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   1969篇
  免费   173篇
  国内免费   3篇
耳鼻咽喉   6篇
儿科学   70篇
妇产科学   25篇
基础医学   367篇
口腔科学   19篇
临床医学   251篇
内科学   340篇
皮肤病学   16篇
神经病学   208篇
特种医学   37篇
外科学   146篇
综合类   26篇
一般理论   4篇
预防医学   236篇
眼科学   27篇
药学   213篇
中国医学   1篇
肿瘤学   153篇
  2023年   22篇
  2022年   25篇
  2021年   40篇
  2020年   33篇
  2019年   34篇
  2018年   48篇
  2017年   35篇
  2016年   43篇
  2015年   43篇
  2014年   51篇
  2013年   76篇
  2012年   119篇
  2011年   127篇
  2010年   65篇
  2009年   67篇
  2008年   88篇
  2007年   109篇
  2006年   92篇
  2005年   92篇
  2004年   93篇
  2003年   95篇
  2002年   103篇
  2001年   37篇
  2000年   48篇
  1999年   55篇
  1998年   21篇
  1997年   27篇
  1996年   34篇
  1995年   34篇
  1994年   20篇
  1993年   19篇
  1992年   37篇
  1991年   22篇
  1990年   22篇
  1989年   25篇
  1988年   17篇
  1987年   16篇
  1986年   11篇
  1985年   9篇
  1984年   8篇
  1983年   25篇
  1982年   7篇
  1981年   13篇
  1980年   7篇
  1979年   9篇
  1977年   9篇
  1975年   11篇
  1974年   12篇
  1972年   8篇
  1971年   8篇
排序方式: 共有2145条查询结果,搜索用时 0 毫秒
31.
Objectives: To compare indicators relating to aging and health among veterans and non-veterans, and identify factors associated with subjective wellbeing (SWB) of older New Zealand veterans.

Methods: Self-reported data were obtained from participants in a longitudinal cohort study of New Zealand older adults. Responses from 352 veterans and 1500 non-veterans (age range of 55–86 and gender matched) were selected as a comparison group on indicators related to health and aging. The association of these indicators with veterans’ SWB were assessed using hierarchical regression.

Results: Apart from being older, smoking more, and having more chronic conditions, veterans did not differ from non-veterans on indicators of health and wellbeing. Mental health, physical health, purpose in life, housing satisfaction, and capabilities (choice and freedom) accounted for a significant amount of variance in veterans’ SWB.

Conclusion: Our results suggest that older veterans do not differ greatly on indices of health and aging from their non-veteran peers. Results support previous findings that lower mental and physical health is associated with lower SWB for veterans. Building upon prior findings, the current results demonstrate that interventions focusing on enhancing a sense of purpose in life, supporting one's capability to achieve, and strengthening social and physical environment through social connectedness, may serve as protective factors for SWB in veterans.  相似文献   

32.
Size at birth and carotid atherosclerosis in later life   总被引:4,自引:0,他引:4  
Several studies have shown that low birthweight is associated with a higher risk of stroke and coronary heart disease in later life. Increased atherogenesis may be one underlying mechanism, but few studies have examined this directly. We used duplex ultrasonography to assess the extra-cranial carotid arteries of 389 elderly men and women born and still living in Sheffield, UK, whose recorded birth measurements were available. Men and women who had weighed 6.5 lbs or less at birth had a higher risk of having carotid stenosis >30% than those who weighed over 7.5 lbs, but this trend was not statistically significant (OR 1.8, 95% CI 1.0-3.3). Women who had been lighter or who had a smaller head circumference at birth tended to have an increased intima-media thickness, but these relations ceased to be statistically significant after adjustment for gestational age and cardiovascular risk factors. In men, by contrast, an increased intima-media thickness was associated with having been heavier at birth (P=0.049) or having had a larger abdominal circumference at birth (P=0.040), after adjustment for gestational age and cardiovascular risk factors. These results provide little evidence that impaired fetal growth increases susceptibility to atherogenesis.  相似文献   
33.
Aim: To present a novel approach to treatment of dural carotid-cavernous fistulas via the medial ophthalmic vein.

