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排序方式: 共有360条查询结果,搜索用时 31 毫秒
41.
Luciano F Zhai D Zhu X Bailly-Maitre B Ricci JE Satterthwait AC Reed JC 《The Journal of biological chemistry》2005,280(16):15825-15835
Humanin (HN) is a recently identified endogenous peptide that protects cells against cytotoxicity induced by various stimuli. Recently, we showed that HN binds to and inhibits Bax, a proapoptotic Bcl-2 family protein, suggesting a mechanism for HN action. In this study, we identified Bim, a Bcl-2 homology 3-only member of the Bcl-2/Bax family, as an additional HN target protein. Using in vitro protein binding, immunoprecipitation, and coimmunolocalization assays, we demonstrated that HN binds directly to the extra long isoform of Bim (BimEL) but not the long (BimL) or short (BimS) isoforms. HN also protects cells against apoptosis induced by BimEL but not BimL and BimS in gene transfection studies. In contrast, mutants of HN which failed to bind BimEL failed to protect from BimEL-induced cell death. Moreover, HN inhibited BimEL-induced release of SMAC and cytochrome c from mitochondria isolated from bax-/-cells, indicating that HN can suppress BimEL independently of its effect on Bax. Finally, we demonstrate that HN prevents BimEL-induced oligomerization of Bak using isolated mitochondria. Taken together, our results indicate that the inhibition of BimEL may contribute to the antiapoptotic properties of the HN peptide. 相似文献
42.
Yang W Lu Y Kalajzic I Guo D Harris MA Gluhak-Heinrich J Kotha S Bonewald LF Feng JQ Rowe DW Turner CH Robling AG Harris SE 《The Journal of biological chemistry》2005,280(21):20680-20690
43.
Dayong Zhai Eric Yu Chaofang Jin Kate Welsh Chung-wei Shiau Lili Chen Guy S. Salvesen Robert Liddington John C. Reed 《The Journal of biological chemistry》2010,285(8):5569-5580
Apoptosis plays important roles in host defense, including the elimination of virus-infected cells. The executioners of apoptosis are caspase family proteases. We report that vaccinia virus-encoded F1L protein, previously recognized as anti-apoptotic viral Bcl-2 family protein, is a caspase-9 inhibitor. F1L binds to and specifically inhibits caspase-9, the apical protease in the mitochondrial cell death pathway while failing to inhibit other caspases. In cells, F1L inhibits apoptosis and proteolytic processing of caspases induced by overexpression of caspase-9 but not caspase-8. An N-terminal region of F1L preceding the Bcl-2-like fold accounts for caspase-9 inhibition and significantly contributes to the anti-apoptotic activity of F1L. Viral F1L thus provides the first example of caspase inhibition by a Bcl-2 family member; it functions both as a suppressor of proapoptotic Bcl-2 family proteins and as an inhibitor of caspase-9, thereby neutralizing two sequential steps in the mitochondrial cell death pathway. 相似文献
44.
An electromagnetic (EM) heating system is developed to achieve the rapid and uniform warming of cryopreserved biomaterials. Using the heating system, a rectangular resonant cavity is excited in TE101 mode at frequencies near 434 MHz. In experiments, a spherical phantom of biomaterial with a diameter of 36 mm is placed at the center of the cavity. The phantom is first cooled down to about -80 degrees C within the cavity and then thawed by EM absorption. Results show that EM warming can produce much higher warming rate than conventional water-bath warming method. The spatial temperature distribution in the phantom during EM warming is also more uniform than that during the water-bath warming. 相似文献
45.
Recent diabetes and obesity research has been focused on the role of intracellular lipids in insulin resistance. Fatty acyl-coenzyme A (CoA) esters play a central role in the trafficking of intracellular lipids, but there has not previously been a method with which to quantify their kinetics using tracer methodology. We have therefore developed a high-performance liquid chromatography (HPLC)-mass spectrometry method to simultaneously measure the (13)C stable isotopic enrichment of palmitoyl-acyl-CoA ester and the concentrations of five individual long-chain fatty acyl-CoA esters extracted from muscle tissue samples. The long-chain fatty acyl-CoA can be effectively extracted from frozen muscle tissue samples and baseline separated by a reverse-phase HPLC with the presence of a volatile reagent-triethylamine. Negative ion electrospray mass spectrometry with selected ion monitoring was used to analyze the fatty acyl-CoAs to achieve reliable quantification of their concentrations and (13)C isotopic enrichment. Applying this protocol to rabbit muscle samples demonstrates that it is a sensitive, accurate, and precise method for the quantification of long-chain fatty acyl-CoA concentrations and enrichment. 相似文献
46.
Si D Urano N Nozaki S Honda K Shimizu S Kataoka M 《Applied microbiology and biotechnology》2012,95(2):431-440
The 1,2-propanediol (1,2-PD) inducible membrane-bound L-pantoyl lactone (L-PL) dehydrogenase (LPLDH) has been isolated from Rhodococcus erythropolis AKU2103 (Kataoka et al. in Eur J Biochem 204:799, 1992). Based on the N-terminal amino acid sequence of LPLDH and the highly conserved amino acid sequence in homology search results, the LPLDH gene (lpldh) was cloned. The gene consists of 1,179 bases and encodes a protein of 392 amino acid residues. The deduced amino acid sequence showed high similarity to the proteins of the FMN-dependent α-hydroxy acid dehydrogenase/oxidase family. The overexpression vector pKLPLDH containing lpldh with its upstream region (1,940 bp) was constructed and introduced into R. erythropolis AKU2103. The recombinant R. erythropolis AKU2103 harboring pKLPLDH showed six times higher LPLDH activity than the wild-type strain. Conversion of L-PL to ketopantoyl lactone was achieved with 92% or 80% conversion yield when the substrate concentration was 0.768 or 1.15 M, respectively. Stereoinversion of L-PL to D-PL was also carried out by using the combination of recombinant R. erythropolis AKU2103 harboring pKLPLDH and ketopantoic acid-reducing Escherichia coli. 相似文献
47.
