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41.
C. Salazar‐Parra J. Aguirreolea M. Sánchez‐Díaz J.J. Irigoyen F. Morales 《The Annals of applied biology》2012,161(3):277-292
Photosynthesis in C3 plants is CO2 limited and therefore any increase in Rubisco carboxylation substrate may increase net CO2 fixation, unless plants experience acclimation or other limitations. These aspects are largely unexplored in grapevine. Photosynthesis analysis was used to assess the stomatal, mesophyll, photochemical and biochemical contributions to the decreasing photosynthesis observed in Tempranillo grapevines (Vitis vinifera) from veraison to ripeness, modulated by CO2, temperature and water availability. Photosynthesis and photosystem II photochemistry decreased from veraison to ripeness. The elevated CO2 and temperature increased photosynthesis, but transiently, in both well irrigated (WI) and water‐stressed plants. Photosynthetic rates were maxima 1 week after the start of elevated CO2 and temperature treatments, but differences with treatments of ambient conditions disappeared with time. There were not marked changes in leaf water status, leaf chlorophyll or leaf protein that could limit photosynthesis at ripeness. Leaf total soluble sugars remained at ripeness as high as 2 weeks after the start of treatments. On the other hand, and as expected, CO2 diffusional limitations impaired photosynthesis in grapevine plants grown under water scarcity, stomatal and mesophyll conductances to CO2 decreased and in turn low chloroplastic CO2 concentrations limited photosynthetic CO2 fixation. In summary, photochemistry and photosynthesis from veraison to ripeness in Tempranillo grapevine were dominated by a developmental‐related decreasing trend that was only transiently influenced by elevated CO2 concentrations. 相似文献
42.
Autonomous replication sequences in an extrachromosomal element of a pathogenic Entamoeba histolytica. 总被引:1,自引:1,他引:1 下载免费PDF全文
Entamoeba histolytica possesses a 24.5 kilobase plasmid-like molecule which encodes for the organism's ribosomal RNAs. Sequence analysis of this extrachromosomal element revealed the presence of AT rich sequences which show homology to the origin of replication of other lower eucaryotes. An 802 bp fragment containing these sequences was cloned into a yeast shuttle vector lacking the origin of replication and the construct tested for its ability to replicate autonomously in yeast. Mitotic stability tests as well as evidence for plasmid maintenance indicate that the transformed cells contained self-replicating episomes and not stably integrated molecules. The nucleotide sequence of this ARS-containing fragment is presented. 相似文献
43.
Gloria Salazar Stephanie Zlatic Branch Craige Andrew A. Peden Jan Pohl Victor Faundez 《The Journal of biological chemistry》2009,284(3):1790-1802
The Hermansky-Pudlak syndrome is a disorder affecting endosome sorting.
Disease is triggered by defects in any of 15 mouse gene products, which are
part of five distinct cytosolic molecular complexes: AP-3, homotypic fusion
and vacuole protein sorting, and BLOC-1, -2, and -3. To identify molecular
associations of these complexes, we used in vivo cross-linking
followed by purification of cross-linked AP-3 complexes and mass spectrometric
identification of associated proteins. AP-3 was co-isolated with BLOC-1,
BLOC-2, and homotypic fusion and vacuole protein sorting complex subunits;
clathrin; and phosphatidylinositol-4-kinase type II α (PI4KIIα).
We previously reported that this membrane-anchored enzyme is a regulator of
AP-3 recruitment to membranes and a cargo of AP-3 (Craige, B.,
Salazar, G., and Faundez, V. (2008) Mol. Biol.
