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   448篇
  免费   25篇
耳鼻咽喉   5篇
儿科学   9篇
妇产科学   7篇
基础医学   41篇
口腔科学   13篇
临床医学   99篇
内科学   57篇
皮肤病学   2篇
神经病学   47篇
特种医学   11篇
外科学   51篇
综合类   8篇
预防医学   53篇
眼科学   15篇
药学   29篇
中国医学   4篇
肿瘤学   22篇
  2024年   1篇
  2023年   8篇
  2022年   3篇
  2021年   10篇
  2020年   13篇
  2019年   15篇
  2018年   15篇
  2017年   13篇
  2016年   16篇
  2015年   11篇
  2014年   11篇
  2013年   27篇
  2012年   41篇
  2011年   31篇
  2010年   18篇
  2009年   16篇
  2008年   33篇
  2007年   33篇
  2006年   27篇
  2005年   27篇
  2004年   23篇
  2003年   18篇
  2002年   19篇
  2001年   8篇
  1999年   1篇
  1998年   1篇
  1997年   2篇
  1996年   1篇
  1995年   3篇
  1994年   1篇
  1993年   4篇
  1992年   3篇
  1989年   3篇
  1987年   1篇
  1986年   3篇
  1985年   1篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1981年   4篇
  1980年   2篇
  1976年   1篇
排序方式: 共有473条查询结果,搜索用时 93 毫秒
41.
Interpreters play a crucial role in many investigative interviews with child complainants of sexual abuse; however, little has been written about the interpreting process from the perspective of the interviewers. This study elicited interviewers’ perspectives about the challenges of using interpreters, with the aim of understanding how investigative interviews could be improved. The participants consisted of 21 investigative interviewers and prosecutors of child abuse cases (from a range of jurisdictions) who use interpreters on a regular basis. Thematic analysis of semi-structured interviews with the professionals about the interpreting process revealed two main challenges particular to child abuse interviews, namely the interpreters’ lack of preparedness to deal with the traumatic and sensitive nature of children's abuse histories, and an insufficient understanding of ‘best-practice’ child interview process. The recommendations focus on the need for more specialised training for, and screening of, interpreters, and more extensive use of pre-conferencing to familiarise children with the interpreter-mediated interview process.  相似文献   
42.
The active form of vitamin D, 1alpha,25-dihydroxyvitamin D [1alpha,25(OH)2D], is synthesized from its precursor 25 hydroxyvitamin D [25(OH)D] via the catalytic action of the 25(OH)D-1alpha-hydroxylase [1alpha(OH)ase] enzyme. Many roles in cell growth and differentiation have been attributed to 1,25(OH)2D, including a central role in calcium homeostasis and skeletal metabolism. To investigate the in vivo functions of 1,25(OH)2D and the molecular basis of its actions, we developed a mouse model deficient in 1alpha(OH)ase by targeted ablation of the hormone-binding and heme-binding domains of the 1alpha(OH)ase gene. After weaning, mice developed hypocalcemia, secondary hyperparathyroidism, retarded growth, and the skeletal abnormalities characteristic of rickets. These abnormalities are similar to those described in humans with the genetic disorder vitamin D dependent rickets type I [VDDR-I; also known as pseudovitamin D-deficiency rickets (PDDR)]. Altered non-collagenous matrix protein expression and reduced numbers of osteoclasts were also observed in bone. Female mutant mice were infertile and exhibited uterine hypoplasia and absent corpora lutea. Furthermore, histologically enlarged lymph nodes in the vicinity of the thyroid gland and a reduction in CD4- and CD8-positive peripheral T lymphocytes were observed. Alopecia, reported in vitamin D receptor (VDR)-deficient mice and in humans with VDDR-II, was not seen. The findings establish a critical role for the 1alpha(OH)ase enzyme in mineral and skeletal homeostasis as well as in female reproduction and also point to an important role in regulating immune function.  相似文献   
43.
Purpose: Mobility Dogs® trains dogs to work with people with physical disabilities to increase independence, confidence, self-esteem and participation. Mobility Dogs® seeks to critically evaluate and improve its services as it grows. This study aimed to identify and implement a standardised outcome measure into practice at Mobility Dogs®. Method: Based on the Consolidated Framework for Implementation Research and guided by a steering group of key stakeholders, a three-phase approach was developed to identify and assess an outcome measure. The steering group highlighted the organisation’s specific needs, selected participation as the assessment domain and identified core utility requirements of the measure. A comprehensive review of evidence was undertaken to identify and rank potential measures according to the specified needs.

Results: Of the seven participation outcome measures that met inclusion criteria, the three highest ranked measures were critically evaluated by the steering group to determine suitability against the organisation’s needs. The Impact on Participation and Autonomy (IPA) was selected for implementation into practice at Mobility Dogs®. Conclusion: Use of the IPA is an important first step for Mobility Dogs® to test the benefits of trained service dogs. This process could be replicated by other service dog organisations to identify outcome measures to assess their own services.

