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   1177篇
  免费   72篇
  国内免费   11篇
耳鼻咽喉   2篇
儿科学   125篇
妇产科学   17篇
基础医学   102篇
口腔科学   37篇
临床医学   184篇
内科学   249篇
皮肤病学   16篇
神经病学   59篇
特种医学   219篇
外科学   93篇
综合类   39篇
预防医学   46篇
眼科学   9篇
药学   31篇
  1篇
肿瘤学   31篇
  2021年   3篇
  2020年   10篇
  2019年   13篇
  2018年   12篇
  2017年   14篇
  2016年   9篇
  2015年   23篇
  2014年   21篇
  2013年   21篇
  2012年   18篇
  2011年   19篇
  2010年   40篇
  2009年   45篇
  2008年   32篇
  2007年   14篇
  2006年   19篇
  2005年   16篇
  2004年   21篇
  2003年   17篇
  2002年   26篇
  2001年   21篇
  2000年   12篇
  1999年   22篇
  1998年   86篇
  1997年   87篇
  1996年   91篇
  1995年   60篇
  1994年   55篇
  1993年   48篇
  1992年   20篇
  1991年   23篇
  1990年   19篇
  1989年   43篇
  1988年   38篇
  1987年   42篇
  1986年   22篇
  1985年   32篇
  1984年   23篇
  1983年   20篇
  1982年   19篇
  1981年   20篇
  1980年   9篇
  1979年   5篇
  1978年   6篇
  1977年   8篇
  1976年   10篇
  1975年   8篇
  1971年   3篇
  1969年   3篇
  1966年   2篇
排序方式: 共有1260条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
Accurate pregnancy dating is vital to obstetric management. However, first trimester fetal charts commonly used in Australia rely on data reported more than three decades ago. This study reports first trimester dating and growth charts for crown‐rump length between 5 and 14 weeks of gestation and biparietal diameter between 9 and 14 weeks of gestation on an Australia population using modern real‐time ultrasound equipment. All consenting eligible women attending a large Sydney clinic for first trimester ultrasound between March 2005 and December 2006 were recruited. Measurements were carried out to Australasian Society for Ultrasound in Medicine standard protocols. Statistical analyses were undertaken using polynomial regression models and thorough diagnostic checks made. Overall 396 eligible women consented to the study, with 268 between 9 and 14 weeks of gestation. The average participant age was 34 years (range 22–45 years), 371 and all yielded valid biometry measurements. Equations, means and 90% reference intervals for crown‐rump length measurements and biparietal diameter measurements were derived using polynomial regression models. Thorough residual and diagnostic checks were made. Once validated by others, we believe they will warrant consideration for use by Australasian Society for Ultrasound in Medicine.  相似文献   
65.
Two patients aged 11 and four years, were accidentally given a 10-fold overdose of intrathecal methotrexate while being treated for malignant disease. Neither patient developed any signs of neurotoxicity and exchange of lumbar cerebro-spinal fluid was started 3 and 5 h later, respectively. In one of the patients, who received 120 mg of methotrexate intrathecally, 31% of the given dose was recovered during 2 h of cerebrospinal fluid exchange that was started 3 h after the accidental overdosage. No sequelae were observed in any of the patients. Cerebrospinal fluid exchange is safe and can be recommended in all cases of intrathecal methotrexate overdosage. Ventriculo-cisternal perfusion is not necessary in cases of a 10-fold overdose if the patient has no signs of acute neurotoxicity.  相似文献   
66.
In children with severe failure of intestinal function, intravenous nutrition is at present the only treatment able to maintain adequate nutrition for prolonged periods of time. Over the last five years we have discharged 10 patients home on parenteral nutrition for a total of 25 patient years and here the outcome of these children is presented. Of the 10 patients, one has discontinued home parenteral nutrition (HPN), seven patients remain well, one patient has recently moved to the USA, and one patient has died after major abdominal surgery. All children had either normal or an accelerated rate of growth on HPN and developmentally all have progressed well. All the children over 5 years attend normal schools. The major complication of treatment was line sepsis with an overall rate of one episode in 476 days and a total of nine central lines (five patients) have required replacement giving an average line life of 680 days. For those children unfortunate enough to suffer from severe intestinal failure, HPN is preferable to prolonged hospital treatment and offers the chance of a good quality of life with prolonged survival.  相似文献   
67.