Cell
19,1415
-1426). Using cells deficient
in different Hermansky-Pudlak syndrome complexes, we identified that BLOC-1,
but not BLOC-2 or BLOC-3, deficiencies affect PI4KIIα inclusion into
AP-3 complexes. BLOC-1, PI4KIIα, and AP-3 belong to a tripartite
complex, and down-regulation of either PI4KIIα, BLOC-1, or AP-3
complexes led to similar LAMP1 phenotypes. Our analysis indicates that BLOC-1
complex modulates the association of PI4KIIα with AP-3. These results
suggest that AP-3 and BLOC-1 act, either in concert or sequentially, to
specify sorting of PI4KIIα along the endocytic route.Membranous organelles along the exocytic and endocytic pathways are each
defined by unique lipid and protein composition. Vesicle carriers communicate
and maintain the composition of these organelles
(2). Consequently defining the
machineries that specify vesicle formation, composition, and delivery are
central to understanding membrane protein traffic. Generally vesicle
biogenesis uses multiprotein cytosolic machineries to select membrane
components for inclusion in nascent vesicles
(2,
3). Heterotetrameric adaptor
complexes (AP-1 to AP-4) are critical to generate vesicles of specific
composition from the different organelles constituting the exocytic and
endocytic routes
(2-4).The best understood vesicle formation machinery in mammalian cells is the
one organized around the adaptor complex AP-2
(5). This complex generates
vesicles from the plasma membrane using clathrin. Our present detailed
understanding of AP-2 vesicle biogenesis mechanisms and interactions emerged
from a combination of organellar and in vitro binding proteomics
analyses together with the study of binary interactions in cell-free systems
(5-9).
In contrast, the vesicle biogenesis pathways controlled by AP-3 are far less
understood. AP-3 functions to produce vesicles that traffic selected membrane
proteins from endosomes to lysosomes, lysosome-related organelles, or synaptic
vesicles
(10-13).
AP-3 is one of the protein complexes affected in the Hermansky-Pudlak syndrome
(HPS;3 Online
Mendelian Inheritance in Man (OMIM) 203300). So far, mutations in any of 15
mouse or eight human genes trigger a common syndrome. This syndrome
encompasses defects that include pigment dilution, platelet dysfunction,
pulmonary fibrosis, and occasionally neurological phenotypes
(14,
15). All forms of HPS show
defective vesicular biogenesis or trafficking that affects lysosomes,
lysosome-related organelles (for example melanosomes and platelet dense
granules), and, in some of them, synaptic vesicles
(11-13).
Most of the 15 HPS loci encode polypeptides that assemble into five distinct
molecular complexes: the adaptor complex AP-3, HOPS, and the BLOC complexes 1,
2, and 3 (14). Recently binary
interactions between AP-3 and BLOC-1 or BLOC-1 and BLOC-2 suggested that
arrangements of these complexes could regulate membrane protein targeting
(16). Despite the abundance of
genetic deficiencies leading to HPS and genetic evidence that HPS complexes
may act on the same pathway in defined cell types
(17), we have only a partial
picture of protein interactions organizing these complexes and how they might
control membrane protein targeting.In this study, we took advantage of cell-permeant and reversible
cross-linking of HPS complexes followed by their immunoaffinity purification
to identify novel molecular interactions. Cross-linked AP-3 co-purified with
BLOC-1, BLOC-2, HOPS, clathrin, and the membrane protein PI4KIIα. We
previously identified PI4KIIα as a cargo and regulator of AP-3
recruitment to endosomes (1,
18). Using mutant cells
deficient in either individual HPS complexes or a combination of them, we
found that BLOC-1 facilitates the interaction of AP-3 and PI4KIIα. Our
studies demonstrate that subunits of four of the five HPS complexes co-isolate
with AP-3. Moreover BLOC-1, PI4KIIα, and AP-3 form a tripartite complex
as demonstrated by sequential co-immunoprecipitations as well as by similar
LAMP1 distribution phenotypes induced by down-regulation of components of this
tripartite complex. Our findings indicate that BLOC-1 complex modulates the
recognition of PI4KIIα by AP-3. These data suggest that AP-3, either in
concert or sequentially with BLOC-1, participates in the sorting of common
membrane proteins along the endocytic route. 相似文献
44.
45.
