全文获取类型
收费全文 | 8170篇 |
免费 | 706篇 |
国内免费 | 206篇 |
专业分类
耳鼻咽喉 | 60篇 |
儿科学 | 133篇 |
妇产科学 | 104篇 |
基础医学 | 1366篇 |
口腔科学 | 258篇 |
临床医学 | 546篇 |
内科学 | 872篇 |
皮肤病学 | 209篇 |
神经病学 | 959篇 |
特种医学 | 177篇 |
外科学 | 425篇 |
综合类 | 1039篇 |
现状与发展 | 1篇 |
预防医学 | 1011篇 |
眼科学 | 415篇 |
药学 | 468篇 |
中国医学 | 744篇 |
肿瘤学 | 295篇 |
出版年
2024年 | 42篇 |
2023年 | 129篇 |
2022年 | 287篇 |
2021年 | 378篇 |
2020年 | 300篇 |
2019年 | 275篇 |
2018年 | 280篇 |
2017年 | 344篇 |
2016年 | 331篇 |
2015年 | 303篇 |
2014年 | 506篇 |
2013年 | 488篇 |
2012年 | 417篇 |
2011年 | 469篇 |
2010年 | 366篇 |
2009年 | 403篇 |
2008年 | 344篇 |
2007年 | 335篇 |
2006年 | 308篇 |
2005年 | 280篇 |
2004年 | 231篇 |
2003年 | 223篇 |
2002年 | 198篇 |
2001年 | 170篇 |
2000年 | 144篇 |
1999年 | 110篇 |
1998年 | 99篇 |
1997年 | 115篇 |
1996年 | 103篇 |
1995年 | 83篇 |
1994年 | 84篇 |
1993年 | 77篇 |
1992年 | 78篇 |
1991年 | 82篇 |
1990年 | 72篇 |
1989年 | 80篇 |
1988年 | 58篇 |
1987年 | 50篇 |
1986年 | 53篇 |
1985年 | 66篇 |
1984年 | 56篇 |
1983年 | 34篇 |
1982年 | 32篇 |
1981年 | 51篇 |
1980年 | 39篇 |
1979年 | 25篇 |
1978年 | 23篇 |
1977年 | 17篇 |
1976年 | 11篇 |
1975年 | 9篇 |
排序方式: 共有9082条查询结果,搜索用时 15 毫秒
71.
SUMMARY The wavelet transform is a relatively new approach to data processing which has been applied in different areas such as signal, speech and image processing. In the last decade, many papers have been published on wavelet theory and its applications. The wavelet transform provides an elegant alternative to the classical Fourier or Gabor transforms unifying numerous signal processing techniques in a common framework. The purpose of the present paper is to provide an overview of the applicability of the wavelet transform to EEG signal analysis. In the first part of the paper the mathematical background is summarized. In the second part, applications to the sleep EEG field are presented and discussed. The results of these illustrations demonstrate the usefulness of the wavelet transform to solve various problems including signal parametrization, pattern recognition and biosignal representation. 相似文献
72.
A. Le Tourneau J. Audouin J. Diebold 《Virchows Archiv : an international journal of pathology》1988,413(3):215-222
Summary The ultrastructural morphology of 4 cases of large anaplastic cell malignant lymphoma (Ana ML) is reported. Three cases were primary Ana ML and one pleomorphic large T cell lymphoma with some Ki-1 positive cells. All were confirmed by immunohistochemistry on frozen and paraffin sections. The Ki-1 and EMA positive tumour cells had an abundant cytoplasm, with no differentiation and large pale nuclei with multiple compact or dispersed nucleoli. The morphology is that of an activated cell engaged in protein synthesis and/or in the mitotic cycle. These tumour cells resemble to the Hodgkin's and monolobated Reed-Sternberg cells described in Hodgkin's disease. 相似文献
73.
父母教养方式:EMBU的初步修订及其在神经症患者的应用 总被引:141,自引:20,他引:141
岳冬梅 《中国心理卫生杂志》1993,7(3):97-101
本文选取390名正常人为被试,对父母教养方式调查问卷 EMBU (Egna Minnen avBarndosnauppforstran) 通过主因素分析,项目分析进行了初步修订。修订后的问卷涉及父亲58个条目。母亲57个条目,并各自由六个和五个分量表组成。并对66名神经症患者和66名正常人进行了效度的实证考查。 相似文献
74.
Salganik MP Hardie DL Swart B Dandie GW Zola H Shaw S Shapiro H Tinckam K Milford EL Wand MP 《Journal of immunological methods》2005,305(1):67-74
The blind panel collected for the 8th Human Leucocyte Differentiation Antigens Workshop (HLDA8; ) included 49 antibodies of known CD specificities and 76 antibodies of unknown specificity. We have identified groups of antibodies showing similar patterns of reactivity that need to be investigated by biochemical methods to evaluate whether the antibodies within these groups are reacting with the same molecule. Our approach to data analysis was based on the work of Salganik et al. (in press) [Salganik, M.P., Milford E.L., Hardie D.L., Shaw, S., Wand, M.P., in press. Classifying antibodies using flow cytometry data: class prediction and class discovery. Biometrical Journal]. 相似文献
75.
An automated method was used to record the temporal pattern of feeding of lines of mice selected over 15 generations for high and low body weight (L-mice and S-mice, respectively). Both L-mice and S-mice eat in meals concentrated during the night, and meal frequency is similar in the two lines, but L-mice consume much larger meals, each made up of many more separate feeding bouts. The outbred strain from which the selected lines were derived has a similar basic pattern of feeding in meals, which becomes like that of L-mice when the animal's thermogenic metabolic rate is high, and like that of S-mice when it is low, suggesting that the differences between the feeding patterns of the two selected lines are a secondary consequence of alterations in whole body metabolic rate. 相似文献
76.
