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991.
Ga?l Latour Laura Kowalczuk Michèle Savoldelli Jean-Louis Bourges Karsten Plamann Francine Behar-Cohen Marie-Claire Schanne-Klein 《PloS one》2012,7(11)
Background
Second Harmonic Generation (SHG) microscopy recently appeared as an efficient optical imaging technique to probe unstained collagen-rich tissues like cornea. Moreover, corneal remodeling occurs in many diseases and precise characterization requires overcoming the limitations of conventional techniques. In this work, we focus on diabetes, which affects hundreds of million people worldwide and most often leads to diabetic retinopathy, with no early diagnostic tool. This study then aims to establish the potential of SHG microscopy for in situ detection and characterization of hyperglycemia-induced abnormalities in the Descemet’s membrane, in the posterior cornea.Methodology/Principal Findings
We studied corneas from age-matched control and Goto-Kakizaki rats, a spontaneous model of type 2 diabetes, and corneas from human donors with type 2 diabetes and without any diabetes. SHG imaging was compared to confocal microscopy, to histology characterization using conventional staining and transmitted light microscopy and to transmission electron microscopy. SHG imaging revealed collagen deposits in the Descemet’s membrane of unstained corneas in a unique way compared to these gold standard techniques in ophthalmology. It provided background-free images of the three-dimensional interwoven distribution of the collagen deposits, with improved contrast compared to confocal microscopy. It also provided structural capability in intact corneas because of its high specificity to fibrillar collagen, with substantially larger field of view than transmission electron microscopy. Moreover, in vivo SHG imaging was demonstrated in Goto-Kakizaki rats.Conclusions/Significance
Our study shows unambiguously the high potential of SHG microscopy for three-dimensional characterization of structural abnormalities in unstained corneas. Furthermore, our demonstration of in vivo SHG imaging opens the way to long-term dynamical studies. This method should be easily generalized to other structural remodeling of the cornea and SHG microscopy should prove to be invaluable for in vivo corneal pathological studies. 相似文献992.
Natalie Fournier Nesrine AttiaDelphine Rousseau-Ralliard Benoît VedieFrédéric Destaillats Alain Grynberg Jean-Louis Paul 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2012,1821(2):303-312
Consumption of trans fatty acids (TFA) increase cardiovascular risk more than do saturated FA, but the mechanisms explaining their atherogenicity are still unclear. We investigated the impact of membrane incorporation of TFA on cholesterol efflux by exposing J774 mouse macrophages or human monocyte-derived macrophages (HMDM) to media enriched or not (standard medium) with industrially produced elaidic (trans-9 18:1) acid, naturally produced vaccenic (trans-11 18:1) acid (34 h, 70 μM) or palmitic acid. In J774 macrophages, elaidic and palmitic acid, but not vaccenic acid, reduced ABCA1-mediated efflux by ~ 23% without affecting aqueous diffusion, SR-BI or ABCG1-mediated pathways, and this effect was maintained in cholesterol-loaded cells. The impact of elaidic acid on the ABCA1 pathway was weaker in cholesterol-normal HMDM, but elaidic acid induced a strong reduction of ABCA1-mediated efflux in cholesterol-loaded cells (− 36%). In J774 cells, the FA supplies had no impact on cellular free cholesterol or cholesteryl ester masses, the abundance of ABCA1 mRNA or the total and plasma membrane ABCA1 protein content. Conversely, TFA or palmitic acid incorporation induced strong modifications of the membrane FA composition with a decrease in the ratio of (cis-monounsaturated FA + polyunsaturated FA):(saturated FA + TFA), with elaidic and vaccenic acids representing each 20% and 13% of the total FA composition, respectively. Moreover, we demonstrated that cellular ATP was required for the effect of elaidic acid, suggesting that it contributes to atherogenesis by impairing ABCA1-mediated cholesterol efflux in macrophages, likely by decreasing the membrane fluidity, which could thereby reduce ATPase activity and the function of the transporter. 相似文献
993.
A short historical survey recalls the main techniques of medical imaging, based on modern physico-chemistry and computer science. Imagery has provided novel visions of the inside of the body, which are not self-obvious but require a training of the gaze. Yet, these new images have permeated the contemporary mind and inspired esthetic ventures. The popularity of these images may be related to their ambiguous status, between real and virtual. The images, reminiscent of Vesalius' De humani corporis fabrica, crosslink art, science and society in a specific way: which role will they play in the "empowerment" of the tomorrow patient? 相似文献
994.
Michèle Kervella Jean-Louis Fauchère Didier Fourel Jean-Mari Pagès 《FEMS microbiology letters》1992,99(2-3):281-286
Immunocrossreactivity between the major outer membrane protein (MOMP) of Campylobacter jejuni 85H and the OmpC porin of Escherichia coli K-12 was observed. These results indicate that a common antigenic domain is conserved in both MOMP and OmpC. This antigenic region is detected only after a 96 degrees C treatment suggesting that it is buried in the native conformation of the respective porins. In addition, differences were observed between the major outer membrane proteins from various C. jejuni strains. About 60% of the C. jejuni pathogenic strains tested contained a protein exhibiting a similar electrophoretic profile to the 85H porin. 相似文献
995.
