全文获取类型
收费全文 | 137726篇 |
免费 | 12024篇 |
国内免费 | 7974篇 |
专业分类
耳鼻咽喉 | 1301篇 |
儿科学 | 1536篇 |
妇产科学 | 2113篇 |
基础医学 | 18488篇 |
口腔科学 | 2952篇 |
临床医学 | 16149篇 |
内科学 | 22855篇 |
皮肤病学 | 1769篇 |
神经病学 | 8396篇 |
特种医学 | 4816篇 |
外国民族医学 | 67篇 |
外科学 | 15582篇 |
综合类 | 18603篇 |
现状与发展 | 31篇 |
一般理论 | 8篇 |
预防医学 | 8085篇 |
眼科学 | 3863篇 |
药学 | 13562篇 |
68篇 | |
中国医学 | 5501篇 |
肿瘤学 | 11979篇 |
出版年
2024年 | 325篇 |
2023年 | 1824篇 |
2022年 | 4144篇 |
2021年 | 5179篇 |
2020年 | 3818篇 |
2019年 | 3620篇 |
2018年 | 4177篇 |
2017年 | 3665篇 |
2016年 | 3411篇 |
2015年 | 5002篇 |
2014年 | 6093篇 |
2013年 | 5686篇 |
2012年 | 8328篇 |
2011年 | 9105篇 |
2010年 | 5453篇 |
2009年 | 4446篇 |
2008年 | 5923篇 |
2007年 | 6340篇 |
2006年 | 6145篇 |
2005年 | 5963篇 |
2004年 | 4094篇 |
2003年 | 3828篇 |
2002年 | 3450篇 |
2001年 | 6302篇 |
2000年 | 6468篇 |
1999年 | 6218篇 |
1998年 | 2945篇 |
1997年 | 2524篇 |
1996年 | 1800篇 |
1995年 | 1546篇 |
1994年 | 1322篇 |
1993年 | 1002篇 |
1992年 | 2571篇 |
1991年 | 2230篇 |
1990年 | 2028篇 |
1989年 | 1902篇 |
1988年 | 1626篇 |
1987年 | 1468篇 |
1986年 | 1265篇 |
1985年 | 1055篇 |
1984年 | 656篇 |
1983年 | 520篇 |
1982年 | 282篇 |
1981年 | 219篇 |
1980年 | 166篇 |
1979年 | 303篇 |
1978年 | 77篇 |
1974年 | 75篇 |
1973年 | 95篇 |
1972年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
12.
Evaluation of adhesive strength of five dental adhesive cements and two visible light-activated composite resins 总被引:2,自引:0,他引:2
C X Zhang 《中华口腔医学杂志》1987,22(5):298-300
13.
14.
A. Jaén J. Sunyer X. Basagaña S. Chinn† J. P. Zock J. M. Antó‡ P. Burney† 《Clinical and experimental allergy》2002,32(12):1713-1719
BACKGROUND: The role of atopy in the evolution to chronic obstructive disease remains controversial. AIM: We aimed to assess the association between individual sensitization to common allergens and lung function. METHOD: We analysed data from 12,687 subjects aged 20 to 44 years, from 34 centres in 15 countries participating in the European Community Respiratory Health Survey (ECRHS). Participants performed a blood test, lung function test, methacholine challenge, and answered an administered questionnaire. The relationships between specific IgE, FEV1 and FEV1/FVC ratio were assessed for each study centre stratified by sex, followed by random effects meta-analysis. RESULTS: Asthmatics sensitized to house dust mite had a lower FEV1 (-119 mL in women and -112 mL in men) and FEV1/FVC ratio (-1.95%, and -2.48%) than asthmatics without sensitization. Asthmatics sensitized to cat had a lower FEV1 (statistically significant for women only) and a lower FEV1/FVC ratio. Asthmatic women sensitized to grass had a lower FEV1 and a lower ratio, and those sensitized to Cladosporium had a lower FEV1. A weak association was found with sensitization to cat and to Cladosporium among non-asthmatic women, which disappeared after adjusting for BHR. CONCLUSION: We conclude that atopy was related to a lower lung function, which was only apparent among asthmatics. This relationship was explained by specific sensitization to cat and to house dust mite, the latter being homogeneous across areas. 相似文献
15.
