全文获取类型
收费全文 | 483篇 |
免费 | 26篇 |
专业分类
化学 | 417篇 |
晶体学 | 3篇 |
力学 | 6篇 |
数学 | 34篇 |
物理学 | 49篇 |
出版年
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 17篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 20篇 |
2015年 | 14篇 |
2014年 | 11篇 |
2013年 | 19篇 |
2012年 | 36篇 |
2011年 | 29篇 |
2010年 | 20篇 |
2009年 | 27篇 |
2008年 | 41篇 |
2007年 | 40篇 |
2006年 | 33篇 |
2005年 | 34篇 |
2004年 | 23篇 |
2003年 | 29篇 |
2002年 | 31篇 |
2001年 | 10篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 5篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1968年 | 2篇 |
排序方式: 共有509条查询结果,搜索用时 15 毫秒
51.
Carole T. Ferrand 《Journal of voice》1998,12(2):175-181
Forty normally speaking women sustained /a/ five times in two conditions,untimed and timed. In the untimed condition, phonation began whenever the subject felt ready. The timed task required subjects to begin phonation as quickly as possible after the examiner's signal. Conditions were counterbalanced across subjects. Jitter and shimmer values were obtained on a Kay Elemetrics Computerized Speech Lab (Pine Brook, NJ). Three distinct patterns of change emerged for fitter and shimmer from the untimed to the timed condition, reflecting either decreases, increases, or no change in values. These changes in jitter and shimmer values across conditions are related to a reaction time model of “bias toward accuracy.” 相似文献
52.
Arytenoid Cartilage Dislocation: A 20-year Experience 总被引:2,自引:0,他引:2
Adam D. Rubin Mary J. Hawkshaw Cheryl A. Moyer Carole M. Dean Robert T. Sataloff 《Journal of voice》2005,19(4):687-701
SUMMARY: Arytenoid cartilage dislocation is an infrequently diagnosed cause of vocal fold immobility. Seventy-four cases have been reported in the literature to date. Intubation is the most common origin, followed by external laryngeal trauma. Decreased volume and breathiness are the most common presenting symptoms. We report on 63 patients with arytenoid cartilage dislocation treated by the senior author (RTS) since 1983. Significantly more posterior than anterior dislocations were represented. Although reestablishing joint mobility is difficult, endoscopic reduction should be considered to align the heights of the vocal processes. This process may result in significant voice improvement even long after the dislocation. Strobovideolaryngoscopy, laryngeal electromyography, and laryngeal computed tomography (CT) imaging are helpful in the evaluation of patients with vocal fold immobility to help distinguish arytenoid cartilage dislocation from vocal fold paralysis. Familiarity with signs and symptoms of arytenoid cartilage dislocation and current treatment techniques improves the chances for optimal therapeutic results. 相似文献
53.
Javier Ulises Ortiz MayoMartial Thomas Carole SaintoméPascale Clivio 《Tetrahedron》2003,59(37):7377-7383
The synthesis of a building block containing the photobiologically relevant cis-syn thymine cyclobutane photoproduct and its incorporation into oligonucleotides by the phosphoramidite-based solid-phase synthesis is reported. Compared to previous syntheses, this route is extremely short and allows such modified oligonucleotides to be easily available for biological studies. 相似文献
54.
Carole Fraschini Rodica Plesu Jose‐Ramon Sarasua Robert E. Prud'homme 《Journal of Polymer Science.Polymer Physics》2005,43(22):3308-3315
A polylactide of high optical purity was crystallized between 100 and 140 °C, in‐between two glass slides, and its morphology was investigated by polarizing optical microscopy, scanning electron microscopy, and atomic force microscopy, during subsequent heating and cooling cycles between ?15 °C and the crystallization temperature. It was found that dark circular rings show up on cooling on top of the spherulites and represent cracks of about 300 nm in width. This phenomenon is completely reversible, and the heating–cooling curves are centered at about 56 °C, which coincide with the Tg of polylactide. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3308–3315, 2005 相似文献
55.
Carole R. Roth Leslie E. Glaze George S. Goding Jr. William S. David 《Journal of voice》1996,10(4):362-367
A patient initially diagnosed with adductor-type spasmodic dysphonia was referred for botulinum toxin (Botox) injections, but found on subsequent evaluation to have amyotrophic lateral sclerosis, and therefore Botox was not administered. This unique case underscores the need to delay botulinum toxin treatments in any patient with recent onset symptoms, and to obtain thorough motor speech and voice, otolaryngologic, and neurologic evaluation in all patients prior to consideration for injection. 相似文献
56.
