全文获取类型
收费全文 | 2075284篇 |
免费 | 151905篇 |
国内免费 | 4267篇 |
专业分类
耳鼻咽喉 | 28942篇 |
儿科学 | 70124篇 |
妇产科学 | 59797篇 |
基础医学 | 301988篇 |
口腔科学 | 58714篇 |
临床医学 | 182483篇 |
内科学 | 402598篇 |
皮肤病学 | 45386篇 |
神经病学 | 162985篇 |
特种医学 | 80762篇 |
外国民族医学 | 652篇 |
外科学 | 315598篇 |
综合类 | 46537篇 |
现状与发展 | 1篇 |
一般理论 | 653篇 |
预防医学 | 157856篇 |
眼科学 | 47952篇 |
药学 | 154480篇 |
4篇 | |
中国医学 | 4079篇 |
肿瘤学 | 109865篇 |
出版年
2018年 | 20493篇 |
2016年 | 17799篇 |
2015年 | 20265篇 |
2014年 | 27913篇 |
2013年 | 42694篇 |
2012年 | 57318篇 |
2011年 | 61399篇 |
2010年 | 36657篇 |
2009年 | 34485篇 |
2008年 | 58554篇 |
2007年 | 62833篇 |
2006年 | 63901篇 |
2005年 | 61882篇 |
2004年 | 59992篇 |
2003年 | 58077篇 |
2002年 | 56698篇 |
2001年 | 93671篇 |
2000年 | 95908篇 |
1999年 | 81121篇 |
1998年 | 23191篇 |
1997年 | 20810篇 |
1996年 | 20986篇 |
1995年 | 19998篇 |
1994年 | 18842篇 |
1993年 | 17474篇 |
1992年 | 65634篇 |
1991年 | 64562篇 |
1990年 | 63771篇 |
1989年 | 61712篇 |
1988年 | 56946篇 |
1987年 | 56442篇 |
1986年 | 53338篇 |
1985年 | 51194篇 |
1984年 | 38428篇 |
1983年 | 32981篇 |
1982年 | 19775篇 |
1981年 | 17633篇 |
1979年 | 36083篇 |
1978年 | 25728篇 |
1977年 | 22036篇 |
1976年 | 20909篇 |
1975年 | 22444篇 |
1974年 | 26756篇 |
1973年 | 25818篇 |
1972年 | 24174篇 |
1971年 | 22589篇 |
1970年 | 20959篇 |
1969年 | 19903篇 |
1968年 | 18599篇 |
1967年 | 16534篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
132.
The age association and alterations in vascular structure and function at both the cellular and molecular levels are increasingly recognized as major risk factors for CV disease. The arterial remodeling during aging that may be enhanced by the CV risk factors are supersensitive to the age-related risk factors. The aging process may well be influenced by a combination of hereditary and environmental factors. Much can be done to modify environmental risk factors, very little to genetics except for choosing your parents. 相似文献
133.
134.
The influence of short‐term confinement and moderate exercise on tibia development was investigated in growing pigs (36–41 kg, 10 weeks at the beginning of the study). Animals were kept for 2 weeks either in individual crates of 0.8 m2 (‘confinement’, n = 4) or kept in groups of four animals in large crates of 5.6 m2 without (‘control’) or with additional exercise (30 min walking at 5 days/week; ‘exercise’). Bone density and morphological parameters were evaluated by computer tomography (CT). Periosteal apposition and longitudinal growth were determined after polychrome sequential labelling in weekly intervals. Cortical areas of the cross sections at the mid‐shaft and at 75% of the length of the bone measured distal to the carpus by CT were significantly correlated to each other (r = 0.70) and revealed a significant reduction in confined animals. This difference was explained by lower periosteal apposition rates in these animals compared with exercised and group‐housed pigs. Similarly longitudinal growth and the formation and calcification of spongiosa of the tibiae were inhibited by confinement. Thus, 2 weeks of confinement led to significant differences in bone growth and metabolism in young growing piglets when compared with animals with moderate activity. 相似文献
135.
Abstract Chorea is a rare complication of polycythaemia vera. Polycythaemic chorea occurs predominantly in females and usually in generalised
form. We present a 66-year-old woman with acute onset hemichorea-ballism with no vascular pathology in the basal ganglia region.
A clear relationship was observed between the onset of chorea and worsening of haematological parameters in the patient. After
repeated phlebotomies the patient's clinical status was improved. Polycythaemic chorea must be considered, especially in the
elderly, as early diagnosis leads to effective treatment and prevention of complications. 相似文献
136.
F Piccione F Giorgi P Tonin K Priftis S Giove S Silvoni G Palmas F Beverina 《Clinical neurophysiology》2006,117(3):531-537
OBJECTIVE: This study aimed to describe the use of the P300 event-related potential as a control signal in a brain computer interface (BCI) for healthy and paralysed participants. METHODS: The experimental device used the P300 wave to control the movement of an object on a graphical interface. Visual stimuli, consisting of four arrows (up, right, down, left) were randomly presented in peripheral positions on the screen. Participants were instructed to recognize only the arrow indicating a specific direction for an object to move. P300 epochs, synchronized with the stimulus, were analyzed on-line via Independent Component Analysis (ICA) with subsequent feature extraction and classification by using a neural network. RESULTS: We tested the reliability and the performance of the system in real-time. The system needed a short training period to allow task completion and reached good performance. Nonetheless, severely impaired patients had lower performance than healthy participants. CONCLUSIONS: The proposed system is effective for use with healthy participants, whereas further research is needed before it can be used with locked-in syndrome patients. SIGNIFICANCE: The P300-based BCI described can reliably control, in 'real time', the motion of a cursor on a graphical interface, and no time-consuming training is needed in order to test possible applications for motor-impaired patients. 相似文献
137.
138.
139.
140.
N. N. Polygalova A. G. Mikhailovskii E. S. Limanskii B. Ya. Syropyatov M. I. Vakhrin 《Pharmaceutical Chemistry Journal》2006,40(3):132-134
A series of 1-alkyl-3,4-dihydroisoquinolines and the related 4-alkyl-1,2-dihydro-benzo[f]isoquinolines was synthesized using
reactions of dialkylbenzylcarbinols and their naphthyl analogs with alkylcyanides. Experiments showed that 1-alkyl-6,7-dimethoxy-3,4-dihydroisoquinolines
typically produce a hypotensive action, while the benzo-annelated structures usually exhibit a hypertensive effects. The most
active compound decreases the arterial pressure in cats by 52 Torr and the effect lasts for about 4 hours.
__________
Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 3, pp. 15–17, March, 2006. 相似文献