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   1324篇
  免费   95篇
  国内免费   2篇
耳鼻咽喉   8篇
儿科学   22篇
妇产科学   23篇
基础医学   273篇
口腔科学   21篇
临床医学   173篇
内科学   237篇
皮肤病学   8篇
神经病学   107篇
特种医学   31篇
外科学   153篇
综合类   4篇
预防医学   106篇
眼科学   14篇
药学   104篇
肿瘤学   137篇
  2024年   2篇
  2023年   15篇
  2022年   20篇
  2021年   48篇
  2020年   31篇
  2019年   40篇
  2018年   56篇
  2017年   29篇
  2016年   38篇
  2015年   42篇
  2014年   57篇
  2013年   51篇
  2012年   133篇
  2011年   111篇
  2010年   79篇
  2009年   45篇
  2008年   98篇
  2007年   99篇
  2006年   85篇
  2005年   85篇
  2004年   71篇
  2003年   75篇
  2002年   63篇
  2001年   5篇
  2000年   2篇
  1999年   5篇
  1998年   4篇
  1997年   3篇
  1996年   3篇
  1995年   3篇
  1994年   5篇
  1993年   3篇
  1992年   1篇
  1990年   1篇
  1989年   1篇
  1987年   3篇
  1984年   2篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
  1980年   2篇
  1979年   1篇
排序方式: 共有1421条查询结果,搜索用时 15 毫秒
991.
This study mapped the movements of Permanent Health Education in the region of Araraquara, S?o Paulo, Brazil, begun by the Permanent Health Education Facilitators program, promoted by the Ministry of Health and the National School of Public Health. This qualitative study was grounded on the theoretical framework of institutional and schizoanalysis. Data were collected from operative groups of individuals who finished the program. The results were grouped into two plans: micropolitics and organization. Micropolitics indicates the production of different concepts concerning permanent education and different ways to establish it. Autonomy and control and also a tenuous relationship between tutorship and autonomy were highlighted, in the plan of organization. In conclusion, the program was an important device that suffered captures/overcoding but also produced changes in practice.  相似文献   
992.

Purpose

To compare magnetic resonance imaging (MRI) brain feature in cryptogenic stroke patients with patent foramen ovale (PFO), cryptogenic stroke patients without PFO and patients with cardioembolic stroke.

Materials and methods

The ethics committee required neither institutional review board approval nor informed patient consent for retrospective analyses of the patients’ medical records and imaging data. The patients’ medical files were retrospectively reviewed in accordance with human subject research protocols. Ninety-two patients under 60 years of age were included: 15 with cardioembolic stroke, 32 with cryptogenic stroke with PFO and 45 with cryptogenic stroke without PFO. Diffusion-weighted imaging of brain MRI was performed by a radiologist blinded to clinical data. Univariate, Fischer's exact test for qualitative data and non-parametric Wilcoxon test for quantitative data were used.

Results

There was no statistically significant difference found between MRI features of patients with PFO and those with cardioembolic stroke (p < .05). Patients without PFO present more corticosubcortical single lesions (p < .05) than patients with PFO. Patients with PFO have more often subcortical single lesions larger than 15 mm, involvement of posterior cerebral arterial territory and intracranial occlusion (p < .05) than patients with cryptogenic stroke without PFO.

Conclusion

Our study suggests a cardioembolic mechanism in ischemic stroke with PFO.  相似文献   
993.

Purpose

To evaluate whether medial open wedge high tibial osteotomy (HTO) results in structural changes in the articular cartilage in the lateral tibiofemoral compartment of adult sheep.

Methods

Three experimental groups received biplanar osteotomies of the right proximal tibiae: (a) closing wedge HTO (4.5° of tibial varus), (b) opening wedge HTO (4.5° tibial valgus; standard correction), and (c) opening wedge HTO (9.5° of valgus; overcorrection), each of which was compared to the contralateral knees that only received an arthrotomy. After 6 months, the macroscopic and microscopic characteristics of the articular cartilage of the lateral tibiofemoral compartment were assessed.

