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   3232篇
  免费   229篇
  国内免费   18篇
耳鼻咽喉   10篇
儿科学   84篇
妇产科学   56篇
基础医学   379篇
口腔科学   175篇
临床医学   264篇
内科学   619篇
皮肤病学   124篇
神经病学   250篇
特种医学   86篇
外科学   446篇
综合类   61篇
预防医学   252篇
眼科学   201篇
药学   302篇
中国医学   30篇
肿瘤学   140篇
  2024年   1篇
  2023年   48篇
  2022年   57篇
  2021年   183篇
  2020年   130篇
  2019年   190篇
  2018年   200篇
  2017年   145篇
  2016年   161篇
  2015年   140篇
  2014年   189篇
  2013年   227篇
  2012年   350篇
  2011年   330篇
  2010年   176篇
  2009年   141篇
  2008年   175篇
  2007年   191篇
  2006年   134篇
  2005年   117篇
  2004年   71篇
  2003年   52篇
  2002年   41篇
  2001年   4篇
  2000年   5篇
  1999年   4篇
  1998年   4篇
  1997年   2篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1990年   1篇
  1989年   2篇
  1988年   2篇
  1987年   2篇
排序方式: 共有3479条查询结果,搜索用时 31 毫秒
1.
2.
Background:Nursing work environment consists of a number of work-related psychosocial risk factors such as excessive workloads, lack of social support, emotional demands, job insecurity and confronting with challenging situations all of which may induce burnout. The aim of the current study was to investigate the relationship between work-related psychosocial factors and burnout among Iranian nurses.Methods:A cross-sectional study was carried out among 522 nurses. The data related to work-related psychosocial factors and burnout was gathered using Job Content Questionnaire (JCQ) and Maslach Burnout Inventory (MBI), respectively. Pearson’s correlation coefficients were used to examine the relationship between work-related psychosocial factors and burnout.Results:Mean scores of the dimensions of burnout for emotional exhaustion, depersonalization, and reduced personal accomplishment were 13.6 (SD=8.6), 18.42 (SD=7.1), and 28.45 (SD= 9.15), respectively. Psychological and physical job demands were positively correlated with different dimensions of burnout while social support and job control showed negative correlation with them.Conclusion:Appropriate interventions on reducing job demands both psychologically and physically and increasing social support and job control are suggested in prevention of burnout among the studied nurses.Key words: Burnout, psychosocial factors, nurses, job demands, job control, social support  相似文献   
3.
Background:Modern technology has reduced physical workload and imposed high mental workload on the control room operators in industrial settings. The present study was conducted among control room operators to assess their mental workload, investigate their workability, examine the relationship between mental workload and workability, and determine the factors associated with workability.Methods:This cross-sectional study was carried out among 213 control room operators in six Iranian process industries. Task Load Index (NASA-TLX) was used to assess the mental workload, and Work Ability Index (WAI) was used to determine workability. The relationships between demographic characteristics and dimensions of mental workload and workability were examined by univariate tests. Logistic regression analysis was also used to determine the factors associated with the operators’ workability.Results:The results showed a high mental workload in the study population (82.38±8.8). Yet, the operators showed a good and excellent level of workability (56.4%). Pearson’s correlation coefficient revealed a significant inverse linear relationship between the mean score of mental workload and workability (r=-0.581). Besides, regression modeling demonstrated that mental demand (OR=0.90), temporal demand (OR=0.90), effort (OR=0.91), frustration (OR=0.92), from NASA-TLX subscales were significantly associated with workability. Moreover, mental and temporal demands were important factors associated with reduced workability.Conclusion:Monitoring tasks imposes high mental workload on the control room operators, which may result in adverse effects on their workability as well as on the safety of the system.Key words: Mental workload, NASA-TLX, work ability, control room  相似文献   
4.
Aim: To examine the efficacy of cognitive rehabilitation treatment (CRT) for people with opioid use disorder who were recruited into a methadone maintenance treatment (MMT) programme.

Method: 120 male subjects were randomly assigned to (1) MMT plus CRT in two months or (2) MMT plus a control intervention. Subjects were assessed at the beginning, mid-point and post-intervention as well as at 1-, 3- and 6-month follow-up time points.

Results: Analysis with repeated measure ANOVA showed that the CRT group performed significantly better in tests of learning, switching, processing speed, working memory and memory span. Moreover, the CRT group had significantly lower opiate use over the control group during 3-months follow-up. Analysis including only those with a history of methamphetamine use showed that the CRT group had significantly lower amphetamine use. No group differences were observed for treatment retention.

Conclusions: Our findings provide evidence that adding CRT as an adjunct intervention to MMT can improve cognitive performance as well as abstinence from both opiates and stimulants.  相似文献   

