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991.
Lucas Spohn Christiane Fichter Martin Werner Silke Lassmann 《Journal of cell communication and signaling》2016,10(1):41-47
Background: The EGF receptor is a therapeutic target in cancer cells, whereby mutations of EGFR and/or signalling members act as predictive markers. EGFR however also exhibits dynamic changes of subcellular localization, leading to STAT5 complex formation, nuclear translocation and induction of Aurora-A expression in squamous cancer cells. We previously described high EGFR and Aurora-A expression in esophageal cancer cells. Here, we investigated subcellular localization of EGFR and STAT5 in esophageal cancer cells. Results: Quantitative immunofluorescence analyses of four esophageal cancer cell lines reflecting esophageal squamous cell carcinomas (ESCC) and esophageal adenocarcinomas (EAC) revealed that the subcellular localization of EGFR was shifted from a membranous to cytoplasmic localization upon EGF-stimulation in OE21 (ESCC) cells. Thereby, EGFR in part co-localized with E-Cadherin. In parallel, phosphorylated STAT5-Tyr694 appeared to increase in the nucleus and to decrease at the cell membrane. In three additional cell lines, EGFR was only marginally (Kyse-410/ESCC; OE19/EAC) and weakly (OE33, EAC) detectable at the cell membrane. Partial co-localization of EGFR and E-Cadherin occurred in OE33 cells. Post EGF-stimulation, EGFR was detected in the cytoplasm, resembling endosomal compartments. Furthermore, OE19 and OE33 exhibited nuclear STAT5-Tyr694 phosphorylation upon EGF-stimulation. None of the four cell lines showed nuclear EGFR expression and localization. Conclusion: In contrast to other (squamous) cancer cells, activation of EGFR in esophageal squamous cancer cells does not result in nuclear translocation of EGFR. Still, the subcellular localization of EGFR may influence STAT5-associated signaling pathways in esophageal cancer cells and hence possibly also the responses to ErbB, respective EGFR-targeted therapies. 相似文献
992.
Naresh Loudya Douglas P F Maffei Jocelyn Bdard Sabri Mohd Ali Paul F Devlin R Paul Jarvis Enrique Lpez-Juez 《The Plant cell》2022,34(8):3028
Chloroplast biogenesis requires synthesis of proteins in the nucleocytoplasm and the chloroplast itself. Nucleus-encoded chloroplast proteins are imported via multiprotein translocons in the organelle’s envelope membranes. Controversy exists around whether a 1-MDa complex comprising TIC20, TIC100, and other proteins constitutes the inner membrane TIC translocon. The Arabidopsis thaliana cue8 virescent mutant is broadly defective in plastid development. We identify CUE8 as TIC100. The tic100cue8 mutant accumulates reduced levels of 1-MDa complex components and exhibits reduced import of two nucleus-encoded chloroplast proteins of different import profiles. A search for suppressors of tic100cue8 identified a second mutation within the same gene, tic100soh1, which rescues the visible, 1 MDa complex-subunit abundance, and chloroplast protein import phenotypes. tic100soh1 retains but rapidly exits virescence and rescues the synthetic lethality of tic100cue8 when retrograde signaling is impaired by a mutation in the GENOMES UNCOUPLED 1 gene. Alongside the strong virescence, changes in RNA editing and the presence of unimported precursor proteins show that a strong signaling response is triggered when TIC100 function is altered. Our results are consistent with a role for TIC100, and by extension the 1-MDa complex, in the chloroplast import of photosynthetic and nonphotosynthetic proteins, a process which initiates retrograde signaling.Complementary mutations in TIC100 of the chloroplast inner envelope membrane cause reductions or corrective improvements in chloroplast protein import, and highlight a signaling role.IN A NUTSHELLBackground: Plants harvest energy from the sun and CO2 from the air and convert them into the energy-rich molecules they, and eventually us, are made of. Plants do this, photosynthesis, in bodies called chloroplasts inside their cells. Chloroplasts, made of protein and membrane material, were, before plants evolved, free-living bacteria, but the synthesis of most of their proteins occurs outside them, using information carried by the cell’s nuclear DNA, so most proteins have to be brought into developing chloroplasts, across the double membrane surrounding them, through dedicated, selective channels, formed by TOC (outer) and TIC (inner envelope) proteins. The identity of those channels matters as it helps determine versions of chloroplasts suited for particular environments. Which TIC proteins constitute the inner envelope channel has been a matter of controversy.Question: A mutant Arabidopsis plant called cue8 is slow-to-green (young leaves begin almost white) and shows delayed chloroplast and plant development. We looked for the molecular identity of the CUE8 gene. We also caused further mutations in this mutant and searched whether any corrected the defects in cue8.Findings: We found the mutated gene causing the cue8 defects is the TIC100 gene. This is one essential component of the “TIC 1-MDa complex,” one of the two versions of the TIC import complex under debate. That complex is made of several proteins, all present at reduced levels in cue8. In laboratory assays in which proteins are imported into isolated chloroplasts, cue8 performed worse than normal plants for a photosynthetic and a housekeeping chloroplast protein. A corrective, “suppressor” mutant was identified, and it carried a second mutation in TIC100, one physically complementary to the first one. Both the single and the double (suppressed) mutant still were slow-to-green, which evidences a signaling role for import defects to the nucleus, making photosynthetic genes active or not.Next steps: Surprisingly the grasses, including the cereals, have one core protein of the TIC 1 MDa complex but not the rest (including TIC100). We don’t know how their TIC channels operate. We also need to learn how the information on the defect in protein import, which occurs at the chloroplast envelope, is relayed to the cell’s nucleus (but we do have some clues). 相似文献
993.
