全文获取类型
收费全文 | 6324篇 |
免费 | 341篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 265篇 |
妇产科学 | 41篇 |
基础医学 | 904篇 |
口腔科学 | 64篇 |
临床医学 | 192篇 |
内科学 | 763篇 |
皮肤病学 | 13篇 |
神经病学 | 519篇 |
特种医学 | 63篇 |
外科学 | 339篇 |
综合类 | 193篇 |
预防医学 | 2393篇 |
眼科学 | 25篇 |
药学 | 744篇 |
中国医学 | 39篇 |
肿瘤学 | 137篇 |
出版年
2023年 | 79篇 |
2022年 | 88篇 |
2021年 | 415篇 |
2020年 | 217篇 |
2019年 | 241篇 |
2018年 | 213篇 |
2017年 | 160篇 |
2016年 | 162篇 |
2015年 | 211篇 |
2014年 | 273篇 |
2013年 | 508篇 |
2012年 | 219篇 |
2011年 | 323篇 |
2010年 | 219篇 |
2009年 | 233篇 |
2008年 | 256篇 |
2007年 | 203篇 |
2006年 | 172篇 |
2005年 | 160篇 |
2004年 | 150篇 |
2003年 | 137篇 |
2002年 | 102篇 |
2001年 | 86篇 |
2000年 | 84篇 |
1999年 | 77篇 |
1998年 | 75篇 |
1997年 | 68篇 |
1996年 | 50篇 |
1995年 | 63篇 |
1994年 | 40篇 |
1993年 | 47篇 |
1992年 | 59篇 |
1991年 | 62篇 |
1990年 | 55篇 |
1989年 | 43篇 |
1988年 | 62篇 |
1987年 | 38篇 |
1985年 | 103篇 |
1984年 | 129篇 |
1983年 | 90篇 |
1982年 | 103篇 |
1981年 | 78篇 |
1980年 | 91篇 |
1979年 | 86篇 |
1978年 | 75篇 |
1977年 | 57篇 |
1976年 | 60篇 |
1975年 | 58篇 |
1974年 | 41篇 |
1973年 | 34篇 |
排序方式: 共有6701条查询结果,搜索用时 468 毫秒
1.
2.
Eglantina Idrizaj Rachele Garella Roberta Squecco Maria Caterina Baccari 《World journal of gastroenterology : WJG》2020,26(20):2472-2478
The regulation of food intake is a complex mechanism, and the hypothalamus is the main central structure implicated. In particular, the arcuate nucleus appears to be the most critical area in the integration of multiple peripheral signals.Among these signals, those originating from the white adipose tissue and the gastrointestinal tract are known to be involved in the regulation of food intake.The present paper focuses on adiponectin, an adipokine secreted by white adipose tissue, which is reported to have a role in the control of feeding by acting centrally. The recent observation that adiponectin is also able to influence gastric motility raises the question of whether this action represents an additional peripheral mechanism that concurs with the central effects of the hormone on food intake. This possibility, which represents an emerging aspect correlating the central and peripheral effects of adiponectin in the hunger-satiety cycle, is discussed in the present paper. 相似文献
3.
4.
《Journal of the Academy of Nutrition and Dietetics》2022,122(6):1099-1113.e3
BackgroundLittle is known about breakfast habits of the Latin American (LA) population to support nutritional recommendations for a balanced breakfast in this region.ObjectiveTo evaluate the nutritional composition of breakfast in the LA population and to propose recommendations for a balanced breakfast.DesignThis multicenter cross-sectional study evaluated food and nutrient intake of nationally representative samples of urban populations of 8 LA countries (Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Peru, and Venezuela) in 2014-2015.Participants/settingThe sample comprised 8714 participants from the Latin American Study of Nutrition and Health, aged 15 to 65 years, randomly recruited according to geographical location, sex, age, and socioeconomic level.Main outcome measuresTwo 24-hour recalls were used to examine dietary intake. Breakfast consumers were stratified by tertiles of Nutrient-Rich Foods Index 9.3 (NRF9.3) to assess the overall diet quality of individuals. Nutrient intake at breakfast of those in the upper tertile of NRF9.3 pooled for the 8 countries was used as a reference for the development of recommendations for LA adolescents and adults.Statistical analysesComparison of food and nutrient intake of breakfast across NRF9.3 tertiles were analyzed using the Kruskal-Wallis rank sum test.ResultsOverall breakfast was an important contributor to protein, carbohydrate, and B vitamin intakes but also to added sugar and total and saturated fat intakes relative to daily intakes. Individuals in the upper NRF9.3 tertile had higher intake of key micronutrients such as calcium and potassium at breakfast compared with other tertiles. White breads/rolls/tortillas were the most consumed food group (60%), followed by butter/margarine (40%) and coffee/tea without milk (34%-50%).ConclusionsBreakfast contributed to the daily intake of B vitamins, protein, and carbohydrates but also added sugar and total and saturated fat intakes for all countries. The proposed recommendations support the nutrient density of existing highest-quality breakfast in the LA population while addressing concerns about nutrients to be encouraged or reduced. 相似文献
5.
