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   2424篇
  免费   191篇
  国内免费   8篇
耳鼻咽喉   20篇
儿科学   70篇
妇产科学   41篇
基础医学   331篇
口腔科学   22篇
临床医学   210篇
内科学   486篇
皮肤病学   48篇
神经病学   116篇
特种医学   168篇
外科学   364篇
综合类   100篇
一般理论   2篇
预防医学   116篇
眼科学   55篇
药学   290篇
中国医学   11篇
肿瘤学   173篇
  2023年   13篇
  2022年   38篇
  2021年   71篇
  2020年   43篇
  2019年   54篇
  2018年   57篇
  2017年   49篇
  2016年   80篇
  2015年   66篇
  2014年   89篇
  2013年   135篇
  2012年   184篇
  2011年   192篇
  2010年   123篇
  2009年   73篇
  2008年   158篇
  2007年   139篇
  2006年   136篇
  2005年   129篇
  2004年   130篇
  2003年   104篇
  2002年   76篇
  2001年   35篇
  2000年   34篇
  1999年   40篇
  1998年   20篇
  1997年   15篇
  1996年   13篇
  1995年   10篇
  1994年   10篇
  1993年   14篇
  1992年   24篇
  1991年   32篇
  1990年   22篇
  1989年   17篇
  1988年   10篇
  1987年   10篇
  1986年   11篇
  1985年   12篇
  1983年   11篇
  1982年   13篇
  1981年   12篇
  1980年   7篇
  1979年   8篇
  1978年   8篇
  1976年   8篇
  1974年   10篇
  1972年   10篇
  1970年   7篇
  1969年   9篇
排序方式: 共有2623条查询结果,搜索用时 15 毫秒
101.
Fracture Risk Assessment (FRAX) tools are calibrated from country‐specific fracture epidemiology. Although hip fracture data are usually available, data on non‐hip fractures for most countries are often lacking. In such cases, rates are often estimated by assuming similar non‐hip to hip fracture ratios from historical (1987 to 1996) Swedish data. Evidence that countries share similar fracture ratios is limited. Using data from Manitoba, Canada (2000 to 2007, population 1.2 million), we identified 21,850 incident major osteoporotic fractures (MOF) in men and women aged >50 years. Population‐based age‐ and sex‐specific ratios of clinical vertebral, forearm, and humerus fractures to hip fractures were calculated, along with odds ratios (ORs) and 95% confidence intervals (CIs). All ratios showed decreasing trends with increasing age for both men and women. Men and women showed similar vertebral/hip fracture ratios (all p > 0.1, with ORs 0.86 to 1.25). Forearm/hip and humerus/hip fracture ratios were significantly lower among men than women (forearm/hip ratio: p < 0.01 for all age groups, with ORs 0.29 to 0.53; humerus/hip ratio: p < 0.05 for all age groups [except 80 to 84 years] with ORs 0.46 to 0.86). Ratios for any MOF/hip fracture were also significantly lower among men than women in all but two subgroups (p < 0.05 for all age groups [except 80 to 84 and 90+ years] with ORs 0.48 to 0.87). Swedish vertebral/hip fracture ratios were similar to the Canadian fracture ratios (within 7%) but significantly lower for other sites (men and women: 46% and 35% lower for forearm/hip ratios, 19% and 15% lower for humerus/hip ratios, and 19% and 23% lower for any MOF/hip ratios). These differences have implications for updating and calibrating FRAX tools, fracture risk estimation, and intervention rates. Moreover, wherever possible, it is important that countries try to collect accurate non‐hip fracture data. © 2014 American Society for Bone and Mineral Research  相似文献   
102.
It is unknown how responsive the Fracture Risk Assessment (FRAX) tool is to osteoporosis treatment (OTX) or whether it can serve as a target for “goal‐directed” treatment. We studied 11,049 untreated women aged ≥50 years undergoing baseline and follow‐up DXA examinations in Manitoba, Canada. We identified clinical risk factors, intervening OTX based on medication possession ratios (MPR), and incident fractures. FRAX scores for major osteoporotic and hip fractures were computed for each scan using the most current (updated) FRAX inputs. Over 4 years, median FRAX scores showed an increase of 1.1% for major fractures and 0.3% for hip fractures, including women highly adherent to OTX (0.6% and 0.1% increases). Few (2.2%) highly adherent women had a decrease in major fracture probability exceeding 4%, whereas 9.0% had a decrease in hip fracture probability exceeding 1%. Compared with untreated women, OTX was associated with a higher dose‐dependent likelihood of attenuating the expected increase in major fracture risk: adjusted odds ratios (aOR) 2.3 (95% confidence interval [CI] 1.8–2.9) for MPR <0.50; 7.3 (95% CI 5.6–9.6) for MPR 0.50–0.79; and 12.0 (95% CI 9.5–15.2) for MPR ≥0.80. In the 4 years after the second DXA scan, 620 (6%) women had major fractures (152 hip fractures). FRAX scores were strongly predictive of incident major fractures (adjusted hazard ratios [aHR] per SD increase in FRAX 1.8, 95% CI 1.7–1.9) and hip fractures (aHR per SD 4.5, 95% CI 3.7–5.7); however, change in FRAX score was not independently associated with major fracture (p = 0.8) or hip fracture (p = 0.3). In conclusion, FRAX scores slowly increased over time, and this increase was attenuated but not prevented by treatment. Few women had meaningful reductions in FRAX scores, and change in FRAX score did not independently predict incident fracture, suggesting that FRAX with BMD is not responsive enough to be used as a target for goal‐directed treatment. © 2014 American Society for Bone and Mineral Research.  相似文献   
103.

