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   1369篇
  免费   103篇
  国内免费   2篇
耳鼻咽喉   13篇
儿科学   80篇
妇产科学   43篇
基础医学   247篇
口腔科学   39篇
临床医学   100篇
内科学   256篇
皮肤病学   18篇
神经病学   90篇
特种医学   24篇
外科学   102篇
综合类   18篇
一般理论   2篇
预防医学   69篇
眼科学   137篇
药学   76篇
中国医学   8篇
肿瘤学   152篇
  2024年   3篇
  2023年   10篇
  2022年   41篇
  2021年   69篇
  2020年   53篇
  2019年   51篇
  2018年   65篇
  2017年   40篇
  2016年   38篇
  2015年   48篇
  2014年   62篇
  2013年   71篇
  2012年   114篇
  2011年   109篇
  2010年   66篇
  2009年   44篇
  2008年   81篇
  2007年   61篇
  2006年   62篇
  2005年   76篇
  2004年   55篇
  2003年   44篇
  2002年   52篇
  2001年   21篇
  2000年   16篇
  1999年   14篇
  1998年   8篇
  1997年   6篇
  1996年   4篇
  1995年   8篇
  1994年   3篇
  1993年   3篇
  1992年   7篇
  1991年   3篇
  1990年   8篇
  1989年   8篇
  1988年   3篇
  1987年   2篇
  1986年   7篇
  1985年   10篇
  1984年   5篇
  1983年   4篇
  1982年   2篇
  1981年   5篇
  1980年   2篇
  1979年   2篇
  1976年   4篇
  1975年   1篇
  1974年   1篇
  1972年   1篇
排序方式: 共有1474条查询结果,搜索用时 54 毫秒
71.
Surgery alters the body’s homeostatic balance and defense mechanisms. In adults transient postoperative cellular and humoral immunosuppression after different degrees of operative stress has been reported. In children the immunologic consequences of operations are not elaborated. This study investigates the effect of minor and major surgery on early nonspecific immune response in terms of neutrophil counts and function. Forty-three children undergoing minor and major elective procedures were studied. Blood samples were collected before, immediately after, and 72 h after surgery. Total white cell count, differential neutrophil count, and neutrophil phagocytic function were studied using nitroblue tetrazolium test. Children were divided into two groups—group 1 underwent minor surgery and group 2 major surgery. In group 1 there was a significant drop in total counts after surgery, but in group 2 total counts were not affected. In both groups, the percentage of neutrophils increased immediately after surgery but fell to near or less than preoperative levels 72 h after surgery. However, the assessment of neutrophil functions by nitroblue tetrazolium test in both unstimulated and stimulated forms revealed it to be unchanged in group 1. In group 2 the unstimulated neutrophil function was elevated 72 h after surgery, whereas stimulated function was elevated immediately after surgery. Minor surgery does not alter the early nonspecific immune response. However, major surgery seems to induce a transient increase in neutrophil phagocytic activity.  相似文献   
72.
Polymorphisms of three different dopaminergic genes, dopamine D2 receptor (DRD2), dopamine β-hydroxylase (DβH), and dopamine transporter (DAT1), were examined in Tourette syndrome (TS) probands, their relatives, and controls. Each gene individually showed a significant correlation with various behavioral variables in these subjects. The additive and subtractive effects of the three genes were examined by genotyping all three genes in the same set of subjects. For 9 of 20 TS associated comorbid behaviors there was a significant linear association between the degree of loading for markers of three genes and the mean behavior scores. The behavior variables showing the significant associations were, in order, attention deficit hyperactivity disorder (ADHD), stuttering, oppositional defiant, tics, conduct, obsessive-compulsive, mania, alcohol abuse, and general anxiety-behaviors that constitute the most overt clinical aspects of TS. For 16 of the 20 behavior scores there was a linear progressive decrease in the mean score with progressively lesser loading for the three gene markers. These results suggest that TS, ADHD, stuttering, oppositional defiant and conduct disorder, and other behaviors associated with TS, are polygenic, due in part to these three dopaminergic genes, and that the genetics of other polygenic psychiatric disorders may be deciphered using this technique. © 1996 Wiley-Liss, Inc.  相似文献   
73.
