全文获取类型
收费全文 | 3502485篇 |
免费 | 280121篇 |
国内免费 | 31112篇 |
专业分类
耳鼻咽喉 | 48425篇 |
儿科学 | 105883篇 |
妇产科学 | 89004篇 |
基础医学 | 482246篇 |
口腔科学 | 95489篇 |
临床医学 | 336961篇 |
内科学 | 659272篇 |
皮肤病学 | 69346篇 |
神经病学 | 276913篇 |
特种医学 | 138501篇 |
外国民族医学 | 1525篇 |
外科学 | 506453篇 |
综合类 | 142907篇 |
现状与发展 | 88篇 |
一般理论 | 1262篇 |
预防医学 | 278619篇 |
眼科学 | 83949篇 |
药学 | 274233篇 |
438篇 | |
中国医学 | 30102篇 |
肿瘤学 | 192102篇 |
出版年
2021年 | 39167篇 |
2019年 | 34208篇 |
2018年 | 43946篇 |
2017年 | 36067篇 |
2016年 | 37606篇 |
2015年 | 47020篇 |
2014年 | 64301篇 |
2013年 | 85668篇 |
2012年 | 118451篇 |
2011年 | 127348篇 |
2010年 | 77916篇 |
2009年 | 71513篇 |
2008年 | 112236篇 |
2007年 | 118110篇 |
2006年 | 117927篇 |
2005年 | 114463篇 |
2004年 | 104911篇 |
2003年 | 101548篇 |
2002年 | 97949篇 |
2001年 | 152943篇 |
2000年 | 158067篇 |
1999年 | 135278篇 |
1998年 | 41945篇 |
1997年 | 38367篇 |
1996年 | 37228篇 |
1995年 | 35822篇 |
1994年 | 33226篇 |
1993年 | 30149篇 |
1992年 | 104979篇 |
1991年 | 101851篇 |
1990年 | 98247篇 |
1989年 | 94407篇 |
1988年 | 87297篇 |
1987年 | 85929篇 |
1986年 | 80973篇 |
1985年 | 77259篇 |
1984年 | 58474篇 |
1983年 | 49729篇 |
1982年 | 29901篇 |
1979年 | 54310篇 |
1978年 | 38022篇 |
1977年 | 32163篇 |
1976年 | 30220篇 |
1975年 | 32113篇 |
1974年 | 39154篇 |
1973年 | 37315篇 |
1972年 | 34792篇 |
1971年 | 32006篇 |
1970年 | 30305篇 |
1969年 | 28041篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
991.
Background
A standardised suction technique has been used to sample plasma proteins in dermal interstitial fluid (IF) serially for 5 to 6 days from a suction-induced skin mini-erosion. Increased protein concentrations ascribed to inflammation have been shown from day 1 onward. In this study, we assessed the effect of two different extraction pressures on IF sample composition. 相似文献992.
Christine M Sapienza Michael P Cannito Thomas Murry Ryan Branski Gayle Woodson 《J. Speech Lang. Hear. Res.》2002,45(5):830-843
Acoustic analysis of a reading passage was used to identify the abnormal phonatory events associated with adductor spasmodic dysphonia (ADSD) pre- and postinjection of Botulinum Toxin A (Botox). Thirty-one patients (age 22 to 74 years) diagnosed with ADSD were included for study. All patients were new recipients of Botox, and the examination of their voice occurred before and after their initial injection of Botox. Acoustic events were identified from reading samples of the Rainbow Passage produced by each of the patients. These events were examined from sentences containing primarily voiced sound segments. Dependent variables included the number of phonatory breaks, frequency shifts, and aperiodic segments--all variables previously defined by the investigators. Additionally, calculated variables were made of the percentage of time these events occurred relative to the duration of the cumulative voiced segments. A sex- and age-matched control group (+/-2 years) was included for statistical comparison. Results indicated that those with ADSD produced more aberrant acoustic events than the controls. Aperiodicity was the predominant acoustic event produced during the reading, followed by frequency shifts and phonatory breaks. Within the ADSD group, the number of atypical acoustic events decreased following Botox injection. It is important that the occurrence of specific abnormal acoustic events was sufficient to differentiate the disordered speakers from the controls following as well as preceding initial Botox injection, as indicated by discriminant function analysis. This paper complements our previous work using this acoustic analysis method for defining the abnormal events present in the voice of those with ADSD and further suggests that these measures can be used in conjunction with perceptual impressions to differentiate speakers on the basis of initial severity. 相似文献
993.
