全文获取类型
收费全文 | 976674篇 |
免费 | 67239篇 |
国内免费 | 3034篇 |
专业分类
耳鼻咽喉 | 13377篇 |
儿科学 | 31014篇 |
妇产科学 | 28011篇 |
基础医学 | 137039篇 |
口腔科学 | 26492篇 |
临床医学 | 81165篇 |
内科学 | 199654篇 |
皮肤病学 | 20626篇 |
神经病学 | 78747篇 |
特种医学 | 39398篇 |
外国民族医学 | 355篇 |
外科学 | 152680篇 |
综合类 | 20609篇 |
一般理论 | 291篇 |
预防医学 | 69196篇 |
眼科学 | 21362篇 |
药学 | 70082篇 |
3篇 | |
中国医学 | 2263篇 |
肿瘤学 | 54583篇 |
出版年
2019年 | 7770篇 |
2018年 | 10719篇 |
2017年 | 8462篇 |
2016年 | 9087篇 |
2015年 | 10362篇 |
2014年 | 14499篇 |
2013年 | 22251篇 |
2012年 | 29700篇 |
2011年 | 31519篇 |
2010年 | 19342篇 |
2009年 | 18217篇 |
2008年 | 29862篇 |
2007年 | 31561篇 |
2006年 | 31576篇 |
2005年 | 30955篇 |
2004年 | 30093篇 |
2003年 | 29208篇 |
2002年 | 28786篇 |
2001年 | 44017篇 |
2000年 | 45192篇 |
1999年 | 38386篇 |
1998年 | 10878篇 |
1997年 | 9861篇 |
1996年 | 9722篇 |
1995年 | 9054篇 |
1994年 | 8617篇 |
1993年 | 8111篇 |
1992年 | 29488篇 |
1991年 | 28221篇 |
1990年 | 27488篇 |
1989年 | 26386篇 |
1988年 | 24517篇 |
1987年 | 24022篇 |
1986年 | 23096篇 |
1985年 | 21929篇 |
1984年 | 16397篇 |
1983年 | 14029篇 |
1982年 | 8433篇 |
1979年 | 15031篇 |
1978年 | 10539篇 |
1977年 | 8924篇 |
1976年 | 8401篇 |
1975年 | 9284篇 |
1974年 | 11091篇 |
1973年 | 10560篇 |
1972年 | 10011篇 |
1971年 | 9238篇 |
1970年 | 8871篇 |
1969年 | 8304篇 |
1968年 | 7958篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
F M Barker 《Journal of the American Optometric Association》1988,59(7):558-560
Since its introduction in early 1985, the Volk +90D lens has become a very popular auxiliary lens for biomicroscopic fundus evaluation. The Volk +90D lens provides a wide field of view which is accessible by simple scanning of the biomicroscope. The necessity to hand hold the lens, however, has not always provided enough stability, particularly for the novice user. This article describes a newly introduced holder for the Volk +90D lens which mounts on the base of the biomicroscope headrest providing rapid and stable lens placement. Use of this holder improves the technique of retinal examination and photography by stabilizing the image and by freeing both hands to operate the slit lamp biomicroscope. The enhanced stability afforded by this holder also gives the examiner the practical capability of viewing the posterior pole without mydriasis. 相似文献
102.
The response of single detergent treated bovine retinal pigment epithelial cells in culture to ATP was measured with an image analyser. The most pronounced contraction was produced by 1.0 mM ATP with most change taking place in the first 10 min. At 1 h the area had decreased by about 33%, perimeter 22% and maximum length 25%. By way of comparison rabbit skin fibroblasts had a decreased area of approximately 40%, perimeter 25% and maximum length 22%. Bovine aortic smooth muscle cells on the other hand decreased in area by 55%, perimeter 40% and maximum length 36%. It is hoped that this assay may be used to evaluate drugs which could counteract contractile events in proliferative vitreoretinopathy. 相似文献
103.
Tear mucus crystallization in children with cystic fibrosis 总被引:1,自引:0,他引:1
M Rolando F Baldi G Calabria 《Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift für Augenheilkunde》1988,197(4):202-206
Cystic fibrosis is characterized by an abnormally high electrolyte concentration in exocrine secretions. The authors performed the tear mucus ferning test in 26 eyes of children with cystic fibrosis and compared the results to those in an equal number of age-matched normals. The results suggest that the increased electrolyte concentration could be responsible for the increased hyperviscosity of mucus. The tear mucus ferning test appears to be a suitable diagnostic test for the assessment of cystic fibrosis. 相似文献
104.
105.
106.
Acta Endoscopica - L’hémorragie iatrogène en endoscopie digestive reste pour l’essentiel l’apanage des techniques de résection tumorale et de la... 相似文献
107.
