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   7125篇
  免费   438篇
  国内免费   98篇
耳鼻咽喉   89篇
儿科学   114篇
妇产科学   140篇
基础医学   730篇
口腔科学   272篇
临床医学   596篇
内科学   2217篇
皮肤病学   113篇
神经病学   617篇
特种医学   250篇
外科学   1201篇
综合类   16篇
一般理论   1篇
预防医学   294篇
眼科学   72篇
药学   334篇
中国医学   6篇
肿瘤学   599篇
  2024年   15篇
  2023年   136篇
  2022年   260篇
  2021年   472篇
  2020年   275篇
  2019年   313篇
  2018年   351篇
  2017年   242篇
  2016年   287篇
  2015年   298篇
  2014年   387篇
  2013年   437篇
  2012年   617篇
  2011年   546篇
  2010年   303篇
  2009年   298篇
  2008年   403篇
  2007年   366篇
  2006年   343篇
  2005年   276篇
  2004年   217篇
  2003年   187篇
  2002年   144篇
  2001年   50篇
  2000年   39篇
  1999年   35篇
  1998年   29篇
  1997年   15篇
  1996年   19篇
  1995年   16篇
  1994年   18篇
  1993年   8篇
  1992年   18篇
  1991年   14篇
  1990年   20篇
  1989年   22篇
  1988年   17篇
  1987年   20篇
  1986年   12篇
  1985年   16篇
  1984年   8篇
  1979年   9篇
  1978年   9篇
  1977年   10篇
  1974年   13篇
  1973年   6篇
  1972年   9篇
  1971年   8篇
  1970年   8篇
  1969年   7篇
排序方式: 共有7661条查询结果,搜索用时 343 毫秒
101.
102.
The current study demonstrated that chronic peer victimization, as compared to time-limited victimization, is particularly associated with peer status and peer-reported adjustment at the adolescent transition. Using a cohort sequential design, a sample of 653 adolescents (48% female, 87% Caucasian) in Grades 6–8 were assessed at 3 annual time points; data captured indices of peer victimization, likeability, popularity, and several peer-reported indices of internalizing (e.g., sadness, worry) and externalizing (e.g., anger, fighting) symptoms across Grades 6–10. Four trajectories of victimization experiences were identified—chronic, high decreasing, low increasing, and low stable—suggesting instability in victimization experiences over time. Adolescents who experienced chronic victimization, as compared to those with low-stable, decreasing, or increasing levels of victimization, were rated by peers more often on indices of maladjustment and less often on measures of popularity and likeability. Findings highlight negative associations with chronic victimization and underscore the need for targeted interventions to prevent chronic victimization. Overall, findings further emphasize the role of chronicity in victimization and highlight the importance of identifying chronic victims for intervention and prevention efforts.  相似文献   
103.
104.
Tissue temperature distribution plays a crucial role in the outcome of laser-induced thermotherapy (LITT), a technique employed for neoplasias removal. Since recent studies proposed LITT for pancreatic tumors treatment, assessment of temperature and of its effects around the laser applicator could be useful to define optimal laser settings. The aims of this work are temperature monitoring and measurement of ablated tissue volume in an ex vivo porcine pancreas undergoing double-applicator LITT. A three-dimensional numerical model is implemented to predict temperature rise and volumes of ablated tissue in treated pancreas. Experiments are performed to validate the model, with two modalities: (1) 12-fiber Bragg grating sensors are adopted to monitor the heating and cooling during LITT at several distances from the applicators tip, and (2) 1.5-T MR imaging is used to estimate the ablated volume. Experimental data agree with theoretical ones: at 2 mm from both applicators tips, the maximum temperature increase is approximately 60 °C downward from the tips, while it increases of about 40 °C and 30 °C, respectively, at the level and upward from the tips. This behavior occurs also at other distances, proving that the tissue downward from the tip is mostly heated. Furthermore, the estimated volume with MRI agrees with theoretical one (i.d., 0.91?±?0.09 vs. 0.95 cm3). The encouraging results indicate that the model could be a suitable tool to choose the optimal laser settings, in order to control the volume of ablated tissue.  相似文献   
105.
106.
In the past years, assessment of cardiac function has become possible through the analysis of intracardiac flow dynamics, performed noninvasively using phase‐contrast cardiac magnetic resonance and contrast and noncontrast ultrasound techniques. From 2013 to 2019, 9 echocardiographic investigations have considered 215 patients with cardiac resynchronization therapy (CRT) as a model for assessing flow dynamics within the left ventricle. Preliminary results have been reported about the acute hemodynamic effects of CRT and programming of the CRT device, showing the potential of an approach based on analysis of intracardiac flows. At present, there are only scarce data on the capability of intracardiac flow dynamics to predict LV remodeling after CRT and no information on clinical outcome prediction. Future investigations should be aimed at clarifying the mechanisms and impact of maladaptive intracardiac vortex dynamics on progressive LV remodeling as well as the prognostic meaning of implanted CRT device based on cardiac flow analysis.  相似文献   
107.
It is currently controversial if and in which terms Parkinson’s disease (PD) and restless legs syndrome (RLS) are linked in co-morbid association. In a cohort of 106 de novo PD patients (67 male and 39 female, aged 42–83 years), 15 of them developed RLS, which was prospectively assessed at 6-month intervals from the starting of dopamine(DA)ergic therapy. The incidence rate of total RLS was 47 per 1,000 case/person per year and 37 per 1,000 case/person per year after the exclusion of possible “secondary” forms of the disorder (n = 3). These figures are higher than those reported in an incidence study conducted in German general population (Study of Health in Pomerania), in which the method of ascertainment of RLS similar to ours has been used. An incidence rate of total RLS significantly higher than that reported in the above-mentioned study was found in the age ranges 55–64 years and in the age range 45–74 years standardized to European general population 2013  (70 and 53 per 1,000 case/person per year, respectively, p < 0.01). Ten out of 12 patients (83.3 %) developed RLS within 24 months from the starting of DAergic medication (median latency 7.5 months). These findings support the view that sustained DAergic therapy could represent the critical factor inducing an increased incidence of RLS in patients with PD and that the latter disease should be regarded as the condition predisposing to the occurrence of the former and not viceversa as previously hypothesized. The mechanism underlying the increased incidence of RLS remains unclear and deserves further investigation.  相似文献   
108.
109.
Low-level laser therapy (LLLT) is widely used in regenerative medicine and in dental therapy by virtue of its beneficial effects in a plethora of pathological conditions. In this study, the effect of a 980 nm diode laser on pre-osteoblasts proliferation has been evaluated, along with reactive oxygen species (ROS) production. We hypothesized that ROS were a key factor in LLLT-induced pre-osteoblasts proliferation, as it is known that ROS can induce the activation of many biological pathways, leading to cell proliferation, differentiation or apoptosis. Murine pre-osteoblasts MC3T3 cells were irradiated with different energy outputs (1–50 J) in the absence or presence of the antioxidant N-Acetyl-L-cysteine (NAC). Laser treatment, in the absence of NAC, was able to induce a fluence-dependent statistically significant increase in ROS generation, while the presence of NAC strongly inhibited it. Cell proliferation, measured after laser stimulation, was significantly increased both at low and higher energy, with a peak at 10 J in the absence of the antioxidant. On the contrary, in the presence of NAC, laser irradiation was not able to induce any cell proliferation, suggesting a crucial role of ROS in this laser-induced cell effect. These results suggest that LLLT may be a useful tool for bone regeneration therapy and an effective range of fluences to be used is indicated.  相似文献   
110.
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