Aggregation behaviors of gemini nucleotide at the air-water interface and in solutions induced by adenine-uracil interaction 总被引:2,自引:0,他引:2
Wang Y Desbat B Manet S Aimé C Labrot T Oda R 《Journal of colloid and interface science》2005,283(2):555-564
Cationic gemini surfactants having nucleotides as counterions (called nucleo-gemini hereafter) were synthesized and their aggregation behavior at air-water surfaces as well as in bulk solutions were studied. Fluid solutions of these nucleo-gemini surfactants show transitions to hydrogels upon addition of complementary nucleoside bases or other nucleo-gemini surfactants having complementary bases as counterions. The FTIR-ATR measurements show that the carboxylate groups of uridine form hydrogen bonds with the amine groups of adenosine. The aggregation behavior was also confirmed at the air-water interface by Brewster angle microscopy as well as surface pressure measurements; the monolayer of a gemini nucleotide was observed to undergo a transition to multilayers when nucleosides with complementary bases were added into the subphase. Isotherm curves of surface pressure monitored in parallel show a decrease in molecular area upon addition of such nucleosides. 相似文献
57.
Shirtcliffe NJ McHale G Newton MI Perry CC Roach P 《Chemical communications (Cambridge, England)》2005,(25):3135-3137
Switching between superhydrophobicity and superhydrophilicity in porous materials was predicted theoretically and demonstrated experimentally with the example of thermally induced contact angle change; tunability of this system was also demonstrated. 相似文献
58.
Marquette CA Degiuli A Imbert-Laurenceau E Mallet F Chaix C Mandrand B Blum LJ 《Analytical and bioanalytical chemistry》2005,381(5):1019-1024
Two diagnostic chemiluminescent biochips were developed for either the detection of p53 gene point mutation or the serological detection of anti-HIV-1 p24 capsid protein. Both biochips were composed of 24 microarrays of latex beads spots (4×4) (150 m in diameter, 800 m spacing) entrapped in a poly(dimethylsiloxane) elastomer (PDMS). The latex beads, bearing oligonucleotide sequences or capsid protein, were spotted with a conventional piezoelectric spotter and subsequently transferred at the PDMS interface. The electron microscopy observation of the biochips showed how homogeneous and well distributed the spots could be. Point mutation detection on the codon 273 of the p53 gene was performed on the basis of the melting temperature difference between the perfect match sequence and the one base pair mismatch sequence. The hybridisation of a 20-mer oligonucleotide form the codon 273 including a one base pair mutation in its sequence on a biochip arrayed with non-muted and the muted complementary sequences, enabled a clear discrimination at 56°C between muted and wild sequences. Moreover, the quantitative measurement of the amount of muted sequence in a sample was possible in the range 0.4–4 pmol. Serological measurement of anti-HIV-1 p24 capsid protein on the biochip, prepared with 1-m-diameter latex beads, enabled the detection of monoclonal antibodies in the range 1.55–775 ng mL–1. Such a range could be lowered to 0.775 ng mL–1 when using 50-nm-diameter beads, which generated a higher specific surface. The validation of the biochip for the detection of anti-HIV-1 capsid protein antibodies was performed in human sera from seropositive and seronegative patients. The positivity of the sera was easily discriminated at serum dilutions below 1:1,000. 相似文献
59.
Segmentation under geometrical conditions using geodesic active contours and interpolation using level set methods 总被引:3,自引:0,他引:3
Let I: be a given bounded image function, where is an open and bounded domain which belongs to n. Let us consider n=2 for the purpose of illustration. Also, let S={xi}i be a finite set of given points. We would like to find a contour , such that is an object boundary interpolating the points from S. We combine the ideas of the geodesic active contour (cf. Caselles et al. [7,8]) and of interpolation of points (cf. Zhao et al. [40]) in a level set approach developed by Osher and Sethian [33]. We present modelling of the proposed method, both theoretical results (viscosity solution) and numerical results are given.
AMS subject classification 49L25, 74G65, 68U10 相似文献
60.