Summary

Most patients are not treated for osteoporosis after their fragility fracture “teachable moment.” Among almost 400 consecutive wrist fracture patients, we determined that better-than-average osteoporosis knowledge (adjusted odds?=?2.6) and BMD testing (adjusted odds?=?6.5) were significant modifiable facilitators of bisphosphonate treatment while male sex, working outside the home, and depression were major barriers.

Introduction

In the year following fragility fracture, fewer than one quarter of patients are treated for osteoporosis. Although much is known regarding health system and provider barriers and facilitators to osteoporosis treatment, much less is understood about modifiable patient-related factors.

Methods

Older patients with wrist fracture not treated for osteoporosis were enrolled in trials that compared a multifaceted intervention with usual care controls. Baseline data included a test of patient osteoporosis knowledge. We then determined baseline factors that independently predicted starting bisphosphonate treatment within 1 year.

Results

Three hundred seventy-four patients were enrolled; mean age 64 years, 78 % women, 90 % white, and 54 % with prior fracture. Within 1 year, 86 of 374 (23 %) patients were treated with bisphosphonates. Patients who were treated had better osteoporosis knowledge at baseline (70 % correct vs 57 % for untreated, p?Conclusions The most important modifiable facilitators of osteoporosis treatment in patients with fracture were knowledge and BMD testing. Specifically targeting these two patient-level factors should improve post-fracture treatment rates.  相似文献   
104.

Summary

In an observational study population of 62,413 individuals (6,455 [10 %] with diabetes), diabetes was independently associated with major osteoporotic fractures (MOFs) but did not significantly modify the effect of FRAXTM risk factors or prior fracture site. However, the presence of diabetes exerted a much stronger effect on hip fracture risk in younger versus older individuals.

Introduction

Diabetes mellitus increases fracture risk independent of risk factors that comprise the WHO FRAXTM tool. We explored whether diabetes modifies the effect of FRAX clinical risk factors on MOF and hip fracture risk.

Methods

Using a registry of clinical dual-energy X-ray absorptiometry (DXA) results for Manitoba, Canada, we identified women and men aged 40 years and older undergoing baseline DXA in 1996–2011. Health services data were used to identify diabetes diagnosis, FRAX risk factors and incident fractures using previously validated algorithms. Prior fracture was stratified as clinical vertebral, hip, humerus, forearm, pelvis and ‘other’. Cox proportional hazards models were used to test for statistical interactions of diabetes with FRAX clinical risk factors and prior fracture site.

