全文获取类型
收费全文 | 9034篇 |
免费 | 2492篇 |
国内免费 | 129篇 |
专业分类
耳鼻咽喉 | 370篇 |
儿科学 | 193篇 |
妇产科学 | 250篇 |
基础医学 | 179篇 |
口腔科学 | 152篇 |
临床医学 | 2883篇 |
内科学 | 1703篇 |
皮肤病学 | 314篇 |
神经病学 | 685篇 |
特种医学 | 324篇 |
外科学 | 1302篇 |
综合类 | 361篇 |
现状与发展 | 2篇 |
预防医学 | 1736篇 |
眼科学 | 100篇 |
药学 | 199篇 |
1篇 | |
中国医学 | 99篇 |
肿瘤学 | 802篇 |
出版年
2024年 | 61篇 |
2023年 | 410篇 |
2022年 | 115篇 |
2021年 | 254篇 |
2020年 | 486篇 |
2019年 | 164篇 |
2018年 | 559篇 |
2017年 | 600篇 |
2016年 | 616篇 |
2015年 | 713篇 |
2014年 | 711篇 |
2013年 | 1038篇 |
2012年 | 382篇 |
2011年 | 338篇 |
2010年 | 513篇 |
2009年 | 628篇 |
2008年 | 301篇 |
2007年 | 234篇 |
2006年 | 277篇 |
2005年 | 196篇 |
2004年 | 150篇 |
2003年 | 116篇 |
2002年 | 95篇 |
2001年 | 183篇 |
2000年 | 115篇 |
1999年 | 153篇 |
1998年 | 268篇 |
1997年 | 285篇 |
1996年 | 307篇 |
1995年 | 246篇 |
1994年 | 173篇 |
1993年 | 117篇 |
1992年 | 86篇 |
1991年 | 85篇 |
1990年 | 77篇 |
1989年 | 93篇 |
1988年 | 72篇 |
1987年 | 56篇 |
1986年 | 47篇 |
1985年 | 52篇 |
1984年 | 46篇 |
1983年 | 43篇 |
1982年 | 30篇 |
1981年 | 42篇 |
1980年 | 21篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 15篇 |
1976年 | 14篇 |
1975年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
目的:观察健脾疏肝降脂方治疗非酒精性脂肪肝(NAFLD)肥胖小鼠ALT、AST、FFA及光镜下病理组织学改变,并与壳脂胶囊治疗组比较,观察其疗效。方法:将72只小鼠随机分为模型组、健脾疏肝降脂方高、中、低剂量组、壳脂胶囊对照组和空白组。采用饲养高脂饲料及皮下注射5%CCl4复制NAFLD肥胖小鼠模型,分别以相应药物灌胃6周,检测血清中ALT、AST及FFA的含量,光镜下观察肝组织的脂肪变程度。结果:①各个用药组相比模型组,血清ALT、AST均降低有统计学意义(P<0.01),且中药各浓度组较壳脂胶囊组血清ALT、AST降低,差异有统计学意义(P<0.05); 中药高、中剂量组相比模型组FFA降低,比较有统计学意义(P<0.05); 但与壳脂胶囊组相比,中药各剂量组改善FFA,差异无明显统计学意义(P>0.05)。②光镜可见:各用药组光镜下病理组织改变均较模型组明显,以中、高剂量组较低剂量组小鼠肝细胞脂肪变程度减轻较明显。结论:健脾疏肝降脂方能有效降低NAFLD肥胖小鼠的肝功能、其与浓度无关; 可以降低FFA及改善光镜下肝脏的脂肪变,其有效程度与浓度有一定的关系。 相似文献
12.
13.
Mary C. Gawlicki MBA Margaret C. Reilly MPH Ana Popielnicki BA Kate Reilly MA 《Value in health》2006,9(3):199-204
INTRODUCTION: There are no measures of health-related absenteeism and presenteeism validated for use in the large and increasing US Spanish-speaking population. Before using a Spanish translation of an available English-language questionnaire, the linguistic validity of the Spanish version must be established to ensure its conceptual equivalence to the original and its cultural appropriateness. OBJECTIVE: The objective of this study was to evaluate the linguistic validity of the US Spanish version of the Work Productivity and Activity Impairment questionnaire, General Health Version (WPAI:GH). METHODS: A US Spanish translation of the US English WPAI:GH was created through a reiterative process of creating harmonized forward and back translations by independent translators. Spanish-speaking and English-speaking subjects residing in the US self-administered the WPAI:GH in their primary language and were subsequently debriefed by a bilingual (Spanish-English) interviewer. RESULTS: US Spanish subjects (N = 31) and English subjects (N = 35), stratified equally by educational level, with and without a high school degree participated in the study. The WPAI-GH item comprehension rate was 98.6% for Spanish and 99.6% for English. Response revision rates during debriefing were 1.6% for Spanish and 0.5% for English. Responses to hypothetical scenarios indicated that both language versions adequately differentiate sick time taken for health and non-health reasons and between absenteeism and presenteeism. CONCLUSION: Linguistic validity of the US Spanish translation of the WPAI:GH was established among a diverse US Spanish-speaking population, including those with minimal education. 相似文献
14.
