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   1587篇
  免费   87篇
  国内免费   7篇
耳鼻咽喉   14篇
儿科学   49篇
妇产科学   25篇
基础医学   209篇
口腔科学   30篇
临床医学   172篇
内科学   331篇
皮肤病学   54篇
神经病学   95篇
特种医学   42篇
外科学   259篇
综合类   36篇
预防医学   104篇
眼科学   74篇
药学   119篇
中国医学   12篇
肿瘤学   56篇
  2024年   4篇
  2023年   29篇
  2022年   47篇
  2021年   74篇
  2020年   63篇
  2019年   69篇
  2018年   95篇
  2017年   57篇
  2016年   68篇
  2015年   57篇
  2014年   88篇
  2013年   101篇
  2012年   148篇
  2011年   154篇
  2010年   82篇
  2009年   66篇
  2008年   73篇
  2007年   66篇
  2006年   50篇
  2005年   55篇
  2004年   41篇
  2003年   48篇
  2002年   29篇
  2001年   15篇
  2000年   21篇
  1999年   9篇
  1998年   2篇
  1997年   3篇
  1995年   2篇
  1994年   1篇
  1993年   2篇
  1992年   5篇
  1991年   9篇
  1990年   4篇
  1989年   4篇
  1988年   4篇
  1987年   4篇
  1986年   4篇
  1985年   7篇
  1984年   4篇
  1983年   1篇
  1982年   4篇
  1981年   1篇
  1980年   1篇
  1978年   1篇
  1974年   2篇
  1972年   2篇
  1970年   2篇
  1969年   1篇
  1968年   2篇
排序方式: 共有1681条查询结果,搜索用时 15 毫秒
31.
32.
The functional relevance of brain-derived neurotrophic factor (BDNF) is beginning to be well appreciated not only in mice, but also in humans. Because reduced levels typically correlate with impaired neuronal function, increasing BDNF levels with well-tolerated drugs diffusing into the central nervous system may help in ameliorating functional deficits. With this objective in mind, we used the sphingosine-1 phosphate receptor agonist fingolimod, a drug that crosses the blood-brain barrier. In addition, fingolimod has recently been introduced as the first oral treatment for multiple sclerosis. In cultured neurons, fingolimod increases BDNF levels and counteracts NMDA-induced neuronal death in a BDNF-dependent manner. Ongoing synaptic activity and MAPK signaling is required for fingolimod-induced BDNF increase, a pathway that can also be activated in vivo by systemic fingolimod administration. Mice lacking Mecp2, a gene frequently mutated in Rett syndrome, show decreased levels of BDNF, and fingolimod administration was found to partially rescue these levels as well as the size of the striatum, a volumetric sensor of BDNF signaling in rodents. These changes correlate with increased locomotor activity of the Mecp2-deficient animals, suggesting that fingolimod may improve the functional output of the nervous system, in addition to its well-documented effects on lymphocyte egress from lymph nodes.  相似文献   
33.
Manifestations of viral infections like human immune deficiency virus (HIV) differ between women and men. There are some reports due to a higher risk of thrombosis due to antiphospholipid syndrome in HIV-infected women compared with men. The purpose of this study was demonstrating the impact of gender on serum concentration of antiphospholipid and anticardiolipin antibodies in HIV-infected patients. A total of 58 HIV-infected patients and 58 age, sex-matched healthy adults were enrolled. We measured platelets count, hemoglobin, partial thromboplastin time (PTT); prothrombin time (PT), international normalized ratio (INR), antiphospholipid IgG/IgM and anticardiolipin IgG/IgM serotypes in our studied population. Age, male-to-female ratio, hemoglobin level, PT, INR, antiphospholipid IgM isotype, anticardiolipin IgM and IgG isotypes levels were not significantly different between HIV-infected patients and healthy individuals, when CD4+ T-cell count, CD8+ T-cell count, platelet count, and PTT were significantly lower, and antiphospholipid IgG isotype levels was significantly higher in HIV patients. Antiphospholipid IgG isotypes (3.2 [2.8–4.2] vs. 2.5 [2.3–3.1]; P?<?0.001) and anticardiolipin IgG isotypes (2.2 [1.9–2.7] vs. 1.4 [1.4–1.9]; P?<?0.001) were significantly higher in HIV-infected women than in HIV-infected men. Antiphospholipid IgG/IgM and anticardiolipin IgG/IgM were significantly correlated in HIV-infected men and women when they did not had any correlation in controls. We suggest that HIV infection accelerate thrombosis in women more profoundly than in men, as a result of differences in disease progression and response to therapy in these patients.  相似文献   
34.
The aim of this study was to assess peri-operative complications, safety and efficacy of non-cemented femoral fixation in total hip arthroplasty (THA) as compared to cemented femoral fixation in the elderly population. Fifty-two matched pair analysis of patients with 75 years of age and older (104 patients), who underwent primary THA from June 1997 to December 2004, was performed based on age, sex, BMI, and Charnley classification. Mean age was 81 years (75–101) and the average follow up was 3.1 ± 2.9 years (1.2–6.4). There was no difference in peri-operative cardiopulmonary complications, pulmonary failures, deep venous thrombosis, pulmonary embolus, length of stay, or discharge deposition between the two groups. Non-cemented fixation is safe and effective in patients older than 75 years of age.  相似文献   
35.
36.
