全文获取类型
收费全文 | 1505篇 |
免费 | 57篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 53篇 |
儿科学 | 40篇 |
妇产科学 | 34篇 |
基础医学 | 185篇 |
口腔科学 | 38篇 |
临床医学 | 116篇 |
内科学 | 348篇 |
皮肤病学 | 11篇 |
神经病学 | 120篇 |
特种医学 | 59篇 |
外科学 | 223篇 |
综合类 | 7篇 |
预防医学 | 74篇 |
眼科学 | 7篇 |
药学 | 60篇 |
中国医学 | 1篇 |
肿瘤学 | 192篇 |
出版年
2023年 | 6篇 |
2022年 | 21篇 |
2021年 | 35篇 |
2020年 | 13篇 |
2019年 | 18篇 |
2018年 | 26篇 |
2017年 | 26篇 |
2016年 | 32篇 |
2015年 | 26篇 |
2014年 | 39篇 |
2013年 | 68篇 |
2012年 | 101篇 |
2011年 | 128篇 |
2010年 | 68篇 |
2009年 | 77篇 |
2008年 | 100篇 |
2007年 | 107篇 |
2006年 | 125篇 |
2005年 | 83篇 |
2004年 | 108篇 |
2003年 | 81篇 |
2002年 | 67篇 |
2001年 | 32篇 |
2000年 | 21篇 |
1999年 | 22篇 |
1998年 | 14篇 |
1997年 | 9篇 |
1996年 | 12篇 |
1995年 | 4篇 |
1994年 | 15篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1969年 | 3篇 |
1968年 | 3篇 |
1967年 | 2篇 |
排序方式: 共有1568条查询结果,搜索用时 18 毫秒
1.
2.
3.
4.
PURPOSE: Digoxin is the third most commonly prescribed drug, yet limited information exists about its use in outpatients. Therefore, 242 medical outpatients receiving digoxin at our hospital were studied to evaluate the appropriateness of its use, defined by: (1) current or past supraventricular arrhythmias and/or (2) left ventricular systolic dysfunction (ejection fraction less than 45 percent). PATIENTS AND METHODS: Charts of 242 patients receiving digoxin were obtained. The patients were divided into groups based upon their physician's stated indication for digoxin therapy. Patients with only a clinical diagnosis of congestive heart failure (CHF) underwent echocardiography or radionuclide angiography to quantify left ventricular systolic function. Those with documented supraventricular arrhythmias and/or those with confirmed left ventricular systolic dysfunction were classified as appropriate candidates for digoxin. RESULTS: Ninety-five percent of patients received digoxin for appropriate indications; 75 percent had confirmed supraventricular arrhythmias (27 percent also had CHF) and 20 percent with normal sinus rhythm had documented systolic dysfunction. However, physicians had difficulty in the clinical assessment of left ventricular function; 18 percent of patients with sinus rhythm and CHF by the Framingham scoring system and 20 percent of those with supraventricular arrhythmias and CHF had preserved systolic function. An S3 was present in 15 percent of patients with preserved ejection fraction and CHF and in 69 percent with low ejection fraction; hypertension was significantly more common in the former group. Noninvasive assessment of systolic function was obtained in 97 percent of patients independent of this study, yet some patients without supraventricular arrhythmias and with documented preservation of systolic function continued to receive the drug. CONCLUSION: Noninvasive assessment of left ventricular function, which appears to have become routine, is of value in the appropriate utilization of digoxin, since clinicians' assessment of left ventricular function may be inaccurate. Physicians also do not always discontinue digoxin therapy when indicated. 相似文献
5.
Cortical spreading depression in the feline brain following sustained and transient stimuli studied using diffusion-weighted imaging 总被引:1,自引:0,他引:1
6.
Richard F. Lee Kurt C. Pice Vassilis C. Stamoudis 《Archives of environmental contamination and toxicology》1988,17(5):651-656
A liquid Chromatograph equipped with a short (3 cm) reverse phase column and electrochemical detector was used to characterize aromatic amines in shale oil, synthetic oil, and coal gasification streams. Five major peaks were produced from each sample mixture. The composition of the peaks was determined by high performance liquid chromatography with a long (25 cm) reverse phase column and by gas chromatography/mass spectrometry. Amines in the various peaks included aminonaphthalenes, aminobiphenyls, aminofluorenes, and aminophenanthrenes plus aminoanthracenes. The concentration of aminofluorenes, and aminophenanthrenes plus aminoanthracenes correlated with relative mutagenicity of the base fraction from the oils or tars. The levels of 2- and 3-ringed aromatic amines from shale oil and oil from the Great Plains commercial coal gasification plan were 24 and 184 g/g tar, respectively, while the respective mutagenicities were 8 and 214 revertants/g base fraction. This technique has the advantages of high sensitivity and rapid analysis, and could be used to screen for the presence of mutagens in synthetic fuel samples. 相似文献
7.