T Xin F Zhang Q Jiang C Chen D Huang Y Li W Shen Y Jin G Sui 《International journal of biological macromolecules》2012,51(5):788-793
In this study, we prepared an acidic polysaccharide (CPPA) from the roots of Codonopsis pilosula. The effects of CPPA on tumor cell growth, invasion, and migration were examined in vitro. The CPPA not only induced a potent inhibitory effect on the invasion and migration potential of human epithelial ovarian cancer HO-8910 cells in vitro, evaluated by wound healing, transwell and cell adhesion assays, but also had an efficient anti-proliferation effect on tumor cells. Moreover, the CD44 expression on the HO-8910 cells was also attenuated by CPPA treatment. Therefore, our results indicate that CPPA may be a potential candidate compound for the prevention of tumor metastasis, presumably by inhibiting invasion, migration and adhesion of tumor cells, as well as the CD44 expression on the tumor cells. 相似文献
48.
Two acidic polysaccharide fractions (PTPa and PTPb) extracted from the roots of Polygala tenuifolia, were obtained by DEAE-Sephacel anion-exchange, and Sephadex G-100 gel-permeation chromatography. High-performance liquid chromatography (HPLC) identified that PTPa and PTPb was composed of Ara, Glc, Gal, Man and GlcUA in the proportion of 2.4:1.2:0.6:0.4:1.1 and 2.1:1.7:0.5:0.6:1.7, respectively. Their molecular weight was evaluated to be 5.9×10(4) (PTPa) and 2.5×10(4)Da (PTPb) as determined by high performance size exclusion chromatography (HPSEC). Pharmacological studies revealed PTPa and PTPb significantly inhibited the growth of A549 cells in vitro and exhibited significantly higher antitumor activity against solid tumor A549 in vivo than did a blank control. Moreover, treatment with two acidic polysaccharides caused an enhancement of superoxide dismutase (SOD) and catalase (CAT) activities in tumor-bearing mice and a reduction in thiobarbituric acid reactive substances (TBARS) level. Taken together, these results indicated that two acidic polysaccharides from the roots of P. tenuifolia may be useful as potent antitumor agents for the prevention of lung tumorigenesis. 相似文献
49.
Allografts of the acellular sciatic nerve and brain-derived neurotrophic factor repair spinal cord injury in adult rats 总被引:1,自引:0,他引:1
Objective
We aimed to investigate whether an innovative growth factor-laden scaffold composed of acellular sciatic nerve (ASN) and brain-derived neurotrophic factor (BDNF) could promote axonal regeneration and functional recovery after spinal cord injury (SCI).Methods
Following complete transection at the thoracic level (T9), we immediately transplanted the grafts between the stumps of the severed spinal cords. We evaluated the functional recovery of the hindlimbs of the operated rats using the BBB locomotor rating scale system every week. Eight weeks after surgery, axonal regeneration was examined using the fluorogold (FG) retrograde tracing method. Electrophysiological analysis was carried out to evaluate the improvement in the neuronal circuits. Immunohistochemistry was employed to identify local injuries and recovery.Results
The results of the Basso-Beattie-Bresnahan (BBB) scale indicated that there was no significant difference between the individual groups. The FG retrograde tracing and electrophysiological analyses indicated that the transplantation of ASN-BDNF provided a permissive environment to support neuron regeneration.Conclusion
The ASN-BDNF transplantation provided a promising therapeutic approach to promote axonal regeneration and recovery after SCI, and can be used as part of a combinatory treatment strategy for SCI management. 相似文献50.
Alberto Molano Zhaofeng Huang Melissa G. Marko Angelo Azzi Dayong Wu Elaine Wang Samuel L. Kelly Alfred H. Merrill Jr Stephen C. Bunnell Simin Nikbin Meydani 《PloS one》2012,7(10)
To determine whether changes in sphingolipid composition are associated with age-related immune dysfunction, we analyzed the core sphingolipidome (i.e., all of the metabolites through the first headgroup additions) of young and aged CD4+ T cells. Since sphingolipids influence the biophysical properties of membranes, we evaluated the compositions of immune synapse (IS) and non-IS fractions prepared by magnetic immuno-isolation. Broadly, increased amounts of sphingomyelins, dihydrosphingomyelins and ceramides were found in aged CD4+ T cells. After normalizing for total sphingolipid content, a statistically significant decrease in the molar fraction of glucosylceramides was evident in both the non-IS and IS fractions of aged T cells. This change was balanced by less dramatic increases in the molar fractions of sphingomyelins and dihydrosphingomyelins in aged CD4+ T cells. In vitro, the direct or enzymatic enhancement of ceramide levels decreased CD4+ T cell proliferation without regard for the age of the responding T cells. In contrast, the in vitro inhibition of glucosylceramidase preferentially increased the proliferation of aged CD4+ T cells. These results suggest that reductions in glucosylceramide abundance contribute to age-related impairments in CD4+ T cell function. 相似文献