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   523篇
  免费   33篇
  国内免费   12篇
耳鼻咽喉   32篇
儿科学   43篇
妇产科学   23篇
基础医学   49篇
口腔科学   10篇
临床医学   65篇
内科学   104篇
皮肤病学   9篇
神经病学   17篇
特种医学   74篇
外科学   36篇
综合类   17篇
预防医学   18篇
眼科学   6篇
药学   36篇
肿瘤学   29篇
  2021年   3篇
  2020年   8篇
  2019年   11篇
  2018年   9篇
  2017年   14篇
  2016年   6篇
  2015年   9篇
  2014年   15篇
  2013年   23篇
  2012年   13篇
  2011年   14篇
  2010年   25篇
  2009年   21篇
  2008年   9篇
  2007年   15篇
  2006年   21篇
  2005年   15篇
  2004年   13篇
  2003年   14篇
  2002年   5篇
  2001年   10篇
  2000年   12篇
  1999年   18篇
  1998年   31篇
  1997年   21篇
  1996年   23篇
  1995年   20篇
  1994年   18篇
  1993年   14篇
  1992年   12篇
  1990年   8篇
  1989年   8篇
  1988年   8篇
  1987年   10篇
  1986年   11篇
  1985年   5篇
  1984年   4篇
  1983年   6篇
  1982年   5篇
  1981年   5篇
  1980年   3篇
  1979年   5篇
  1978年   3篇
  1977年   5篇
  1976年   8篇
  1975年   3篇
  1973年   3篇
  1972年   4篇
  1960年   2篇
  1955年   2篇
排序方式: 共有568条查询结果,搜索用时 476 毫秒
1.
It is well known that hepatitis C virus (HCV)-related chronic liver disease may be associated with various immunological disorders including mixed cryoglobulinemia, which is accompanied by cutaneous vasculitis, arthralgias, membranoproliferative glomerulonephritis, and neuropathy in association with cryoprecipitable immune complexes in serum. We describe here the first case of central nervous system HCV infection with evidence of the virus in the cerebrospinal fluid in association with cryoglobulinemia in a patient who developed recurrent episodes of papillitis and vasculitis of the arteria spinalis anterior after liver transplantation. Received: 3 September 1996 Received after revision: 13 November 1996 Accepted: 6 December 1996  相似文献   
2.
3.
To study the function of the protooncogene Mos in mouse brain development we have created a transgenic mouse model system in which an activated form of the gene, the murine retroviral v-Mos gene, is highly overexpressed in the brain. Six transgenic founder animals and mice of one established transgenic line (line TG66) displayed a progressive hind limb paralysis with onset between 18 days and 9 months. The severity of the neurological phenotype correlated with pathological alterations and the degree of v-Mos expression in the brain which varied between individual animals of line TG66. The most striking feature of the brain pathology was the presence of large, abnormal astrocytes in the cerebellum, medulla, thalamus and in the dorsal horn of the spinal cord. These areas also contained shrunken and basophilic neurons whose cytoplasm was abnormally immunoreactive for phosphorylated epitopes of neurofilaments. In addition to neuropathologic changes, these mice also displayed aberrant eye lens differentiation and absence of hair cells in the inner ear. These results establish v-Mos transgenic mice as a model system to study progressive neurodegenerative disease and provide further evidence that the Mos protein-serine/threonine kinase has a function in brain development.  相似文献   
4.
5.
Silane-coated silica particle solutions (ISolate(TM) and PureSperm)TM)) and iodixanol (OptiPrep(TM)) were compared to polyvinylpyrrolidone (PVP)-coated silica particles (Percoll(TM)) in their efficacy to recover spermatozoa by gradient centrifugation for use in assisted reproductive procedures. Efficacy was assessed in terms of percentages of sperm recovery, sperm vitality and motility, normal sperm morphology and normal sperm chromatin condensation. No significant difference was found in the recovery of spermatozoa for men with both normal sperm counts and oligozoospermia, between PVP-coated and silane-coated particle solutions. Iodixanol had significantly lower sperm recovery compared to the other products. Sperm vitality, progressive motility, normal morphology and normal chromatin condensation did not differ significantly between any of the sperm isolation products.   相似文献   
6.
The tumour suppressor gene PTEN , which maps to 10q23.3 and encodes a 403 amino acid dual specificity phosphatase (protein tyrosine phosphatase; PTPase), was shown recently to play a broad role in human malignancy. Somatic PTEN deletions and mutations were observed in sporadic breast, brain, prostate and kidney cancer cell lines and in several primary tumours such as endometrial carcinomas, malignant melanoma and thyroid tumours. In addition, PTEN was identified as the susceptibility gene for two hamartoma syndromes: Cowden disease (CD; MIM 158350) and Bannayan-Zonana (BZS) or Ruvalcaba-Riley-Smith syndrome (MIM 153480). Constitutive DNA from 37 CD families and seven BZS families was screened for germline PTEN mutations. PTEN mutations were identified in 30 of 37 (81%) CD families, including missense and nonsense point mutations, deletions, insertions, a deletion/insertion