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991.
Antifreeze proteins, AFP, impede freezing of bodily fluids and damaging of cellular tissues by low temperatures. Adsorption-inhibition mechanisms have been developed to explain their functioning. Using in silico Molecular Dynamics, we show that type I AFP can also induce melting of the local ice surface. Simulations of antifreeze-positive and antifreeze-negative mutants show a clear correlation between melting induction and antifreeze activity. The presence of local melting adds a function to type I AFPs that is unique to these proteins. It may also explain some apparently conflicting experimental results where binding to ice appears both quasipermanent and reversible. 相似文献
992.
The integration of various types of genomic data into predictive models of biological networks is one of the main challenges currently faced by computational biology. Constraint-based models in particular play a key role in the attempt to obtain a quantitative understanding of cellular metabolism at genome scale. In essence, their goal is to frame the metabolic capabilities of an organism based on minimal assumptions that describe the steady states of the underlying reaction network via suitable stoichiometric constraints, specifically mass balance and energy balance (i.e. thermodynamic feasibility). The implementation of these requirements to generate viable configurations of reaction fluxes and/or to test given flux profiles for thermodynamic feasibility can however prove to be computationally intensive. We propose here a fast and scalable stoichiometry-based method to explore the Gibbs energy landscape of a biochemical network at steady state. The method is applied to the problem of reconstructing the Gibbs energy landscape underlying metabolic activity in the human red blood cell, and to that of identifying and removing thermodynamically infeasible reaction cycles in the Escherichia coli metabolic network (iAF1260). In the former case, we produce consistent predictions for chemical potentials (or log-concentrations) of intracellular metabolites; in the latter, we identify a restricted set of loops (23 in total) in the periplasmic and cytoplasmic core as the origin of thermodynamic infeasibility in a large sample (10(6)) of flux configurations generated randomly and compatibly with the prior information available on reaction reversibility. 相似文献
993.
The hippocampus is one of the only two regions in the adult mammalian brain endowed with life-long neurogenesis. Yet this adult neurogenesis is a challenging process as newborn neurons face several times life-and-death decisions while in the process of stably integrating into a pre-existing network. Here we describe the morphological and physiological changes a young neuron experiences during its first few weeks of life of stepwise integration into the circuit. This process is competitive in nature, with only few of the newly generated neurons being awarded with a grant of survival. Although the underlying mechanisms are far from being understood, evidence suggests that this competition for stable integration and survival amongst cohorts of newborn neurons occurs to large degree on a synaptic level and may involve specific patterns of neural activity. 相似文献
994.
Raimondi MT Raimondi MT Eaton SM Eaton SM Nava MM Nava MM Laganà M Laganà M Cerullo G Cerullo G Osellame R 《Journal of applied biomaterials & functional materials》2012,10(1):e56-e66
Three-dimensional material microstructuring by femtosecond laser-induced two-photon polymerization is emerging as an important tool in biomedicine. During two-photon polymerization, a tightly focused femtosecond laser pulse induces a crosslinking photoreaction in the polymer confined within the focal volume. As a rapid-prototyping technique, two-photon polymerization enables the fabrication of truly arbitrary three-dimensional micro- and nano-structures directly from computer models, with a spatial resolution down to 100 nm. In this review, we discuss the fundamentals, experimental methods, and materials used for two-photon polymerization; in addition, we present some applications of this technology related to microfluidics and to biomaterial scaffolds for tissue engineering and regenerative medicine. 相似文献
995.
996.
Lucia Maria Sacheli Matteo Candidi Enea Francesco Pavone Emmanuele Tidoni Salvatore Maria Aglioti 《PloS one》2012,7(11)
Prediction of “when” a partner will act and “what” he is going to do is crucial in joint-action contexts. However, studies on face-to-face interactions in which two people have to mutually adjust their movements in time and space are lacking. Moreover, while studies on passive observation have shown that somato-motor simulative processes are disrupted when the observed actor is perceived as an out-group or unfair individual, the impact of interpersonal perception on joint-actions has never been directly addressed. Here we explored this issue by comparing the ability of pairs of participants who did or did not undergo an interpersonal perception manipulation procedure to synchronise their reach-to-grasp movements during: i) a guided interaction, requiring pure temporal reciprocal coordination, and ii) a free interaction, requiring both time and space adjustments. Behavioural results demonstrate that while in neutral situations free and guided interactions are equally challenging for participants, a negative interpersonal relationship improves performance in guided interactions at the expense of the free interactive ones. This was paralleled at the kinematic level by the absence of movement corrections and by low movement variability in these participants, indicating that partners cooperating within a negative interpersonal bond executed the cooperative task on their own, without reciprocally adapting to the partner''s motor behaviour. Crucially, participants'' performance in the free interaction improved in the manipulated group during the second experimental session while partners became interdependent as suggested by higher movement variability and by the appearance of interference between the self-executed actions and those observed in the partner. Our study expands current knowledge about on-line motor interactions by showing that visuo-motor interference effects, mutual motor adjustments and motor-learning mechanisms are influenced by social perception. 相似文献
997.
998.
999.
Simon J. Hogg Olga Motorna Leonie A. Cluse Timothy M. Johanson Hannah D. Coughlan Ramya Raviram Robert M. Myers Matteo Costacurta Izabela Todorovski Lizzy Pijpers Stefan Bjelosevic Tobias Williams Shannon N. Huskins Conor J. Kearney Jennifer R. Devlin Zheng Fan Jafar S. Jabbari Ben P. Martin Ricky W. Johnstone 《Molecular cell》2021,81(10):2183-2200.e13
1000.