  • Implications for Rehabilitation
  • Service dogs (such as Mobility Dogs® in New Zealand) assist people living with physical impairments by performing tasks, however there is limited evidence on outcomes.

  • The process for selecting an appropriate outcome measure for Mobility Dogs® involving partnership between Mobility Dogs® personnel and academics was an effective way to steer the project by determining important properties of the measure, before a search of the literature was undertaken.

  • While the IPA was selected as the most appropriate outcome measure for use at Mobility Dogs®, it was the process that is valuable to replicate if other organisations wish to select an outcome measure for use in their own practice.

  相似文献   
44.
Mudge S, Stott NS, Walt SE. Criterion validity of the StepWatch Activity Monitor as a measure of walking activity in patients after stroke.

Objectives

To test the validity of the StepWatch Activity Monitor (SAM) in subjects with stroke against 2 criterion standards, 3-dimensional gait analysis (3-DGA) and footswitches in a variety of indoor and outdoor walking conditions, including different speeds and different terrains, and to test the accuracy of the SAM when worn on the paretic limb.

Design

Criterion standard validation study.

Setting

Gait laboratory and outside course.

Participants

Twenty-five participants with physical disability after stroke.

Interventions

Not applicable.

Main Outcome Measures

The total step count measured simultaneously by SAM and either 3-DGA or footswitches for both paretic and nonparetic limbs.

Results

The total step count measured by the SAM and 3-DGA was highly correlated (nonparetic limb, r=.959; paretic limb, r=.896). The 95% limits of agreement (LOA) (derived from Bland-Altman analysis) between the SAM and 3-DGA were within ±10 steps for SAMs worn on either the nonparetic or paretic limb. The total step count measured simultaneously by the SAM and footswitches was also highly correlated for each limb (nonparetic, r=.999; paretic, r=.963). The 95% LOA between the SAM and footswitches were ±9 steps on the nonparetic limb but higher at ±57 steps on the paretic limb. Further analysis showed that the measurement differences occurred during the outdoor component of the combined walk. The 95% LOA between footswitches on both limbs were not more than ±9 steps for walking, suggesting that the error was accounted for by the SAM on the paretic limb, which both over- and underread the total step count in the outdoor walking conditions.

Conclusions

Criterion validity of the SAM to measure steps in both clinical and natural environments has been established when used on the nonparetic limb. However, more errors are apparent when the SAM is worn on the paretic limb while walking over a variety of outdoor terrains. Validation is recommended before use in patients with neurologic conditions affecting bilateral legs because there may be more error, particularly in outdoor activities.  相似文献   
45.
BACKGROUND: Hope as a universal human phenomenon has been studied from various perspectives often conceptualized as having a unified set of attributes. In this study however hope is viewed to be experienced by people in various patterns structured by different orientations and emphases depending upon their life circumstances. There is a paucity of studies in the literature examining patterns of hope experienced by people in chronic illness or in special life circumstances. OBJECTIVES: The aim of this study was to discover patterns of hope in hospitalized chronically ill patients and to identify the major threads that structure various patterns of hope experienced by them. DESIGN: Q-methodology, which is an approach designed to discover patterns in various subjective experiences, was used as the method for data collection and theory generation. Q-methodology involves five steps in its approach, the first two as the first phase and the last three as the second phase. The study was carried out at a general acute-care, tertiary hospital in a New England state in the US. The study obtained data from a convenient sample of 12 chronically ill patients and 16 oncology nurses for the first phase, and a different convenient sample of 20 chronically ill patients for the second phase. RESULTS AND CONCLUSIONS: Five patterns of subjective experiences of hope emerged as: (a) externalism orientation, (b) pragmatism orientation, (c) reality orientation, (d) future orientation, and (e) internalism orientation. This means that chronically ill patients experience hope in various ways by focusing on different dimensions of meaning, suggesting the conceptualization of hope as a unitary construct may not reflect people's experiences of hope accurately. The major implication of the study is to rethink ways to assess patients' hope in terms of pattern differences rather than in terms of quantity.  相似文献   
46.
Purpose: Non-ambulatory persons with cerebral palsy are prone to low bone mineral density. In ambulatory persons with cerebral palsy, bone mineral density deficits are expected to be small or absent, but a consensus conclusion is lacking. In this systematic review bone mineral density in ambulatory persons with cerebral palsy (Gross Motor Function Classification Scales I–III) was studied.

Materials and methods: Medline, Embase, and Web of Science were searched. According to international guidelines, low bone mineral density was defined as Z-score?≤??2.0. In addition, we focused on Z-score?≤??1.0 because this may indicate a tendency towards low bone mineral density.

Results: We included 16 studies, comprising 465 patients aged 1–65?years. Moderate and conflicting evidence for low bone mineral density (Z-score?≤??2.0) was found for several body parts (total proximal femur, total body, distal femur, lumbar spine) in children with Gross Motor Function Classification Scales II and III. We found no evidence for low bone mineral density in children with Gross Motor Function Classification Scale I or adults, although there was a tendency towards low bone mineral density (Z-score?≤??1.0) for several body parts.

