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   4295篇
  免费   219篇
  国内免费   61篇
耳鼻咽喉   89篇
儿科学   193篇
妇产科学   206篇
基础医学   340篇
口腔科学   114篇
临床医学   362篇
内科学   1312篇
皮肤病学   34篇
神经病学   255篇
特种医学   168篇
外科学   635篇
综合类   102篇
一般理论   1篇
预防医学   167篇
眼科学   187篇
药学   230篇
中国医学   18篇
肿瘤学   162篇
  2024年   5篇
  2023年   37篇
  2022年   69篇
  2021年   130篇
  2020年   66篇
  2019年   94篇
  2018年   109篇
  2017年   89篇
  2016年   104篇
  2015年   151篇
  2014年   169篇
  2013年   224篇
  2012年   335篇
  2011年   328篇
  2010年   192篇
  2009年   168篇
  2008年   311篇
  2007年   361篇
  2006年   305篇
  2005年   322篇
  2004年   209篇
  2003年   198篇
  2002年   166篇
  2001年   65篇
  2000年   59篇
  1999年   49篇
  1998年   20篇
  1997年   28篇
  1996年   14篇
  1995年   18篇
  1994年   11篇
  1993年   8篇
  1992年   13篇
  1991年   20篇
  1990年   18篇
  1989年   18篇
  1988年   16篇
  1987年   11篇
  1986年   8篇
  1985年   13篇
  1984年   7篇
  1983年   8篇
  1981年   3篇
  1980年   4篇
  1979年   4篇
  1978年   2篇
  1973年   3篇
  1971年   2篇
  1931年   1篇
  1929年   1篇
排序方式: 共有4575条查询结果,搜索用时 15 毫秒
121.

Background:

Randomized trials have established the benefit of medical therapy and revascularization in the treatment of acute myocardial infarction (MI). Cancer and cardiovascular disease are the 2 most common diseases worldwide. In clinical practice, cancer patients are frequently afflicted with MI. The benefit of medical and/or revascularization therapy in the cancer population with MI is less well known.

Hypothesis:

Medical and revascularization therapy reduces mortality in cancer patients with MI.

Methods:

After approval by the institutional review board, we retrospectively reviewed all patients with a discharge diagnosis of acute MI who were admitted to the University of Texas MD Anderson Cancer Center between December 2000 and October 2006 and evaluated the association between cardiac treatments with survival outcomes.

Results:

A total of 456 patients with a discharge diagnosis of acute MI were identified and included in the study, of which 386 had non–ST‐segment elevation MI (NSTEMI) and 70 had ST‐segment elevation MI (STEMI). Compared with patients with NSTEMI, patients who had STEMI were more often prescribed aspirin (66% vs 43%; P = 0.004), β‐blockers (61% vs 46%; P = 0.018), and thrombolytic therapy (9% vs 0.3%; P = 0.0001). In the multivariable analysis, aspirin use was associated with a 23% decreased risk of death (hazard ratio [HR]: 0.77, 95% confidence interval [CI]: 0.60‐0.98, P = 0.033) and β‐blocker use was associated with a 36% decreased risk of death (HR: 0.64, 95% CI: 0.51–0.81, P = 0.0002). Statins (HR: 0.82, P = 0.18) and catheter‐based revascularization (HR: 0.57, P = 0.09) did not have an impact on the risk of death. Compared with patients with limited cancer, advanced cancer patients were twice as likely to die (HR: 2.12, 95 CI: 1.47–3.04, P < 0.0001). Previous chemotherapy (P = 0.005) and chest radiotherapy (P = 0.017) were associated with increased 1‐year mortality, whereas hyperlipidemia (P = 0.018) was protective.

Conclusions:

