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   175篇
  免费   9篇
  国内免费   6篇
耳鼻咽喉   9篇
儿科学   6篇
妇产科学   2篇
基础医学   22篇
口腔科学   1篇
临床医学   19篇
内科学   28篇
神经病学   17篇
特种医学   4篇
外科学   24篇
综合类   7篇
预防医学   10篇
眼科学   1篇
药学   27篇
中国医学   3篇
肿瘤学   10篇
  2022年   11篇
  2021年   14篇
  2020年   7篇
  2019年   10篇
  2018年   12篇
  2017年   1篇
  2016年   7篇
  2015年   8篇
  2014年   7篇
  2013年   7篇
  2012年   11篇
  2011年   21篇
  2010年   11篇
  2009年   6篇
  2008年   5篇
  2007年   9篇
  2006年   8篇
  2005年   9篇
  2004年   5篇
  2003年   7篇
  2002年   4篇
  1999年   2篇
  1987年   1篇
  1986年   3篇
  1984年   2篇
  1981年   2篇
排序方式: 共有190条查询结果,搜索用时 46 毫秒
101.
102.
103.
104.
Catamenial pneumothorax: optimal hormonal and surgical management.   总被引:1,自引:0,他引:1  
OBJECTIVE: To provide further information addressing the etiology, optimal hormonal management and surgical management in catamenial pneumothorax (CP). METHODS: We retrospectively analyzed records of all female patients operated on for spontaneous pneumothorax at a university hospital between January 1993 and March 2002. RESULTS: In eight of 24 patients, pneumothoraces were timed with menses. In all, the right side was involved. Seven patients were on hormonal medications pre-operatively and six post-operatively. All six patients taking estrogen/progesterone replacement had recurrences pre-operatively and two of three had recurrences post-operatively while on these medications. No patient suffered a pneumothorax either pre- or post-operatively while taking a gonadotropin releasing hormone agonist (two and three patients, respectively). Intraoperative findings included diaphragmatic implants [5] diaphragmatic fenestrations [4], apical blebs [2] and visceral pleural implants [2]. All pathology was specifically addressed at the time of surgery. Pleural space management included mechanical pleurodesis in seven and pleurectomy with talc insufflation in 1. Follow-up ranged from 27 to 63 months with a mean of 48 months. Three patients developed post-operative recurrences. One was managed without intervention and two required additional procedures. CONCLUSION: Catamenial pneumothorax is under appreciated, representing up to one-third of women with spontaneous pneumothorax. Hormonal agents that allow for menses are ineffective. Gonadotropin releasing hormone agonists should be considered as part of the pre-operative or post-operative management in high risk patients. Our findings suggest that an additional intervention to augment pleural symphysis at the level of the diaphragm should be performed.  相似文献   
105.
Stress has been shown to be associated with altered homeostasis that may lead to oxidant-antioxidant imbalance. Non-enzymatic antioxidants are important regulators of reactive oxygen species produced in extra-cellular milieu and represent the first line of defense against them. Extra-cellular non-enzymatic antioxidants may be disturbed by the production of superoxide and nitric oxide and this has not been studied in stressful situation previously. In the present study, effects of immobilization stress (IS), both acute (IS x 1) and repeated (IS x 7) were assessed on extra-cellular total antioxidant capacity measured as plasma ferric reducing antioxidant power (FRAP) and protein sulfhydryls, and oxidative stress measured as leukocyte superoxide generation, plasma nitric oxide production (total nitrates and nitrites, NOx) and lipid peroxides in rats. Effects of pretreatment with nitric oxide synthase (NOS) inhibitors and vitamin E were also studied on these biochemical parameters. The results showed that both IS x 1 and IS x 7 resulted in extra-cellular oxidant-antioxidant imbalance as oxidant generation was increased and non-enzymatic antioxidants were depleted. Pretreatment either with NOS inhibitors or vitamin E restored stress-induced extracellular oxidant-antioxidant imbalance implying their potential role as antioxidants. Our data suggest that there is extra-cellular oxidant-antioxidant imbalance in the stressed rats, with greater magnitude of severity in repeated stress paradigm. Augmentation of antioxidant defenses might be beneficial in long-term stress.  相似文献   
106.
Buschke Lowenstein tumour or giant condyloma acuminata is a rare entity with only less then 50 cases reported in English literature so far. No such case has been reported from the Kashmir valley. They are considered as intermediate lesions between simple condyloma acuminata and invasive squamous cell carcinoma. A 57-year-old heterosexual male presented with a giant perianal condyloma. The lesion was surgically excised completely. Postoperatively patient was put on topical 5-FU ointment. Patient is recurrence free 6 months after surgery. The giant condyloma acuminate is an aggressive tumour with propensity for recurrance and malignant transformation. Surgical excision is the treatment of choice. One such rare case is discussed with review of literature.  相似文献   
107.
108.
Liquid micro-jets are crucial for sample delivery of protein crystals and other macromolecular samples in serial femtosecond crystallography. When combined with MHz repetition rate sources, such as the European X-ray free-electron laser (EuXFEL) facility, it is important that the diffraction patterns are collected before the samples are damaged. This requires extremely thin and very fast jets. In this paper we first explore numerically the influence of different nozzle orifice designs on jet parameters and finally compare our simulations with the experimental data obtained for one particular design. A gas dynamic virtual nozzle (GDVN) model, based on a mixture formulation of Newtonian, compressible, two-phase flow, is numerically solved with the finite volume method and volume of fluid approach to deal with the moving boundary between the gas and liquid phases. The goal is to maximize the jet velocity and its length while minimizing the jet thickness. The design studies incorporate differently shaped nozzle orifices, including an elongated orifice with a constant diameter and an orifice with a diverging angle. These are extensions of the nozzle geometry we investigated in our previous studies. Based on these simulations it is concluded that the extension of the constant diameter channel makes a negligible contribution to the jet’s length and its velocity. A change in the angle of the nozzle outlet orifice, however, has a significant effect on jet parameters. We find these kinds of simulation extremely useful for testing and optimizing novel nozzle designs.  相似文献   
109.
110.
Biomphalaria glabrata is an intermediate snail host for the human blood fluke Schistosoma mansoni. To survive in B. glabrata, S. mansoni must suppress the snail's haemocyte-mediated defence response; the molecular mechanisms by which this is achieved remain largely unknown. We report here that S. mansoni excretory-secretory products (ESPs) attenuate phosphorylation of extracellular signal-regulated kinase (ERK) in haemocytes from a B. glabrata strain susceptible to S. mansoni. Whole S. mansoni sporocysts also impair ERK signalling in these cells. In striking contrast, ERK signalling in haemocytes from a B. glabrata strain refractory to schistosome infection is unaffected by ESPs or sporocysts. Effects of ESPs on ERK are similar in the presence or absence of snail plasma, thus ESPs seem to affect haemocytes directly. These findings reveal novel schistosome interference mechanisms; as ERK regulates various haemocyte defence reactions, we propose that disruption of ERK signalling in haemocytes facilitates S. mansoni survival within susceptible B. glabrata.  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