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   3239篇
  免费   313篇
  国内免费   217篇
耳鼻咽喉   27篇
儿科学   34篇
妇产科学   48篇
基础医学   108篇
口腔科学   25篇
临床医学   301篇
内科学   705篇
皮肤病学   17篇
神经病学   129篇
特种医学   139篇
外科学   408篇
综合类   529篇
现状与发展   1篇
预防医学   205篇
眼科学   46篇
药学   385篇
  16篇
中国医学   542篇
肿瘤学   104篇
  2024年   11篇
  2023年   72篇
  2022年   131篇
  2021年   234篇
  2020年   186篇
  2019年   177篇
  2018年   153篇
  2017年   120篇
  2016年   128篇
  2015年   97篇
  2014年   217篇
  2013年   218篇
  2012年   203篇
  2011年   239篇
  2010年   221篇
  2009年   185篇
  2008年   199篇
  2007年   127篇
  2006年   127篇
  2005年   98篇
  2004年   67篇
  2003年   95篇
  2002年   47篇
  2001年   42篇
  2000年   43篇
  1999年   44篇
  1998年   31篇
  1997年   32篇
  1996年   27篇
  1995年   27篇
  1994年   15篇
  1993年   14篇
  1992年   18篇
  1991年   17篇
  1990年   22篇
  1989年   17篇
  1988年   8篇
  1987年   5篇
  1986年   10篇
  1985年   7篇
  1984年   8篇
  1983年   5篇
  1982年   3篇
  1981年   4篇
  1980年   2篇
  1979年   5篇
  1978年   3篇
  1977年   2篇
  1976年   4篇
  1971年   2篇
排序方式: 共有3769条查询结果,搜索用时 343 毫秒
1.
ObjectivesTo explore the relationships among potentially modifiable factors related to childbirth and effective breastfeeding initiation at approximately 36 hours after birth and duration and exclusivity at hospital discharge, 2 weeks, 2 months, and 6 months after birth in primiparous women and to explore whether modifiable and nonmodifiable secondary factors and covariates influenced the relationships among factors related to childbirth and these breastfeeding outcomes.DesignA prospective, longitudinal, cohort study.SettingThe postpartum units of two general hospitals in eastern Canada.ParticipantsNinety-seven mother–infant dyads.MethodsWe recorded demographic, childbirth, obstetric history, and breastfeeding data through chart review. A breastfeeding observation was completed at approximately 36 hours after birth by unit nurses. Participants maintained breastfeeding logs in hospital and for 6 months after birth and completed three self-report questionnaires before discharge. We analyzed outcomes using backward stepwise linear and logistic regression.ResultsOne childbirth factor, labor induced with oxytocin, was negatively associated with effective initiation of breastfeeding, and none was related to breastfeeding duration and exclusivity at any time point. Maternal weight; professional support; and newborn’s gestational age at birth, 5-minute Apgar score, weight loss, LATCH score, and active feeds (newborn actively suckled at the breast) were significantly associated with breastfeeding outcomes.ConclusionInduction of labor with oxytocin should be used judiciously; when used, nurses must be hypervigilant to assess the mother–infant dyad for breastfeeding issues and to intervene to prevent or remediate them.  相似文献   
2.
随着腔镜技术的进一步发展以及微创理念应用于结直肠外科疾病的诊治中,结直肠相关疾病的诊治发生了翻天覆地的变化。由传统的经腹手术到腹腔镜手术、经自然腔道手术,再到经自然腔道取标本手术(NOSES),结直肠疾病的外科诊治在微创领域取得了巨大成果。NOSES技术是目前结直肠外科在微创领域前沿的手术方式之一,它通过经直肠、阴道取标本来避免了腹壁的辅助取标本切口,从而将结直肠外科手术进一步微创化。NOSES技术集传统腹腔镜手术的优势与现代微创外科的理念于一体,它在确保手术效果的基础上集中体现了微创、加速康复外科、功能外科、"无疤"等理念的特点。本文主要就国内外各中心开展NOSES技术在结直肠外科诊治开展中的相关经验、心得和体会进行综述。  相似文献   
3.
4.
5.
Fast CT-PRESS-based spiral chemical shift imaging at 3 Tesla.   总被引:2,自引:0,他引:2  
A new sequence is presented that combines constant-time point-resolved spectroscopy (CT-PRESS) with fast spiral chemical shift imaging. It allows the acquisition of multivoxel spectra without line splitting with a minimum total measurement time of less than 5 min for a field of view of 24 cm and a nominal 1.5x1.5-cm2 in-plane resolution. Measurements were performed with 17 CS encoding steps in t1 (Deltat1=12.8 ms) and an average echo time of 151 ms, which was determined by simulating the CT-PRESS experiment for the spin systems of glutamate (Glu) and myo-inositol (mI). Signals from N-acetyl-aspartate, total creatine, choline-containing compounds (Cho), Glu, and mI were detected in a healthy volunteer with no or only minor baseline distortions within 14 min on a 3 T MR scanner.  相似文献   
6.
