全文获取类型
收费全文 | 3226955篇 |
免费 | 250369篇 |
国内免费 | 7559篇 |
专业分类
耳鼻咽喉 | 45468篇 |
儿科学 | 101496篇 |
妇产科学 | 86693篇 |
基础医学 | 460660篇 |
口腔科学 | 92478篇 |
临床医学 | 303056篇 |
内科学 | 621175篇 |
皮肤病学 | 64950篇 |
神经病学 | 271010篇 |
特种医学 | 125153篇 |
外国民族医学 | 1128篇 |
外科学 | 471940篇 |
综合类 | 76383篇 |
现状与发展 | 2篇 |
一般理论 | 1361篇 |
预防医学 | 269473篇 |
眼科学 | 74988篇 |
药学 | 240857篇 |
10篇 | |
中国医学 | 6506篇 |
肿瘤学 | 170096篇 |
出版年
2018年 | 34771篇 |
2017年 | 26570篇 |
2016年 | 29070篇 |
2015年 | 33096篇 |
2014年 | 47024篇 |
2013年 | 72366篇 |
2012年 | 98226篇 |
2011年 | 103923篇 |
2010年 | 60968篇 |
2009年 | 57624篇 |
2008年 | 97439篇 |
2007年 | 103587篇 |
2006年 | 104434篇 |
2005年 | 101420篇 |
2004年 | 97141篇 |
2003年 | 93421篇 |
2002年 | 91597篇 |
2001年 | 144602篇 |
2000年 | 149458篇 |
1999年 | 126433篇 |
1998年 | 37233篇 |
1997年 | 33786篇 |
1996年 | 33216篇 |
1995年 | 32101篇 |
1994年 | 30138篇 |
1993年 | 28214篇 |
1992年 | 102224篇 |
1991年 | 99306篇 |
1990年 | 96197篇 |
1989年 | 92258篇 |
1988年 | 85730篇 |
1987年 | 84297篇 |
1986年 | 80190篇 |
1985年 | 76630篇 |
1984年 | 58250篇 |
1983年 | 49714篇 |
1982年 | 30261篇 |
1981年 | 26934篇 |
1979年 | 54332篇 |
1978年 | 38435篇 |
1977年 | 32134篇 |
1976年 | 30613篇 |
1975年 | 32085篇 |
1974年 | 39423篇 |
1973年 | 37948篇 |
1972年 | 35356篇 |
1971年 | 32798篇 |
1970年 | 30681篇 |
1969年 | 28388篇 |
1968年 | 26267篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
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
992.
993.
Effects of laundry detergents on Dermatophagoides farinae, Dermatophagoides pteronyssinus, and Euroglyphus maynei. 总被引:2,自引:0,他引:2
DiAnn L Vyszenski-Moher Larry G Arlian Jacquelines S Neal 《Annals of allergy, asthma & immunology》2002,88(6):578-583
BACKGROUND: House-dust mites in clothing and bedding are the source of major allergens. Based on studies of Dermatophagoides pteronyssinus only, weekly washing in hot water is recommended to kill dust mites and remove allergens from clothing and bedding. However, in the United States, washing is most often done in warm or cold water, and other mite species are involved. OBJECTIVE: The purpose of this study was to investigate the lethal effects of various temperatures of hot water alone and hot, warm, and cold water containing detergents and chlorine bleach on Dermatophagoidesfarinae, D. pteronyssinus, and Euroglyphus maynei. METHODS: Mites were soaked in test solutions at various temperatures and for various lengths of time, allowed time to recover, and then analyzed for survival. RESULTS: D. farinae was the most temperature-sensitive and chlorine bleach-sensitive of the three species. In 50 degrees C water alone, 100% mortality for D. farinae was obtained in 10 minutes, whereas most D. pteronyssinus and E. maynei survived. However, 53 degrees C-soaks for 12 and 5 minutes were needed to kill all D. pteronyssinus and E. maynei, respectively. Laundry detergents at their recommended and doubled concentrations and chlorine bleach generally increased mite mortalities over water alone for the three species. Soaking for 4 hours in warm water containing various detergents alone induced mortalities of 19 to 50%, 2 to 35%, and 14 to 46% for D. farinae, D. pteronyssinus, and E. maynei, respectively. CONCLUSIONS: Washing bed linens weekly in warm water with a 4-hour presoak containing most detergents and bleach will kill most D. farinae and, depending on the detergent brand, moderate numbers of D. pteronyssinus. Four-hour soaks in warm water containing the recommended concentrations of various detergents alone also kills moderate numbers of D. farinae, D. pteronyssinus, and E. maynei. Therefore, the cumulative effect of weekly washing with long presoaks should significantly reduce mite levels over time in bed linens, particularly when mattresses and pillows are encased to prevent reinfestation. 相似文献
994.
