全文获取类型
收费全文 | 103篇 |
免费 | 0篇 |
专业分类
103篇 |
出版年
2019年 | 1篇 |
2016年 | 1篇 |
2014年 | 3篇 |
2013年 | 5篇 |
2012年 | 6篇 |
2011年 | 8篇 |
2010年 | 6篇 |
2009年 | 5篇 |
2008年 | 10篇 |
2007年 | 10篇 |
2006年 | 3篇 |
2005年 | 6篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 1篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1998年 | 1篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1983年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1959年 | 2篇 |
1958年 | 3篇 |
排序方式: 共有103条查询结果,搜索用时 15 毫秒
71.
Using morphological and biochemical criteria, comparisons weremade between intact and excised roots of normal tomato (Lycopersiconesculentum Mill.) and the reduced form of the homozygous lanceolatemutant. Intact normal roots showed greater growth as reflectedin length of the main root axis, number of lateral roots, andprotodermal cell size. Excised normal roots grew more rapidlythan those of the mutant only during the first 24-h intervalof the first week in culture. Intact mutant roots revealed agreater activity of peroxidase, but excised mutant roots showedno increase in enzyme activity. It is concluded that the primarysite of action of the mutant allele is the shoot system, andin particular the leaf marginal meristem. The effects of thelanceolate gene on the root system in tomato are interpretedas being of secondary importance with regard to gene action. 相似文献
72.
BRANCO-PRICE CRISTINA; KAWAGUCHI RIKI; FERREIRA RICARDO B.; BAILEY-SERRES JULIA 《Annals of botany》2005,96(6):1142
Annals of Botany 96: 647660, 2005 Unfortunately, there were errors in Figure 5 of this article.The 相似文献
73.
SARAH J. ADAMOWICZ PAUL D. N. HEBERT MARÍA CRISTINA MARINONE 《Zoological Journal of the Linnean Society》2004,140(2):171-205
Although the temperate regions of South America are known to have a diverse daphniid fauna, there has been no genetic evaluation of the existing taxonomic system or of the affinities between the North and South American faunas. The present study analyses mitochondrial DNA sequences and allozyme variation to investigate species diversity in 176 Daphnia populations from Argentina. This work established the presence of at least 15 species in Argentina, six of which are either undescribed or are currently misidentified and two of which represent range extensions of North American taxa. Eleven of the Argentine species appear endemic to South America, while the remaining four also occur in North America. In the latter cases, the close genetic similarity between populations from North and South America indicates the recent exchange of propagules between the continents. While biological interactions and habitat availability have undoubtedly contributed to the observed species distributions, chance dispersal has apparently played a dominant role in structuring large-scale biogeographical patterns in this genus and probably in other passively-dispersed organisms. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society , 2004, 140 , 171−205. 相似文献
74.
Specific and Common Epitopes in Mating Pheromones of Euplotes raikovi Revealed by Monoclonal Antibodies 总被引:1,自引:0,他引:1
PIER LUIGI FIORI CRISTINA MICELI SIMONA RAFFIONI ADRIANA VALLESI 《The Journal of eukaryotic microbiology》1990,37(3):187-190
Polypeptide mating pheromones Er-1 and Er-2, purified from the supernatant of Euplotes raikovi cultures of mating type I and mating type II, respectively, were used to immunize mice and obtain monoclonal antibodies. Five hybridoma clones producing antibodies specific to the mating pheromones were selected. They were analyzed for immunospecificity by immunoperoxidase assay, immunoblotting, and for their efficacy in inhibition of mating pheromone activity. Monoclonal antibodies from two hybridoma clones recognized only the mating pheromone used as antigen; those from the other three clones reacted, to comparable extents, with both mating pheromones. On the basis of these results it was assumed that two immunogenic sites exist in Er-1 and Er-2, one specific and the other common to both mating pheromones. 相似文献
75.
