全文获取类型
收费全文 | 2748篇 |
免费 | 204篇 |
国内免费 | 1篇 |
出版年
2023年 | 24篇 |
2022年 | 16篇 |
2021年 | 61篇 |
2020年 | 56篇 |
2019年 | 74篇 |
2018年 | 113篇 |
2017年 | 90篇 |
2016年 | 117篇 |
2015年 | 142篇 |
2014年 | 140篇 |
2013年 | 193篇 |
2012年 | 228篇 |
2011年 | 218篇 |
2010年 | 148篇 |
2009年 | 103篇 |
2008年 | 153篇 |
2007年 | 156篇 |
2006年 | 157篇 |
2005年 | 116篇 |
2004年 | 100篇 |
2003年 | 99篇 |
2002年 | 82篇 |
2001年 | 50篇 |
2000年 | 19篇 |
1999年 | 20篇 |
1998年 | 16篇 |
1997年 | 11篇 |
1996年 | 12篇 |
1995年 | 13篇 |
1994年 | 17篇 |
1993年 | 12篇 |
1992年 | 7篇 |
1991年 | 13篇 |
1990年 | 9篇 |
1989年 | 11篇 |
1988年 | 15篇 |
1986年 | 7篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1979年 | 9篇 |
1976年 | 6篇 |
1975年 | 8篇 |
1974年 | 6篇 |
1972年 | 6篇 |
1971年 | 8篇 |
1970年 | 6篇 |
1969年 | 6篇 |
1968年 | 6篇 |
排序方式: 共有2953条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
Josef Stingl Petr Zach Josef Sach Jana Vranova Zdenek Suchomel Vaclav Kudrna Jana Mrzilkova David Kachlik Vladimir Musil 《Journal of morphology》2020,281(11):1476-1485
The aim of this study was to perform a pilot histological and quantitative analysis of the blood vessels accompanying the epicardial nerves (vasa nervorum) in the porcine hearts. Twenty healthy porcine hearts were used in this study. The blood vessels were analyzed by light microscopy using four different staining techniques in transverse sections taken from the upper, middle, and lower segments of the anterior part of the interventricular region and the adjacent parts of the right and left ventricles containing epicardial nerves and the endocardial peripheral parts of the Purkinje fibers. In total, 317 epicardial nerves were detected. The vasa nervorum were present in 75.7% of these nerves. The vasa nervorum resembled arterioles and postcapillary and collecting venules. One hundred and forty nine epicardial nerves were perivascular, located in the adventitia of the anterior interventricular artery and vein. The remaining 168 nerves ran freely through the epicardial interstitium. The presence of the vasa nervorum was not related to topographical location or nerve diameter. Additionally, from a total of 33 analyzed ventricular complexes of Purkinje fibers small blood vessels located in their proximity were identified in only two cases. It can be concluded that the majority of the anterior epicardial nerves of porcine heart possess well-developed vasa nervorum. In contrast, similar blood vessels are rarely present in the vicinity of the Purkinje fibers. The data obtained contribute to a better understanding of the nutrition of the cardiac nerves. 相似文献
15.
The degradation and fermentation of microcrystalline cellulose were studied in monoculture of the polycentric anaerobic fungus Orpinomyces joyonii and in co-cultures with the rumen bacteria Megasphaera elsdenii and Eubacterium limosum. More than 25% of cellulose hydrolysis products (glucose and cellodextrins) were released by the fungus into the medium after 8 d of cultivation. These products were metabolized by bacteria in mixed cultures. In co-culture with the fungus M. elsdenii and E. limosum . increased the extent of microcrystalline cellulose degradation by 10·12% and 7·96%, respectively. Biomass yield in co-cultures was increased by 89·9% and 59·4% for M. elsdenii and E. limosum . Ycellulose for fungus alone was 52·29 g dry matter mol-1 glucose. These values were 64·93 and 55·92 g mol-1 glucose unit in co-culture with M. elsdenii and E. limosum , respectively. 相似文献
16.
Jiri Moos Petr Kalab Gregory S. Kopf Richard M. Schultz 《Molecular reproduction and development》1994,38(1):91-93
A rapid, nonradioactive method to monitor the ZP2 to ZP2f conversion in the zona pellucida of single mouse eggs has been developed. This assay is based on the chemiluminescent detection of biotinylated ZP2 and ZP2f following electrophoresis under reducing conditions and electrophoretic transfer to Immobilon P. This method is about 10 times faster and detects similar extents of ZP2 to ZP2f conversion following A23187-induced egg activation, when compared to the commonly used radioiodination procedures. © 1994 Wiley-Liss, Inc. 相似文献
17.
18.
Biomechanics and Modeling in Mechanobiology - Digital models based on finite element (FE) analysis are widely used in orthopaedics to predict the stress or strain in the bone due to... 相似文献
19.
20.
Ales Tichopad Craig Roberts Igor Gembula Petr Hajek Anna Skoczynska Waleria Hryniewicz Karina Jahnz-Rozyk Roman Prymula Ivan Solovi? Vitězslav Kolek 《PloS one》2013,8(8)
We estimate and describe the incidence rates, mortality, and cost of CAP (community-acquired pneumonia), in both inpatient and outpatient settings, in the Czech Republic (CZ), Slovakia (SK), Poland (PL), and Hungary (HU). A retrospective analysis was conducted on administrative data from the health ministry and insurance reimbursement claims with a primary diagnosis of pneumonia in 2009 to determine hospitalization rates, costs, and mortality in adults ≥50 years of age. Patient chart reviews were conducted to estimate the number of outpatient cases. Among all adults ≥50 years, the incidence of hospitalized CAP per 100,000 person years was: 456.6 (CZ), 504.6 (SK), 363.9 (PL), and 845.3 (HU). The average fatality rate for all adults ≥50 is 19.1%, and for each country; 21.7% (CZ), 20.9% (SK), 18.6% (PL), 17.8% (HU). Incidence, fatality, and likelihood of hospitalization increased with advancing age. Total healthcare costs of CAP in EUR was 12,579,543 (CZ); 9,160,774 (SK); 22,409,085 (PL); and 18,298,449 (HU); with hospitalization representing over 90% of the direct costs of treatment. The burden of CAP increases with advancing age in four CEE countries, with hospitalizations driving the costs of CAP upwards in the elderly population. Mortality rates are generally higher than reported in Western EU countries. 相似文献