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排序方式: 共有719条查询结果,搜索用时 15 毫秒
41.
Daniel J. Peart Richard J. Kirk Leigh A. Madden Jason C. Siegler Rebecca V. Vince 《Amino acids》2013,44(3):903-910
The aim of this study was to observe the intracellular heat shock protein 72 (HSP72) and heme oxygenase-1 (HSP32) response to prolonged interval cycling following the ingestion of carbohydrates (CHO) and sodium bicarbonate (NaHCO3). Six recreationally active males (mean ± SD; age 23.2 ± 2.9 years, height 179.5 ± 5.5 cm, body mass 76.5 ± 6.8 kg, and peak power output 315 ± 36 W) volunteered to complete a 90 min interval cycling exercise on four occasions. The trials were completed in a random and blinded manner following ingestion of either: placebo and an artificial sweetener (P–P), NaHCO3 and sweetener (B–P), placebo and CHO (P–CHO), and NaHCO3 and CHO (B–CHO). Both HSP72 and HSP32 were significantly increased in monocytes and lymphocytes from 45 min post-exercise (p ≤ 0.039), with strong relationships between both cell types (HSP72, r = 0.83; HSP32, r = 0.89). Exogenous CHO had no influence on either HSP72 or HSP32, but the ingestion of NaHCO3 significantly attenuated HSP32 in monocytes and lymphocytes (p ≤ 0.042). In conclusion, the intracellular stress protein response to 90 min interval exercise is closely related in monocytes and lymphocytes, and HSP32 appears to be attenuated with a pre-exercise alkalosis. 相似文献
42.
Ernest K. Amankwah Reid C. Thompson L. Burton Nabors Jeffrey J. Olson James E. Browning Melissa H. Madden Kathleen M. Egan 《Cancer epidemiology》2013,37(2):162-165
Background: The human SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complex plays essential roles in a variety of cellular processes and has been implicated in human cancer. However, the role of germline genetic variants in this complex in relation to cancer risk is not well studied. Methods: We assessed the association of 16 variants in the catalytic subunits (SMARCA2 and SMARCA4) of the SWI/SNF complex with the risk of glioma subtypes (lower grade astrocytoma, oligodendroglioma and glioblastoma [GBM]) and with mortality from high-grade tumors (GBM) in a multicenter US case–control study that included 561 cases and 574 controls. Associations were estimated with odds ratios (OR, for risk) or hazards ratios (HR, for mortality) with 95% confidence intervals (CI). False discovery rate (FDR-q) was used to control for multiple testing in risk associations. Results: None of the investigated SNPs was associated with overall glioma risk. However, analyses according to histological subtypes revealed a statistically significant increased risk of oligodendroglioma in association with SMARCA2 rs2296212 (OR = 4.05, 95%CI = 1.11–14.80, P = 0.030, q = 0.08) and rs4741651 (OR = 4.68, 95%CI = 1.43–15.30, P = 0.011, q = 0.08) and SMARCA4 rs11672232 (OR = 1.90, 95%CI = 1.01–3.58, P = 0.048, q = 0.08) and rs12232780 (OR = 2.14, 95%CI = 1.06–4.33, P = 0.035, q = 0.08). No significant risk associations were observed for GBM or lower grade astrocytoma. Suggestive associations with GBM mortality were not validated in the Cancer Genome Atlas. Conclusion: Our findings suggest that genetic variants in SMARCA2 and SMARCA4 influence the risk of oligodendroglioma. Further research is warranted on the SWI/SNF complex genes and epigenetic mechanisms more generally in the development of glioma in adults. 相似文献
43.
Programmed cell death (PCD) plays critical roles during development and in disease states. One form of programmed cell death utilizes autophagy--a cellular mechanism of degrading bulk cytosolic components--to destroy cells. Previously, the broad-spectrum caspase inhibitor z-Val-Ala-Asp(OMe)-fluoromethylketone (zVAD) was shown to induce autophagic cell death. The mechanism of Zvad-induced cell death was proposed to require caspase-8 inhibition. In our report, we extend these findings to show that--as is the case for apoptosis--induction of autophagic cell death in response to zVAD results in phosphatidylserine exposure prior to loss of membrane integrity. Additionally, we show that caspase-8 inhibition is insufficient to cause autophagic cell death. Rather, the activity of a calpain-like protease must also be blocked. These results reveal the existence of an autophagic PCD-inhibiting calpain-like cysteine protease. 相似文献
44.
