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61.
Labarrère P Chatenet D Leprince J Marionneau C Loirand G Tonon MC Dubessy C Scalbert E Pfeiffer B Renard P Calas B Pacaud P Vaudry H 《Journal of enzyme inhibition and medicinal chemistry》2003,18(2):77-88
The sequence of human urotensin II (UII) has been recently established as H-Glu-Thr-Pro-Asp-Cys-Phe-Trp-Lys-Tyr-Cys-Val-OH, and it has been reported that UII is the most potent mammalian vasoconstrictor peptide identified so far. A series of UII analogues was synthesized, and the contractile activity of each compound was studied in vitro using de-endothelialised rat aortic rings. Replacement of each amino acid by an L-alanine or by a D-isomer showed that the N- and C-terminal residues flanking the cyclic region of the amidated peptide were relatively tolerant to substitution. Conversely, replacement of any residue of the cyclic region significantly reduced the contractile activity of the molecule. The octapeptide UII(4-11) was 4 times more potent than UII, indicating that the C-terminal region of the molecule possesses full biological activity. Alanine or D-isomer substitutions in UII(4-11) or in UII(4-11)-NH2, respectively, showed a good correlation with the results obtained for UII-NH2. Disulfide bridge disruption or replacement of the cysteine residues by their D-enantiomers markedly reduced the vasoconstrictor effect of UII and its analogues. In contrast, acetylation of the N-terminal residue of UII and UII-NH2 enhanced the potency of the peptide. Finally, monoiodination of the Tyr6 residue in UII(4-11) increased by 5 fold the potency of the peptide in the aortic ring bioassay. This structure-activity relationship study should provide useful information for the rational design of selective and potent UII receptor agonists and antagonists. 相似文献
62.
In Vivo Evidence That the Stromelysin-3 Metalloproteinase Contributes in a Paracrine Manner to Epithelial Cell Malignancy 总被引:8,自引:0,他引:8
Rgis Masson Olivier Lefebvre Agns Noël Mostapha El Fahime Marie-Pierre Chenard Corinne Wendling Florence Kebers Marianne LeMeur Andre Dierich Jean-Michel Foidart Paul Basset Marie-Christine Rio 《The Journal of cell biology》1998,140(6):1535-1541
Stromelysin-3 (ST3; Basset, P., J.P. Bellocq, C. Wolf, I. Stoll, P. Hutin, J.M. Limacher, O.L. Podhajcer, M.P. Chenard, M.C. Rio, P. Chambon. 1990. Nature. 348:699–704) is a matrix metalloproteinase (MMP) expressed in mesenchymal cells located close to epithelial cells, during physiological and pathological tissue remodeling processes. In human carcinomas, high ST3 levels are associated with a poor clinical outcome, suggesting that ST3 plays a role during malignant processes. In this study we report the ST3 gene inactivation by homologous recombination. Although ST3 null mice (ST3−/−) were fertile and did not exhibit obvious alterations in appearance and behavior, the lack of ST3 altered malignant processes. Thus, the suppression of ST3 results in a decreased 7,12-dimethylbenzanthracene-induced tumorigenesis in ST3−/− mice. Moreover, ST3−/− fibroblasts have lost the capacity to promote implantation of MCF7 human malignant epithelial cells in nude mice (P < 0.008). Finally, we show that this ST3 paracrine function requires extracellular matrix (ECM)-associated growth factors. Altogether, these findings give evidence that ST3 promotes, in a paracrine manner, homing of malignant epithelial cells, a key process for both primary tumors and metastases. Therefore, ST3 represents an appropriate target for specific MMP inhibitor(s) in future therapeutical approaches directed against the stromal compartment of human carcinomas. 相似文献
63.
