全文获取类型
收费全文 | 19846篇 |
免费 | 1653篇 |
国内免费 | 325篇 |
专业分类
耳鼻咽喉 | 71篇 |
儿科学 | 1925篇 |
妇产科学 | 1976篇 |
基础医学 | 1596篇 |
口腔科学 | 200篇 |
临床医学 | 1883篇 |
内科学 | 2529篇 |
皮肤病学 | 61篇 |
神经病学 | 1020篇 |
特种医学 | 315篇 |
外科学 | 1200篇 |
综合类 | 2121篇 |
现状与发展 | 1篇 |
一般理论 | 2篇 |
预防医学 | 3799篇 |
眼科学 | 164篇 |
药学 | 2012篇 |
8篇 | |
中国医学 | 485篇 |
肿瘤学 | 456篇 |
出版年
2024年 | 52篇 |
2023年 | 366篇 |
2022年 | 549篇 |
2021年 | 983篇 |
2020年 | 749篇 |
2019年 | 855篇 |
2018年 | 765篇 |
2017年 | 801篇 |
2016年 | 837篇 |
2015年 | 744篇 |
2014年 | 1315篇 |
2013年 | 1715篇 |
2012年 | 1083篇 |
2011年 | 1232篇 |
2010年 | 945篇 |
2009年 | 913篇 |
2008年 | 986篇 |
2007年 | 902篇 |
2006年 | 749篇 |
2005年 | 693篇 |
2004年 | 554篇 |
2003年 | 513篇 |
2002年 | 389篇 |
2001年 | 328篇 |
2000年 | 289篇 |
1999年 | 216篇 |
1998年 | 201篇 |
1997年 | 168篇 |
1996年 | 140篇 |
1995年 | 132篇 |
1994年 | 132篇 |
1993年 | 110篇 |
1992年 | 109篇 |
1991年 | 96篇 |
1990年 | 88篇 |
1989年 | 69篇 |
1988年 | 73篇 |
1987年 | 62篇 |
1986年 | 71篇 |
1985年 | 133篇 |
1984年 | 109篇 |
1983年 | 90篇 |
1982年 | 73篇 |
1981年 | 76篇 |
1980年 | 69篇 |
1979年 | 65篇 |
1978年 | 53篇 |
1977年 | 32篇 |
1976年 | 41篇 |
1973年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Summary Insulin binding to trophoblast plasma membranes and the placental glycogen content were measured in twelve healthy women, in eleven well-controlled gestational diabetic women who were treated either with diet alone (n=4) or with insulin (n=7) and in 18 women with well-controlled overt diabetes mellitus (six White B; four White C; eight White D). The competitive binding assay was carried out with 22 concentrations of unlabelled insulin. Binding data were analysed by a non-linear direct model fitting procedure assuming one non-cooperative binding site. Maximum specific binding was unchanged in the total collective of gestational diabetic women, but was decreased by 30% in those treated with diet (6.2±2.2%) and increased by 90% in insulin-treated women (16.4±10.2%) as compared to the control subjects (8.7±2.5%). The diet-treated women had only 40% as many and those treated with insulin had more than twice as many receptors compared to control subjects on a per mg protein basis and if expressed per total placenta. In patients with overt diabetes mellitus maximum specific binding (18.5±10.6 %) was higher (p<0.05) due to more receptors compared to control subjects but was similar to the insulin-treated gestational diabetic patients. Maximum specific binding and receptor concentrations did not correlate linearly with maternal plasma insulin levels. Receptor affinities were virtually similar in all groups (1.8·109 l/mol). The placental glycogen content was reduced (p<0.05) to about 80% of that of control subjects in the diet-treated collective, whereas it was unchanged compared to control subjects in the insulin-treated gestational diabetic women despite a 40% increase (p<0.001) of the maternal-to-cord serum glucose ratio. In overt diabetic patients the maternal-to-cord serum glucose ratio and the placental glycogen content were higher (p<0.05) than in the control subjects. We conclude that trophoblast plasma membranes from gestational diabetic women treated with diet alone express less and those from women treated with insulin express more insulin receptors than those from a healthy control group in vitro. These differences could not have been disclosed without consideration of the mode of treatment. Trophoblast plasma membranes from overt diabetic women have more insulin receptors than those from healthy control subjects. 相似文献
63.
64.
讨论了强酸、强碱中和过程PH控制方案。以0.9mol/L的NaoH中和0.9mol/L的HNO3,流量增量为0.1-0.3kg/min,用模糊控制将PH控制在各要求的值上,ΔpH≤0.2,获得满意的结果。 相似文献
65.
