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1.
Peanut (Arachis hypogaea) agglutinin (PNA) is extensively used as tumour marker as it strongly recognises the cancer specific T antigen (Galβ1→3GalNAc-), but not its sialylated version. However, an additional specificity towards Galβ1→4GlcNAc (LacNAc), which is not tumour specific, had been attributed to PNA. For correct interpretation of lectin histochemical results we examined PNA sugar specificity using naturally occurring or semi-synthetic glycoproteins, matrix-immobilised galactosides and lectin-binding tissue glycoproteins, rather than mono- or disaccharides as ligands. Dot-blots, transfer blots or polystyrene plate coatings of the soluble glycoconjugates were probed with horse-radish peroxidase (HRP) conjugates of PNA and other lectins of known specificity. Modifications of PNA-binding glycoproteins, including selective removal of O-linked oligosaccharides and treatment with glycosidases revealed that Galβ1→4GlcNAc (LacNAc) was ineffective while terminal α-linked galactose (TAG) as well as exposed T antigen (Galβ1→3 GalNAc-) was excellent as sugar moiety in glycoproteins for their recognition by PNA. When immobilised, melibiose was superior to lactose in PNA binding. Results were confirmed using TAG-specific human serum anti-α-galactoside antibody. 相似文献
2.
Summary A murine hybridoma (455) was cultured in four different serum free media formulations, and a newborn calf serum supplemented medium was used as a basis of comparison. The serum supplemented medium supports a higher cell growth rate and results in a higher IgG titer. However, the antibody secretion rate on a per cell basis is higher in the serum free media, indicating that serum could be inhibitory to antibody secretion. The results identify the possibility of a least eliminating serum during the monoclonal antibody production phase. 相似文献
3.
It has been cited in the literature on hollow fiber systems that pressure gradients persist, and the transmembrane flux of the hollow fiber system is dependent on the pattern of the pressure gradients. The pattern can be used to its advantage in immobilized enzyme systems. However, with immobilized living cell systems, the pressure gradients lead to a nonuniform environment within the hollow fiber cartridge and not necessarily favorable results. This article provides pertinent pressure-drop data on hollow fiber cartridges which are in flow configurations typical of immobilized cell culture work. The results illuminate operational problems that may arise in the culture of either anchorage dependent or independent cells. Possible solutions with crossflow systems are suggested. 相似文献
4.
Summary Post-mitotic epidermal cells of barley leaves were found to contain, in addition to cortical microtubules (CMTs), distinct arrays of endoplasmic microtubules (EMTs). These encircle nuclei and continuously merge into the CMT arrays that underly the plasmalemma. Detailed three-dimensional reconstruction of both types of MTs during fungal infection showed that profound and very rapid MT rearrangements occurred especially in the case of incompatible (resistant) barley-powdery mildew genotype combination. The most early MT responses, followed by their subsequent complete disintegration, were recorded around nuclei. These events might be relevant for the induction of such nuclear processes as onset of DNA synthesis and nuclear chromatin condensation. Observed pattern of early infection events, as well as less prominent responses in the case of compatible (susceptible) barley-powdery mildew genotype combination, both findings suggest that rapid reorganization of the MT cytoskeleton could be involved in recognition of the fungus by host cells and in the initiation of resistance responses in barley leaves. We hypothesize that the integrity and dynamics of the MT cytoskeleton, especially of its perinuclear part, might participate in control mechanisms involved in activation of resistance genes.Abbreviations CMTs
cortical microtubules
- EMTs
endoplasmic microtubules
- MT
microtubules
- PI
propidium iodide
- SC
sensitive combination
- RC
resistant combination 相似文献
5.
Apical root meristems and segments of root elongation zone were sampled from 4- to 5-day-old Zea mays L. seedlings. The vacuolar ATPase and pyrophosphatase, the tonoplast marker enzymes, and the tonoplast -, -, and -aquaporins were visualized by means of indirect immunofluorescent microscopy with the use of the respective antibodies. Following cell plasmolysis (700 mM mannitol, 2.5 h), the vacuolar ATPase and pyrophosphatase were detected in cell wall pores where plasmodesmata remained detached from the plasmolyzed protoplasts. This finding provides further evidence for existence of the vacuolar symplast in the elongation zone of maize root, which may ensure intercellular continuity of plant tissues. The pulsed NMR method was used to study the self-diffusion of water molecules. The diffusive decay in the root elongation zone was nonexponential, and it was transformed to three exponential terms with characteristic coefficients of self-diffusion; two of these coefficients (D
2 and D
3) characterize the water self-diffusion in the cytoplasmic and vacuolar symplasts of root, respectively. The root apical meristem was also investigated with NMR technique by virtue of paramagnetic doping of the apoplast. This approach allowed selective studying of water diffusion within the symplast compartments. Partial dehydration with PEG-6000, 12 and 20%, for 2.5 h and chemical stressors (ABA and salicylic acid, 0.1 mM, 24 h) were applied to modify water permeability of plasmodesmata and tonoplast aquaporins. The transcellular water permeability increased in the root meristem under the action of all stress factors. In the root elongation zone exposed to partial dehydration, the water exchange in the apoplast became the dominant component. Other stress factors affected water relations in different manners. ABA elevated the water permeability of the vacuolar symplast, in contrast to salicylic acid that decreased water conductance of both the cytoplasmic and vacuolar symplasts. 相似文献
6.
