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131.
Jane Mello Lopes Cheila de Lima Boijink Luiz Henrique Florindo Cleo Alcantara Costa Leite Ana Lúcia Kalinin William K. Milsom Francisco Tadeu Rantin 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2010,180(6):797-811
In one series of experiments, heart frequency (f
H), blood pressure (P
a), gill ventilation frequency (f
R
), ventilation amplitude (V
AMP) and total gill ventilation (V
TOT) were measured in intact jeju (Hoplerythrinus unitaeniatus) and jeju with progressive denervation of the branchial branches of cranial nerves IX (glossopharyngeal) and X (vagus) without
access to air. When these fish were submitted to graded hypoxia (water PO2 ~140, normoxia to 17 mmHg, severe hypoxia), they increased f
R
, V
AMP, V
TOT and P
a and decreased f
H. In a second series of experiments, air-breathing frequency (f
RA), measured in fish with access to the surface, increased with graded hypoxia. In both series, bilateral denervation of all
gill arches eliminated the responses to graded hypoxia. Based on the effects of internal (caudal vein, 150 μg NaCN in 0.2 mL
saline) and external (buccal) injections of NaCN (500 μg NaCN in 1.0 mL water) on f
R
, V
AMP, V
TOT, P
a and f
H we conclude that the O2 receptors involved in eliciting changes in gill ventilation and associated cardiovascular responses are present on all gill
arches and monitor the O2 levels of both inspired water and blood perfusing the gills. We also conclude that air breathing arises solely from stimulation
of branchial chemoreceptors and support the hypothesis that internal hypoxaemia is the primary drive to air breathing. 相似文献
132.
Eduardo Vilanova Cristiano Coutinho Guilherme Maia Paulo A. S. Mourão 《Cell and tissue research》2010,340(3):523-531
Marine sponges (Porifera) display an ancestral type of cell-cell adhesion, based on carbohydrate-carbohydrate interaction.
The aim of the present work was to investigate further details of this adhesion by using, as a model, the in vitro aggregation
of dissociated sponge cells. Our results showed the participation of sulfated polysaccharides in this cell-cell interaction,
as based on the following observations: (1) a variety of sponge cells contained similar sulfated polysaccharides as surface-associated
molecules and as intracellular inclusions; (2) 35S-sulfate metabolic labeling of dissociated sponge cells revealed that the majority (two thirds) of the total sulfated polysaccharide
occurred as a cell-surface-associated molecule; (3) the aggregation process of dissociated sponge cells demanded the active
de novo synthesis of sulfated polysaccharides, which ceased as cell aggregation reached a plateau; (4) the typical well-organized
aggregates of sponge cells, known as primmorphs, contained three cell types showing sulfated polysaccharides on their cell
surface; (5) collagen fibrils were also produced by the primmorphs in order to fill the extracellular spaces of their inner
portion and the external layer surrounding their entire surface. Our data have thus clarified the relevance of sulfated polysaccharides
in this system of in vitro sponge cell aggregation. The molecular basis of this system has practical relevance, since the
culture of sponge cells is necessary for the production of molecules with biotechnological applications. 相似文献
133.
Jonny E. Scherwinski-Pereira Rodrigo S. da Guedes Paulo César P. FerminoJr Tatiane L. Silva Frederico Henrique S. Costa 《In vitro cellular & developmental biology. Plant》2010,46(4):378-385
An efficient procedure has been developed for inducing somatic embryogenesis and regeneration of plants from tissue cultures
of oil palm (Elaeis guineensis Jacq.). Thin transverse sections (thin cell layer explants) of different position in the shoot apex and leaf sheath of oil
palm were cultivated in Murashige and Skoog (MS) (Physiol Plant 15:473–497, 1962) medium supplemented with 0–450 μM picloram and 2,4-D with 3.0% sucrose, 500 mg L−1 glutamine, and 0.3 g L−1 activated charcoal and gelled with 2.5 g L−1 Phytagel. Embryogenic calluses were evaluated 12 wk after inoculation. Picloram (450 μM) was effective in inducing embryogenic
calluses in 41.5% of the basal explants. Embryogenic calluses were maintained on a maturation medium composed of basal media,
plus 0.6 μM NAA and 12.30 μM 2iP, 0.3 g L−1 activated charcoal, and 500 mg L−1 glutamine, with subcultures at 4-wk intervals. Somatic embryos were converted to plants on MS medium with macro- and micronutrients
at half-strength, 2% sucrose, and 1.0 g L−1 activated charcoal and gelled with 2.5 g L−1 Phytagel. 相似文献
134.
Ana Flávia Azevedo Carvalho Maurício Boscolo Roberto da Silva Henrique Ferreira Eleni Gomes 《Journal of microbiology (Seoul, Korea)》2010,48(4):452-459
An α-glucosidase enzyme produced by the fungus Thermoascus aurantiacus CBMAI 756 was purified by ultra filtration, ammonium sulphate precipitation, and chromatography using Q Sepharose, Sephacryl
S-200, and Superose 12 columns. The apparent molecular mass of the enzyme was 83 kDa as determined in gel electrophoresis.