Results

The articular cartilage in the central region of the lateral tibial plateau in sheep had a higher safranin O staining intensity and was 4.6-fold thicker than in the periphery (covered by the lateral meniscus). No topographical variation in the type-II collagen immunoreactivity was seen. All lateral tibial plateaus showed osteoarthritic changes in regions not covered by the lateral meniscus. No osteoarthritis was seen in the peripheral submeniscal regions of the lateral tibial plateau and the lateral femoral condyle. Opening wedge HTO resulting in both standard and overcorrection was not associated with significant macroscopic and microscopic structural changes between groups in the articular cartilage of the lateral tibial plateau and femoral condyle after 6 months in vivo.

Conclusion

Opening wedge HTO resulting in both standard and overcorrection is a safe procedure for the articular cartilage in an intact lateral tibiofemoral compartment of adult sheep at 6 months postoperatively.  相似文献   
994.
Some patients happen to have a colorectal cancer with microsatellite instability (MSI), but without any alteration in Mismatch Repair (MMR) system (germline mutation/promoter methylation). We aimed to identify the mechanism of inactivation of MMR genes in those cases. We studied 18 patients with MSI CCR and loss of expression of a MMR protein. DNA was extracted from tumoral and normal colonic material. We studied the 3 main MMR genes in tumors, by sequencing and large rearrangement analysis, and looked for mosaicism. Seven patients lost expression of MLH1, we found 1 mutation in the tumor for 3 patients and 2 mutations in one. Eight patients lost expression of MSH2: we found 1 mutation in 2 patients and 2 mutations in four. In the 5 cases with 2 hits, MSI was due to double somatic hits (n = 3), mosaicism (n = 1) and missed germline mutation (n = 1). Mosaicism was confirmed by HRM analysis, and by finding a germline mutation in one patient’s son. We could explain MSI in the tumors of 5 patients (27.8 %). Their follow up and family’s surveillance could be adjusted, as the sporadic cases don’t require intensive surveillance. We describe the first case of somatic mosaicism after de novo mutation in MSH2.  相似文献   
995.

Purpose

The present study examined the predictive value of emotional competence and the five-factor model of personality on the quality of life of children with asthma.

Methods

Participants were 90 children (M age = 11.73, SD = 2.60) having controlled and partly controlled asthma, undergoing everyday treatment. Children filled in questionnaires assessing emotional competence and quality of life. Parents completed questionnaires assessing the personality of their child.

Results

Results showed that two emotional competences, bodily awareness and verbal sharing of emotions, were related to the quality of life of children with asthma. Moreover, one personality trait, benevolence, was associated with children’s quality of life. Regression analyses showed that the predictive value of these three dimensions remained significant over and above asthma control and socio-demographic variables frequently associated with the quality of life of children with asthma (age, gender, and educational level of parents).

Conclusions

These findings emphasize the importance of alerting the clinician who works with children with asthma to observe and assess the child’s expression of emotions, attention to bodily sensations, and benevolence.  相似文献   
996.

Objectives

To describe the clinical features, radiological findings, treatment and outcomes of three cases of endolymphatic sac tumors (ELST).

Methods

Retrospective analysis of three cases of ELST.

Results

The first patient had a large ELST invading the labyrinth after a long history of vertigo. He was recurrence-free 1 year after retrolabyrinthine surgical removal. In the second case, an acute peripheral facial nerve paralysis associated with ipsilateral sensorineural hearing loss led to the diagnosis. A translabyrinthine approach was used to remove the tumor, which recurred three times over 10 years. The third patient was a young woman suffering from von Hippel–Lindau (VHL) disease and referred for a sudden sensorineural hearing loss due to an intralabyrinthine hemorrhage secondary to a 2 mm-large endolymphatic sac-confined ELST. Her hearing was totally lost after the deafness recurred 1 month after this first episode. MRI demonstrated a small bilateral ELST. The patient refused surgery on the deaf side.

Conclusion

ELST are difficult to diagnose due to the wide variety of their presentations. Patients with ELST should be screened for VHL disease. Dural invasion and tumor hypervascularization increase the risk of local recurrences after surgery. Early surgical resection may lead to complete tumor removal and inner ear preservation.  相似文献   
997.

Background

As soon as Diagnosis related Groups (DRG) were introduced in many hospital financing systems, most nursing research revealed that DRG were not very homogeneous with regard to nursing care. However, few studies are based on All Patient refined Diagnosis related Groups (APR-DRGs) and few of them use recent data. Objectives of this study are: (1) to evaluate if nursing activity is homogeneous by APR-DRG and by severity of illness (SOI) (2) to evaluate the outlier’s rate associated with the nursing activity and (3) to compare nursing cost homogeneity per DRG and SOI.