Conclusions: Although more high-quality research is needed, results indicate that deficits in bone mineral density are not restricted to non-ambulatory people with cerebral palsy.

  • Implications for Rehabilitation
  • Although more high-quality research is needed, including adults and fracture risk assessment, the current study indicates that deficits in bone mineral density are not restricted to non-ambulatory people with CP.

  • Health care professionals should be aware that optimal nutrition, supplements on indication, and an active lifestyle, preferably with weight-bearing activities, are important in ambulatory people with CP, also from a bone quality point-of-view.

  • If indicated, medication and fall prevention training should be prescribed.

  相似文献   
47.
BACKGROUND/AIMS: To evaluate the outcome of patients who require continuous renal replacement therapy (CRRT) following cardiac surgery. METHODS: All patients who received CRRT after cardiac surgery over more than 4 years at the Surgical Intensive Care Unit of the Montreal Heart Institute were reviewed. Among 5,564 consecutive patients, 85 underwent CRRT postoperatively. RESULTS: The mean delay between surgery and CRRT initiation was 5 days, and the duration of CRRT was 9 days, without a difference between survivors and non-survivors. Delivered clearances with CRRT were estimated at 25-28 ml/min (approximately 40 liters/day), 29-32 ml/min (approximately 46 liters/day) and 17 ml/min (approximately 25 liters/day) for continuous veno-venous hemofiltration, continuous veno-venous hemodiafiltration and continuous veno-venous hemodialysis, respectively. In-hospital mortality was 43.5%. No difference in mortality was observed between patients with normal renal function at baseline and those with pre-operative renal dysfunction. Mortality was 33.3% after a coronary artery bypass graft (CABG), 57.1% after CABG and valve surgery, 60% after valve surgery, and 72.7% for redo-CABG or redo-valve surgery. 79% of survivors and 86% of non-survivors had received a cardiopulmonary bypass (p = NS). The Simplified Acute Physiology Score II upon intensive care unit (ICU) admission and the requirement of an intra-aortic balloon pump were higher in non-survivors (p < 0.05). The mean length of ICU and hospital stay was 27.4 and 34.2 days for survivors and 17.9 and 22.3 days for non-survivors, respectively (p < 0.05). CONCLUSIONS: Renal impairment is relatively common after cardiac surgery. The mortality of patients who required CRRT after cardiac surgery was 43.5% and was particularly influenced by the type of surgery.  相似文献   
48.
49.
The Hedgehog (Hh) pathway has been implicated in pancreatic cancer but its role remains controversial. To delineate the cell populations able to respond to Hh ligand stimulation, we expressed an oncogenic allele of Smoothened (SmoM2) to cell autonomously activate Hh signaling in the mouse pancreas. Surprisingly, we found that expression of SmoM2 in epithelial cells was not able to activate the pathway and had no impact on pancreatic development or neoplasia. In contrast, activation of Smo in the mesenchyme led to Hh pathway activation, indicating that only the tumor stroma is competent to transduce the Hh signal. Using a Ptc-LacZ reporter mouse, we show that Hh signaling is active in stromal cells surrounding Hh-expressing tumor epithelium in various mouse pancreatic cancer models. Activation of the Hh pathway in the tumor stroma of human pancreatic and metastatic cancer specimens was confirmed by quantitative RT-PCR of microdissected tissue samples. These data support a paracrine model of Hh-mediated tumorigenesis, in which tumor cells secrete Hh ligand to induce tumor-promoting Hh target genes in adjacent stroma.  相似文献   
50.
The testing of dried blood spots (DBSs) for human immunodeficiency type 1 (HIV-1) proviral DNA by PCR is a technology that has proven to be particularly valuable in diagnosing exposed infants. We implemented this technology for HIV-1 early infant diagnosis (EID) and HIV-1 RNA viral load determination in infants born of HIV-1-seropositive mothers from remote areas in Cameroon. The samples were collected between December 2007 and September 2010. Fourteen thousand seven hundred and sixty-three (14,763) DBS samples from infants born of HIV-positive mothers in 108 sites nationwide were tested for HIV. Of these, 1452 were positive on first PCR analyses (PCR1), giving an overall infection rate of 12.30%. We received only 475 DBS specimen for a second PCR testing (PCR2); out of these, 145 were positive. The median HIV-1 RNA viral load for 169 infant DBS samples tested was 6.85 log copies/ml, with values ranging from 3.37 to 8 log copies/ml. The determination of the viral load on the same DBS as that used for PCR1 allowed us to bypass the PCR2. The viral load values were high and tend to decrease with age but with a weak slope. The high values of viral load among these infants call for early and effective administration of antiretroviral therapy (ART). The findings from this study indicate that the use of DBS provides a powerful tool for perinatal screening programs, improvement on the testing algorithm, and follow-up during treatment, and thus should be scaled up to the entire nation.  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