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   1531篇
  免费   100篇
  国内免费   3篇
耳鼻咽喉   8篇
儿科学   27篇
妇产科学   7篇
基础医学   205篇
口腔科学   10篇
临床医学   209篇
内科学   363篇
皮肤病学   26篇
神经病学   210篇
特种医学   83篇
外科学   222篇
预防医学   89篇
眼科学   24篇
药学   79篇
肿瘤学   72篇
  2023年   23篇
  2022年   41篇
  2021年   97篇
  2020年   46篇
  2019年   84篇
  2018年   88篇
  2017年   68篇
  2016年   72篇
  2015年   87篇
  2014年   108篇
  2013年   123篇
  2012年   140篇
  2011年   125篇
  2010年   67篇
  2009年   57篇
  2008年   67篇
  2007年   60篇
  2006年   54篇
  2005年   37篇
  2004年   37篇
  2003年   27篇
  2002年   34篇
  2001年   5篇
  1999年   6篇
  1998年   2篇
  1997年   4篇
  1996年   4篇
  1995年   2篇
  1993年   5篇
  1992年   4篇
  1991年   2篇
  1990年   5篇
  1989年   3篇
  1988年   3篇
  1987年   2篇
  1986年   5篇
  1985年   3篇
  1984年   2篇
  1983年   4篇
  1981年   3篇
  1980年   3篇
  1979年   4篇
  1978年   3篇
  1977年   3篇
  1976年   1篇
  1975年   3篇
  1974年   2篇
  1973年   3篇
  1972年   2篇
  1970年   1篇
排序方式: 共有1634条查询结果,搜索用时 218 毫秒
51.
52.
BACKGROUND: It remains to be shown whether inflammatory bowel disease (IBD) is associated with an increased risk of primary intestinal lymphoproliferative disorders (PILD). We assessed this risk in the CESAME French nationwide prospective observational cohort. METHODS: In all, 680 gastroenterologists enrolled 19,486 patients with IBD (Crohn's disease in 60.3%) from May 2004 to June 2005. Follow-up ended on 31 December 2007. Available biopsy samples and surgical specimens from patients with PILD (n = 14) were centralized for review. The reference incidence of PILD in the general population was obtained from the C?te d'Or registry and was used as a comparator to assess the standardized incidence ratio (SIR). The influence of thiopurine exposure was explored in a nested case-control study. RESULTS: In the CESAME population the crude incidence of PILD was 0.12/1000 patient-years, with a corresponding SIR of 17.51 (95% confidence interval [CI], 6.43-38.11; P < 0.0001). The risk was highest in patients exposed to thiopurines (SIR 49.52, 95% CI 13.49-126.8; P < 0.0001), while it did not reach statistical significance in patients na?ve to thiopurines (SIR 4.83, 95% CI, 0.12-26.91; P = 0.37). The odds ratio associated with ongoing thiopurine exposure (vs. na?ve) was 2.97 (95% CI, 0.30-infinity; P = 0.38). All 14 cases of PILD were non-Hodgkin's B-cell LD, 78.6% occurred in males, 85.7% arose in IBD lesions, and 45.5% were Epstein-Barr virus-positive. Eleven cases occurred in patients with Crohn's disease. Mean (SD) age at PILD diagnosis was 55.1 (5.6) years and the median time since IBD onset was 8.0 years (interquartile range, 3.0-15.8). CONCLUSIONS: Patients with IBD have an increased risk of developing PILD. (Inflamm Bowel Dis 2012;).  相似文献   
53.
The practice of elective penicillin skin testing could be compromised by the fact that patients, their parents, or their physicians remain reluctant to reuse penicillin-class antibiotics (PCAs) despite a negative evaluation by an allergist. This study addresses reuse of PCAs in a pediatric population after negative penicillin skin testing and drug challenge and factors associated with its reluctance. All children evaluated for a history of penicillin allergy at the CHU Sainte-Justine Allergy Clinic between January 1998 and June 2000 with negative skin testing and drug challenge were included in the study. A telephone survey was conducted between May and October 2002 to assess the perception of the initial reaction by the parents, subsequent use of antibiotics, and antibiotic-related adverse reactions. Among the 200 children selected, parents of 170 (85%) children completed the survey. Since the allergist evaluation, 130 (76%) children had received antibiotics. PCA was used in 59 (45%) children. Parents of 24 (18%) children refused PCAs because they still feared an adverse reaction. They were more likely to have been very frightened by their child's allergic reaction than other parents whose children had used PCAs (p = 0.008). Although elective penicillin skin testing is useful and safe in the pediatric population, a significant proportion of parents still refuse PCAs even though they are needed. Identification of parents that were very frightened by their children's allergic reactions and additional reassurance could improve this situation.  相似文献   
54.

Background

Focal therapy (FT) for prostate cancer (PCa) seems to be part of a natural evolution in the quest to improve the management of early organ-confined disease.

Objective

To assess the morbidity of the initial experience of FT in a tertiary referral center for PCa management.

Design, setting, and participants

From 2009 to 2011, a total of 1213 patients with clinically localized PCa were treated at our institution. Of these patients, 547 were considered to have indolent disease according to the D’Amico criteria for low-risk disease plus unilateral disease with a maximum of three positive biopsies. A total of 106 patients underwent FT using high-intensity focused ultrasonography (HIFU), brachytherapy, cryotherapy, or vascular-targeted photodynamic therapy (VTP).

