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11.
Marc M. Nowaczyk Katharina Krause Maren Mieseler Anika Sczibilanski Masahiko Ikeuchi Matthias Rögner 《BBA》2012,1817(8):1339-1345
The life cycle of Photosystem II (PSII) is embedded in a network of proteins that guides the complex through biogenesis, damage and repair. Some of these proteins, such as Psb27 and Psb28, are involved in cofactor assembly for which they are only transiently bound to the preassembled complex. In this work we isolated and analyzed PSII from a ΔpsbJ mutant of the thermophilic cyanobacterium Thermosynechococcus elongatus. From the four different PSII complexes that could be separated the most prominent one revealed a monomeric Psb27–Psb28 PSII complex with greatly diminished oxygen-evolving activity. The MALDI-ToF mass spectrometry analysis of intact low molecular weight subunits (< 10 kDa) depicted wild type PSII with the absence of PsbJ. Relative quantification of the PsbA1/PsbA3 ratio by LC-ESI mass spectrometry using 15N labeled PsbA3-specific peptides indicated the complete replacement of PsbA1 by the stress copy PsbA3 in the mutant, even under standard growth conditions (50 μmol photons m? 2 s? 1). This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial. 相似文献
12.
Belle MD Pattison EF Cheunsuang O Stewart A Kramer I Sigrist M Arber S Morris R 《Genesis (New York, N.Y. : 2000)》2007,45(11):679-688
In this study, transgenic mice in which membrane-linked enhanced green fluorescent protein (mGFP) is expressed from the Thy1.2 promoter were used. In these mice, a subpopulation of small to medium sized DRG neurons double stained for IB4 but not for CGRP. Most of the peripheral terminals traversed the dermis and ramify within the epidermis and form superficial terminals. Within the spinal cord, these afferents terminated exclusively within the substantia gelatinosa (SG). A second fibre type in the skin also expressed mGFP, and formed club-shaped endings towards the bases of hairs. Injury to the sciatic nerve resulted in mGFP loss from the SG ipsilateral to the nerve injury, but also in the corresponding region contralaterally. Together, these findings reveal the specificity of connectivity of a defined subpopulation of DRG sensory neurons innervating the epidermis and this will facilitate analysis of their physiological functions. 相似文献
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14.
J Koenraad van de Wetering Lambert M G van Golde Joseph J Batenburg 《European journal of biochemistry》2004,271(7):1229-1249
Collectins are a family of collagenous calcium-dependent defense lectins in animals. Their polypeptide chains consist of four regions: a cysteine-rich N-terminal domain, a collagen-like region, an alpha-helical coiled-coil neck domain and a C-terminal lectin or carbohydrate-recognition domain. These polypeptide chains form trimers that may assemble into larger oligomers. The best studied family members are the mannan-binding lectin, which is secreted into the blood by the liver, and the surfactant proteins A and D, which are secreted into the pulmonary alveolar and airway lining fluid. The collectins represent an important group of pattern recognition molecules, which bind to oligosaccharide structures and/or lipid moities on the surface of microorganisms. They bind preferentially to monosaccharide units of the mannose type, which present two vicinal hydroxyl groups in an equatorial position. High-affinity interactions between collectins and microorganisms depend, on the one hand, on the high density of the carbohydrate ligands on the microbial surface, and on the other, on the degree of oligomerization of the collectin. Apart from binding to microorganisms, the collectins can interact with receptors on host cells. Binding of collectins to microorganisms may facilitate microbial clearance through aggregation, complement activation, opsonization and activation of phagocytosis, and inhibition of microbial growth. In addition, the collectins can modulate inflammatory and allergic responses, affect apoptotic cell clearance and modulate the adaptive immune system. 相似文献
15.
