全文获取类型
收费全文 | 1144706篇 |
免费 | 80553篇 |
国内免费 | 2927篇 |
专业分类
耳鼻咽喉 | 15043篇 |
儿科学 | 38693篇 |
妇产科学 | 31870篇 |
基础医学 | 166156篇 |
口腔科学 | 32550篇 |
临床医学 | 98730篇 |
内科学 | 226110篇 |
皮肤病学 | 26927篇 |
神经病学 | 90917篇 |
特种医学 | 41936篇 |
外国民族医学 | 305篇 |
外科学 | 166526篇 |
综合类 | 24441篇 |
一般理论 | 408篇 |
预防医学 | 95508篇 |
眼科学 | 26523篇 |
药学 | 83201篇 |
3篇 | |
中国医学 | 2609篇 |
肿瘤学 | 59730篇 |
出版年
2021年 | 9108篇 |
2019年 | 9881篇 |
2018年 | 15061篇 |
2017年 | 11013篇 |
2016年 | 12111篇 |
2015年 | 13662篇 |
2014年 | 17765篇 |
2013年 | 27158篇 |
2012年 | 38076篇 |
2011年 | 40377篇 |
2010年 | 23209篇 |
2009年 | 20868篇 |
2008年 | 36638篇 |
2007年 | 38892篇 |
2006年 | 39090篇 |
2005年 | 37371篇 |
2004年 | 36130篇 |
2003年 | 34597篇 |
2002年 | 33243篇 |
2001年 | 51110篇 |
2000年 | 52732篇 |
1999年 | 43852篇 |
1998年 | 11811篇 |
1997年 | 10484篇 |
1996年 | 10545篇 |
1995年 | 10121篇 |
1994年 | 9379篇 |
1992年 | 34177篇 |
1991年 | 33215篇 |
1990年 | 32742篇 |
1989年 | 31355篇 |
1988年 | 28603篇 |
1987年 | 28644篇 |
1986年 | 26816篇 |
1985年 | 25889篇 |
1984年 | 19307篇 |
1983年 | 16311篇 |
1982年 | 9686篇 |
1979年 | 17933篇 |
1978年 | 12913篇 |
1977年 | 10992篇 |
1976年 | 10394篇 |
1975年 | 10945篇 |
1974年 | 13326篇 |
1973年 | 12905篇 |
1972年 | 11883篇 |
1971年 | 11087篇 |
1970年 | 10271篇 |
1969年 | 9693篇 |
1968年 | 9087篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
María Cabrerizo Gloria Trallero María José Pena Amaia Cilla Gregoria Megias Carmen Mu?oz-Almagro Eva Del Amo Diana Roda Ana Isabel Mensalvas Antonio Moreno-Docón Juan García-Costa Nuria Rabella Manuel Ome?aca María Pilar Romero Sara Sanbonmatsu-Gámez Mercedes Pérez-Ruiz María José Santos-Mu?oz Cristina Calvo And the study group of “Enterovirus parechovirus infections in children under ?years-old Spain” PI- 《European journal of pediatrics》2015,174(11):1511-1516
102.
Carlos A. ávila-Orta Zoe V. Qui?ones-Jurado Miguel A. Waldo-Mendoza Erika A. Rivera-Paz Víctor J. Cruz-Delgado José M. Mata-Padilla Pablo González-Morones Ronald F. Ziolo 《Materials》2015,8(11):7900-7912
Isotactic polypropylenes (iPP) with different melt flow indexes (MFI) were used to fabricate nanocomposites (NCs) with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs) using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 1013 to 105 Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods. 相似文献
103.
104.
Umar Nadia K. Badshah Maaz B. Sandrasegaran Kumar Ghabril Marwan Agarwal Saurabh Tann Mark Lacerda Marco Kwo Paul Y. 《Digestive diseases and sciences》2015,60(7):2196-2200
Digestive Diseases and Sciences - To determine whether the presence of portal vein thrombosis (PVT) where venous flow within the liver may be altered may delay the diagnosis of HCC and be... 相似文献
105.
Antonio Sierra-Cedillo Miriam Figueroa-Olea Silvia Izazola-Ezquerro Rolando Rivera-González 《Early child development and care》2019,189(6):883-895
The concept of participation was reviewed as a component of children's citizenship in order to promote a programme for Integral Development. A narrative revision of the literature was carried out as well as a group discussion was organized along with the staff of an Integral Care Programme, in order to identify notions of democracy and child citizenship related to care and rearing. Some elements that favoured the child participation and some parenting skills were identified. Among the elements that must be encouraged in children are: the development of emotional, cognitive and communicative skills and promotion of decision-making; among the parent skills development included are: sensitivity and responsivity; establishing routines and participation experiences. It is important to stand out that the identified elements to promote child participation and parental competences should be adapted to every specific cultural context. 相似文献
106.
Letter: faecal volatile organic metabolites,promising biomarkers in inflammatory bowel disease and Letter: faecal volatile organic metabolites as novel diagnostic biomarkers in inflammatory bowel disease. Authors’ reply 下载免费PDF全文
I. Ahmed R. Greenwood B. Costello N. Ratcliffe C. Probert 《Alimentary pharmacology & therapeutics》2016,43(11):1241-1242
107.
108.
109.
Jennifer L. Brown Lisa B. Haddad Nicole K. Gause Sarah Cordes Cecilia Bess Caroline C. King 《Women & health》2019,59(3):305-317
This study qualitatively examined factors that influenced contraceptive choices in a sample of young, HIV-infected women. Individual qualitative interviews were conducted among 30 vertically and horizontally HIV-infected women (n = 26 African American) from the ages of 14 to 24 years (Mean age = 20.9 years). We recruited sample groups with the following characteristics: (a) current contraceptive/condom use with ≥1 child (n = 11); (b) current contraceptive/condom use with no children (n = 12); and (c) no current contraceptive/condom use with no children (n = 7). A semi-structured interview guide was used to ask participants about factors influencing past and current contraceptive choices. Individual interviews were digitally recorded and transcribed verbatim; analyses to identify core themes were informed by the Grounded Theoretical approach. Young, HIV-infected women did not identify their HIV serostatus or disease-related concerns as influential in their contraceptive decisions. However, they reported that recommendations from health-care providers and input from family and friends influenced their contraceptive choices. They also considered a particular method’s advantages (e.g., menstrual cycle improvements) and disadvantages (e.g., increased pill burden) when selecting a method. Findings suggested that HIV-infected young women’s contraceptive decisions were influenced by factors other than those related to their infection. 相似文献
110.
J. Rodríguez-Carrio A. Martínez-Zapico I. Cabezas-Rodríguez L. Benavente Á.I. Pérez-Álvarez P. López J.B. Cannata-Andía M. Naves-Díaz A. Suárez 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2019,29(2):135-143