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1.
Clémence L. Gamblin émilie J.-L. Hardy Fran?ois J.-M. Chartier Nicolas Bisson Patrick Laprise 《The Journal of cell biology》2014,204(4):487-495
During epithelial cell polarization, Yurt (Yrt) is initially confined to the lateral membrane and supports the stability of this membrane domain by repressing the Crumbs-containing apical machinery. At late stages of embryogenesis, the apical recruitment of Yrt restricts the size of the apical membrane. However, the molecular basis sustaining the spatiotemporal dynamics of Yrt remains undefined. In this paper, we report that atypical protein kinase C (aPKC) phosphorylates Yrt to prevent its premature apical localization. A nonphosphorylatable version of Yrt dominantly dismantles the apical domain, showing that its aPKC-mediated exclusion is crucial for epithelial cell polarity. In return, Yrt counteracts aPKC functions to prevent apicalization of the plasma membrane. The ability of Yrt to bind and restrain aPKC signaling is central for its role in polarity, as removal of the aPKC binding site neutralizes Yrt activity. Thus, Yrt and aPKC are involved in a reciprocal antagonistic regulatory loop that contributes to segregation of distinct and mutually exclusive membrane domains in epithelial cells. 相似文献
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Athanassios Alevizopoulos Nicolas Mermod 《BioEssays : news and reviews in molecular, cellular and developmental biology》1997,19(7):581-591
Transforming growth factor-β (TGF-β) and its related proteins regulate broad aspects of body development, including cell proliferation, differentiation, apoptosis and gene expression, in various organisms. Deregulated TGF-β function has been causally implicated in the generation of human fibrotic disorders and in tumor progression. Nevertheless, the molecular mechanisms of TGF-β action remained essentially unknown until recently. Here, we discuss recent progress in our understanding of the mechanism of TGF-β signal transduction with respect to the regulation of gene expression, the control of cell phenotype and the potential usage TGF-β for the treatment of human diseases. 相似文献
4.
Jose Luis Lopez Guerra Nicolas Isa Michelle M. Kim Celine Bourgier Hugo Marsiglia 《Reports of Practical Oncology and Radiotherapy》2012,17(5):251-254
AimTo assess the role of the young radiation oncologist in the context of important recent advancements in the field of radiation oncology, and to explore new perspectives and competencies of the young radiation oncologist.BackgroundRadiation oncology is a field that has rapidly advanced over the last century. It holds a rich tradition of clinical care and evidence-based practice, and more recently has advanced with revolutionary innovations in technology and computer science, as well as pharmacology and molecular biology.Materials and methodsSeveral young radiation oncologists from different countries evaluated the current status and future directions of radiation oncology.ResultsFor young radiation oncologists, it is important to reflect on the current practice and future directions of the specialty as it relates to the role of the radiation oncologist in the comprehensive management of cancer patients. Radiation oncologists are responsible for the radiation treatment provided to patients and its subsequent impact on patients’ quality of life. Young radiation oncologists must proactively master new clinical, biological and technical information, as well as lead radiation oncology teams consisting of physicists, dosimetrists, nurses and technicians.ConclusionsThe role of the young radiation oncologist in the field of oncology should be proactive in developing new competencies. Above all, it is important to remember that we are dealing with the family members and loved ones of many individuals during the most difficult part of their lives. 相似文献
5.
Nicolas Tavaglione Angela K. Martin Nathalie Mezger Sophie Durieux‐Paillard Anne François Yves Jackson Samia A. Hurst 《Bioethics》2015,29(2):98-107
In the literature on medical ethics, it is generally admitted that vulnerable persons or groups deserve special attention, care or protection. One can define vulnerable persons as those having a greater likelihood of being wronged – that is, of being denied adequate satisfaction of certain legitimate claims. The conjunction of these two points entails what we call the Special Protection Thesis. It asserts that persons with a greater likelihood of being denied adequate satisfaction of their legitimate claims deserve special attention, care or protection. Such a thesis remains vague, however, as long as we do not know what legitimate claims are. This article aims at dispelling this vagueness by exploring what claims we have in relation to health care – thus fleshing out a claim‐based conception of vulnerability. We argue that the Special Protection Thesis must be enriched as follows: If individual or group X has a greater likelihood of being denied adequate satisfaction of some of their legitimate claims to (i) physical integrity, (ii) autonomy, (iii) freedom, (iv) social provision, (v) impartial quality of government, (vi) social bases of self‐respect or (vii) communal belonging, then X deserves special attention, care or protection. With this improved understanding of vulnerability, vulnerability talk in healthcare ethics can escape vagueness and serve as an adequate basis for practice. 相似文献
6.
