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161.
Summary The use of the anti-pectin monoclonal antibody JIM5 in conjunction with immunofluorescence microscopy and also confocal microscopy has indicated that the JIM5 epitope is associated with structural features of the plasma-membrane-face of the cell wall of tomato pericarp cells. JIM5 recognized the primary pit fields of the cell walls, as identified by co-staining with callose-reactive aniline blue. In addition, abundant linear arrays of the pectin epitope were observed to radiate out from the primary pit fields in parallel, as well as random, arrangements. These observations have implications for our understanding of the organization of the polymer networks that comprise the primary cell wall. 相似文献
162.
Samuel Cirés Lars W?rmer Andreas Ballot Ramsy Agha Claudia Wiedner David Velázquez María Cristina Casero Antonio Quesada 《Applied and environmental microbiology》2014,80(4):1359-1370
Planktonic Nostocales cyanobacteria represent a challenge for microbiological research because of the wide range of cyanotoxins that they synthesize and their invasive behavior, which is presumably enhanced by global warming. To gain insight into the phylogeography of potentially toxic Nostocales from Mediterranean Europe, 31 strains of Anabaena (Anabaena crassa, A. lemmermannii, A. mendotae, and A. planctonica), Aphanizomenon (Aphanizomenon gracile, A. ovalisporum), and Cylindrospermopsis raciborskii were isolated from 14 freshwater bodies in Spain and polyphasically analyzed for their phylogeography, cyanotoxin production, and the presence of cyanotoxin biosynthesis genes. The potent cytotoxin cylindrospermopsin (CYN) was produced by all 6 Aphanizomenon ovalisporum strains at high levels (5.7 to 9.1 μg CYN mg−1 [dry weight]) with low variation between strains (1.5 to 3.9-fold) and a marked extracellular release (19 to 41% dissolved CYN) during exponential growth. Paralytic shellfish poisoning (PSP) neurotoxins (saxitoxin, neosaxitoxin, and decarbamoylsaxitoxin) were detected in 2 Aphanizomenon gracile strains, both containing the sxtA gene. This gene was also amplified in non-PSP toxin-producing Aphanizomenon gracile and Aphanizomenon ovalisporum. Phylogenetic analyses supported the species identification and confirmed the high similarity of Spanish Anabaena and Aphanizomenon strains with other European strains. In contrast, Cylindrospermopsis raciborskii from Spain grouped together with American strains and was clearly separate from the rest of the European strains, raising questions about the current assumptions of the phylogeography and spreading routes of C. raciborskii. The present study confirms that the nostocalean genus Aphanizomenon is a major source of CYN and PSP toxins in Europe and demonstrates the presence of the sxtA gene in CYN-producing Aphanizomenon ovalisporum. 相似文献
163.
The complete mitochondrial DNA sequence of the shark Mustelus manazo: evaluating rooting contradictions to living bony vertebrates 总被引:5,自引:0,他引:5
A remarkable example of a misleading mitochondrial protein tree is
presented, involving ray-finned fishes, coelacanths, lungfishes, and
tetrapods, with sea lampreys as an outgroup. In previous molecular
phylogenetic studies on the origin of tetrapods, ray-finned fishes have
been assumed as an outgroup to the tetrapod/lungfish/coelacanth clade, an
assumption supported by morphological evidence. Standard methods of
molecular phylogenetics applied to the protein-encoding genes of
mitochondria, however, give a bizarre tree in which lamprey groups with
lungfish and, therefore, ray-finned fishes are not the outgroup to a
tetrapod/lungfish/coelacanth clade. All of the dozens of published
phylogenetic methods, including every possible modification to maximum
likelihood known to us (such as inclusion of site heterogeneity and
exclusion of potentially misleading hydrophobic amino acids), fail to place
the ray-finned fishes in a biologically acceptable position. A likely cause
of this failure may be the use of an inappropriate outgroup. Accordingly,
we have determined the complete mitochondrial DNA sequence from the shark,
Mustelus manazo, which we have used as an alternative and more proximal
outgroup than the lamprey. Using sharks as the outgroup, lungfish appear to
be the closest living relative of tetrapods, although the possibility of a
lungfish/coelacanth clade being the sister group of tetrapods cannot be
excluded.
相似文献
164.
165.
Y Wang W Devereux T M Stewart R A Casero 《The Journal of biological chemistry》1999,274(31):22095-22101
166.
P. G. Lloret A. Pulgarín I. Casimiro M. Molina P. J. Casero 《Plant biology (Stuttgart, Germany)》1998,111(1):55-61
Lateral roots in Allium cepa arise in longitudinal rows opposite the protoxylem poles of adventitious roots. The number, spacing within ranks and positional relationship to laterals in different ranks were analysed in control roots and those treated with an auxin (α-naphthaleneacetic acid). Treatment increased numbers of laterals per rank and distributed the more evenly in all ranks. Laterals of control roots were concentrated in two neighbouring ranks. Auxin-treated roots showed a more regular distribution of laterals between ranks and close spacing of laterals along each rank. Comparisons with theoretical random distributions suggest a dispersed spacing model for lateral root arrangement with mutual repulsion between successive lateral roots within each rank both in control and auxintreated roots. On the other hand, there is some interaction between laterals in different ranks in 0.1 mM NAA-treated roots. 相似文献
167.
168.
Decomposable graphical Gaussian model determination 总被引:8,自引:0,他引:8