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   271篇
  免费   19篇
儿科学   16篇
妇产科学   8篇
基础医学   15篇
口腔科学   5篇
临床医学   30篇
内科学   81篇
皮肤病学   5篇
神经病学   21篇
特种医学   3篇
外科学   36篇
综合类   6篇
预防医学   4篇
药学   13篇
中国医学   1篇
肿瘤学   46篇
  2021年   3篇
  2020年   1篇
  2018年   1篇
  2017年   3篇
  2016年   10篇
  2015年   9篇
  2014年   5篇
  2013年   2篇
  2012年   9篇
  2011年   6篇
  2010年   6篇
  2009年   5篇
  2008年   1篇
  2007年   8篇
  2006年   15篇
  2005年   6篇
  2004年   6篇
  2003年   4篇
  2002年   7篇
  2000年   3篇
  1999年   5篇
  1998年   11篇
  1997年   13篇
  1996年   7篇
  1995年   11篇
  1994年   12篇
  1993年   8篇
  1992年   11篇
  1991年   6篇
  1990年   5篇
  1989年   2篇
  1987年   2篇
  1986年   13篇
  1985年   5篇
  1984年   5篇
  1983年   2篇
  1982年   4篇
  1981年   3篇
  1980年   2篇
  1978年   3篇
  1977年   1篇
  1975年   1篇
  1971年   2篇
  1970年   1篇
  1967年   1篇
  1958年   11篇
  1957年   11篇
  1956年   9篇
  1955年   5篇
  1954年   7篇
排序方式: 共有290条查询结果,搜索用时 15 毫秒
81.
82.
A 48-year-old man with a small cell carcinoma of the lung presentedhyponatremia and was diagnosed as having the syndrome of inappropriateADH secretion. A plasma ADH bioassay confirmed this syndrome.During the clinical course, the patient developed a hyponatremiccrisis with a serum sodium of 108mEq/l. His hyponatremia wasrapidly corrected by infusing furosemide in conjunction withhypertonic saline. The postmortem studies demonstrated ADH bioactivityin the tumor tissues, as well as immunoreactive ACTH, ß-MSHand calcitonin. Tumor hypersecretion of ACTH appeared to bethe cause of the patient's hyperresponsiveness to exogenousACTH and of the bilateral adrenocortical hyperplasia observedat the time of autopsy. Therefore, this was a case of a multiple hormone-producing smallcell carcinoma of the lung, in which the severe clinical manifestationsof SIADH were successfully treated with furosemide and hypertonicsaline.  相似文献   
83.
84.
85.
Patients with advanced breast cancer were treated with antiestrogen,tamoxifen, 20 mg orally, twice a day. Of the evaluable 23 patients,one achieved complete response with a duration of 16 months,and five achieved partial response lasting from two to eightmonths, indicating that the response rate was 26%. In the fiveperi-and postmenopausal patients, basal and LH-RH stimulatedplasma LH levels decreased but stayed within the postmenopausalrange in three patients during the tamoxifen therapy. Basaland LH-RH stimulated FSH levels decreased also but stayed withinthe postmenopausal range in all five patients. In a premenopausalpatient, basal and stimulated plasma LH and FSH levels did notchange significantly during the tamoxifen therapy. The plasmaTSH responses did not change significantly. In three of thesix patients, basal and TRH-stimulated prolactin levels decreasedslightly during the tamoxifen therapy. These relatively inconsistentand small changes in the pituitary hormone secretion observedduring the tamoxifen therapy suggest that the anti-tumor effectof tamoxifen was not due to alteration of the pituitary hormonesecretion. The binding of tamoxifen for the estrogen receptorwas examined in the estrogen receptor assay system. The doseresponse curve for tamoxifen was parallel to that for estradiol,indicating that tamoxifen competes with estradiol for the estrogenreceptor. The affinity constants of tamoxifen for the estrogenreceptor in eight cytosols of human breast cancer tissues were(139 ±79) X 10–10M (mean±SD), indicatingthat the binding affinity of tamoxifen was about 0.7% that ofestradiol. The affinity constants for nuclear receptors weresimilar to those for cytosol receptors. These data suggest thattamoxifen is a useful drug for treatment of advanced breastcancer, and that the anti-tumor effect could be related to itsbinding to estrogen receptors in tumor tissues, and not causedby altering the secretion of pituitary hormones.  相似文献   
86.
Aim: The Clinical Dementia Rating (CDR) is an assessment of dementia severity based on observations of activities of daily living, and a CDR of 0.5 (CDR 0.5) represents questionable dementia. A combination of the Cognitive Abilities Screening Instrument (CASI) and the Trail Making Test (TMT) scores discriminated CDR 0.5 subjects from healthy participants with a high degree of accuracy. We investigated the neurological background of CDR 0.5 subjects by correlating CASI and TMT scores with regional cerebral blood flow (rCBF) as measured by single photon emission computed tomography (SPECT). Methods: From a community‐based cohort, 22 CDR 0.5 participants were recruited. CASI and TMT scores, rCBF measure using [123I]‐N‐isopropyl‐p‐iodoamphetamine and SPECT were obtained. We evaluated the relationships between the CASI domain scores, between TMT scores and rCBF in a regions‐of‐interest‐based analysis, and voxel‐based analysis using Statistical Parametric Mapping 5 software. Results: We found that lower rCBF in the left medial temporal cortex correlated with a decreased CASI domain recent memory score both in the regions‐of‐interest and statistical parametric mapping analysis. In both the regions‐of‐interest and statistical parametric mapping analysis, the rCBF in the left prefrontal cortex correlated with CASI domain remote memory and mental manipulation and concentration. Conclusions: Our results indicate that some CDR 0.5 subjects have functional impairments in the medial temporal lobe as well as in the prefrontal cortex, as reflected in the cognitive decline measured by CASI and TMT.  相似文献   
87.
88.
Background: In out‐patient clinics, having simple procedures to check for signs of dementia is invaluable. In the present study, we evaluated the imitation of hand gestures to detect visuomotor deficits in dementia in clinical practice. Methods: In all, 1219 subjects were enrolled in the present study, including 497 with Alzheimer's disease (AD), 98 with dementia with Lewy bodies (DLB), 71 with other types of dementia diseases, 175 with a Clinical Dementia Rating (CDR) of 0.5, and 378 normal controls. All subjects were aged 65 years or older. Subjects were recruited from 10 clinics and two communities. Visuomotor function was evaluated by the Yamaguchi fox–pigeon imitation test (YFPIT), which consists of a simple one‐handed sign for ‘fox’ and a complex two‐handed sign for ‘pigeon’, a rapid, game‐like test with low psychological burden. Results: The success rate (successful/total) for imitating the ‘pigeon’ hand gesture was reduced as the severity of the dementia increased: 85.7% in normal controls, 60.6% in CDR 0.5 (mild cognitive impairment), 39.2% in CDR 1 (mild dementia), 21.2% in CDR 2 (moderate dementia), and 5.7% in CDR 3 (severe dementia). The success rate for imitating the ‘pigeon’ hand gesture was higher in patients with DLB than AD within the CDR 1 group (51.2% vs 35.4%, respectively), but lower for patients with DLB than AD within the CDR 2 group (12.5% vs 24.4%, respectively). The success of imitating the hand gesture for ‘fox’ was similar for patients with AD and DLB. Of those subjects who failed to imitate the hand gesture for ‘pigeon’, 49.5% of those with AD showed the palm–palm pattern (both palms facing outward), suggesting deficits of perspective conversion from the first‐person to the third‐person. Conversely, 52.8% of patients with DLB showed a dorsum–dorsum pattern (both dorsa facing outwards), suggesting deterioration of visual attention and recognition. Conclusion: In conclusion, the YFPIT is a useful test to detect visuomotor deficits in dementia that can differentiate between AD and DLB.  相似文献   
89.
We investigated the cardiovascular responses to active standingin Swedish and Japanese pre-pubertal children using non-invasivecontinuous beat-to-beat finger blood pressure (BP) monitoring.Seventy-eight Swedish (7–12 years) and 53 Japanese children(6–12 years) were examined. There were no significantdifferences in body weight or height between the two groups(total group). Finger blood pressure and heart rate were continuouslyrecorded in the supine position and during standing. SupineBP was significantly higher in Swedish compared to Japanesechildren (115/65 vs 98/50mmHg, P<0.001), and Swedish childrenshowed a significantly larger initial BP drop upon rising (–28/15 vs –141 –10 mmHg, P<0.05) and alarger increment of heart rate (39 ± 10 vs 29 ±8 beats. min–1, P<0.05). There were, however, no differencesin the blood pressure and heart rate changes in the followingsteady state period (2–3 min) between the two groups. These results suggest that Swedish pre-pubertal children havea higher basal blood pressure and enhanced cardiovascular autonomicresponses, such as pronounced baroreflex receptor sensitivityand vasoconstrictor mechanisms. These differences in the twocohorts were not related to body dimensions or degree of maturation,indicating that autonomic functions in the cardiovascular systemlargely depend on genetic factors and environmental variables.  相似文献   
90.
In Orthodontics, fixed appliances placed in the oral cavity are colonized by microorganisms.

