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   817篇
  免费   46篇
  国内免费   5篇
耳鼻咽喉   7篇
儿科学   27篇
妇产科学   7篇
基础医学   61篇
口腔科学   21篇
临床医学   109篇
内科学   153篇
皮肤病学   22篇
神经病学   19篇
特种医学   97篇
外科学   135篇
综合类   69篇
预防医学   68篇
眼科学   2篇
药学   32篇
  1篇
中国医学   19篇
肿瘤学   19篇
  2022年   6篇
  2021年   11篇
  2020年   13篇
  2019年   12篇
  2018年   16篇
  2017年   7篇
  2016年   8篇
  2015年   30篇
  2014年   33篇
  2013年   31篇
  2012年   40篇
  2011年   41篇
  2010年   48篇
  2009年   34篇
  2008年   42篇
  2007年   42篇
  2006年   30篇
  2005年   23篇
  2004年   18篇
  2003年   17篇
  2002年   14篇
  2001年   21篇
  2000年   14篇
  1999年   9篇
  1998年   27篇
  1997年   26篇
  1996年   33篇
  1995年   23篇
  1994年   24篇
  1993年   14篇
  1992年   4篇
  1990年   3篇
  1989年   15篇
  1988年   16篇
  1987年   12篇
  1986年   10篇
  1985年   13篇
  1984年   12篇
  1983年   6篇
  1982年   9篇
  1981年   4篇
  1980年   10篇
  1979年   3篇
  1978年   4篇
  1977年   3篇
  1976年   9篇
  1975年   7篇
  1970年   4篇
  1969年   3篇
  1968年   4篇
排序方式: 共有868条查询结果,搜索用时 15 毫秒
861.
汤青芳 《临床医学工程》2014,(10):1295-1296
目的探讨术前预防性使用抗生素对剖宫产术后切口感染的影响。方法以2012年1月至2014年1月间我院收治的106例剖宫产孕妇为研究对象,随机分为术前应用抗生素组(观察组)及术后应用抗生素组(对照组)各53例。比较两组患者术中出血量、术后体温及血液学检查结果,观察患者术后感染情况。结果观察组术中出血量为165.4 mL,对照组为159.2 mL,两组之间差异无统计学意义(P>0.05);观察组甲级愈合率为96.2%,对照组甲级愈合率为90.6%,两组之间差异有统计学意义(P<0.05);观察组术后最高体温>38℃者4例、对照组术后最高体温>38℃者7例,两组之间差异无统计学意义(P>0.05);观察组C反应蛋白异常升高者2例,对照组术后C反应蛋白异常升高者9例,两组之间差异有统计学意义(P<0.05);观察组术后腹部切口感染、产褥感染例数分别为1例和1例,对照组术后腹部切口感染、产褥感染例数分别为5例和3例,两组之间差异有统计学意义(P<0.05);两组术后各有1例泌尿系统感染病例,差异无统计学意义(P>0.05)。结论术前预防性使用抗生素降低患者术后切口感染的发生,有利于切口愈合。  相似文献   
862.
随着凋亡相关研究的进展,心肌细胞凋亡与心肌梗死(acute myocardial infarction,AMI)的关系逐渐受到重视.本实验联合应用粒细胞集落刺激因子(granulocyte-colony stimu-lating factor,G-CSF)和辛伐他汀动员干细胞修复AMI后的梗死心肌,通过流式及免疫组化法检测细胞凋亡率和BCL-2/BAX比值,评价其干细胞动员作用对梗死后心肌细胞凋亡的影响.  相似文献   
863.
Background Climate therapy (heliotherapy) of psoriasis is an effective and natural treatment. Ultraviolet radiation (UVB) from the sun improves psoriasis and induces vitamin D3 synthesis. Objective The aim of the study was to investigate the effect of climate therapy on vitamin D3 synthesis, blood glucose, lipids and vitamin B12 in psoriasis patients. Methods Twenty Caucasian patients (6 women and 14 men; mean age, 47.2 years; range, 24–65) with moderate to severe psoriasis [mean Psoriasis Area and Severity Index (PASI) score 9.8; range, 3.8–18.8] received climate therapy at the Gran Canarias for 3 weeks. Blood samples were drawn before and after 15 days of sun exposure. In addition, the patients’ individual skin UV doses based on UV measurements were estimated. Results Sun exposure for 15 days lead to a 72.8% (± 18.0 SD) reduction in the PASI score in psoriasis patients. Although no direct correlation was observed between PASI score improvement and UVB dose, the sun exposure improved the vitamin D, lipid and carbohydrate status of the patients. The serum concentrations of 25‐hydroxyvitamin D [25(OH)D] increased from 57.2 ± 14.9 nmol/L before therapy to 104.5 ± 15.8 nmol/L (P < 0.0001) after 15 days of sun exposure; the serum levels of 1,25‐dihydroxyvitamin D [1,25(OH)2D] increased from 146.5 ± 42.0 to 182.7 ± 59.1 pmol/L (P = 0.01); the ratio of low‐density lipoprotein cholesterol and high‐density lipoprotein cholesterol decreased from 2.4 to 1.9 (P < 0.001); and the haemoglobin A1c (HbA1c) levels decreased from 5.6 ± 1.7% to 5.1 ± 0.3% (P < 0.0001). Conclusion Climate therapy with sun exposure had a positive effect on psoriasis, vitamin D production, lipid and carbohydrate status.  相似文献   
864.
