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   8707篇
  免费   476篇
  国内免费   16篇
耳鼻咽喉   44篇
儿科学   288篇
妇产科学   224篇
基础医学   1056篇
口腔科学   57篇
临床医学   1586篇
内科学   1372篇
皮肤病学   97篇
神经病学   914篇
特种医学   132篇
外科学   714篇
综合类   80篇
一般理论   9篇
预防医学   1286篇
眼科学   103篇
药学   651篇
中国医学   7篇
肿瘤学   579篇
  2024年   7篇
  2023年   31篇
  2022年   81篇
  2021年   167篇
  2020年   90篇
  2019年   178篇
  2018年   176篇
  2017年   148篇
  2016年   169篇
  2015年   203篇
  2014年   307篇
  2013年   472篇
  2012年   671篇
  2011年   671篇
  2010年   365篇
  2009年   342篇
  2008年   612篇
  2007年   607篇
  2006年   619篇
  2005年   617篇
  2004年   601篇
  2003年   593篇
  2002年   501篇
  2001年   64篇
  2000年   42篇
  1999年   75篇
  1998年   99篇
  1997年   69篇
  1996年   75篇
  1995年   73篇
  1994年   46篇
  1993年   48篇
  1992年   26篇
  1991年   33篇
  1990年   21篇
  1989年   25篇
  1988年   33篇
  1987年   17篇
  1986年   11篇
  1985年   27篇
  1984年   26篇
  1983年   20篇
  1982年   27篇
  1981年   23篇
  1980年   22篇
  1979年   12篇
  1978年   18篇
  1977年   10篇
  1975年   6篇
  1974年   11篇
排序方式: 共有9199条查询结果,搜索用时 15 毫秒
991.
Cheryl Emich 《Nursing forum》2018,53(4):567-573
Nurses practicing at every level need a clear definition of collaboration before applying the concept in daily practice. Additionally, a conceptual definition of collaboration in nursing assists nurse researchers in finding or developing instruments for measuring collaboration and attributes of collaboration, which will enhance research findings. Collaboration extends beyond communication and includes sharing, teamwork, and respect. Multiple databases including CINAHL, PubMed, and ERIC were searched using the keywords collaboration, nursing, concept analysis, sharing, respect, and teamwork. For this analysis, using Walker and Avant’s method, the conceptual definition of collaboration in nursing is an intraprofessional or interprofessional process by which nurses come together and form a team to solve a patient care or healthcare system problem with members of the team respectfully sharing knowledge and resources. Two instruments consistent with the conceptual definition of collaboration are The Mayo High Performance Teamwork Scale (MHPTS) and Team Strategies and Tools to Enhance Performance and Patient Safety (Team STEPPS) and these instruments are summarized in this study. Finally, case scenarios are given to illustrate exemplars of collaboration in clinical practice.  相似文献   
992.
993.

Objectives

To investigate the relation between consciousness and nociceptive responsiveness (ie, Nociception Coma Scale–Revised [NCS-R]), to examine the suitability of the NCS-R for assessing nociception in participants with disorders of consciousness (DOC), and to replicate previous findings on psychometric properties of the scale.

Design

Specialized DOC program.

Setting

Specialized DOC program and university hospitals.

Participants

Participants (N=85) diagnosed with DOC.

Interventions

Not applicable.

Main Outcome Measures

We prospectively assessed consciousness with the Coma Recovery Scale–Revised (CRS-R). Responses during baseline, non-noxious, and noxious stimulations were scored with the NCS-R and CRS-R oromotor and motor subscales.

Results

CRS-R total scores correlated with NCS-R total scores and subscores. CRS-R motor subscores correlated with NCS-R total scores and motor subscores, and CRS-R oromotor subscores correlated with NCS-R total scores as well as verbal and facial expression subscores. There was a difference between unresponsive wakefulness syndrome and minimally conscious state in the proportion of grimacing and/or crying participants during noxious conditions. We replicated previous findings on psychometric properties of the scale but found a different score as the best threshold for nociception.

Conclusions

We report a strong relation between the responsiveness to nociception and the level of consciousness. The NCS-R seems to be a valuable tool for assessing nociception in an efficient manner, but additional studies are needed to allow recommendations for clinical assessment of subjective pain experience.  相似文献   
994.

Objective

To compare temporal activation patterns from 24 abdominal and lumbar muscles between healthy subjects and those who reported recovery from recent low back injury (LBI).

Design

Cross-sectional comparative study.

Setting

University neuromuscular function laboratory.

