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   895篇
  免费   72篇
  国内免费   60篇
耳鼻咽喉   3篇
儿科学   52篇
妇产科学   15篇
基础医学   171篇
口腔科学   21篇
临床医学   107篇
内科学   220篇
皮肤病学   16篇
神经病学   21篇
特种医学   98篇
外科学   58篇
综合类   19篇
预防医学   70篇
眼科学   5篇
药学   74篇
中国医学   2篇
肿瘤学   75篇
  2023年   4篇
  2022年   4篇
  2021年   7篇
  2020年   4篇
  2019年   13篇
  2018年   17篇
  2017年   11篇
  2016年   14篇
  2015年   16篇
  2014年   30篇
  2013年   32篇
  2012年   24篇
  2011年   25篇
  2010年   32篇
  2009年   32篇
  2008年   42篇
  2007年   58篇
  2006年   24篇
  2005年   27篇
  2004年   17篇
  2003年   15篇
  2002年   25篇
  2001年   16篇
  2000年   13篇
  1999年   23篇
  1998年   38篇
  1997年   44篇
  1996年   30篇
  1995年   30篇
  1994年   33篇
  1993年   27篇
  1992年   28篇
  1991年   27篇
  1990年   17篇
  1989年   27篇
  1988年   30篇
  1987年   19篇
  1986年   13篇
  1985年   16篇
  1984年   12篇
  1983年   10篇
  1982年   12篇
  1981年   13篇
  1980年   8篇
  1979年   5篇
  1978年   11篇
  1977年   17篇
  1976年   15篇
  1975年   6篇
  1970年   3篇
排序方式: 共有1027条查询结果,搜索用时 15 毫秒
71.

