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1.
Yi-Hua Wu Chia-Pei Chang Chin-I Chien Yi-Kuan Tseng Chien-Chia Wang 《Molecular and cellular biology》2013,33(17):3515-3523
The yeast Saccharomyces cerevisiae possesses two distinct glycyl-tRNA synthetase (GlyRS) genes: GRS1 and GRS2. GRS1 is dually functional, encoding both cytoplasmic and mitochondrial activities, while GRS2 is dysfunctional and not required for growth. The protein products of these two genes, GlyRS1 and GlyRS2, are much alike but are distinguished by an insertion peptide of GlyRS1, which is absent from GlyRS2 and other eukaryotic homologues. We show that deletion or mutation of the insertion peptide modestly impaired the enzyme''s catalytic efficiency in vitro (with a 2- to 3-fold increase in Km and a 5- to 8-fold decrease in kcat). Consistently, GRS2 can be conveniently converted to a functional gene via codon optimization, and the insertion peptide is dispensable for protein stability and the rescue activity of GRS1 at 30°C in vivo. A phylogenetic analysis further showed that GRS1 and GRS2 are paralogues that arose from a gene duplication event relatively recently, with GRS1 being the predecessor. These results indicate that GlyRS2 is an active enzyme essentially resembling the insertion peptide-deleted form of GlyRS1. Our study suggests that the insertion peptide represents a novel auxiliary domain, which facilitates both productive docking and catalysis of cognate tRNAs. 相似文献
2.
C. S. Lin M. C. Tseng P. I. Hong W. C. Chang 《In vitro cellular & developmental biology. Plant》2006,42(4):331-335
Summary Inflorescence proliferation is a plant tissue culture technique that, can be used to obtain in vitro inflorescences year-round without the intervening development of vegetative organs. In this study, we used albino mutant
inflorescences of Dendrocalamus latiflorus as the original explant material to investigate, the effect of plant growth regulators on long-term inflorescence proliferation.
The albino inflorescences proliferated on solidified Murashige and Skoog (MS) basal medium supplemented with thidiazuron (TDZ),
and the optimal concentration for successful long-term inflorescence proliferation was 0.45 μM TDZ. A combination of α-naphthaleneacetic acid (NAA) with 0.45 μM TDZ inhibited the inflorescence proliferation. Inflorescences cultured on a TDZ-free medium supplemented with 26.82 μM NAA rooted in 21 d, vegetative shoots formed by 42 d and, in one case, flowering occurred after 63 d. The auxins 2,4-dichlorophenoxyacetic
acid (2,4-D, 4.52 μM) and pieloram (4.14 μM) induced shoot formation. The protocol described can be used to produce large numbers of mutant inflorescences within a relatively
short period of time. 相似文献
3.
R E Loomis C C Tseng E J Bergey M J Levine 《International journal of peptide and protein research》1988,32(2):130-140
The amino acid sequence G(1)-P(2)-P(3)-P(4)-H(5)-P(6)-G(7)-K(8)-P(9) occurs twice in the proline-rich glycoprotein (PRG) found in human parotid saliva. As part of our efforts to elucidate the structure-function relationships of PRG, this nonapeptide sequence (PRG9) was synthesized for the purpose of conformational analyses by high-resolution proton n.m.r. spectroscopy and computer-modeling. The empirical n.m.r. spectrum differed from the simulated spectrum in that the overall chemical shift locations were displaced from their random coil positions and the five proline residues had non-degenerate C alpha H alpha protons. Other n.m.r. data indicated that no intramolecular hydrogen-bonding was present in the PRG. In conjunction with X-ray crystallographic data on a triproline-containing model compound (Kartha, g., Ashida, T. & Kakudo, M. (1974) Acta Cryst. B30, 1861-1866), four energy-minimized PRG9 structures were obtained. Two of the structures were energetically unfavorable, while the other two conformations were reasonable. The two most likely structures gave all prolines an S-type ring pucker, the P(2)-P(3)-P(4) sequence as a poly-L-proline II helix, the H(5) phi = -90.3 degrees, P(6) and P(9) with trans peptide bond orientation, G(7) in an extended state, and the K(8) phi = -93.2 degrees or -146.8 degrees for structures #1 and #2, respectively. 相似文献
4.