Bharath Balu Chitra Chauhan Steven P Maher Douglas A Shoue Jessica C Kissinger Malcolm J Fraser John H Adams 《BMC microbiology》2009,9(1):83
Background
Much of thePlasmodium falciparumgenome encodes hypothetical proteins with limited homology to other organisms. A lack of robust tools for genetic manipulation of the parasite limits functional analysis of these hypothetical proteins and other aspects of thePlasmodiumgenome. Transposon mutagenesis has been used widely to identify gene functions in many organisms and would be extremely valuable for functional analysis of thePlasmodiumgenome. 相似文献7.
Maize callus cells possess numerous protein bodies which develop as sub-compartments of the endoplasmic reticulum. We localized
maize calreticulin mRNAs and protein in maize callus cells using in situ hybridization and immunocytochemistry. Calreticulin
mRNAs were selectively targeted to the endoplasmic reticulum (ER) subdomains surrounding protein bodies. Profilin mRNAs, used
as a positive control for in situ hybridization experiments, showed distinct and rather diffuse localization pattern. Using
both, immunofluorescence and immunogold electron microscopy localization techniques, calreticulin was found to be enriched
around and within protein bodies in maize callus storage cells. As a positive control for reticuloplasmins, HDEL antibody
revealed labelling of protein bodies and of the nuclear envelope. The identity of protein bodies was confirmed by specific
binding of an α zein antibody. These data suggest that calreticulin mRNA is targeted towards protein body forming subdomains
of the ER, and that calreticulin is localized and enriched in these protein bodies. The possibility that calreticulin plays
an important role in zein retention within the ER and/or its assembly and packaging into protein bodies during protein body
biogenesis in maize callus is discussed. 相似文献
8.
9.
Oculocutaneous albinism type 1A (OCA1A) is the most severe form of albinism characterized by a complete lack of melanin production throughout life and is caused by mutations in the TYR gene. TYR gene codes tyrosinase protein to its relation with melanin formation by knowing the function of these SNPs. Based on the computational approaches, we have analyzed the genetic variations that could change the functional behaviour by altering the structural arrangement in TYR protein which is responsible for OCA1A. Consequences of mutation on TYR structure were observed by analyzing the flexibility behaviour of native and mutant tyrosinase protein. Mutations T373K, N371Y, M370T and P313R were suggested as high deleterious effect on TYR protein and it is responsible for OCA1A which were also endorsed with previous in vivo experimental studies. Based on the quantitative assessment and flexibility analysis of OCA1A variants, T373K showed the most deleterious effect. Our analysis determines that certain mutations can affect the dynamic properties of protein and can lead to disease conditions. This study provides a significant insight into the underlying molecular mechanism involved in albinism associated with OCA1A. 相似文献
10.
Plants are complex living beings, extremely sensitive to environmental factors, continuously adapting to the ever changing environment. Emerging research document that plants sense, memorize, and process experiences and use this information for their adaptive behavior and evolution. As any other living and evolving systems, plants act as knowledge accumulating systems. Neuronal informational systems are behind this concept of organisms as knowledge accumulating systems because they allow the most rapid and efficient adaptive responses to changes in environment. Therefore, it should not be surprising that neuronal computation is not limited to animal brains but is used also by bacteria and plants. The journal, Plant Signaling & Behavior, was launched as a platform for exchanging information and fostering research on plant neurobiology in order to allow our understanding of plants in their whole integrated, communicative, and behavioral complexity.
