全文获取类型
收费全文 | 3267篇 |
免费 | 226篇 |
国内免费 | 45篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 120篇 |
妇产科学 | 193篇 |
基础医学 | 398篇 |
口腔科学 | 78篇 |
临床医学 | 336篇 |
内科学 | 543篇 |
皮肤病学 | 42篇 |
神经病学 | 363篇 |
特种医学 | 260篇 |
外科学 | 314篇 |
综合类 | 38篇 |
一般理论 | 4篇 |
预防医学 | 329篇 |
眼科学 | 28篇 |
药学 | 254篇 |
中国医学 | 2篇 |
肿瘤学 | 218篇 |
出版年
2021年 | 41篇 |
2020年 | 33篇 |
2019年 | 58篇 |
2018年 | 50篇 |
2017年 | 38篇 |
2016年 | 28篇 |
2015年 | 53篇 |
2014年 | 66篇 |
2013年 | 93篇 |
2012年 | 139篇 |
2011年 | 115篇 |
2010年 | 81篇 |
2009年 | 67篇 |
2008年 | 105篇 |
2007年 | 148篇 |
2006年 | 103篇 |
2005年 | 118篇 |
2004年 | 94篇 |
2003年 | 91篇 |
2002年 | 88篇 |
2001年 | 117篇 |
2000年 | 111篇 |
1999年 | 100篇 |
1998年 | 57篇 |
1997年 | 40篇 |
1996年 | 44篇 |
1994年 | 38篇 |
1993年 | 39篇 |
1992年 | 75篇 |
1991年 | 74篇 |
1990年 | 62篇 |
1989年 | 82篇 |
1988年 | 67篇 |
1987年 | 75篇 |
1986年 | 85篇 |
1985年 | 94篇 |
1984年 | 69篇 |
1983年 | 54篇 |
1982年 | 31篇 |
1981年 | 29篇 |
1980年 | 34篇 |
1979年 | 43篇 |
1978年 | 40篇 |
1977年 | 40篇 |
1976年 | 42篇 |
1975年 | 39篇 |
1973年 | 30篇 |
1972年 | 32篇 |
1971年 | 24篇 |
1969年 | 26篇 |
排序方式: 共有3538条查询结果,搜索用时 31 毫秒
61.
U G P?hls S P Renner P A Fasching M P Lux H Kreis S Ackermann H-G Bender M W Beckmann 《European journal of cancer prevention》2004,13(4):249-256
The efficacy of early breast cancer detection programmes seems to be mainly influenced by the awareness of breast cancer in general among healthy women. This study aimed to provide information about women's understanding of breast cancer incidence and risk of disease. Based on a newly developed questionnaire 2108 healthy women were asked about their knowledge and perceptions in relation to breast cancer incidence, risk factors, risk perception and level of concern. Of these women 78.8% were well aware of breast cancer in general terms. However, there were major aspects such as incidence or risk factors that were poorly understood. Only one-third correctly estimated the incidence of breast cancer; 95% understood breast cancer in the familial history as a risk factor, but only 57% understood the age risk; 37.1% of women perceived hormonal contraceptives and 35.9% hormonal replacement therapy as risk factors of breast cancer. The latter estimation was significantly higher in women above 40 years. Recommendations for the improvement of cancer prevention programmes include targeting understanding of lifetime risk of breast cancer, age as a risk factor, survival from breast cancer or hormonal factors. There is a need to separately address the perceptions of women depending on age, social status and educational levels. 相似文献
62.
As the quality of water in dialysis fluid varies considerably, dialysate is often contaminated by large amounts of bacteria and endotoxins. Membrane properties and operating pressures are acknowledged to give high-flux dialysis with bicarbonate the bacteriological potential to favor passage of endotoxin fragments from the dialysate into the blood stream. Therefore, a sterile dialysate will have to become a standard. Ultrafiltration across hydrophobic synthetic membranes was shown to remove endotoxins (and their fragments) from dialysis water by the combined effect of filtration and adsorption. However, each module can be used for a limited time only. Ceramic membranes may represent an alternative to polymeric membranes for endotoxin removal. In this article, we tested the capacity of different commercial ceramic membranes with nominal molecular weight cut-off down to 1,000 to retain endotoxins from Ps. aeruginosa. The tested membranes did not generally produce dialysate meeting the Association for the Advancement of Medical Instrumentation standard. When using aluminum-containing membranes, we detected aluminum leaking into the dialysate that could possibly be transported into the blood stream. 相似文献
63.
BACKGROUND: The aim of this study is to describe the technique and results of the endovascular approach through the thrombosed inferior petrosal sinus (IPS) for occlusion of dural cavernous sinus fistulas (DCSFs). METHODS: In four patients presenting with clinically symptomatic DCSFs, the angiogram did not show opacification of the IPS, indicating that it neither drained the arteriovenous fistula nor the cerebral venous outflow. A large volume biplane phlebogram of the jugular bulb was obtained to identify a thrombosed remnant of the IPS. We were able to navigate small hydrophilic catheters and microguide wires through the thrombosed IPS into the ipsi- or contralateral CS. After reaching the fistula site the CS was packed with detachable platinum coils. RESULTS: We were able to reach the fistula site and to achieve a dense packing of coils within the arteriovenous shunting zone in all of the patients. The final angiogram showed subtotal or complete occlusion of the arteriovenous fistula. All four patients recovered completely and showed disappearance of the fistula on follow-up arteriograms. One patient developed a transient sixth nerve palsy. No complications related to the approach were observed. CONCLUSIONS: For endovascular treatment, transvenous occlusion of DCSFs via the IPS is a feasible approach, even when this sinus is partially or completely thrombosed. Gentle handling of recently available, improved hydrophilic microguide wires and microcatheters allows effective and safe catheter navigation into the CS. A phlebogram of the jugular bulb is very useful for identification of a thrombosed IPS. 相似文献
64.
