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971.
972.
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
973.
974.
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
975.
Katynski AL Vijayan MM Kennedy SW Moon TW 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2004,137(1):81-93
Polychlorinated biphenyls (PCB) and other aryl hydrocarbon receptor (AHR) agonists induce oxidative stress and alter membrane lipid peroxidation and fluidity. This study tested the hypothesis that PCB-induced changes in membrane properties impact membrane beta-adrenoceptor (beta-AR) affinity and capacity in chick embryo hepatocytes. Embryos were injected into the air cell with 1.6 microg 3,3',4,4',5-pentachlorobiphenyl (PCB 126)/kg egg at day 0, and incubated to day 19 when livers were removed. This dose resulted in hepatic PCB 126 levels of 0.67 ng/g liver or 10.2 ng/g liver lipid; levels in untreated embryos were non-detectable. Hepatic microsomal EROD activity was elevated by approximately 12-fold and embryo mortality was significantly increased compared with the untreated group. Hepatic lipid peroxidation increased and membrane order (steady-state fluorescence anisotropy values) decreased with in ovo PCB 126 exposure. Consistent with changes in membrane structure, hepatic beta-AR affinity for CGP 12177 significantly decreased (Kd increased) without changes in receptor numbers. This study demonstrates that in ovo exposure to PCB 126 in chick eggs significantly impacted embryo survival, and this was correlated with altered hepatic membrane structure and ultimately membrane function. 相似文献
976.
Kim MJ Jeong LS Kim JH Shin JH Chung SY Lee SK Chun MW 《Nucleosides, nucleotides & nucleic acids》2004,23(4):715-724
In view of biological activities of azole nucleosides and apio-dideoxynucleoside, novel apio nucleoside analogues (1 and 2) with thiazole and triazole base moiety were synthesized using 2,3-O-isopropylidene-apio-beta-D-furanose (3), which was prepared from D-mannose. 相似文献
977.
Hydrophilic interaction liquid chromatography-tandem mass spectrometry for the determination of levosulpiride in human plasma 总被引:4,自引:0,他引:4
Paek IB Moon Y Ji HY Kim HH Lee HW Lee YB Lee HS 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,809(2):345-350
A rapid, sensitive and selective hydrophilic interaction liquid chromatography-tandem mass spectrometric (HILIC-MS/MS) method for the determination of levosulpiride in human plasma was developed. Levosulpiride and internal standard, tiapride were extracted from human plasma with ethyl acetate at pH 11 and analyzed on an Atlantis HILIC silica column with the mobile phase of acetonitrile-ammonium formate (190 mM, pH 3.0) (94:6, v/v). The analytes were detected using an electrospray ionization tandem mass spectrometry in the multiple-reaction-monitoring mode. The standard curve was linear (r = 0.999) over the concentration range of 1.00-200 ng/ml. The lower limit of quantification for levosulpiride was 1.00 ng/ml using 100 microl plasma sample. The coefficient of variation and relative error for intra- and inter-assay at three quality control (QC) levels were 3.8-9.1 and -2.9 to -0.1%, respectively. The recoveries of levosulpiride ranged from 80.5 to 87.4%, with that of tiapride (internal standard) being 84.6%. This method was successfully applied to the pharmacokinetic study of levosulpiride in humans. 相似文献
978.
WNT and beta-catenin signalling: diseases and therapies 总被引:15,自引:0,他引:15
WNT signalling has been studied primarily in developing embryos, in which cells respond to WNTs in a context-dependent manner through changes in survival and proliferation, cell fate and movement. But WNTs also have important functions in adults, and aberrant signalling by WNT pathways is linked to a range of diseases, most notably cancer. What is the full range of diseases that involve WNT pathways? Can inhibition of WNT signalling form the basis of an effective therapy for some cancers? Could activation of WNT signalling provide new therapies for other clinical conditions? Finally, on the basis of recent experiments, might WNTs normally participate in self-renewal, proliferation or differentiation of stem cells? If so, altering WNT signalling might be beneficial to the use of stem cells for therapeutic means. 相似文献
979.
Background
Heptaplatin is a new platinum derivative with anticancer activity against various cancer cell lines, including cisplatin-resistant cancer cell lines (Cancer Chemother Pharmacol 1995; 35: 441). 相似文献980.
Shirai M Yamanishi R Moon JH Murota K Terao J 《Bioscience, biotechnology, and biochemistry》2002,66(5):1015-1021
To clarify the antioxidative role of quercetin metabolites in cellular oxidative stress, we measured the inhibitory effects of the quercetin aglycon and quercetin 3-O-beta-D-glucuronide (Q3GA), which is one of the quercetin metabolites in the blood after an intake of quercetin-rich food, on the production of hydrogen peroxide (H2O2)-induced intracellular reactive oxygen species in mouse fibroblast 3T3 cultured cells. When the cells were exposed to H2O2 in the presence of quercetin or Q3GA, Q3GA was found to be less effective than quercetin. In the case of a pretreatment with quercetin or Q3GA before the exposure, Q3GA, but not the quercetin aglycon, exerted an inhibitory effect, although its cellular uptake was unlikely. The quercetin aglycon appeared to fail in its antioxidative effect due to metabolic conversion into isorhamnetin conjugates, with substantial oxidative degradation resulting from the pretreatment. It is, therefore, suggested that quercetin metabolites take part in the protection of intracellular oxidative stress induced by the extraneous attack of H2O2. 相似文献