The Popdc2 gene is a member of the Popeye domain containing gene family encoding membrane proteins with prominent expression in striated and smooth muscle tissue. After introducing a LacZ reporter gene into the Popdc2 locus, expression was studied during embryonic development and postnatal life. At embryonic day (E) 7.5, expression was present in cardiac and extraembryonic mesoderm. At E10.5, expression was found in heart, somites, and mesothelial cells lining the coelom. At E12.5, expression was present in the coelomic mesothelium, pericardial and myocardial layer of the heart, skeletal muscle, bladder, gut, and umbilical vessels. Postnatal expression was found in cardiac and skeletal muscle and in the smooth muscle layer of colon, rectum, and bladder. In the stomach, Popdc2 was exclusively present in the pyloric epithelium. In conclusion, Popdc2 is expressed in various muscle and nonmuscle cell types during embryonic development and in postnatal life. 相似文献
77.
Pericentric inversions of chromosome 4: report of a new family and review of the literature 总被引:1,自引:0,他引:1
A. Villa M. Urioste M. C. Carrascosa S. Vázquez A. Martínez M. L. Martínez-Frías 《Clinical genetics》1995,48(5):255-260
A family was cytogenetically studied because of the birth of a male child with a multiple congenital anomaly pattern, in whom a dup (4q) recombinant was found. His phenotypically normal mother's karyotype showed an apparently balanced pericentric inversion in a chromosome 4. So as to analyze the occurrence of recombinants, the cytogenetic data from this family are compared with those of the 18 previously reported familial cases of pericentric inversions (PIs) of chromosome 4. The congenital anomalies observed in the child strongly suggest Wolf-Hirschhorn syndrome but some of his clinical features seem to be pathogenetically related to the presence of lymphedema during the intrauterine period. In the multiple congenital anomaly pattern observed in this patient, the lymphedema could be the consequence of the large 4q duplication. The review of chromosome 4 PIs with 4q duplication suggests that the q3 region should be examined when edema is detected prenatally. 相似文献
78.
Sleep on the Night Shift: 24-Hour EEG Monitoring of Spontaneous Sleep/Wake Behavior 总被引:12,自引:0,他引:12
Lars Torsvall Torbjöurn Akerstedt Katja Gillander Anders Knutsson 《Psychophysiology》1989,26(3):352-358
The present study sought to objectively describe the spontaneous sleep/wakefulness pattern of shift workers during a 24-hour period. Portable Medilog tape-recorders were used for ambulatory EEG monitoring of 25 male papermill workers (25-55 years) during days with night and afternoon work. The results showed that sleep after night work was two hours shorter than after afternoon work. The sleep reduction affected mainly Stage 2 and REM sleep while slow wave sleep was unchanged. In connection with night work 28% of the workers took a nap in the afternoon. These naps contained a large proportion of slow wave sleep and were, apparently, caused by the sleep deficit after the short main sleep period. The EEG recordings also revealed that 20% of the participants had sleep episodes during night work. These naps were as long as the afternoon naps, were experienced as "dozing offs" rather than naps, occurred at the time of the trough of the circadian wakefulness rhythm, and were concomitant with extreme subjective sleepiness and low rated work load. It was concluded that not only the sleep of shift workers was disturbed, but also the wakefulness--to the extent that sleepiness during night work sometimes reached a level where reasonable wakefulness could not be maintained. The latter observation is probably of special importance in work situations demanding a great responsibility for human lives or for great economic values. 相似文献
79.
The present study was designed to compare the differential cardiopulmonary and hemodynamic responses of Type A and B women to an exercise and a psychological stressor. In addition, the effects of menstrual cycle phase on the resting and response levels of a wide range of physiological variables were explored. Thirty-two women participated in a progressive exercise stress test and a threat of shock video game during both the luteal and follicular phases of the menstrual cycle. Half of these subjects expressed the coronary-prone behavior pattern referred to as Type A, as assessed by the Jenkins Activity Survey. The remaining women were relatively free of these behaviors (Type B). Heart rate, oxygen consumption, carbon dioxide production, minute ventilation, and end-tidal carbon dioxide were monitored and recorded on a breath-by-breath basis. Systolic and diastolic blood pressure measures were taken at 2-min intervals. Results indicated similar baseline, exercise, and behavioral stress responses among Type A and B women. The stress responses were also the same between the follicular and luteal phases for all measured physiological variables. However, resting levels of heart rate, metabolism, and ventilation were all elevated at rest during the luteal phase. A regression analysis based on the exercise heart rate and oxygen consumption data demonstrated that a majority of subjects exhibited heart rate responses in excess of that expected during the psychological stressor. These data are discussed with special reference to possible mechanisms of the pathophysiology of cardiovascular disease. 相似文献
80.
介绍了用图像处理及模式识别技术对显微细胞图像的自动分析和分类的方法,并针对医学图像分析中的难点,提出了基于归一化彩色空间和RGB,HSV彩色模型的分割方法:利用模式识别技术中关于特征向量空间聚类的方法实施真彩色分割.这种方式有效地利用了多维特征空间对于分割目标所提供的信息,使分割的准确性有了较大的提高,解决了图像分割过程中的单个细胞检出问题. 相似文献