Background  

This article discusses the design of a study on the prevalence of health problems (both physical and mental) and the utilisation of health care services among asylum seekers and refugees in the Netherlands, including factors that may be related to their health and their utilisation of these services.  相似文献   
72.
73.
11q trisomy is associated with a recognizable pattern of multiple malformations. Review of the literature reveals the following recurrent themes common to complex and isolated 11q trisomy: mental retardation, pre- and postnatal growth retardation, hypotonia, a distinct pattern of facial features, congenital heart defects, and limb malformations. We report four patients with partial trisomy 11q, none of which arose from the common 11/22 translocation. Three of the four patients had the previously unreported finding of upper airway obstruction secondary to a malformed epiglottis. The critical region for this malformation appears to be 11q21-23.2.  相似文献   
74.
OBJECTIVE: To determine the relationship of hypolipidemia to cytokine concentrations and clinical outcomes in critically ill surgical patients. DESIGN: Consecutive, prospective case series. SETTING: Surgical intensive care unit of an urban university hospital. PATIENTS: Subjects were 111 patients with a variety of critical illnesses, for whom serum lipid, lipoprotein, and cytokine concentrations were determined within 24 hrs of admission to a surgical intensive care unit. Controls were 32 healthy men and women for whom serum lipid, lipoprotein, and cytokine concentrations were determined. INTERVENTIONS: Blood samples were drawn on admission to the intensive care unit. Predetermined clinical outcomes including death, infection subsequent to intensive care unit admission, length of intensive care unit stay, and magnitude of organ dysfunction were monitored prospectively. MEASUREMENTS AND MAIN RESULTS: Measurements included total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, apolipoproteins A-I and B, phospholipid, triglyceride, interleukin-6, interleukin-10, soluble interleukin-2 receptor, tumor necrosis factor-alpha, and soluble tumor necrosis factor receptors p55 and p75. Mean serum lipid concentrations were extremely low: total cholesterol, 127 +/- 52 mg/dL; low-density lipoprotein cholesterol, 75 +/- 41 mg/dL; high-density lipoprotein cholesterol, 29 +/- 15 mg/dL. Total, low-density lipoprotein, and high-density lipoprotein cholesterol concentrations and apolipoprotein concentrations inversely correlated with interleukin-6, soluble interleukin-2 receptor, and interleukin-10 concentrations, whereas the triglyceride concentration correlated positively with tumor necrosis factor soluble receptors p55 and p75. Clinical outcomes were related to whether the admission cholesterol concentration was above (n = 56) or below (n = 55) the median concentration of 120 mg/dL. Each of the clinical end points occurred between 1.9- and 3.5-fold more frequently in the very low cholesterol (<120 mg/dL) group. Nine patients (8%) died during the hospitalization. Seven of the nine patients who died had total cholesterol concentrations below the median concentration of 120 mg/dL. CONCLUSIONS: Low cholesterol and lipoprotein concentrations found in critically ill surgical patients correlate with interleukin-6, soluble interleukin-2 receptor, and interleukin-10 concentrations and predict clinical outcomes.  相似文献   
75.
76.
77.
杜晓川  贾红梅  莫显斌 《医学争鸣》1999,20(9):S046-S046
1 病例报告 男,7岁.因双下肢不等长,右膝及右踝关节骨性肿大就诊.无明显外伤史,亦无红、肿、热、痛病史.查体:发育正常,营养良好.双下肢不等长,左60cm,右64cm,有跛行.右膝及右踝内侧肿大,肤色正常,关节活动无异常.X线:右侧半身诸关节(肩、肘、腕、髋、膝、踝)骨骺及干骺发育均较左侧增大,肢体较长,骨骺出现亦较对侧提早.如右尺骨茎突骨骺较左侧提早出现(图1).右肘关节肱骨小头骨骺较左侧增大(图2).右髋臼发育浅平,边缘毛糙,右股骨头骨骺较左侧明显增大,其距泪滴之距离较左侧大1.0cm,呈…  相似文献   
78.
目的:分析跟骨定量超声骨质测量中各参数与骨密度及形态计量学指标的相关性。方法:选择2004-01/2005-12广州市第六人民医院和中山大学三院骨科小腿以上截肢患者38例,将其跟骨定量超声测定的超声振幅衰减平均值与健康青年人骨峰值进行比较,>-2.5 SD者为骨量正常组(12例),<-2.5 SD者为骨质疏松组(26例)。分别进行跟骨定量超声、双能X线骨密度测量仪及骨形态计量学测量,应用直线相关分析法分析跟骨定量超声测定中各参数与骨密度及骨组织形态计量学各指标的相关性。结果:38例全部进入结果分析。①骨质疏松组跟骨超声振幅衰减平均值和骨硬度指数值均小于骨量正常组(P<0.01)。②骨量正常组跟骨骨密度值显著高于骨质疏松组[(352±16),(233±14)mg/cm2,P<0.01]。③骨量正常组跟骨平均骨小梁间距或弥散度低于骨质疏松组而松质骨体积高于骨质疏松组(P<0.05)。④超声振幅衰减平均值和骨硬度指数与骨密度呈直线正相关(r=0.814,0.326,P<0.01,0.05)。⑤超声传播速度与骨小梁游离末端、平均骨小梁间距呈直线负相关(r=-0.688,-0.712,P<0.01),与小梁间连点数、松质骨体积呈直线正相关(r=0.672,0.794,P<0.01);骨硬度指数与平均骨小梁间距呈直线负相关(r=-0.358,P<0.05),与松质骨体积呈直线正相关(r=0.513,P<0.01)。结论:跟骨定量超声测量中,超声振幅衰减平均值能较好地反映骨的密度,超声传播速度能较好地反映骨的质量,而骨硬度指数能较综合地反映骨强度的改变。  相似文献   
79.
Considerable controversy exists as to the appropriate dosing of heparin for PTCA. We retrospectively reviewed records of 335 patients undergoing PTCA to determine: 1) the effects of correcting for weight and body surface area (BSA) on the heparin dose-response distribution; and 2) the average dose of heparin (standard, weight-based, and BSA-based) required to achieve an activated clotting time (ACT) of 300 seconds. For each patient, height, weight, BSA, baseline ACT (HemoTec), bolus heparin dose, and post-heparin ACT were recorded and the heparin response calculated. There were no significant differences in the distributions of standard (SD =.017 +/- 006 sec/U, 34% of mean), weight-based (SD = 1.41 +/- 0.46 sec/U/kg, 33% of mean), and BSA-based (SD = 0.033 +/- 0.011 sec/U/m2, 32% of mean) heparin response. There were slight, but significant correlations between heparin response and weight (r = 0.37) and heparin response and BSA (r = 0.36). The estimated doses of heparin to achieve a HemoTec ACT of 300 seconds were 10,650 +/- 1270 U, 130 +/- 15 U/kg, and 5390 +/- 640 U/m2. CONCLUSIONS: There are slight but significant correlations between heparin response and both weight and BSA. The distributions of weight- and BSA-corrected heparin response are similar to that of standard heparin dosing. Thus, weight adjusted heparin dosing would not appear to be likely to provide a more reliable ACT response to bolus doses of heparin.  相似文献   
80.

Background

Adequate vitamin D concentrations during pregnancy are necessary to neonatal calcium homeostasis, bone maturation and mineralization. The aim of study is to evaluate serum vitamin D concentrations in mothers and their newborns and effect of vitamin D deficiency on pregnancy outcomes.

Methods

552 pregnant women were recruited from Tehran University educating hospitals in the winter of 2002. Maternal and cord blood samples were taken at delivery. The serum was assayed for 25-hydroxyvitamin D3, calcium, phosphorus and parathyroid hormone.

Results

The prevalence of vitamin D deficiency in maternal and cord blood samples were 66.8% and 93.3%, respectively (<35 nmol/l). There was significant correlation between maternal and cord blood serum concentrations of vitamin D. In mothers with vitamin D deficiency, cord blood vitamin D concentrations was lower than those from normal mothers (P = .001). Also, a significant direct correlation was seen between maternal vitamin D intake and weight gain during pregnancy.

Conclusion

Consideration to adequate calcium and vitamin D intake during pregnancy is essential. Furthermore, we think it is necessary to reconsider the recommendation for vitamin D supplementation for women during pregnancy.  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