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   3845篇
  免费   283篇
  国内免费   40篇
耳鼻咽喉   35篇
儿科学   74篇
妇产科学   51篇
基础医学   473篇
口腔科学   148篇
临床医学   341篇
内科学   784篇
皮肤病学   72篇
神经病学   148篇
特种医学   107篇
外科学   527篇
综合类   117篇
一般理论   2篇
预防医学   387篇
眼科学   111篇
药学   445篇
中国医学   64篇
肿瘤学   282篇
  2024年   8篇
  2023年   62篇
  2022年   212篇
  2021年   316篇
  2020年   184篇
  2019年   159篇
  2018年   190篇
  2017年   145篇
  2016年   150篇
  2015年   175篇
  2014年   203篇
  2013年   217篇
  2012年   330篇
  2011年   344篇
  2010年   165篇
  2009年   117篇
  2008年   193篇
  2007年   176篇
  2006年   172篇
  2005年   144篇
  2004年   112篇
  2003年   107篇
  2002年   90篇
  2001年   12篇
  2000年   15篇
  1999年   18篇
  1998年   5篇
  1997年   5篇
  1996年   11篇
  1995年   7篇
  1994年   8篇
  1993年   3篇
  1992年   7篇
  1991年   8篇
  1990年   11篇
  1989年   9篇
  1988年   7篇
  1987年   5篇
  1986年   5篇
  1985年   8篇
  1984年   6篇
  1981年   3篇
  1979年   8篇
  1975年   2篇
  1974年   2篇
  1973年   2篇
  1972年   2篇
  1971年   2篇
  1969年   3篇
  1967年   2篇
排序方式: 共有4168条查询结果,搜索用时 46 毫秒
71.
The diagnosis of patients with fever of unknown origin (FUO) is often problematic because the range of possible differential diagnoses is broad. We report on a case in which a patient presented with FUO and was subsequently found to have both a collagen vascular disease and an intercurrent infection. Treatment for the collagen vascular disease with corticosteroids exacerbated the intercurrent infection. The problems in the diagnosis and management of such cases are discussed.  相似文献   
72.
In this research, tannin (TA) extracted from Acacia mangium and a cationic surfactant, cetyltrimethylammonium bromide (CTAB), were used to modify and enhance the physical and electrochemical properties of a polypyrrole (PPy) composite. Brunauer–Emmett–Teller (BET) analysis presented a higher degree of surface area and porosity for the PPy/TA/CTAB nanocomposite. A highly porous and rod like structure with a lumpy surface was observed for PPy/TA prepared in the presence of CTAB by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). Cyclic voltammograms of the modified SPE electrode using PPy/TA/CTAB displayed an enhanced current response compared to the electrode modified with only PPy or PPy/TA. Electrochemical Impedance Spectroscopy (EIS) exhibited a lower value of charge transfer resistance (Rct) and higher electron transfer for the modified electrode, making the nanocomposite a promising candidate for biosensor application.

Tannin (TA) extracted from Acacia mangium and a cationic surfactant, cetyltrimethylammonium bromide (CTAB), were used to modify and enhance the physical and electrochemical properties of polypyrrole (PPy) composite.  相似文献   
73.

Objective

To evaluate the effectiveness of exercise, ergonomic modification, and a combination of training exercise and ergonomic modification on the scores of pain in office workers with neck, shoulders, and lower back pain.

Methods

Participants (N = 142) in this randomized controlled trial were office workers aged 20–50 years old with neck, shoulders, and lower back pain. They were randomly assigned to either the ergonomic modification group, the exercise group, the combined exercise and ergonomic modification group, or the control group (no-treatment). The exercise training group performed a series of stretching exercises, while the ergonomic group received some modification in the working place. Outcome measures were assessed by the Cornell Musculoskeletal Disorders Questionnaire at baseline, after 2, 4, and 6 months of intervention.

Results

There was significant differences in pain scores for neck (MD ?10.55; 95%CI ?14.36 to ?6.74), right shoulder (MD ?12.17; 95%CI ?16.87 to ?7.47), left shoulder (MD ?11.1; 95%CI ?15.1 to ?7.09) and lower back (MD ?7.8; 95%CI ?11.08 to ?4.53) between the exercise and control groups. Also, significant differences were seen in pain scores for neck (MD ?9.99; 95%CI ?13.63 to ?6.36), right shoulder (MD ?11.12; 95%CI ?15.59 to ?6.65), left shoulder (MD ?10.67; 95%CI ?14.49 to ?6.85) and lower back (MD ?6.87; 95%CI ?10 to ?3.74) between the combined exercise and ergonomic modification and control groups. The significant improvement from month 4 to 6, was only seen in exercise group (p < 0.05).