Background/ObjectivesTo characterise the patterns of presentation and diagnostic frequencies in Hospital Emergency Eye Care Services (HEECS) across 13 hospitals in England.MethodsRetrospective, cross-sectional, observational multi-centre (n = 13) study to assess HEECS attendances over a 28-day study period. Data derived included: number of consecutive attendances, patient demographics and diagnoses. Age and gender variations, the impact of day of the week on attendance patterns, diagnostic frequencies and estimates of the annual incidence and attendance rates were evaluated.ResultsA total of 17,667 patient (mean ± standard deviation age = 49.6 ± 21.8 years) attendances were identified with an estimated HEECS annual new attendance rate of 31.0 per 1,000 population. Significantly more females (53%) than males (47%) attended HEECS (p < 0.001). Female attendances were 13% higher in those ≥50 years of age. Weekends were associated with a significant reduction in attendances compared to weekdays (χ2 = 6.94, p < 0.001). Among weekdays, Mondays and Fridays were associated with significantly higher attendances compared with midweek (χ2 = 2.20, p = 0.032). Presenting pathologies involving the external eye, cornea and conjunctiva accounted for 28.6% of the caseload.ConclusionThis is the largest multicentre study assessing attendance patterns in HEECS in England. We have, for the first time, observed a “weekend effect” in relation to attendance to HEECS. Differences in health-seeking behaviour and lack of awareness of HEECS weekend services may be partly attributed to the differences observed. Our findings, along with the type of presentations, have the potential to guide commissioners with future planning of HEECS.Subject terms: Epidemiology, Epidemiology  相似文献   
74.
Indian Journal of Pediatrics - Youth and adolescents are the priority population to target the interventions as risky behaviors persist and they contribute to almost half of the new Human...  相似文献   
75.
76.
77.
78.
Purpose:To compare multicolor imaging (MCI) with Optos color fundus photography (OCFP) for the evaluation of morphology and extent of preretinal membranes in diabetic tractional retinal detachments (TRD).Methods:In this retrospective study, 30 eyes with diabetic TRDs were imaged using the MCI feature of the Heidelberg Spectralis Spectral-domain optical coherence tomography (SD-OCT) and color photo using the Optos Daytona ultra-widefield fundus camera. Two investigators independently graded and determined the agreeability between the two modalities with respect to the extent of the TRD and preretinal membranes on the SD-OCT B-scan images.Results:The MCI provided better visualization of the attachments and traction points of the posterior hyaloid face and preretinal membranes and is comparable to the SD-OCT B-scan images. The inter-rater agreeability rates for OCFP had a Kappa (κ) value of 0.37, while the MCI had a κ value of 0.46. When comparing between images of different wavelengths, grading using infrared reflectance (IR) had a poor agreement (−0.04 ± 0.04) while green reflectance (GR) (0.46 ± 0.32) and blue reflectance (BR) (0.53 ± 0.19) had a moderate agreement. The composite MCI and GR images also had comparatively higher intraclass coefficient when compared to the OCFP (0.25 [−0.09–0.55]) and IR (−0.03 [−0.39–0.34]) images.Conclusion:MCI is more sensitive for determining the extent of TRDs and for the detection of secondary membranes when compared to OCFP, thus, aiding in better surgical planning.  相似文献   
79.
80.
Summary The gastric juice secretion, acid concentration and peptic activity were studied before and after pentagastrin stimulation in 10 sea level residents, first at sea level and then during 22 days sojourn at 3,500 m and in two other groups of 10 men, one of which consisted of natives of high altitude and the other of lowlanders acclimatized to high altitude. In addition, measurements of xylose excretion, energy, fat and protein utilization, along with fluid balance were made on sea level residents, referred to as sojourners, both at sea level and high altitude.The basal and maximal gastric juice volumes of the three groups at high altitude did not differ significantly. The maximal rate of acid production was lower in high altitude natives as compared to the other two groups. Peptic activity was higher in sojourners at high altitude, whereas it did not show any difference in acclimatised low landers as compared to sea level values of sojourners. There was no significant difference in D-xylose excretion in sojourners at high altitude. The food intake of sojourners was reduced at high altitude without any change in the efficiency of food utilization. There was no change in fluid balance.  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