Participants

Healthy adult volunteers (N=81; 30 LBI, 51 asymptomatic subjects).

Interventions

Trunk muscle electromyographic activity was collected during 2 difficulty levels of a supine trunk stability test aimed at challenging lumbopelvic control.

Main Outcome Measures

Principal component (PC) analysis was applied to determine differences in temporal and/or amplitude electromyographic patterns between groups. Mixed-model analyses of variance were performed on PC scores that explained more than 89% of the variance (α=.05).

Results

Four PCs explained 89% and 96% of the variance for the abdominal and back muscles, respectively, with both muscle groups having similar shapes in the first 3 PCs. Significant interactions or group main effects were found for all PC scores except PC4 for the back extensors. Overall activation amplitudes for both the abdominal and back muscles (PC1 scores) were significantly (P<.05) higher for the LBI group, with both abdominal and back muscles of the LBI group demonstrating an increased response to the leg-loading phase (PC2 scores) compared with the asymptomatic group. Differences were also found between groups in their preparatory activity (PC3 scores), with the LBI group having a higher early relative amplitude of abdominal and back extensor activity.

Conclusions

Despite perceived readiness to return to work and low pain scores, muscle activation patterns remained altered in this LBI group, including reduced synergistic coactivation and increased overall amplitudes as well as greater relative amplitude differences during specific phases of the movement. Electromyographic measures provide objective information to help guide therapy and may assist with determining the level of healing and return-to-work readiness after an LBI.  相似文献   
995.
BACKGROUND: Over the last 15 years large changes in both alcohol consumption and the health care system have occurred in Poland. Substantial fluctuations in alcohol-related mortality followed and burden on health services increased, but data on risk of injury from alcohol consumption are relatively scarce METHODS: Estimates for risk of injury from drinking within six hours prior to the event are reported in samples of emergency services patients from Warsaw (n=508) and Sosnowiec (n=432), using case-crossover analysis based on usual frequency of drinking RESULTS: A four-fold risk of injury was found for those reporting drinking prior to injury compared to those not drinking, and this was significantly greater for those positive for alcohol use disorders compared to those negative. Relative risk of injury was marginally greater in Sosnowiec (5.2) compared to Warsaw (3.4) (p=0.06), and was significantly greater for those under 30. A 17-fold increase in risk for violence-related injury was found, and was significantly greater for females than males. Risk was substantially greater in Sosnowiec compared to Warsaw across all subgroups, but differences were not significant, possibly due to the small numbers of those sustaining injuries from violence in Warsaw. DISCUSSION: Injury risk related to drinking was expected to be significantly greater in Sosnowiec, due to more traditional drinking styles of infrequent intake of large quantities of spirits, than in Warsaw, but this was only partially borne out by these data. Risk estimates for all injuries were similar to those found in other case-crossover studies in emergency departments. Given the high relative risk estimates for injury related to drinking prior to the event, among both problem and non-problem drinkers, hospital-based emergency services in Poland may be an important site for identification of those who could benefit from a brief intervention or referral for a reduction in alcohol-related injuries.  相似文献   
996.
997.
BACKGROUND: We recently reported the prevalence of aortic regurgitation (AR) by Doppler echocardiography (echo) in obese subjects to be higher than in some previous reports. OBJECTIVE: To describe the prevalence of AR in an obese population not taking anorexigens as a function of demographic characteristics, cardiovascular risk factors, and other potential predictors. METHODS: In 539 adult subjects, cardiovascular status was evaluated by medical history, physical examination, and Doppler echocardiograms performed according to a standardized imaging protocol. Echocardiographic readers were blinded as to each subject's medical and medication histories. Associations of AR with demographic and comorbid factors were examined. RESULTS: Subjects had a mean (+/- SD) body mass index (BMI) of 35 +/- 7 kg/m2, and were predominantly white (87.6%), females (74%), with a mean age of 47 +/- 12 years. AR by Food and Drug Administration criteria (> or =mild) was present in 4.1% of the subjects. Covariates significantly associated with AR were increasing age (P < 0.001), presence of a history of hypertension (P = 0.001), left ventricular (LV) internal dimensions (P < 0.005), and tricuspid and mitral regurgitation grade (P < 0.001). CONCLUSIONS: Clinical and Doppler echo evaluation of a large, predominantly obese, adult population revealed that AR was more prevalent than in some previous reports and was highly correlated with increased age, presence of a history of hypertension, LV internal dimensions, tricuspid and mitral regurgitation.  相似文献   