Juan A. Pajares Gonzalo Álvarez David R. Hall Paul Douglas Felix Centeno Nieves Ibarra Martin Schroeder Stephen A. Teale Zhiying Wang Shanchun Yan Jocelyn G. Millar Lawrence M. Hanks 《Entomologia Experimentalis et Applicata》2013,149(2):118-127
The small white‐marmorated longicorn beetle, Monochamus sutor (L.) (Coleoptera: Cerambycidae), is widely distributed throughout Europe and Asia. It is a potential vector of the pine wood nematode, Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle, the causal agent of the devastating pine wilt disease. Volatiles were collected from both male and female beetles after maturation feeding. In analyses of these collections using gas chromatography (GC) coupled to mass spectrometry, a single male‐specific compound was detected and identified as 2‐(undecyloxy)‐ethanol. In analyses by GC coupled to electroantennography the only consistent responses from both female and male antennae were to this compound. Trapping tests were carried out in Spain, Sweden, and China. 2‐(Undecyloxy)‐ethanol was attractive to both male and female M. sutor beetles. A blend of the bark beetle pheromones ipsenol, ipsdienol, and 2‐methyl‐3‐buten‐2‐ol was also attractive to both sexes in Spain and Sweden, and further increased the attractiveness of the 2‐(undecyloxy)‐ethanol. The host plant volatiles α‐pinene, 3‐carene, and ethanol were weakly attractive, if at all, in all three countries and did not significantly increase the attractiveness of the blend of 2‐(undecyloxy)‐ethanol and bark beetle pheromones. 2‐(Undecyloxy)‐ethanol is thus proposed to be the major, if not only, component of the male‐produced aggregation pheromone of M. sutor, and its role is discussed. This compound has been reported as a pheromone of several other Monochamus species and is another example of the parsimony that seems to exist among the pheromones of many of the Cerambycidae. Traps baited with 2‐(undecyloxy)‐ethanol and bark beetle pheromones should be useful for monitoring and control of pine wilt disease, should M. sutor be proven to be a vector of the nematode. 相似文献
46.
47.
Minerva Martínez-Alfaro Gonzalo Ramírez-García Silvia Gutiérrez-Granados Yolanda Alcaraz-Contreras Marco-Alonso Gallegos-Corona G. Zaldivar Lelo de Larrea Alfonso Cárabez-Trejo 《Journal of trace elements in medicine and biology》2013,27(4):364-369
Exposure to lead induces oxidative stress and renal damage. Although most forms of oxidative stress are characterized by simultaneous elevation of nitrogen and oxidative species, lead-induced oxidative stress is unusual in that it is associated with a reduction in nitric oxide (NO) levels in the kidney. The role of NO in kidney injury is controversial; some studies suggest that it is associated with renal injury, whereas others show that it exerts protective effects. Concentration-dependent effects have also been proposed, linking low levels with vasodilatation and high levels with toxicity. The aim of this study was to evaluate the effects of melatonin co-exposure on the lead-induced reduction in renal NO levels. We found that sub-acute intraperitoneal administration of 10 mg/kg/day of lead for 15 days induced toxic levels of lead in the blood and caused renal toxicity (pathological and functional). Under our experimental conditions, lead induced an increase in lipid peroxidation and a decrease in NO. Melatonin co-treatment decreased lead-induced oxidative stress (peroxidation level) and toxic effects on kidneys without altering the lead-induced reduction in renal NO. These results suggest that, in our experimental model, the reduction in renal NO levels by lead exposure is not the only responsible factor for lead-induced kidney damage. 相似文献
48.
SongTing Shi Jie Cai David J. J. de Gorter Gonzalo Sanchez-Duffhues Dwi U. Kemaladewi Willem M. H. Hoogaars Annemieke Aartsma-Rus Peter A. C. ’t Hoen Peter ten Dijke 《PloS one》2013,8(7)
Fibrodysplasia ossificans progressiva (FOP) is a rare heritable disease characterized by progressive heterotopic ossification of connective tissues, for which there is presently no definite treatment. A recurrent activating mutation (c.617G→A; R206H) of activin receptor-like kinase 2 (ACVR1/ALK2), a BMP type I receptor, has been shown as the main cause of FOP. This mutation constitutively activates the BMP signaling pathway and initiates the formation of heterotopic bone. In this study, we have designed antisense oligonucleotides (AONs) to knockdown mouse ALK2 expression by means of exon skipping. The ALK2 AON could induce exon skipping in cells, which was accompanied by decreased ALK2 mRNA levels and impaired BMP signaling. In addition, the ALK2 AON potentiated muscle differentiation and repressed BMP6-induced osteoblast differentiation. Our results therefore provide a potential therapeutic approach for the treatment of FOP disease by reducing the excessive ALK2 activity in FOP patients. 相似文献
49.