996.
Jean-Louis Franc Simone Bouchilloux 《Biochimica et Biophysica Acta (BBA)/General Subjects》1984,800(2):166-170
The ability of dolichyl-P-P-oligosaccharide:peptide oligosaccharyltransferase to use exogenous substrates (a previously labeled oligosaccharide lipid and an Asn-X-Thr containing heptapeptide) is shown to require phospholipid. The enzyme was extracted from porcine thyroid rough microsomes using NaCl-Nonidet P-40. When measured at low concentration, in a neutral detergent-containing medium, it undergoes a rapid loss of activity, which renders impossible quantitative estimates in the range of 0–50 μg microsomal protein /50 μl assay. We observed that inactivation could be prevented by supplementing the assay with a prevoously heat-treated suspension of microsomes in neutral detergent, or with the corresponding extract. Further investigation revealed that phospholipids are responsible for this enzyme stabilization, since phospholipase A2 and phospholipase C treatments were both able to abolish this effect. When individual phospholipids were compared for their protective efficiency, egg yolk phosphatidylcholine was found to be by far the most efficient. Phosphatidylglycerol, phosphatidylinositol and phosphatidylserine were only slightly effective, while phosphatidylethanolamine and lysophosphatidylcholine had no effect at all. Of those tested, partly unsaturated phosphatidylcholines with 16–18 carbon atom acyl chains were the most active, at an optimal concentration of 1–2 mM. Under these conditions a Km of 15 μM was measured for the acceptor, a synthetic ribonuclease heptapeptide, and Km of 0.55 μM for the donor, dolichyl-P-P-GlcNAc2-Man9-Glc2?3. These findings were confirmed by subjecting a sodium deoxycholate extract to depletion of endogenous lipids by gel filtration. Enzyme activity was totally abolished and then restored (up to now only partially) by addition of phosphatidylcholine. 相似文献
997.
Joséphine Beck Laetitia Maton Jean-Louis Habib Jiwan Jacqueline Marchand-Brynaert 《Amino acids》2011,40(2):679-687
The complexation of calcium and zinc cations by pyrroglutamate analogs has been studied in the gas phase by means of electrospray
ionization mass spectrometry (ESI–MS). Complexes were obtained from the solutions of calcium perchlorate and zinc perchlorate
in acetonitrile. The complexes with calcium are singly and doubly charged with various stoichiometries while zinc complexes
are singly charged except for one ligand. Solvation with acetonitrile and presence of perchlorate counter-ions are observed
when the complexes are in the gas phase. The complexes formed with both metals are mainly L2M and LM species. All tested compounds are better complexing agents for calcium than for zinc. 相似文献
998.
EcoRI restriction-site polymorphism of the albumin gene in different inbred strains of rat 总被引:5,自引:0,他引:5
Gérard Lucotte Andras Gal Jean-Louis Nahon José M. Sala-Trepat 《Biochemical genetics》1982,20(11-12):1105-1115
Two types of variant EcoRI restriction enzyme patterns of albumin-gene DNA fragments have been detected in different rat strains by agarose gel electrophoresis and Southern blot hybridization using 32P-labeled cloned rat albumin cDNA probes. The type I albumin gene variant is characteristic of the Sprague-Dawley strain, and type II is found in Buffalo rats. The occurrence of these variants is interpreted as the result of simple allelic polymorphism because they are inherited in a normal Mendelian fashion when crossing Sprague-Dawley and Buffalo rats. The distribution of the two genetic variants in various inbred strains of rat suggests that type I represents the original or ancestral form of the albumin gene and that type II appeared spontaneously during laboratory breeding. 相似文献
999.
Odile Miret-Duvaux Florence Frederic Dominique Simon Jean-Louis Guenet ré Hanauer† Nicole Delhaye-Bouchaud Jean Mariani 《Journal of neurochemistry》1990,54(1):23-29
Many similarities of both the inheritance pattern and the neuropathology can be observed between olivopontocerebellar atrophies, or so-called multiple system atrophies (MSAs), and murine cerebellar mutations like Purkinje cell degeneration, nervous, staggerer, weaver, and reeler. Our study aimed to test whether the glutamate dehydrogenase (GDH) deficiency observed in some MSA patients could be found also in any of the murine mutants. GDH activity was assayed in several organs of these mutants, and no general deficiency was detected. By contrast, the level was found to be elevated in the cerebellum. The GDH gene was localized on mouse chromosome 14 and does not map close to any known neurological mutation in the mouse. We conclude, for the moment, that none of these cerebellar mutant mice can be considered as an animal model for GDH-deficient MSA. 相似文献
1000.