Maximum activity was observed at pH 4.5 at 70°C. Enzyme showed stability stable in the pH range of 3.0–9.0 and lost 40% of
its initial activity at the temperatures of 40, 50, and 60°C. In the presence of ions Na+, Ba2+, Co2+, Ni2+, Mg2+, Mn2+, Al3+, Zn2+, Ca2+ this enzyme maintained 90–105% of its maximum activity and was inhibited by Cr3+, Ag+, and Hg2+. The enzyme showed a transglycosylation property, by the release of oligosaccharides after 3 h of incubation with maltose,
and specificity for short maltooligosaccharides and α-PNPG. The Km measured for the α-glucosidase was 0.07 μM, with a Vmax of 318.0 μmol/min/mg. 相似文献
135.
Kap‐Hoon Han Yoon‐Hee Chun Bárbara De Castro Pimentel Figueiredo Frederico Marianetti Soriani Marcela Savoldi Agostinho Almeida Fernando Rodrigues Charlie Timothy Cairns Elaine Bignell Jaqueline Moisés Tobal Maria Helena S. Goldman Jong‐Hwan Kim Yong‐Sun Bahn Gustavo Henrique Goldman Márcia Eliana Da Silva Ferreira 《Molecular microbiology》2010,75(6):1372-1388
Carbon dioxide (CO2) and its hydration product bicarbonate (HCO3‐) are essential molecules in various physiological processes of all living organisms. The reversible interconversion between CO2 and HCO3‐ is in equilibrium. This reaction is slow without catalyst, but can be rapidly facilitated by Zn2+‐metalloenzymes named carbonic anhydrases (CAs). To gain an insight into the function of multiple clades of fungal CA, we chose to investigate the filamentous fungi Aspergillus fumigatus and A. nidulans. We identified four and two CAs in A. fumigatus and A. nidulans, respectively, named cafA‐D and canA‐B. The cafA and cafB genes are constitutively, strongly expressed whereas cafC and cafD genes are weakly expressed but CO2‐inducible. Heterologous expression of the A. fumigatus cafB, and A. nidulans canA and canB genes completely rescued the high CO2‐requiring phenotype of a Saccharomyces cerevisiaeΔnce103 mutant. Only the ΔcafAΔcafB and ΔcanB deletion mutants were unable to grow at 0.033% CO2, of which growth defects can be restored by high CO2. Defects in the CAs can affect Aspergilli conidiation. Furthermore, A. fumigatusΔcafA, ΔcafB, ΔcafC, ΔcafD and ΔcafAΔcafB mutant strains are fully virulent in a low‐dose murine infection. 相似文献
136.
Luiz Henrique Saes Zobiole Edicléia Aparecida Bonini Rubem Silvério de OliveiraJr. Robert John Kremer Osvaldo Ferrarese-Filho 《Acta Physiologiae Plantarum》2010,32(5):831-837
Farmers report that some glyphosate-resistant soybean varieties are visually injured by glyphosate. Glyphosate is the main
herbicide that directly affects the synthesis of secondary compounds. In this work, we evaluated the effect of increasing
rates of glyphosate on lignin and amino acid content, photosynthetic parameters and dry biomass in the early maturity group
cultivar BRS 242 GR soybean. Plants were grown in half-strength complete nutrient solution and subjected to various rates
of glyphosate either as a single or in sequential applications. All parameters evaluated were affected by increasing glyphosate
rates. The effects were more pronounced as glyphosate rates increased, and were more intense with a single total application
than sequential applications at lower rates. 相似文献
137.
Tomaz Henrique Araújo Flavio Pavla de Faria Eduardo Katchburian Edna Freymüller Haapalainen 《Acta zoologica》2010,91(4):440-446
Araújo, T.H., Faria, F.P., Katchburian, E. and Freymüller, E. (2009). Ultrastructural changes in skeletal muscle of the tail of the lizard Hemidactylus mabouia immediately following autotomy. —Acta Zoologica (Stockholm) 91 : 440–446. Although autotomy and subsequent regeneration of lizard tails has been extensively studied, there is little information available on ultrastructural changes that occur to the muscle fibers at the site of severance. Thus, in the present study, we examine the ultrastructure of the musculature of the remaining tail stump of the lizard Hemidactylus mabouia immediately after autotomy. Our results show that exposed portions of the skeletal muscle fibers of the stump that are unprotected by connective tissue bulge to produce large mushroom‐like protrusions. These exposed portions show abnormal structure but suffer no leakage of cytoplasmic contents. Many small and large vesicular structures appeared between myofibrils in the interface at this disarranged region (distal) and the other portion of the fibers that remain unchanged (proximal). These vesicles coalesce, creating a gap that leads to the release of the mushroom‐like protrusion. So, our results showed that after the macroscopic act of autotomy the muscular fibers release part of the sarcoplasm as if a second and microscopic set of autotomic events takes place immediately following the macroscopic act of autotomy. Presumably these changes pave the way for the formation of a blastema and the beginning of regeneration. 相似文献
138.
139.
140.
Aureo Banhos Bruno L. Fontes Débora Regina Yogui Mario Henrique Alves Natália Carneiro Ardente Renata Valls Lucas Mendes Barreto Lucas Damásio Átilla Colombo Ferreguetti Andréa Siqueira Carvalho Vitor Roberto Schettino Alexandre Rosa dos Santos Helena Godoy Bergallo Ana Carolina Srbek-Araujo Emilia Patrícia Medici Ariel Canena Arnaud L.J. Desbiez 《Biotropica》2020,52(3):421-426
We report 24 records of giant armadillo roadkill on Brazilian highways in the Cerrado, Pantanal and Amazon biomes illustrating that highways are a threat to this species. However, we also documented the species using underpasses, demonstrating that these structures could help to reduce the risk of roadkill for giant armadillos. 相似文献