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   367篇
  免费   17篇
  国内免费   36篇
儿科学   13篇
妇产科学   5篇
基础医学   82篇
口腔科学   4篇
临床医学   49篇
内科学   72篇
皮肤病学   2篇
神经病学   29篇
特种医学   36篇
外科学   47篇
综合类   12篇
预防医学   16篇
眼科学   3篇
药学   34篇
中国医学   1篇
肿瘤学   15篇
  2023年   4篇
  2021年   7篇
  2020年   7篇
  2018年   4篇
  2017年   6篇
  2016年   7篇
  2015年   12篇
  2014年   13篇
  2013年   15篇
  2012年   12篇
  2011年   19篇
  2010年   11篇
  2009年   11篇
  2008年   15篇
  2007年   30篇
  2006年   13篇
  2005年   15篇
  2004年   10篇
  2003年   8篇
  2002年   8篇
  2001年   9篇
  2000年   5篇
  1998年   9篇
  1997年   16篇
  1996年   10篇
  1995年   12篇
  1994年   8篇
  1993年   6篇
  1992年   8篇
  1991年   7篇
  1990年   10篇
  1989年   6篇
  1988年   13篇
  1987年   5篇
  1986年   5篇
  1985年   8篇
  1984年   3篇
  1983年   5篇
  1982年   6篇
  1980年   2篇
  1979年   6篇
  1977年   4篇
  1975年   6篇
  1973年   5篇
  1972年   2篇
  1971年   5篇
  1970年   3篇
  1969年   1篇
  1968年   1篇
  1965年   1篇
排序方式: 共有420条查询结果,搜索用时 15 毫秒
81.
AIM: The purposes of this study were to determine the age-related changes in the tendon-aponeurosis structures and to investigate the effects of low-load resistance training on the tendon-aponeurosis structures in middle-aged and elderly women. METHODS: Fifty-one women (55.8 +/- 13.7 years, range: 21-77 years) volunteered to take part in the present study. Furthermore, 11 middle-aged and elderly women (49.7 +/- 9.2 years) performed the low-load resistance training, i.e. squat using body weight, for 6 months. The elongation of the tendon and aponeurosis of the vastus lateralis muscle was directly measured by ultrasonography, while the subjects performed ramp isometric knee extension up to the voluntary maximum, followed by a ramp relaxation. The relationship between the estimated muscle force (Fm) and tendon elongation (L) during the ascending phase was fitted to a linear regression, the slope of which was defined as stiffness. The percentage of the area within the Fm-L loop to the area beneath the curve during the ascending phase was calculated as hysteresis. RESULTS: Maximal strain (L/initial tendon length) and stiffness of the tendon-aponeurosis structures decreased significantly with ageing. In contrast, the hysteresis increased significantly with ageing. In addition, low-load resistance training produced no significant change in stiffness and hysteresis, but significantly increased the maximal elongation of tendon-aponeurosis structures from 23.3 +/- 2.1 mm to 24.8 +/- 2.2 mm (P = 0.045). CONCLUSION: These results suggest that increasing age results in a decrease in the elasticity of tendon-aponeurosis structures and an increase in their viscosity. Furthermore, the low-load resistance training made the elasticity of tendon-aponeurosis structures increase.  相似文献   
82.
83.
We determined the occurrence and association of cortical cerebral microinfarcts (CMIs) at 7 T MRI with risk factors, neuroimaging markers of small and large vessel disease, and cognitive functioning. Within the Medea-7T study, a diverse cohort of older persons with normal cognition, patients with vascular disease, and memory clinic patients, we included 386 participants (68 ± 9 years) with available 7 T and 1.5 T/3T brain MRI, and risk factor and neuropsychological data. CMIs were found in 10% of participants and were associated with older age (RR = 1.79 per +10 years, 95%CI 1.28–2.50), history of stroke or TIA (RR = 4.03, 95%CI 2.18–7.43), cortical infarcts (RR = 5.28, 95%CI 2.91–9.55), lacunes (RR = 5.66, 95%CI 2.85–11.27), cerebellar infarcts (RR = 2.73, 95%CI 1.27–5.84) and decreased cerebral blood flow (RR = 1.35 per −100 ml/min, 95%CI 1.00–1.83), after adjustment for age and sex. Furthermore, participants with >2 CMIs had 0.5 SD (95%CI 0.05–0.91) lower global cognitive performance, compared to participants without CMIs. Our results indicate that CMIs on 7 T MRI are observed in vascular and memory clinic patients with similar frequency, and are associated with older age, history of stroke or TIA, other brain infarcts, and poorer global cognitive functioning.  相似文献   
84.
85.
86.