SERGIO CASTELLANO CRISTINA GIACOMA TATJANA DUJSEBAYEVA 《Biological journal of the Linnean Society. Linnean Society of London》2000,70(2):341-360
We describe the spatial pattern of variation of morphometric characters and call acoustic properties of tetraploid green toads [Bufo viridis complex) from eight populations in Central Asia, and we analyse the causal agents responsible for the patterns observed, by means of partial Mantel tests. Populations significantly differ with respect to both body size and body shape. Since animals inhabiting the driest regions are smaller, but not younger, man animals from less dry areas, we suggest that their small body size is due to the limiting effect of arid climate on growth rate. Differences in body shape are positively associated only with geographic distances, and we suggest that isolation by distance might have played an important role in determining the pattern of variation. Populations significantly differ also with respect to the acoustic properties of the call, in particular, with respect to temperature-adjusted pulse rate and body size-adjusted fundamental frequency; that is, with respect to those properties which are under the strongest morphological or physiological constraints, and that show the lowest variability within individuals (static properties). The pattern of variation of calls shows positive association with geographic distances, but not with climatic distances. Calls do vary, and in this region the main causal agent responsible for call variation might have been the isolation by distance. The evolutionary implications of these results are discussed. 相似文献
76.
JORGE RABINOVICH SILVIA PIETROKOVSKY CRISTINA WISNIVESKY-COLLI 《Physiological Entomology》2006,31(4):361-370
Abstract. Eggs laid in the laboratory by T. guasayana (Wygodzinsky & Abalos 1949) adults collected from wild biotopes in Santiago del Estero (Argentina) were exposed to fluctuating temperatures, and 172 egg batches, involving 1574 eggs, completed development. Their development times were fitted to the linear degree-day model and three nonlinear models ( devar , Lactin, and Rueda). Parameter values and 95% CL were estimated. The lower development threshold is estimated to be 15 °C (linear devar model) and 17.5 °C (Lactin model), and the temperature resulting in the shortest development time is estimated to be between 26 °C (Lactin model) and 37 °C (nonlinear devar model). The thermal death point by the Lactin model is 34.4 °C, and conforms well with other studies. Differences between the present results and those of other studies for T. guasayana are discussed in terms of the maternal effects, the influence of experimental conditions, and the rate summation effect. Using the climatic conditions of the natural environment of T. guasayana , the results are interpreted in terms of physiological adaptation. A generalized development rate response of T. guasayana eggs to increasing temperature is proposed, with three ranges: between 10 and 14.8 °C development rate increases in an accelerating way; between 14.8 and 29.2 °C development rate increases more or less linearly, and between 29.2 and 34 °C development rate decreases. 相似文献
77.
CRISTINA SCHETINO BASTOS JOAO CARLOS CARDOSO GALVAO MARCELO COUTINHO PICANCO PAULO ROBERTO GOMES PEREIRA PAULO ROBERTO CECON 《Insect Science》2007,14(2):117-123
This work aims to study the effect of the nutrient contents in the leaves of corn on the incidence of Spodopterafrugiperda (Smith) (Lepidoptera: Noctuidae) and Dalbulus maidis (Delong & Wolcott) (Homoptera: Cicadellidae). The treatments were represented by unfertilized corn plants and corn plants fertilized with 250 kg of the formulation 4-14-8 (N- P-K) + 100 kg of ammonium sulfate (AS)/ha and 500 kg of the formulation 4-14-8 (N-P-K) +200 kg of AS/ha, arranged in randomized blocks with four replicates. Attacks by S. frugiperda and D. maidis were higher as the nitrogen, sulfur, calcium and copper content in the leaves of corn increased. The effects of calcium and copper found in this study were not consistent with that of lower susceptibility associated with higher levels of these nutrients mentioned in the literature. We believe that there was a cumulative effect of the nutrients altogether, building up a nutritiously better vegetable which in turn had less reserve for defense, or that the content of both nutrients in the leaves were not high enough to induce such effects. 相似文献
78.
