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81.
Multiple trypsin inhibitors from Momordica cochinchinensis seeds, the Chinese drug mubiezhi 总被引:1,自引:0,他引:1
Five trypsin inhibitors, with N-terminal sequences demonstrating homology to each other and exhibiting a molecular weight of 5100, 4800, 4400, 4100, and 3900, respectively, were isolated from Momordica cochinchinensis seeds with a protocol involving acid extraction, ion exchange chromatography on SP-Sepharose chromatography, and RP-HPLC on a C18 column. Specific inhibitory activity against trypsin was demonstrated by the trypsin isoinhibitors with Ki values ranging from 5.3 x 10(-8) to 1.8 x 10(-6) M. None of the isoinhibitors could be cleaved by trypsin. 相似文献
82.
83.
We have previously demonstrated that ET-1 may enhance glucose transport in 3T3-L1 adipocytes, secondarily to its stimulatory effect on GLUT1 gene expression by a mitogen-activated protein kinase (MAPK)-dependent pathway. In the present study, we further tested the involvement of Ca2+ in glucose uptake in response to ET-1. Among a variety of Ca2+-related agents tested, EGTA and thapsigargin were found to suppress both the glucose uptake and intracellular Ca2+ mobilization induced by ET-1, as determined by Fura-2 analysis. However, a phospholipase C inhibitor, U73122, also eliminated the intracellular calcium mobilization induced by ET-1, but had no effect on ET-1-stimulated glucose uptake. The finding that neither EGTA nor thapsigargin had any influence on ET-1-induced MAPK activation implies that some mechanism downstream of MAPK activation is involved. Further investigation showed that both agents exerted global inhibitory effects on protein and RNA syntheses. Since both thapsigargin and EGTA may deplete endoplasmic reticulum (ER) Ca2+ stores, our results suggest that (1) ET-1-induced glucose transport is independent of ET-1's effect on Ca2+ mobilization and (2) depletion of ER Ca2+ stores per se may interfere with ET-1's effect on GLUT1 expression. 相似文献
84.
Increased acute inflammation, leukotriene B4-induced chemotaxis, and signaling in mice deficient for G protein-coupled receptor kinase 6 总被引:1,自引:0,他引:1
Kavelaars A Vroon A Raatgever RP Fong AM Premont RT Patel DD Lefkowitz RJ Heijnen CJ 《Journal of immunology (Baltimore, Md. : 1950)》2003,171(11):6128-6134
Directed migration of polymorphonuclear neutrophils (PMN) is required for adequate host defense against invading organisms and leukotriene B(4) (LTB(4)) is one of the most potent PMN chemoattractants. LTB(4) exerts its action via binding to BLT1, a G protein-coupled receptor. G protein-coupled receptors are phosphorylated by G protein-coupled receptor kinases (GRK) in an agonist-dependent manner, resulting in receptor desensitization. Recently, it has been shown that the human BLT1 is a substrate for GRK6. To investigate the physiological importance of GRK6 for inflammation and LTB(4) signaling in PMN, we used GRK6-deficient mice. The acute inflammatory response (ear swelling and influx of PMN into the ear) after topical application of arachidonic acid was significantly increased in GRK6(-/-) mice. In vitro, GRK6(-/-) PMN showed increased chemokinetic and chemotactic responses to LTB(4). GRK6(-/-) PMN respond to LTB(4) with a prolonged increase in intracellular calcium and prolonged actin polymerization, suggesting impaired LTB(4) receptor desensitization in the absence of GRK6. However, pre-exposure to LTB(4) renders both GRK6(-/-) as well as wild-type PMN refractory to restimulation with LTB(4), indicating that the presence of GRK6 is not required for this process to occur. In conclusion, GRK6 deficiency leads to prolonged BLT1 signaling and increased neutrophil migration. 相似文献
85.
Zager JS Delman KA Malhotra S Ebright MI Bennett JJ Kates T Halterman M Federoff H Fong Y 《Molecular medicine (Cambridge, Mass.)》2001,7(8):561-568
BACKGROUND: Herpes simplex type I (HSV)-based vectors have been used experimentally for suicide gene therapy, immunomodulatory gene delivery, and direct oncolytic therapy. The current study utilizes the novel concept of regional delivery of an oncolytic virus in combination with or serving as the helper virus for packaging herpes-based amplicon vectors carrying a cytokine transgene, with the goal of identifying if this combination is more efficacious than either modality alone. MATERIALS AND METHODS: A replication competent oncolytic HSV (G207) and a replication incompetent HSV amplicon carrying the gene for the immunomodulatory cytokine IL-2 (HSV-IL2) were tested in murine syngeneic colorectal carcinoma and in rat hepatocellular carcinoma models. Liver tumors were treated with vascular delivery of (1) phosphate-buffered saline (PBS), (2) G207, (3) HSV-IL2, (4) G207 and HSV-IL2 mixed in combination (mG207/HSV- IL2), and (5) G207 as the helper virus for packaging the construct HSV-IL2 (pG207/HSV-IL2). RESULTS: Tumor burden was significantly reduced in all treatment groups in both rats and mice treated with high-dose G207, HSV-IL2, or both (p < 0.02). When a low dose of virus was used in mice, anti-tumor efficacy was improved by use of G207 and HSV-IL2 in combination or with HSV-IL2 packaged by G207 (p < 0.001). This improvement was abolished when CD4(+) and CD8(+) lymphocytes were depleted, implying that the enhanced anti-tumor response to low-dose combined therapy is immune mediated. CONCLUSIONS: Vascular regional delivery of oncolytic and amplicon HSV vectors can be used to induce improved anti-tumor efficacy by combining oncolytic and immunostimulatory strategies. 相似文献
86.