M. Wensing A. H. Penninks† S. L. Hefle‡ J. H. Akkerdaas§ R. van Ree§ S. J. Koppelman† C. A. F. M. Bruijnzeel-Koomen A. C. Knulst 《Clinical and experimental allergy》2002,32(12):1757-1762
BACKGROUND: The risk for allergic reactions depends on the sensitivity of individuals and the quantities of offending food ingested. The sensitivity varies among allergic individuals, as does the threshold dose of a food allergen capable of inducing an allergic reaction. OBJECTIVE: This study aimed at determining the distribution of minimum provoking doses of hazelnut in a hazelnut-allergic population. METHODS: Thirty-one patients with a history of hazelnut-related allergic symptoms, a positive skin prick test to hazelnut and/or an elevated specific IgE level, were included. Double-blind, placebo-controlled food challenges (DBPCFC) were performed with seven increasing doses of dried hazelnut (1 mg to 1 g hazelnut protein) randomly interspersed with seven placebo doses. RESULTS: Twenty-nine patients had a positive challenge. Itching of the oral cavity and/or lips was the first symptom in all cases. Additional gastrointestinal symptoms were reported in five patients and difficulty in swallowing in one patient. Lip swelling was observed in two patients, followed by generalized urticaria in one of these. Threshold doses for eliciting subjective reactions varied from a dose of 1 mg up to 100 mg hazelnut protein (equivalent to 6.4-640 mg hazelnut meal). Extrapolation of the dose-response curve showed that 50% of our hazelnut-allergic population will suffer from an allergic reaction after ingestion of 6 mg (95% CI, 2-11 mg) of hazelnut protein. Objective symptoms were observed in two patients after 1 and 1,000 mg, respectively. CONCLUSION: DBPCFCs demonstrated threshold doses in half of the hazelnut-allergic patients similar to doses previously described to be hidden in consumer products. This stresses the need for careful labelling and strategies to prevent and detect contamination of food products with hazelnut residues. 相似文献
108.
D. Lothschütz M. Jennewein S. Pahl H.F. Lausberg A. Eichler W. Mutschler R.G. Hanselmann M. Oberringer 《Inflammation research》2002,51(8):416-422
OBJECTIVE AND DESIGN: Inflammatory and tumorous bronchi were screened in order to obtain new tumor relevant cytogenetic parameters. MATERIAL OR SUBJECTS: Bronchial cells of 32 patients were cultivated by standard cell culture procedures. METHODS: Tetraploidy and aneuploidy was determined by enumeration of chromosome 7 and 8 versus the number of centrosomes. The resulting data were correlated with histopathological data. RESULTS: Tetra- and aneuploidy of epithelial cells were detectable in 76% of tumor cell cultures, 75% of high grade inflammatory tissues and 40% of non- and low grade-inflammatory tissues. Additionally, we observed centrosome hyper-amplification and multipolar mitoses not only in the tumor but also in the early stages of inflammation. CONCLUSION: Inflammatory bronchi already show tumor-specific features and may consequently represent the preliminary genetic stage of cancer development in bronchi. 相似文献
109.
T. Berghmans F. Crokaert J. Sculier 《European journal of clinical microbiology & infectious diseases》2002,21(9):676-678
Vibrio cholerae was isolated from the blood cultures of a neutropenic patient treated with chemotherapy for non-small-cell lung cancer. Attempts
to isolate Vibrio spp. from a rectal swab and stool were unsuccessful. Piperacillin/tazobactam treatment resulted in eradication of the microorganism
from the patient's blood. Although Vibrio spp. have occasionally been the source of infection in immunocompromised patients, this report describes the first case of
non-0:1 Vibrio cholerae bacteremia in a neutropenic patient with a solid tumour.
Electronic Publication 相似文献
110.
A. Giacometti O. Cirioni G. Greganti A. Fineo R. Ghiselli M. Del Prete F. Mocchegiani B. Fileni F. Caselli E. Petrelli V. Saba G. Scalise 《European journal of clinical microbiology & infectious diseases》2002,21(7):553-556
The in vitro activities of povidone iodine, potassium peroxymonosulfate, and dimethyldidecylammonium chloride were investigated
against 379 nosocomial isolates of Staphylococcus aureus and Pseudomonas aeruginosa responsible for surgical wound infections in patients operated on between July 1995 and June 2001. Overall, the isolates
were inhibited by the antiseptics at concentrations below those used routinely. In spite of increasing resistance to the various
antibiotics used to treat surgical wound infections, no significant variation in the susceptibility to antiseptics was demonstrated
during this 6-year study.
Electronic Publication 相似文献