Methods

Study done in 9 Belgian hospitals on a selection of APR-DRG with more than 30 patients (7 638 inpatient stays). The evaluation of the homogeneity is based on coefficients of variation (CV). The 75th percentile?+?1.5?×?inter-quartile range was used to select high outliers. 25th percentile ?1.5?×?inter-quartile range was used to select low outliers. Nursing costs per ward were distributed on inpatient stays of each ward following two techniques (the LOS vs. the number of nursing care minutes per stay).

Results

The homogeneity of LOS by DRG and by SOI is relatively good (CV: 0.56). The homogeneity of the nursing activity by DRG is less good (CVs between 0.36 and 1.54) and is influenced by nursing activity outliers (high outliers’ rate: 5.19%, low outliers’ rate: 0.14%). The outlier’s rate varies according to the studied variable. The high outliers’ rate is higher for nursing activity than for LOS. The homogeneity of nursing costs is higher when costs are based on the LOS of patients than when based on minutes of nursing care (CVs between 0.26 and 1.46 for nursing costs based on LOS and between 0.49 and 2.04 for nursing costs based on minutes of nursing care).

Conclusions

It is essential that the calculation of nursing cost by stay and by DRG for hospital financing purposes was based on nursing activity data, that more reflect resources used in wards, and not on LOS data. The only way to obtain this information is the generalization of computerized nursing files.
  相似文献   
998.
Large dsDNA viruses are involved in the population control of many globally distributed species of eukaryotic phytoplankton and have a prominent role in bloom termination. The genus Phaeocystis (Haptophyta, Prymnesiophyceae) includes several high-biomass-forming phytoplankton species, such as Phaeocystis globosa, the blooms of which occur mostly in the coastal zone of the North Atlantic and the North Sea. Here, we report the 459,984-bp-long genome sequence of P. globosa virus strain PgV-16T, encoding 434 proteins and eight tRNAs and, thus, the largest fully sequenced genome to date among viruses infecting algae. Surprisingly, PgV-16T exhibits no phylogenetic affinity with other viruses infecting microalgae (e.g., phycodnaviruses), including those infecting Emiliania huxleyi, another ubiquitous bloom-forming haptophyte. Rather, PgV-16T belongs to an emerging clade (the Megaviridae) clustering the viruses endowed with the largest known genomes, including Megavirus, Mimivirus (both infecting acanthamoeba), and a virus infecting the marine microflagellate grazer Cafeteria roenbergensis. Seventy-five percent of the best matches of PgV-16T–predicted proteins correspond to two viruses [Organic Lake phycodnavirus (OLPV)1 and OLPV2] from a hypersaline lake in Antarctica (Organic Lake), the hosts of which are unknown. As for OLPVs and other Megaviridae, the PgV-16T sequence data revealed the presence of a virophage-like genome. However, no virophage particle was detected in infected P. globosa cultures. The presence of many genes found only in Megaviridae in its genome and the presence of an associated virophage strongly suggest that PgV-16T shares a common ancestry with the largest known dsDNA viruses, the host range of which already encompasses the earliest diverging branches of domain Eukarya.  相似文献   
999.
Sexual dimorphism has already been described in temporal lobe epilepsy with mesial temporal sclerosis (TLE-MTS). This study evaluated the effect of gender on amygdala volume in patients with TLE-MTS. One hundred twenty-four patients with refractory unilateral or bilateral TLE-MTS who were being considered for epilepsy surgery underwent a comprehensive presurgical evaluation and MRI. Amygdalas of 67 women (27 with right; 32 with left, and 8 with bilateral TLE) and 57 men (22 with right, 30 with left, and 5 with bilateral TLE) were manually segmented. Significant ipsilateral amygdala volume reduction was observed for patients with right and left TLE. No gender effect on amygdala volume was observed. Contralateral amygdalar asymmetry was observed for patients with right and left TLE. Although no gender effect was observed on amygdala volume, ipsilateral amygdala volume reductions in patients with TLE might be related to differential rates of cerebral maturation between hemispheres.  相似文献   
1000.
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