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   2648篇
  免费   287篇
  国内免费   2篇
耳鼻咽喉   7篇
儿科学   98篇
妇产科学   38篇
基础医学   340篇
口腔科学   61篇
临床医学   407篇
内科学   641篇
皮肤病学   17篇
神经病学   111篇
特种医学   246篇
外科学   280篇
综合类   62篇
预防医学   357篇
眼科学   11篇
药学   175篇
肿瘤学   86篇
  2021年   23篇
  2020年   18篇
  2019年   20篇
  2018年   41篇
  2017年   28篇
  2016年   22篇
  2015年   33篇
  2014年   51篇
  2013年   95篇
  2012年   108篇
  2011年   79篇
  2010年   84篇
  2009年   75篇
  2008年   94篇
  2007年   101篇
  2006年   91篇
  2005年   101篇
  2004年   92篇
  2003年   92篇
  2002年   98篇
  2001年   87篇
  2000年   107篇
  1999年   88篇
  1998年   47篇
  1997年   48篇
  1996年   56篇
  1995年   57篇
  1994年   51篇
  1993年   49篇
  1992年   58篇
  1991年   45篇
  1990年   75篇
  1989年   61篇
  1988年   57篇
  1987年   49篇
  1986年   45篇
  1985年   44篇
  1984年   41篇
  1983年   40篇
  1982年   42篇
  1981年   43篇
  1980年   36篇
  1979年   33篇
  1978年   24篇
  1977年   27篇
  1976年   40篇
  1975年   26篇
  1973年   18篇
  1970年   17篇
  1966年   22篇
排序方式: 共有2937条查询结果,搜索用时 15 毫秒
11.
12.
13.
Fifty of 62 applicants for residential accommodation underwent assessment at a geriatric day hospital. Twenty-five were suitable, 11 were suitable following rehabilitation and 14 were unsuitable for placement in residential accommodation. Around 35% of all applicants were not assessed. Seventy-nine per cent of assessed applicants, without dementia, either were unsure of how their application had been initiated or did not understand the implications of a move to residential accommodation. Twenty-two per cent of all applicants assessed were taking four or more drugs. To maximise the use of residential accommodation, all applicants should be assessed to reduce inappropriate referrals.  相似文献   
14.
Crosslineage T-cell receptor delta (TCR delta) rearrangements are widely used as tumor markers for the follow up of minimal residual disease in childhood B-precursor acute lymphoblastic leukemia (ALL) by polymerase chain reaction (PCR). The major drawback of this approach is the risk of false-negative results due to clonal evolution. We investigated the stability of V delta 2D delta 3 rearrangements in a group of 56 childhood B-precursor ALL patients by PCR and Southern blot analysis. At the PCR level, V delta 2D delta 3-to-J alpha rearranged subclones (one pathway for secondary TCR delta recombination) were demonstrated in 85.2% of V delta 2D delta 3-positive patients tested, which showed that small subclones are present in the large majority of patients despite apparently monoclonal TCR delta Southern blot patterns. Sequence analysis of V delta 2D delta 3J alpha rearrangements showed a biased J alpha gene usage, with HAPO5 and J alpha F in 26 of 32 and 6 of 32 clones, respectively. Comparison of V delta 2D delta 3 rearrangement status between diagnosis and first relapse showed differences in seven of eight patients studied. In contrast, from first relapse onward, no clonal changes were observed in six patients studied. To investigate the occurrence of crosslineage TCR delta rearrangements in normal B and T cells, fluorescence-activated cell sorter-sorted peripheral blood CD19+/CD3- and CD19-/CD3+ cell populations from three healthy donors were analyzed. V delta 2D delta 3 rearrangements were detected at low frequencies in both B and T cells, which suggests that V delta 2-to-D delta 3 joining also occurs during normal B-cell differentiation. A model for crosslineage TCR delta rearrangements in B-precursor ALL is deduced that explains the observed clonal changes between diagnosis and relapse and is compatible with multistep leukemogenesis of B-precursor ALL.  相似文献   
15.
A 15-year experience with 38 aortic graft infections, including 15 patients with graft enteric fistulas, is reviewed in order to analyze modern-day surgical results utilizing extra-anatomic bypass and aortic graft excision. Perioperative mortality was 14% during the most recent 7-year interval, which was a notable improvement compared with the earlier time interval (p = 0.06). Extended follow-up of the perioperative survivors demonstrated a 77% cumulative 5-year survival and a 76% cumulative 5-year limb salvage rate. Subsequent axillofemoral graft infection occurred in 22% of survivors and resulted in a significantly higher amputation rate compared with those patients with no axillofemoral graft infection (p less than 0.001). The results suggest good perioperative and long-term survival in patients with aortic graft infection, with excellent limb salvage if subsequent axillofemoral graft infection can be avoided.  相似文献   
16.
Hypercoagulable states associated with deficiencies in circulating anticoagulant protein C occur after chemotherapy for a variety of malignant diseases. Protein C deficiency also occurs following bone marrow transplantation (BMT) and may be responsible for a variety of transplantation-associated complications. We report the case of a child who suffered a stroke associated with low protein C antigen and activity occurring 11 months after allogeneic BMT. Protein C levels recovered spontaneously by 18 months after BMT. We speculate that the protein C deficiency and and resultant hypercoagulable state led to the stroke, and the deficiency of this anticoagulant was a sequela of the transplant.  相似文献   
17.
18.
All surgical patients are at risk for fluid and electrolyte imbalances. This risk increases when a patient undergoes intestinal surgery, because of the role of the gastrointestinal system in providing the body with water and electrolytes. Therefore, throughout the perioperative period the nurse acts to prevent such disturbances. The nurse who is aware of preoperative factors that contribute to fluid and electrolyte imbalances, including pre-existing patient factors, iatrogenic causes, and the body's response to stress, can help prevent disastrous intraoperative events. Furthermore, postoperative patient assessment can prevent complications such as fluid overload and potassium and sodium imbalances.  相似文献   
19.
This paper discusses the extent of the coverage accorded by national nurses' association journals to the important subject of nursing in other countries. With one exception, the journals sampled showed that dissemination of such information is diminishing. What are the reasons for this?  相似文献   
20.
The N-methyl-D-aspartate (NMDA) receptor complex in brain is a glutamate receptor subtype with several recognition sites including a glycine site that is able to modulate and activate allosterically the receptor. This receptor may be important in the regulation of developmental synaptic plasticity. The release of glutamate and consequent overstimulation of NMDA receptors that follows hypoxia-ischaemia leads to brain damage. Brain tissue obtained at necropsy was studied in a total of 16 term infants aged less than 1 week to 22 weeks and in four adults aged from 66 to 84 years. Glycine sites were determined in brain sections by the binding of the selective ligand [3H]5,7-dichloro-kynurenic acid and measured by autoradiography. In infant brains the amount of binding to the glycine site was higher in temporal cortex and hippocampus than in basal ganglia and was also higher than in comparable areas of adult brain. The amount of glycine site binding in infant cortex increased with postnatal age. The data suggest that infant brain acquires a relatively high density of NMDA receptors in temporal lobe due to postnatal proliferation of glutamatergic synapses. These findings have therapeutic implications as drugs that reduce NMDA receptor function by blocking the glycine modulatory site would be pertinent to preventing brain damage after hypoxia-ischaemia.  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