15.
Relationships Between Arousal-Related Moods and Episodic Tension-Type Headache: A Biopsychological Study 总被引:3,自引:0,他引:3
An exploratory study was conducted examining arousal-related moods and episodic tension-type headache. Twelve subjects meeting International Headache Society criteria for episodic tension-type headache and 12 headache-free controls recorded headache activity and mood eight times daily for 14 consecutive days. Moods were measured using the Activation-Deactivation Adjective Check List, a self-report list that subjectively represents general arousal along two dimensions of Tension and Energy. Headache subjects had higher Tension levels than controls even in the absence of pain, and greater variation in this dimension as well. Within the headache group, Tension during pain-free periods was significantly lower than when experiencing headache, and was correlated with headache activity. The results were taken to support Thayer's (1989) biopsychological model of mood and arousal, and are discussed in terms of the model's heuristic value for general arousal and headache research. 相似文献
16.
犬MC1R基因多态性的研究 总被引:5,自引:0,他引:5
目的 利用PCR—RFLP和PCR—SSCP技术分别检测犬MC1R基因中两个序列T105A和R306Ter的基因多态性,为遗传育种、培育出更加优良的实验用犬奠定基础。方法 以224只犬为实验材料,对犬MC1R基因T105A片段和R306Ter片段分别进行PCR-RFLP和PCR—SSCP分析,并且分别对具有RFLP和SSCP多态性的片段进行克隆测序,找出等位基因的差异位点。结果 经对犬MClR基因的PCR-RFLP分析,发现犬MC1R基因的T105A序列具有多态性,表现为三种基因型:AA、AB和BB。通过对具有RFLP多态性的片段进行克隆测序发现MC1R基因在编码第105位氨基酸的密码子处存在由G到A的单碱基突变,该突变导致第105位氨基酸发生由精氨酸向苏氨酸的改变,此外在第207位氨基酸的密码子处还发现由A到G的单碱基突变,并产生了一个HhαI限制性内切酶位点。同时,经过犬MC1R基因的PCR—SSCP分析,发现犬MC1R基因的R306Ter序列具有多态性,表现为三种基因型:CC、CD、DD.通过对具有SSCP多态性的片段进行了克隆测序发现,MC1R基因在编码第306位氨基酸的密码子处存在一个由CGA到TGA的终止突变,而使翻译终止。结论 利用PCR—RFLP和PCR—SSCP分析技术证实犬MC1R基因具有明显的多态性。 相似文献
17.
Peter Stone MD FRNZCOG FRCOG David Cook FRNZCOG MRCOG John Hutton PhD FRNZCOG FRCOG Gordon Purdie BSc Henry Murray MD FRNZCOG MRCOG Lauren Harcourt MPP BA 《The Australian & New Zealand journal of obstetrics & gynaecology》1995,35(1):32-37
Summary: This is the first report of the largest study of blood pressure measurement in pregnancy in a New Zealand population using standardized definitions and methodology. Over 3,800 women who delivered in an 8-month period in the Wellington region were included in the study. Blood pressure measurement and the presence of oedema and proteinuria were recorded from booking until delivery and in the puerperium. Only 2.7% of women were unable to be contacted after delivery for details on outcomes. The results established normal ranges for blood pressure throughout pregnancy. The data show that Mood pressure greater than 140/90 until 35 weeks' gestation is outside 2 standard deviations at all gestations and justifies using these measurements as the definition of hypertension in pregnancy. The fall in blood pressure in the 2nd trimester was less than 1 mm Ffg per week in both the systolic and diastolic pressures. This fall was smaller than previously recorded in other studies. Gestational hypertension was the commonest blood pressure abnormality occurring in 15.2% of the population. This represented 69% of the pregnant women with a hypertensive disorder. The overall incidence of both gestational hypertension and preeclampsia was 18.5% which is higher than reported in other parts of the world. In this study obesity was significantly associated with hypertensive disorders in pregnancy. An arm circumference of >33 cm, one of the measurements of obesity, was found in 6.8% of the study population. Even after the effect of arm circumference was taken into account, hypertensive disorders were also more common in Pacific Island women. Ankle oedema was significantly associated with the development of both gestational hypertension and preeclampsia but the incidence of oedema was noted in only 11.9% of the subjects. 相似文献
18.