J Parinaud H Grandjean M F Sarramon J M Reme X Monrozies C Sarrazin G Pontonnier 《European journal of obstetrics, gynecology, and reproductive biology》1987,24(4):285-292
In order to ascertain the adequacy of ovarian stimulation protocols with a type of follicular puncture, 126 women undergoing in vitro fertilization received either combination clomiphene/hMG or hMG alone according to a randomized test protocol. Within both groups patients for whom a pelvic examination was required had laparoscopies, while others had transvaginal ultrasonically guided punctures as far as possible. Clomiphene/hMG was more efficient than hMG alone as assessed from the cleavage rate (68% vs. 54%; p less than 0.01) and the pregnancy per attempt rate (16% vs. 5%; p less than 0.05). Laparoscopic punctures were more efficient than ultrasonically guided punctures (mean number of recovered oocytes: 4.8 +/- 2.6 vs. 3 +/- 2.5; p less than 0.001), but slightly better results were achieved by this latter method in ongoing pregnancy per puncture rate (18% vs. 8%; NS). With ultrasonically guided punctures, stimulation by clomiphene/hMG allowed better oocyte recoveries (3.8 +/- 2.5 vs. 2.3 +/- 1.9, p less than 0.05). Such results constitute an argument for preferential use of the clomiphene/hMG stimulation protocol with ultrasonically guided punctures. 相似文献
16.
The effects of intracellular Ca2+ (Ca2+i) on K+ currents in hippocampal cells were examined using acutely isolated cells obtained from adult guinea pigs. Whole-cell voltage-clamp recordings were carried out in a configuration that allowed a continuous perfusion of the intracellular medium. Recording media were made to block inward currents and allowed selective activation of K(+)-dependent outward currents. Voltage-dependent outward currents consisted of an initial rapidly decaying component followed by a sustained component. The time constant of decay of the transient current was about 25 msec, and previous studies (Numann et al., 1987) showed that the kinetic and pharmacological properties of this current closely resembled the A current recorded in invertebrate neurons (Connor and Stevens, 1971; Thompson, 1982). Intracellular perfusion of hippocampal cells with a solution containing elevated Ca2+ (about 4.5 x 10(-4) M) elicited outward currents at the holding potential (-45 to -55 mV) and produced changes in voltage-dependent K+ currents. The transient outward current (IA) activated by depolarization was suppressed with increases in Ca2+i. Delayed, sustained K+ currents were greatly potentiated. Data also showed that, among the 3 effects elicited by Ca2+i, suppression of IA was most sensitive to Ca2+i elevation. Previous results (Numann et al., 1987) showed that IA had a lower threshold (about -45 mV) than sustained currents (about -40 mV). By using low levels of depolarization (-40 mV), IA can be selectively activated, and the suppressive effect of Ca2+i on IA was confirmed on the kinetically isolated IA.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
17.
18.
19.
20.
Two samples of kindergarten children's representation and understanding of written number symbols were examined in two time points in one academic year. About 85% of Chinese five year olds (mean = 5 years 10 months) were able to use conventional number symbols to represent the quantity of 30 or larger. At the end of the kindergarten year, 94% of Chinese six year olds (mean = 6 years 4 months) were able to use conventional number symbols to represent the quantity of 100 or larger. Some Chinese six year olds had problems in representing written addition and subtraction tasks. Children's ability to represent written number symbols, ability to represent written addition and subtraction formula and their performance on written addition and subtraction were closely related. The performance of children in a university-affiliated childcare center was better than that of the center serving working-class families in Time 1, but the performance reversed at the end of the kindergarten year. 相似文献