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   39359篇
  免费   2691篇
  国内免费   961篇
耳鼻咽喉   102篇
儿科学   586篇
妇产科学   321篇
基础医学   5183篇
口腔科学   651篇
临床医学   2751篇
内科学   4475篇
皮肤病学   232篇
神经病学   3824篇
特种医学   1013篇
外国民族医学   2篇
外科学   1467篇
综合类   3083篇
现状与发展   2篇
预防医学   3888篇
眼科学   148篇
药学   10186篇
  12篇
中国医学   3644篇
肿瘤学   1441篇
  2024年   101篇
  2023年   542篇
  2022年   1001篇
  2021年   1363篇
  2020年   1224篇
  2019年   1225篇
  2018年   1196篇
  2017年   1304篇
  2016年   1226篇
  2015年   1159篇
  2014年   1986篇
  2013年   3207篇
  2012年   1760篇
  2011年   2180篇
  2010年   1455篇
  2009年   1736篇
  2008年   1721篇
  2007年   1696篇
  2006年   1432篇
  2005年   1276篇
  2004年   1117篇
  2003年   1010篇
  2002年   892篇
  2001年   854篇
  2000年   645篇
  1999年   658篇
  1998年   666篇
  1997年   577篇
  1996年   562篇
  1995年   536篇
  1994年   458篇
  1993年   444篇
  1992年   450篇
  1991年   413篇
  1990年   386篇
  1989年   391篇
  1988年   347篇
  1987年   338篇
  1986年   326篇
  1985年   444篇
  1984年   400篇
  1983年   279篇
  1982年   352篇
  1981年   276篇
  1980年   284篇
  1979年   208篇
  1978年   221篇
  1977年   159篇
  1976年   194篇
  1975年   79篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Objective: To develop and field-test a physical performance measure (MPS-PPM) for individuals with Mucopolysaccharidosis I (MPS I), a rare genetic disorder. Methods: Motor performance and endurance items were developed based on literature review, clinician feedback, feasibility, and equipment and training needs. A standardized testing protocol and scoring rules were created. The MPS-PPM includes: Arm Function (7 items), Leg Function (5 items), and Endurance (2 items). Pilot data were collected for 10 subjects (ages 5–29 years). We calculated Spearman's rho correlations between age, severity and summary z-scores on the MPS-PPM. Results: Subjects had variable presentations, as correlations among the three sub-test scores were not significant. Increasing age was related to greater severity in physical performance (r = 0.72, p<0.05) and lower scores on the Leg Function (r = ?0.67, p<0.05) and Endurance (r = ?0.65, p<0.05) sub-tests. The MPS-PPM was sensitive to detecting physical performance deficits, as six subjects could not complete the full battery of Arm Function items and eight subjects were unable to complete all Leg Function items. Subjects walked more slowly and expended more energy than typically developing peers. Conclusions: Individuals with MPS I have difficulty with arm and leg function and reduced endurance. The MPS-PPM is a clinically feasible measure that detects limitations in physical performance and may have potential to quantify changes in function following intervention.  相似文献   
952.
Background Behaviours regarding food and activity are learned during childhood and continue throughout life. Children can be very important agents in making decisions concerning their own well‐being and care and their perspective is essential to understanding how they and/or others make choices for them to achieve a healthy lifestyle. However, their perspectives remain under‐researched. This study provides an insight into school children's own perspectives, behaviours and contribution to food and activity choices. Methods The paper reports on the findings from an ethnographic study with 38 Spanish children aged 5–7 years. Information was obtained through participant observations, diaries kept by children and group interviews. Data were analysed using techniques of analytical induction and constant comparison. Results The children who took part in this study described choices about activities with enthusiasm. Children saw activity as a way of learning new things, mastering skills and socializing. They were willing to try and experience new activities and games. However, the activities performed depended on parents' agendas and security issues. In contrast, children reported less interest in and active involvement in food choices. They contributed to family food choices indirectly through the expression of their preferences, not wanting to eat what they disliked or tasting new foods. Conclusion Children had strong preferences and motivations, particularly about activities which could be harnessed in interventions to prevent obesity and promote healthy diet and activity. Parental involvement and commitment is also important both to encourage exercise according to children's interests and active informed food choices, including introduction to unfamiliar foods.  相似文献   
953.
Abstract

