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   115963篇
  免费   6083篇
  国内免费   137篇
耳鼻咽喉   1773篇
儿科学   5193篇
妇产科学   3928篇
基础医学   16086篇
口腔科学   2830篇
临床医学   8334篇
内科学   21971篇
皮肤病学   3361篇
神经病学   9030篇
特种医学   5049篇
外国民族医学   32篇
外科学   19022篇
综合类   1603篇
一般理论   29篇
预防医学   5814篇
眼科学   3390篇
药学   8043篇
中国医学   323篇
肿瘤学   6372篇
  2018年   890篇
  2017年   777篇
  2016年   1091篇
  2015年   1216篇
  2014年   1599篇
  2013年   2361篇
  2012年   3095篇
  2011年   3143篇
  2010年   1970篇
  2009年   1930篇
  2008年   3254篇
  2007年   3486篇
  2006年   3631篇
  2005年   3742篇
  2004年   3688篇
  2003年   3560篇
  2002年   3520篇
  2001年   7023篇
  2000年   6968篇
  1999年   5870篇
  1998年   1631篇
  1997年   1566篇
  1996年   1335篇
  1995年   1204篇
  1994年   1097篇
  1993年   1130篇
  1992年   3775篇
  1991年   3585篇
  1990年   3568篇
  1989年   3350篇
  1988年   2992篇
  1987年   2901篇
  1986年   2810篇
  1985年   2618篇
  1984年   1943篇
  1983年   1594篇
  1982年   928篇
  1981年   915篇
  1980年   765篇
  1979年   1822篇
  1978年   1346篇
  1977年   1111篇
  1976年   936篇
  1975年   1180篇
  1974年   1212篇
  1973年   1198篇
  1972年   1042篇
  1971年   975篇
  1970年   880篇
  1969年   787篇
排序方式: 共有10000条查询结果,搜索用时 828 毫秒
31.
32.
33.
PURPOSE: In children with locally advanced or recurrent malignant tumours, prognosis can be improved by regional deep hyperthermia (RHT) in combination with platin-based chemotherapy. However, because of the increasing number of patients that achieve long-time remission with this therapy, it is necessary to evaluate long-term sequelae of thermochemotherapy. During the years 1993-2004 one has observed avascular osteonecrosis (AON) of the femoral head after RHT in seven children with pelvic germ cell tumours or rhabdomyosarcomas. METHODS: Although AON may develop in patients with malignancies treated with chemo- or radiotherapy alone, RHT might nevertheless contribute to the occurrence of AON. In order to determine potential risk factors for AON after RHT, this study analysed the relationship of AON to the patient's age, medical history and treatment parameters such as thermal dose equivalent and power output. RESULTS AND CONCLUSIONS: In the present study AON was associated with young age as well as intensity of hyperthermia indicated by high power levels that exceed 20 W per kg body weight and/or application of eight or more heat sessions as well as additional radiotherapy. Based on this observation, it was assumed that an optimized three dimensional thermal field modelling may be helpful to avoid hazardous temperatures in the femoral heads during RHT treatment and to reduce AON of the femoral heads.  相似文献   
34.
35.
The aim of this study was to determine whether patients with sickle cell disease (SCD) in steady state had pulmonary abnormalities seen on high-resolution computed tomography (HRCT) and whether any abnormalities correlated with contemporaneously diagnosed lung function abnormalities. A subsidiary question was whether the results of a noninvasive measure of haemolysis (end-tidal carbon monoxide (ETCO) levels) correlated with pulmonary function abnormalities. Thirty three patients with SCD, median (range) age 36 yrs (17-67 yrs) were examined. The degree of lobar volume loss and ground-glass opacification and prominence of central vessels on HRCT were quantitatively assessed. Pulmonary function was assessed by measurements of lung volumes, spirometry, gas transfer and oxygen saturation. ETCO levels were measured using an end-tidal CO monitor. Forced expiratory volume in one second (FEV1), forced vital capacity and total lung capacity significantly correlated with HRCT findings, particularly lobar volume loss. ETCO levels significantly negatively correlated with FEV1, vital capacity measured using a plethysmograph, specific airway conductance and arterial oxygen saturation measured by pulse oxymetry. In conclusion, the present results suggest that high-resolution computed tomography noninvasive assessment of haemolysis might be useful to identify sickle cell disease patients with respiratory function impairment.  相似文献   
36.
