全文获取类型
收费全文 | 563篇 |
免费 | 37篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 153篇 |
儿科学 | 1篇 |
基础医学 | 66篇 |
口腔科学 | 15篇 |
临床医学 | 18篇 |
内科学 | 28篇 |
神经病学 | 85篇 |
特种医学 | 8篇 |
外科学 | 21篇 |
综合类 | 26篇 |
预防医学 | 18篇 |
眼科学 | 66篇 |
药学 | 73篇 |
中国医学 | 28篇 |
肿瘤学 | 4篇 |
出版年
2023年 | 12篇 |
2022年 | 12篇 |
2021年 | 24篇 |
2020年 | 24篇 |
2019年 | 12篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 18篇 |
2015年 | 13篇 |
2014年 | 23篇 |
2013年 | 101篇 |
2012年 | 24篇 |
2011年 | 32篇 |
2010年 | 17篇 |
2009年 | 33篇 |
2008年 | 28篇 |
2007年 | 22篇 |
2006年 | 21篇 |
2005年 | 19篇 |
2004年 | 16篇 |
2003年 | 15篇 |
2002年 | 7篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 11篇 |
1984年 | 14篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有610条查询结果,搜索用时 31 毫秒
1.
目的:为眼部热力及化学性烧伤导致的睑球粘连寻找一种新的治疗方法。方法:用残留的结膜行1次或多次后退重建结膜囊。结果:1998年以来用此法为38例(40只眼)睑球粘连者进行了治疗,其中13例(13只眼)行2次,19例(21只眼)行3次,仅6例(6只眼)行1次结膜后退成功,其中1例失败。结论:结膜后退法是矫治睑球粘连的一些种有效的方法。 相似文献
2.
Unsharp masking is a widely used image-enhancement method in medical imaging. Hardware-based solutions can be developed to support high computational demand for unsharp masking, but they suffer from limited flexibility. Software solutions can easily incorporate new features and modify key parameters, such as filtering kernel size, but they have not been able to meet the fast computing requirement. Modern programmable mediaprocessors can meet both fast computing and flexibility requirements, which will benefit medical image computing. In this article, we present fast adaptive unsharp masking on two leading mediaprocessors or high-end digital signal processors, Hitachi/Equator Technologies MAP-CA and Texas Instruments TMS320C64x. For a 2k × 2k 16-bit image, our adaptive unsharp masking with a 201 × 201 boxcar kernel takes 225 ms on a 300-MHz MAP-CA and 74 ms on a 600-MHz TMS320C64x. This fast unsharp masking enables technologists and/or physicians to adjust parameters interactively for optimal quality assurance and image viewing. 相似文献
3.
Glezer VD Nevskaya AA Chernova ND Gauzel'man VE 《Neuroscience and behavioral physiology》2005,35(3):319-324
Subjects were trained to discriminate three figures presented in the left field of vision and three other figures presented in the right field of vision. In these conditions, the two hemispheres usually show identical learning to discriminate the sets of stimuli because the hemispheres in healthy humans can exchange information. In the present study, training was performed in conditions in which, during presentation of stimuli, the opposite visual hemifield was covered by a mask. After training, the recognition of all six figures was compared by presenting them to the left and right visual fields. Each hemisphere recognized figures presented to the cognate hemifield but completely or very nearly failed to recognize figures learned by the other hemisphere. The mask would thus appear to block (completely or partially) the transmission of information from one hemisphere to the other. Thus, it was possible to train the hemispheres separately to recognize different sets of images in healthy subjects.Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 89, No. 10, pp. 1177–1183, October, 2003. 相似文献
4.
为掩盖阿奇霉素(azithromycin,AZI)苦味和个性化调控药物释放速度以减少胃肠道刺激,分别以羟丙基纤维素(hydroxypropyl cellulose,HPC)和尤特奇RS100修饰制备速释型AZI-AmberliteTM IRP64/HPC和缓释型AZI-AmberliteTM IRP69/RS100进而组合以实现控制释放。对AZI-离子交换树脂复合物的载药量、药物利用率进行测定,通过差示扫描量热分析和X射线衍射对AZI-离子交换树脂复合物进行结构表征,测定其润湿度、掩味效果、体外溶出和释放行为。结果显示,形成的AZI-离子交换树脂复合物改变了药物原有的结晶状态,2.5%HPC修饰的AZI-AmberliteTM IRP64/HPC和0.5%RS100修饰的AZI-AmberliteTM IRP69/RS100掩味效果良好,两者以对应AZI含量为13∶67的比例组合可以实现AZI在前10 min的快速释放和后期的6 h内平稳释药。结果表明,经表面修饰制得的AZI-离子交换树脂复合物及其... 相似文献
5.
《International journal of audiology》2013,52(5-6):277-282
The main advantages of wearing 2 ear level hearing aids are the possibilities of directional hearing and of avoiding the acoustical head shadow. These effects are rather easy to measure. There exists another effect which would seem, at first sight, to be of major importance: The fact that in an environment of hampering sounds one understands better with 2 ears than with only 1: the cocktail party effect (CPE).As in already described [Kuyper and de Boer, 1969] there are many ways to measure and even to define the CPE. The most natural way (and the best if one investigates hearing aids) is to use loudspeakers. Carhart [1965] describes a method which avoids the effect of head shadow. Unfortunately it was impossible for us to obtain in double prothetized subjects an effect which was greater than the variance.In order to avoid this variance we improved a method developed by Feldmann in 1963, and in this way succeeded in obtaining significant results for each single subject.Applying this method on prothetized subjects, forced us to use the telephone coil instead of the microphone of the post-aural hearing-aids. 相似文献
6.