High-protein Weight-loss Diets: Are They Safe and Do They Work? A Review of the Experimental and Epidemiologic Data 总被引:6,自引:0,他引:6
Julie Eisenstein M.D. Susan B. Roberts Ph.D. Gerard Dallal Ph.D. Edward Saltzman M.D. 《Nutrition reviews》2002,60(7):189-200
Recommendations for increased consumption of protein are among the most common approaches of popular or fad diets. This review summarizes the effects of dietary protein on satiety, energy intake, thermogenesis, and weight loss, as well as its effect on a variety of health outcomes in adults. In short-term studies, dietary protein modulates energy intake via the sensation of satiety and increases total energy expenditure by increasing the thermic effect of feeding. Whereas these effects did not contribute to weight and fat loss in those studies in which energy intake was fixed, one ad libitum study does suggest that a high-protein diet results in a greater decrease in energy intake, and therefore greater weight and fat loss. In terms of safety, there is little long-term information on the health effects of high-protein diets. From the available data, however, it is evident that the consumption of protein greater than two to three times the U.S. Recommended Daily Allowance contributes to urinary calcium loss and may, in the long term, predispose to bone loss. Caution with these diets is recommended in those individuals who may be predisposed to nephrolithiasis or kidney disease, and particularly in those with diabetes mellitus. 相似文献
66.
67.
Alister Oliver Mark Wright Andrew Matson Graham Woodrow Neil King Louise Dye 《Nephrology, dialysis, transplantation》2004,19(11):2883-2885
BACKGROUND: Interdialytic weight gain (IDWG) can be reduced by lowering the dialysate sodium concentration ([Na]) in haemodialysis patients. It has been assumed that this is because thirst is reduced, although this has been difficult to prove. We compared thirst patterns in stable haemodialysis patients with high and low IDWG using a novel technique and compared the effect of low sodium dialysis (LSD) with normal sodium dialysis (NSD). METHODS: Eight patients with initial high IDWG and seven with low IDWG completed hourly visual analogue ratings of thirst using a modified palmtop computer during the dialysis day and the interdialytic day. The dialysate [Na] was progressively reduced by up to 5 mmol/l over five treatments. Dialysis continued at the lowest attained [Na] for 2 weeks and the measurements were repeated. The dialysate [Na] then returned to baseline and the process was repeated. RESULTS: Baseline interdialytic day mean thirst was higher than the dialysis day mean for the high IDWG group (49.9+/-14.0 vs 36.2+/-16.6) and higher than the low weight gain group (49.9+/-14.0 vs 34.1+/-14.6). This trend persisted on LSD, but there was a pronounced increase in post-dialysis thirst scores for both groups (high IDWG: 46+/-13 vs 30+/-21; low IDWG: 48+/-24 vs 33+/-18). The high IDWG group demonstrated lower IDWG during LSD than NSD (2.23+/-0.98 vs 2.86+/-0.38 kg; P<0.05). CONCLUSIONS: Our results indicate that patients with high IDWG experience more intense feelings of thirst on the interdialytic day. LSD reduces their IDWG, but paradoxically increases thirst in the immediate post-dialysis period. 相似文献
68.
父母亲社会经济状况与低出生体质量儿的相关性探讨 总被引:1,自引:0,他引:1
①目的 探讨父母亲社会经济状况与低出生体质量儿发生的关系。②方法 采用病例对照研究方法,对190名低出生体质量儿和750名正常出生体质量儿的父母亲进行了相关因素调查,用Logistic回归分析进行了危险因素分析。③结果 母亲年龄大于35岁、母亲的职业为教师或农民、父亲吸烟、母亲孕期吸烟及年家庭收人低是发生低出生体质量儿的危险因素(OR=1.280~7.290),母亲身高与低出生体质量儿的发生率呈负相关关系(OR=0.898)。④结论 父母亲的社会经济状况与低出生体质量儿的发生有关。 相似文献
69.
A. Poobalan L. Aucott W. C. S. Smith A. Avenell R. Jung J. Broom A. M. Grant 《Obesity reviews》2004,5(1):43-50
This paper aims to review the evidence for long‐term effectiveness of weight loss on cholesterol, high‐density lipoprotein (HDL), low‐density lipoprotein (LDL) and triglycerides in overweight/obese people. Current evidence is mostly based on short‐term studies. A systematic review of long‐term lipid outcomes of weight loss in studies published between 1966 and 2001, was conducted. Inclusion criteria included all cohort studies and trials carried out on participants with body mass index of greater than or equal to 28 kg m?2. Studies had at least two weight change measurements and follow‐up of more than 2 years. Thirteen long‐term studies with a follow‐up of more than 2 years were included. Cholesterol has a significant positive linear relationship with weight change (r = 0.89) where change in weight explains about 80% of the cholesterol difference variation (Adj R2 = 0.80). For every 10 kg weight loss a drop of 0.23 mmol L?1 in cholesterol may be expected for a person suffering from obesity or are grossly overweight. Weight loss has long‐term beneficial effects especially on LDL and cholesterol. Weight loss in obese patients should be encouraged and sustained. 相似文献
70.
As part of a longitudinal developmental study of newborn and young Dutch twins, data on weight and height are collected. Birth weight and height are available for 3275 pairs; data on growth, for 1390 pairs. 相似文献