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991.
Fataki Bombil Jean Pierre Kints Xavier Havaux Jean Marie Scheiff Hervé Bazin Dominique Latinne 《Cancer immunology, immunotherapy : CII》1995,40(6):383-389
The transfer of human peripheral blood mononuclear cells (hu-PBMC) from adult Epstein-Barr- virus(EBV)-seropositive donors
in SCID (severe combined immunodeficiency) mice frequently leads to the development of a human B lymphoproliferative syndrome
(hu-BLPS). Therefore, as 90% of adult potential donors are EBV-seropositive, efforts have to be made to avoid the occurrence
of this B lymphoproliferative disorder. McCune et al. [Science 241:1632 (1988)] used human fetal organs for a human SCID graft.
This system does not give rise to hu-BLPS but human fetal organs are much less available than peripheral blood leucocytes.
The experiments reported in this paper show how crucial is the presence of functional T lymphocytes for a graft to take and for development of hu-BLPS in hu-PBMC-reconstituted SCID mice, since inhibition of
T lymphocyte by a rat anti-(human CD2) monoclonal antibody (LO-CD2a) during the first 10 days of the graft prevents successful
engraftment of human normal lymphocytes as well as hu-BLPS in SCID mice. The transfer of B cells alone or B cells plus monocytes
in SCID mice does not permit either long-term engraftment or development of hu-BLPS. We also demonstrate that hu-PBMC treated
with L-leucine methyl ester are less susceptible to the development of hu-BLPS after engraftment in SCID mice than are untreated
hu-PBMC. The mechanism of action of L-leucine methyl ester on these cells is discussed.
Received: 12 December 1994 / Accepted: 20 March 1995 相似文献
992.
An ultrastructural study of the manchette was carried out on 21 species belonging to the culicid genera Aedes, Anopheles, Culex and Toxorhynchites . Each genus has a characteristic morphological type of manchette. Toxorhynchites seems to have the type found in many other Diptera, while the other genera have unusual types. 相似文献
993.
994.
Endurance training affects myosin heavy chain phenotype in regenerating fast-twitch muscle 总被引:2,自引:0,他引:2
Bigard Xavier A.; Janmot Chantal; Merino Daniele; Lienhard Francoise; Guezennec Yannick C.; D'Albis Anne 《Journal of applied physiology》1996,81(6):2658-2665
Bigard, Xavier A., Chantal Janmot, Danièle Merino,Françoise Lienhard, Yannick C. Guezennec, and Anne D'Albis.Endurance training affects myosin heavy chain phenotype inregenerating fast-twitch muscle. J. Appl.Physiol. 81(6): 2658-2665, 1996.The aim of thisstudy was to analyze the effects of treadmill training (2 h/day, 5 days/wk, 30 m/min, 7% grade for 5 wk) on the expression of myosinheavy chain (MHC) isoforms during and after regeneration of afast-twitch white muscle [extensor digitorum longus (EDL)]. Male Wistar rats were randomly assigned to a sedentary(n = 10) or an endurance-trained (ET;n = 10) group. EDL muscle degeneration and regeneration were induced by two subcutaneous injections of a snaketoxin. Five days after induction of muscle injury, animals were trainedover a 5-wk period. It was verified that ~40 days after venomtreatment, central nuclei were present in the treated EDL muscles fromsedentary and ET rats. The changes in the expression of MHCs in EDLmuscles were detected by using a combination of biochemical andimmunocytochemical approaches. Compared with contralateral nondegenerated muscles, relative concentrations of types I, IIa, andIIx MHC isoforms in ET rats were greater in regenerated EDL muscles(146%, P < 0.05; 76%,P < 0.01; 87%,P < 0.01, respectively). Their elevation corresponded to a decreasein the relative concentration of type IIb MHC (36%,P < 0.01). Although type I accountedfor only 3.2% of total myosin in regenerated muscles from the ETgroup, the cytochemical analysis showed that the proportion of positive staining with the slow MHC antibody was markedly greater in regenerated muscles than in contralateral ones. Collectively, these results demonstrate that the regenerated EDL muscle is sensitive to endurance training and suggest that the training-induced shift in MHC isoforms observed in these muscles resulted from an additive effect of regeneration and repeated exercise. 相似文献
995.
Implication of mitochondria in apoptosis 总被引:17,自引:0,他引:17
Patrice Xavier Petit Naoufal Zamzami Jean-Luc Vayssière Bernard Mignotte Guido Kroemer Maria Castedo 《Molecular and cellular biochemistry》1997,174(1-2):185-188
The induction phase of programmed cell death (PCD) or apoptosis is characterized by an extreme heterogeneity of potential PCD-triggering signal transduction pathways. During the subsequent effector phase, the numerous PCD-inducing stimuli converge into a few stereotypical pathways and cells pass a 'point of no return', thus becoming irreversibly committed to death. Evidence is accumulating that cytoplasmic structures, including mitochondria, participate in the critical effector stage and that alterations usually considered to define apoptosis, as nuclear chromatolysis and cytolysis, have to be ascribed to the late degradation phase. We and others have recently shown that nuclear features of apoptosis are preceded by alterations in mitochondrial function and structure. The importance of these alterations for the apoptotic process and also the possible link between, these observations, the permeability transition pore and the programmed cell death, are dicussed. (Mol Cell Biochem 174: 185–188, 1997) 相似文献
996.
