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   1059595篇
  免费   81124篇
  国内免费   2784篇
耳鼻咽喉   13451篇
儿科学   36377篇
妇产科学   29535篇
基础医学   154094篇
口腔科学   29134篇
临床医学   97129篇
内科学   206727篇
皮肤病学   23771篇
神经病学   85212篇
特种医学   40406篇
外国民族医学   306篇
外科学   158409篇
综合类   24533篇
一般理论   455篇
预防医学   83529篇
眼科学   24196篇
药学   76214篇
  4篇
中国医学   2103篇
肿瘤学   57918篇
  2019年   8499篇
  2018年   12012篇
  2017年   9321篇
  2016年   10548篇
  2015年   11965篇
  2014年   16496篇
  2013年   24844篇
  2012年   33547篇
  2011年   35501篇
  2010年   21151篇
  2009年   19800篇
  2008年   33085篇
  2007年   35169篇
  2006年   35590篇
  2005年   33991篇
  2004年   33150篇
  2003年   31605篇
  2002年   30554篇
  2001年   47463篇
  2000年   48431篇
  1999年   40845篇
  1998年   11968篇
  1997年   10771篇
  1996年   10736篇
  1995年   10310篇
  1994年   9526篇
  1993年   8907篇
  1992年   32585篇
  1991年   31770篇
  1990年   31269篇
  1989年   30123篇
  1988年   27419篇
  1987年   27518篇
  1986年   25666篇
  1985年   24815篇
  1984年   18681篇
  1983年   15828篇
  1982年   9645篇
  1981年   8707篇
  1979年   17047篇
  1978年   12445篇
  1977年   10488篇
  1976年   9880篇
  1975年   10276篇
  1974年   12417篇
  1973年   11929篇
  1972年   10957篇
  1971年   10177篇
  1970年   9433篇
  1969年   8766篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.

Background

Early dumping is a poorly defined and incompletely understood complication after Roux-en-Y gastric (RYGB).

Objective

We performed a mixed-meal tolerance test in patients after RYGB to address the prevalence of early dumping and to gain further insight into its pathophysiology.

Setting

The study was conducted in a regional hospital in the northern part of the Netherlands.

Methods

From a random sample of patients who underwent primary RYGB between 2008 and 2011, 46 patients completed the mixed-meal tolerance test. The dumping severity score for early dumping was assessed every 30 minutes. A sum score at 30 or 60 minutes of ≥5 and an incremental score of ≥3 points were defined as indicating a high suspicion of early dumping. Blood samples were collected at baseline, every 10 minutes during the first half hour, and at 60 minutes after the start.

Results

The prevalence of a high suspicion of early dumping was 26%. No differences were seen for absolute hematocrit value, inactive glucagon-like peptide-1, and vasoactive intestinal peptide between patients with or without early dumping. Patients at high suspicion of early dumping had higher levels of active glucagon-like peptide-1 and peptide YY.

Conclusion

The prevalence of complaints at high suspicion of early dumping in a random population of patients after RYGB is 26% in response to a mixed-meal tolerance test. Postprandial increases in both glucagon-like peptide-1 and peptide YY are associated with symptoms of early dumping, suggesting gut L-cell overactivity in this syndrome.  相似文献   
92.
The recent death of our colleague and friend Professor Sir Michael Rutter has quite rightly been greeted by an outpouring of gratitude and respect from distinguished commentators across the globe working in diverse fields of the basic, social and clinical sciences as well as from clinicians and policy makers. These have without exception highlighted his seminal role as a pioneer, perhaps The Pioneer, of the application of the scientific method to the study of child and adolescent mental health and disorder – the father of evidence-based Child Psychiatry and the most influential voice in the new field of Developmental Psychopathology (Stevenson, 2022). In this editorial, we will attempt to build on these commentaries. We will parse Mike’s scientific contributions to our field, in order to identify the personal characteristics and intellectual modus operandi that made him such a uniquely important figure, whose influence will resonate through the many fields he influenced for decades to come. We will also attempt something of a reframing of that contribution. Our thesis being that, although he never agitated for it politically or even stated it as a goal explicitly, Mike’s work was motivated by a desire for social reform and created the scientific catalyst for such reform to occur.  相似文献   
93.
Objective: Longitudinal data on cardiometabolic effects of egg intake during adolescence are lacking. The current analyses aim to evaluate the impact of usual adolescent egg consumption on lipid levels, fasting glucose, and insulin resistance during late adolescence (age 17–20?years).

