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   3070篇
  免费   135篇
  国内免费   60篇
耳鼻咽喉   8篇
儿科学   172篇
妇产科学   45篇
基础医学   394篇
口腔科学   63篇
临床医学   357篇
内科学   696篇
皮肤病学   69篇
神经病学   220篇
特种医学   349篇
外科学   184篇
综合类   53篇
预防医学   233篇
眼科学   50篇
药学   153篇
  2篇
中国医学   9篇
肿瘤学   208篇
  2023年   10篇
  2022年   40篇
  2021年   65篇
  2020年   38篇
  2019年   46篇
  2018年   63篇
  2017年   53篇
  2016年   57篇
  2015年   75篇
  2014年   98篇
  2013年   106篇
  2012年   131篇
  2011年   154篇
  2010年   128篇
  2009年   101篇
  2008年   131篇
  2007年   144篇
  2006年   128篇
  2005年   141篇
  2004年   94篇
  2003年   88篇
  2002年   80篇
  2001年   37篇
  2000年   33篇
  1999年   32篇
  1998年   127篇
  1997年   133篇
  1996年   107篇
  1995年   90篇
  1994年   99篇
  1993年   83篇
  1992年   26篇
  1991年   35篇
  1990年   31篇
  1989年   45篇
  1988年   40篇
  1987年   35篇
  1986年   38篇
  1985年   46篇
  1984年   26篇
  1983年   16篇
  1982年   23篇
  1981年   24篇
  1980年   24篇
  1979年   10篇
  1978年   15篇
  1977年   29篇
  1976年   23篇
  1975年   14篇
  1970年   5篇
排序方式: 共有3265条查询结果,搜索用时 15 毫秒
61.
Kwong DL  Pow EH  Sham JS  McMillan AS  Leung LH  Leung WK  Chua DT  Cheng AC  Wu PM  Au GK 《Cancer》2004,101(7):1584-1593
BACKGROUND: Xerostomia is a uniform complication after radiotherapy (RT) for nasopharyngeal carcinoma (NPC). Dosimetric studies suggested that intensity-modulated RT (IMRT) can spare part of the parotid glands from high-dose radiation. Disease control and salivary function after IMRT for early-stage NPC was studied prospectively. METHODS: Thirty-three patients with T1,N0-N1,M0 NPC were treated with IMRT from 2000 to 2002. The prescribed dose was 68-70 grays (Gy) in 34 fractions to gross tumor volume, 64-68 Gy to the planning target volume, and 70 Gy to enlarged cervical lymph nodes. Nineteen patients had stimulated whole salivary (SWS) flow assessment and stimulated parotid salivary (SPS) flow assessment at baseline and at 2 months, 6 months, 12 months, 18 months, and 24 months after the completion of IMRT. RESULTS: At a median follow-up of 2 years, only 1 neck failure was observed. The 2-year and 3-year local control, distant metastases-free, and overall survival rates all were 100%. The lymph node control and progression-free survival rates were 100% at 2 years and 92.3% at 3 years, respectively. The average mean dose to the parotid gland was 38.8 Gy. The SWS and SPS flow showed continuous recovery: 60% and 47.1% of patients recovered at least 25% of their baseline SPS flow and SWS flow, respectively, at 1 year after completion of IMRT, and the proportions rose to 85.7% and 71.4%, respectively, by 2 years. The pH and buffering capacity of saliva also improved with time. CONCLUSIONS: Parotid-sparing IMRT achieved good locoregional control, and there was continuous recovery of salivary flow, pH, and buffering capacity in the first 2 years after IMRT in patients with NPC.  相似文献   
62.
OBJECTIVES: To determine whether there is a difference in maternal and neonatal outcomes if a sequential operative vaginal or cesarean delivery follows failed vacuum delivery. STUDY DESIGN: A cross sectional study. We have analyzed maternal and neonatal outcomes of 215 vacuum extractions (group 1), 106 forceps assisted deliveries (group 2), 28 deliveries in which failed vacuum extraction were followed by forceps delivery (group 3) and 22 deliveries in which failed vacuum extraction were followed by cesarean delivery (group 4). RESULTS: Compared to other groups, patients in group 4 had significantly more post partum anemia, meconium stained amniotic fluid and hospital stay (both maternal and neonatal) as well as lower pH. Apgar scores were similar in groups 3 and 4. Incidence of respiratory distress syndrome, cephalhematoma and jaundice were similar in neonates of all groups. CONCLUSIONS: If an attempted vacuum delivery has failed, the risk of adverse neonatal outcome is increased with either subsequent forceps or cesarean delivery. It should remain in the judgment of the attending obstetrician to choose the method most suitable under the given circumstances.  相似文献   
63.
64.
65.
We report a patient with a peripheral neuropathy as the first symptom of sarcoidosis. The systemic illness was proved by the presence of typic granulomes in the bone marrow. The fact that sarcoidosis is the cause for the neuropathy is supported by the temporary relation and by the good response of all clinical picture to the corticosteroid therapy.Sarcoid neuropathy can rarely be the presenting feature of sarcoidosis.  相似文献   
66.