I always go by official statistics because they are very carefully compounded and, even if they are false, we have no others …∼ Jaroslav Hašek, 1911Key Words: plant neurobiology, sensory biology, behavior, biological complexity, evolution, signal integrationThis quotation of writer and mystificator Jaroslav Hašek is from his electorial speech aimed to get a seat in the Austro-Hungarian parliament for his imaginary political party ‘Moderate Progress within the Limits of the Law’ in 1911. It indicates how statistics can be misused for manipulation of public opinion, sometimes allegedly for general good. This quotation is partially relevant also for recent biology which is passing through a critical cross-road from reductionist-mechanistic concepts and methodologies towards the post-genomic, holistic, systems-based analysis of integrated and communicative hierarchic networks known as life processes.There is a message hidden in this Hašek''s aphorism. All those mathematical models, scientific theories and concepts, however appealing, harmonious and long-standing … but which do not correspond to reality …; inevitably will be ‘killed by ugly’ facts generated by scientific progress, and finally replaced by new models, theories, and concepts.1Despite the indisputable success of the reductionistic approach in providing many discoveries regarding single cells and their components, it is increasingly clear that promises of ‘mechanistic’ genocentric biology were just chimeras and that living organisms are much more complex than the sum of their constituents. Ernst Mayr, in his final opus, almost a testament published at his age of 100, strongly opposed the belief that the reductionism at the molecular level could help to explain the complexity of life. He stressed that the concept of biological “emergence”, which deals with the occurrence of unexpected features in complex living systems, is not fully accessible using only physical and chemical approaches.2Themes of hierarchy, continuity, and order dominated biology before the turn of the century, but these have in many cases been replaced by images of the workshop. Examples include such terms as ‘machineries’, ‘mechanistic understanding’, ‘mechanistic explanation’, ‘motors’, ‘machines’, ‘clocks’ etc. This shift may well reflect the characteristic style of our age. These concepts, although useful for mining of details, do not reveal the true complexity of life and can be misleading. Even a one-celled organism is made up of ‘millions’ of subcellular parts. Concerning the great complexity of unicellular creatures Ilya Prigogine (1973) wrote: “… but let us have no illusions, our research would still leave us quite unable to grasp the extreme complexity of the simplest of organism.”3 Moreover, eukaryotic cell proved to be, in fact, ‘cells within cell’,4–8 while there are numerous supracellular situations, the most dramatic one is represented by plants when all cells are interconnected via plasmodesmata into supracellular organism.6 All this collectively indicate that the currently valid ‘Cell Theory’ dogma is approaching its replacement with a new updated concept of a basic unit of eukaryotic life.6–8All those mathematical models, scientific theories and concepts, however appealing, harmonious and long-standing … but which do not correspond to reality …; inevitably will be ‘killed by ugly’ facts generated by scientific progress, and finally replaced by new models, theories, and concepts.Furthermore, genomes are much more complex and dynamic as we ever anticipated.9,10 They often have as much as 99% of non-coding DNA sequences,11 which is not ‘junk DNA’ but rather DNA which is part of multitask networks integrating coding DNA.12 In genomes exposed to stress (like mutations), changes are scored preferentially in non-coding sequences which regain a new balance by complex changes in genome composition and activity.9,10,13,14 There are several definitions regarding what is gene11 and molecular biologists and genetics are learning to be careful not to make strong conclusions from under-expression, knocking-out, or overexpression of any particular gene. It is increasingly clear that mutations in single genes are accompanied with altered expressions of other genes and non-coding DNA sequences too, and even subtle re-arrangements of chromatin structure and genome architecture are possible. The dynamic genome actively regains the lost balance, also via extensive re-shufflings of non-coding DNA.After complete sequencing of numerous genomes, it is clear that our understanding of what constitutes life and what distinguishes living biological systems from non-living chemical - biochemical systems is not much better than our understanding before the start of the genomics era some 60 years ago. Yet, it is also obvious that living systems, whether single cells or whole complex organisms like animals and plants, are not machines and automata which respond to external signals via a limited set of predefined responses and automatic reflexes. While humans and other animals, even insects, are already out of this ‘mechanistic’ trap15,16 which can be traced back to Descartes,17 plants are still considered to act only in predetermined automatic fashions, as mechanical devices devoid of any possibility for choice and planning of their activities. In contrast to machines, life systems are based on wet chemistry, being systems of hierarchical and dynamic integration, communication and emergence.1,18Recently, a critical mass of data has accumulated demanding reconsideration of this mechanistic view of plants.19,20 Plants are complex living beings, extremely sensitive to environmental factors and continuously adapting to the ever changing environment.21 In addition, plants respond to environmental stimuli as integrated organisms. Often, plants make important decisions, such as onset or breakage of dormancy and onset of flowering, which implicate some central or decentralized command center. Moreover, roots and shoots act in an integrated manner allowing dynamic balance of above-ground and below-ground organs. The journal, Plant Signaling & Behavior, was launched as a platform for exchange of information about the integration of discrete processes, including subcellular signalling integrated with higher-level processes. Signal integration and communication results in adaptive behavior of whole supracellular organisms, encompassing also complex, and still elusive, plant-plant, plant-insect, and plant-animal communications. Coordinated behavior based on sensory perception is inherent for neurobiological systems.22 Therefore, plants can be considered for neuronal individuals. Moreover, plants are also able to share knowledge perceived from environment with other plants, communicating both private and public messages.23,24 This implicates social learning and behavioral inheritance in plants too.After complete sequencing of numerous genomes, it is clear that our understanding of what constitutes life and what distinguishes living biological systems from non-living chemical - biochemical systems is not much better than our understanding before the start of genomics era some 60 years ago.
Behavior
- An activity of a defined organism: observable activity when measurable in terms of quantitative effects of the environment whether arising from internal or external stimuli.
- Anything that an organism does that involves action and response to stimulation.