Methods: Data from 1392 girls, aged 9 to 10 at baseline and followed for 10?years, in the National Heart, Lung, and Blood Institute’s National Growth and Health Study were used to examine the association between usual egg intake alone and in combination with other healthy lifestyle factors and late adolescent lipid levels, fasting glucose, and insulin resistance, measured as homeostasis model assessment of insulin resistance (HOMA-IR). Diet was assessed using 3-day food records during eight examination cycles. Girls were classified according to usual weekly egg intake, ages 9–17?years:?<1 egg/wk (n?=?361), 1 to <3 eggs/wk (n?=?703), and ≥3 eggs/wk (n?=?328). Analysis of covariance modeling was used to control for confounding by other behavioral and biological risk factors.

Results: Girls with low, moderate, and high egg intakes had adjusted low-density lipoprotein cholesterol levels of 99.7, 98.8, and 95.5 mg/dL, respectively (p?=?0.0778). In combination with higher intakes of fiber, dairy, or fruits and vegetables, these beneficial effects were stronger and statistically significant. There was no evidence that ≥3 eggs/wk had an adverse effect on lipids, glucose, or HOMA-IR. More active girls who consumed ≥3 eggs/wk had the lowest levels of insulin resistance.

Conclusion: These results suggest that eggs may be included as part of a healthy adolescent diet without adverse effects on glucose, lipid levels, or insulin resistance.  相似文献   

94.

Objective

Low psoas muscle area is shown to be an indicator for worse postoperative outcome in patients undergoing vascular surgical. Additionally, it has been associated with longer durations of hospital stay in patients with cancer who undergo surgery and subsequently greater health care costs in Europe and the United States. We sought to evaluate this effect on hospital expenditure for patients undergoing vascular repair in a health care system with universal access.

Methods

Skeletal muscle mass was assessed on preoperative abdominal computed tomography scans of patients undergoing open aortic aneurysm repair in a retrospective fashion. The skeletal muscle index (SMI) was used to define low muscle mass. Health care costs were obtained for all patients and the relationship between a low SMI and higher costs was explored using linear regression and cross-sectional analysis.

Results

We included 156 patients (81.5% male) with a median age of 72 years undergoing elective surgery for infrarenal abdominal aortic aneurysm in this analysis. The median SMI for patients with low skeletal muscle mass was 53.21 cm2/kg and for patients without, 70.07 cm2/kg. Hospital duration of stay was 2 days longer in patients with low skeletal muscle mass as compared with patients with normal (14 days vs 11 days; P = .001), as was duration of intensive care stay (3 days vs 1 day; P = .01). The median overall hospital costs were €10,460 higher for patients with a low SMI as compared with patients with a normal physical constitution (€53,739 [interquartile range, €45,007-€62,471] vs €43,279 [interquartile range, €39,509-€47,049]; P = .001). After confounder adjustment, a low SMI was associated with a 14.68% cost increase in overall hospital costs, for a cost increase of €6521.

Conclusions

Low skeletal muscle mass is independently associated with higher hospital as well as intensive care costs in patients undergoing elective aortic aneurysm repair. Strategies to reduce this risk factor are warranted for these patients.  相似文献   
95.

Objective

To systematically review literature on uptake and timeliness of diphtheria-tetanus-pertussis, measles-mumps-rubella, and/or polio-containing vaccines in infants who were born preterm, with a low birth weight, and/or with chronic health conditions that were diagnosed within the first 6?months of life.

Methods

Using a standardized search strategy developed by a medical librarian, records were extracted from MEDLINE, Embase, Database of Abstracts of Reviews of Effects, and CINAHL up to May 8, 2018.

