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41.
Alain de Chambrier 《Systematic parasitology》1990,16(2):85-97
Redescripción de Proteocephalus paraguayensis (Rudin, 1917) (Cestoda: Proteocephalidae), parásito de Hydrodynastes gigas (Dum., Bibr. & Dum., 1854) de Paraguay. Se describe esta especie notable, considerada por Freze (1965) como species inquirenda. Si comparamos esta especie con otras especies de Proteocephalidea, veremos que ella presenta caracteres anatomo-morfológicos propios. Esta especie se caracteriza por: vitelógenos de posición dorsal, adosados a la musculatura interna longitudinal, desbordando en parte sobre el córtex y la médula; formación particular del útero; posición cortical del tronco uterino y medular de los divertículos uterinos; esfínter vaginal proximal; cirro muy alargado; glándula de Mehlis muy desarrollada. Consideramos P. paraguayensis como una especie válida y presumimos que el huesped-tipo es Hydrodynastes gigas (Dum., Bibr. & Dum., 1854). A pesar de las características que posee P. paraguayensis, pensamos que no es oportuno clasificar esta especie en un nuevo género monotípico.
Proteocephalus paraguayensis, considered by Freze (1965) as a species inquirenda, is redescribed and figured. When compared with other members of the Proteocephalidea, the species shows the following morpho-anatomical characters: the vitelline follicles in a dorsal position, attached to the internal longitudinal musculature and extending into both the cortex and medulla; a characteristic formation of the uterus; the uterine stem in a cortical position and uterine branches in a medullary position; a proximal vaginal sphincter; a very elongate cirrus; and very large Mehlis' glands. The specific status of Proteocephalus paraguayensis is confirmed. Our specimens were taken from Hydrodynastes gigas (the host according to Rudin was Coluber sp.). Even though the species differs significantly from other proteocephalideans, its systematic and phylogenetic position is not yet clearly demonstrated, and it is decided to refrain from attributing it to a new genus. 相似文献
42.
43.
Christophe F. Deroanne Alain C. Colige Betty V. Nusgens Charles M. Lapiere 《Experimental cell research》1996,224(2):215
A model of collagen-inducedin vitroangiogenesis was used to investigate the modulation of expression and assembly of focal adhesion plaque-associated proteins during the process of differentiation. Human umbilical vein endothelial cells (HUVEC), first attached on an adhesive substratum (gelatin-, fibronectin-, or laminin-coated dish) or adherent collagen gel and then covered by an overlaying collagen gel, organized within 3–4 days in tube-like structures (TLS). Removing the overlaying collagen gel from fully differentiated HUVEC induced a reversion of the process and HUVEC returned to a monolayer pattern. Modulations of focal adhesion-associated proteins occurring in HUVEC during thein vitrodifferentiation process and its reversal were investigated by Western blot analysis. A significant decrease of expression of vinculin, the integrin α2subunit, talin, α-actinin, and actin was observed in TLS whereas the amount of FVIII-related antigen did not vary as compared to control monolayer cultures. During reversal, all the reduced proteins were markedly reexpressed. Human skin fibroblasts (HSF), submitted to the same experimental conditions, did not form TLS. Most of the focal adhesion proteins in HSF were similarly modulated by an overlaying collagen gel with the exception of vinculin, which was not modified. This particular protein was therefore more thoroughly investigated. In a nondifferentiated monolayer of HUVEC, a significant proportion of vinculin was organized into a detergent-resistant juxtamembranous structure (focal adhesion plaque) which disassembled early in TLS formation and reassembled during the reversal of the process. The reduction of vinculin during TLS formation was preceded by a downregulation of its mRNA while this mRNA was upregulated during reversal of the morphotype. These results suggest that the modulations of the cytoskeletal and focal adhesion proteins and more specifically of vinculin coupled to its subcellular redistribution are critical and early events in the cascade of mechanochemical signaling duringin vitroangiogenesis induced by fibrillar collagen. 相似文献
44.
Josiane Arnaud Pierre Bourlard Bernard Denis Alain E. Favier 《Biological trace element research》1996,53(1-3):129-136
This study was carried out to assess manganese (Mn) status after an acute episode of myocardial infarction. Plasma and erythrocyte
Mn concentrations were measured from admission to hospital to day 15 postadmission in 21 patients suffering from acute myocardial
infarction and in three control groups. The determination of Mn in these biological fluids was performed by electrothermal
atomic absorption spectrometry. Plasma Mn was higher (p<0.01) and erythrocyte Mn was similar in the acute myocardial infarction group compared to healthy age-matched control group.
