首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1590篇
  免费   77篇
耳鼻咽喉   2篇
儿科学   43篇
妇产科学   34篇
基础医学   207篇
口腔科学   11篇
临床医学   295篇
内科学   235篇
皮肤病学   26篇
神经病学   138篇
特种医学   22篇
外科学   139篇
综合类   30篇
一般理论   1篇
预防医学   321篇
眼科学   7篇
药学   94篇
肿瘤学   62篇
  2024年   3篇
  2023年   17篇
  2022年   18篇
  2021年   51篇
  2020年   25篇
  2019年   43篇
  2018年   47篇
  2017年   38篇
  2016年   33篇
  2015年   34篇
  2014年   35篇
  2013年   79篇
  2012年   141篇
  2011年   156篇
  2010年   57篇
  2009年   55篇
  2008年   111篇
  2007年   132篇
  2006年   110篇
  2005年   108篇
  2004年   71篇
  2003年   85篇
  2002年   57篇
  2001年   10篇
  2000年   14篇
  1999年   17篇
  1998年   13篇
  1997年   14篇
  1996年   6篇
  1995年   9篇
  1994年   10篇
  1993年   6篇
  1992年   7篇
  1991年   3篇
  1990年   5篇
  1989年   3篇
  1988年   2篇
  1987年   2篇
  1986年   4篇
  1984年   3篇
  1983年   4篇
  1982年   3篇
  1980年   3篇
  1978年   7篇
  1976年   2篇
  1973年   2篇
  1972年   2篇
  1948年   1篇
  1935年   1篇
  1917年   1篇
排序方式: 共有1667条查询结果,搜索用时 15 毫秒
101.
This paper presents a case study of the efforts by one state (Arizona) to increase Children's Health Insurance Program enrollment through outreach projects funded by private foundations. Barriers to enrollment include the organization of the Children's health Insurance Program and perceptions of parents. The most successful outreach either involves intensive personal contact or is connected with a health care provider agency. The paper concludes by discussing how the barriers and successful outreach strategies in Arizona can be generalized to other states and can inform Children's Health Insurance Program outreach broadly.  相似文献   
102.
Hepatocyte proliferation represents an important part of tissue repair. In these studies, TNF receptor 1 (TNFR1) knockout mice were used to analyze the role of TNF-alpha in hepatocyte proliferation during acetaminophen-induced hepatotoxicity. Treatment of wild-type (WT) mice with acetaminophen (300 mg/kg) resulted in centrilobular hepatic necrosis. This was associated with proliferation of hepatocytes surrounding the damaged areas, which was evident at 24 h. The cell cycle regulatory proteins, cyclin D1 and cyclin A, were also up regulated in hepatocytes. In contrast, in TNFR1-/- mice, which exhibit exaggerated acetaminophen hepatotoxicity, hepatocyte proliferation, and expression of cyclin D1 and cyclin A, as well as the cyclin dependent kinases, Cdk4 and Cdk2, were reduced. The cyclin-dependent kinase inhibitor p21 was also induced in the liver following acetaminophen administration. This was greater in TNFR1-/- mice compared to WT mice. To investigate mechanisms mediating the reduced hepatic proliferative response of TNFR1-/- mice, we analyzed phosphatidyl inositol-3-kinase (PI-3K) signaling. In both WT and TNFR1-/- mice, acetaminophen caused a rapid increase in total PI-3K within 3 h. Acetaminophen also increased phosphorylated PI-3K, but this was delayed 6-12 h in TNFR1-/- mice. Expression of Akt, a downstream target of PI-3K, was increased in both WT and TNFR1-/- mice in response to acetaminophen. However, the increase was greater in WT mice. Acetaminophen-induced expression of phosphorylated STAT3, a key regulator of cytokine-induced hepatocyte proliferation, was also delayed in TNFR1-/- mice relative to WT. These data suggest that TNF-alpha signaling through TNFR1 is important in regulating hepatocyte proliferation following acetaminophen-induced tissue injury. Delayed cytokine signaling may account for reduced hepatocyte proliferation and contribute to exaggerated acetaminophen-induced hepatotoxicity in TNFR1-/- mice.  相似文献   
103.
Immunization with amyloid-beta (Abeta) peptide in mouse models of Alzheimer's disease has been reported to decrease cerebral Abeta levels and improve behavioral deficits. Several mechanisms have been proposed, including antibody-induced phagocytosis of Abeta by cerebral microglia and increased efflux of Abeta from the brain to the periphery. The latter mechanism was suggested in mice undergoing acute, passive transfer of an Abeta monoclonal antibody. Here, PSAPP transgenic mice were actively immunized by a single intraperitoneal injection of synthetic Abeta followed by chronic intranasal administration of Abeta with the mucosal adjuvant, Escherichia coli heat-labile enterotoxin, LT, twice weekly for 8 weeks. Serum from Abeta-immunized mice had an average of 240 microg/ml of anti-Abeta-specific antibodies; these antibodies had epitope(s) within Abeta1-15 and were of immunoglobulin (Ig) isotypes IgG2b, IgG2a, and IgG1. Immunization led to a 75% decrease in plaque number (P < 0.0001) and a 58% decrease in Abetax-42 levels (P < 0.026) in brain, and gliosis and neuritic dystrophy were diminished. No pathological effects of the immunization were observed in kidney, spleen, or snout. Serum Abeta levels increased 28-fold in immunized mice (53.06 ng/ml) compared to controls (1.87 ng/ml). Most of the Abeta in the serum of the immunized mice was bound to antibodies. We conclude that following active immunization, anti-Abeta antibodies sequester serum Abeta and may increase central nervous system to serum Abeta clearance.  相似文献   
104.