Objective

The purpose of this study was to quantitatively determine the independent bacterial colonization of S. mutans and S. sobrinus in orthodontic composite resins.

Material and methods

Seven orthodontic composite adhesives for bonding brackets were selected and classified into 14 groups; (GIm, GIs) Enlight, (GIIm, GIIs) Grengloo, (GIIIm, GIIIs) Kurasper F, (GIVm, GIVs) BeautyOrtho Bond, (GVm, GVs) Transbond CC, (GVIm, GVIs) Turbo Bond II, (GVIIm, GVIIs) Blugloo. 60 blocks of 4x4x1 mm of each orthodontic composite resin were made (total 420 blocks), and gently polished with sand-paper and ultrasonically cleaned. S. mutans and S. sobrinus were independently cultivated. For the quantitative analysis, a radioactive marker was used to codify the bacteria (3H) adhered to the surface of the materials. The blocks were submerged in a solution with microorganisms previously radiolabeled and separated (210 blocks for S. mutans and 210 blocks for S. sobrinus) for 2 hours at 37ºC. Next, the blocks were placed in a combustion system, to capture the residues and measure the radiation. The statistical analysis was calculated with the ANOVA test (Sheffè post-hoc).

Results

Significant differences of bacterial adhesion were found amongst the groups. In the GIm and GIs the significant lowest scores for both microorganisms were shown; in contrast, the values of GVII for both bacteria were significantly the highest.

Conclusions

This study showed that the orthodontic composite resin evaluated in the GIm and GIs, obtained the lowest adherence of S. mutans and S. sobrinus, which may reduce the enamel demineralization and the risk of white spot lesion formation.  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