With advancing technology, the sensitivity of computed tomography (CT) for the detection of traumatic subarachnoid hemorrhage (tSAH) continues to improve. Increased resolution has allowed for the detection of hemorrhage that is limited to one or two images of the CT exam. At our institution, all patients with a SAH require intensive care unit (ICU) admission, regardless of size. It was our hypothesis that patients with small subarachnoid hemorrhage experience favorable outcomes, and may not require the intensive monitoring offered in the ICU. This retrospective study evaluated 62 patients between 2011 and 2014 who presented to our Level I trauma center emergency room for acute traumatic injuries, and found to have subarachnoid hemorrhages on CT examination. The grade of subarachnoid hemorrhage was determined using previously utilized scoring systems, such as the Fisher, Modified Fisher, and Claassen grading systems. Electronic medical records were used to evaluate for medical decline, neurological decline, neurosurgical intervention, and overall hospital course. Admitting co-morbidities were noted, as were the presence of patient intoxication and use of anticoagulants. Patient outcomes were based on discharge summaries upon which the neurological status of the patient was assessed. Each patient was given a score based on the Glasgow outcome scale. The clinical and imaging profile of 62 patients with traumatic SAH were studied. Of the 62 patients, 0 % underwent neurosurgical intervention, 6.5 % had calvarial fractures, 25.8 % had additional intracranial hemorrhages, 27.4 % of the patients had significant co-morbidities, and 1.6 % of the patients expired. Patients with low-grade tSAH spent less time in the ICU, demonstrated neurological and medical stability during hospitalization. None of the patients with low-grade SAH experienced seizure during their admission. In our study, patients with low-grade tSAH demonstrated favorable clinical outcomes. This suggests that patients may not require as aggressive monitoring as is currently provided for those with tSAH.  相似文献   
37.
Objective: The present study reports on the application of a Swedish translation of the audiologist occupational stress questionnaire (AOSQ) on audiologists working in Sweden. The relations between AOSQ scores and perceived effort, perceived rewards, coping strategies at work, demographic variables such as salary, education length, practise length, and practice type were tested. Design: A cross-sectional e-mail survey using the AOSQ, effort-reward imbalance questionnaire, and demographic questions. Study sample: Four-hundred and four Swedish licensed audiologists working with clients. Results: The Swedish AOSQ translation demonstrated high inter-item correlations and high internal consistency. Several stress factors were identified: time spent at work, accountability, leadership at the workplace, paperwork and practice demands, equipment and clinical protocols, own health concerns, and job control. The outcome on the complete AOSQ questionnaire was related to perceived effort, perceived rewards, coping strategies at work, and age. Conclusions: The Swedish AOSQ translation seems to provide a valid measure of occupational stress among audiologists.  相似文献   
38.
39.
Nanoscaled quantum dots (QDs), with unique optical properties have been used for the development of theranostics. Here, InP/ZnS QDs were synthesised and functionalised with folate (QD-FA), D-glucosamine (QD-GA) or both (QD-FA-GA). The bi-functionalised QDs were further conjugated with doxorubicin (QD-FA-GA-DOX). Optimum Indium to fatty acid (In:MA) ratio was 1:3.5. Transmission electron microscopy (TEM) micrographs revealed spherical morphology for the QDs (11?nm). Energy-dispersive spectroscopy (EDS) spectrum confirmed the chemical composition of the QDs. MTT analysis in the OVCAR-3 cells treated with bare QDs, QD-FA, QD-GA, QD-FA-GA and QD-FA-GA-DOX (0.2?mg/mL of QDs) after 24?h indicated low toxicity for the bare QDs and functionalised QDs (about 80–90% cell viability). QD-FA-GA-DOX nanoparticles elicited toxicity in the cells. Cellular uptake of the engineered QDs were investigated in both folate receptor (FR)-positive OVCAR-3 cells and FR-negative A549 cells using fluorescence microscopy and FACS flow cytometry. The FA-functionalised QDs showed significantly higher uptake in the FR-positive OVCAR-3 cells, nonetheless the GA-functionalised QDs resulted in an indiscriminate uptake in both cell lines. In conclusion, our findings indicated that DOX-conjugated FA-armed QDs can be used as theranostics for simultaneous imaging and therapy of cancer.  相似文献   
40.
Objective: Alternative medicine and herbal drugs have been taken into account for managing cardiovascular risk factors. Sumac (Rhus coriaria L.) is rich in biologically active ingredients known to improve cardiovascular health. We investigated the effect of sumac on systolic (SBP) and diastolic (DBP) blood pressure, flow-mediated dilation (FMD), body mass index (BMI), and serum concentrations of lipids and fasting blood sugar (FBS) in participants with hyperlipidemia in a triple-blind randomized placebo- controlled crossover trial.

Methods: Thirty adults with dyslipidemia (mild to moderate elevation of plasma total cholesterol and/or triglycerides [TG; total cholesterol ≥ 6.0 mmol/L or TG ≥ 1.7 mmol/L and TG ≤ 5.0 mmol/L]) were assigned randomly to a sumac or a placebo group. Participants in the sumac group received sumac capsules (500 mg/twice daily) for the first 4 weeks, followed by 2 weeks’ washout period; the patients were then switched to a 4-week interval and received placebo for 4 weeks in the second period. The placebo group received these treatments in reverse order. FMD, BMI, SBP, DBP, lipids, and FBS were measured at baseline and after each period.

Results: Differences between placebo group and sumac group (placebo-sumac) were significantly decreased for BMI (0.21 ± 0.075 kg/m2), SBP (1.87 ± 0.83 mm Hg), DBP (1.32 ± 0.46 mm Hg), and total cholesterol (14.42 ± 4.95 mmol/L) and significantly increased for FMD (?0.23% ± 0.065%). Plasma level of TG did not change significantly across the treatment.

Conclusion: Sumac consumption may decrease cardiovascular risk factors in persons with mild to moderate hyperlipidemia.  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