Conclusion

To have a long term effective on MSDs, physical therapists and occupational therapists should use stretching exercises in their treatment programs rather than solely rely on ergonomic modification.
74.
75.

BACKGROUND/OBJECTIVES

This study aims to determine contribution of meal frequency, self-efficacy for healthy eating, and availability of healthy foods towards diet quality of adolescents in Kuala Lumpur, Malaysia.

SUBJECTS/METHODS

This study was conducted among 373 adolescents aged from 13 to 16 years old. Diet quality of the respondents was assessed using the Healthy Eating Index for Malaysians. Meal frequency, self-efficacy for healthy eating, and availability of healthy foods were assessed through the Eating Behaviours Questionnaire (EBQ), self-efficacy for healthy eating scale, and availability of healthy foods scale, respectively.

RESULTS

The majority of the respondents (80.7%) were at risk of poor diet quality. Males (mean = 34.2 ± 8.2%) had poorer diet quality than females (mean = 39.9 ± 9.0%) (t = -5.941, P < 0.05). Malay respondents (mean = 36.9 ± 8.7%) had poorer diet quality than Indian respondents (mean = 41.3 ± 10.0%) (F = 2.762, P < 0.05). Age (r = 0.123, P < 0.05), self-efficacy for healthy eating (r = 0.129, P < 0.05), and availability of healthy foods (r = 0.159, P < 0.05) were positively correlated with the diet quality of the respondents. However, meal frequency was not correlated with the diet quality of the respondents. Multiple linear regression analysis showed that being a male, being a Malay, low self-efficacy for healthy eating, and low availability of healthy foods contributed significantly towards poor diet quality among respondents.

CONCLUSIONS

In short, sex, ethnicity, self-efficacy for healthy eating, and availability of healthy foods were associated with diet quality among adolescents. Health practitioners should take into consideration of differences in sex and ethnicity during implementation of nutrition-related intervention programs. Self-efficacy for healthy eating and availability of healthy foods should be included as important components in improving diet quality of adolescents.  相似文献   
76.
77.
78.
In this study, a composite material, manganese oxide/reduced titania nanotubes (Mn2O3/R-TNTs), was synthesized through incorporation of Mn2O3 onto R-TNTs via the reverse pulse electrodeposition technique. The influence of pulse reverse duty cycles on the morphological, structural and electrochemical performance of the surface was studied by varying the applied duty cycle from 10% to 90% for 5 min total on-time at an alternate potential of −0.90 V (Eon) and 0.00 V (Eoff). FESEM analysis revealed the uniform deposition of Mn2O3 on the circumference of the nanotubes. The amount of Mn2O3 loaded onto the R-TNTs increased as a higher duty cycle was applied. Cyclic voltammetry and galvanostatic charge–discharge tests were employed to elucidate the electrochemical properties of all the synthesized samples in 1 M KCl. The specific capacitance per unit area was greatly enhanced upon the incorporation of Mn2O3 onto R-TNTs, but showed a decrease as a high duty cycle was applied. This proved that low amounts of Mn2O3 loading enhanced the facilitation of the active ions for charge storage purposes. The optimized sample, Mn2O3/R-TNTs synthesized at 10% duty cycle, exhibited high specific capacitance of 18.32 mF cm−2 at a current density of 0.1 mA cm−2 obtained from constant current charge–discharge measurements. This revealed that the specific capacitance possessed by Mn2O3/R-TNTs synthesized at 10% duty cycle was 6 times higher than bare R-TNTs.

Mn2O3 was coated onto reduced titania nanotubes by reverse pulse electrodeposition, showing smooth and homogenous deposits without covering the opening of the nanotubes.  相似文献   
79.
Journal of Thrombosis and Thrombolysis - Tandem occlusions exist in 17–32% of large vessel occlusion (LVO) strokes. A significant concern is bleeding when carotid stenting is performed in...  相似文献   
80.
AIDS and Behavior - A robust evidence-base describes the beneficial association between opioid agonist therapy (OAT) and HIV-related outcomes among people living with HIV and opioid use disorder....  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