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   748篇
  免费   63篇
  国内免费   18篇
耳鼻咽喉   5篇
儿科学   29篇
妇产科学   6篇
基础医学   69篇
口腔科学   15篇
临床医学   81篇
内科学   224篇
皮肤病学   5篇
神经病学   39篇
特种医学   48篇
外科学   189篇
综合类   13篇
预防医学   48篇
眼科学   4篇
药学   19篇
中国医学   1篇
肿瘤学   34篇
  2023年   3篇
  2022年   3篇
  2021年   8篇
  2020年   6篇
  2019年   11篇
  2018年   15篇
  2017年   9篇
  2016年   7篇
  2015年   20篇
  2014年   18篇
  2013年   23篇
  2012年   26篇
  2011年   22篇
  2010年   29篇
  2009年   38篇
  2008年   26篇
  2007年   34篇
  2006年   24篇
  2005年   34篇
  2004年   39篇
  2003年   29篇
  2002年   30篇
  2001年   19篇
  2000年   16篇
  1999年   24篇
  1998年   30篇
  1997年   29篇
  1996年   20篇
  1995年   14篇
  1994年   17篇
  1993年   11篇
  1992年   15篇
  1991年   13篇
  1990年   10篇
  1989年   9篇
  1988年   22篇
  1987年   17篇
  1986年   19篇
  1985年   18篇
  1984年   8篇
  1983年   5篇
  1982年   13篇
  1980年   3篇
  1978年   5篇
  1977年   5篇
  1976年   4篇
  1975年   3篇
  1974年   4篇
  1973年   5篇
  1967年   2篇
排序方式: 共有829条查询结果,搜索用时 140 毫秒
1.
BACKGROUND: On December 26, 2004, the biggest earthquake for 40 years, measuring 9.0 on the Richter scale, triggered a tsunami that pounded the coastal areas of South Asia and East Africa. The effects of the tsunami on skin conditions have not been evaluated. OBJECTIVE: To determine the influence of the tsunami on skin conditions by evaluating the skin problems of patients presenting at hospitals after the tsunami. METHODS: Between 5 and 25 January 2005, two dermatologists evaluated patients who complained of skin problems at an outpatient clinic and emergency room of a general hospital in Banda Aceh, Aceh Province, Indonesia. RESULTS: The total number of patients that presented during the study period was 235 (131 males and 104 females), and they had a total of 265 skin problems. In terms of age distribution, most subjects were in their fourth decade (23.0%), followed by the third (22.6%) and fifth decade (16.6%). The most prevalent skin problems were infections-infestations (32.5%), followed by eczemas (29.8%) and traumatic skin disorders (29.4%). In males, traumatic skin disorders were most common. The great majority of infection-infestation cases involved superficial fungal infections. Contact dermatitis accounted for three-quarters of eczema cases, and mainly involved the arms (40.0%) and legs (27.1%). The majority of traumatic skin disorders were lacerations, punctures and penetrations, and the feet (44.7%) and hands (18.8%) were most frequently affected. CONCLUSIONS: Unhygienic conditions, exposure to a hazardous environment and contact with various objects during and after the tsunami probably increased the prevalence of infections-infestations, traumatic skin disorders and contact dermatitis. To prevent these problems and associated secondary bacterial infections, health-related education and early medical management are required.  相似文献   
2.
3.
4.
5.
Cell transplantation to improve ventricular function in the failing heart   总被引:9,自引:0,他引:9  
Current therapies for congestive heart failure are limited in efficacy or in applicability. Cardiac cell transplantation offers a novel therapeutic approach to improve heart function. Although significant progress has been made over the past decade in the development of cell transplantation, only recently have investigators studied the changes in ventricular function following cell transplantation. This review article describes the latest research developments, evaluates recent studies of ventricular function after cell transplantation, and discusses the future directions of cell transplantation as a new therapy to ‘repair broken hearts’.  相似文献   
6.
An abnormal fibrinogen was identified in a 10-year-old male with a mild bleeding tendency; several years later, the patient developed a thrombotic event. Fibrin polymerization of plasma from the propositus and his mother, as measured by turbidity, was impaired. Plasmin digestion of fibrinogen and thrombin bound to the clot were both normal. The structure of clots from both plasma and purified fibrinogen was characterized by permeability, scanning electron microscopy and rheological measurements. Permeability of patients' clots was abnormal, although some measurements were not reliable because the clots were not mechanically stable. Consistent with these results, the stiffness of patients' clots was decreased approximately two-fold. Electron microscopy revealed that the patients' clots were very heterogeneous in structure. DNA sequencing of the propositus and his mother revealed a new unique point mutation that gives rise to a fibrinogen molecule with a missing amino acid residue at Aalpha-Asn 80. This new mutation, which would disrupt the alpha-helical coiled-coil structure, emphasizes the importance of this part of the molecule for fibrin polymerization and clot structure. This abnormal fibrinogen has been named fibrinogen Caracas VI.  相似文献   
7.