We investigated the properties of neurons located in the distal forelimb field of dorsal premotor area F2 of macaque monkey using a behavioral paradigm for studying the neuronal discharge during observation (object fixation condition) and grasping of different 3-dimensional objects with and without visual guidance of the movement (movement in light and movement in dark conditions, respectively). The main result is that almost all studied neurons were selective for both the type of prehension and the wrist orientation required for grasping an object. Three categories of neurons were found: purely motor, visually modulated, and visuomotor neurons. The discharge of purely motor neurons was not affected by either object presentation or by the visual feedback of the hand approaching to and interacting with the object. Visually modulated neurons presented a different discharge in the 2 movement conditions, this determining a decrease in selectivity for the grip and wrist orientation in the movement in dark condition. Visuomotor neurons typically discharged during the object fixation task even in the absence of any grasping movement. Nine of them also displayed a different discharge rate between the 2 movement conditions. Congruence was observed between the neuron response during the most effective type of prehension and the neuron response during observation of the object requiring that particular prehension. These results indicate an important role of F2 in the control of goal-related hand movements. 相似文献
8.
C. Grigoreas D. Pappas I. D. Galatas G. Kollias S. Papadimos P. Papadakis 《Allergy》1993,48(3):142-146
The distribution of IgE in a large randomly stratified Greek population sample was determined in 1187 subjects (793 men and 394 women) aged between 20 and 60 years. Skin prick testing was performed and serum total IgE expressed in iu/ml was measured by Phadebas PRIST: the data are presented as the geometric mean. Subjects were classified as atopic (257 men, 118 women) and nonatopic (536 men, 276 women) according to the results of skin testing with various aeroallergens. At any age, atopic males (120.5 vs 38 iu/ml) and females (99.8 vs 29.3 iu/ml) had higher mean IgE levels, as compared to nonatopic subjects ( P <0.0001). In our adult nonatopic sample, IgE levels did not differ with age ( P >0.05). At any age, nonatopic males had higher (38 iu/ml) mean IgE levels than nonatopic females (29.3 iu/ml) ( P <0.05). The comparison of normal IgE values (nonatopic subjects) from this study with those reported by other investigators revealed that Greek adult males and females had higher IgE levels than populations from other nations. Our results represent the first report on reference values regarding serum total IgE in Greek adults. 相似文献
9.
M. E. De Paepe Konstantinos Papadakis Brian D. Johnson Francois I. Luks 《Virchows Archiv : an international journal of pathology》1998,432(1):7-16
Tracheal occlusion in utero has been shown to cause accelerated fetal lung growth and is now being considered as a therapeutic
modality for pulmonary hypoplasia. We report the effects of tracheal ligation on the surfactant-producing type II pneumocyte
population. Three groups of fetal lambs underwent tracheal ligation of 2 weeks’, 4 weeks’ and 6 weeks’ duration, respectively,
and all were sacrificed at 136 days’ gestation (9 days pre-term). Nonoperated twins served as controls. The type II pneumocyte
population was studied morphometrically using a combination of anti-surfactant protein B immunohistochemistry and computer-assisted
stereologic morphometry at light and electron microscopic levels. Single-factor ANOVA was used for statistical analysis. Two
weeks of tracheal ligation resulted in doubling of the total lung volume as a result of airspace distension and, to lesser
extent, growth of the tissue compartment. With increasing duration of tracheal ligation, there was no additional lung growth.
However, more prolonged tracheal occlusion was found to result in significant reduction of the surfactant system, as reflected
in the marked decrease of total pneumocyte type II volume (3.14 cm3, 0.95 cm3, and 0.46 cm3, after 2, 4, and 6 weeks of ligation, compared with 5.96 cm3 for controls) and total pneumocyte type II number (13.9 × 109, 3.8 × 109, and 2.4 × 109, compared with 53.2 × 109 for controls). Ultrastructural analysis of the type II cells in obstructed lungs showed vacuolar degenerative changes that,
after 6 weeks of ligation, were apparently irreversible. In utero tracheal ligation causes fetal lung hyperplasia, but results
in reduction of and injury to the surfactant-producing cell population. Before tracheal occlusion can find widespread clinical
application, its pathophysiology needs to be further elucidated.
Received: 30 April 1997 / Accepted: 10 July 1997 相似文献
10.
J A Papadakis D Trichopoulos N Papaiconomou D Karalis P Vassiliadis 《Bulletin de la Societe de pathologie exotique (1990)》1975,68(2):151-152
A new Salmonella serotype, of sub-genus II, Salmonella 3,10 : 1,z28 : 1.5, has been isolated in Greece from refrigerated minced meat imported from South America. 相似文献