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981.
Chun MW Lee HW Kim AY Kim MJ Kim HO Gao ZG Jacobson KA Jeong LS 《Nucleosides, nucleotides & nucleic acids》2005,24(5-7):1119-1121
Novel 3'-ureidoadenosine analogues were synthesized from 1,2:5, 6-di-O-isopropylidene-D-glucose in order to lead to stronger hydrogen bonding at the A3 adenosine receptor than the corresponding 3'-aminoadenosine derivatives. However, all synthesized 3'-ureidoadenosine analogues have lost their binding affinities to the all subtypes of adenosine receptors, indicating that bulky 3'-urea moiety led to conformational distortion. 相似文献
982.
Lee HW Shin DH Jeong JY Kim HO Chun MW Melman N Gao ZG Jacobson KA Jeong LS 《Nucleosides, nucleotides & nucleic acids》2005,24(5-7):607-609
4'-Thionucleoside derivatives as potent and selective A3 adenosaine receptor agonists were synthesized, starting from D-gulono-gamma-lactone via D-thioribosyl acetate as a key intermediate, among which the 2-chloro-N6-methyladenosine-5-methyluronamide showed the most potent and selective binding affinity (Ki = 0.28 +/- 0.09 nM) at the human A3 adenosine receptor. 相似文献
983.
Cell culture on gels made of poly(ethylene oxide) and poly(propylene oxide) (Pluronic), which has a lower critical solution temperature around 30 degrees C, could be performed for 48 h. However, the Pluronic gels were highly hydrophilic and tended to dissolve in the culture medium. We achieved temperature-dependent detachment of cells from Pluronic gels containing or lacking extracellular matrix (ECM) by cooling the gels to 4 degrees C. Using normal human umbilical vein endothelial cells (HUVECs) grown on and released from Pluronic gels lacking ECM, we further found that the expression ratio of the surface markers CD34 and CD105 was twofold higher than for cells grown on polystyrene and removed with trypsin. In addition, the expression ratios for CD34 and CD105 on HUVECs cultivated on the Pluronic gels containing higher concentrations of ECM were lower, which may be due to ECM coating of the cell surface and, thus, interference with antibody binding. In summary, temperature-dependent detachment of cells from Pluronic gels allows the isolation of cells under mild conditions. This can be a powerful tool for surface marker analysis by flow cytometry. 相似文献
984.
985.
986.
Lee JY Kwak JE Moon J Eom SH Liong EC Pedelacq JD Berendzen J Suh SW 《Nature structural biology》2001,8(9):789-794
Homologs of the Escherichia coli surE gene are present in many eubacteria and archaea. Despite the evolutionary conservation, little information is available on the structure and function of their gene products. We have determined the crystal structure of the SurE protein from Thermotoga maritima. The structure reveals the dimeric arrangement of the subunits and an active site around a bound metal ion. We also demonstrate that the SurE protein exhibits a divalent metal ion-dependent phosphatase activity that is inhibited by vanadate or tungstate. In the vanadate- and tungstate-complexed structures, the inhibitors bind adjacent to the divalent metal ion. Our structural and functional analyses identify the SurE proteins as a novel family of metal ion-dependent phosphatases. 相似文献
987.
988.
Mi-Sook?Moon Dong-Hun?Lee Chi-Kyung?KimEmail author 《Biotechnology and Bioprocess Engineering》2004,9(5):393-399
Useful genes can be screened from various environments by construction of metagenomic DNA libraries. In this study, water
samples were collected from several lakes in mid Korea, and analyzed by T-RFLP to examine diversities of the microbial communities.
The crude DNAs were extracted by the SDS-based freezing-thawing method, and then further purified using an UltraCleanTM kit (MoBio, USA). The metagenomic libraries were constructed with the DNAs partially digested withEcoR I,BamH I, andSac II inEscherichia coli DH 10B using the pBACe3.6 vector. About 44.0 Mb of metagenomic libraries were obtained with average inserts 13∼15 kb in size.
ThebphC genes responsible for degradation of aromatic hydrocarbons viameta-cleavage were identified from the metagenomic libraries by colony hybridization using thebphC specific sequence as a probe. The 2,3-dihydroxybiphenyl (2,3-DHBP) dioxygenase gene (bphC), capable of degradation of 2,3-DHBP, was cloned and its nucleotide sequences analyzed. The genes consisted of 966 and 897
base pairs with an ATG initiation codon and a TGA termination codon. The activity of the 2,3-DHBP dioxygenase was highly expressed
to 2,3-DHBP and showed a broad substrate range to 2,3-DHBP, catechol, 3-methylcatechol and 4-methylcatechol. These results
indicated that thebphC gene identified from the metagenomes derived from lake water might be useful in the development of a potent strain for degradation
of aromatic pollutants. 相似文献
989.
990.
Min-Hyuk?Oh Jin-Hong?Kim Yong-Hwan?Moon Choon-Hwan?LeeEmail author 《Journal of Plant Biology》2004,47(4):330-337
During dark-induced leaf senescence (DIS), the non-functional stay-green mutantore10 showed delayed chlorophyll (Chl) degradation and increased stability in its light-harvesting complex II (LHCII). These phenomena
were closely related to the formation of aggregates that mainly consisted of terminal-truncated LHCII (Oh et al., 2003). Theore10 mutant apparently lacks the protease needed to degrade the truncated LHCII. In wild-type (WT) plants, protease was found
in the thylakoid fraction, but not the soluble fraction. A similar experiment using dansylated LHCII revealed that the protease
degraded both WT andore10 LHCII, indicating that its stability inore10 perhaps did not result from a defect in the LHCII polypeptides themselves. Although protease activity was not present in
non-senesced WT leaves, it was induced during DIS. It also was possible to diminish the high level of protease present in
the thylakoids through high-salt washing, suggesting that this enzyme is extrinsically bound to the outer surface of the stroma-exposed
thylakoid regions. 相似文献