GABRIELA OTERO CAROLINE AGORIO ALEXANDRA SUJANOV LOURDES ECHARTE ANA TCHEKMEDYIAN MONICA MONTELONGO ALBA MENYOU ANDRES RODRIGUEZ LILIAN DIAZ ISMAEL RODRIGUEZ CRISTINA TOURIÑO 《Cytotherapy》2019,21(2):189-199
Background
Chronic venous leg ulcers (VLUs) are a common problem in clinical practice and available treatments are not satisfactory. The use of adjuvant therapies in combination with lower limb compression may lead to improved healing rates. Chronic wounds are candidates for new strategies in the emergent field of regenerative medicine. Bone marrow–derived cells (BMDCs) contain cells and secrete cytokines known to participate in wound healing. Thus, BMDC therapy seems a logical strategy for the treatment of chronic wounds. Our objective was to evaluate feasibility, safety and initial clinical outcome of autologous BMDC therapy associated with standard treatment in patients with VLUs.Methods
We conducted an open-label, single-arm, prospective pilot clinical trial in four patients with six chronic VLUs. The study protocol was approved by the institutional and national review boards and ethics committees. Bone marrow was harvest, processed and then administered by multiple injections into the ulcers. All patients received standard treatment and non-healing characteristics of the VLUs were confirmed at study entry.Results
Ulcer size and wound pain evaluated 12 months after BMDC treatment were significantly reduced (P < 0.05). BMDC treatment was safe and well tolerated in long-term follow-up.Discussion
Despite the low number of patients studied, our results showed that autologous BMDC treatment could be a useful, feasible and safe procedure to enhance ulcer healing. However, randomized controlled trials with more patients are needed to address this question and translate this approach into clinical practice. 相似文献79.
CLAUDIA M. D'AVILA-LEVY ALINE C. C. VOLOTÃO FERNANDA M. ARAÚJO JOSÉ B. DE JESUS MARIA CRISTINA M. MOTTA ALANE B. VERMELHO RÉ L. S. SANTOS MARTA H. BRANQUINHA 《The Journal of eukaryotic microbiology》2009,56(5):454-458
ABSTRACT. We report the characterization of cell-associated and extracellular peptidases of Bodo sp., a free-living flagellate of the Bodonidae family, order Kinetoplastida, which is considered ancestral to the trypanosomatids. This bodonid isolate is phylogenetically related to Bodo caudatus and Bodo curvifilus . The proteolytic activity profiles of Bodo sp. were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis containing co-polymerized gelatin, casein, hemoglobin, or bovine serum albumin as substrates. The enzymatic complex degraded gelatin better in acidic pH, and under these conditions four proteolytic bands (120, 100, 90, and 75 kDa) were detected in the cellular or extracellular extracts. Two peptidases (250 and 200 kDa) were exclusively detected with the substrate casein. All these enzymes belong to the serine peptidase class, based on inhibition by aprotinin and phenylmethylsulfonyl fluoride. This is the first biochemical characterization of peptidases in a free-living Bodo sp., potentially providing insight into the physiology of these protozoa and the evolutionary importance of peptidases to the order Kinetoplastida as some of these enzymes are important virulence factors in pathogenic trypanosomatids. 相似文献
80.
LUCIANO BULLINI ROSSELLA CIANCHI PAOLA ARDUINO LINO DE BONIS MARIA CRISTINA MOSCO REA VERARDI DANIELE PORRETTA BRUNO CORRIAS WALTER ROSSI 《Biological journal of the Linnean Society. Linnean Society of London》2001,72(2):193-201
The hybrid origin of the western Mediterranean orchid Dactylorhiza insularis was demonstrated by genetic markers. Allozyme data showed that throughout its range D. insularis has an allotriploid constitution and reproduces apomictically. The parental species of D. insularis were identified as D. romana andD. sambucina; they contributed 2 alleles and 1 allele, respectively, at the allozyme loci studied. The maternal species of D. insularis was D. romana , as inferred from cpDNA ( trn L(UAA) intron). High genetic similarities were found when comparing present populations of D. romana and D. sambucina with their respective genomes 'frozen' in D. insularis. Dactylorhiza insularis showed fixed (or nearly fixed) heterozygosity at 11 out of the 19 loci studied, and poor genetic variation: eight multilocus genotypes were detected at allozyme level. No multilocus genotype differs from the most similar one by more than one allele substitution. All D. insularis individuals showed the same cpDNA haplotype (I) , regardless of their geographic origin and multilocus genotype. The I haplotype is similar, but not identical to that found in D. romana (R). No recurrent formation of D. insularis was observed in hybrid zones between D. romana and D. sambucina , where diploid sexual hybrids (F1; Fn , backcrosses) were detected. Available data agree with a single origin for D. insularis , which possibly occurred in the present postglacial, when D. romana and D. sambucina , expanding from their glacial refugia, came into contact. The genetic homogeneity found between D. romana and D. markusii , both from their locus classicus , indicates that the latter is a junior synonym of D. romana; on the other hand, D. romana and D. sambucina are well differentiated species ( DNei = 0.59). 相似文献