Design: Retrospective case series.

Material and Methods: In this retrospective case series, we present 2 patients (3 eyes) with Type C dural CCFs, who had failed cannulation via the conventional transfemoral route and the transorbital superior ophthalmic vein approach. They subsequently underwent CCF occlusion via an anterior orbital approach through the medial ophthalmic veins, at the Department of Ophthalmology, National University Hospital Singapore. CCF occlusion was confirmed intraoperatively using angiography. Both patients were evaluated postoperatively for best-corrected visual acuity and resolution of clinical signs and symptoms.

Results: Successful occlusion of CCFs via the medial ophthalmic veins were achieved in all three orbits, with excellent visual and cosmetic outcomes postoperatively.

Conclusion: Dural CCFs may potentially lead to severe visual dysfunction and should be diagnosed and treated promptly. When all venous routes have been exhausted, the transorbital approach via the medial ophthalmic vein remains an excellent and viable alternative to access the fistula. Close cooperation between the orbital, anesthetic and radiological teams is essential in ensuring success of the operation.  相似文献   

34.
Tetanus is a preventable disease that continues to affect people in both developing and developed countries. The aim of the present study was to evaluate the immunity profile to tetanus in patients with Type II diabetes mellitus (DM) and to compare them with healthy controls. The tetanus antitoxin levels in 310 diabetic patients (104 males and 206 females) and in 200 healthy controls (72 males and 128 females) were measured by ELISA (Virotech, Germany). The mean antitoxin concentration in patient and control groups were 0.8238+/-1.61 and 0.9978+/-1.49 IU/ml, respectively. There was a statistically significant difference between the two groups (z=-3.520, P=.0001 and odds ratio was 2.367). There was a definitive inverse correlation between the duration of diabetes and tetanus antibody titers (Spearman's correlation analysis, r=-.155, P=.006). A gender-dependent difference in the susceptibility to tetanus was present in the diabetic group with antibody titers being significantly higher in males compared with females (z=-2.267, P=.023). For both of control (chi(2)=20.207, P=.003) and patient (chi(2)=43.532, P=.0001) groups, there was a significant inverse correlation between the tetanus immunity levels and age. Statistically, a significant drop in antibody titers of both groups was found as the period past from the last immunization increased (Pearson correlation analysis: for patient group r=-.364, P=.0001; for control group r=-.143, P=.044). The tetanus antitoxin levels were significantly increased in individuals who had primary immunization during childhood (for patient group chi(2)=17.191, P=.0001; for control group chi(2)=9.911, P=.007). A significant reduction in the level of antitoxin immunity to tetanus in association with an increased susceptibility to infections in patients with diabetes may implicate the need for improving vaccination rates in this patient group.  相似文献   
35.
36.
We have characterized plasma pharmacokinetics in 30 patients receiving mitomycin C (mitomycin) in doses ranging from 6 to 20 mg/m2 by iv bolus injection, either alone or in combination with other chemotherapeutic drugs. Plasma elimination of the drug was described by a two-compartment model in all but three cases, giving mean values for alpha-half-life of 8.2 mins, beta-half-life of 51.8 mins, and total body clearance of 332.9 ml/min/m2. The mean urinary excretion was 8.1% of the total dose administered. We did not detect alterations in pharmacologic parameters related to liver dysfunction, dose of mitomycin, and concomitant administration of other cytotoxic drugs.  相似文献   
37.
38.

Background

There is no established primary care solution for the rapidly increasing numbers of severely obese people with body mass index (BMI) > 40 kg/m2.

Aim

This programme aimed to generate weight losses of ≥15 kg at 12 months, within routine primary care.

Design and setting

Feasibility study in primary care.

Method

Patients with a BMI ≥40 kg/m2 commenced a micronutrient-replete 810–833 kcal/day low-energy liquid diet (LELD), delivered in primary care, for a planned 12 weeks or 20 kg weight loss (whichever was the sooner), with structured food reintroduction and then weight-loss maintenance, with optional orlistat to 12 months.

