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   4449篇
  免费   254篇
  国内免费   6篇
耳鼻咽喉   35篇
儿科学   153篇
妇产科学   65篇
基础医学   577篇
口腔科学   89篇
临床医学   852篇
内科学   794篇
皮肤病学   35篇
神经病学   406篇
特种医学   129篇
外科学   333篇
综合类   55篇
一般理论   23篇
预防医学   614篇
眼科学   61篇
药学   209篇
  1篇
中国医学   4篇
肿瘤学   274篇
  2023年   16篇
  2022年   20篇
  2021年   103篇
  2020年   58篇
  2019年   91篇
  2018年   112篇
  2017年   100篇
  2016年   52篇
  2015年   91篇
  2014年   125篇
  2013年   244篇
  2012年   309篇
  2011年   326篇
  2010年   214篇
  2009年   166篇
  2008年   286篇
  2007年   315篇
  2006年   307篇
  2005年   325篇
  2004年   303篇
  2003年   263篇
  2002年   254篇
  2001年   34篇
  2000年   36篇
  1999年   28篇
  1998年   56篇
  1997年   44篇
  1996年   30篇
  1995年   43篇
  1994年   27篇
  1993年   27篇
  1992年   27篇
  1991年   21篇
  1990年   20篇
  1989年   18篇
  1988年   14篇
  1987年   21篇
  1986年   18篇
  1985年   17篇
  1984年   18篇
  1983年   18篇
  1982年   19篇
  1981年   20篇
  1980年   14篇
  1979年   12篇
  1978年   7篇
  1977年   8篇
  1976年   8篇
  1974年   6篇
  1973年   4篇
排序方式: 共有4709条查询结果,搜索用时 15 毫秒
1.
2.
This randomized controlled trial evaluated the effect of a 5-week daily skin-to-skin contact (SSC) intervention between mothers and their full-term infants, compared with care-as-usual, on exclusive and continued breastfeeding duration during the first post-natal year. Healthy pregnant women (n = 116) from a community sample were enrolled and randomly allocated to the SSC or care-as-usual condition. SSC mothers were requested to provide one daily hour of SSC for the first five post-natal weeks. Twelve months post-partum, mothers indicated the number of exclusive and continued breastfeeding months. Multiple regression analyses were conducted using intention-to-treat, per-protocol and exploratory dose–response frameworks. In intention-to-treat analyses, exclusive and continued breastfeeding duration was not different between groups (exclusive: 3.61 ± 1.99 vs. 3.16 ± 1.77 months; adjusted mean difference 0.28, 95% confidence interval [CI] ?0.33 to 0.89; p = 0.36; continued: 7.98 ± 4.20 vs. 6.75 ± 4.06 months; adjusted mean difference 0.81, 95% CI ?0.46 to 2.08; p = 0.21). In per-protocol analyses, exclusive and continued breastfeeding duration was longer for SSC than care-as-usual dyads (exclusive: 4.89 ± 1.26 vs. 3.25 ± 1.80 months; adjusted mean difference 1.28, 95% CI 0.31–2.24; p = 0.01; continued: 10.81 ± 1.97 vs. 6.98 ± 4.08 months; adjusted mean difference 2.33, 95% CI 0.13–4.54; p = 0.04). Exploratory dose–response effects indicated that more SSC hours predicted longer exclusive and continued breastfeeding duration. This study demonstrates that for the total group, the 5-week daily SSC intervention did not extend exclusive and continued breastfeeding duration. However, for mothers performing a regular daily hour of SSC, this simple and accessible intervention may extend exclusive and continued breastfeeding duration by months. Future studies are required to confirm these promising findings. Trial registration: Netherlands Trial Register (NTR5697).  相似文献   
3.
4.
Abortion is not legal in Chile even to save the woman's life or health. This situation creates serious dilemmas and vulnerabilities for both women and medical practitioners. Abortion incidence has probably decreased since 1990, when data were last studied, due to increased use of contraception and lower fertility, and deaths and complication rates have fallen as well. Misoprostol is available, but Chilean hospitals are still using D&C for incomplete abortions. Although Chilean medical professionals should by law report illegal abortions to the authorities, less than 1% of women in hospital with abortion complications are reported. There are two loopholes, one legal, one clinical. "Interruption of pregnancy" after 22 weeks of pregnancy is legal for medical reasons; this may save some women's lives but can also force prolongation of health-threatening pregnancies. Catholic clinical guidelines define interventions solely aimed at saving the woman's life, even if the fetus dies, not as abortion but "indirect abortion" and permissible. Since 1989, three bills to liberalise the law on therapeutic grounds have been unsuccessful. The political climate is not favourable to changing the law. Conservatives have also not succeeded in making the law more punitive, while the governing centre-left coalition is divided and the associated political risks are considerable.  相似文献   
5.