Nogai H Rosowski M Grün J Rietz A Debus N Schmidt G Lauster C Janitz M Vortkamp A Lauster R 《Differentiation; research in biological diversity》2008,76(4):404-416
Abstract Epithelial–mesenchymal transition (EMT) is involved in normal embryonic development as well as in tumor progression and invasiveness. This process is also known to be a crucial step in palatogenesis during fusion of the bi-lateral palatal processes. Disruption of this step results in a cleft palate, which is among the most frequent birth defects in humans. A number of genes and encoded proteins have been shown to play a role in this developmental stage. The central role is attributed to the cytokine transforming growth factor-β3 (TGF-β3), which is expressed in the medial edge epithelium (MEE) already before the fusion process. The MEE covers the tips of the growing palatal shelves and eventually undergoes EMT or programmed cell death (apoptosis). TGF-β3 is described to induce EMT in embryonic palates. With regard to the early expression of this molecule before the fusion process, it is not well understood which mechanisms prevent the TGF-β3 producing epithelial cells from undergoing differentiation precociously. We used the murine palatal fusion to study the regulation of EMT. Specifically, we analyzed the MEE for the expression of known antagonists of TGF-β molecules using in situ hybridization and detected the gene coding for Follistatin to be co-expressed with TGF-β3. Further, we could show that Follistatin directly binds to TGF-β3 and that it completely blocks TGF-β3-induced EMT of the normal murine mammary gland (NMuMG) epithelial cell line in vitro . In addition, we analyzed the gene expression profile of NMuMG cells during TGF-β3-induced EMT by microarray hybridization, detecting strong changes in the expression of apoptosis-regulating genes. 相似文献
16.
Homozygous mutation in SPATA16 is associated with male infertility in human globozoospermia 总被引:1,自引:0,他引:1 下载免费PDF全文
Dam AH Koscinski I Kremer JA Moutou C Jaeger AS Oudakker AR Tournaye H Charlet N Lagier-Tourenne C van Bokhoven H Viville S 《American journal of human genetics》2007,81(4):813-820
Globozoospermia is a rare (incidence <0.1% in male infertile patients) form of teratozoospermia, mainly characterized by round-headed spermatozoa that lack an acrosome. It originates from a disturbed spermiogenesis, which is expected to be induced by a genetic factor. Several family cases and recessive mouse models with the same phenotype support this expectation. In this study, we present a consanguineous family with three affected brothers, in whom we have identified a homozygous mutation in the spermatogenesis-specific gene SPATA16. This is the first example of a nonsyndromic male infertility condition in humans caused by an autosomal gene defect, and it could also mean that the identification of other partners like SPATA16 could elucidate acrosome formation. 相似文献
17.
Alexander P. Gultyaev F.H.D. van Batenburg Cornelis W.A. Pleij 《Journal of molecular evolution》2002,54(1):1-8
Comparison of the most stable potential hairpins in the sequences of natural ribozymes with those in the randomized sequences
has revealed that the hairpin loop energies are lower than expected by chance. Although these hairpins are not necessarily
parts of functional structures, there is a selective pressure to diminish the destabilizing free energies of the hairpin loops.
In contrast, no significant bias is observed in the stacking values of the most stable stems. In the ribozymes isolated in
vitro the loops of potential hairpins are closer to random values, which can result in less efficient folding rates. Furthermore,
the effects of kinetic traps seem to be more significant in the folding pathways of the in vitro isolates due to a potential
to form stable stacks incompatible with the functional folds. Similarly to natural ribozyme sequences, the untranslated regions
of viral RNAs also form hairpins with relatively low loop free energies. These evolutionary trends suggest ways for efficient
engineering of improved RNA constructs on the basis of analysis of in vitro isolates and approaches for the search of regions
coding for functional RNA structures in large genome sequences.
Received: 12 January 2001 / Accepted: 21 May 2001 相似文献
18.
Wickström SA Lange A Hess MW Polleux J Spatz JP Krüger M Pfaller K Lambacher A Bloch W Mann M Huber LA Fässler R 《Developmental cell》2010,19(4):574-588
Caveolae are specialized compartments of the plasma membrane that are involved in signaling, endocytosis, and cholesterol transport. Their formation requires the transport of caveolin-1 to the plasma membrane, but the molecular mechanisms regulating the transport are largely unknown. Here, we?identify a critical role for adhesion-mediated signaling through β1 integrins and integrin-linked kinase (ILK) in caveolae formation. Mice lacking β1 integrins or ILK in keratinocytes have dramatically reduced numbers of plasma membrane caveolae in?vivo, which is due to impaired transport of caveolin-1-containing vesicles along microtubules (MT) to the plasma membrane. Mechanistically, ILK promotes the recruitment of the F-actin binding protein IQGAP1 to the cell cortex, which, in turn, cooperates with its?effector mDia1 to locally stabilize MTs and to allow?stable insertion of caveolae into the plasma membrane. Our results assign an important role to the integrin/ILK complex for caveolar trafficking to the cell surface. 相似文献
19.