Michael C. Dalsing MD Melissa Kevorkian BS Beth Raper BA Craig Nixon MS Stephen G. Lalka MD Dolores F. Cikrit MD Joseph L. Unthank PhD Malcolm B. Herring MD 《Annals of vascular surgery》1989,3(2):127-133
This study evaluates the potential for endothelial seeding of a collagen-impregnated Dacron graft with or without surface modifiers (fibronectin, heparin) to attach and retain these cells during flow. Human umbilical endothelial cells were harvested, cultured, labeled with Indium111-oxine and seeded onto 30 mm X 4 mm diameter grafts. Six graft surfaces were studied: 1) a collagen-impregnated Dacron graft, HemashieldR (C); 2) C + fibronectin (C + F); 3) C + heparin (C + H); 4) C + F + H; 5) HytrelR + F (Hyt + F); and 6) Hyt + F + H. Radioactive loss determined the percentage attachment and then percentage retention of labeled inoculum after a one-hour in vitro perfusion. Scanning electron and light microscopy demonstrated the endothelium on the graft surface following perfusion. Fibronectin-coated grafts had a significantly higher percentage attachment than those without fibronectin (ANOVA, P less than 0.05). However, the percentage retention following perfusion was similar for all Dacron grafts and statistically inferior to the HytrelR grafts studied (ANOVA, P less than 0.05). SEM evaluation of the C + F + H graft surface was qualitatively the most impressive Dacron surface for seeding, yet was inferior to the HytrelR graft. We conclude that fibronectin benefits the initial attachment of endothelium to collagen-coated Dacron rivaling the HytrelR surface. Fibronectin does not improve percentage retention of the HemashieldR surface during perfusion, therefore, some of its initial benefit is lost. 相似文献
19.
Leonard A. Jason PhD Steven B. Pokorny PhD Monica Adams MPH Annie Topliff MA Courtney Harris BA Yvonne Hunt PhD 《The American journal on addictions / American Academy of Psychiatrists in Alcoholism and Addictions》2009,18(5):367-374
This study evaluated the effects of tobacco Purchase, Use and Possession (PUP) laws on student perceptions of adolescent tobacco use within towns and schools. Twenty‐four towns were randomly assigned into two conditions, the experimental condition (E PUP) involved efforts to increase both PUP law enforcement and reduce minors' access to commercial sources of tobacco, whereas the control condition (C) focused only on efforts to reduce minors' access to commercial sources of tobacco. A hierarchical linear modeling analytical approach was selected due to the multilevel data and nested design. The present study found that over time, youth in the experimental PUP condition observed less youth tobacco usage at school and in their town, and perceived lower rates of tobacco among their peers at school and among friends than youth in the control condition. The findings suggest that PUP law enforcement might be used to strengthen community norms against youth tobacco use. 相似文献
20.
Theodore Berk MD Robert F. Crochelt BA Dr. Steven R. Peikin MD 《Digestive diseases and sciences》1986,31(5):502-505
Obese Zucker rats are less responsive than their lean littermates to the effects of cholecystokinin-octapeptide on satiety and pancreatic growth and exocrine function. We hypothesized that the hyperphagia observed in obese Zucker rats may be caused by a decreased pyloric contractile response to cholecystokinin, resulting in an increased rate of gastric emptying, decreased postprandial gastric distention, and thus decreased satiety. Pyloric muscle strips from six obese Zucker rats and six lean littermates were mounted in separate tissue baths and isometric contraction was measured in response to acetylcholine and cholecystokinin-octapeptide. The dose-response curves for acetylcholine-and cholecystokinin-octapeptide-stimulated pyloric muscle contraction were similar for both the obese and the lean rats. (For cholecystokinin, D50 obese=4.0±0.6 nM, D50 lean=3.4±0.2 nM;P=0.16). We conclude that the decreased satiety response to cholecystokinin-octapeptide observed in obese Zucker rats is not secondary to a decreased pyloric responsiveness to cholecystokinin.This work was supported by NIH grant AM28303-03. 相似文献