37.
OBJECTIVE: To evaluate the prenatal distribution, associated conditions and outcome of the different types of right aortic arch (RAA) detected in fetal life. METHODS: This was a retrospective review of all cases of RAA detected prenatally between 1998 and 2005 in two tertiary referral centers. RESULTS: In the study period 71 cases of RAA were detected; 26 (37%) had RAA with aberrant left subclavian artery, 23 (32%) had RAA with mirror-image branching, 20 (28%) had RAA of unknown type and two (3%) had double aortic arch. While 20/26 cases with RAA and aberrant left subclavian artery were isolated findings, all 23 cases with RAA and mirror-image branching were associated with cardiac defects, namely tetralogy of Fallot (43%) or pulmonary atresia with ventricular septal defect (22%). Of the 20 cases with RAA, 19 of unknown type were associated with heterotaxy syndromes and had additional cardiac malformations and ambiguities of the situs. The two cases with DAA were isolated findings. Seven cases in our series (10%) had a microdeletion 22q11 and these were significantly associated with extracardiac malformations. The outcome in our series depended solely on the associated cardiac and extracardiac malformations, with the exception of one infant with isolated DAA, in whom a surgical correction was warranted. CONCLUSIONS: RAA detected in fetal life is associated frequently with other cardiac/non-cardiac malformations, heterotaxy syndromes and microdeletions 22q11. The associated conditions vary depending on the branching type of the brachiocephalic vessels and the presence of extracardiac malformations.  相似文献   
38.
At the moment, therapeutic splitting is still regarded by the vast majority of surgeons as the gold standard for stones in the common bile duct. Endoscopic clearance of the duct certainly is much less invasive than open exploration. However, this does not apply when compared with laparoscopic stone removal. Both are equivalent in respect to stone clearance rates, but the laparoscopic techniques protect patients from the long-term sequelae of endoscopic papillotomy. This can be important particularly for younger patients. Laparoscopic bile duct exploration is cost-effective and safe. Special experience in laparoscopic surgical techniques, however, is mandatory. Thus, surgeons should intensify their training in laparoscopic bile duct exploration in order to increase the acceptance of these techniques.  相似文献   
39.
The influence of short‐term confinement and moderate exercise on tibia development was investigated in growing pigs (36–41 kg, 10 weeks at the beginning of the study). Animals were kept for 2 weeks either in individual crates of 0.8 m2 (‘confinement’, n = 4) or kept in groups of four animals in large crates of 5.6 m2 without (‘control’) or with additional exercise (30 min walking at 5 days/week; ‘exercise’). Bone density and morphological parameters were evaluated by computer tomography (CT). Periosteal apposition and longitudinal growth were determined after polychrome sequential labelling in weekly intervals. Cortical areas of the cross sections at the mid‐shaft and at 75% of the length of the bone measured distal to the carpus by CT were significantly correlated to each other (r = 0.70) and revealed a significant reduction in confined animals. This difference was explained by lower periosteal apposition rates in these animals compared with exercised and group‐housed pigs. Similarly longitudinal growth and the formation and calcification of spongiosa of the tibiae were inhibited by confinement. Thus, 2 weeks of confinement led to significant differences in bone growth and metabolism in young growing piglets when compared with animals with moderate activity.  相似文献   
40.
Malignancy larynx usually presents early, the common symptoms being hoarseness, pain thorat, cough and irritation of throat. An advanced malignancy is likely to be complicated by a pharyngo-cutaneous fistula. However it is an occurrence towards the end stage of the disease. Here we present a case of malignancy larynx primarily presenting as pharyngo-cutaneous fistula without any other symptoms.  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