全文获取类型
收费全文 | 1024984篇 |
免费 | 65584篇 |
国内免费 | 2603篇 |
专业分类
耳鼻咽喉 | 14057篇 |
儿科学 | 31868篇 |
妇产科学 | 28998篇 |
基础医学 | 141883篇 |
口腔科学 | 27195篇 |
临床医学 | 86914篇 |
内科学 | 208553篇 |
皮肤病学 | 20339篇 |
神经病学 | 81730篇 |
特种医学 | 40349篇 |
外国民族医学 | 348篇 |
外科学 | 160186篇 |
综合类 | 20973篇 |
现状与发展 | 1篇 |
一般理论 | 336篇 |
预防医学 | 75228篇 |
眼科学 | 23252篇 |
药学 | 71641篇 |
20篇 | |
中国医学 | 1952篇 |
肿瘤学 | 57348篇 |
出版年
2019年 | 8472篇 |
2018年 | 11237篇 |
2017年 | 8852篇 |
2016年 | 9522篇 |
2015年 | 10746篇 |
2014年 | 15420篇 |
2013年 | 24079篇 |
2012年 | 32543篇 |
2011年 | 34369篇 |
2010年 | 20553篇 |
2009年 | 19426篇 |
2008年 | 32819篇 |
2007年 | 35153篇 |
2006年 | 34980篇 |
2005年 | 34516篇 |
2004年 | 33180篇 |
2003年 | 32028篇 |
2002年 | 31528篇 |
2001年 | 42987篇 |
2000年 | 44001篇 |
1999年 | 37765篇 |
1998年 | 11411篇 |
1997年 | 10442篇 |
1996年 | 10207篇 |
1995年 | 9551篇 |
1994年 | 9069篇 |
1993年 | 8471篇 |
1992年 | 29458篇 |
1991年 | 28193篇 |
1990年 | 27492篇 |
1989年 | 26397篇 |
1988年 | 24510篇 |
1987年 | 24146篇 |
1986年 | 23205篇 |
1985年 | 22147篇 |
1984年 | 16884篇 |
1983年 | 14513篇 |
1982年 | 9202篇 |
1981年 | 8091篇 |
1979年 | 15447篇 |
1978年 | 10961篇 |
1977年 | 9380篇 |
1976年 | 8804篇 |
1975年 | 9611篇 |
1974年 | 11313篇 |
1973年 | 10736篇 |
1972年 | 10125篇 |
1971年 | 9284篇 |
1970年 | 8929篇 |
1969年 | 8302篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
M A Ignelzi H W Fields R P White G Bergenholtz F A Booth 《Oral surgery, oral medicine, and oral pathology》1990,70(2):214-220
A panoramic radiograph obtained during orthodontic treatment revealed an intracoronal radiolucency within an unerupted permanent second molar. This unusual entity was successfully treated by surgical and endodontic intervention, followed by restorative and orthodontic treatment. These treatments enabled the tooth to maintain pulpal vitality, erupt, complete root formation, and function. This report will review the proposed etiologies for this condition, discuss the need for surgical intervention, and present the details of the case. 相似文献
102.
The Authors present the results of a clinical study concerning 30 IDDM patients and 24 healthy subjects to evaluate periodontal disease. The results show a higher incidence of PI, PD and BTI in diabetic patients. 相似文献
103.
Microleakage of seven temporary restorative materials was evaluated in endodontic access preparations made in teeth restored with amalgam. Ten teeth were used for each of the seven materials: Cavit, Cavit-G, TERM, zinc phosphate cement, polycarboxylate cement, glass ionomer cement, and IRM. A class I amalgam was placed in the occlusal surface of each experimental tooth and an endodontic access preparation was made entirely within the amalgam. Then the access preparation was restored with one of the temporary restorative materials, and microleakage was evaluated using a fluid filtration technique. The amount of microleakage was quantitated by measuring the fluid flow at 15 min, 1 h, 24 h, 1 wk, and 2 wk after insertion of the temporary restoration. Cavit, Cavit-G, TERM, IRM, and glass ionomer cement all provided excellent seals while zinc phosphate cement and polycarboxylate cement provided less effective seals. 相似文献
104.
The presence of bacteria in periapical lesions of teeth with necrotic pulp has been demonstrated by microbiological sampling of periapical lesions during endodontic surgery. The purpose of this study was to confirm the presence of Bacteroides intermedius in a periapical granuloma using an indirect immunofluorescence technique. Histologic sections of a periapical granuloma were incubated with a rabbit antiserum to B. intermedius. After incubation with secondary antibody (fluorescein-conjugated goat anti-rabbit IgG), an intense fluorescent staining was observed in areas of the tissue sections. Control tissue sections that were incubated without the antibody remained unstained. The results obtained with the indirect immunofluorescence technique supported our cultural findings that microorganisms, e.g. B. intermedius, were present in the tissue of the periapical granuloma. 相似文献
105.
Electrotherapy and hyperbaric oxygen: promising treatments for postradiation complications 总被引:2,自引:0,他引:2
Electrotherapy and hyperbaric oxygen therapy have been added to physical therapy to treat patients with postsurgery and radiation sequelae. Problems of reduced oral opening and range of head movement, soft tissue necrosis, osteoradionecrosis, and delayed wound healing were addressed in 37 patients over a 3-year period. Of this group, 16 irradiated maxillary resection patients were specifically followed up to determine the effectiveness of the new modalities on improving reduced oral opening. Although healing and the quality of the soft tissues showed marked improvement there was no significant improvement in oral opening. 相似文献
106.
