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   1147篇
  免费   57篇
  国内免费   7篇
耳鼻咽喉   18篇
儿科学   62篇
妇产科学   36篇
基础医学   82篇
口腔科学   72篇
临床医学   85篇
内科学   225篇
皮肤病学   48篇
神经病学   99篇
特种医学   59篇
外科学   211篇
综合类   19篇
预防医学   15篇
眼科学   47篇
药学   37篇
中国医学   40篇
肿瘤学   56篇
  2024年   7篇
  2023年   9篇
  2022年   16篇
  2021年   16篇
  2020年   21篇
  2019年   16篇
  2018年   22篇
  2017年   31篇
  2016年   26篇
  2015年   39篇
  2014年   49篇
  2013年   75篇
  2012年   82篇
  2011年   104篇
  2010年   54篇
  2009年   50篇
  2008年   80篇
  2007年   97篇
  2006年   96篇
  2005年   87篇
  2004年   64篇
  2003年   44篇
  2002年   32篇
  2001年   6篇
  2000年   17篇
  1999年   9篇
  1998年   8篇
  1997年   12篇
  1996年   3篇
  1995年   3篇
  1994年   6篇
  1993年   1篇
  1992年   4篇
  1991年   2篇
  1990年   4篇
  1989年   1篇
  1988年   1篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1980年   4篇
  1979年   1篇
  1969年   1篇
  1967年   1篇
  1965年   1篇
  1935年   1篇
排序方式: 共有1211条查询结果,搜索用时 15 毫秒
991.
992.
Yaren A  Kelten C  Akbulut M  Teke Z  Duzcan E  Erdem E 《Tumori》2007,93(5):496-498
Primary neuroendocrine carcinoma of the breast is an extremely rare tumor. We present our experience of primary neuroendocrine carcinoma of the breast in a 76-year-old woman. Surgical biopsies from breast and axillary lymphadenopathy showed a neuroendocrine carcinoma. Immunohistochemical staining of tumor cells with GCDFP15, NSE and chromogranin were positive. Computed tomography scans of the chest and abdomen showed no lesion for metastasis or another primary origin. Adjuvant hormone therapy was given, since the tumor was immunohistochemically receptor positive.  相似文献   
993.
Pemetrexed was approved for the treatment of relapsed or chemotherapy refractory non-small cell lung cancer patients, as it produced similar response and survival outcomes and less toxicity as compared to taxotere. Pemetrexed in combination with platinum analogs or with gemcitabine or vinorelbine, produce equivalent responses and overall survival results compared to combinations of platinum analogs with other drugs. The role of bevacizumab and the inhibitors of epithelial growth factor receptor also should be evaluated in selected patients with NSCLC treated with pemetrexed combinations. Further increases in drug dose may be possible using transfer of drug resistance genes in hematopoietic stem cells.  相似文献   
994.
Background: Diabetes mellitus affects the systolic and diastolic function of the left ventricle (LV). The aim of the present study was to evaluate the index of myocardial performance (IMP), a new Doppler index, in asymptomatic, normotensive patients with type 2 diabetes mellitus (T2DM). Methods: The study population consisted of 40 asymptomatic normotensive patients with T2DM (22 women, 18 men; mean [±SD] age 49 ± 7 years) and 20 healthy controls (13 women, seven men; mean age 45 ± 4 years). M‐Mode and two‐dimensional Doppler echocardiography was performed in all subjects to calculate IMP. Venous blood samples were collected for analysis and body mass index (BMI) was calculated. Results: In normotensive T2DM patients, the mitral E wave was decreased, whereas mitral A wave, mitral E/A ratio, and septal wall thickening were increased compared with values obtained for the control group. The IMP was higher in normotensive T2DM patients than in the control group (P = 0.004). There was a significant correlation between IMP and triglyceride (TG) levels (P < 0.001), mitral E wave (P < 0.001), mitral E/A ratio (P < 0.001), ejection fraction (P = 0.001), fasting blood glucose (P =0.007), LV systolic dimension (P < 0.001), duration of diabetes (P = 0.017), and BMI (P = 0.029). Stepwise multiple regression analysis demonstrated that only TG levels (β = 0.355, t = 2.487, P = 0.017) and the mitral E/A ratio (β = ?0.384, t = ?2.690, P = 0.011) had an independent effect on IMP. Conclusion: The results of the present study indicate that IMP is increased in normotensive T2DM patients. The findings suggest that increased IMP may be an early sign of diabetic cardiomyopathy in normotensive diabetic patients with preserved LV function.  相似文献   
995.