Results

During a mean follow-up of 6 years, there were 4,218 MOF and 1,108 hip fractures. Diabetes was a significant independent risk factor for MOF adjusted for FRAX risk factors including bone mineral density (BMD) (adjusted hazard ratio [aHR] 1.32 [95 % confidence interval (CI) 1.20–1.46]). No significant interactions of FRAX risk factors or prior fracture site with diabetes were identified in analyses of MOF. For predicting hip fractures, age significantly modified the effect of diabetes (aHR age <60, 4.67 [95 % CI 2.76–7.89], age 60–69, 2.68 [1.77–4.04], age 70–79, 1.57 [1.20–2.04], age >80, 1.42 [1. 10–1.99]; pinteraction <0.001).

Conclusions

Diabetes is an independent risk factor for MOFs and does not significantly modify the effect of FRAX risk factors or prior fracture site. However, diabetes exerts a much stronger effect on hip fracture risk in younger than older individuals which needs to be considered in hip fracture prediction.  相似文献   
105.
106.

Background

Gloriosa superba produces an array of alkaloids including colchicine, a compound of interest in the treatment of various diseases. The tuber of Gloriosa superba is a rich source of colchicine which has shown anti-gout, anti-inflammatory, and anti-tumor activity. However, this promising compound remains expensive and Gloriosa superba is such a good source in global scale. Increase in yield of naturally occurring colchicine is an important area of investigation.

Materials and Methods

The effects of inoculation by four arbuscular mycorrhizal (AM), fungi, Glomus mossae, Glomus fasciculatum, Gigaspora margarita and Gigaspora gilmorei either alone or supplemented with P-fertilizer, on colchicine concentration in Gloriosa superba were studied. The concentration of colchicine was determined by high-performance thin layer chromatography.

Results

The four fungi significantly increased concentration of colchicine in the herb. Although there was significant increase in concentration of colchicine in non-mycorrhizal P-fertilized plants as compared to control, the extent of the increase was less compared to mycorrhizal plants grown with or without P-fertilization. This suggests that the increase in colchicine concentration may not be entirely attributed to enhanced P-nutrition and improved growth. Among the four AM fungi Glomus mossae was found to be best. The total colchicine content of plant (mg / plant) was significantly high in plants inoculated with Glomus mossae and 25 mg kg−1phosphorus fertilizer (348.9 mg /plant) while the control contain least colchicine (177.87 mg / plant).

Conclusion

The study suggests a potential role of AM fungi in improving the concentration of colchicine in Gloriosa superba tuber.  相似文献   
107.
108.
Alveolar soft part sarcoma is a rare soft tissue tumor with uncertain histogenesis. It is a slow growing tumor with a high rate of metastasis. The tumor is not easily identified as clinical symptoms are not pronounced. The retroperitoneum is a rare location of tumor, with a few cases published in literature. Surgical excision is the mainstay of treatment. Here we describe a rare case of a large retroperitoneal Alveolar soft part sarcoma in a young female with radiological and histopathological findings.  相似文献   
109.
110.
Increased hepatic lipid content and decreased insulin sensitivity have critical roles in the development of cardiometabolic diseases. Therefore, our objective was to investigate the dose-response effects of consuming high fructose corn syrup (HFCS)-sweetened beverages for two weeks on hepatic lipid content and insulin sensitivity in young (18–40 years) adults (BMI 18–35 kg/m2). In a parallel, double-blinded study, participants consumed three beverages/day providing 0% (aspartame: n = 23), 10% (n = 18), 17.5% (n = 16), or 25% (n = 28) daily energy requirements from HFCS. Magnetic resonance imaging for hepatic lipid content and oral glucose tolerance tests (OGTT) were conducted during 3.5-day inpatient visits at baseline and again at the end of a 15-day intervention. During the 12 intervening outpatient days participants consumed their usual diets with their assigned beverages. Significant linear dose-response effects were observed for increases of hepatic lipid content (p = 0.015) and glucose and insulin AUCs during OGTT (both p = 0.0004), and for decreases in the Matsuda (p = 0.0087) and Predicted M (p = 0.0027) indices of insulin sensitivity. These dose-response effects strengthen the mechanistic evidence implicating consumption of HFCS-sweetened beverages as a contributor to the metabolic dysregulation that increases risk for nonalcoholic fatty liver disease and type 2 diabetes.  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