998.
OBJECTIVE: To investigate whether endothelin and aldosterone participate in the increased prevalence and severity of nephrosclerosis in human low-renin hypertension, analogous to observations in experimental hypertension. DESIGN: Comparison of endothelin, aldosterone and their relationships with proteinuria, in hypertensive patients with high aldosterone : renin ratios (HARR group, n = 14) or normal aldosterone : renin ratios (NARR group, n = 15). METHODS: Urine protein and radioimmunoassay measurements of plasma renin activity, endothelin and aldosterone were carried out in individuals taking their usual diet, and after salt loading and salt depletion. RESULTS: Compared with the NARR group, patients in the HARR group had higher blood pressure, greater salt sensitivity of their blood pressure, significantly greater urine protein and lower serum potassium concentrations, lower renin activities [0.14 +/- 0.03 ng AngiotensinI (AI)/l per s compared with 0.76 +/- 0.16 ng AI/l per s; P < 0.005], blunted renin-aldosterone responses to salt loading and salt depletion, enhanced catecholamine responses to salt depletion, and increased plasma endothelin (5.1 +/- 0.5 fmol/ml compared with 3.7 +/- 0.3 fmol/ml; P < 0.03). In the HARR group, endothelin and aldosterone concentrations were highly correlated, and both correlated with blood pressure and urine protein. In contrast, in the NARR group, endothelin and aldosterone did not correlate between them or with blood pressure, and only endothelin, not aldosterone, correlated with urine protein. Multivariate regression confirmed that the interaction between aldosterone and endothelin was the major predictor of urine protein in the HARR group (r = 0.442), whereas endothelin, renin and their interaction were predictors in the NARR group (r = 0.467). CONCLUSIONS: Our results concur with experimental evidence for participation of endothelin in renal damage of angiotensin-dependent hypertension and for that of an endothelin-aldosterone interaction in low-renin hypertension. We propose that combined pharmacological antagonism of endothelin and aldosterone may confer renal protection beyond blood pressure reduction in patients with low-renin hypertension, a population at high risk for hypertensive nephrosclerosis.  相似文献   
999.
Although antihistamine-decongestant combinations are frequently used for allergic rhinitis, published data about the onset of action of these combination agents are limited. This randomized, double-blind, placebo-controlled, parallel-group study investigated the onset of action, efficacy, and safety of fexofenadine HCl 60 mg/pseudoephedrine HCl 120 mg or placebo in patients with moderate-to-severe seasonal allergic rhinitis in an allergen exposure unit. Assessments included major symptom complex (MSC) score (sum of sneezing, itchy nose, runny nose, watery eyes, itchy eyes, itchy ears/throat, and stuffy nose), and total symptom complex (TSC) score (MSC symptoms plus nose blows, sniffles, postnasal drip, and cough). Onset of action was defined as the first time that two consecutive, statistically significant absolute changes in MSC scores from baseline were achieved for study drug relative to placebo. The onset of action for the combination was 60 minutes (mean absolute MSC change from baseline: -6.9 +/- 0.3 for the combination compared with -5.9 +/- 0.3 for placebo from a baseline of 17.0 and 16.8, respectively; p < 0.05) for the modified intention-to-treat population (n = 486). Reductions in absolute MSC scores were significantly greater with the combination than placebo at all subsequent time points (p < 0.01). The combination resulted in significantly greater reductions compared with placebo for percent MSC, absolute TSC, and percent TSC scores at 60 minutes postdose (all p < 0.05) and throughout the study (all p < 0.05). The incidence of adverse events was 1.6 and 3.3% for the combination and placebo, respectively. In conclusion, fexofenadine HCl 60 mg/pseudoephedrine HCl 120 mg is effective in the treatment of patients with moderate-to-severe seasonal AR, with an onset of action of 60 minutes and a good safety profile.  相似文献   
1000.
BACKGROUND: Minimally invasive off-pump pulmonary vein isolation to cure paroxysmal atrial fibrillation (PAF) may be an alternative to percutaneous catheter-based procedures. METHODS: Three patients with highly symptomatic lone PAF refractory to medical treatment and having undergone unsuccessful catheter-based ablation underwent pulmonary vein isolation using the Cardioblate BP device with a minimally invasive approach. RESULTS: There were no complications and all patients were discharged in sinus rhythm. Mean ablation time per lesion was 15.2 sec and mean operation time was 118 min. CONCLUSIONS: Irrigated bipolar radiofrequency ablation of the pulmonary veins is safe and can be performed off-pump in a minimally invasive manner.  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