Coronary artery disease accounts for more than half of the morbidity and mortality associated with abdominal aortic surgery. To improve the results of vascular surgery, the risk of perioperative cardiac ischemia should be evaluated in each patient. Routine coronary angiography demonstrated severe correctable coronary artery disease in 14% of patients who had no history or electrocardiographic evidence of coronary artery disease. Exercise testing before abdominal aortic aneurysm repair will identify patients at high risk of cardiac ischemia. Dipyridamole-thallium imaging will identify high-risk patients before surgery for aortoiliac occlusive disease. Some patients with symptomatic coronary disease who are at extremely high risk should undergo preoperative coronary revascularization. Others should have their vascular surgery deferred, because their cardiac risk may exceed the anticipated benefit of the vascular surgery. Patients at moderate risk may need more intensive intraoperative monitoring. Patients without evidence of cardiac ischemia with stress may undergo vascular surgery with a low risk of perioperative cardiac ischemia. Finally, patients who have evidence of ischemic heart disease should be considered for coronary revascularization following successful vascular repair in order to prolong their survival.  相似文献   
8.
Human chromosome 11p15.5 and distal mouse chromosome 7 include a megabase-scale chromosomal domain with multiple genes subject to parental imprinting. Here we describe mouse and human versions of a novel imprinted gene, IMPT1 , which lies between IPL and p57 KIP2 and which encodes a predicted multi-membrane-spanning protein similar to bacterial and eukaryotic polyspecific metabolite transporter and multi- drug resistance pumps. Mouse Impt1 and human IMPT1 mRNAs are highly expressed in tissues with metabolite transport functions, including liver, kidney, intestine, extra-embryonic membranes and placenta, and there is strongly preferential expression of the maternal allele in various mouse tissues at fetal stages. In post-natal tissues there is persistent expression, but the allelic bias attenuates. An allelic expression bias is also observed in human fetal and post-natal tissues, but there is significant interindividual variation and rare somatic allele switching. The fact that Impt1 is relatively repressed on the paternal allele, together with data from other imprinted genes, allows a statistical conclusion that the primary effect of human chromosome 11p15.5/mouse distal chromosome 7 imprinting is domain-wide relative repression of genes on the paternal homolog. Dosage regulation of the metabolite transporter gene(s) by imprinting might regulate placental and fetal growth.   相似文献   
9.
Recently, in-vitro maturation (IVM) of immature human oocytes recovered from non-stimulated follicles has been applied in the treatment of infertility. However, in previous reports, very few embryos cultured in conventional medium have reached the expanded blastocyst stage following in-vitro maturation and fertilization (IVM/IVF). The objective of this study was to investigate whether the developmental competence of human embryos following IVM/IVF could be enhanced by the use of a human ampullary cell co-culture system. Immature human oocytes were aspirated from small follicles at Caesarean section and then cultured in medium containing human menopausal gonadotrophin for 36 to 48 h, followed by insemination. Zygotes were randomly cultured either in conventional culture medium alone or in the co-culture system. Of 48 embryos cultured in conventional medium alone, all arrested at the 2-16- cell stage on day 3 after insemination. Of 46 embryos cultured in the co-culture system, 26 embryos (56.5%) arrested at the 2-16-cell stage. Six embryos (13%) developed to the morula stage. Fourteen embryos (30.4%) developed to expanded blastocysts and two blastocysts were hatching on day 7 after insemination. We conclude that co-culture significantly enhances the development of blastocysts in embryos resulting from IVM/IVF.   相似文献   
10.
Mutations in the gene encoding the Survival Motor Neuron (SMN) protein are responsible for autosomal recessive proximal spinal muscular atrophy (SMA). SMN orthologues have been identified in the nematode worm Caenorhabditis elegans and the yeast Schizosaccharomyces pombe but, to date, no human paralogues have been described. Here we describe identification and characterization of an SMN-related protein (SMNrp) gene that encodes a novel protein of 239 amino acids, which has recently been identified as a constituent of the spliceosome complex and designated SPF30. Significant similarity to the SMN protein is apparent only within a central region of SMNrp that represents a tudor domain. The SMNrp/SPF30 gene has been mapped to chromosome 10q23. It is differentially expressed, with abundant levels in skeletal muscle. An exclusively nuclear localization for SMNrp in cultured cells and muscle sections was revealed using GFP fusion constructs and thereafter confirmed with a polyclonal antibody raised against SMNrp. Overexpression of SMNrp as a fusion protein in HeLa cells in culture induced dose-dependent apoptosis with positive TUNEL staining. In addition to a possible role for this protein as a pro-apoptotic factor, SMN and its related protein share significant similarities in sequence and cellular function.   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