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   514篇
  免费   36篇
  国内免费   8篇
儿科学   51篇
妇产科学   3篇
基础医学   57篇
口腔科学   11篇
临床医学   73篇
内科学   100篇
皮肤病学   2篇
神经病学   9篇
特种医学   136篇
外科学   22篇
综合类   8篇
预防医学   22篇
眼科学   5篇
药学   27篇
中国医学   2篇
肿瘤学   30篇
  2022年   1篇
  2021年   2篇
  2020年   3篇
  2018年   4篇
  2017年   2篇
  2016年   3篇
  2015年   6篇
  2014年   7篇
  2013年   10篇
  2012年   5篇
  2011年   7篇
  2010年   11篇
  2009年   14篇
  2008年   7篇
  2007年   8篇
  2006年   8篇
  2005年   9篇
  2004年   6篇
  2003年   8篇
  2002年   8篇
  2001年   7篇
  2000年   5篇
  1999年   8篇
  1998年   38篇
  1997年   59篇
  1996年   40篇
  1995年   32篇
  1994年   34篇
  1993年   25篇
  1992年   14篇
  1991年   10篇
  1990年   3篇
  1989年   18篇
  1988年   19篇
  1987年   16篇
  1986年   19篇
  1985年   19篇
  1984年   9篇
  1983年   6篇
  1982年   11篇
  1981年   6篇
  1980年   8篇
  1978年   6篇
  1977年   8篇
  1976年   4篇
  1975年   5篇
排序方式: 共有558条查询结果,搜索用时 15 毫秒
61.
We previously have characterized a cluster of genes encoding cathepsin G (CG) and two other CG-like hematopoietic serine proteases, CGL-1 and CGL-2, on human chromosome 14. In this report, we clone and characterize a novel, related murine hematopoietic serine protease gene using human CG (hCG) cDNA as the probe. This murine gene spans approximately 2.5 kb of genomic DNA, is organized into five exons and four introns, and bears a high degree of homology to hCG at both nucleic acid (73%) and deduced amino acid (66%) levels. The predicted cDNA contains an open reading frame of 783 nucleotides that encodes a nascent protein of 261 amino acids. Processing of a putative signal (pre) peptide of 18 residues and an activation (pro) dipeptide would generate a mature enzyme of approximately 27 Kd that has an estimated pI of 12.0. Conserved residues at His44, Asp88, and Ser181 form the characteristic catalytic triad of the serine protease superfamily. The gene is tightly linked to the CTLA-1 locus on murine chromosome 14, where the serine protease genes mCCP1-4 are clustered. Expression of this gene is detected only in the bone marrow and is restricted to a small population of early myeloid cells. These findings are consistent with the identification of the gene encoding murine CG.  相似文献   
62.
Farese  AM; Myers  LA; MacVittie  TJ 《Blood》1994,84(11):3675-3678
The therapeutic efficacy of recombinant human leukemia inhibitory factor (LIF) was examined in a nonhuman primate model of radiation- induced marrow aplasia. Rhesus monkeys received 450 cGy of total-body, 1:1 mixed neutron:gamma radiation. For 23 days thereafter, each monkey received a daily subcutaneous injection of LIF or human serum albumin (HSA) at a dose of 15 micrograms/kg body weight. Complete blood counts and white blood cell differentials were monitored for 60 days postirradiation. Administration of LIF significantly decreased (P < or = .05) the duration of thrombocytopenia (platelet count < 30,000 or 20,000/microL), ie, 9.3 days or 6.3 days, respectively, versus the HSA- treated control monkeys, 12.2 days or 10.2 days, respectively. Treatment with LIF did not alter the duration of neutropenia (absolute neutrophil count < 1,000/microL) as compared with the HSA-treated control monkeys. Cytokine administration did not exacerbate the radiation-induced anemia observed in the HSA-treated control monkeys.  相似文献   
63.

Background

The prevalence of geriatric syndromes (falls, immobility, intellectual or memory impairment, and incontinence) is unknown in many resource-poor countries. With an aging population such knowledge is essential to develop national policies on the health and social needs of older people. The aim of this study was to provide a preliminary survey to explore the prevalence of falls and other geriatric syndromes and their association with known risk factors in people aged > 60 years in urban Blantyre, Malawi.

Methods

This was a cross-sectional, community survey of adults aged > 60 years. Subjects were recruited at home or in the waiting areas of chronic care clinics. They were interviewed to complete a questionnaire on age-associated syndromes and comorbid problems. The Abbreviated Mental Test (AMT) and Timed Up and Go (TUG) tests were carried out.

Results

Ninety-eight subjects were studied; 41% reported falling in the past 12 months, 33% of whom (13% of all subjects) were recurrent fallers. Twenty-five percent reported urine incontinence, 66% self-reported memory difficulties, and 11% had an AMT score < 7. A history of falling was significantly associated with urine incontinence (p=0.01), self-reported memory problems (p=0.004) and AMT score < 7 (p=0.02).

Conclusions

Geriatric syndromes, including falls, appear to be prevalent in older people in Blantyre, Malawi. Falling is associated with cognitive impairment and urinary incontinence. There is an urgent need for more understanding of geriatric problems in this setting to develop national policies on health and social needs of older people. It is likely that many of the contributory factors to falls would be amenable to multifactorial interventions similar to those found to be effective in developed countries.  相似文献   
64.
A 63-year-old man with iron loss anaemia and hypercalcaemia was found to have a renal cell carcinoma. Despite the iron-deficient blood and bone marrow picture, the serum ferritin concentration was markedly raised. This was mainly due to a “basic isoferritin”. The serum parathormone concentration was normal. The serum ferritin and calcium concentrations returned to normal after the tumour was removed. We propose that the renal cell carcinoma cells in this patient secreted the basic isoferritin as well as humoral factor(s) responsible for hypercalcaemia.  相似文献   
65.
The authors demonstrate that it is possible to obtain highly T1-weighted images of the abdomen using a suspended respiration partial saturation (SRPS) method in a breath-holding interval. T2*-weighted images, which reflect tissue T2 as well as variations in the static magnetic field, can also be rapidly obtained. The authors studied five healthy subjects and 19 patients with a variety of liver abnormalities, including benign and malignant hepatic neoplasms, fatty liver infiltration, ascites, and hematoma. On T1-weighted multisection acquisitions, the entire liver can be screened for mass lesions in a single 20-second breath-holding interval. Phase-contrast SRPS images are sensitive to fatty infiltration of the liver. SRPS images are more sensitive to variations in magnetic susceptibility than spin-echo images are, which has been proved to be of value in the detection of hemorrhage. With continued pulse sequence development and clinical study, this method has the potential to become the method of choice for evaluation of the upper abdomen.  相似文献   
66.
67.
68.
Airways and lung: correlation of CT with fiberoptic bronchoscopy   总被引:7,自引:0,他引:7  
Naidich  DP; Harkin  TJ 《Radiology》1995,197(1):1
  相似文献   
69.
70.
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