994.
Adolescent stress is an emerging area of importance in considerations of the health of young people. Exposure to stress predicts a range of both physical and mental health problems in adolescents and relates, as well, to the initiation of important health risk behaviours. Yet the measurement of stress in adolescents has been as fraught with methodological difficulty as it has been for adults. This paper examines the Adolescent Stress Questionnaire (ASQ) which was developed specifically to address the domain of stressors specific to adolescent experience and looks at three cohorts of responses to this questionnaire over time (1995, 1998 and 2001). It assesses the stability of the original 7‐factor structure of the ASQ over time, and while confirmatory factor analysis indicates that stability to be acceptable, it also suggests that either adolescent stressors themselves, or the language by which they are reported, vary sufficiently over time to warrant the refinement of the instrument. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
995.
996.
997.
998.
Michael S Benninger Peter C Appelbaum James C Denneny David J Osguthorpe James A Stankiewicz 《Otolaryngology--head and neck surgery》2002,127(1):7-12
OBJECTIVE: Traditional assessments of the microbial flora associated with acute bacterial rhinosinusitis have relied on maxillary sinus punctures (taps) and culture. These taps are now considered the gold standard for obtaining cultures and are used as the method of identifying bacterial pathogens in antimicrobial trials. Maxillary sinus taps are limited by discomfort to the patients and technical concerns. Because of these factors, the standard of performing taps has limited antibiotic trials and microbial surveillance. Alternatives to maxillary sinus taps have been explored. STUDY DESIGN: We conducted a retrospective, systematic review of the literature from 1950 to 2000 of articles comparing culture techniques in the nose and paranasal sinuses for acute bacterial rhinosinusitis. RESULTS: Nasal cultures have poor correlation to maxillary sinus cultures, whereas there is 60% to 85% concordance between endoscopically guided middle meatal cultures and maxillary sinus cultures. These studies, however, are all limited by small sample sizes and therefore are inadequate to make any concrete recommendations regarding the relative role of endoscopically guided middle meatal cultures as a formal method of pathogen identification in acute bacterial rhinosinusitis. CONCLUSION: A formal prospective study with sufficient sample size to assess the concordance between the microbial flora of the maxillary sinus punctures and middle meatal cultures in acute rhinosinusitis is recommended. 相似文献
999.
Comparison of ThinPrep versus conventional smear cytopreparatory techniques for fine-needle aspiration specimens of head and neck masses. 总被引:2,自引:0,他引:2
Lloyd Ford Barry M Rasgon Raymond L Hilsinger Raul M Cruz Karen Axelsson Gregory J Rumore Thomas M Schmidtknecht Balaram Puligandla John Sawicki William Pshea 《Otolaryngology--head and neck surgery》2002,126(5):554-561
OBJECTIVES: Diagnostic accuracy of the ThinPrep process (Cytyc, Boxborough, MA) was compared with that of conventional (smear) cytopreparation for fine-needle aspiration (FNA) of head and neck masses. METHODS: In a prospective, randomized, single-blinded study, 209 patients served as their own controls and underwent 236 FNAs using ThinPrep and conventional (smear) cytopreparatory techniques. RESULTS: ThinPrep produced less air-drying artifact and less mechanical distortion than the conventional method. The conventional technique was diagnostic in 63% of samples; the ThinPrep technique was diagnostic in 55% of samples. When all results were combined, pathologists subjectively preferred the conventional technique but accepted use of ThinPrep as the only cytopreparatory technique for most head and neck masses. CONCLUSIONS: For adequately experienced cytopathologists, ThinPrep is acceptable for FNA of salivary masses, neck cysts, metastatic lymph nodes, and thyroid lesions. Conventional smear technique should be used for FNA of nonmetastatic lymphoid lesions. Use of ThinPrep can complement use of the conventional (smear) cytopreparatory technique when aspirate is nondiagnostic or bloody, when the patient has a blood-borne infectious disease, when the clinician is inexperienced, or when aspirate has entered the syringe. 相似文献
1000.
目的:探讨EB病毒感染与人大肠癌发生的关系。方法:用原位分子杂交法对130例人大肠癌标本中EB病毒小分子RNA片段进行检测。结果:130例标本中有6例(4.48%)癌组织呈阳性反应,其中4例为男性,4例有明显淋巴细胞浸润。结论:EB病毒感染可能与我国部分大肠腺癌的发生有关,肿瘤细胞间质中大量淋巴细胞浸润可能是EB病毒感染的重要病理学特征。 相似文献