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   1856篇
  免费   89篇
  国内免费   5篇
耳鼻咽喉   10篇
儿科学   114篇
妇产科学   33篇
基础医学   216篇
口腔科学   48篇
临床医学   183篇
内科学   500篇
皮肤病学   29篇
神经病学   58篇
特种医学   464篇
外科学   111篇
综合类   42篇
预防医学   31篇
眼科学   6篇
药学   57篇
  1篇
中国医学   1篇
肿瘤学   46篇
  2022年   9篇
  2021年   28篇
  2020年   12篇
  2019年   35篇
  2018年   21篇
  2017年   19篇
  2016年   12篇
  2015年   20篇
  2014年   38篇
  2013年   51篇
  2012年   48篇
  2011年   37篇
  2010年   39篇
  2009年   67篇
  2008年   43篇
  2007年   55篇
  2006年   52篇
  2005年   47篇
  2004年   32篇
  2003年   30篇
  2002年   18篇
  2001年   28篇
  2000年   18篇
  1999年   28篇
  1998年   84篇
  1997年   81篇
  1996年   80篇
  1995年   67篇
  1994年   45篇
  1993年   59篇
  1992年   11篇
  1991年   23篇
  1990年   33篇
  1989年   63篇
  1988年   50篇
  1987年   59篇
  1986年   67篇
  1985年   91篇
  1984年   47篇
  1983年   36篇
  1982年   29篇
  1981年   35篇
  1980年   39篇
  1979年   12篇
  1978年   22篇
  1977年   24篇
  1976年   24篇
  1975年   20篇
  1931年   11篇
  1930年   17篇
排序方式: 共有1950条查询结果,搜索用时 15 毫秒
101.
OBJECT: The goals of this study were to define the incidence of seizures in children with low-grade tumors, study seizure outcome after lesionectomy in these children, and identify risk factors for poor seizure outcome, METHODS: The authors performed a retrospective chart review of children who harbored low-grade brain tumors, experienced seizures, and were treated in a single institution, Statistical analyses included step-wise as well as single-variable binary logistic regression analyses.  相似文献   
102.
103.
104.
The present report describes psychobiological studies of behavior around the time of birth. An adaptive, ecological perspective is presented in which stimulation of the fetus and newborn is purported to instigate adaptive postpartum behavior. Studies describing the perinatal sensory environment are reviewed, with a consideration of emergent sensory function of the fetus. It is asserted that afferent input associated with parturition perturbs the fetus and neonate, producing a general arousal state that facilitates breathing, suckling, and early learning. The view developed herein is that perinatal sensory input induces and canalizes the newborn's behavior, thereby regulating adaptive postpartum function. Deviations in afferent input may alter ontogenetic trajectories and compromise developmental outcome by reducing availability of conditions necessary for adequate postpartum adaptation.  相似文献   
105.
OBJECTIVE: To investigate the frequency of lumbosacral anomalies, the association with urogenital abnormalities, and the correlation with defaecation pattern by magnetic resonance imaging (MRI). METHODS: A prospective analysis was performed of routine MRI in patients with anorectal malformations. Between 1990 and 1994, MRI was performed in 43 such patients: 31 boys and 12 girls. Twenty four had a high anorectal malformation, 16 had a low anorectal malformation, and three had Currarino's triad. MRI was performed before reconstruction in 26, and postoperatively in 17. Urogenital anomalies were found in 21. RESULTS: Abnormalities of the spinal cord and spine were found with MRI in 20 patients (46.5%); caudal regression syndrome in 10, tethered cord in two, a combination of both in three, and other spinal anomalies in five. These anomalies were found in 30% of the patients with low anorectal malformations, and in 50% with high anorectal malformations. In patients with urogenital malformations, MRI more often showed spinal anomalies (13/21, 62%) than in patients without (7/22, 32%). In high anorectal malformations, defaecation was more often a problem in patients with spinal anomalies (12/15, 80%) than in patients without (2/8, 25%). CONCLUSIONS: Spinal anomalies in the lumbosacral region were found with MRI in 46.5% of patients with anorectal malformations. Since presence of these anomalies seems to be related to clinical outcome, MRI should be performed routinely in all such patients.  相似文献   
106.
Whole body protein synthesis and catabolism were measured using the [ring-2H5]phenylalanine and [1-13C]leucine primed constant infusion technique in 32 paediatric patients with cancer at different stages of treatment. Rates of synthesis (S) and catabolism (C) derived from the [ring-2H5]phenylalanine and [1-13C]leucine models were 4.7 (SD 1.3) (S) and 6.0 (1.5) (C) g/d/kg, and 5.5 (0.8) (S) and 6.8 (1.2) (C) g/d/kg, respectively. These results show that these two tracer techniques give similar results in this study population. Comparison of these values with results previously reported for groups of control children using the [ring-2H5]phenylalanine model (S = 3.69 and 3.93; C = 4.09 and 4.28 g/d/kg) and the [1-13C]leucine model (S = 4.32; C = 4.85 g/d/kg) show that rates of synthesis and catabolism were higher in cancer patients than in controls. Thus whole body protein turnover is increased in children under treatment for cancer. Other indices of metabolism such as plasma amino acids and intermediary metabolites were also measured and showed that, although subjects were in isotopic steady state, there were significant metabolic changes during the course of the primed constant infusions used to measure protein turnover.  相似文献   
107.
Between 1991 and 1993, 106 newly diagnosed cases of Hirschsprung's disease (HD) were prospectively analyzed for the association of HD and intestinal neuronal dysplasia (IND) at ten pediatric surgical departments in central Europe. Hirschsprung-associated IND (HaIND) was found in 40% of cases. IND was disseminated in one-third and localized in two-thirds of the patients. Initial clinical symptoms were related to the length of the aganglionic segment, but not to the presence of HaIND. An enterostomy performed in 72 cases (67.9%) was located in a segment of pathologically innervated bowel in 50% of all cases, but in 72% of cases of HaIND. The proximal margin of the resected bowel showed pathological innervation in 44% of cases. Supplemental biopsies from the intestine (apart from diagnostic suction biopsies and biopsies at the enterostomy site) led to the first identification or definition of length of associated IND in 17.9% of cases. Postoperatively, the presence of long-segment aganglionosis or associated IND implied a delay in the restoration of normal defecation. Persistent constipation was found in 40% of patients with associated disseminated IND at follow-up at 6 months, compared to 20.6% in patients with isolated HD. These children needed secondary interventions more often than patients with associated localized IND or isolated HD. HaIND thus has clinical implications for the postoperative course if IND is disseminated. Accepted: 25 April 1999  相似文献   
108.
109.
Widespread Castleman disease: CT and US findings   总被引:4,自引:0,他引:4  
The widespread form of Castleman disease is a rare condition that has been recognized only recently as a disease with an aggressive, often malignant course. The authors present computed tomographic (CT) findings in six patients with this condition and ultrasound (US) findings in four of the six. CT demonstrated splenomegaly and retroperitoneal lymphadenopathy in all six patients. In one patient, CT also showed additional widespread mesenteric and peripancreatic lymphadenopathy, a large mesenteric mass adherent to the descending colon in another, and mediastinal lymphadenopathy in a third. Three patients had peripheral axillary or inguinal lymphadenopathy. Enlarged lymph nodes were 1-4 cm in diameter, and none displayed contrast enhancement on CT scans obtained with drip infusion of contrast media. On US scans, the nodes were poorly echogenic in all four cases. In no case was focal liver or splenic infiltration seen on either CT or US scans.  相似文献   
110.
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