We used nigericin, a K+/H+ exchanger, to test whether glucose transport in 3T3-L1 adipocytes was modulated by changes in intracellular pH. Our results showed that nigericin increased basal but decreased insulin-stimulated glucose uptake in a time- and dose-dependent manner. Whereas the basal translocation of GLUT1 was enhanced, insulin-stimulated GLUT4 translocation was inhibited by nigericin. On the other hand, the total amount of neither transporter protein was altered. The finding that insulin-stimulated phosphoinositide 3-kinase (PI 3-kinase) activity was not affected by nigericin implies that nigericin exerted its inhibition at a step downstream of PI 3-kinase activation. At maximal dose, nigericin rapidly lowered cytosolic pH to 6.7; however, this effect was transient and cytosolic pH was back to normal in 20 min. Removal of nigericin from the incubation medium after 20 min abolished its enhancing effect on basal but had little influence on its inhibition of insulin-stimulated glucose transport. Moreover, lowering cytosolic pH to 6.7 with an exogenously added HCl solution had no effect on glucose transport. Taken together, it appears that nigericin may inhibit insulin-stimulated glucose transport mainly by interfering with GLUT4 translocation, probably by a mechanism not related to changes in cytosolic pH. 相似文献
87.
Genetic evidence for the essential role of beta-transducin repeat-containing protein in the inducible processing of NF-kappa B2/p100 总被引:6,自引:0,他引:6
Processing of the nf kappa b2 gene product p100 to generate p52 is an important step in NF-kappa B regulation. This step is regulated by a nonclassical NF-kappa B signaling pathway involving the NF-kappa B-inducing kinase (NIK). NIK induces p100 processing by triggering phosphorylation of specific C-terminal serines of p100. However, the downstream molecular events leading to p100 processing remain unclear. Here we show that NIK induced the physical recruitment of beta-transducin repeat-containing protein (beta-TrCP), a component of the SCF ubiquitin ligase complex, to p100. This event required the phosphorylation sites as well as the death domain of p100. Using the RNA interference technique, we demonstrated that beta-TrCP is essential for NIK-induced p100 ubiquitination and processing. Interestingly the constitutive processing of p100 mutants was independent of beta-TrCP. These results suggest that beta-TrCP is an essential component of NIK-induced p100 processing. 相似文献
88.
Van Hooser JP Liang Y Maeda T Kuksa V Jang GF He YG Rieke F Fong HK Detwiler PB Palczewski K 《The Journal of biological chemistry》2002,277(21):19173-19182
The visual process is initiated by the photoisomerization of 11-cis-retinal to all-trans-retinal. For sustained vision the 11-cis-chromophore must be regenerated from all-trans-retinal. This requires RPE65, a dominant retinal pigment epithelium protein. Disruption of the RPE65 gene results in massive accumulation of all-trans-retinyl esters in the retinal pigment epithelium, lack of 11-cis-retinal and therefore rhodopsin, and ultimately blindness. We reported previously (Van Hooser, J. P., Aleman, T. S., He, Y. G., Cideciyan, A. V., Kuksa, V., Pittler, S. J., Stone, E. M., Jacobson, S. G., and Palczewski, K. (2000) Proc. Natl. Acad. Sci. U. S. A. 97, 8623-8628) that in Rpe65-/- mice, oral administration of 9-cis-retinal generated isorhodopsin, a rod photopigment, and restored light sensitivity to the electroretinogram. Here, we provide evidence that early intervention by 9-cis-retinal administration significantly attenuated retinal ester accumulation and supported rod retinal function for more than 6 months post-treatment. In single cell recordings rod light sensitivity was shown to be a function of the amount of regenerated isorhodopsin; high doses restored rod responses with normal sensitivity and kinetics. Highly attenuated residual rod function was observed in untreated Rpe65-/- mice. This rod function is likely a consequence of low efficiency production of 11-cis-retinal by photo-conversion of all-trans-retinal in the retina as demonstrated by retinoid analysis. These studies show that pharmacological intervention produces long lasting preservation of visual function in dark-reared Rpe65-/- mice and may be a useful therapeutic strategy in recovering vision in humans diagnosed with Leber congenital amaurosis caused by mutations in the RPE65 gene, an inherited group of early onset blinding and retinal degenerations. 相似文献
89.
90.
Increased exopolysaccharide production in Lactococcus lactis due to increased levels of expression of the NIZO B40 eps gene cluster 总被引:3,自引:0,他引:3
Boels IC Van Kranenburg R Kanning MW Chong BF De Vos WM Kleerebezem M 《Applied and environmental microbiology》2003,69(8):5029-5031
Exopolysaccharides (EPS) play an important role in the rheology and texture of fermented food products. This is the first report demonstrating that homologous overexpression of a complete eps gene cluster in Lactococcus lactis leads to increased EPS production levels. A ninefold-elevated EPS plasmid copy number led to an almost threefold increase in the eps expression level, resulting in an almost fourfold increase in the NIZO B40 EPS production level. It was previously reported that increased EPS precursor levels did not influence NIZO B40 EPS production levels. However, the present results indicate that the maximal NIZO B40 EPS production level is limited by the activity level of the expression products of the eps gene cluster rather than by the level of EPS precursors. 相似文献