Peter E Murray Thomas W Smyth Imad About Remeille Remusat Jean-Claude Franquin Anthony J Smith 《Journal of dentistry》2002,30(1):29-36
OBJECTIVES: The incidence of bacterial microleakage, pulp inflammation and necrosis associated with dentine etching treatments prior to restoration are not known. Consequently, to resolve some of the controversy surrounding the effects and importance of vital dentine etching, the authors investigated these factors. METHODS: 110 standardised class V cavities were cut into buccal dentine, without exposing the pulp of teeth scheduled for extraction for orthodontic reasons. Cavities were either left unetched, or etched with the non-equivalent treatments of phosphoric acid gel for 60s or Ethylenediaminetetraacetic acid (EDTA) for 30s, prior to placement of composite resin. Teeth were collected and pulp responses were evaluated according to ISO guidelines, using pathohistomorphometric analysis and ANOVA statistics. RESULTS: Etching was found to be correlated to bacterial microleakage (p=0.0001) and tertiary dentine formation (p=0.0023). Bacterial microleakage was correlated to inflammatory activity (p=0.0001). The frequency of bacterial microleakage was: no etching (65%), EDTA (51%) and phosphoric acid (PA) (20%). SIGNIFICANCE: Vital dentine etching treatment is of extreme importance for the placement of RC to minimise bacterial microleakage. PA etching proved to be more effective at preventing bacterial microleakage than non-etching, and etching with EDTA. 相似文献
995.
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
996.
997.
998.
Kay Kathryn L Roberts Beverley J Turnbull 《The Australian journal of advanced nursing》2002,20(2):8-14
The aim of this study was to document the amount of recent change in Australian nurse academics' scholarly productivity and to investigate the influence of demographic factors such as gender, academic rank, qualifications, increase in qualifications, state of residence, university and university size. Scholarly productivity was calculated from an audit of journal articles. The findings of this study indicate that, while there has been a slight increase in scholarly productivity in the last five years, nursing still lags behind other disciplines. Scholarly productivity was found to be positively associated with highest academic qualification, academic rank and promotion. The study indicates the continuing need for senior nurse academics to provide mentoring to colleagues and foster the development of skills associated with scholarly productivity. 相似文献
999.
A prospective, randomized controlled study of computer-assisted learning in parasitology. 总被引:1,自引:0,他引:1
PURPOSE: To compare, using a prospective, randomized controlled study, three methods of teaching a medical school parasitology course: computer-based instruction, traditional lecture-based instruction, and a combination of computer-based and lecture-based instruction. METHOD: A single class of the University of Utah School of Medicine was randomized into three study groups for the second-year parasitology course. The computer group (n = 29) used a locally developed interactive parasitology computer program; the lecture group (n = 32) had traditional lectures, and the combined group (n = 33) used both the computer program and lectures. Students' knowledge was assessed using a pretest, a final examination, and a posttest administered four months after the course. Students also used logs to track the amounts of time they spent studying. Their impressions and course evaluations were collected using a standardized course-evaluation form. RESULTS: The groups' scores on the pretest, final examination, and posttest were not statistically significantly different. Students in the computer group averaged 26.8 hours of studying over the two-week course compared with 32.1 hours in the lecture group and 32.7 hours in the combined group. The difference in study times between the computer and combined groups yielded a significant p value of 0.036. Students were generally positive about the course and the computer program. CONCLUSION: Students can learn parasitology from computer-based instruction as effectively as from traditional lecture-based instruction, and they can do so in less time. 相似文献
1000.
D J Bowen 《Journal of clinical pathology》2002,55(1):1-18
This review focuses on selected areas that should interest both the scientist and the clinician alike: polymorphisms within the factor VIII and factor IX genes, their linkage, and their ethnic variation; a general assessment of mutations within both genes and a detailed inspection of the molecular pathology of certain mutations to illustrate the diverse cause–effect relations that exist; a summary of current knowledge on molecular aspects of inhibitor production; and an introduction to the new areas of factor VIII and factor IX catabolism. An appendix defining various terms encountered in the molecular genetics of the haemophilias is included, together with an appendix providing accession numbers and locus identification links for accessing gene and sequence information in the international nucleic acid databases. 相似文献