994.
Se Ryun Kwon Yue Jai Kang Dong Jin Lee Eun Hye Lee Yoon Kwon Nam Sung Koo Kim Ki Hong Kim 《Molecular biotechnology》2009,42(2):154-159
Vibrio anguillarum ghosts (VAG) were generated, for the first time, using a conjugation vector containing a ghost bacteria inducing cassette,
pRK-λPR-cI-Elysis, in which the expression of PhiX174 lysis gene E was controlled by the P
R
/cI regulatory system of lambda phage. By scanning electron microscopy, holes ranging 80–200 nm in diameter were observed in
the VAG. To avoid the presence of bacterial genomic DNA and an antibiotic resistance gene in the final VAG product, we constructed
a new dual vector, pRK-λPR-cI-E-SNA, containing the E-mediated lysis cassette and the staphylococcal nuclease A (SNA)-mediated DNA degradation cassette, and generated safety-enhanced VAG for use as a fish vaccine. 相似文献
995.
Kai-Shu Ling Karen R. Harris Jenelle D. F. Meyer Amnon Levi Nihat Guner Todd C. Wehner Abdelhafid Bendahmane Michael J. Havey 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,120(1):191-200
Zucchini yellow mosaic virus (ZYMV) is one of the most economically important potyviruses infecting cucurbit crops worldwide. Using a candidate gene approach,
we cloned and sequenced eIF4E and eIF(iso)4E gene segments in watermelon. Analysis of the nucleotide sequences between the
ZYMV-resistant watermelon plant introduction PI 595203 (Citrullus lanatus var. lanatus) and the ZYMV-susceptible watermelon cultivar ‘New Hampshire Midget’ (‘NHM’) showed the presence of single nucleotide polymorphisms
(SNPs). Initial analysis of the identified SNPs in association studies indicated that SNPs in the eIF4E, but not eIF(iso)4E,
were closely associated to the phenotype of ZYMV-resistance in 70 F2 and 114 BC1R progenies. Subsequently, we focused our efforts in obtaining the entire genomic sequence of watermelon eIF4E. Three SNPs
were identified between PI 595203 and NHM. One of the SNPs (A241C) was in exon 1 and the other two SNPs (C309A and T554G)
were in the first intron of the gene. SNP241 which resulted in an amino acid substitution (proline to threonine) was shown
to be located in the critical cap recognition and binding area, similar to that of several plant species resistance to potyviruses.
Analysis of a cleaved amplified polymorphism sequence (CAPS) marker derived from this SNP in F2 and BC1R populations demonstrated a cosegregation between the CAPS-2 marker and their ZYMV resistance or susceptibility phenotype.
When we investigated whether such SNP mutation in the eIF4E was also conserved in several other PIs of C. lanatus var. citroides, we identified a different SNP (A171G) resulting in another amino acid substitution (D71G) from four ZYMV-resistant C. lanatus var. citroides (PI 244018, PI 482261, PI 482299, and PI 482322). Additional CAPS markers were also identified. Availability of all these
CAPS markers will enable marker-aided breeding of watermelon for ZYMV resistance. 相似文献
996.
Peter Roessingh Sen Xu Steph B. J. Menken 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2007,193(6):635-647
In lepidopterous larvae the maxillary palps contain a large portion of the sensory equipment of the insect. Yet, knowledge
about the sensitivity of these cells is limited. In this paper a morphological, behavioral, and electrophysiological investigation
of the maxillary palps of Yponomeuta cagnagellus (Lepidoptera: Yponomeutidae) is presented. In addition to thermoreceptors, CO2 receptors, and gustatory receptors, evidence is reported for the existence of two groups of receptor cells sensitive to plant
volatiles. Cells that are mainly sensitive to (E)-2-hexenal and hexanal or to (Z)-3-hexen-1-ol and 1-hexanol were found. Interestingly, a high sensitivity for benzaldehyde was also found. This compound
is not known to be present in Euonymus europaeus, the host plant of the monophagous Yponomeuta cagnagellus, but it is a prominent compound in Rosaceae, the presumed hosts of the ancestors of Y. cagnagellus. To elucidate the evolutionary history of this sensitivity, and its possible role in host shifts, feeding responses of three
Yponomeuta species to benzaldehyde were investigated. The results confirm the hypothesis that the sensitivity to benzaldehyde evolved
during the ancestral shift from Celastraceae to Rosaceae and can be considered an evolutionary relict, retained in the recently
backshifted Celastraceae-specialist Y. cagnagellus. 相似文献
997.