Wound assessment is a key element of effective wound care, and assessment of pressure ulcers includes accurate determination of wound stage. Although the original staging system established by Shea was based on his understanding of the pathology involved in pressure ulcer development, subsequent staging systems (and the one currently in use) were intended simply to establish the level of tissue damage. Recently, clinicians have drawn attention to numerous limitations associated with the current staging system, including the inability to differentiate between an inflammatory response involving intact skin and a deep tissue injury (deep bruising) underneath intact skin. This is a clinically significant difference because clinicians have noted that most inflammatory responses resolve with intervention, whereas most areas of deep tissue injury progress to full-thickness ulcers even when appropriate intervention is provided. A second area of controversy involves partial-thickness (Stage 2) lesions; because many of these lesions are caused by maceration and/or friction (as opposed to pressure) clinicians are frequently unclear regarding which of these lesions should be staged. In response to these concerns, the National Pressure Ulcer Advisory Panel convened a consensus forum and published white papers to clearly outline the issues; they solicited clinician feedback on the white papers and the Wound, Ostomy, Continence Nurses Society provided a written response. This article summarizes the key points of the white papers, WOCN Society response, and consensus forum discussion.  相似文献   
6.
7.
Objective: To determine the effect of indwelling versus intermittent feeding tube placement on weight gain, apnea, and bradycardia in premature neonates.
Design: Eligible subjects were assigned randomly to either feeding tube method. Each subject was followed for 6 days.
Setting: The study was conducted in a secondary level neonatal intensive-care unit (NICU), a tertiary level NICU in a perinatal center, and a tertiary level NICU in a referral center.
Patients/Participants: Neonates who were 24–34 weeks gestational age, developmentally appropriate for gestational age, medically stable, on full enteral feedings through an orogastric or a nasogastric tube, and not fluid restricted. Ninety-three neonates were enrolled-49 in the indwelling group and 44 in the intermittent group. Nine neonates did not complete the study.
Interventions: Nasogastric indwelling feeding tubes were placed and left in site for up to 3 days. Orogastric intermittent feeding tubes were placed for each feeding and removed at completion of the feeding.
Main outcome measures: Weight gain, apnea, and bradycardia. Results: Members of both groups had similar demographic characteristics, clinical problems, and nutritional intake. No statistical differences were found between the two groups in weight gain or episodes of apnea and bradycardia.
Conclusions: There were no statistically or clinically significant differences between the two groups. The intermittent method of feeding is more expensive. Because no clinical differences were found, the type of tube placement chosen for feeding the premature infant may be based on economics.  相似文献   
8.
9.
BACKGROUND: Somatosensory evoked potentials (SSEPs) have long been recognized as an excellent tool for detecting neural and vascular compromise during vascular, neurosurgical and orthopedic procedures. SSEPs have the ability to localize, central versus peripheral, the area of compromise. Many surgeons use only lower-limb SSEP monitoring when performing lumbar spinal surgery. The upper extremities are usually not monitored during such procedures, and monitoring oxygen saturation does not detect neural compromise. PURPOSE: To report that the expanded use of SSEP monitoring during surgery can be beneficial in detecting peripheral ischemia or neural compromise resulting from positioning. STUDY DESIGN: Three case reviews of orthopedic spine surgeries where SSEP monitoring provided early warnings of vascular and neural compression. METHODS: The cases review three different lumbar procedures in which evidence of peripheral ischemia and nerve compression were detected by SSEP monitoring. RESULTS: By the use of upper- and lower-extremity monitoring during lumbar procedures, early detection of ischemia and nerve compression were noted intraoperatively. These changes prompted examination of the patient and repositioning to correct the ischemia or compression. The repositioning in these cases corrected the problem, and no lasting effects were found. CONCLUSIONS: Including SSEP monitoring of the bilateral upper extremities should be considered during lumbar spinal procedures. Such monitoring can be offered for a slightly increased expense and only minimal time delay to place the additional required electrodes by the technician. As a direct result of the early warning of the SSEP monitoring, we were able to avoid potential ischemic injuries and improve patient outcomes.  相似文献   
10.
Information-processing theories of the orienting reflex (OR) predict that disruptions of attention which impede the registration of a stimulus in memory should retard habituation of the OR. Studies examining effects of selective inattention upon rate of habituation of skin conductance responses (SCRs) to concurrently presented stimuli have yielded inconsistent results. We employed a dichotic vigilance task calling for selective attention to either male-voice or female-voice words. Comparisons between previously attended versus nonattended stimuli were subsequently conducted for habituation of SCR, as well as for a direct measure of recognition memory. Although there were unequivocal differences in long-term memory between attended and non-attended material, there was no clear evidence for corresponding differences in either initial magnitude or rate of habituation of SCR. These data, which replicated results from an earlier study, failed to demonstrate an effect of memory on the OR as predicted by information-processing theories.  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