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41.
Flavonoids from Potentilla parvifolia Fisch. and Their Neuroprotective Effects in Human Neuroblastoma SH‐SY5Y Cells in vitro 下载免费PDF全文
Zhenzhen Yuan Guangxiang Luan Zhenhua Wang Xueyan Hao Ji Li Yourui Suo Gang Li Honglun Wang 《化学与生物多样性》2017,14(6)
Potentilla parvifolia Fisch . (Rosaceae) is a traditional medicinal plant in P. R. China. In this study, seven flavonoids, ayanin ( 1 ), tricin ( 2 ), quercetin ( 3 ), tiliroside ( 4 ), miquelianin ( 5 ), isoquercitrin ( 6 ), and astragalin ( 7 ), were separated and purified from ethyl acetate extractive fractions from ethanol extracts of P. parvifolia using a combination of sevaral chromatographic methods. The human neuroblastoma SH‐SY5Y cells were differentiated with all trans‐retinoic acid and treated with okadaic acid to induce tau protein phosphorylation and synaptic atrophy, which could establish an Alzheimer's disease cell model. The neuroprotective effects of these flavonoids in cellular were evaluated in vitro by this cell model. Results from the Western blot and morphology analysis suggested that compounds 3 and 4 had the better neuroprotective effects. 相似文献
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影响小鼠体细胞脂质体法转染效率的因素 总被引:3,自引:0,他引:3
Jian Ning Yu De Qiang Miao Suo Feng Ma Xiu Wen Tan Ji Hong Yuan Jing He Tan 《实验生物学报》2005,38(5):404-410
We studied the effects of the amount of liposome and plasmid, exposure time of cells to the liposome-plasmid complexes, number of cell passages and cell types on GFP gene transfection of mouse somatic cells. The maximal GFP transgene expression (30.7%) was achieved when mouse fetal fibroblast cells (MFFC) at 70%-90% confluence of passage 3 were exposed for 6 h to the complexes of 4 microg liposome (LipofectAMINE) and 0.3 microg plasmid (pEGFP-N1). Under these conditions, we compared the effect of the number (from primary to 15) of passages on the transfection efficiency of MFFC. The transfection efficiency of MFFC was 10.0%, 28.9% and 7.2% at the primary, 3rd and 15th passage, respectively, which indicated that the transfection efficiency decreased with passaging. When MFFC, mouse oviductal epithelial cells (MOEC) and mouse granulosa cells (MGC) were transfected at passage 3, the transfection efficiency was 27.8%, 13.7% and 14.2%, respectively, under the described transfection conditions. When the cell cycle stages of different cell types at transfection were examined, it was found that 17.2% of MFFC, 8.7% of MOEC and 9.9% of MGC were at M phases of the cell cycle. Examination of the cell cycle stages of MFFC at different passages showed that MFFC at the third passage had the highest percentage of M cells and the percentage decreased afterwards. This suggested that the transfection efficiency was correlated with the percentages of cells at M phase, and provided essential data for improvement of the transfection efficiency. 相似文献
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异三聚体G蛋白在NAA诱导的拟南芥根生长发育中的作用 总被引:2,自引:0,他引:2
以拟南芥的野生型(ws)、异三聚体G蛋白α亚基基因GPA1缺失突变体(gpa1-1,gpa1-2)和超表达突变体(wGα,cGα)为材料,通过施加不同浓度(0~0.2 mg/L)的NAA处理,对拟南芥根生长发育的一些形态指标进行了观测比较.结果表明:(1)随着培养基中NAA浓度的不断升高,5种基因型主根的伸长生长均受到抑制,且抑制作用随浓度升高而增强;4种突变体和野生型主根的生长在相同浓度NAA处理下,无明显差异;(2)NAA在一定浓度范围内,对拟南芥侧根的生长发育起促进作用;在NAA诱导的侧根生长中,G蛋白超表达突变体比野生型更敏感,缺失突变体则不敏感.初步证明G蛋白不参与主根生长发育的调节,而在侧根生长发育中可能起正调节作用. 相似文献
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目的:观察肢体缺血再灌注(LI/R)对胃粘膜的损伤作用及缺血预处理对其影响,探讨胃粘膜损伤的机制及缺血预处理(IPC)的作用机理。方法:观察并测定肢体缺血4h再灌注4h后以及应用肢体缺血预处理干预后各组胃粘膜损伤指数,胃结合粘液量;检测胃粘膜中髓过氧化物酶(MPO)、超氧化物歧化酶(SOD)、丙二醛(MDA)、黄嘌呤氧化酶(XOD)含量的变化以及血浆中乳酸脱氢酶(LDH)的含量变化。结果:大鼠LI/R后胃粘膜损伤指数增加;胃结合粘液量较对照组显著下降;胃粘膜中MPO、MDA、XOD的值均较对照组增加,血浆中LDH的含量亦较对照组显著增加,胃粘膜组织中SOD的酶活力下降;IPC组与LIR组对比,胃结合粘液量较LIR组显著增加:胃粘膜损伤指数、胃粘膜中MPO的含量、以及胃粘膜中MDA、XOD、LDH均较LI/R组明显降低;胃粘膜中SOD酶活力增强。结论:LI/R作为应激原可引起胃粘膜损伤,导致应激性溃疡的发生;自由基在肢体缺血再/灌注后继发胃粘膜损伤过程中发挥作用。缺血预处理可减轻肢体缺血再灌注后的胃粘膜损伤,其作用机制可能是通过减少自由基的产生而发挥其保护作用。 相似文献
47.