6.
7.
Twenty-eight members of the general public, with little nutritional knowledge and no previous commitment to dietary change, completed 7-day-weighed dietary diaries. They then attempted to change their diets, where appropriate, in line with current nutritional guidelines.
The panel achieved changes in diet that were consistent with the recent recommendations but several problems arose. In particular, although fat levels were reduced, energy levels fell and fibre goals were not reached; in addition, certain of the initial vitamin and mineral intakes gave cause for concern. These results emphasize the importance of giving advice not only about foods that might be reduced in the diet, but also about food that might be used as alternatives. They also illustrate the difficulty of persuading people to make radical changes to their eating habits even when given personal advice from a nutritionist.
The panel was small and not necessarily representative, but the results illustrate the need for more dietary analysis studies. It is not enough simply to formulate appropriate guidelines from a nutritional point of view; it is also important to ensure that the public understands them and that people make sensible decisions about their diet. 相似文献
The panel achieved changes in diet that were consistent with the recent recommendations but several problems arose. In particular, although fat levels were reduced, energy levels fell and fibre goals were not reached; in addition, certain of the initial vitamin and mineral intakes gave cause for concern. These results emphasize the importance of giving advice not only about foods that might be reduced in the diet, but also about food that might be used as alternatives. They also illustrate the difficulty of persuading people to make radical changes to their eating habits even when given personal advice from a nutritionist.
The panel was small and not necessarily representative, but the results illustrate the need for more dietary analysis studies. It is not enough simply to formulate appropriate guidelines from a nutritional point of view; it is also important to ensure that the public understands them and that people make sensible decisions about their diet. 相似文献
8.
氟哌啶醇季铵盐衍生物的合成及其对冠状动脉的作用 总被引:3,自引:1,他引:2
目的 :合成氟哌啶醇季铵盐衍生物并研究其对动物冠状动脉的作用。方法 :以氟哌啶醇为原料 ,将其与卤代烃在回流的情况下进行反应而得到其季铵盐衍生物。采用猪冠状动脉条生物测定法和Langendorff灌流法研究这些衍生物对冠状动脉的作用。结果 :合成了 7个新化合物 ( 1~ 7) ,其中化合物 7量效依赖地压低KCl所致的猪冠状动脉条收缩曲线 ,阻断较大剂量所致的冠状动脉条痉挛 ,并量效依赖地拮抗脑垂体后叶素所致的离体豚鼠心脏冠脉流量减少。结论 :化合物 7显示了良好的扩张冠状动脉的作用 ,值得进一步研究 相似文献
9.
孕妇维生素营养状况与胎儿生长发育的典型相关研究 总被引:3,自引:0,他引:3
目的 对孕妇维生素营养状况与胎儿生长发育的关系进行典型相关分析。方法 以湖南省长沙市224名孕妇为调查对象,测定了不同孕龄孕妇的血清维生素水平及胎儿生长发育评价指标,并对孕妇的膳食营养素摄入、生活因素进行了调查。结果 孕妇血清维生素E水平随妊娠进展明显上升,叶酸水平则下降,在孕晚期尤为明显;典型相关分析的结果显示:孕妇的4项血清维生素水平与孕妇产前宫高、腹围、胎儿股骨长、新生儿出生体重、新生儿Apgar评分5项指标呈正相关(P<0.05),提示孕妇维生素营养状况影响胎儿骨骼、肌肉、神经等的发育;对孕妇生活因素、膳食摄入进行综合分析的结果显示它们对胎儿生长发育的影响依次为孕妇的膳食援入(决定系数R~2=49.10%)、孕妇4种血清维生素水平(R~2=29.94%)、生活因素(R~2=14.32%)。结论 孕妇维生素营养状况与胎儿生长发育密切相关。 相似文献
10.
目的:观察锌(Zn)、维生素A(VA)、维生素B2(VB2)缺乏和补充对初断乳大鼠进食量、体重的影响。方法:通过耗竭一补充方式造成初断乳大鼠的Zn、VA、VB2单独和联合缺乏模型,后强化补充相应营养素,动态检测大鼠进食量、体重的变化。结果:Zn、VA、VB2缺乏时不同程度地影响大鼠进食量、体重,以联合缺乏影响最为突出;强化补充相应营养素后,大鼠进食量、体重均得到改善,但仍达不到正常发育水平。结论:婴幼期Zn、VA、VB2缺乏或不足可影响生长发育,应充分重视婴幼儿营养。 相似文献