Outcome measurements and statistical analysis

Complications were prospectively recorded and graded according to the Clavien-Dindo scale. Data were prospectively collected and retrospectively analyzed.

Results and limitations

This study included 106 patients, median age 66.5 yr (interquartile range [IQR]): 61–73), who had a prostate hemiablation; 50 patients (47%) had cryotherapy, 23 patients (22%) had VTP, 21 patients (20%) received HIFU, and 12 patients (11%) had brachytherapy. The median prostate-specific antigen (PSA) level was 6.1 ng/ml (IQR: 5–8.1), all the patients had a biopsy Gleason score of 6, and the median prostate weight was 43 g (IQR: 33–55). The median International Prostate Symptom Score was 6 (IQR: 3–10), and the median International Index of Erectile Function score was 20 (IQR: 15–23). After treatment, the median PSA at 3, 6, and 12 mo was 3.1 2.9, and 2.7 ng/ml (IQR: 2–5.1, 1.1–4.7, and 1–4.4), respectively. Thirteen percent of the patients experienced treatment-related complications. There were 11 minor medical complications (10 grade 1 complications and 1 grade 2 complication), 2 grade 3 complications, and no grade 4 or higher complications.

Conclusions

FT for a highly selected population with PCa is feasible and had an acceptable morbidity with <2% major complications.  相似文献   
55.
56.
57.
Dual-task designs have been used widely to study the degree of automatic and controlled processing involved in postural stability of young and older adults. However, several unexplained discrepancies in the results weaken this literature. To resolve this problem, a careful selection of dual-task studies that met certain methodological criteria are considered with respect to reported interactions of age (young vs. older adults) × task (single vs. dual task) in stable and unstable postural conditions. Our review shows that older adults are able to perform a postural dual task as well as younger adults in stable conditions. However, when the complexity of the postural task is increased by dynamic conditions (surface and surround), performance in postural, concurrent, or both tasks is more affected in older relative to young adults. In light of neuroimaging studies and new conceptual frameworks, these results demonstrate an age-related increase of controlled processing of standing associated with greater intermittent adjustments.  相似文献   
58.
This study investigated weight status related differences in executive functions and movement execution to determine whether or not childhood obesity is associated with impaired perceptual-motor function. Nineteen obese (OB) children (10 ♂ and 9 ♀, aged 6–12 years) and nineteen gender and age matched healthy-weight (HW) peers performed two computer-based reaction time tasks. For both the simple and four choice reaction time (SRT/CRT) task condition, absolute mean reaction time (RT) and movement time (MT) were determined and expressed as a percentage of total response time (RsT). During the SRT task, OB children were intrinsically slower than their HW peers as reflected by a significantly higher absolute RT, MT and RsT. In the CRT task, however, between-group differences were only present for RT and RsT, whereas absolute MT was comparable among OB and HW participants. As a result, the relative temporal structure of RsT significantly differed between BMI groups, with a greater RT percentage among the OB children. During the CRT condition, OB children probably await final decision-making with regard to the execution of their response movement, which then no longer needs to be adjusted. Our results therefore indicate the use of a more conservative strategy within the OB group, suggesting that childhood obesity is associated with impaired perceptual-motor function. Besides the widely accepted mechanical explanation, a better understanding of the mechanisms underlying OB children's motor incompetence is needed to set up appropriate interventions to tackle this deficit and indirectly address associated health-related problems.  相似文献   
59.
The purpose of the present experiment was to investigate whether the sensory weighting of a plantar pressure-based, tongue-placed tactile biofeedback for controlling posture could be subject to inter-individual variability. To achieve this goal, 60 young healthy adults were asked to stand as immobile as possible with their eyes closed in two conditions of No-biofeedback and Biofeedback. Centre of foot pressure (CoP) displacements were recorded using a force platform. Overall, results showed reduced CoP displacements in the Biofeedback relative to the No-biofeedback condition, evidencing the ability of the central nervous system to efficiently integrate an artificial plantar-based, tongue-placed tactile biofeedback for controlling posture during quiet standing. Results further showed a significant positive correlation between the CoP displacements measured in the No-biofeedback condition and the decrease in the CoP displacements induced by the use of the biofeedback. In other words, the degree of postural stabilization appeared to depend on each subject's balance control capabilities, the biofeedback yielding a greater stabilizing effect in subjects exhibiting the largest CoP displacements when standing in the No-biofeedback condition. On the whole, by evidencing a significant inter-individual variability in sensory weighting of an additional tactile information related to foot sole pressure distribution for controlling posture, the present findings underscore the need and the necessity to address the issue of inter-individual variability in the field of neuroscience.  相似文献   
60.
We investigated the visual word recognition ability of M.T., a young boy with surface dyslexia, by means of a paradigm that measures performance as a function of the eye fixation position within the word, known as the "viewing-position effect" paradigm. In well-achieving readers, the viewing-position effect is mainly determined by factors affecting letter visibility and by lexical constraints on word recognition. We further quantified M.T.'s sensory limitations on letter visibility by computing visual-span profiles - that is, the number of letters recognizable at a glance. Finally, in an ideal-observer's perspective, M.T.'s performance was compared with a parameter-free model combining M.T.'s letter visibility data with a simple lexical matching rule. The results showed that M.T. did not use the whole visual information available on letter identities to recognize words and that preorthographical factors constrained his word recognition performance. The results can be best accounted for by a reduction of the number of letters processed in parallel.  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