During short-patch base excision repair, the excision of a 5'-terminal 2-deoxyribose-5-phosphate moiety of the downstream strand by the 5'-2-deoxyribose-5-phosphate lyase activity of either DNA polymerase beta or lambda is believed to occur after each respective enzyme catalyzes gap-filling DNA synthesis. Yet the effects of this 5'-terminal 2-deoxyribose-5-phosphate moiety on the polymerase activities of these two enzymes have never been quantitatively determined. Moreover, x-ray crystal structures of truncated polymerase lambda have revealed that the downstream strand and its 5'-phosphate group of gapped DNA interact intensely with the dRPase domain, but the kinetic effect of these interactions is unclear. Here, we utilized pre-steady state kinetic methods to systematically investigate the effect of a downstream strand and its 5'-moieties on the polymerase activity of the full-length human polymerase lambda. The downstream strand and its 5'-phosphate were both found to increase nucleotide incorporation efficiency (kp/Kd) by 15 and 11-fold, respectively, with the increase procured by the effect on the nucleotide incorporation rate constant kp rather than the ground state nucleotide binding affinity Kd. With 4 single nucleotide-gapped DNA substrates containing a 1,2-dideoxyribose-5-phosphate moiety, a 2-deoxyribose-5-phosphate mimic, we measured the incorporation efficiencies of 16 possible nucleotides. Our results demonstrate that although this 5'-terminal 2-deoxyribose-5-phosphate mimic does not affect the fidelity of polymerase lambda, it moderately decreased the polymerase efficiency by 3.4-fold. Moreover, this decrease in polymerase efficiency is due to a drop of similar magnitude in kp rather than Kd. The implication of the downstream strand and its 5'-moieties on the kinetics of gap-filling synthesis is discussed. 相似文献
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Jun-Xue Jin Suo LiYu Hong Long JinHai-Ying Zhu Qing GuoQing-Shan Gao Chang-Guo YanJin-Dan Kang Xi-Jun Yin 《Theriogenology》2014
The aim of the present study was to examine the effects of CUDC-101, a novel histone deacetylase inhibitor, on the in vitro development and expression of the epigenetic marker histone H3 at lysine 9 (AcH3K9) in pig SCNT embryos. We found that treatment with 1 μmol/L CUDC-101 for 24 hours significantly improved the development of pig SCNT embryos. Compared with the control group, the blastocyst rate was higher (18.5% vs. 10.3%; P < 0.05). To assess in vivo developmental potency, CUDC-101–treated SCNT embryos were transferred into two surrogate mothers, resulting in one pregnancy with six fetuses. We then investigated the acetylation level of histone H3K9 in SCNT embryos treated with CUDC-101 and compared them only against untreated embryos. The acetylation level of control SCNT embryos was lower than that of CUDC-101–treated embryos at pseudo-pronuclear stages, and immunofluorescent signal for H3K9ac in CUDC-101–treated embryos in a pattern similar to that of control group. In conclusion, we demonstrated that CUDC-101 can significantly improve in vitro and in vivo developmental competence and enhance the nuclear reprogramming of pig SCNT embryos. 相似文献
49.
The WNK (With No Lysine K) serine-threonine kinases have been shown to be osmosensitive regulators and are critical for cell volume homeostasis in humans. We previously identified a soybean root-specific WNK homolog, GmWNK1, which is important for normal late root development by fine-tuning regulation of ABA levels. However, the functions of WNKs in plant osmotic stress response remains uncertain. In this study, we generated transgenic Arabidopsis plants with constitutive expression of GmWNK1. We found that these transgenic plants had increased endogenous ABA levels and altered expression of ABA-responsive genes, and exhibited a significantly enhanced tolerance to NaCl and osmotic stresses during seed germination and seedling development. These findings suggest that, in addition to regulating root development, GmWNK1 also regulates ABA-responsive gene expression and/or interacts with other stress related signals, thereby modulating osmotic stress responses. Thus, these results suggest that WNKs are members of an evolutionarily conserved kinase family that modulates cellular response to osmotic stresses in both animal and plants. 相似文献
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AimsThe aim of this study was to investigate the mechanism for the reversal effect of NF449 (a suramin analogue) on the neuromuscular block induced by d-tubocurarine (d-TC).Main methodsNerve-stimulated muscle contractions and end-plate potentials were performed in mouse phrenic nerve-diaphragm preparations. Acetylcholine (ACh)-induced muscle contractions were performed in the chick biventer cervicis preparations. Presynaptic nerve terminal waveform recordings were performed in mouse triangularis sterni preparations.Key findingsAmongst the suramin analogues in this study, only the NF449 and suramin were able to reverse the blockade effect produced by d-TC on nerve-stimulated muscle contractions. Each of these suramin analogues (NF007, NF023, NF279 and NF449) alone has no significant effect on the amplitude of nerve-stimulated muscle contractions. NF449 and suramin also showed the antagonising effects on the inhibition of end-plate potentials induced by d-TC. Furthermore, pre-treatment with NF449 can antagonise the inhibition of d-TC in ACh-induced contractions of chick biventer cervicis muscle. NF449 produced a greater rightward shift of the dose–response inhibition curve for d-TC than did suramin. Because other purinergic 2X (P2X) receptor antagonists, NF023 and NF279, do not have the reverse effects on the neuromuscular blockade of d-TC, the effect of NF449 seems irrelevant to inhibition of P2X receptors.SignificanceThese data suggest that NF449 was able to compete with the binding of d-TC on the nicotinic ACh receptors, and the effect of NF449 was more potent than suramin in reducing the inhibition of d-TC. The structure of NF449 may provide useful information for designing potent antidotes against neuromuscular toxins. 相似文献