Raulin-Cerceau Florence Maurel Marie-Christine Schneider Jean 《Origins of life and evolution of the biosphere》1998,28(4-6):597-612
During the 19th and early 20th centuries, ideas related to the possible origin in space of bioorganic molecules, or seeds, or even germs and organisms (and how they reached the Earth) included the Panspermia theory. Based on the idea of the eternity of life proposed by eminent physicists – such as Arrhenius and Kelvin – Panspermia is mainly divided into two branches: lithopanspermia (transport of germs inside stones traveling in space) and radiopanspermia (transport of spores by radiative pressure of stellar light). We point out some arguments to help to understand whether Panspermia could exist nowadays as the same theory defined one century ago. And we wonder about the kind of evolution Panspermia could have undergone during only a few decades. This possible evolution of the Panspermia concept takes place in the framework of the emergence of a new field, Bioastronomy. We present how this discipline has emerged during a few decades and how it has evolved. We consider its relationship with the progression of other scientific fields, and finally we examine how it is now included in different projects of space agencies. Bioastronomy researches having become more and more robust during the last few years, we emphasize several questions about new ideas and their consequences for the current hypothesis of Panspermia and of universal life. 相似文献
64.
Thomas Landes Ingrid Leroy Ambre Bertholet Alan Diot Farnoosh Khosrobakhsh Marlène Daloyau Noélie Davezac Marie-Christine Miquel Delphine Courilleau Emmanuelle Guillou Aurélien Olichon Guy Lenaers Laetitia Arnauné-Pelloquin Laurent J. Emorine Pascale Belenguer 《Seminars in cell & developmental biology》2010,21(6):593-598
Mitochondrial morphology varies according to cell type and cellular context from an interconnected filamentous network to isolated dots. This morphological plasticity depends on mitochondrial dynamics, a balance between antagonistic forces of fission and fusion. DRP1 and FIS1 control mitochondrial outer membrane fission and Mitofusins its fusion. This review focuses on OPA1, one of the few known actors of inner membrane dynamics, whose mutations provoke an optic neuropathy. Since its first identification in 2000 the characterization of the functions of OPA1 has made rapid progress thus providing numerous clues to unravel the pathogenetic mechanisms of ADOA-1. 相似文献
65.
Julio Aires Patricia Anglade Fabienne Baraige Monique Zagorec Marie-Christine Champomier-Vergès Marie-José Butel 《BMC microbiology》2010,10(1):29
Background
Bifidobacteria are natural inhabitants of the human gastrointestinal tract. In full-term newborns, these bacteria are acquired from the mother during delivery and rapidly become the predominant organisms in the intestinal microbiota. Bifidobacteria contribute to the establishment of healthy intestinal ecology and can confer health benefits to their host. Consequently, there is growing interest in bifidobacteria, and various strains are currently used as probiotic components in functional food products. However, the probiotic effects have been reported to be strain-specific. There is thus a need to better understand the determinants of the observed benefits provided by these probiotics. Our objective was to compare three human B. longum isolates with the sequenced model strain B. longum NCC2705 at the chromosome and proteome levels. 相似文献66.
Delphine Benaitreau Esther Dos Santos Marie-Christine Leneveu Philippe De Mazancourt René Pecquery Marie-Noëlle Dieudonné 《Reproductive biology and endocrinology : RB&E》2010,8(1):128
Background
In human pregnancy, a correct placentation depends on trophoblast proliferation, differentiation, migration and invasion. These processes are highly regulated by placental hormones, growth factors and cytokines. Recently, we have shown that adiponectin, an adipokine, has anti-proliferative effects on trophoblastic cells. Here, we complete this study by demonstrating that adiponectin modulates BeWo and human villous cytotrophoblast cell differentiation. 相似文献67.
Damien Sanlaville Capucine Delnatte Jean-Franois Mougenot Joris-Robert Vermeesch Claude Houdayer Marie-Christine de
Blois David Genevieve Olivier Goulet Jean-Pierre Fryns Francis Jaubert Michel Vekemans Stanislas Lyonnet Serge Romana Charis Eng Dominique Stoppa-Lyonnet 《American journal of human genetics》2006,79(3):596-597
68.