BACKGROUND:

Large artery stiffness is a major determinant of pulse pressure (PP), and PP at baseline has been associated with future coronary events.

OBJECTIVE:

To evaluate the impact of the metabolic syndrome on aortic PP and ascending aortic pulsatility (AP) in patients with angiographically normal coronary arteries.

METHODS:

Forty-two patients with the metabolic syndrome and 40 age-matched control subjects without the metabolic syndrome were included in the study. All subjects had normal coronary arteries. Diagnosis of the metabolic syndrome was based on the International Diabetes Federation guidelines published in 2005. Ascending AP was estimated as the ratio of aortic PP to mean blood pressure.

RESULTS:

Aortic PP (59±12 mmHg versus 43±10 mmHg; P<0.001) and ascending AP (0.54±0.10 versus 0.48±0.10; P<0.001) were significantly higher in the metabolic syndrome group. Multiple regression analysis revealed statistically independent relationships between ascending AP and fasting blood glucose, waist circumference and systolic blood pressure (model R2=0.408; P<0.001). The metabolic syndrome, as a whole, was also independently associated with both ascending AP (P<0.01) and aortic PP (P<0.01).

CONCLUSION:

The data showed that the metabolic syndrome is independently associated with increased aortic PP and ascending AP in patients with normal coronary arteries, suggesting aortic stiffness as one of the possible mechanisms underlying the excess cardiovascular risk associated with the metabolic syndrome.  相似文献   
996.
OBJECTIVE: To assess the ability for visual search and recognition of roadside targets and safety errors during a landmark and traffic sign identification task in drivers with Parkinson's disease (PD). METHODS: Seventy-nine drivers with PD and 151 neurologically normal older adults underwent a battery of visual, cognitive, and motor tests. The drivers were asked to report sightings of specific landmarks and traffic signs along a four-lane commercial strip during an experimental drive in an instrumented vehicle. RESULTS: The drivers with PD identified significantly fewer landmarks and traffic signs, and they committed more at-fault safety errors during the task than control subjects, even after adjusting for baseline errors. Within the PD group, the most important predictors of landmark and traffic sign identification rate were performances on Useful Field of View (visual speed of processing and attention) and Complex Figure Test-Copy (visuospatial abilities). Trail Making Test (B-A), a measure of cognitive flexibility independent of motor function, was the only independent predictor of at-fault safety errors in drivers with PD. INTERPRETATION: The cognitive and visual deficits associated with PD resulted in impaired visual search while driving, and the increased cognitive load during this task worsened their driving safety.  相似文献   
997.
998.
999.
1000.
Objectives:To compare the effects of different etching techniques, 12–, 24–bladed tungsten carbide burs, and polishing discs on tooth color changes during orthodontic treatment.Materials and Methods:59 individuals (mean age: 15.20 ± 1.59 years) were divided into four groups: 37% phosphoric acid and adhesive primer was used in Groups I and II whereas self–etch primer was used in Groups III and IV for enamel preparation. After orthodontic treatment, residual adhesives were cleaned with 12–bladed tungsten carbide burs in Groups I and III, while 24–bladed tungsten carbide burs were used in Groups II and IV. All teeth were polished with medium and fine Sof–Lex XT discs (3M ESPE, St Paul, Minnesota). Color measurements were taken from upper incisors and canines at pretreatment (T0), after cleaning with tungsten carbide burs (T1) and polishing with discs (T2). Wilcoxon test was used for evaluation of L*, a*, b* changes and Kruskal–Wallis for intergroup comparison of color changes.Results:L*, a*, b* values, except a* at Groups I, II, IV, and b* at Group III, changed significantly (P < .05). Groups III and IV showed significantly different color alterations from T0 to T1 (P < .05). After polishing, tooth color alterations were not significantly different among the groups.Conclusions:In self–etch bonding groups, a 12–bladed tungsten carbide bur caused less color change than the 24–bladed tungsten carbide bur. Orthodontic treatment resulted with visible and clinically unacceptable tooth color alterations regardless of the enamel preparation and clean–up techniques. Polishing reduced the effect of tungsten carbide burs, but did not affect the total influence of orthodontic treatment on the tooth color.  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