865.
The regulatory function of recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) on granulocyte production in vivo was evaluated in an autologous bone marrow transplantation model using rhesus monkeys. Monkeys were exposed to 9.0 Gy total body irradiation and then transplanted with 5.0 x 10(7) low-density bone marrow cells/kg. Alzet miniosmotic pumps were subcutaneously implanted to deliver rhGM-CSF at a rate of 50,400 U/kg/d. Minipumps, containing either rhGM-CSF or saline, were implanted between zero and five days after transplantation for seven days. Kinetic recoveries of peripheral blood cells after either saline or rhGM-CSF treatment were compared. Treatment with rhGM-CSF accelerated the recovery of neutrophils. Neutrophils in rhGM-CSF-treated animals recovered to 80% (3.4 x 10(3)/mm3) pre-irradiation control levels by day 20, in comparison with only 33% (0.9 x 10(3)/mm3) recovery for saline control monkeys. In addition, the recovery of neutrophils was enhanced over that of the controls, reaching 140% v 70% on day 30. Another prominent feature of rhGM-CSF-treated monkeys was the accelerated recovery of platelets, reaching near 50% normal levels by day 24 in comparison with 20% of normal levels for controls. The infusion of rhGM-CSF was shown to be an effective regulator of early hematopoietic regeneration, leading to the accelerated recovery of both neutrophils and platelets and then providing a consistent sustained increase of neutrophils even in the absence of rhGM-CSF.  相似文献   
866.
ASL在中枢神经系统疾病诊断中的初步应用体会   总被引:3,自引:0,他引:3       下载免费PDF全文
目的:探讨动脉自旋标记(ASL)MRI灌注成像技术在中枢神经系统疾病中的临床价值.方法:24例颅内病变患者,其中急性脑梗死2例,脑血管畸形7例,胶质瘤4例,淋巴瘤2例,转移瘤4例,脑膜瘤5例.所有病例均经手术病理或随访证实.用ASL技术和动态磁敏感对比成像(DSC)2种方法进行MR灌注成像,分析2种方法对颅内病变的诊断价值.结果:对急性脑梗死患者可以显示灌注缺损区或低灌注区.在评价肿瘤血供方面,ASL与DSC 2种方法所测肿瘤组织rCBF值比较,差异无显著性意义.ASL技术磁敏感伪影明显小于DSC法,对于有出血、钙化的病灶以及颅底病变的显示明显优于DSC法,提高了定量分析的准确性.结论:ASL技术在评价脑组织局部血流灌注方面,具有可重复性高、完全非侵入性、不用注射对比剂等优点.同时对于有出血、钙化或位于颅底的病变,ASL技术明显优于DSC法.  相似文献   
867.
868.
Cryopreservation of single human spermatozoa   总被引:6,自引:5,他引:6  
A procedure is described that allows cryopreservation and efficient post-thaw recovery of either a single or a small group of human spermatozoa. This is achieved by injecting them into cell-free human, mouse or hamster zonae pellucidae before the addition of cryoprotectant. The method involves a combination of physical micromanipulation procedures and glycerol-mediated cryoprotection. Zonae were tracked by positioning them in straws between two small air bubbles prior to freezing. Spermatozoa from poor specimens were cryopreserved and their fertilizing ability after thawing was compared with that of fresh spermatozoa from fertile men. Human eggs used for fertilization testing were either 1 day old or in-vitro matured. Only 2% of the frozen zonae were lost and >75% of spermatozoa cryopreserved in this manner were recovered and prepared for intracytoplasmic sperm injection. The feasibility of cryopreserving a single spermatozoon was assessed. Fifteen motile spermatozoa were frozen in 15 zonae, of which 14 were recovered after thawing. Ten were injected into spare eggs, of which eight became fertilized. Spermatozoa recovered mechanically from human zonae fertilized the same proportion of oocytes as fresh fertile control spermatozoa. The recovery and fertilization rates with spermatozoa frozen in animal zonae were 87 and 78% respectively. The fertilization rate was marginally higher (P < 0.05) than that for spermatozoa frozen in human zonae, perhaps because the latter may have acrosome reacted more frequently. The zona pellucida appears to be an ideally suited sterile vehicle for storage of single spermatozoa.   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