全文获取类型
收费全文 | 325篇 |
免费 | 5篇 |
国内免费 | 2篇 |
专业分类
化学 | 95篇 |
晶体学 | 3篇 |
力学 | 1篇 |
数学 | 17篇 |
物理学 | 216篇 |
出版年
2020年 | 5篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2015年 | 4篇 |
2014年 | 7篇 |
2013年 | 11篇 |
2012年 | 8篇 |
2011年 | 16篇 |
2010年 | 5篇 |
2009年 | 4篇 |
2008年 | 4篇 |
2007年 | 7篇 |
2006年 | 10篇 |
2005年 | 14篇 |
2004年 | 10篇 |
2003年 | 11篇 |
2002年 | 14篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 7篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 12篇 |
1995年 | 19篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 13篇 |
1991年 | 10篇 |
1990年 | 20篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 9篇 |
1986年 | 11篇 |
1985年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 6篇 |
1973年 | 4篇 |
1972年 | 2篇 |
1971年 | 5篇 |
1970年 | 2篇 |
1967年 | 2篇 |
排序方式: 共有332条查询结果,搜索用时 15 毫秒
161.
Abrams GS Adolphsen CE Aleksan R Alexander JP Allen MA Atwood WB Averill D Ballam J Bambade P Barish BC Barklow T Barnett BA Bartelt J Bethke S Blockus D de Boer W Bonvicini G Boyarski A Brabson B Breakstone A Breidenbach M Brom JM Brown JL Brown KL Bulos F Burchat PR Burke DL Cence RJ Chapman J Chmeissani M Clendenin J Cords D Coupal DP Dauncey P Dean NR DeStaebler HC Dorfan DE Dorfan JM Drell PS Drewer DC Dydak F Ecklund S Elia R Erickson RA Fay J Feldman GJ Fernandes D Field RC Fieguth TH 《Physical review letters》1989,63(7):724-727
162.
A novel fluorescence assay to monitor in vivo cleavage chemistry of RNA target sequences has been established and used to demonstrate the activity of copper aminoglycoside mediated degradation of RNA in bacterial cells. 相似文献
163.
164.
R. G. Kay C. Barton C. P. Velloso P. R. Brown C. Bartlett A. J. Blazevich R. J. Godfrey G. Goldspink R. Rees G. R. Ball D. A. Cowan S. D. Harridge J. Roberts P. Teale C. S. Creaser 《Rapid communications in mass spectrometry : RCM》2009,23(19):3173-3182
Insulin‐like growth factor‐I (IGF‐I) is a known biomarker of recombinant human growth hormone (rhGH) abuse, and is also used clinically to confirm acromegaly. The protein leucine‐rich α‐2‐glycoprotein (LRG) was recently identified as a putative biomarker of rhGH administration. The combination of an ACN depletion method and a 5‐min ultra‐high‐performance liquid chromatography/tandem mass spectrometry (uHPLC/MS/MS)‐based selected reaction monitoring (SRM) assay detected both IGF‐I and LRG at endogenous concentrations. Four eight‐point standard addition curves of IGF‐I (16–2000 ng/mL) demonstrated good linearity (r2 = 0.9991 and coefficients of variance (CVs) <13%). Serum samples from two rhGH administrations were extracted and their uHPLC/MS/MS‐derived IGF‐I concentrations correlated well against immunochemistry‐derived values. Combining IGF‐I and LRG data improved the separation of treated and placebo states compared with IGF‐I alone, further strengthening the hypothesis that LRG is a biomarker of rhGH administration. Artificial neural networks (ANNs) analysis of the LRG and IGF‐I data demonstrated an improved model over that developed using IGF‐I alone, with a predictive accuracy of 97%, specificity of 96% and sensitivity of 100%. Receiver operator characteristic (ROC) analysis gave an AUC value of 0.98. This study demonstrates the first large scale and high throughput uHPLC/MS/MS‐based quantitation of a medium abundance protein (IGF‐I) in human serum. Furthermore, the data we have presented for the quantitative analysis of IGF‐I suggest that, in this case, monitoring a single SRM transition to a trypsin peptide surrogate is a valid approach to protein quantitation by LC/MS/MS. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
165.
A W Hunt D B Cassidy P A Sterne T E Cowan R H Howell K G Lynn J A Golevchenko 《Physical review letters》2001,86(24):5612-5615
We report the first observation of electron momentum contributions to the Doppler broadening of radiation produced by in-flight two-photon annihilation in solids. In these experiments an approximately 2.5 MeV positron beam impinged on thin polyethylene, aluminum, and gold targets. Since energetic positrons easily penetrate the nuclear Coulomb potential and do not cause a strong charge polarization, the experimental annihilation line shapes agree well with calculations based on a simple independent-particle model. Moreover, annihilations with the deepest core electrons are greatly enhanced. 相似文献
166.