A. M. A. Nascimento H. R. T. Souza M. S. Xavier J. E. Thiemann L. Vilela M. Mares-Guia 《Biotechnology Techniques》1996,10(10):737-742
Summary A proinsulin analog constructed by site-directed mutagenesis was expressed as a fusion protein that formed inclusion bodies inside the cells. It was purified from the isolated inclusion bodies and proinsulin was obtained by trifluoro-acetic acid, dimethyl sulfoxide and hydrochloric acid cleavage. The released proinsulin analog was confirmed by its molecular weight as determined by SDS-PAGE. 相似文献
997.
F. Javier L. Gordillo Carlos Jiménez Alfonso Corzo F. Xavier Niell 《Journal of applied phycology》1997,9(2):99-106
An in situ method for measuring nitrate reductase (NR) activity in Dunaliella viridis was optimized in terms of incubation
time, concentration of KNO3, permeabilisers (1-propanol and toluene), pH, salinity, and reducing power (glucose and NADH). NR activity was measured by
following nitrite production and was best assayed with 50 mM KNO3, 1.2 mM NADH, 5% 1-propanol (v/v), at pH 8.5. The estimated half-saturation constant (Ks) for KNO3 was 5 mM. Glucose had no effect as external reducing power source, and NADH concentrations >1.2 mM inhibited NR activity.
Nitrite production was linear up to 20 min; longer incubation did not lead to higher nitrate reduction. The use of the optimized
assay predicted the rate of NO
3
−
removal from the external medium by D. viridis with high degree of precision.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
998.
Joan Rieradevall Xavier Domènech Pere Fullana 《The International Journal of Life Cycle Assessment》1997,2(3):141-144
A case study of a life-cycle assessment (LCA) is performed concerning the treatment of household solid wastes in a landfill.
The stages considered in this LCA study are: goal and scope definition, inventory analysis and impact assessment. The data
of the inventory include the consumption of raw materials and energy through the transport of wastes and the management of
landfill, and the corresponding emissions to the environment. Abiotic resource depletion, global warming, acidification, eutrophication
and human toxicological impacts have been considered as impact categories for the impact assessment phase of the LCA. A comparison
of the environmental impact of the landfilling with and without energy recovery is carried out.
Members of the Spanish Association for LCA Development (APRODACV) 相似文献
999.
A proposed architecture for the central domain of the bacterial enhancer-binding proteins based on secondary structure prediction and fold recognition 下载免费PDF全文
Joel Osuna Xavier Soberon Enrique Morett 《Protein science : a publication of the Protein Society》1997,6(3):543-555
The expression of genes transcribed by the RNA polymerase with the alternative sigma factor <r54 (Ecr54) is absolutely dependent on activator proteins that bind to enhancer-like sites, located far upstream from the promoter. These unique prokaryotic proteins, known as enhancer-binding proteins (EBP), mediate open promoter complex formation in a reaction dependent on NTP hydrolysis. The best characterized proteins of this family of regulators are NtrC and Nif A, which activate genes required for ammonia assimilation and nitrogen fixation, respectively. In a recent IRBM course (“Frontiers of protein structure prediction,” IRBM, Pomezia, Italy, 1995; see web site http://www.mrc-cpe.cam.uk/ irbm-course95/), one of us (J.O.) participated in the elaboration of the proposal that the Central domain of the EBPs might adopt the classical mononucleotide-binding fold. This suggestion was based on the results of a new protein fold recognition algorithm (Map) and in the mapping of correlated mutations calculated for the sequence family on the same mononucleotide-binding fold topology. In this work, we present new data that support the previous conclusion. The results from a number of different secondary structure prediction programs suggest that the Central domain could adopt an alfi topology. The fold recognition programs ProFIT 0.9, 3D PROFILE combined with secondary structure prediction, and 123D suggest a mononucleotide-binding fold topology for the Central domain amino acid sequence. Finally, and most importantly, three of five reported residue alterations that impair the Central domain ATPase activity of the Eo-54 activators are mapped to polypeptide regions that might be playing equivalent roles as those involved in nucleotide-binding in the mononucleotide-binding proteins. Furthermore, the known residue substitutions that alter the function of the Ecr54 activators, leaving intact the Central domain ATPase activity, are mapped on a region proposed to play an equivalent role as the effector region of the GTPase superfamily. 相似文献
1000.