Yu-Chi Su Goutham Venkata Naga Davuluri Cheng-Hao Chen Dong-Che Shiau Chien-Chin Chen Chia-Ling Chen Yee-Shin Lin Chih-Peng Chang 《PloS one》2016,11(2)
Hepatocellular carcinoma (HCC) is one of the most common cancers in Taiwan. Although chemotherapy is the primary treatment for HCC patients, drug resistance often leads to clinical failure. Galectin-1 is a beta-galactoside binding lectin which is up-regulated in HCC patients and promotes tumor growth by mediating cancer cell adhesion, migration and proliferation, but its role in chemoresistance of HCC is poorly understood. In this study we found that galectin-1 is able to lead to chemoresistance against cisplatin treatment, and subsequent inhibition has reversed the effect of cell death in HCC cells. Moreover, galectin-1 was found to induce autophagic flux in HCC cells. Inhibition of autophagy by inhibitors or knockdown of Atg5 cancels galectin-1-induced cisplatin resistance in HCC cells. Increase of mitophagy triggered by galectin-1 was found to reduce the mitochondrial potential loss and apoptosis induced by cisplatin treatment. Finally, using an in situ hepatoma mouse model, we clearly demonstrated that inhibition of galectin-1 by thiodigalactoside could significantly augment the anti-HCC effect of cisplatin. Taken together, our findings offer a new insight into the chemoresistance galectin-1 causes against cisplatin treatment, and points to a potential approach to improve the efficacy of cisplatin in the treatment of HCC patients. 相似文献
5.
The complete nucleotide sequence of the mitochondrial (mt) genome was determined for specimens of the coral species Montipora
cactus (Bernard 1897) and Anacropora
matthai (Pillai 1973), representing two morphologically distinct genera of the family Acroporidae. These sequences were compared
with the published mt genome sequence for the confamilial species, Acropora tenuis (Dana 1846). The size of the mt genome was 17,887 bp and 17,888 bp for M. cactus and A. matthai. Gene content and organization was found to be very similar among the three Acroporidae mt genomes with a group I intron
occurring in the NADH dehyrogenase 5 (nad5) gene. The intergenic regions were also similar in length among the three corals. The control region located between the
small ribosomal RNA (ms) and the cytochrome oxidase 3 (cox3) gene was significantly smaller in M. cactus and A. matthai (both 627 bp) than in A. tenuis (1086 bp). Only one set of repeated sequences was identified at the 3′-end of the control regions in M. cactus and A. matthai. A lack of the abundant repetitive elements which have been reported for A. tenuis, accounts for the relatively short control regions in M. cactus and A. matthai. Pairwise distances and relative rate analyses of 13 protein coding genes, the group I intron and the largest intergenic
region, igr3, revealed significant differences in the rate of molecular evolution of the mt genome among the three species, with an extremely
slow rate being seen between Montipora and Anacropora. It is concluded that rapid mt genome evolution is taking place in genus Acropora relative to the confamilial genera Montipora and Anacropora although all are within the relatively slow range thought to be typical of Anthozoa. 相似文献
6.
7.
Ectopic Expression of the Tetratricopeptide Repeat Domain of SPINDLY Causes Defects in Gibberellin Response 下载免费PDF全文
The SPINDLY (SPY) protein of Arabidopsis is a negative regulator of gibberellin (GA) response. The SPY protein has 10 copies of the tetratricopeptide repeat (TPR) at the N terminus. TPR motifs function as protein-protein interaction domains. Several spy alleles are affected only in the TPR region suggesting that protein-protein interactions mediated by this domain are important for proper GA signaling. We have used a reverse genetics approach to further investigate the role of the TPR domain. The TPR domain of SPY was overexpressed in wild-type, gai, and spy plants. Expression of the TPR domain alone is not sufficient to rescue spy mutants. Expression of the TPR domain in a wild-type background produces phenotypes similar to those caused by loss-of-function spy mutants including resistance to GA biosynthesis inhibitors, short hypocotyl length, and early flowering. The dwarfing of the floral shoot internodes caused by the gai mutation was suppressed by expression of the TRP domain. Expression of the TPR domain had no effect on the abundance of endogenous SPY mRNA. The TPR domain was found to interact with SPY both in vitro and in yeast two-hybrid assays. These data indicate that the TPR domain of SPY can participate in protein-protein interactions and that these interactions are important for the proper functioning of SPY. 相似文献
8.