and splice site mutations. These mutations were scattered over the entire length of PTEN , with the exception of the first, fourth and last exons. A 'hot spot' for PTEN mutation in CD was identified in exon 5 that contains the PTPase core motif, with 13 of 30 (43%) CD mutations identified in this exon. Seven of 30 (23%) were within the core motif, the majority (five of seven) of which were missense mutations, possibly pointing to the functional significance of this region. Germline PTEN mutations were identified in four of seven (57%) BZS families studied. Interestingly, none of these mutations was observed in the PTPase core motif. It is also worthy of note that a single nonsense point mutation, R233X, was observed in the germline DNA from two unrelated CD families and one BZS family. Genotype-phenotype studies were not performed on this small group of BZS families. However, genotype-phenotype analysis inthe group of CD families revealed two possible associations worthy of follow-up in independent analyses. The first was an association noted in the group of CD families with breast disease. A correlation was observed between the presence/absence of a PTEN mutation and the type of breast involvement (unaffected versus benign versus malignant). Specifically and more directly, an association was also observed between the presence of a PTEN mutation and malignant breast disease. Secondly, there appeared to be an interdependent association between mutations upstream and within the PTPase core motif, the core motif containing the majority of missense mutations, and the involvement of all major organ systems (central nervous system, thyroid, breast, skin and gastrointestinal tract). However, these observations would need to be confirmed by studying a larger number of CD families.   相似文献   
7.
We report our clinical experience with phototherapy in 3802 infants; 3629 were exposed to "standard" daylight phototherapy and 173 to "high-intensity" blue-light phototherapy. High-intensity blue-light phototherapy was twice as effective as standard daylight phototherapy in decreasing bilirubin concentrations. No failures occurred with high-intensity phototherapy compared with an overall failure rate of 1.84/1000 with daylight lamps; these cases were transferred to high-intensity phototherapy with prompt response. Rebound after cessation of phototherapy was greater in those exposed to high-intensity blue light with a significantly greater number requiring a second exposure. However, the incidence was still low. No third exposure was required in any infant. Nursing of infants under high-intensity blue light was more difficult and inconvenient as was clinical monitoring. The light also caused more stress on the nursing and medical personnel. However, the infants tolerated both types of phototherapy equally well. High-intensity blue-light phototherapy would seem to be the treatment of choice for infants with rapidly increasing or very high bilirubin levels, as well as in those not responding adequately to daylight phototherapy.  相似文献   
8.
Abstract: We report the first case of fatal anthrax meningoencephalitis in Hong Kong over the past 60 years. A 13 year-old boy presented with right lower quadrant pain, diarrhoea and progressive headache. Lumbar puncture yielded gram positive bacilli initially thought to be Bacillus cereus, a contaminant. He was treated with ampicillin and cefotaxime, but died 3 days after hospitalization. The organism isolated from blood and cerebrospinal fluid was later identified as Bacillus anthracis.  相似文献   
9.
Erythromycin treatment for gastrointestinal dysmotility in preterm infants   总被引:3,自引:0,他引:3  
To report our clinical experience on the use of oral erythromycin for the treatment of severe gastrointestinal dysmotility in preterm infants.

Methodology:


A case series study of seven preterm infants (six were very low birthweight) with severe intestinal dysmotility in a tertiary neonatal centre.

Results:


All responded favourably without adverse effects and tolerated full enteral feeding within 1–2 weeks of the commencement of the drug.

Conclusions:


As prolonged total parenteral nutrition carries significant risk of complications, this therapy could be considered in selected preterm infants who fail to establish enteral feeding after an extended period, and in whom an anatomically obstructive lesion of the gastrointestinal tract has been excluded. Meanwhile, we would caution against the widespread implementation of this therapeutic approach until formal evaluation by randomized controlled trials have established the exact role of erythromycin, or its analogues, in the treatment of intestinal dysmotility in preterm infants.  相似文献   
10.
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