Dominique Grizeau Lan Anh Bui Catherine Dupré Jack Legrand 《Critical reviews in biotechnology》2016,36(4):607-618
Over the last decades, production of microalgae and cyanobacteria has been developed for several applications, including novel foods, cosmetic ingredients and more recently biofuel. The sustainability of these promising developments can be hindered by some constraints, such as water and nutrient footprints. This review surveys data on N2-fixing cyanobacteria for biomass production and ways to induce and improve the excretion of ammonium within cultures under aerobic conditions. The nitrogenase complex is oxygen sensitive. Nevertheless, nitrogen fixation occurs under oxic conditions due to cyanobacteria-specific characteristics. For instance, in some cyanobacteria, the vegetative cell differentiation in heterocyts provides a well-adapted anaerobic microenvironment for nitrogenase protection. Therefore, cell cultures of oxygenic cyanobacteria have been grown in laboratory and pilot photobioreactors (Dasgupta et al., 2010; Fontes et al., 1987; Moreno et al., 2003; Nayak & Das, 2013). Biomass production under diazotrophic conditions has been shown to be controlled by environmental factors such as light intensity, temperature, aeration rate, and inorganic carbon concentration, also, more specifically, by the concentration of dissolved oxygen in the culture medium. Currently, there is little information regarding the production of extracellular ammonium by heterocytous cyanobacteria. This review compares the available data on maximum ammonium concentrations and analyses the specific rate production in cultures grown as free or immobilized filamentous cyanobacteria. Extracellular production of ammonium could be coupled, as suggested by recent research on non-diazotrophic cyanobacteria, to that of other high value metabolites. There is little information available regarding the possibility for using diazotrophic cyanobacteria as cellular factories may be in regard of the constraints due to nitrogen fixation. 相似文献
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Clément Lagrue Nicolas Kaldonski Sébastien Motreuil Thierry Lefèvre Olivier Blatter Philippe Giraud Loïc Bollache 《Biological invasions》2011,13(6):1409-1421
“Drifting” is known to subject aquatic invertebrates to intense predation by drift feeding fish. Consequently, interspecific
variations in drifting behaviour could lead to differences in predation pressure between coexisting prey species. Predation
being an important factor determining the success of invaders, differences in drift patterns could advantage either native
or exotic invertebrates through differential predation by native fish predators. The exotic freshwater amphipod (Gammarus roeseli) has now largely colonized Western Europe where it is often found in sympatry with a native species (Gammarus pulex). Here we documented interspecific differences in drifting behaviour that might have favored the invader’s success through
differential predation. Benthic and drifting amphipods were sampled three times at the same site to compare the proportion
of each species within and between sample types (benthos or drift) across time. Compared with the benthos, where the invader
(G. roeseli) was significantly less abundant than the native (G. pulex), G. roeseli was proportionally overrepresented in the drift but displayed a very different drifting pattern. While G. pulex drift rates remained roughly constant over a 24 h period, G. roeseli showed a marked diel periodicity with low diurnal and high nocturnal drift rates. Such drifting behaviour could procure this
species with a competitive advantage regarding predation as most drift feeding fish are diurnal. As a result, the native appears
more disadvantaged with respect to drift. This may partly explain the ability of G. roeseli to coexist with G. pulex in a habitat more suitable to the native. 相似文献
9.
Brand Eva Junne Stefan Anane Emmanuel Cruz-Bournazou Mariano Nicolas Neubauer Peter 《Bioprocess and biosystems engineering》2018,41(9):1305-1313
Bioprocess and Biosystems Engineering - Large-scale bioreactors are inhomogeneous systems, in which the fluid phase expresses concentration gradients. They depend on the mass transfer and fluid... 相似文献
10.
We describe a bioluminescent immunoassay procedure which does not require a separation step to remove excess free label. A luminescent immunosorbent constituted of bacterial luciferase, FMN oxidoreductase, and an antibody coimmobilized on Sepharose is used to determine specifically the label enzyme (glucose-6-phosphate dehydrogenase, coupled to an antigen) bound by a specific antibody. The immunosorbent confines the bioluminescent reaction in a small volume, and the bound label produces NADH, which is directly used by the nearby luciferase FMN oxidoreductase enzyme system. On the contrary NADH produced by dehydrogenases in solution is directly oxidized without emitting light. Dehydrogenases contained in the biological sample do not interfere with the assay, which can be performed directly on 25 microliter of serum. In this paper we describe the general procedure and we analyze the different parameters that must be optimized. 相似文献