Tsuji S Ueda K Nishiyama T Hasebe M Yoshikawa S Konagaya A Nishiuchi T Yamaguchi K 《Journal of plant research》2007,120(2):281-290
We determined the complete nucleotide sequence of the chloroplast genome of Selaginella uncinata, a lycophyte belonging to the basal lineage of the vascular plants. The circular double-stranded DNA is 144,170 bp, with
an inverted repeat of 25,578 bp separated by a large single copy region (LSC) of 77,706 bp and a small single copy region
(SSC) of 40,886 bp. We assigned 81 protein-coding genes including four pseudogenes, four rRNA genes and only 12 tRNA genes.
Four genes, rps15, rps16, rpl32 and ycf10, found in most chloroplast genomes in land plants were not present in S. uncinata. While gene order and arrangement of the chloroplast genome of another lycophyte, Hupertzia lucidula, are almost the same as those of bryophytes, those of S. uncinata differ considerably from the typical structure of bryophytes with respect to the presence of a unique 20 kb inversion within
the LSC, transposition of two segments from the LSC to the SSC and many gene losses. Thus, the organization of the S. uncinata chloroplast genome provides a new insight into the evolution of lycophytes, which were separated from euphyllophytes approximately
400 million years ago.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
998.
Ascorbate (AsA) plays a fundamental role in redox homeostasis in plants and animals, primarily by scavenging reactive oxygen
species. Three genes, representing diverse steps putatively involved in plant AsA biosynthesis pathways, were cloned and independently
expressed in Solanum lycopersicum (tomato) under the control of the CaMV 35S promoter. Yeast-derived GDP-mannose pyrophosphorylase (GMPase) and arabinono-1,4-lactone oxidase (ALO), as well as myo-inositol oxygenase 2 (MIOX2) from Arabidopsis thaliana, were targeted. Increases in GMPase activity were concomitant with increased AsA levels of up to 70% in leaves, 50% in green
fruit, and 35% in red fruit. Expression of ALO significantly pulled biosynthetic flux towards AsA in leaves and green fruit by up to 54 and 25%, respectively. Changes in
AsA content in plants transcribing the MIOX2 gene were inconsistent in different tissue. On the other hand, MIOX activity was strongly correlated with cell wall uronic
acid levels, suggesting that MIOX may be a useful tool for the manipulation of cell wall composition. In conclusion, the Smirnoff–Wheeler
pathway showed great promise as a target for biotechnological manipulation of ascorbate levels in tomato. 相似文献
999.
Four different bacterial isolates obtained from a stable bacterial consortium were capable of utilizing pentachlorophenol
(PCP) as sole carbon and energy source. The consortium was developed by continuous enrichment in the chemostat. The degradation
of PCP by bacterial strain was preceded through an oxidative route as indicated by accumulation of tetrachloro-ρ-hydroquinone
and dichlorohydroquinone as determined by high performance liquid chromatography (HPLC). Among the four isolates, Pseudomonas fluorescens exhibited maximum degradation capability and enzyme production. PCP-monooxygenase enzyme was extracted from culture extract
and fractionated by DEAE-cellulose ion exchange chromatography. The molecular weight of the enzyme, purified from Pseudomonas fluorescens, determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography was
found to be 24,000 Da.
Received: 22 July 2002 / Accepted: 23 September 2002 相似文献
1000.
Don A. Driscoll Annabel L. Smith Samantha Blight John Maindonald 《Biodiversity and Conservation》2012,21(6):1607-1625
Altered fire regimes are a driver of biodiversity decline. To plan effective management, we need to know how species are influenced
by fire and to develop theory describing fire responses. Animal responses to fire are usually measured using methods that
rely on animal activity, but animal activity may vary with time since fire, potentially biasing results. Using a novel approach
for detecting bias in the pit-fall trap method, we found that leaf-litter dependent reptiles were more active up to 6 weeks
after fire, giving a misleading impression of abundance. This effect was not discovered when modelling detectability with
zero-inflated binomial models. Two species without detection bias showed early-successional responses to time since fire,
consistent with a habitat-accommodation succession model. However, a habitat specialist did not have the predicted low abundance
after fire due to increased post-fire movement and non-linear recovery of a key habitat component. Interactions between fire
and other processes therefore must be better understood to predict reptile responses to changing fire-regimes. We conclude
that there is substantial bias when trapping reptiles after fire, with species that are otherwise hard to detect appearing
to be abundant. Studies that use a survey method based on animal activity such as bird calls or animal movements, likely face
a similar risk of bias when comparing recently-disturbed with control sites. 相似文献