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   741334篇
  免费   57848篇
  国内免费   28314篇
耳鼻咽喉   7911篇
儿科学   12953篇
妇产科学   14074篇
基础医学   92238篇
口腔科学   17515篇
临床医学   81905篇
内科学   126726篇
皮肤病学   12366篇
神经病学   44646篇
特种医学   27309篇
外国民族医学   306篇
外科学   92024篇
综合类   78829篇
现状与发展   87篇
一般理论   95篇
预防医学   44394篇
眼科学   19732篇
药学   70528篇
  434篇
中国医学   26338篇
肿瘤学   57086篇
  2023年   6059篇
  2022年   15479篇
  2021年   20706篇
  2020年   15914篇
  2019年   14174篇
  2018年   16320篇
  2017年   14844篇
  2016年   13984篇
  2015年   20464篇
  2014年   26190篇
  2013年   25983篇
  2012年   37705篇
  2011年   41444篇
  2010年   27300篇
  2009年   22992篇
  2008年   30318篇
  2007年   30755篇
  2006年   29819篇
  2005年   28105篇
  2004年   21153篇
  2003年   20462篇
  2002年   17958篇
  2001年   35805篇
  2000年   36159篇
  1999年   31245篇
  1998年   10136篇
  1997年   9131篇
  1996年   7692篇
  1995年   7113篇
  1994年   6162篇
  1993年   4800篇
  1992年   18162篇
  1991年   16657篇
  1990年   15704篇
  1989年   15268篇
  1988年   13648篇
  1987年   13004篇
  1986年   11857篇
  1985年   10838篇
  1984年   7188篇
  1983年   5800篇
  1982年   2827篇
  1979年   5591篇
  1978年   3406篇
  1977年   3017篇
  1975年   2668篇
  1974年   3102篇
  1973年   2897篇
  1972年   2857篇
  1971年   2791篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
52.
放射治疗在杀死肿瘤细胞的同时,对肿瘤周围器官的细胞和组织也有杀伤作用,从而引起近期放疗反应和远期并发症。  相似文献   
53.
Opportunistic infections in the oral cavity of the elderly may increase the incidence of systemic disease. The objective of this study was to investigate the differences in the oral bacterial flora between dependent elderly (inpatients) and independent elderly (community-dwelling residents). After multiple variables were taken into account, inpatients had significantly lower detection rates than community-dwelling residents for alpha-streptococci (p < 0.001) and Neisseria (p 0.004), and higher detection rates for Pseudomonas aeruginosa (p 0.024), methicillin-resistant Staphylococcus aureus (MRSA) (p 0.011) and Actinomyces spp. (p 0.005). Among inpatients, the requirement for a high degree of care was related negatively to detection of alpha-streptococci, but was related significantly to detection of P. aeruginosa (p 0.018) or MRSA (p 0.004). Tube-fed inpatients had a significantly lower detection rate for alpha-streptococci (p 0.041) and a higher detection rate for P. aeruginosa (p 0.004) than those who did not require tube feeding. Inpatients with a history of antibiotic use had a significantly lower detection rate for alpha-streptococci (p 0.049) and a higher detection rate for MRSA (p 0.007) than those without a history of antibiotic use. The detection rates for P. aeruginosa or MRSA in inpatients without alpha-streptococci were higher than in inpatients with alpha-streptococci after controlling for age and gender (P. aeruginosa, p 0.006; MRSA, p 0.001). Overall, detection of alpha-streptococci had an inverse correlation with the detection of P. aeruginosa and MRSA in the oral cavity and is likely to be an indicator of pathogenic bacterial infection.  相似文献   
54.
李宗庭 《中医研究》2006,19(10):51-52
慢性萎缩性胃炎是以胃黏膜上皮和腺体萎缩、黏膜变薄为特征的慢性疾病。属中医胃脘痛、胃痞等范畴。其病因病机较为复杂,多与饮食不调、情志不畅有关,尤其是饮酒、过食刺激之品,致使脾胃受损,阳气郁遏不振,纳运失司,化源不足,气血阴液亏乏;或中焦运化无力,湿邪滞塞,郁而化热;或  相似文献   
55.
In order to assess the state and pathology of the woman's pelvis minor, a number of methods are commonly used among practitioners, encompassing clinical exploration, radiology, MRN, urodynamics, endoscopy and echography.