《Drug testing and analysis》2017,9(1):75-86
In the present work, aqueous normal‐phase liquid chromatography coupled to tandem mass spectrometry (LC‐MS/MS), in different acquisition modes, was employed for the direct analysis and profiling of nine phospholipid classes (phosphatidic acids, phosphatidylserines, phosphatidylethanolamines, lysophosphatidylethanolamines, phosphatidylglycerols, phosphatidylinositols, phosphatidylcholines, lysophosphatidylcholines, and sphingomyelins) in biological and pharmaceutical matrices. After chromatographic separation by a diol column, detection and elucidation of phospholipid and sphingomyelin classes and molecular species were performed by different scan acquisition modes. For screening analysis, molecular ions [M + H]+ were detected in positive precursor ion scan of m /z 184 for the classes of phosphatidylcholines, lyso‐phosphatidylcholines and sphingomyelins; while phosphatidylethanolamines and lyso‐phosphatidylethanolamines were detected monitoring neutral loss scan of 141 Da; and phosphatidylserines detected using neutral loss scan of 184 Da. Molecular ions [M‐H]‐ were instead acquired in negative precursor ion scan of m /z 153 for the classes of phosphatidic acids and phosphatidylglycerols; and of m /z 241 for the phosphatidylinositols. For the identification of the single molecular species, product ion scan mass spectra of the [M + HCOO]‐ ions for phosphatidylcholines and [M + H]+ ions for the other phospholipids considered were determined for each class and compared with the fragmentation pattern of model phospholipid reference standard. By this approach, nearly 100 phospholipids and sphingomyelins were detected and identified. The optimized method was then used to characterize the phospholipid and sphingomyelin profiles in human plasma and urine samples and in two phospholipid‐based pharmaceutical formulations, proving that it also allows to discriminate compounds of endogenous origin from those resulting from the intake of pharmaceutical products containing phospholipidic liposomes. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
7.
《International journal of audiology》2013,52(4):317-323
The authors studied the remote masking (RM) in patients with Menière's disorder during the hearing loss fluctuations produced either by the disorder or by the glycerol test (Klockhoff). The RM was recorded for pulsed tones of 250, 500 and 1 000 Hz; the masker was a continuous narrow-band noise centered at 3 000 Hz, with 305 Hz (2 875–3 180 Hz) bandwidth, delivered at an overall level of 98 dB SPL. The results showed that the RM decreases during the acute phase, i.e. when the hearing loss increases, and, increases if the glycerol tests do not significantly modify the RM value. They seem to confirm the hypothesis that the RM may be due to a mechanical effect in the internal ear and suggest the possibility of using the RM as a test of end-organ rigidity.RésuméLes auteurs ont étudié le RM sur des sujets atteints de maladie de Menière pendant les fluctuations du déficit auditif produites par les crises ou provoquées par le test au glycérol selon Klockhoff. Le RM a été enregistré pour des tons de 250, 500 et 1 000 Hz interrompus deux fois par seconde et d'une durée de 250 ms; le son masquant était un bruit à bande étroite centrée sur la fréquence de 3 000 Hz, d'une largeur de 305 Hz (2 875–3 180 Hz), envoyé en continu à. 98 dB SPL. Les résultats ont montré que la valeur en décibels du RM diminue pendant les crises, lorsque le deficit auditif augmente; au contraire, le RM augmente au moment oú le glycérol produit une amélioration des seuils d'audition. Pour des tests au glycérol négatifs, nous n'avons observé aucune variation marquée du RM. Ces résultats vérifient l'hypothèse de l'origine mécanique du RM et suggèrent la possibilité d'utiliser le RM pour tester la rigidité de la membrane basilaire. 相似文献
8.
《International journal of audiology》2013,52(2):81-91
Upward Spread of Masking in Normal and Impaired EarsUpward spread of masking was studied for normals and sensorineurally hearing-impaired subjects with high-frequency hearing loss. Hearing-impaired listeners were recruited in such a way as to present normal hearing on the frequency of the masker, that is a narrow band of noise centered at 1 000 Hz. Levels of the masker were set at 70, 80 and 90 dB, respectively. Results first indicated the presence of a relationship between masked and elevated absolute thresholds for a masker level of 70 dB. At masker levels of 80 and 90 dB, hearing-impaired listeners showed excessive upward spread of masking in spite of normal hearing sensitivity at the masker frequency: with 80 and 90 dB of noise, upward spread of masking grew, respectively, 2.6 and 1.6 times faster than in normals. Furthermore, excessive upward spread of masking was shown to progress as a function of hearing loss. Results were interpreted as additional evidence of abnormal frequency selectivity in sensorineurally hearing-impaired listeners. 相似文献
9.
《International journal of audiology》2013,52(5-6):271-276
In previous presentations to this congress we have reported an increase in intelligibility of isolated words at poor signal-to-noise ratios when the phase angle differences between the ears were adjusted to certain values. Question has arisen as to whether this phenomenon is one of a peculiar property of speech or one of that kind usually called release from masking. Therefore, a study was done to compare normal voiced speech with whispered speech at a signal-to-noise ratio of 0 dB and subject to various phase angle differences between the ears. Data are presented which suggest that the apparent release from masking may be due in part to properties of voice, but not entirely so. 相似文献
10.
《International journal of audiology》2013,52(2):112-125
A new making transducer is presented which uses a large moving coil driving unit acoustically shielded in a plastic shell. Sound waves are conveyed to the ear by means of a flexible plastic tube and an insert nipple. In tests made under normal clinical situations, it has been found ot provide an interaural isolation from 20-50 dB better than the conventional supra-aural audio-metric earphone and 16-34 dB better than the common hearing-aid type of insert erphone, while being more rugged and more reliable than the latter. It is therefore proposed as a supplementary tool to the clinician, for masking in all cases where other types of transducers are inadequate 相似文献