A Proteomics Approach to Characterizing Tick Salivary Secretions 总被引:1,自引:0,他引:1
The saliva of ticks contains a complex mixture of bioactive molecules including proteins that modulate host responses ensuring successful feeding. The limited amount of saliva that can be obtained from ticks has hampered characterization of salivary proteins using traditional protein chemistry. Recent improvements in two-dimensional gel electrophoresis, mass spectrometry, and bioinformatics provide new tools to characterize small amounts of protein. These methods were employed to characterize salivary proteins from Amblyomma americanum and Amblyvomma maculatum. Salivation was induced by injection of dopamine and theophylline. It was necessary to desalt and concentrate saliva before analysis by 2-D electrophoresis. Comparison of 1-D and 2-D gel patterns revealed that the major protein component of saliva did not appear on 2-D gels. Characterization of this protein showed that it was identical to the major protein present in the hemolymph of both tick species. Protein profiles obtained by 1-D and 2-D gel electrophoresis were similar for both tick species, however, higher concentrations of lower molecular weight proteins were present in A. maculatum. Protein analysis by MALDI-TOF mass spectrometry and western blot analysis showed that except for the most abundant protein with a molecular weight of 95 kDa, all of the proteins detected were of host origin. It is not known if this is an artifact of the collection method or has physiological significance. In either case, in these species of ticks, host proteins will have to be removed from saliva samples prior to 2-D analysis in order to characterize lower abundance proteins of tick origin. 相似文献
45.
Structural and kinetic characterization of myoglobins from eurythermal and stenothermal fish species
Madden PW Babcock MJ Vayda ME Cashon RE 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2004,137(3):341-350
Teleost myoglobin (Mb) proteins from four fish species inhabiting different temperature environments were used to investigate the relationship between protein function and thermal stability. Mb was isolated from yellowfin tuna (homeothermal warm), mackerel (eurythermal warm), and the Antarctic teleost Notothenia coriiceps (stenothermal cold). Zebrafish (stenothermal tropical) myoglobin was expressed from cloned cDNA. These proteins differed in oxygen affinity, as measured by O2 dissociation rates and P50 values, and thermal stability as measured by autooxidation rates. Mackerel Mb had the highest P50 value at 25 degrees C (3.7 mmHg), corresponding to the lowest O2 affinity, followed by zebrafish (1.0 mmHg), yellowfin tuna (1.0 mmHg), and N. coriiceps (0.6 mmHg). Oxygen dissociation rates and Arrhenius plots were similar between all teleost species in this study, with the exception of mackerel myoglobin, which was two-fold faster at all temperatures tested. Myoglobin from the Antarctic teleost had the highest autooxidation rate (0.44 h(-1)), followed by mackerel (0.26 h(-1)), zebrafish (0.22 h(-1)), and yellowfin tuna (0.088 h(-1)). Primary structural analysis revealed residue differences distributed throughout the polypeptide sequences, making it difficult to identify, which, if any, residues contribute to structural flexibility. However, analysis of molecular dynamics trajectories indicates that Mb from the eurythermal mackerel is predicted to be the most flexible protein within the D loop and FG turn. At the same time, it has the lowest O2 affinity and the highest O2 dissociation rates when compared to myoglobins from teleosts that appear to be less flexible in our dynamics simulations. 相似文献
46.