OBJECTIVE: Because survival from admission to discharge does not provide parents and physicians information about future life expectancy in the premature neonate, we characterized the actuarial survival, defined as the future life expectancy from a given postnatal age, in a large inborn population of premature infants < 30 weeks' gestation. STUDY DESIGN: We determined daily actuarial survival of 1925 inborn infants (23 to 29 weeks' gestation) admitted to the Baylor Affiliated Nurseries from July 1986 through December 1994, stratified by 100-g birth weight and by 1-week gestational-age intervals. RESULTS: In the 501- to 600-g birth weight stratum, actuarial survival improved from 31% at birth, to 61% on day of life 7, and then to 75% on day of life 28; in the 901- to 1000-g birth weight stratum, actuarial survival improved from 88%, to 94%, and then to 98% throughout the same times, respectively. Similar trends were obtained when data were stratified by gestational age. CONCLUSIONS: Survival in the smallest infants improves dramatically during the first few days of life, but there is a significant risk for late death in the smallest of these infants.  相似文献   
67.
OBJECTIVE: The ketogenic diet is a high-fat, low-protein, low-carbohydrate diet developed in the 1920s for the treatment of children with difficult to control seizures. Despite advances in both the pharmacotherapy and the surgery of epilepsy, many children continue to have difficult-to-control seizures. This prospective study sought to determine the ketogenic diet's effectiveness and tolerability in children refractory to today's medications. METHODS: One hundred fifty consecutive children, ages 1 to 16 years, virtually all of whom continued to have more than two seizures per week despite adequate therapy with at least two anticonvulsant medications, were prospectively enrolled in this study, treated with the ketogenic diet, and followed for a minimum of 1 year. Seizure frequency was tabulated from patients' daily seizure calendars and seizure reduction calculated as percentage of baseline frequency. Adverse events and reasons for diet discontinuation were recorded. RESULTS: The children (mean age, 5.3 years), averaged 410 seizures per month before the diet, despite an exposure to a mean of 6.2 antiepileptic medications. Three months after diet initiation, 83% of those starting remained on the diet and 34% had >90% decrease in seizures. At 6 months, 71% still remained on the diet and 32% had a >90% decrease in seizures. At 1 year, 55% remained on the diet and 27% had a >90% decrease in seizure frequency. Most of those discontinuing the diet did so because it was either insufficiently effective or too restrictive. Seven percent stopped because of intercurrent illness. CONCLUSIONS: The ketogenic diet should be considered as alternative therapy for children with difficult-to-control seizures. It is more effective than many of the new anticonvulsant medications and is well tolerated by children and families when it is effective.  相似文献   
68.
69.
Persistent hyperinsulinemic hypoglycaemia of infancy (PHHI) is the most frequent cause of hypoglycaemia in infancy. Clinical presentation is heterogeneous, with variable onset of hypoglycaemia and response to diazoxide, and presence of sporadic or familial forms. Underlying histopathological lesions can be focal or diffuse. Focal lesions are characterised by focal hyperplasia of pancreatic islet-like cells, whereas diffuse lesions implicate the whole pancreas. The distinction between the two forms is important because surgical treatment and genetic counselling are radically different. Focal lesions correspond to somatic defects which are totally cured by limited pancreatic resection, whereas diffuse lesions require a subtotal pancreatectomy exposing to high risk of diabetes mellitus. Diffuse lesions are due to functional abnormalities involving several genes and different transmission forms. Recessively inherited PHHI have been attributed to homozygote mutations for the beta-cell sulfonylurea receptor (SUR1) or the inward-rectifying potassium-channel (Kir6.2) genes. Dominantly inherited PHHI can implicate the glucokinase gene, particularly when PHHI is associated with diabetes, the glutamate dehydrogenase gene when hyperammonaemia is associated, or another locus.  相似文献   
70.
Objective : To describe survival patterns, use of health services and related costs for Australian children with perinatally acquired human immunodeficiency virus (HIV) infection.
Methodology : A retrospective cross-sectional survey was made of 20 children with HIV infection (91% of those diagnosed) and 13 children with maternal antibodies who subsequently seroreverted, treated at 10 medical centres. Details of disease progression and use of health services were obtained from hospital medical records. Monthly costs for three phases of infection were estimated by linking service usage rates with estimates of the unit cost of each service. The average lifetime cost was estimated by combining monthly costs and phase duration estimates from the literature.
Results : Patterns of disease progression were similar to those reported internationally, with a median survival of 8 years. Use, of health services increased with severity of illness. Mean monthly costs were $120 per month (1992 Australian dollars) for children with maternal antibodies who subsequently seroreverted, $320 per month for children with HIV infection but no acquired immunodeficiency syndrome (AIDS)-defining illness, and $1830 per month for children with AIDS. The present value of total lifetime cost for a child with HIV infection was $48174,46% of which was for treatment of AIDS.
Discussion : The mean lifetime cost for a perinatally infected child was just over half that for a man with HIV in Australia. Health service usage and costs were lower for Australian than American children with HIV.  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