Result

Of 91 patients (74 females) entering the programme (baseline: weight 131 kg, BMI 48 kg/m2, age 46 years), 58/91(64%) completed the LELD stage, with a mean duration of 14.4 weeks (standard deviation [SD] = 6.0 weeks), and a mean weight loss of 16.9 kg (SD = 6.0 kg). Four patients commenced weight-loss maintenance omitting the food-reintroduction stage. Of the remaining 54, 37(68%) started and completed food reintroduction over a mean duration of 9.3 weeks (SD = 5.7 weeks), with a further mean weight loss of 2.1 kg (SD = 3.7 kg), before starting a long-term low-fat-diet weight-loss maintenance plan. A total of 44/91 (48%) received orlistat at some stage. At 12 months, weight was recorded for 68/91 (75%) patients, with a mean loss of 12.4 kg (SD = 11.4 kg). Of these, 30 (33% of all 91 patients starting the programme) had a documented maintained weight loss of ≥15 kg at 12 months, six (7%) had a 10–15 kg loss, and 11 (12%) had a 5–10 kg loss. The indicative cost of providing this entire programme for wider implementation would be £861 per patient entered, or £2611 per documented 15 kg loss achieved.

Conclusion

A care package within routine primary care for severe obesity, including LELD, food reintroduction, and weight-loss maintenance, was well accepted and achieved a 12-month-maintained weight loss of ≥15 kg for one-third of all patients entering the programme.  相似文献   
39.
Recent advances in technology have given rise to novel methods of delivering support to smokers wanting to quit. Mobile phone text messaging permits the delivery of quitting advice at any time, with little effort and at minimal cost. We examined smokers' attitudes toward text messaging as a tool to facilitate smoking cessation as well as preferences for message content and text delivery. Six focus groups were conducted from a total of 24 participants, with additional information obtained via paper questionnaire. Interaction with the text messaging system, tailoring message content and delivery, highlighting the positive effects of quitting, and offering encouragement by text were considered important features of a text support program. Future text messaging interventions may benefit from these findings.  相似文献   
40.
Myocardial fibrosis is a risk factor for sudden cardiac death in hypertrophic cardiomyopathy (HCM) and is conventionally identified by cardiac magnetic resonance imaging (CMR) using late gadolinium enhancement (LGE). This study evaluates utility of a novel 16-segment CMR feature tracking (CMR-FT) technique for measuring left ventricular (LV) strain (S) and strain rate (SR) on non-contrast cine images to detect myocardial fibrosis in pediatric HCM. We hypothesized that CMR-FT-derived S and SR will accurately differentiate HCM patients with and without myocardial fibrosis. Consecutive children with HCM who underwent CMR with LGE at our institution from 2006 to 2014 were included. Global and regional longitudinal, radial and circumferential S and SR of the LV in 2D and 3D were obtained using a CMR-FT software. Comparisons were made between HCM patients with (+LGE) and without (?LGE) delayed enhancement. Of the 29 HCM patients (mean age 13.5 ± 6.1 years; 52 % males), 11 (40 %) patients (mean age 17.5 ± 8.4 years) had +LGE. Global longitudinal, circumferential and radial S and SR were lower in +LGE compared to ?LGE patients, in both 2D and 3D. Regional analysis revealed lower segmental S and SR in the septum with fibrosis compared to free wall without fibrosis. A global longitudinal S of ≤ ?12.8 had 91 % sensitivity and 89 % specificity for detection of LGE. In pediatric HCM patients with myocardial fibrosis, global LV longitudinal, circumferential and radial S and SR were reduced, specifically in areas of fibrosis. A global longitudinal S of ≤ ?12.8 detected patients with fibrosis with high degree of accuracy. This novel CMR-FT technique may be useful to identify myocardial fibrosis and risk-stratify pediatric HCM without use of contrast agents.  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