Objective: To determine the immunity to hepatitis B, poliomyelitis and measles in fully vaccinated Aboriginal and Torres Strait Island children in north Queensland.
Methodology: A cross-sectional survey of immunity in a sample of children; 101 fully vaccinated Aboriginal and Torres Strait Island children, with a median age of 24.5 months, from 10 communities in North Queensland participated in this study. The main outcome measures were the prevalence of adequate antibody levels against hepatitis B, poliomyelitis and measles.
Results: Only 54% (95% Cl 44–63%) of the children had adequate immunity (10 m iu/mL) to hepatitis B, and one child had been infected despite vaccination. Although all the children (95% Cl 96–100%) had adequate immunity (i.e. neutralizing antibodies at a dilution of 1:8) to poliovirus 2, only 93% (95% Cl 86–96%) and 60% (95% Cl 50–69%) had adequate immunity to polioviruses 1 and 3, respectively. Nearly all (96%; 95% Cl 90–98%) of the children had adequate immunity (i.e. detectable IgG antibody) to measles.
Conclusions: Although a relatively low proportion of the children had adequate antibody levels against hepatitis B the clinical significance of this observation is uncertain. Further studies are needed to determine whether fully vaccinated Torres Strait Island children have been adequately protected and whether they require a booster dose of hepatitis B vaccine. A substantial proportion of fully vaccinated Aboriginal and Torres Strait Island children are inadequately protected against poliomyelitis, and therefore any such child with acute flaccid paralysis should be investigated fully for poliomyelitis. Vaccinated Aboriginal and Torres Strait Island children are well protected against measles, as are other Australian children.  相似文献   
68.
This preliminary study was designed to investigate the ability of multiple axial volume three-dimensional fourier transform (3DFT) time-of-flight (TOF) magnetic resonance angiography (MRA) to depict the carotid bifurcation in the early post-carotid endarterectomy period. Five patients underwent intra-operative digital subtraction angiography (DSA) and carotid MRA within 5 days of carotid endarterectomy. An axial volume fast imaging in steady-state precession (FISP) gradient-echo 3DFT TOF carotid MRA technique in this limited series appeared to display accurately the surgically significant abnormalities at the carotid bifurcation after endarterectomy. However, in normal or near-normal intra-operative DSA studies, overestimation of internal carotid artery stenoses was encountered. Postoperative MRA demonstrates potential as a useful non-invasive investigation after carotid endarterectomy but should be interpreted with caution until larger studies become available.  相似文献   
69.
A case of embryonal (botryoid) rhabdomyosarcoma of the nasopharynx originally occurring in a two year old male, with late recurrence in the neck 20 years after treatment by combined surgery and radiotherapy is presented. The histological diagnosis of rhabdomyosarcoma, and the significance of late recurrence are discussed.  相似文献   
70.
Little is known about the vasoactivity of cerebral arterioles in extremely premature infants. We have assessed the effects of a small rise in PaCO2 of 1 kPa (7.5 mm Hg) on cerebral blood flow velocity measured by duplex Doppler ultrasound. Nineteen mechanically ventilated infants of 33 wk gestational age or less in whom direct arterial blood pressure monitoring was available, were studied on 45 occasions. There was a close relationship between increasing PaCO2 and increasing cerebral blood flow velocity (p less than 0.005) but on seven of 45 occasions the cerebral blood flow velocity fell with rising PaCO2. There was a 44% (median value) rise in cerebral blood flow velocity per 1 kPa rise in PaCO2 (5.9%/1 mm Hg) in 21 infants tested within 24 h of birth and this increased to a 53% (median value) rise (7%/1 mm Hg) in 20 infants tested after 24 h (p less than 0.001). Eleven infants had paired studies, the first within 24 h and a second at a median age of 48 h. There was a statistically significant increase in percentage reactivity when the later group was compared to those tested within 24 h (p less than 0.001). Carbon dioxide reactivity was also assessed before and after indomethacin infusion (0.2 mg/kg) on four occasions and there was a reduction in reactivity from a median value of 144 to 49.5%, 10 min after indomethacin. The extremely immature, ill infant is less sensitive to a small change in PaCO2 within 24 h of birth and after indomethacin infusion.(ABSTRACT TRUNCATED AT 250 WORDS)  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