Status of nutrition labeling, health claims, and nutrient content claims for processed foods: 1997 Food Label and Package Survey 总被引:2,自引:0,他引:2
Brecher SJ Bender MM Wilkening VL McCabe NM Anderson EM 《Journal of the American Dietetic Association》2000,100(9):1057-1062
The Food and Drug Administration (FDA) conducts studies of food labels as part of its ongoing monitoring of the nutritional status of the US population. In 1994 FDA nutrition labeling rules were implemented and in 1997 the Food Label and Package Survey characterized various aspects of the labeling of processed, packaged foods, including nutrition labeling, health claims, and nutrient content claims. For the survey, FDA selected a multistage, representative sample of food products from the SCAN-TRACK food sales database (AC Nielsen Co, Schaumburg, Ill). FDA identified 58 product groups and selected those product classes from the database that accounted for 80% of sales in each group. From each product class, FDA selected the 3 top-selling product brands and randomly selected follower brands. Based on label information from a final sample of 1,267 food products, FDA determined the percentage of products sold that bear Nutrition Facts labels, health claims, and nutrient content claims. The purpose of this article was to present FDA findings regarding the status of food labels 3 years after implementation of the nutrition labeling rules. Nutrition-labeled products accounted for an estimated 96.5% of the annual sales of processed, packaged foods. An additional 3.4% of products sold were exempt from labeling regulations. Nutrient content claims and health claims appeared on an estimated 39% and 4%, respectively, of the products sold. Dietitians and other health care professionals can use this survey information to identify food types with specific label information and to assist the US consumer in making more varied and healthful food choices in the marketplace. 相似文献
65.
CT of focal nodular hyperplasia of the liver 总被引:36,自引:0,他引:36
Carlson SK Johnson CD Bender CE Welch TJ 《AJR. American journal of roentgenology》2000,174(3):705-712
66.
Michael Patrick Lux Sven Ackermann Mayada R Bani Caroline Nestle-Kr?mling Timm O Goecke Dieter Niederacher R Bodden-Heidrich Hans-Georg Bender Matthias Wilhelm Beckmann Peter Andreas Fasching 《European journal of cancer prevention》2005,14(6):503-511
INTRODUCTION: Some 5-10% of all cases of breast cancer and ovarian cancer have a hereditary genesis. In the setting of an interdisciplinary cancer genetics clinic, a study of the age at which patients first take advantage of early cancer detection (ECD) facilities was conducted in order to assess the influence of familial risk on health issues. METHODS: The study included 556 women who fulfilled the inclusion criteria (IC) for genetic analysis of the BRCA1 and BRCA2 genes, as well as 205 who did not meet these criteria but attended the primary consultation. RESULTS: Consulters who met the inclusion criteria took advantage of nearly all methods of ECD at an earlier time than women who did not. A comparison of consulters with or without breast cancer showed that those without breast cancer participated in all methods of ECD at an earlier time. CONCLUSION: Methods of improving and increasing participation in ECD facilities, and of encouraging women who are at risk to start on such programs at a younger age, need to be discussed. In this study, familial risk already resulted in a younger age of uptake of ECD facilities. 相似文献
67.
This study examined a comprehensive screening model within children attending Head Start programs from urban (n =232) and rural (n = 231) communities. The Devereux Early Childhood Assessment (DECA; LeBuffe & Naglieri, 1999 ) was used to measure social‐emotional protective factors (i.e., Total Protective Factors [TPF]) and risk factors (i.e., Behavior Concerns [BC]) within children that resided in two different community settings. Children from low‐income rural programs received higher scores on a subscale measuring children's relationship to adults (i.e., Attachment subscale). Additionally, children from low‐income urban programs received higher scores on children's ability to self‐regulate (i.e., Self‐Control subscale). Significant differences between children from rural and urban settings were not found on the primary scales (BC or TPF) of the DECA. Statistically significant gender differences by community‐type were not found. Findings contribute to the literature by illustrating that community characteristics might influence the development of different social‐emotional behaviors in preschool children. © 2011 Wiley Periodicals, Inc. 相似文献
68.
Eugen Dhimolea Ricardo de Matos Simoes Dhvanir Kansara Aziz Al’Khafaji Juliette Bouyssou Xiang Weng Shruti Sharma Joseline Raja Pallavi Awate Ryosuke Shirasaki Huihui Tang Brian J. Glassner Zhiyi Liu Dong Gao Jordan Bryan Samantha Bender Jennifer Roth Michal Scheffer Constantine S. Mitsiades 《Cancer cell》2021,39(2):240-256.e11
- Download : Download high-res image (202KB)
- Download : Download full-size image
69.
70.
Recently, Laubender and Bender (Stat. Med. 2010; 29: 851–859) applied the average risk difference (RD) approach to estimate adjusted RD and corresponding number needed to treat measures in the Cox proportional hazards model. We calculated standard errors and confidence intervals by using bootstrap techniques. In this paper, we develop asymptotic variance estimates of the adjusted RD measures and corresponding asymptotic confidence intervals within the counting process theory and evaluated them in a simulation study. We illustrate the use of the asymptotic confidence intervals by means of data of the Düsseldorf Obesity Mortality Study. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献