AIM:To assess the value of a new test for the diagnosis of Helicobacter pylori(H.pylori) infection,Rapirun H.pylori Antibody Stick(Rapirun Stick),in a Vietnamese population.METHODS:Eligible patients without previous history of H.pylori eradication were recruited.Rapid urease test(RUT) and histologic examination were used to diagnose the H.pylori infection.Patients were considered H.pylori positive when the RUT results were positive and/or the bacteria were detected histologically.Rapirun Stick tests were performed using urine samples,and the results were compared with the other 2 methods.RESULTS:We enrolled 200 patients with a mean age of 36(range,18-76) years.There were 116 females and 84 males.Of the 200 patients,111(55.5%) were diagnosed as being H.pylori positive.The sensitivity,specificity,and accuracy of the Stick test were 84.7%,89.9%,and 87.0%,respectively.There were 17(8.5%) falsenegative patients and 9(4.5%) false-positive patients.CONCLUSION:The Rapirun Stick test has high sensitivity,specificity,and accuracy for the diagnosis of H.pylori infection in the Vietnamese population.The test can be clinically applied in Vietnamese populations.  相似文献   
87.
AIM: To evaluate the risk factors for postoperative bleeding after gastric endoscopic submucosal dissection(ESD) based on the latest guidelines.METHODS: A total of 262 gastric neoplasms were treated by ESD at our center during a 2-year period from October 2012. We analyzed the data of these cases retrospectively to identify the risk factors for postESD bleeding.RESULTS: Of the 48(18.3%) cases on antithrombotic treatment, 10 were still receiving antiplatelet drugs perioperatively, 13 were on heparin replacement after oral anticoagulant withdrawal, and the antithrombotic therapy was discontinued perioperatively in 25 cases. Postoperative bleeding occurred in 23 cases(8.8%). The postoperative bleeding rate in the heparin replacement group was 61.5%, significantly higher than that in the non-antithrombotic therapy group(6.1%). Univariate analysis identified history of antithrombotic drug use, heparin replacement, hemodialysis, cardiovascular disease, diabetes mellitus, elevated prothrombin timeinternational normalized ratio, and low hemoglobin level on admission as risk factors for post ESD bleeding. Multivariate analysis identified only heparin replacement(OR = 13.7, 95%CI: 1.2-151.3, P = 0.0329) as a significant risk factor for post-ESD bleeding.CONCLUSION: Continued administration of antiplatelet agents, based on the guidelines, was not a risk factor for postoperative bleeding after gastric ESD; however, heparin replacement, which is recommended after withdrawal of oral anticoagulants, was identified as a significant risk factor.  相似文献   
88.
89.
Widespread radiopacity of jaw bones in familial adenomatosis coli   总被引:1,自引:0,他引:1  
Abnormalities of jaw bones and teeth were evaluated in 37 patients with familial adenomatosis coli (FAC) by means of orthopantomography. Osteomatous radiopaque lesions were evident in 75.7 percent of FAC patients (focal type: 62.2% and wide spread type: 13.5%), odontomes in 29.7% peripheral osteomas in 13.5%, unerupted teeth in 16.2% and supernumerary unerupted teeth in 16.2%. Five of the 37 FAC patients had an unusual widespread type of radiopacity with other abnormalities. Combined abnormalities were most frequent in patients with this type in comparison with patients with the focal type. Osteomas and peripheral osteomas were revealed in this type with statistical significance. Biopsy performed in one patient revealed an osteoma. These results suggest that the multiple abnormalities seen in oral X-ray examination may predict the occult existence of familial adenomatosis coli and these widespread radiopaque lesions probably represent the most extensive manifestation of FAC.  相似文献   
90.
OBJECTIVE: The purpose of the present study was to clarify the association of serum cytokine concentrations, determined using a multiplexed cytokine assay, with psychological symptoms in midlife women. METHODS: Fifty-three peri- and post-menopausal women with and without psychological symptoms in Greene's climacteric scale were enrolled in this study. Levels of 17 cytokines in serum samples were measured simultaneously using a multiplexed human cytokine assay. RESULTS: Serum interleukin (IL)-6 concentration in women with psychological symptoms (2.71+/-047 pg/ml) was significantly (p=0.009) higher than that in women without psychological symptoms (0.98+/-0.18 pg/ml). Serum IL-8 concentration in women with psychological symptoms (33.4+/-8.17 pg/ml) was also significantly (p=0.022) higher than that in women without psychological symptoms (7.87+/-1.64 pg/ml). In addition, serum IL-10 concentration in women with psychological symptoms (0.74+/-0.26 pg/ml) was significantly (p=0.048) higher than that in women without psychological symptoms (0.07+/-0.04 pg/ml). Tumor necrosis factor (TNF)-alpha in serum was detected only in women with psychological symptoms. Serum IL-2 concentration in women with psychological symptoms tended (p=0.066) to be higher than that in women without psychological symptoms. No significant differences were found between levels of other cytokines in women with and without psychological symptoms. CONCLUSION: Psychological stress manifested as climacteric symptoms in midlife women may be associated with increases in serum concentrations of IL-6, IL-8, IL-10, and TNF-alpha.  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