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   22456篇
  免费   1802篇
  国内免费   369篇
耳鼻咽喉   232篇
儿科学   605篇
妇产科学   524篇
基础医学   2992篇
口腔科学   520篇
临床医学   2070篇
内科学   4220篇
皮肤病学   309篇
神经病学   1585篇
特种医学   884篇
外国民族医学   1篇
外科学   3652篇
综合类   1342篇
现状与发展   4篇
一般理论   8篇
预防医学   1282篇
眼科学   636篇
药学   1478篇
  2篇
中国医学   450篇
肿瘤学   1831篇
  2023年   237篇
  2022年   362篇
  2021年   676篇
  2020年   466篇
  2019年   610篇
  2018年   674篇
  2017年   508篇
  2016年   535篇
  2015年   668篇
  2014年   879篇
  2013年   1000篇
  2012年   1554篇
  2011年   1687篇
  2010年   957篇
  2009年   797篇
  2008年   1215篇
  2007年   1217篇
  2006年   1199篇
  2005年   1197篇
  2004年   1046篇
  2003年   965篇
  2002年   863篇
  2001年   743篇
  2000年   640篇
  1999年   550篇
  1998年   215篇
  1997年   218篇
  1996年   152篇
  1995年   169篇
  1994年   119篇
  1993年   106篇
  1992年   260篇
  1991年   226篇
  1990年   235篇
  1989年   231篇
  1988年   207篇
  1987年   203篇
  1986年   171篇
  1985年   127篇
  1984年   85篇
  1983年   69篇
  1981年   46篇
  1980年   44篇
  1979年   68篇
  1978年   56篇
  1977年   46篇
  1976年   37篇
  1975年   34篇
  1974年   32篇
  1973年   36篇
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
1.
2.
3.
4.
5.
6.
Phytonutrients extracted from natural resources are receiving much attention among researchers due to their highly antioxidative characteristics which prevent several degenerative diseases including cardiovascular diseases and cancers. These nutraceutical compounds can be used in food, pharmaceutical and cosmetic products as natural antioxidants, preservatives, colourants and functional foods. Huge volume of food wastes are generated from the processing industry and these low-value food residues are rich in various phytonutrients worth recovering. This approach of valorisation reduces the generation of food wastes and is cost-effective considering the cheap feedstock, reduced waste management expenses and high market value of extracted compounds. In light of the health and safety risks posed by commonly used organic extraction solvents derived from the petrochemical industry, there is a need to recover the phytonutrients using green, sustainable and efficient solvents that are safe for human consumption. This work discusses ethyl lactate as a safe, green, efficient and potentially cheap solvent to recover phytonutrients from fruit and vegetable by-products. Ethyl lactate is compared with other organic solvents commonly used from the aspects of safety, environmental impacts and efficiency. Current challenges when employing ethyl lactate are also discussed.  相似文献   
7.
8.
Inflammation, an important contributory factor of muscle and bone aging, is potentially modulated by diet. This study examined the associations of dietary inflammatory index (DII) score with musculoskeletal parameters and related disease outcomes in 3995 community-dwelling Chinese men and women aged ≥65 years in Hong Kong. DII score at baseline was estimated from a food frequency questionnaire. Bone mineral density (BMD) and muscle mass estimated by dual-energy X-ray absorptiometry (DXA), hand grip strength, gait speed, and chair stand test were measured at baseline, year 4, and year 14. The associations of DII score with the longitudinal changes of musculoskeletal parameters, and incidence of osteoporosis, sarcopenia, and fractures were examined by using general linear model, multinomial logistic regression model, and Cox proportional hazards regression model, respectively. After multiple adjustments, each tertile increase in DII score in men was associated with 0.37 (95% confidence interval [CI], 0.10–0.64) kg loss in grip strength and 0.02 (95% CI, 0.01–0.03) m/s loss in gait speed over 4 years. In men, the highest tertile of DII was associated with a higher risk of incident fractures, with adjusted and competing death adjusted hazard ratio (HR) (95% CI) of 1.56 (1.14–2.14) and 1.40 (1.02–1.91), respectively. In women, DII score was not significantly associated with any muscle-related outcomes or incidence of fracture, but a significant association between higher DII score and risk of osteoporosis at year 14 was observed, with the highest tertile of DII score having adjusted odds ratio (OR) (95% CI) of 1.90 (1.03–3.52). In conclusion, pro-inflammatory diet consumption promoted loss of muscle strength and physical function, and increased risk of fractures in older Chinese men. Pro-inflammatory diets had no significant association with muscle related outcomes but increased the long-term risk of osteoporosis in older Chinese women. © 2022 American Society for Bone and Mineral Research (ASBMR).  相似文献   
9.
VAGAL paraganglioma VP)is an uncommonneoplasm originating from neural crest paragan-glion cells located along the vagus nerve,repre-senting less than5%of all paragangliomas of the head andneck.1Despite improvement in microsurgical techniques,management of…  相似文献   
10.
目的:评价东部身体-智力-精神(EBMS)群体干预对进行体外受精(IVF)的中国妇女焦虑缓解的作用。设计:随机对照研究。机构:三级辅助生殖机构。受试者:227例接受第1个IVF周期治疗的妇女。干预:干预组(n=69)接受4次EBMS群体咨询,而对照组(n=115)无任何干预。主要观察指标:状态-特质焦虑问卷。结果:与对照组相比,干预组在干预后状态焦虑平均分显著下降。每组移植同样数目的卵子,但干预组没有明显更高妊娠率的倾向。  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