The ultrastructure of the pineal organ was studied in the tropical megachiropteran Rousettus leschenaulti. The pineal lies deep beneath the hemispheres adjacent to the third ventricle and is traversed by the habenular commissure anteriorly. Its parenchyma consists of a uniform population of light and occasional dark pinealocytes which appear to differ only in the degree of cytoplasmic staining. Pinealocytes are characterized by well developed Golgi bodies associated with numerous small vesicles, many mitochondria and polyribosomes, and frequent subsurface cisternae. Lipid droplets and elements of smooth endoplasmic reticulum are scant. Cisternae of granular endoplasmic reticulum are occasionally dilated. A distinct feature is the abundance of clear vesicles in the pinealocyte pericapillary terminals, which also frequently contain granular vesicles and a very large vacuole. The pineal is further characterized by the presence of a small number of glial cells and myelinated nerve fibers. A broad perivascular space investing numerous capillaries contains glial-cell and pinealocyte processes, collagen fibrils and abundant unmyelinated nerve fibers. Tortuous extensions of the perivascular space enter the pineal parenchyma where they come in close proximity to branched intercellular channels or canaliculi characterized by specialized junctions and microvilli. Differences between the pineal of the non-hibernating megachiropteran Rousettus and that of the hibernating microchiropteran bats, and structural similarities to the pineal of tropical rodents are discussed. 相似文献
9.
To determine whether Xenopus retinal neurons undergo intrinsic developmental changes in growth properties, retinal explants from embryos and tadpoles of different stages were grown on laminin, fibronectin, and collagen I in serum-free media. Growth was assayed in terms of a neurite growth index (NGI) and the appearance of clockwise bundles, or a clockwise growth index (CGI). The first neurites from stage 25 optic vesicles are pioneers and display a unique growth phenotype; they emerge rapidly, survive for a short time, show little substrate preferences for growth (they grow almost as well on BSA as they do on laminin and fibronectin), and form no clockwise bundles under any conditions. Neurites from progressively older retinas (stages 32-37) share with stage 25 neurites the rapid outgrowth pattern, but begin to show substrate preferences and clockwise growth. From stage 40 to 50, the mature growth pattern is expressed; a lag in initial outgrowth, long-term survival, distinct substrate preferences (they grow 10 times better on laminin and fibronectin than on BSA) and display robust clockwise growth patterns on laminin and fibronectin. The acquisition of clockwise growth is independent of optic fiber contact with the tectum or exposure to diffusible factors from mature brain tissues. The results suggest that retinal neurons undergo developmental modulation of surface adhesive properties and/or cytoskeletal organization. 相似文献
10.
We have previously reported that purified human C-reactive protein (CRP) specifically binds to the cell-binding region of plasma fibronectin (Fn) in a Ca2+-dependent reaction that is saturable at a molar ratio of CRP/Fn of approximately 9. In this study, the binding of CRP to Fn was found to interfere with the cell-attachment promoting activity of Fn. The inhibition of cell attachment was dependent on the concentration of the CRP and involved the phosphorylcholine (PC) binding site of CRP since inhibition was prevented by allowing the CRP to react with either PC (or closely related monophosphate compounds) or a mAb specific for the PC-binding site of CRP. Binding of CRP to laminin was also Ca2+-dependent; however, this binding did not alter the cell-attachment promoting activity of laminin. CRP by itself does not mediate cell attachment. Since CRP is selectively deposited at sites of tissue damage along with plasma Fn and has the ability to bind to Fn and alter its cell-binding activity, CRP may modulate early events in tissue repair. 相似文献