In this study of cancer patients with MI, medical therapy with aspirin and β‐blockers was associated with improved survival. The authors have no funding, financial relationships, or conflicts of interest to disclose.  相似文献   
122.
In the Turkish health care system and hospitals it is very common to witness role conflict and ambiguity among health care personnel. Often this is due to a lack of clarity as to what is expected and required of them. The unfortunate and unavoidable result is a high level of burnout caused by uncertain working conditions in Turkish hospitals. The objectives of this study were to determine the level of role conflict, role ambiguity, and burnout of physicians and nurses working in hospitals, to see the relationship between role conflict, ambiguity and burnout level, to reveal the effects of organisational and indvidual characteristics on the burnout level of physicians and nurses. The study was conducted in three hospitals attached to the Ministry of Health (MoH) of Turkey. 149 nurses and 83 physicians were included in the sample of this study although several efforts of reminders and additional visits to the hospitals to increase the response rate. Structural Equational Modelling (SEM) was chosen to estimate the effects of certain selected individual and organisational variables that were determined by a set of correlation and biovariate analyses on role conflict and ambiguity as well as the burnout level. The SEM results showed that working in surgical units, having less working experience and choosing the profession unwillingly had significant and negative direct effects on the burnout level of the physicians and nurses in the sample of this study. Decreasing the level of role conflict and ambiguity would serve to decrease the level of burnout. In order to decrease the level of role conflict, ambiguity, and burn out level for nurses and physicans, serious efforts must be made to clarify role definitions, increase resources, and employ conflict management methods.  相似文献   
123.
Strontium ranelate is claimed to be related with increased risk of thromboembolic events. No explanation of this increased incidence of thromboembolism has been identified. However, growing evidence has clearly demonstrated the involvement of blood rheology in any thrombotic process. The aim of this study was to assess hemorheological changes with strontium ranelate treatment in elderly women with osteoporosis. This study was designed in a prospective manner. Twenty-two elderly women diagnosed with osteoporosis were included. During a 2-month treatment period, participants received strontium ranelate 2 g/day. Hemorheological parameters including erythrocyte deformability, erythrocyte aggregation and plasma viscosity were measured before and after 2 months therapy with strontium ranelate. The median age of the patients was 70.0 (range = 65-80) years. After 60 days of treatment, there was no statistically significant change in hemorheological parameters. None of the subjects developed clinical venous thromboembolic event (VTE) during the 2-month period of strontium ranelate treatment. Our study demonstrated that in elderly women, treatment of osteoporosis with strontium ranelate did not change hemorheological parameters over 2 months of time. However, its long-term effects on hemorheologic parameters should be evaluated further with a larger sample.  相似文献   
124.
Cardiovascular disease (CVD) and OP are common age-related conditions. In both cross-sectional and longitudinal epidemiologic studies, low bone mass has been related to increased frequency of CVD. But available data in geriatric population is limited. In this study we aimed to seek the possible relationship between CAD and low bone mineral density (BMD) in a large number of geriatric patients. A total of 2235 patients aged 65 years or more were included in this cross-sectional study. All patients underwent a complete geriatric assessment and evaluated for CAD and cardiovascular risk factors. BMD was measured by dual-energy X-ray absorptiometry at the lumbar spine (L1-L4) and femoral neck. BMD results were classified into three groups; normal (T-score: ≥-1.0×S.D.), osteopenia (T-score between -1.0 and -2.5×S.D.), and OP (T-score: ≤-2.5×S.D.). CAD was present in 397 (29.7%) of 1335 patients with OP, in 199 (27.4%) of 726 patients with osteopenia and in 34 (19.5%) of 174 patients with normal BMD. Multivariate regression analysis revealed that presence of OP or osteopenia increased the prevalence of CAD as an independent correlate (OR=1.643; 95% CI=1.068-2.528, p=0.030). This study highlights the need for careful evaluation of elderly patients with low BMD for possible CAD.  相似文献   
125.
Previous studies showed oxidative stress had an important impact on osteoclastic and osteoblastic functions. Oxidative stress or low levels of antioxidants are supposed to reduce BMD and cause osteoporosis. hcy, gamma glutamyltransferase (GGT), uric acid, albumin and total bilirubin are simple laboratory parameters that are related with oxidative stress. In this study we compare the serum hcy and antioxidant levels in patients with osteoporosis, osteopenia and control subjects. A total of 2190 elderly persons (1348 patients with osteoporosis, 643 patients with osteopenia and 199 control subjects) who were referred to the outpatient clinic of the Department of Internal Medicine, Division of Geriatric Medicine at Hacettepe University Hospital for comprehensive geriatric assessment were included in this cross-sectional study. Mean age of subjects were 72.30±6.34 in osteoporosis group, 71.92±6.90 in osteopenia and 71.86±5.88 in control group (p: 0.260). Multivariate regression analysis revealed that hypertension (HT) (OR: 0.675, 95% CI: 0.534-0.854, p: 0.001), diabetes mellitus (DM) (OR: 1.669, 95% CI: 1.301-2.142, p: <0.001), age (OR: 1.025, 95% CI: 1.006-1.044, p: 0.009), male gender (OR: 0.451, 95% CI: 0.358-0.569, p<0.001), uric acid (OR: 0.893, 95% CI: 0.837-0.952, p: 0.001), hcy (OR: 1.042, 95% CI: 1.023-1.061, p<0.001), albumin (OR: 0.521, 95% CI: 0.376-0.724, p<0.001), GGT (OR: 1.010, 95% CI: 1.003-1.017, p: 0.003), creatinine (OR: 0.630, 95% CI: 0.459-0.864, p: 0.004) were independent variables predicting the occurrence of osteoporosis. This study shows there is an imbalance between natural antioxidative and oxidative markers in patients with osteoporosis. Higher serum uric acid and albumin levels are associated with a lower prevalence of osteoporosis whereas higher hcy and GGT levels are associated lower BMD and higher osteoporosis prevalence.  相似文献   
126.
127.
128.
129.
130.
Tekin G  Sivri N  Tekin YK  Topal E  Erbay AR  Yetkin E 《Angiology》2012,63(7):552-555
We assessed the clinical echocardiograhic, hematological, and biochemical parameters in patients with dilated cardiomyopathy (DCMP) and control individuals mainly focusing on the mean platelet volume (MPV) in terms of DCMP and left ventricle (LV) thrombus formation. Consecutive patients (n = 251) with DCMP and 266 patients without DCMP were studied. Mean platelet volume was significantly greater in patients with DCMP than in control patients (P < .05 for all comparisons). Comparing DCMP patients with LV thrombus (19 patients, 8%) and without LV thrombus (232 patients, 92%) showed that the prevalence of smokers was significantly higher and ejection fraction was significantly lower in patients with LV thrombus. We have shown that patients with DCMP have significantly higher MPV suggesting more platelet activation and the MPV of patients with DCMP and LV thrombus is comparable to those of patients without LV thrombus.  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