Vander Heyden MA Halla TR Madden JA Gordon JB 《American journal of physiology. Lung cellular and molecular physiology》2001,280(3):L519-L526
We previously found that alkalosis-induced vasodilation was mediated by endothelium-derived nitric oxide (EDNO) in newborn piglet pulmonary artery and vein rings precontracted with the thromboxane mimetic U-46619. In contrast, prostacyclin or K(+) channel activation contributed to the response in other preparations. This study was undertaken to determine whether EDNO alone also mediates alkalosis-induced pulmonary vasodilation in piglet lungs vasoconstricted with hypoxia and, if not, to identify the mediator(s) involved. Responses to alkalosis were measured during hypoxia under control conditions after blocking nitric oxide synthase (N(omega)-nitro-L-arginine), cyclooxygenase (meclofenamate), or both endothelium-derived modulators (Dual); after blocking voltage-dependent (4-aminopyridine), ATP- dependent (glibenclamide), or Ca(2+)-dependent K(+) (K(Ca); tetraethylammonium) K(+) channels; and after blocking both endothelium-derived modulators and K(Ca) channels (Triple). Vasodilator responses measured after 20 min of alkalosis were blunted in Dual and tetraethylammonium lungs and abolished in Triple lungs. Thus alkalosis-induced vasodilation in hypoxic lungs appeared to be mediated by three Ca(2+)-dependent modulators: EDNO, prostacyclin, and K(Ca) channels. In addition, a transient, unidentified modulator contributed to the nadir of the vasodilator response measured at 10 min of alkalosis. Future studies are needed to identify factors that contribute to the discordance between isolated vessels and whole lungs. 相似文献
47.
Madden M Salo WL Streitz J Aufderheide AC Fornaciari G Jaramillo C Vallejo GA Yockteng R Arriaza B Cárdenas-Arroyo F Guhl F 《BioTechniques》2001,30(1):102-4, 106, 108-9
Single strands of very short PCR products can be covalently immobilized to a slide and then easily detected by probe hybridization. In this work, the PCR product was a 70-nucleotide segment of ancient DNA, representing a portion of repeat mini-circle DNA from the kinetoplast of Trypanosoma cruzi, the infectious agent of Chagas' disease (American Trypanosomiasis). The target segment was initially established to be present in soft tissue samples taken from four "naturally" mummified Andean bodies using PCR followed by cloning and sequencing. Hybridization screening of the covalently immobilized PCR products positively identified products from 25 of 27 specimens of different tissues from these four mummies. The method appears to be ideal for the purpose of screening a large number of specimens when the target PCR product is very short. 相似文献
48.
De La Vega FM Dailey D Ziegle J Williams J Madden D Gilbert DA 《BioTechniques》2002,(Z1):48-50, 52, 54
Since public and private efforts announced the first draft of the human genome last year, researchers have reported great numbers of single nucleotide polymorphisms (SNPs). We believe that the availability of well-mapped, quality SNP markers constitutes the gateway to a revolution in genetics and personalized medicine that will lead to better diagnosis and treatment of common complex disorders. A new generation of tools and public SNP resources for pharmacogenomic and genetic studies--specifically for candidate-gene, candidate-region, and whole-genome association studies--will form part of the new scientific landscape. This will only be possible through the greater accessibility of SNP resources and superior high-throughput instrumentation-assay systems that enable affordable, highly productive large-scale genetic studies. We are contributing to this effort by developing a high-quality linkage disequilibrium SNP marker map and an accompanying set of ready-to-use, validated SNP assays across every gene in the human genome. This effort incorporates both the public sequence and SNP data sources, and Celera Genomics' human genome assembly and enormous resource ofphysically mapped SNPs (approximately 4,000,000 unique records). This article discusses our approach and methodology for designing the map, choosing quality SNPs, designing and validating these assays, and obtaining population frequency ofthe polymorphisms. We also discuss an advanced, high-performance SNP assay chemisty--a new generation of the TaqMan probe-based, 5' nuclease assay-and high-throughput instrumentation-software system for large-scale genotyping. We provide the new SNP map and validation information, validated SNP assays and reagents, and instrumentation systems as a novel resource for genetic discoveries. 相似文献
49.
Altered DNA mutation spectrum in aflatoxin b1-treated transgenic mice that express the hepatitis B virus x protein 总被引:8,自引:0,他引:8
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Humans chronically infected with hepatitis B virus (HBV) are at further risk of liver cancer upon exposure to dietary aflatoxin B1 (AFB1), a carcinogenic product of the mold Aspergillus flavus. For the present study, we utilized double-transgenic mice (ATX mice) that express the HBV X protein (HBx) and possess a bacteriophage lambda transgene to evaluate the in vivo effect of HBx expression on AFB1-induced DNA mutations. The expression of HBx correlated with a 24% increase in mutation frequency overall and an approximately twofold increase in the incidence of G/C-to-T/A transversion mutations following AFB1 exposure. These results are consistent with a model in which expression of HBx during chronic HBV infection may contribute to the development of hepatocellular carcinoma following exposure to environmental carcinogens. 相似文献
50.