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941.
942.
N. V. Kozlova Olga K. Strunnikova Natalia M. Labutova George S. Muromtsev 《Mycorrhiza》2001,10(6):301-305
Rabbit polyclonal antibodies were produced against a soluble protein fraction from a vesicle and spore mixture of the arbuscular
mycorrhizal fungus (AMF) Glomus intraradices. The protocol for isolation of vesicles and spores from plant roots was optimized to minimize debris contamination. Protein
extract purification and preparation for immunization was adapted to increase protein content and immunogenicity. Active antisera
were produced starting from the second boost immunization. Antibodies obtained were specific for surface antigens of AMF and
revealed different patterns of soluble protein antigens in G. intraradices, G. constrictum and an unidentified Glomus species.
Accepted: 6 December 2000 相似文献
943.
This article describes a method to detect and analyze dynamic interactions between a protein of interest and other factors in vivo. Our method is based on the amber suppression technology that was originally developed by Peter Schultz and colleagues1. An amber mutation is first introduced at a specific codon of the gene encoding the protein of interest. The amber mutant is then expressed in E. coli together with genes encoding an amber suppressor tRNA and an amino acyl-tRNA synthetase derived from Methanococcus jannaschii. Using this system, the photo activatable amino acid analog p-benzoylphenylalanine (Bpa) is incorporated at the amber codon. Cells are then irradiated with ultraviolet light to covalently link the Bpa residue to proteins that are located within 3-8 Å. Photocrosslinking is performed in combination with pulse-chase labeling and immunoprecipitation of the protein of interest in order to monitor changes in protein-protein interactions that occur over a time scale of seconds to minutes. We optimized the procedure to study the assembly of a bacterial virulence factor that consists of two independent domains, a domain that is integrated into the outer membrane and a domain that is translocated into the extracellular space, but the method can be used to study many different assembly processes and biological pathways in both prokaryotic and eukaryotic cells. In principle interacting factors and even specific residues of interacting factors that bind to a protein of interest can be identified by mass spectrometry. 相似文献
944.
Edita Tylov�� Lenka Steinbachov�� Ale? Soukup V��t Gloser Olga Votrubov�� 《Hydrobiologia》2013,700(1):141-155
Phragmites australis and Glyceria maxima are fast-growing littoral grasses often competing for similar wetland habitats. Eutrophication affects their competitiveness, but the outcome is not generally predictable due to the complexity of interrelated factors. We hypotheses that pore water N:P and NH4 +:NO3 ? modify their growth and metabolic responses to the trophic status of the habitat. The hypothesis was tested under standardized conditions of long-term sand cultures. Application of N?+?P up to extreme levels in combination with N:P?<?10 and NH4 +:NO3 ??<?1 triggered positive growth response in both species. In contrast, similar N levels applied in N:P?>?90 and NH4 +:NO3 ??=?4 caused lower productivity, changes in resource allocation, morphology and metabolic relations (e.g. high shoot density, low shoot diameters and heights, reduced root and rhizome growth). Observed signs of stress resembled the factors associated with the reed retreat at the die-back sites. Unbalanced N levels obviously alter plant susceptibility to stresses (altering, e.g. ventilation efficiency, plant anchorage or below-ground storage capacity). The positive effect of sufficient P supply was pronounced in Glyceria. It might therefore favour Glyceria in competition with Phragmites at highly fertile habitats rich in P. 相似文献
945.
946.
947.
Torben Clausen Tove Lindahl Andersen Marianne Stürup-Johansen Olga Petkova 《生物化学与生物物理学报:生物膜》1981,646(2):261-267
(1) The effects of vanadate of hexose transport, 45Ca-exchange and (Na+, K+)-contents have been characterized in isolated adipose tissue and skeletal muscles of the rat. (2) In whole epididymal fat pads, vanadate (0.5–5.0 mM) markedly stimulated the uptake of 2-deoxyl[14C]glucose as well as the efflux of . (3) Within the same concentration range, vanadate induced an early increase in 45Ca-washout from preloaded fat pads. The maximum increases in the fractional losses of and 45Ca were significantly correlated (, ). (4) In extensor digitorum longus and soleus muscles, vanadate (0.5–5.0 mM) stimulated the efflux of and this effect was preceded by a rise in the washout of 45Ca. The maximum increases in the fractional losses of and 45Ca were significantly correlated (, ). (5) In extensor digitorum longus and soleus muscles, vanadate increased K+-contents and decreased Na+ contents. (6) The stimulation of 45Ca-washout presumably reflects an increase in the cytoplasmic Ca2+ level, brought about by an inhibitory effect of vanadate on the Ca2+-sensitive ATPase of the sarcoplasmic or the endoplasmic reticulum. As demonstrated for most other insulin-like agents (Sørensen, S.S., Christensen, F. and Clausen, T. (1980) Biochim. Biophys. Acta 602, 433–445), the stimulating effect of vanadate on glucose transport appears to be associated with or mediated by a rise in the cytoplasmic Ca2+ level. 相似文献
948.
949.
Background
The family of c-Jun NH2-terminal kinases (JNK) plays important roles in embryonic development and in cellular responses to stress. Toxic metals and their compounds are potent activators of JNK in mammalian cells. The mechanism of mammalian JNK activation by cadmium and sodium arsenite involves toxicant-induced oxidative stress. The study of mammalian signaling pathways to JNK is complicated by the significant degree of redundancy among upstream JNK regulators, especially at the level of JNK kinase kinases (JNKKK). 相似文献950.
Decorin is the archetypal small leucine rich repeat proteoglycan of the vertebrate extracellular matrix (ECM). With its glycosaminoglycuronan chain, it is responsible for stabilizing inter-fibrillar organization. Type I collagen is the predominant member of the fibrillar collagen family, fulfilling both organizational and structural roles in animal ECMs. In this study, interactions between decoron (the decorin core protein) and binding sites in the d and e1 bands of the type I collagen fibril were investigated through molecular modeling of their respective X-ray diffraction structures. Previously, it was proposed that a model-based, highly curved concave decoron interacts with a single collagen molecule, which would form extensive van der Waals contacts and give rise to strong non-specific binding. However, the large well-ordered aggregate that is the collagen fibril places significant restraints on modes of ligand binding and necessitates multi-collagen molecular contacts. We present here a relatively high-resolution model of the decoron-fibril collagen complex. We find that the respective crystal structures complement each other well, although it is the monomeric form of decoron that shows the most appropriate shape complementarity with the fibril surface and favorable calculated energies of interaction. One molecule of decoron interacts with four to six collagen molecules, and the binding specificity relies on a large number of hydrogen bonds and electrostatic interactions, primarily with the collagen motifs KXGDRGE and AKGDRGE (d and e1 bands). This work helps us to understand collagen-decorin interactions and the molecular architecture of the fibrillar ECM in health and disease. 相似文献