全文获取类型
收费全文 | 2437111篇 |
免费 | 186244篇 |
国内免费 | 6992篇 |
专业分类
耳鼻咽喉 | 31993篇 |
儿科学 | 80366篇 |
妇产科学 | 68639篇 |
基础医学 | 351659篇 |
口腔科学 | 66580篇 |
临床医学 | 229498篇 |
内科学 | 475236篇 |
皮肤病学 | 52951篇 |
神经病学 | 201787篇 |
特种医学 | 90531篇 |
外国民族医学 | 790篇 |
外科学 | 349854篇 |
综合类 | 56186篇 |
现状与发展 | 4篇 |
一般理论 | 896篇 |
预防医学 | 202247篇 |
眼科学 | 54621篇 |
药学 | 175827篇 |
7篇 | |
中国医学 | 5681篇 |
肿瘤学 | 134994篇 |
出版年
2021年 | 19113篇 |
2019年 | 20324篇 |
2018年 | 28493篇 |
2017年 | 21617篇 |
2016年 | 24042篇 |
2015年 | 27128篇 |
2014年 | 38074篇 |
2013年 | 58003篇 |
2012年 | 79052篇 |
2011年 | 83897篇 |
2010年 | 49073篇 |
2009年 | 46183篇 |
2008年 | 77184篇 |
2007年 | 81621篇 |
2006年 | 82289篇 |
2005年 | 79646篇 |
2004年 | 75893篇 |
2003年 | 72444篇 |
2002年 | 69952篇 |
2001年 | 114017篇 |
2000年 | 117171篇 |
1999年 | 97753篇 |
1998年 | 27994篇 |
1997年 | 25408篇 |
1996年 | 25244篇 |
1995年 | 24080篇 |
1994年 | 22164篇 |
1993年 | 20809篇 |
1992年 | 75807篇 |
1991年 | 73450篇 |
1990年 | 71163篇 |
1989年 | 67600篇 |
1988年 | 62532篇 |
1987年 | 60888篇 |
1986年 | 57444篇 |
1985年 | 54796篇 |
1984年 | 41605篇 |
1983年 | 35402篇 |
1982年 | 21558篇 |
1981年 | 19077篇 |
1979年 | 37492篇 |
1978年 | 26549篇 |
1977年 | 22018篇 |
1976年 | 21165篇 |
1975年 | 21685篇 |
1974年 | 26386篇 |
1973年 | 25746篇 |
1972年 | 23802篇 |
1971年 | 21972篇 |
1970年 | 20694篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
951.
952.
953.
Neal G Palmer James R Yacyshyn Herbert C Northcott Brian Nebbe Paul W Major 《American journal of orthodontics and dentofacial orthopedics》2005,128(2):163-167
INTRODUCTION: To plan for future acceptance and implementation of computer-related technology, it is necessary to understand orthodontists' current perceptions and attitudes toward emerging technologies. METHODS: An anonymous, self-administered, mail-out survey of Canadian orthodontists was conducted. The response rate was 45.6% (304/667). RESULTS: Most orthodontists indicated that computer technology could improve current practice efficiency and quality of patient care. Only 15% reported that digital models are quite or very useful; 73.6%, 69.1%, 55%, and 37.4% agreed or strongly agreed with using digital and electronic technology to consult with other dental specialists, other orthodontists, general dentists, and the public, respectively. Cost of the technology was reported as a significant or insurmountable obstacle by 54% of the respondents. Interprovincial legislation, unclear consultation remuneration guidelines, and lack of comfort with the technology were not perceived as significant obstacles. Only 36% reported security or privacy issues as a significant or insurmountable obstacle. CONCLUSIONS: Canadian orthodontists seem to view digital and electronic technology as useful and capable of improving their offices' efficiency and production. Although they are sensitive to some potential obstacles, they are willing to overcome these and incorporate the technology into their practices. 相似文献
954.
A I Lukash A A Ananian L G Mendzheritskaia E E Nikolaeva V L Kesel'man V V Vnukov 《Anesteziologiia i reanimatologiia》1991,(2):27-30
Extra-erythrocyte hemoglobin (EEH) level and total peroxidase activity (TPA) have been analysed in the blood serum and plasma of 44 patients following hyperbaric oxygenation (HBO). The levels of the parameters tested decreased after 3 HBO procedures and remained low to the end of the treatment period in the first group of patients. In the second group of patients, on the contrary, EEH and TPA levels increased after 3 HBO procedures and remained high to the end of the treatment period. In both groups of patients EEH changes correlated with TPA alterations. Possible EEH and TPA determination for the estimation and enhancement of HBO treatment efficacy is discussed. 相似文献
955.
The purpose of the study was to compare skin blood flow by laser Doppler flowmetry (LDF) and the 133-Xenon washout technique in UVB-inflamed human skin. Six healthy subjects participated in the study. Forearm skin blood flow was measured prior to irradiation and then 8, 24, 48 and 72 h after the exposure to twice the minimal erythema dose of UVB. Baseline blood flow as measured by the 133-Xenon washout method was 5.2 (range 3.0 to 10.4) ml/100g/min and LDF flux was 3.1 (range 2.7 to 5.7) arbitrary units. Following irradiation, maximum blood flow increase as evaluated by the 133-Xenon washout was 10.8 (95% confidence interval 3.7 to 11.3) times baseline blood flow, corresponding to an absolute blood flow of 47.5 (range 33.8 to 56.3) ml/100g/min. Maximum increase after induction of inflammation as assessed by LDF was 34.6 (95% confidence interval 24.6 to 56.5) times baseline flux. The two methods showed comparable time courses in all subjects. A significant correlation between the two methods was found, Spearman's rho = 0.54, p = 0.006. The relative LDF blood flow increase was 4.2-fold (95% confidence interval 2.7 to 5.0) greater than the increase measured by the 133-Xenon washout method. These results are at variance with previous comparative studies of the two methods. Some explanations are discussed. 相似文献
956.
957.
Kindling is a process in which episodic electrical stimulation permanently increases seizure susceptibility. One mechanism to account for a change in seizure susceptibility is some alteration in signal transduction, possibly at the level of second messenger systems. In this study, male Long-Evans rats were kindled in the amygdala, and Ca2+/calmodulin (Ca2+/CaM)-dependent protein phosphorylation was assessed at the site of the primary kindled focus using one- and two-dimensional gel electrophoresis. In vitro phosphorylation of membrane and cytosol fractions in the presence of absence of Ca2+/CaM did not differentiate kindled from nonkindled amygdaloid tissue. These results suggest that changes in Ca2+/CaM-dependent phosphorylation are not related to the mechanism(s) underlying the establishment of an amygdaloid kindled focus. 相似文献
958.
M Battaglia M Gasperini G Sciuto P Scherillo G Diaferia L Bellodi 《Schizophrenia bulletin》1991,17(4):659-668
In a study of the families of 21 schizotypal patients, we found an increased morbidity risk for schizophrenia compared with that in the families of 21 nonschizotypal patients and 42 controls. The Axis I diagnoses did not influence the distribution of the morbidity risk in the families of the schizotypal patients. If the schizotypal subjects also had other personality disorders, the morbidity risk for schizophrenia among their relatives was lower, although not significantly. 相似文献
959.
960.
Glass ionomer restorative cement offers the clinician an alternative to bonded composite resin for restoration of certain lesions in primary teeth. This article details a step-by-step procedure for restoration of a smooth surface carious lesion in a primary incisor using an encapsulated glass ionomer restorative material and reviews advantages and limitations of the cement. A light-hardened glass ionomer liner/base that has proven useful as an enamel and dentin restorative is also described. 相似文献