5.
Purpose: Traffic accidents are one of the major health problems in the world, being the first cause of burden of illness and the second leading cause of death in Iran. The Sistan-Baluchestan province is one of the most accidental provinces of Iran with the highest rate of accidents-caused deaths. This study was conducted to determine the risk factors associated with traffic accidents in Zahedan through 2013 to 2016. Methods: This analytical cross-sectional study was carried out on 223 drivers from Zahedan who were traumatized by traffic accident and sent to Zahedan hospitals. The data were obtained through interviews taken by the trained interviewers via refereeing to the medical records and collected in the researcher-made checklist. Census was obtained from the study subjects. For data analysis, independent t-test, one-way ANOVA, Chi-square and logistic regression were used with the Stata software version 11.0. Results: In this study, 223 male subjects with the mean age of (32.54 ± 12.95) years, 39.8% single and 60.2% married, entered for investigation. Most accidents (38.8%) occurred between 12:00 to 17:59. While driving, 47.1% of the study subjects were using cell phones, 89.1% had manual use of mobile phones, 21.9% had a habit of sending short message service (SMS) and 23.4% had sent SMS within 10 min before the accident. The one way analysis of variance showed that the mean age of individuals with marital status, driving experience, education and accident with motorcycle were significantly different (p < 0.05). Also, the multivariate logistic regression test indicated a significant relationship of smoking, ethnicity, insurance and SMS typing while driving with motorcycle accident (p < 0.05). Conclusion: In this study, SMS and smoking while driving had the highest risk among the variables studied in the motorcycle accidents. Therefore, effective education attempting to enhance people''s awareness about the consequences of using cell phone and smoking during driving to reduce traffic accidents seems necessary.  相似文献   
6.
BackgroundAcetylcholine deficiencies in hippocampus and cortex, aggregation of β-amyloid, and β-secretase over activity have been introduced as main reasons in pathogenesis of Alzheimer’s disease.MethodsColorimetric Ellman’s method was used for determination of IC50 value in AChE and BChE inhibitory activity. The kinetic studies, neuroprotective and β-secretase inhibitory activities, evaluation of inhibitory potency on β-amyloid (Aβ) aggregations induced by AChE, and docking study were performed for prediction of the mechanism of action.Result and discussionA new series of cinnamic acids-tryptamine hybrid was designed, synthesized, and evaluated as dual cholinesterase inhibitors. These compounds demonstrated in-vitro inhibitory activities against acetyl cholinesterase (AChE) and butyryl cholinesterase (BChE). Among of these synthesized compounds, (E)-N-(2-(1H-indol-3-yl)ethyl)-3-(3,4-dimethoxyphenyl)acrylamide (5q) demonstrated the most potent AChE inhibitory activity (IC50 = 11.51 μM) and (E)-N-(2-(1H-indol-3-yl)ethyl)-3-(2-chlorophenyl)acrylamide (5b) were the best anti-BChE (IC50 = 1.95 μM) compounds. In addition, the molecular modeling and kinetic studies depicted 5q and 5b were mixed type inhibitor and bound with both the peripheral anionic site (PAS) and catalytic sites (CAS) of AChE and BChE. Moreover, compound 5q showed mild neuroprotective in PC12 cell line and weak β-secretase inhibitory activities. This compound also inhibited aggregation of β-amyloid (Aβ) in self-induced peptide aggregation test at concentration of 10 μM.ConclusionIt is worth noting that both the kinetic study and the molecular modeling of 5q and 5b depicted that these compounds simultaneously interacted with both the catalytic active site and the peripheral anionic site of AChE and BChE. These findings match with those resulted data from the enzyme inhibition assay. Graphical abstractOpen in a separate windowA new series of cinnamic-derived acids-tryptamine hybrid derivatives were designed, synthesized and evaluated as butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) inhibitors and neuroprotective agents. Compound 5b and 5q, as the more potent compounds, interacted with both the peripheral site and the choline binding site having mixed type inhibition. Results suggested that derivatives have a therapeutic potential for the treatment of AD.Electronic supplementary materialThe online version of this article (10.1007/s40199-020-00346-9) contains supplementary material, which is available to authorized users.  相似文献   
7.
8.
9.

Purpose

To investigate the preoperative use of combination metformin and statin versus monotherapy on biochemical recurrence (BCR) after radical prostatectomy (RP) in diabetic men.

Patients and Methods

Data of 843 diabetic men who underwent RP were stratified on the basis of preoperative use of no drug or of metformin, statin, or both. Multivariable Cox models were used to test the association between treatment and BCR. In a secondary analysis, models were stratified by race and body mass index (BMI) and further adjusted for glycated hemoglobin (HbA1c).

Results

A total of 259 men (31%) received statin therapy, 94 (11%) metformin, 307 (36%) metformin + statin, and 183 (22%) neither. Five-year BCR-free survival rates were 75% in metformin only versus 75% in metformin + statin versus 60% in statin versus 68% in no drug groups (log-rank, P = .003). On multivariable analysis, preoperative statin use was associated with increased BCR risk versus men receiving neither drug (hazard ratio [HR] = 1.84; 95% confidence interval [CI], 1.28-2.64). Metformin alone (HR 0.88; 95% CI, 0.53-1.47) and metformin + statin (HR 0.88; 95% CI, 0.58-1.33) were unrelated to BCR risks. In secondary analysis, the association between statin use and higher BCR risk was similar regardless of race, but was stronger among men with BMI ≥ 30 kg/m2 (HR 3.12; 95% CI, 1.70-5.72). These results were largely unchanged after adjusting for HbA1c.

Conclusion

Among diabetic men undergoing RP, preoperative statin use was associated with worse BCR risk, especially among men with a high BMI, but these associations may be mitigated by concomitant use of metformin. If validated in future findings, research is needed to understand the basis for these associations.  相似文献   
10.
Purpose: To compare the subclinical inflammatory response (as measured by anterior chamber flare) induced after standard (3 mW/cm2, 30 min) and accelerated (18 mW/cm2, 5 min) corneal cross-linking (CXL).

Methods: In this comparative, non-randomized study, patients with progressive keratoconus who underwent standard or accelerated CXL were studied. Laser flare photometery (FM-600; Kowa, Tokyo, Japan) was used to measure anterior chamber flare preoperatively and at 1 week, 1 month, 3 months, and 6 months after the procedure.

Results: Sixty eyes of 60 patients were studied; 30 eyes in each group. Mean baseline flare values were 4.15 ± 1.19 and 4.57 ± 2.17 ph/ms in standard and accelerated groups, respectively (p = 0.228).and after surgery increased in all follow-up measurements in the both groups similarly (P > 0.05).

Conclusion: Both standard and accelerated CXL results in induction of a subclinical inflammatory response that persists up to 6 month. The response was similar between the two groups.  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