分瓶法测定果蝇吸入麻醉药半数麻醉有效浓度   总被引:2,自引:1,他引:1  
目的 建立测定果蝇吸入麻醉药半数麻醉有效浓度 (ED50 )的方法学。方法 在 11个 32 5ml的三角烧瓶中各放入 30只雄性果蝇 ,分别加入不同容量的异氟醚标准气 ,使 11个烧瓶中异氟醚浓度分布在零效应浓度与百分之百效应浓度之间。以果蝇失去附壁及运动能力为标准计算各瓶中被麻醉果蝇数 ,用正规法计算出ED50 。结果  11次实验在 2 5及 5 0min时的量 -效关系曲线均呈S形 ,用各自的对数浓度与概率单位作图都呈直线相关 ,相关系数分别为 0 .972± 0 .0 14和 0 .971± 0 .0 2 5 ,ED50 值分别为 (0 .5 1± 0 .0 6 8) %和 (0 .4 7± 0 .0 85 ) % ,变异系数分别为 13.3%和 18.0 %。结论 本法稳定性较好 ,实用可行  相似文献   
7.
Minilaparoscopy-assisted natural orifice surgery.   总被引:5,自引:0,他引:5  
BACKGROUND AND OBJECTIVES: New technology has allowed us to perform major abdominal and pelvic surgeries with increasingly smaller instruments. The ultimate goal is surgery with no visible scars. Until current technical limitations are overcome, minilaparoscopy-assisted natural orifice surgery (MANOS) provides a solution. The aim of this study was to examine our clinical and experimental experience with MANOS. METHOD: Minilaparoscopic abdominal instruments were used together with a large vaginal port, which was used for insufflation, visual purposes, introduction of operative instruments, and specimen extraction. Minilaparoscopy-assisted intraperitoneal transgastric appendectomy was done in simulators (Lap trainer with SimuVision, Simulab Corp., Seattle, WA). RESULTS: Since 1998, we have used this technique in 100 cases including ovarian cystectomies, oophorectomies, salpingo-oophorectomies, myomectomies, appendectomies, and cholecystectomies. Some oophorectomies were performed after vaginal hysterectomy in cases where vaginal extraction was not possible. In this case series, we had only one complication, a case of postoperative fever after an ovarian cystectomy, which was diagnosed as drug-related fever. Our limited simulator experience showed that MANOS is a feasible technique for performing transgastric appendectomies. CONCLUSION: It may take several years for natural orifice surgery to become standard care. Meanwhile, MANOS could encourage and expedite this process.  相似文献   
8.
清开灵注射液治疗脑血管性痴呆32例   总被引:9,自引:0,他引:9  
目的观察清开灵注射液治疗脑血管性痴呆的疗效.方法将中医学辨证属于实证的64例脑血管性痴呆患者随机分为治疗组(清开灵注射液组)和对照组(脑复康组),治疗5周后,将两组治疗前后在智力障碍程度、肢体功能、血液流变学指标、中医证型疗效方面的变化进行比较.结果经治疗后治疗组和对照组相比较,智力障碍程度变化(有效率、MMSE、ADL积分)、肌力、步行能力改变有显著性差异,p<0.05.而治疗前后组内及组间血流变指标虽有一定下降,但无统计学意义(p>0.05).结论清开灵注射液对脑血管性痴呆患者,在改善智力障碍、肌力、步行能力方面有较好的疗效.  相似文献   
9.
甲状腺素治疗新生儿硬肿症疗效观察   总被引:1,自引:0,他引:1  
目的 观察甲状腺素治疗新生儿硬肿症的疗效。方法 将63例随机分为甲状腺素治疗组(简称治疗组)32例,对照组31例,两组均给予综合治疗,治疗组加用甲状腺素片每天4~6mg/kg口服,疗程1周。结果 治疗组与对照组总有效率分别为87.5%、61.3%,有显著差异(P<0.05)。两组间复温时间分别为7.0±3.7h、16.5±11.2h,硬肿消退时间分别为4.1±1.9天、6.9±3.1天,住院时间分别为6.9±3.1天、9.8±4.6天,治疗组比对照组明显缩短,有显著差异(P<0.01)。结论 新生儿硬肿症使用甲状腺素治疗可明显提高治愈率,缩短病程,且使用方便,无副作用。  相似文献   
10.
After removal of intraductal stones, a 10‐Fr or 7‐Fr pancreatic stent was placed in 16 patients with upstream ductal dilation proximal to a stricture of the main pancreatic duct. Stents were removed after a mean duration of 52.5 days. Nine patients underwent repeated stenting. About one year after removal of the initial stent, when the remaining upstream ductal dilation was found on follow‐up pancreatograms, the next stent was replaced. Repeated stenting improved outflow of pancreatic juice more effectively than one‐time stenting. Correlation between long‐term pain relief without recurrence of intraductal stones and reduction of duct diameter was also shown. Stent occlusion was observed in 14 of 30 stents. Stent occlusion was frequently associated with recurrence of pancreatitis and intraductal stones, and was also associated with morphologic changes in the pancreatic ductal system. Although there were no significant differences between stent patency of the initial stents and that of the next stents, stent patency of 10‐Fr stents was superior to that of 7‐Fr stents. 10‐Fr stents should be removed within 8 weeks and 7‐Fr stents should be removed within 4 weeks for the prevention of stent occlusion. Repeated stenting with short‐term stenting is therefore considered a safe and effective protocol of endoscopic pancreatic stenting.  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