Echography has been poorly used in clinical pelvic exploration and its reliability is actually a matter of controversy 1. However, echographic surveys can provide us with valuable gynecological data on the state and pathologies of the soft pelvis, within the genital regions or even going beyond them, i.e. the rectal channel, bladder, urethra, anus, vascular plexuses, and all of their supporting tissues.

At our research unit, we have been employing Transvaginal Ultrasound echography (TVU) for a long time in conjunction with other pelvis-focused methods in order to study different kinds of pelvic alterations. TVU has proven to be friendly to use, fast, harmless and inexpensive, allowing serial explorations and producing high-quality dynamic images (loop-cinema, video-tape). Furthermore, this method is fairly aseptic in that the occurrence of faeces in the rectal ampolla is not a nuisance but a bonus in tracking the contours of the rectum walls and other topographical features which would be otherwise difficult to survey.

A complete pelvic floor TVU may add no longer than 5-8 minutes to a routine gynecological examination, can be implemented by the general gynecologist and generates data that can be further studied by the appropriate specialist for a more insightful evaluation 2.  相似文献   
56.
PURPOSE: The aim of this study was to determine the reproducibility of measurements made using the Sonogage Corneo-Gage Plus 2 (Cleveland, Ohio) ultrasound pachymeter of total corneal and corneal epithelial thickness in 5 different regions of the cornea. METHODS: Twenty-seven subjects at the New England College of Optometry (NECO) and 20 subjects at the Southern College of Optometry (SCO) were enrolled in this study. Measurements were taken of the central cornea as well as the nasal and temporal regions of the midperipheral and peripheral regions of the right cornea of each subject. Identical measurements were again taken in these subjects 1 week later at approximately the same time of day. Within-subject variations were then assessed using paired t tests. RESULTS: The only significant measurement differences that were found between visits were for full corneal thickness at both the nasal and temporal midperipheral locations. The mean differences for these locations were 13.5 microm and 13.7 microm, respectively. CONCLUSIONS: Epithelial corneal thickness and central and peripheral total corneal thickness measurements using the Corneo-Gage Plus 2 pachymeter were reproducible; however, midperipheral total corneal thickness measurements showed poor reproducibility.  相似文献   
57.
58.
59.
表皮生长因子对牛眼小梁细胞c—fos基因表达的诱导   总被引:4,自引:0,他引:4  
目的研究表皮生长因子(epidermalgrowthfactor,EGF)对小梁细胞的作用。方法应用分子杂交技术研究EGF对体外培养的牛眼小梁细胞c-fos基因表达的诱导和3H胸腺核苷酸(3H-thymidineincorparation,3H-TdR)掺入法观察细胞DNA的合成。结果小梁细胞的3H-TdR掺入率随着EGF浓度不同而变化,浓度为20~150ng/ml时,细胞掺入率随浓度增加升高(P<0.01)。与对照组相比,EGF刺激停止生长的小梁细胞0.5小时后,c-fos基因开始表达,1小时后达高峰,至2小时后消失。不同浓度EGF刺激小梁细胞1小时后,c-fos基因表达呈浓度依赖性。结论实验结果表明EGF刺激小梁细胞增殖或进入生长状态,可能与c-fos基因产物的信号传递作用有关。  相似文献   
60.
Membrane-bound CD14 acts as a receptor for lipopolysaccharide (LPS) on monocytes/macrophages and neutrophils. Studies have suggested that the activation of monocytes/macrophages by the binding of LPS to membrane-bound CD14 may require the association of a signal-transducing molecule with membrane-bound CD14. The observation that non-CD14 expressing cells, such as endothelial cells, can nevertheless be activated by a complex of LPS and a soluble form of CD14 (sCD14) suggests that the receptor for this complex may be identical to the signal transducing molecule associated with membrane-bound CD14. The studies described show that two CD14-specific MoAb are able to block the LPS-induced activation of endothelial cells but do not affect the response of monocytes to LPS. This suggests that the interaction of the sCD14:LPS complex with endothelial cells is distinct from the interaction of membrane-bound CD14 with its putative signal-transducing molecule.  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