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   2099312篇
  免费   151413篇
  国内免费   5293篇
耳鼻咽喉   28103篇
儿科学   63049篇
妇产科学   55450篇
基础医学   304140篇
口腔科学   60438篇
临床医学   195365篇
内科学   405712篇
皮肤病学   42308篇
神经病学   169978篇
特种医学   78699篇
外国民族医学   432篇
外科学   311875篇
综合类   43788篇
现状与发展   2篇
一般理论   668篇
预防医学   163988篇
眼科学   46850篇
药学   158483篇
  9篇
中国医学   4934篇
肿瘤学   121747篇
  2019年   16111篇
  2018年   23016篇
  2017年   17543篇
  2016年   19212篇
  2015年   21934篇
  2014年   30025篇
  2013年   45854篇
  2012年   62854篇
  2011年   66351篇
  2010年   38859篇
  2009年   36240篇
  2008年   62305篇
  2007年   65563篇
  2006年   66414篇
  2005年   63973篇
  2004年   61351篇
  2003年   58576篇
  2002年   56985篇
  2001年   104469篇
  2000年   107884篇
  1999年   90244篇
  1998年   23431篇
  1997年   21042篇
  1996年   20881篇
  1995年   19669篇
  1994年   18326篇
  1993年   17067篇
  1992年   70495篇
  1991年   68439篇
  1990年   66284篇
  1989年   63733篇
  1988年   58696篇
  1987年   57159篇
  1986年   53997篇
  1985年   51655篇
  1984年   37993篇
  1983年   32259篇
  1982年   18200篇
  1979年   34227篇
  1978年   23683篇
  1977年   19785篇
  1976年   18495篇
  1975年   19518篇
  1974年   23815篇
  1973年   22889篇
  1972年   21434篇
  1971年   20183篇
  1970年   18924篇
  1969年   17492篇
  1968年   16356篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
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   
64.
65.
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   
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.
Published data devoted to making and characterization of the properties of polymeric wound dressings with proteolytic action are reviewed. These data are indicative of individual dependence of the physicochemical properties, activity, and stability of each particular enzyme on the type of polymer matrix and the method of immobilization. In order to obtain wound dressings, which are active in physiological medium and retain their activity upon sterilization, it is necessary to optimize the composition and characteristics of a polymer matrix and the enzyme included into its structure. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 8, pp. 24–28, August, 2006.  相似文献   
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