A catalytic metallodrug that targets stem-loop IIb of the internal ribosomal entry site (IRES) RNA of hepatitis C virus (HCV) demonstrates enzyme-like turnover with K(M) of 0.85 μM, k(cat) of 0.53 min(-1), and a turnover number of 31.9 for Cu·GGHYrFK-amide (1-Cu), and yielded an antiviral activity (IC(50)) of 0.58 μM in an HCV cellular replicon assay. 相似文献
167.
Penfold J Staples E Tucker I Carroll P Clayton I Cowan JS Lawton G Amin S Ferrante A Ruddock N 《The journal of physical chemistry. B》2006,110(2):1073-1082
We have used small angle neutron scattering, SANS, to investigate the elongational flow induced ordering in surfactant micelles and mesophases. Spatially resolved SANS measurements have been used to determine the distribution of orientational ordering over the flow velocity pattern in an elongational flow cell, and comparison with the effects of shear flow are made. Two different surfactant systems have been studied, the charged wormlike mixed micelles of hexaethylene monododecyl ether, C16E6/hexadecyl trimethylammonium bromide, C16TAB (3% C16E(6)/5 mol% C16TAB), and the Lalpha lamellar phase of C16E6 (50.6 wt% C16E6 at 55 degrees C), and a substantially different response is observed. The orientational distribution of the Lalpha lamellar phase of C16E6 reflects the flow velocity pattern distribution within the cell, whereas for the wormlike mixed micelles of C16E6/C16TAB this is not the case, and this is associated with the shear thinning behavior of that system. 相似文献
168.
Traynor IM Plumpton L Fodey TL Higgins C Elliott CT 《Journal of AOAC International》2006,89(3):868-872
A rapid and sensitive immuno-based screening method was developed to detect domoic acid (DA) present in extracts of shellfish species using a surface plasmon resonance-based optical biosensor. A rabbit polyclonal antibody raised against DA was mixed with standard or sample extracts and allowed to interact with DA immobilized onto a sensor chip surface. The characterization of the antibody strongly suggested high cross-reactivity with DA and important isomers of the toxin. The binding of this antibody to the sensor chip surface was inhibited in the presence of DA in either standard solutions or sample extracts. The DA chip surface proved to be highly stable, achieving approximately 800 analyses per chip without any loss of surface activity. A single analytical cycle (sample injection, chip regeneration, and system wash) took 10 min to complete. Sample analysis (scallops, mussels, cockles, oysters) was achieved by simple extraction with methanol. These extracts were then filtered and diluted before analysis. Detection limits in the ng/g range were achieved by the assay; however, the assay parameters chosen allowed the test to be performed most accurately at the European Union's official action limit for DA of 20 microg/g. At this concentration, intra- and interassay variations were measured for a range of shellfish species and ranged from 4.5 to 7.4% and 2.3 to 9.7%, respectively. 相似文献
169.
Research supported by NSERC. 相似文献
170.
Nishan Guha David A. Cowan Peter H. Sönksen Richard I. G. Holt 《Analytical and bioanalytical chemistry》2013,405(30):9669-9683
To athletes, insulin-like growth factor-I (IGF-I) is an attractive performance-enhancing drug, particularly as an alternative to growth hormone (GH) because IGF-I mediates many of the anabolic actions of GH. IGF-I has beneficial effects on muscle protein synthesis and glycogen storage that could enhance performance in several sporting disciplines. Recombinant human IGF-I (rhIGF-I) is used in clinical practice, but a variety of IGF-I compounds and IGF-I analogues are also advertised on the internet and many have been available on the black market for several years. Although methods for detecting GH misuse are now well established and there have been several cases in which athletes have tested positive for GH, no test is yet in place for detecting IGF-I misuse. The GH-2004 research group has been investigating methods for detection of IGF-I misuse and a test is being developed on the basis of the principles of the successful GH-2000 marker method, in which markers from the IGF axis and markers of collagen and bone turnover are used to detect GH misuse. Commercial immunoassays for these markers have been validated for anti-doping purposes but new methods, including IGF-I measurement by use of mass spectrometry, should improve the performance of the tests and help in the detection of athletes who are doping with these peptide hormones. Figure
Potential serum markers of IGF-I misuse. rhIGF-I/rhIGFBP-3 administration for 28 days caused an increase in serum IGF-I, P-III-NP and IGFBP-2 and decrease in serum IGF-II and ALS in recreational athletes 相似文献