Results

Out of the 1997 records that were screened, we identified 21 studies that met inclusion criteria. Eleven studies assessed vaccine coverage and/or timeliness in preterm infants, 6 in low birth weight infants, and 7 in children with chronic health conditions. Estimates of coverage in these populations were highly variable, ranging from 40% to 100% across the vaccines and population groups.

Conclusions

There is a lack of studies reporting coverage and timeliness of routine immunizations in special populations of children.

Policy implications

Our review suggests a need for improved surveillance of immunization status in special populations of infants, as well as a need for standardization of reporting practices.  相似文献   
96.
PurposeTo examine what proportion of caregivers, if given a choice, would choose medical versus surgical treatment of appendicitis and what factors would be important in their decision.MethodsA survey was devised and given to the caregivers of children presenting to the pediatrician for a routine visit in community and academic pediatric clinics. The survey presented a summary of outcomes after medical (non-operative) and surgical treatment of uncomplicated appendicitis. Participants were then asked to choose medical versus surgical treatment if their child were to develop appendicitis. They were also asked to rate the importance of certain factors in their decision ? 1 being “not important” and 5 being “very important”.ResultsFour hundred surveys were distributed with an 86.2% (345/400) response rate. Six percent (21/342) of respondents reported a history of appendicitis and 49.4% (168/340) reported having known someone who had appendicitis. The majority of respondents, 85.3% (284/333), were mothers. A minority of respondents, 41.7% (95% CI: 36.7, 47.0), chose medical treatment over surgery for appendicitis. There was no statistical difference in the proportion of mothers (41.6%) versus fathers who chose medical treatment (41.3%). Caregivers who chose medical treatment were more likely to rate time in hospital (p = .008) and time out of school (p = 05) as important in decision making when compared with those who chose surgery. Those who chose surgical treatment were more likely to rate risk of recurrent appendicitis (p < .001) as important to decision making. In the multivariate analysis, those who rated time in hospital as very important had more than twice the odds of choosing medical therapy (OR 2.20, p = 0.02) when compared with those who rated it as less important. Not knowing someone who has had appendicitis was significantly associated with choosing medical therapy when compared with those who do know someone who has had appendicitis, OR 2.3, p = .002. Rating pain as very important was also significantly associated with choosing medical therapy, when compared to those rating pain 1–3, OR 3.38, p = .03.ConclusionsIn this survey of caregivers of children presenting for routine care, 41.7% would choose medical, or non-operative, therapy for their children with acute appendicitis. The risk of recurrence, time in hospital, and time out of school, pain, and knowing someone who has had appendicitis were all important factors that families may consider when making a decision. These data may be useful for surgeons counseling patients on which treatment to pursue.  相似文献   
97.
98.
99.
Abstract

The study examines Parental Feeding Practices (PFP) in relation to adherence to the Mediterranean Diet (MD) and children’s weight status. It’s a cross-sectional study of 402 parents (68.4% mothers), with children aged 2–12 years. Parents completed the Comprehensive Parental Feeding Questionnaire and the Mediterranean Diet Quality Index for children and adolescents (KIDMED), evaluating children’s adherence to the MD. Logistic regression showed that in children aged 2–<6 years, “emotion regulation/food as reward” and “pressure” decrease MD adherence (OR?=?0.186, p?<?0.0001 and OR?=?0.496, p?=?0.004), and “monitoring” decrease excess body weight (OR?=?0.284, p?=?0.009). In older children (6–12 years), “healthy eating guidance” and “monitoring” increase MD adherence (OR?=?3.262, p?=?0.001 and OR?=?3.147, p?<?0.0001), “child control” decreases MD adherence (OR?=?0.587, p?=?0.049), “pressure” decrease excess body weight (OR?=?0.495, p?<?0.0001) and “restriction” increase excess body weight (OR?=?1.784, p?=?0.015). “Healthy eating guidance” and “monitoring” seem to be the best PFP employed, in terms of children’s MD adherence and weight status.  相似文献   
100.
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