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   458篇
  免费   37篇
  国内免费   8篇
耳鼻咽喉   4篇
儿科学   23篇
妇产科学   12篇
基础医学   62篇
口腔科学   2篇
临床医学   38篇
内科学   108篇
皮肤病学   4篇
神经病学   81篇
特种医学   19篇
外科学   31篇
预防医学   19篇
眼科学   2篇
药学   42篇
中国医学   1篇
肿瘤学   55篇
  2023年   3篇
  2022年   18篇
  2021年   10篇
  2020年   10篇
  2019年   21篇
  2018年   9篇
  2017年   7篇
  2016年   10篇
  2015年   16篇
  2014年   15篇
  2013年   19篇
  2012年   26篇
  2011年   33篇
  2010年   26篇
  2009年   15篇
  2008年   27篇
  2007年   26篇
  2006年   29篇
  2005年   26篇
  2004年   22篇
  2003年   16篇
  2002年   17篇
  2001年   7篇
  2000年   10篇
  1999年   11篇
  1998年   3篇
  1997年   3篇
  1996年   2篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   5篇
  1991年   8篇
  1990年   5篇
  1989年   4篇
  1988年   2篇
  1987年   5篇
  1986年   9篇
  1985年   6篇
  1984年   4篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1979年   2篇
  1978年   1篇
  1975年   1篇
  1973年   1篇
  1972年   1篇
  1971年   4篇
  1969年   1篇
排序方式: 共有503条查询结果,搜索用时 46 毫秒
1.
2.
Cancer predisposition syndromes (CPS) result from germline pathogenic variants, and they are increasingly recognized in the etiology of many pediatric cancers. Herein, we report the genetic/genomic analysis of 40 pediatric patients enrolled from 2016 to 2018. Our diagnostic workflow was successful in 50% of screened cases. Overall, the proportion of CPS in our case series is 10.9% (20/184) of enrolled patients. Interestingly, 12.5% of patients achieved a conclusive diagnosis through the analysis of chromosomal imbalance. Indeed, we observed germline microdeletions/duplications of regions encompassing cancer-related genes in 50% of patients undergoing array-CGH: EIF3H duplication in a patient with infantile desmoplastic astrocytoma and low-grade Glioma; SLFN11 deletion, SOX4 duplication, and PARK2 partial deletion in three neuroblastoma patients; a PTPRD partial deletion in a child diagnosed with glioblastoma multiforme. Finally, we identified two cases due to DICER1 germline mutations.  相似文献   
3.
The new second-generation cephalosporins, cefonicid, ceforanide, and cefuroxime, have recently become available. These agents are generally less active against gram-positive cocci than first-generation cephalosporins and, at best, equal to cefoxitin and cefamandole against many gram-negative bacteria. Cefuroxime, however, is the most active cephalosporin for beta-lactamase-producing Haemophilus influenzae. These newer agents have superior pharmacokinetic characteristics over cefoxitin and cefamandole. Smaller doses, longer dosing intervals and, potentially, a reduction in total drug cost may be the real advantage of these agents. Open trials and a limited number of comparative studies have documented the effectiveness of cefonicid, ceforanide, and cefuroxime in the treatment of most mild-to-serious infectious diseases, although failures with cefonicid in the treatment of staphylococcal infections have been reported. Notably, cefuroxime has received approval for the treatment of common pediatric bacterial meningitis infections. Replacement of cefamandole or cefoxitin with one of these "longer-acting" agents may be cost-beneficial; however, clinicians must be on alert for the development of bacterial resistance or decreased efficacy.  相似文献   
4.
STUDY DESIGN: A case report. OBJECTIVES: To report and discuss a case of post-traumatic epidural hematoma of the craniocervical junction with concomitant brain stem infarction. SUMMARY OF BACKGROUND DATA: Post-traumatic epidural hematoma of the cervical spine and brain stem post-traumatic infarction are very rare disorders. Post-traumatic epidural hematoma is usually located dorsally in the epidural space. METHODS: The clinical, neuroradiologic, and neurophysiologic findings in one patient with post-traumatic epidural hematoma located ventrally at the cervicomedullary junction and associated with medial infarction at the pontomedullary junction are reported. RESULTS: The main clinical finding in this patient was bilateral corticospinal and corticobulbar tract involvement. A magnetic resonance image showed displacement and flattening of the medulla oblongata and of the most cranial portion of cervical cord, which were caused by the epidural hematoma associated with an ischemic lesion of the pontomedullary junction. Results of central motor conduction studies indicated that the abnormality of the central motor pathways was localized at brain stem level, and that there was normal conduction from the cervicomedullary junction to spinal cord. CONCLUSION: This is the first reported case of spinal epidural hematoma located ventrally in the cervical spine at the cervicomedullary junction level and concomitant infarction at the pontomedullary junction resulting from whiplash injury.  相似文献   
5.
The assay for trp5 gene conversion and ilv1‐92 reversion in Saccharomyces cerevisiae strain D7 was used to characterize the induction of an adaptive response by hydrogen peroxide (H2O2). Effects of a small priming dose on the genotoxic effects of a larger challenge dose were measured in exponential cultures and in early stationary phase. An adaptive response, indicated by smaller convertant and revertant frequencies after the priming dose, occurred at lower priming and challenge doses in young, well‐aerated cultures. Closely spaced priming doses from 0.000975 to 2 mM, followed by a 1 mM challenge, showed that the induction of the adaptive response is biphasic. In exponential cultures it was maximal with a priming dose of 0.125–0.25 mM. Very small priming doses were insufficient to induce the adaptive response, whereas higher doses contributed to damage. A significant adaptive response was detected when the challenge dose was administered 10–20 min after the priming exposure. It was fully expressed within 45 min, and the yeast began to return to the nonadapted state after 4–6 hr. Because of the similarity of the biphasic induction to hormetic curves and the proposal that adaptive responses are a manifestation of hormesis, we evaluated whether the low doses of H2O2 that induce the adaptive response show a clear hormetic response without a subsequent challenge dose. Hormesis was not evident, but there was an apparent threshold for genotoxicity at or slightly below 0.125 mM. The results are discussed with respect to linear, threshold, and hormesis dose–response models. Environ. Mol. Mutagen. 54:384–396, 2013. © 2013 Wiley Periodicals, Inc.  相似文献   
6.
Hereditary stomatocytoses are a wide class of hemolytic anemias characterized by alterations of ionic flux with increased cation permeability that results in inappropriate shrinkage or swelling of the erythrocytes, and water lost or gained osmotically. The last few years have been crucial for new acquisitions in this field in terms of identifying new causative genes and of studying their pathogenetic mechanisms. This review summarizes the main features of erythrocyte membrane transport diseases, dividing them into forms with either isolated erythroid phenotype (nonsyndromic) or extra‐hematological manifestations (syndromic), and focusing particularly on the most recent advances regarding dehydrated forms of hereditary stomatocytosis and familial pseudohyperkalemia.  相似文献   
7.
8.
9.
10.
Annals of Nuclear Medicine - Radical cystectomy with permanent urinary diversion is the gold standard treatment for invasive muscle bladder cancer. Hydronephrosis is common in these patients, but...  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