全文获取类型
收费全文 | 316篇 |
免费 | 94篇 |
出版年
2021年 | 6篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2016年 | 6篇 |
2015年 | 15篇 |
2014年 | 17篇 |
2013年 | 16篇 |
2012年 | 17篇 |
2011年 | 24篇 |
2010年 | 8篇 |
2009年 | 6篇 |
2008年 | 18篇 |
2007年 | 19篇 |
2006年 | 15篇 |
2005年 | 19篇 |
2004年 | 16篇 |
2003年 | 12篇 |
2002年 | 15篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1994年 | 3篇 |
1992年 | 6篇 |
1991年 | 15篇 |
1990年 | 7篇 |
1989年 | 9篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 8篇 |
1981年 | 3篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1978年 | 6篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1975年 | 6篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1971年 | 4篇 |
1969年 | 4篇 |
1968年 | 2篇 |
1967年 | 3篇 |
排序方式: 共有410条查询结果,搜索用时 140 毫秒
21.
Objective
Although awareness of sleep disorders is increasing, limited information is available on whole night detection of snoring. Our study aimed to develop and validate a robust, high performance, and sensitive whole-night snore detector based on non-contact technology.Design
Sounds during polysomnography (PSG) were recorded using a directional condenser microphone placed 1 m above the bed. An AdaBoost classifier was trained and validated on manually labeled snoring and non-snoring acoustic events.Patients
Sixty-seven subjects (age 52.5±13.5 years, BMI 30.8±4.7 kg/m2, m/f 40/27) referred for PSG for obstructive sleep apnea diagnoses were prospectively and consecutively recruited. Twenty-five subjects were used for the design study; the validation study was blindly performed on the remaining forty-two subjects.Measurements and Results
To train the proposed sound detector, >76,600 acoustic episodes collected in the design study were manually classified by three scorers into snore and non-snore episodes (e.g., bedding noise, coughing, environmental). A feature selection process was applied to select the most discriminative features extracted from time and spectral domains. The average snore/non-snore detection rate (accuracy) for the design group was 98.4% based on a ten-fold cross-validation technique. When tested on the validation group, the average detection rate was 98.2% with sensitivity of 98.0% (snore as a snore) and specificity of 98.3% (noise as noise).Conclusions
Audio-based features extracted from time and spectral domains can accurately discriminate between snore and non-snore acoustic events. This audio analysis approach enables detection and analysis of snoring sounds from a full night in order to produce quantified measures for objective follow-up of patients. 相似文献22.
23.
Synaesthesia is an unusual perceptual experience in which an inducer stimulus triggers a percept in a different domain in addition to its own. To explore the conditions under which synaesthesia evolves, we studied a neuronal network model that represents two recurrently connected neural systems. The interactions in the network evolve according to learning rules that optimize sensory sensitivity. We demonstrate several scenarios, such as sensory deprivation or heightened plasticity, under which synaesthesia can evolve even though the inputs to the two systems are statistically independent and the initial cross-talk interactions are zero. Sensory deprivation is the known causal mechanism for acquired synaesthesia and increased plasticity is implicated in developmental synaesthesia. The model unifies different causes of synaesthesia within a single theoretical framework and repositions synaesthesia not as some quirk of aberrant connectivity, but rather as a functional brain state that can emerge as a consequence of optimising sensory information processing. 相似文献
24.
25.
Yaniv Semel Nicolas Schauer Ute Roessner Dani Zamir Alisdair Robert Fernie 《Metabolomics : Official journal of the Metabolomic Society》2007,3(3):289-295
Every year the consequences of water deficit on crop yield and quality are profound. The observation that many wild species
relatives of cultivated crops display a greater stress tolerance and the fact that the cultivated species generally display
only a fraction of the allelic diversity available within the tomato clade suggest that crossing of wild species with elite
cultivars could improve the stress physiology of modern crops. To assess this from the basis of chemical composition we applied
an established GC-MS based metabolite profiling method to fruits from irrigated and non-irrigated tomato plants either of
the cultivated tomato (Solanum lycopersicum) or of its hybrid with its wild species relative (Solanum pennellii). Results are discussed in terms of both the metabolic response to drought stress and the potential of utilizing exotic germplasm
as a means to improve agronomically important characteristics of crop species.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
26.
In silico screening of a saturated mutation library of tomato 总被引:4,自引:0,他引:4
Menda N Semel Y Peled D Eshed Y Zamir D 《The Plant journal : for cell and molecular biology》2004,38(5):861-872
A comprehensive mutant population is a basic resource for exploring gene function. We developed an isogenic tomato 'mutation library' in the genetic background of the inbred variety M82. A total of 13 000 M(2) families, derived from EMS (ethyl methane sulfonate) and fast-neutron mutagenesis, were visually phenotyped in the field and categorized into a morphological catalog that includes 15 primary and 48 secondary categories. Currently, 3417 mutations have been cataloged; among them are most of the previously described phenotypes from the monogenic mutant collection of The Tomato Genetics Resource Center, and over a thousand new mutants, with multiple alleles per locus. The phenotypic database indicates that most mutations fall into more than a single category (pleiotropic), with some organs such as leaves more prone to alterations than others. All data and images can be searched and accessed in the Solanaceae Genome Network (SGN) on a site called 'The Genes That Make Tomatoes' (http://zamir.sgn.cornell.edu/mutants/). 相似文献
27.
A transcriptional network in polycystic kidney disease 总被引:11,自引:0,他引:11
Gresh L Fischer E Reimann A Tanguy M Garbay S Shao X Hiesberger T Fiette L Igarashi P Yaniv M Pontoglio M 《The EMBO journal》2004,23(7):1657-1668
28.
Constantinescu SN Keren T Russ WP Ubarretxena-Belandia I Malka Y Kubatzky KF Engelman DM Lodish HF Henis YI 《The Journal of biological chemistry》2003,278(44):43755-43763
Erythropoietin receptor (EpoR) activation is crucial for mature red blood cell production. The murine EpoR can also be activated by the envelope protein of the polycythemic (P) spleen focus forming virus (SFFV), gp55-P. Due to differences in the TM sequence, gp55 of the anemic (A) strain SFFV, gp55-A, cannot efficiently activate the EpoR. Using antibody-mediated immunofluorescence co-patching, we show that the majority of EpoR forms hetero-oligomers at the cell surface with gp55-P and, surprisingly, with gp55-A. The EpoR TM domain is targeted by gp55-P and -A, as only chimeric receptors containing EpoR TM sequences oligomerized with gp55 proteins. Both gp55-P and gp55-A are homodimers on the cell surface, as shown by co-patching. However, when the homomeric interactions of the isolated TM domains were assayed by TOXCAT bacterial reporter system, only the TM sequence of gp55-P was dimerized. Thus, homo-oligomerization of gp55 proteins is insufficient for full EpoR activation, and a correct conformation of the dimer in the TM region is required. This is supported by the failure of gp55-A-->P, a mutant protein whose TM domain can homo-oligomerize, to fully activate EpoR. As unliganded EpoR forms TM-dependent but inactive homodimers, we propose that the EpoR can be activated to different extents by homodimeric gp55 proteins, depending on the conformation of the gp55 protein dimer in the TM region. 相似文献
29.
30.
Impaired intervertebral disc formation in the absence of Jun 总被引:11,自引:0,他引:11
Behrens A Haigh J Mechta-Grigoriou F Nagy A Yaniv M Wagner EF 《Development (Cambridge, England)》2003,130(1):103-109