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   2617875篇
  免费   187089篇
  国内免费   6283篇
耳鼻咽喉   35056篇
儿科学   86206篇
妇产科学   73006篇
基础医学   375590篇
口腔科学   74998篇
临床医学   241861篇
内科学   501214篇
皮肤病学   54274篇
神经病学   214063篇
特种医学   99256篇
外国民族医学   804篇
外科学   378406篇
综合类   62479篇
现状与发展   4篇
一般理论   958篇
预防医学   212964篇
眼科学   59156篇
药学   194850篇
  69篇
中国医学   5463篇
肿瘤学   140570篇
  2018年   27522篇
  2017年   21158篇
  2016年   23347篇
  2015年   26690篇
  2014年   36793篇
  2013年   56758篇
  2012年   77226篇
  2011年   81871篇
  2010年   48044篇
  2009年   45079篇
  2008年   76577篇
  2007年   80863篇
  2006年   81495篇
  2005年   79105篇
  2004年   76704篇
  2003年   73179篇
  2002年   71532篇
  2001年   116992篇
  2000年   120891篇
  1999年   102053篇
  1998年   28853篇
  1997年   26231篇
  1996年   25960篇
  1995年   25084篇
  1994年   23566篇
  1993年   22260篇
  1992年   83416篇
  1991年   81621篇
  1990年   79445篇
  1989年   76293篇
  1988年   70972篇
  1987年   69643篇
  1986年   66416篇
  1985年   63953篇
  1984年   48091篇
  1983年   41302篇
  1982年   24693篇
  1981年   21985篇
  1979年   45121篇
  1978年   31714篇
  1977年   26535篇
  1976年   25346篇
  1975年   26569篇
  1974年   32468篇
  1973年   31439篇
  1972年   28938篇
  1971年   27170篇
  1970年   25043篇
  1969年   23257篇
  1968年   21754篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
61.
62.
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   
63.
64.
Cutaneous plasmacytosis is a rare disorder characterized by a benign proliferation of mature plasma cells that appears as multiple dark-brown to purplish skin lesions, often associated with polyclonal hypergammaglobulinaemia. We present the case of a 55-year-old Caucasian man who suffered from a cutaneous plasmacytosis associated with two different carcinomas. Cutaneous plasmacytosis seems to be a reactive process because most cases reported are not associated with any apparent underlying disease. Nevertheless, because few reported cases were associated with malignancies, screening of additional neoplasms would be justified.  相似文献   
65.
66.
Patients with multiple system atrophy (MSA) present large changes in blood pressure (BP) due to autonomic disturbances. We analyzed how this change may influence dynamic cerebral autoregulation (DCA). Simultaneous recordings of arterial BP (Finapres) and middle cerebral artery (MCA) blood flow velocity (BFV) (transcranial Doppler) were performed in 10 patients with MSA (61 +/- 12 yr of age) and 12 healthy volunteers (61 +/- 11 yr of age): cerebral BFV response to oscillations in mean BP was studied in the supine position by cross-spectral analysis of mean BP and mean MCA BFV. The DCA was also studied during the decrease in BP the first seconds when standing up from a sitting position by the assessment of the cerebrovascular resistance index (CR; mean BP/mean MCA BFV ratio). The MCA BFV/BP cross-spectral analysis showed a phase for the mid-frequency band (0.07-0.2 Hz) significantly larger in MSA, suggesting more active autoregulation in response to larger changes in BP. Changes in CR reflecting the rate of autoregulation, when standing did not differ between the two groups. These data suggest that dynamic cerebral autoregulation is preserved in MSA.  相似文献   
67.
68.
69.
70.
Pre-eclamptic toxaemia (PET) may be associated with both endothelial dysfunction (ED) and sleep-disordered breathing (SDB). It was hypothesised that females with PET would demonstrate both SDB and ED, and that a correlation between these two would suggest a potential causative association. A total of 17 females with PET and 25 matched females with uncomplicated pregnancy were studied. They underwent a nocturnal ambulatory sleep study (using Watch_PAT100) and noninvasive evaluation of endothelial function utilising the reactive hyperaemia test (using Endo_PAT 2000). A higher ratio of post- to pre-occlusion pulse-wave amplitude (endothelial function index (EFI)) indicated better endothelial function. Females with PET had a significantly higher respiratory disturbance index (RDI) and lower EFI than controls (18.4+/-8.4 versus 8.3+/-1.3.h(-1), and 1.5+/-0.1 versus 1.8+/-0.1, respectively). Blood pressure significantly correlated with RDI and with EFI. EFI tended to correlate with RDI. In conclusion, these results suggest that both sleep-disordered breathing and endothelial dysfunction are more likely to occur in females with pre-eclamptic toxaemia than in females with uncomplicated pregnancies. The current authors speculate that respiratory disturbances contribute to the functional abnormality of the blood vessels seen in females with pre-eclamptic toxaemia, although causality cannot be determined based on this study.  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