Plasma and erythrocyte Mn remained unchanged during the 2 wk after acute myocardial infarction and were not correlated to
enzyme activities. A decrease of erythrocyte Mn with age, expressed in nmol/L, was noted (p<0.02). These results suggest that plasma and erythrocyte Mn do not provide an indication of myocardial damage. Nonetheless,
Mn status in elderly merits further attention. 相似文献
45.
46.
A reassessment of the intervention of calmodulin in the regulation of stomatal movement 总被引:5,自引:0,他引:5
Commelina cammunis L., a monocotyledonous plant whose stomata are highly sensitive to calcium ions, was used to study calmodulin (CaM) involvement in stomatal movements. CaM was detected and quantified in guard cell and mesophyll cell protoplasts by western blot and by 45 Ca2+ -overlays. CaM was found to be 3- to 7-fold more abundant on a per protein basis in guard cell than in mesophyll cell protoplasts. Numerous guard cell proteins that bind CaM in a Ca2+ -dependent manner were detected by gold-labelled CaM overlays. Using bioassays with epidermal strips, different CaM-antagonists were found to induce a net stimulation of stomatal opening in darkness or under illumination (trifluoperazine > compound 48/80 ∼ fluphenazine > W7 > W5). As CaM is frequently involved in the regulation of phosphorylation processes, the effects of different inhibitors of protein kinases on stomatal movements were studied. In red plus blue light, a promotion of the stomatal aperture was observed in the nanomolar range with K252a and KT5926 and in the micromolar range with KT5720 ≫ ML7 ∼ ML9 ≫ H7 > KN62. Only the inhibitors with a high specificity for Ca2+ -CaM dependent protein kinases (K252a, KT5926, ML7, ML9) triggered a stomatal opening in darkness and increased stomatal aperture in red plus blue light. Taken together, these data strongly suggest that a Ca2+ - or a Ca2+ -CaM-dependent protein kinase plays a central role in the calcium transduction pathway leading to the maintaining of stomatal closure. 相似文献
47.
Jacques Gervet Alain Gallo Raphael Chalmeau Muriel Soleilhavoup 《Acta biotheoretica》1996,44(1):37-57
A distinction is made between two definitions of animal cognition: the one most frequently employed in cognitive sciences considers cognition as extracting and processing information; a more phenomenologically inspired model considers it as attributing to a form of the outside world a significance, linked to the state of the animal. The respective fields of validity of these two models are discussed along with the limitations they entail, and the questions they pose to evolutionary biologists are emphasized. This is followed by a presentation of a general overview of what might be the study of the evolution of knowledge in animals. 相似文献
48.
49.
Ajoy Basak Alain Boudreault Andrew Chen Michel Chrtien Nabil G. Seidah Claude Lazure 《Journal of peptide science》1995,1(6):385-395
Antiserum against an N-terminal sequence of murine prohormone convertase-1 (mPC1) incorporating the sequence immediatley following the junction between the putative pro-region and the active enzyme was obtained. This was accomplished using the multiple antigenic peptide (MAP) approach whereupon an 8-branched polylysine core to which are grafted multiple copies of a 16 amino acid peptide representing the N-terminal sequence of mPC1 (positions 84–99) was synthesized by solid-phase Fmoc chemistry. The ensuing peptide was purified and fully characterized by RP-HPLC, 1H-NMR, amino acid composition, peptide sequencing and ion-spray mass spectrometry. The immunological properties of the resulting antibodies in detecting recombinant PC1 in both crude and purified preparations were compared with antibodies raised against a similar N-terminal segment of PC1 but using the conventioanl method of peptide–carrier protein conjugation and also developed against a C-terminal fusion protein of PC1. Our data indicate that the MAP antibody was as efficient as both the amino and carboxy-terminal antibodies in qualitative as well as quantitative analysis of PC1 encoded protein by radioimmunoassay. Following an identical approach, antibodies against other prohormone convertases like furin, PC5/6 and PACE4 were also developed and subsequently applied to a number of biochemical and immunological studies. In each case, the ease of preparation and high immunogenicity of the MAP approach were confirmed and reside in the simplicity and rapidity with which a potent and useful antiserum is obtained. 相似文献
50.
Josiane Girardie Adrien Girardie Alain Van Dorsselaer Odile Sorokine Serge Geoffre Michel Hospital Gilles Precigoux 《Journal of peptide science》1995,1(5):311-318
An original insect neurohormone of 65 residues was synthesized by the solid-phase methodology using t-Boc strategy and Boc-Val-PAM–resin. The purification, conducted by several steps of liquid chromatography having mass, polarity or charge as separative criteria, yielded the product with the correct molecular weight of 6922 Da determined by mass spectrometry. The synthetic peptide had both the same affinity for the antinative neurohormone serum and the same biological activity as the native neurohormone. 相似文献