OBJECTIVE: The use of diets with low glycemic index (GI) in the management of diabetes is controversial, with contrasting recommendations around the world. We performed a meta-analysis of randomized controlled trials to determine whether low-GI diets, compared with conventional or high-GI diets, improved overall glycemic control in individuals with diabetes, as assessed by reduced HbA(1c) or fructosamine levels. RESEARCH DESIGN AND METHODS: Literature searches identified 14 studies, comprising 356 subjects, that met strict inclusion criteria. All were randomized crossover or parallel experimental design of 12 days' to 12 months' duration (mean 10 weeks) with modification of at least two meals per day. Only 10 studies documented differences in postprandial glycemia on the two types of diet. RESULTS: Low-GI diets reduced HbA(1c) by 0.43% points (CI 0.72-0.13) over and above that produced by high-GI diets. Taking both HbA(1c) and fructosamine data together and adjusting for baseline differences, glycated proteins were reduced 7.4% (8.8-6.0) more on the low-GI diet than on the high-GI diet. This result was stable and changed little if the data were unadjusted for baseline levels or excluded studies of short duration. Systematically taking out each study from the meta-analysis did not change the CIs. CONCLUSIONS: Choosing low-GI foods in place of conventional or high-GI foods has a small but clinically useful effect on medium-term glycemic control in patients with diabetes. The incremental benefit is similar to that offered by pharmacological agents that also target postprandial hyperglycemia.  相似文献   
105.
106.
BACKGROUND: The practicality of diets with a low glycemic index (GI) is controversial. Theoretically, low-GI diets may limit food choice and increase dietary fat intake, but there is little objective evidence to support such a theory. OBJECTIVE: The objective was to determine the effect of low-GI dietary advice on dietary quality and food choice in children with diabetes. DESIGN: Children aged 8-13 y with type 1 diabetes (n = 104) were recruited to a prospective, randomized study comparing the effects of traditional carbohydrate-exchange dietary advice (CHOx) with those of more flexible low-GI dietary advice (LowGI). We determined the effect on long-term macronutrient intake and food choice with the use of 3-d food diaries. RESULTS: There were no differences in reported macronutrient intakes during any of the recording periods. After 12 mo, intakes of dietary fat (33.5 +/- 5.6% and 34.2 +/- 6.7% of energy, P = 0.65), carbohydrate (48.8 +/- 5.4% and 48.6 +/- 6.5% of energy, P = 0.86), protein (17.6 +/- 2.5% and 17.3 +/- 3.7% of energy, P = 0.61), total sugars, and fiber did not differ significantly between the CHOx and LowGI groups, respectively. The average number of different carbohydrate food choices per day also did not differ significantly. Subjects in the lowest-GI quartile consumed less carbohydrate as potato and white bread, but more carbohydrate as dairy-based foods and whole-grain breads than did subjects in the highest-GI quartile. CONCLUSION: Children with diabetes who receive low-GI dietary advice do not report more limited food choices or a diet with worse macronutrient composition than do children who consume a traditional carbohydrate-exchange diet.  相似文献   
107.
Inclusion of fat reduces the glycemic response to a carbohydate meal, although the effect of different types of fat on glycemic, insulinemic and satiety responses is unclear. Ten healthy men received 50-g carbohydrate portions of mashed potato with isoenergetic amounts of butter (saturated fatty acid), Sunola oil (monounsaturated fatty acid) or sunflower oil (PUFA) and two 50-g glucose loads on separate days. Capillary blood was collected at regular intervals for 2 h. Satiety ratings were assessed by use of a rating scale. The glycemic index (GI), insulin index (II) and satiety index (SI) scores were calculated. Energy intakes from a meal consumed ad libitum at 2 h and for the remainder of the day were quantified. The GI values ranged from 68 +/- 8 to 74 +/- 10 and the II values ranged from 113 +/- 10 to 122 +/- 17, but there was no effect of fat type. SI scores and subsequent energy intake did not differ among the test meals. Substitution of unsaturated fats for saturated fatty acids had no acute benefits on postprandial glycemia, insulin demand or short-term satiety in young men.  相似文献   
108.
109.
110.
Complementary and alternative medicine (CAM) is a group of diverse medical and healthcare systems, therapies, and products that are not presently considered part of conventional medicine. This article provides an up-to-date review of the efficacy of selected CAM modalities in the management of chronic pain. Findings are presented according to the classification system developed by the National Institutes of Health National Center for Complementary and Alternative Medicine (formerly Office of Alternative Medicine) and are grouped into four domains: biologically based medicine, energy medicine, manipulative and body-based medicine, and mind-body medicine. Homeopathy and acupuncture are discussed separately as "whole or professionalized CAM practices." Based on the guidelines of the Clinical Psychology Division of the American Psychological Association, findings indicate that some CAM modalities have a solid track record of efficacy, whereas others are promising but require additional research. The article concludes with recommendations to pain practitioners.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号