules were evaluated histologically. None of the ultasound criteria considered in the current study showed a statistically significant relation with malignancy, except for the presence of alterations in the tissue surrounding the nodules. According to our results, this characteristic may indicate malignancy, however its subjectivity may affect the applicability in clinical practice. In conclusions, conventional ultrasound in bitches had a limited ability in discriminating benign and malignant mammary gland neoplastic lesions of small size (diameter?<?2 cm). 相似文献
58.
Aiuti A Slavin S Aker M Ficara F Deola S Mortellaro A Morecki S Andolfi G Tabucchi A Carlucci F Marinello E Cattaneo F Vai S Servida P Miniero R Roncarolo MG Bordignon C 《Science (New York, N.Y.)》2002,296(5577):2410-2413
Hematopoietic stem cell (HSC) gene therapy for adenosine deaminase (ADA)-deficient severe combined immunodeficiency (SCID) has shown limited clinical efficacy because of the small proportion of engrafted genetically corrected HSCs. We describe an improved protocol for gene transfer into HSCs associated with nonmyeloablative conditioning. This protocol was used in two patients for whom enzyme replacement therapy was not available, which allowed the effect of gene therapy alone to be evaluated. Sustained engraftment of engineered HSCs with differentiation into multiple lineages resulted in increased lymphocyte counts, improved immune functions (including antigen-specific responses), and lower toxic metabolites. Both patients are currently at home and clinically well, with normal growth and development. These results indicate the safety and efficacy of HSC gene therapy combined with nonmyeloablative conditioning for the treatment of SCID. 相似文献
59.
da Silva Andrade G Bruhn FR Rocha CM Guimarães Ade S Gouveia AM Guimarães AM 《Veterinary parasitology》2012,188(1-2):168-171
The aim of this study was to determine the prevalence and risk factors associated with infection due to Neospora caninum in serum samples from 488 sheep originating from 63 farms in 63 municipalities distributed across eight of the twelve mesoregions of the state Minas Gerais, southeastern Brazil. For detection of N. caninum the sheep serum samples were subjected to the indirect fluorescence antibody test (IFAT ≥ 50). To identify the risk factors associated with infection due to N. caninum a questionnaire was filled out for each herd by interviewing, the individual responsible for the herd, demanding information on the general characteristics of the property. Sixty-four sheep sera (13.1%; 95% CI=10.3-16.4) presented IgG-specific anti-N. caninum antibodies with the following titers: 50 (49; 76.6%), 100 (7; 10.9%), 200 (4; 6.2%), 400 (3; 4.7%) and 800 (1; 1.6%). The prevalence of infected sheep per mesoregion ranged from 0 to 28.1%. Out of the 63 farms sampled, 31 (49.2%; 95% CI=36.4-62.1) presented at least one seropositive sheep. No significant association was found between the presence of anti-N. caninum antibodies and the risk factors evaluated on the farms, except for the mesoregion variable (p=0.004; OR=0.429; CI95%=0.182-1.008). These results indicate that there is a need for additional research to define the epidemiological importance of this parasite as a cause of reproductive problems in sheep herds in Minas Gerais. 相似文献
60.
Much current experimental research on transport in molecular junctions focuses on finite voltages, where substantial polarization-induced nonlinearities may result in technologically relevant device-type responses. Because molecules have strong polarization responses to changing charge state or external field, molecules isolated between electrodes can show strongly nonlinear current-voltage responses. For small applied voltages (up to approximately 0.3 volt), weak interaction between transporting electrons and molecular vibrations provides the basis for inelastic electron tunneling spectroscopy. At higher voltages and for certain time scale regimes, strong coupling effects occur, including Coulomb blockade, negative differential resistance, dynamical switching and switching noise, current hysteresis, heating, and chemical reactions. We discuss a general picture for such phenomena that arise from charging, strong correlation, and polarization (electronic and vibrational) effects in the molecule and at the interface. 相似文献