Gregory Bonito Matthew E. Smith Michael Nowak Rosanne A. Healy Gonzalo Guevara Efren Cázares Akihiko Kinoshita Eduardo R. Nouhra Laura S. Domínguez Leho Tedersoo Claude Murat Yun Wang Baldomero Arroyo Moreno Donald H. Pfister Kazuhide Nara Alessandra Zambonelli James M. Trappe Rytas Vilgalys 《PloS one》2013,8(1)
Truffles have evolved from epigeous (aboveground) ancestors in nearly every major lineage of fleshy fungi. Because accelerated rates of morphological evolution accompany the transition to the truffle form, closely related epigeous ancestors remain unknown for most truffle lineages. This is the case for the quintessential truffle genus Tuber, which includes species with socio-economic importance and esteemed culinary attributes. Ecologically, Tuber spp. form obligate mycorrhizal symbioses with diverse species of plant hosts including pines, oaks, poplars, orchids, and commercially important trees such as hazelnut and pecan. Unfortunately, limited geographic sampling and inconclusive phylogenetic relationships have obscured our understanding of their origin, biogeography, and diversification. To address this problem, we present a global sampling of Tuberaceae based on DNA sequence data from four loci for phylogenetic inference and molecular dating. Our well-resolved Tuberaceae phylogeny shows high levels of regional and continental endemism. We also identify a previously unknown epigeous member of the Tuberaceae – the South American cup-fungus Nothojafnea thaxteri (E.K. Cash) Gamundí. Phylogenetic resolution was further improved through the inclusion of a previously unrecognized Southern hemisphere sister group of the Tuberaceae. This morphologically diverse assemblage of species includes truffle (e.g. Gymnohydnotrya spp.) and non-truffle forms that are endemic to Australia and South America. Southern hemisphere taxa appear to have diverged more recently than the Northern hemisphere lineages. Our analysis of the Tuberaceae suggests that Tuber evolved from an epigeous ancestor. Molecular dating estimates Tuberaceae divergence in the late Jurassic (∼156 million years ago), with subsequent radiations in the Cretaceous and Paleogene. Intra-continental diversification, limited long-distance dispersal, and ecological adaptations help to explain patterns of truffle evolution and biodiversity. 相似文献
50.
Rojas Wastavino G Tato Zaldívar P Solano Galvez S Herrera Montalvo L Gutiérrez Quiroz M Salazar Schettino PM 《Boletín chileno de parasitología》1999,54(3-4):57-62
Due to the importance of cysticercosis in Mexico and Latin America and to the fact that in the last years another mechanism of infection for this disease has been proposed, i.e. through postoncospheres and immunosuppression of the host, we have considered relevant to perform the present work, which consisted in assessing the immune response induced by dexamethasone as well as that produced by parasites in pigs infected with T. solium eggs, or postoncosphere-infected, and in postoncosphere-infected and dexamethasone-treated animals. We used 10 recently weaned pigs, three were used as controls, two of them without the drug and one with it; two were infected with T. solium eggs; five with postoncospheres receiving also dexamethasone three of them. We evaluated the humoral response against parasite antigen using indirect haemagglutination (IH) and ELISA methods. Results of the immune humoral response revealed titres of up to 1:128 in T. solium eggs infected animals, of 1:16 in postoncosphere infected animals, and of 1:32 towards the end of the experiment in postoncosphere plus dexamethasone animals. Absorbance titres with ELISA confirmed these findings. Data obtained by IH show that the antibody titres of the pigs challenged with postoncospheres and postoncospheres plus dexamethasone are positive as compared to the titres obtained in the pigs infected with T. solium eggs. Results from the ELISA confirmed this finding, since, from weeks 14 to 17, the pigs became positive, behaving as those pigs that developed cysticercosis. This is relevant as it indicates that the antiposcosphere antibodies recognized antigens of T. solium larvae. 相似文献