Saint-Jore-Dupas C Claude SJ Gilbert MA Marie-Agnès G Ramis C Catalina R Paris N Nadine P Kiefer-Meyer MC Marie-Christine KM Neuhaus JM Jean-Marc N Faye L Loïc F Gomord V Véronique G 《Plant & cell physiology》2005,46(10):1603-1612
Concanavalin A (ConA) is a well characterized and extensively used lectin accumulated in the protein bodies of jack bean cotyledons. ConA is synthesized as an inactive precursor proConA. The maturation of inactive proConA into biologically active ConA is a complex process including the removal of an internal glycopeptide and a C-terminal propeptide (CTPP), followed by a head-to-tail ligation of the two largest polypeptides. The cDNA encoding proConA was cloned and expressed in tobacco BY-2 cells. ProConA was slowly transported to the vacuole where its maturation into ConA was similar to that in jack bean cotyledons, apart from an incomplete final ligation. To investigate the role of the nine amino acid CTPP, a truncated form lacking the propeptide (proConADelta9) was expressed in BY-2 cells. In contrast to proConA, proConADelta9 was rapidly chased out of the endoplasmic reticulum (ER) and secreted into the culture medium. The CTPP was then fused to the C-terminal end of a secreted form of green fluorescent protein (secGFP). When expressed in tobacco BY-2 cells and leaf protoplasts, the chimaeric protein was located in the vacuole whereas secGFP was located in the culture medium and in the vacuole. Altogether, our results show we have isolated a new C-terminal vacuolar sorting determinant. 相似文献
69.
Reports provide conflicting data about the effects of alcohol consumption on the hormonal system. Any study of these effects must control for a number of variables, including sex, alcohol status (alcoholic addiction vs. non-addiction), medical status (malnutrition, liver disease), and conditions of alcohol exposure, including an acute or continuous pattern of intake. The latter appears to be an especially critical factor in interpreting these effects. The authors therefore conducted a trial with a circadian design in which alcohol was administered repeatedly and regularly over a 26 h period for a total dose of 256 g. Because this protocol involves continuous alcohol administration, it is similar to administration among alcoholics and thus sheds new light on alcohol's effect on hormone secretion. Using healthy volunteers rather than alcoholics, however, prevents any confounding due to liver disorders and nutritional deficiencies, and thus makes it possible to focus on the direct role of alcohol in hormonal modifications. In these conditions, the continuous administration of alcohol did not affect cortisol secretion, but serum testosterone levels were significantly higher at all time points during the alcohol session than at the corresponding time points during the control session. These data are not consistent with previously reported findings for the relation between alcohol and both cortisol and testosterone, because in the current experiment the action of ethanol on steroid secretion should involve the circadian clock more than the hormonal system itself. 相似文献
70.
Sánchez B Champomier-Vergès MC Stuer-Lauridsen B Ruas-Madiedo P Anglade P Baraige F de los Reyes-Gavilán CG Johansen E Zagorec M Margolles A 《Applied and environmental microbiology》2007,73(21):6757-6767
Bile salts are natural detergents that facilitate the digestion and absorption of the hydrophobic components of the diet. However, their amphiphilic nature makes them very inhibitory for bacteria and strongly influences bacterial survival in the gastrointestinal tract. Adaptation to and tolerance of bile stress is therefore crucial for the persistence of bacteria in the human colonic niche. Bifidobacterium animalis subsp. lactis, a probiotic bacterium with documented health benefits, is applied largely in fermented dairy products. In this study, the effect of bile salts on proteomes of B. animalis subsp. lactis IPLA 4549 and its bile-resistant derivative B. animalis subsp. lactis 4549dOx was analyzed, leading to the identification of proteins which may represent the targets of bile salt response and adaptation in B. animalis subsp. lactis. The comparison of the wild-type and the bile-resistant strain responses allowed us to hypothesize about the resistance mechanisms acquired by the derivative resistant strain and about the bile salt response in B. animalis subsp. lactis. In addition, significant differences in the levels of metabolic end products of the bifid shunt and in the redox status of the cells were also detected, which correlate with some differences observed between the proteomes. These results indicate that adaptation and response to bile in B. animalis subsp. lactis involve several physiological mechanisms that are jointly dedicated to reduce the deleterious impact of bile on the cell's physiology. 相似文献