全文获取类型
收费全文 | 599篇 |
免费 | 42篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 38篇 |
妇产科学 | 1篇 |
基础医学 | 83篇 |
口腔科学 | 17篇 |
临床医学 | 76篇 |
内科学 | 124篇 |
皮肤病学 | 20篇 |
神经病学 | 27篇 |
特种医学 | 124篇 |
外科学 | 39篇 |
综合类 | 12篇 |
预防医学 | 34篇 |
眼科学 | 1篇 |
药学 | 27篇 |
肿瘤学 | 36篇 |
出版年
2022年 | 3篇 |
2021年 | 14篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 7篇 |
2016年 | 8篇 |
2015年 | 13篇 |
2014年 | 14篇 |
2013年 | 20篇 |
2012年 | 9篇 |
2011年 | 16篇 |
2010年 | 32篇 |
2009年 | 40篇 |
2008年 | 11篇 |
2007年 | 31篇 |
2006年 | 18篇 |
2005年 | 19篇 |
2004年 | 13篇 |
2003年 | 4篇 |
2002年 | 7篇 |
2001年 | 11篇 |
2000年 | 4篇 |
1999年 | 10篇 |
1998年 | 36篇 |
1997年 | 37篇 |
1996年 | 31篇 |
1995年 | 30篇 |
1994年 | 11篇 |
1993年 | 20篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1990年 | 11篇 |
1989年 | 13篇 |
1988年 | 19篇 |
1987年 | 17篇 |
1986年 | 9篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 13篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1978年 | 9篇 |
1977年 | 8篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1966年 | 2篇 |
1957年 | 2篇 |
1954年 | 2篇 |
排序方式: 共有662条查询结果,搜索用时 31 毫秒
41.
42.
Diet and cancer prevention: the fiber first diet 总被引:3,自引:0,他引:3
Diet can play a major role in cancer prevention. The international
differences in cancer incidence are largely accounted for by lifestyle
practices that include nutrition, exercise, and alcohol and tobacco use.
About 50% of cancer incidence and 35% of cancer mortality in the U.S.,
represented by cancers of the breast, prostate, pancreas, ovary,
endometrium, and colon, are associated with Western dietary habits. Cancer
of the stomach, currently a major disease in the Far East, relates to
distinct, specific nutritional elements such as excessive salt intake. For
these cancers, information is available on possible initiating genotoxic
factors, promoting elements, and prophylactic agents. In general, the
typical diet in the United States contains low levels of the potent
carcinogenic agents, heterocyclic amines, formed during the cooking of
meats. It provides only about half the potent appropriate fiber intake and
is high in calories. About twice as many calories as would be desirable
come from fat, certain kinds of which enhance the development of cancers.
Other foods with functional properties, such as soy products and tea, can
be beneficial. To achieve reduction in risk of certain cancers, diet must
be optimized, primarily to reduce caloric intake and the fat component. The
latter should be 20% or less of total caloric intake and fiber should be
increased to 25- 35 g per day for adults. One approach to achieving these
goals is the Fiber First Diet, a diet designed around adequate fiber intake
from grains, especially cereals, vegetables, legumes, and fruits, which
thereby reduces both calorie and fat intake. Such dietary improvements will
not only reduce cancer and other chronic disease risks, but will contribute
to a healthy life to an advanced age. A corollary benefit is a lower cost
of medical care.
相似文献
43.
GM Durbin NJ Hunter N McIntosh EO Reynolds PD Wimberley 《Archives of disease in childhood》1976,51(3):163-169
A controlled trial of elective intervention with continuous inflating pressure (CIP) was performed in infants with severe hyaline membrane disease who weighed more than 1000 g at birth. Infants entered the trial if their arterial oxygen tension (PaO2) fell below 60 mmHg while breathing a fractional inspired oxygen concentration (F1O2) greater than 0-95. 11 out of 12 infants in the CIP-treated group and 10 out of 12 in the control group survived. 7 treated and 6 control infants required mechanical ventilation. When CIP was started the Pao2 of the treated infants increased, and they breathed high concentrations of oxygen for a significantly shorter period than the control infants. During the 31-month duration of the trial 107 other infants with severe hyaline membrane disease were admitted who did not meet the criteria for entry to the trial. 37 survived after breathing high concentrations of oxygen (F1O2 greater than 0-60) spontaneously without any ventilatory assistance, and the remaining 70 infants were already being ventilated on their arrival in the unit, usually because they had required mechanical ventilation during transfer from other hospitals. The neonatal survival rate for those infants born in this hospital during the study period was 88% (50 out of 57 infants) and for those referred from other hospitals it was 69% (51 out of 74 infants). The maximum further increase in overall survival rate that might have been achieved in our population of infants if CIP had been initiated very early in the course of the illness was 5%--i.e. from 77% (101/131) to 82% (107/131). 相似文献
44.
45.
46.
Postbiopsy renal transplant arteriovenous fistulas: color Doppler US characteristics 总被引:3,自引:0,他引:3
Color Doppler ultrasound (US) with point-spectral analysis was performed on eight patients with postbiopsy renal transplant arteriovenous fistulas. Waveform analysis of the supplying artery documented decreased resistive indices in all cases and increased flow velocities in seven. The peak-systolic flow velocity in the arteries supplying the fistulas ranged from 55 to 180 cm/sec (mean, 92 cm/sec), while the range in normal arteries was 20-52 cm/sec (mean, 32 cm/sec). The resistive indices of the arteries supplying the fistulas ranged from 0.31 to 0.50 (mean, 0.45), while the resistive indices of the normal arteries ranged from 0.60 to 0.92 (mean, 0.74). Arterialization of the venous waveform from the draining vein was also documented in all cases. In six cases, the increased flow velocities resulted in increased color saturation toward white in the supplying artery (n = 2) or in both the artery and the draining vein (n = 4), which was detectable on the realtime image. In six cases, flow turbulence resulted in localized tissue vibration, which appeared as random color assignment in extravascular renal parenchyma adjacent to the fistula. Knowledge of these imaging and Doppler characteristics should aid in the identification of renal transplant arteriovenous fistulas with color Doppler US. 相似文献
47.
Aimée E van Dijk Manon van Eijsden Karien Stronks Reinoud JBJ Gemke Tanja GM Vrijkotte 《BMC public health》2010,10(1):251
Background
Recent evidence, both animal and human, suggests that modifiable factors during fetal and infant development predispose for cardiovascular disease in adult life and that they may become possible future targets for prevention. One of these factors is maternal psychosocial stress, but so far, few prospective studies have been able to investigate the longer-term effects of stress in detail, i.e. effects in childhood. Therefore, our general aim is to study whether prenatal maternal psychosocial stress is associated with an adverse cardio-metabolic risk profile in the child at age five. 相似文献48.
49.
Front D; Ioselevsky G; Frenkel A; Even-Sapir E; Israel O; Kolodny GM; Feinsud M 《Radiology》1987,164(1):93-96
A single photon emission computed tomographic method was designed for the measurement of radiopharmaceutical uptake in brain tumors. Results of phantom studies showed a correlation coefficient of .99 when measured volume was compared with actual volume. The correlation coefficient for measured radioactivity concentration compared with the actual concentration was .97. In 13 meningiomas the correlation between in vivo SPECT measurements of uptake and in vitro measurements in samples of the same tumors removed surgically was .84; when two tumors that contained regions of necrosis and fibrosis were excluded it was .93. This method can be used for in vivo quantitative assessment of pharmacokinetics of labeled drug uptake in human brain tumors. 相似文献
50.