Toothbrushing force in relation to plaque removal 总被引:1,自引:0,他引:1
G. A. van der Weijden M. F. Timmerman E. Reijerse C. M. Snoek U. van der Velden 《Journal of clinical periodontology》1996,23(8):724-729
Abstract This was a 2-part study. The purpose of the 1st part was to examine the relationship between brushing force and plaque removal efficacy comparing a regular manual toothbrush (M) with an electric toothbrush the Braun Oral-B Plak Control* (B). The study consisted of a single oral prophylaxis followed by 5 experiments which differed solely in respect to toothbrushing force. At baseline (after 24-h plaque accumulation), the amount of dental plaque was evaluated and subsequently, the subject's mouth was brushed by a dental hygienist. Brushing was carried out in a random split-mouth order. Either the 1st and 3rd quadrants or the 2nd and 4th quadrants were brushed with 1 toothbrush and the 2 remaining quadrants with the other. The available time for the brushing procedure was 2 min. After brushing, the amount of remaining dental plaque was assessed. The force used in experiment 1 through 5 was 100, 150, 200, 250, 300 g, respectively. The results show that when brushing force is increased, more plaque is removed with either of the two brushes. Except for the high brushing force (300 g), the electric toothbrush removed more plaque than the manual brush. The purpose of the 2nd part was to evaluate the habitual brushing force which individuals use with various toothbrushes. Besides a manual toothbrush (M), 3 electric toothbrushes were examined, the Rotadent® (R). Interplak® (I) and Braun® (B). 20 subjects were selected on the basis of being ‘good brushers” (plaque score at screening <25%). At baseline, each subject randomly received 1 of the 4 brushes. They were allowed a training period of 3 weeks at the end of which they were asked to abstain from brushing for at least 24 h. The plaque (Turesky modification of the Quigley & Hein) was scored, after which the subjects brushed their teeth (2 min) with the assigned toothbrush equipped with a strain gauge. A computer set–up measured (100 Hz) and calculated the mean brushing force. After brushing, the amount of remaining plaque was assessed. The design of the study was a 4-way cross-over. The results show that with a manual brush, considerably more force is used than with the electric brushes (R=96. 1 = 119. B= 146, M=273). No significant relation between brushing force and plaque removal was demonstrated for any of the brushes. 相似文献
107.
M.C.P.M. da Cunha M. Weber F.C. Nart 《Journal of electroanalytical chemistry (Lausanne, Switzerland)》1996,414(2):163-170
The adsorption of nitrate ions on gold and platinum electrodes in acid solution has been studied in acidic solution using in situ FURS. It is found that nitrate is adsorbed probably with a two-fold coordination on gold electrodes as suggested by the adsórbate potential-dependent spectral feature centered between 1440 and 1460 cm?1. In addition, partial reduction of the nitrate ions at more negative potentials (ca. 0.05 V) generates nitrite ions in solution. These ions are co-adsorbed with nitrate ions in the double layer region of potentials. The nitrite ions seem to be adsorbed O-down with a one-fold or two-fold coordination. Platinum electrodes are found to be much more active catalytically to nitrate reduction than gold electrodes. The reduction of nitrate ions at potentials below 0.8 V generates an adsorbed product presenting a potential-dependent band at 1540 to 1580 cm?1 which has been identified as adsorbed NO. 相似文献
108.
Although a wide range of bacterial species has been isolated from infected dental root canals it remains necessary to determine whether any particular group of such bacteria is associated with specific endodontic symptoms and clinical signs. In this study 30 root canals were examined microbiologically; of these, 14 were associated with pain, 20 with tenderness to percussion, 23 presented with wet root canals, seven with swelling, five with purulent exudate and four with a sinus. Clinical and microbiological correlation was observed particularly with regard to pain where anaerobes were isolated from 93% of painful canals and only from 53% of painfree canals. The former yielded means of 2.5 anaerobic species and 1.6 facultative species per canal, compared with 1.5 and 2.4 in painfree canals. Prevotella spp. were isolated from 64.2% of painful canals and 12.5% of painless canals (P<0.01) similarly, peptostreptococci were isolated from 71.4% of painful and 31.3% of painless canals (P<0.05). It was concluded that a significant association exists between pain and the presence of Prevotella and Peptostreptococcus spp. in dental root canals. 相似文献
109.
F G Oppenheim D I Hay D J Smith G D Offner R F Troxler 《Journal of dental research》1987,66(2):462-466
Acidic proline-rich phosphoproteins and phosphopeptides are abundant components of parotid and submandibular salivary secretions in man and in the subhuman primate, Macaca fascicularis. The major acidic proline-rich proteins and the proline-rich phosphopeptide, statherin, of man and macaques have been shown to be potent inhibitors of calcium phosphate precipitation and are thought to function in the oral environment by maintaining saliva supersaturated with respect to calcium phosphate salts. Little is known about the biosynthesis of these proline-rich phosphoproteins and peptides, and the aim of the present work was to determine the structural relationship between statherin precursors and native human and macaque statherin. RNA was isolated from human submandibular gland, and poly(A+) mRNA was selected by affinity chromatography on oligo(dT) cellulose and translated in a reticulocyte lysate. Electrophoretic analysis of the translation products revealed that this mRNA directed the synthesis of a large number of polypeptides with Mrs ranging from 5000 to 70,000. Immunoprecipitates, prepared with an antiserum directed against human statherin, contained a single component with a Mr of 7800, approximately 2000 daltons larger than native statherin. Radiosequencing of the in vitro precursor of statherin in immunoprecipitates demonstrated the presence of a 19-residue signal peptide. These results suggest that statherin is derived from a unique structural gene, and does not result from proteolytic processing of a large polyprotein precursor. 相似文献
110.