Bucillamine (Buc), developed in Japan, is a disease-modifying antirheumatic drug (DMARD) which has been used to treat numerous patients with rheumatoid arthritis (RA) in Japan and Korea with favorable results. However, it has not been used globally. In the present study, we compared the timing of onset of efficacy and the usefulness of this drug with that of the globally accepted agent salazosulfapyridine (SASP). There were 26 patients in the Buc group and 23 in the SASP group. We compared changes in the number of swollen joints, number of painful joints, duration of morning stiffness, grip strength, levels of inflammatory marker [erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)], rheumatoid factor (RF), physician’s rating by visual analogue scale (VAS), patient’s rating of pain, patient’s overall rating (VAS), and improvement according to European League against Rheumatism (EULAR) criteria (DAS28-CRP, DAS28-ESR) in these two groups of patients. Both Buc and SASP were shown to be efficacious within 3 months after the start of treatment. Both drugs were found to be suitable as first-line treatment of early RA. Signs of efficacy tended to occur earlier with Buc than with SASP, and Buc also tended to have higher efficacy than SASP.  相似文献   
954.
Climate change has led to increased frequency, intensity, and duration of extreme heat events with dire consequences for health. These are the deadliest of climate change impacts with preventable mortality from heat-related illnesses and increased threat to safe participation in physical activity and sports. Nurse practitioners can collaborate with community and professional sports health organizations to ensure evidence-based health and safety policies to reduce health-related risks. Adverse consequences on engagement in key health-promoting physical activity and sports may catalyze urgent action to address climate change.  相似文献   
955.
956.
The interaction between tissues and biomaterials (BM) has the purpose of improving and replacing anatomical parts of the human body, avoiding the occurrence of adverse reactions in the host organism. Unfortunately, the early failure of implants cannot be currently avoided, since neither a good mixture of mechanical and chemical characteristics of materials nor their biocompatibility has been yet achieved. Bioactive glasses are recognized to be a fine class of bioactive substances for good repair and replacement. BM interact with living bones through the formation of a hydroxyapatite surface layer that is analogous to bones. Bioglasses’ composition noticeably affects their biological properties, as does the synthesis method, with the best one being the versatile sol-gel technique, which includes the change of scheme from a ‘sol’ fluid into a ‘gel’. This process is widely used to prepare many materials for biomedical implants (e.g., hip and knee prostheses, heart valves, and ceramic, glassy and hybrid materials to serve as carriers for drug release). Nanoparticles prepared by the sol-gel method are interesting systems for biomedical implementations, and particularly useful for cancer therapy. This review provides many examples concerning the synthesis and characterization of the above-mentioned materials either taken from literature and from recently prepared zirconia/polyethylene glycol (PEG) hybrids, and the corresponding results are extensively discussed.  相似文献   
957.
目的 制备高纯度3,5-O-二咖啡酰基奎宁酸,并评价其对人宫颈癌HeLa细胞的抗增殖活性。方法 采用柱色谱提取法和中压液相色谱法从奇蒿花中分离、纯化得到高纯度的3,5-O-二咖啡酰基奎宁酸。采用MTT法评价该化合物对人宫颈癌HeLa细胞的体外抗增殖活性。结果 柱色谱提取的提取率和中压液相色谱法的回收率分别为99.0%,61.2%,总回收率为54.0%。随着3,5-O-二咖啡酰基奎宁酸浓度升高,HeLa细胞存活率下降,细胞形态损伤增加,受试药物的IC50值为26.5µg·mL-1结论 本研究提供了一种简单、高效、节能的3,5-O-二咖啡酰基奎宁酸制备方法。3,5-O-二咖啡酰基奎宁酸对HeLa细胞具有一定的体外抗增殖活性。  相似文献   
958.
《药学学报(英文版)》2019,9(6):1193-1203
EGFR tyrosine kinase inhibitor (EGFR-TKI) has been used successfully in clinic for the treatment of solid tumors. In the present study, we reported the discovery of WS-157 from our in-house diverse compound library, which was validated to be a potent and selective EGFR-TKI. WS-157 showed excellent inhibitory activities against EGFR (IC50 = 0.81 nmol/L), EGFR[d746−750] (IC50 = 1.2 nmol/L) and EGFR[L858R] (IC50 = 1.1 nmol/L), but was less effective or even inactive against other nine kinases. WS-157 also displayed excellent antiproliferative activities against a panel of human cancer cell lines, and exhibited the ability to reduce colony formation and wound healing the same as gefitinib. We found that WS-157 upon oral administration showed better anti-tumor activity in A431 bearing xenograft mouse models compared to gefitinib. In addition, WS-157 showed better intestinal absorption than gefitinib and had favorable pharmacokinetic properties and microsomal metabolic stability in different species. These studies indicate that WS-157 has strong antitumor activity in vitro and in vivo, and could be used for the development of anti-lung cancer agent targeting EGFR.  相似文献   
959.
Activity spaces are increasingly used to understand how people interact with their environment and engage in activity but their use may raise challenges regarding causal inference. We conducted a systematic review of findings and the methodological, analytical and conceptual issues relevant to causal inference. Studies were included if they comprised a spatial summary of locations visited, assessed any part of the causal pathway between the environment, physical activity and health, and used quantitative or qualitative methods. We searched seven electronic databases in January 2018 and screened 11910 articles for eligibility. Forty-seven studies were included for review. Studies answered research questions about features of or environmental features within activity spaces using a range of spatial and temporal summary techniques. The conceptual challenge of using activity spaces to strengthen causal inference was rarely considered, although some studies discussed circularity, temporality, and plausibility. Future studies should use longitudinal and experimental designs and consider the potential and actual use of spaces for physical activity, and their relationship with total levels of activity.  相似文献   
960.
Abstract

Background and Aims

DUBLIN score allows evaluation of disease activity and extent in ulcerative colitis (UC). This study aimed to evaluate DUBLIN score as a predictor of therapeutic failure as well as to associate endoscopic and histological activity scores to assess their joint performance.  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