全文获取类型
收费全文 | 107721篇 |
免费 | 11365篇 |
国内免费 | 3283篇 |
专业分类
耳鼻咽喉 | 852篇 |
儿科学 | 1366篇 |
妇产科学 | 1127篇 |
基础医学 | 14699篇 |
口腔科学 | 3801篇 |
临床医学 | 11206篇 |
内科学 | 11248篇 |
皮肤病学 | 1452篇 |
神经病学 | 6807篇 |
特种医学 | 3320篇 |
外国民族医学 | 11篇 |
外科学 | 7262篇 |
综合类 | 15445篇 |
现状与发展 | 10篇 |
一般理论 | 3篇 |
预防医学 | 16987篇 |
眼科学 | 1338篇 |
药学 | 13920篇 |
113篇 | |
中国医学 | 5926篇 |
肿瘤学 | 5476篇 |
出版年
2024年 | 315篇 |
2023年 | 2260篇 |
2022年 | 3415篇 |
2021年 | 5992篇 |
2020年 | 5566篇 |
2019年 | 4847篇 |
2018年 | 4389篇 |
2017年 | 4600篇 |
2016年 | 4579篇 |
2015年 | 4513篇 |
2014年 | 7577篇 |
2013年 | 8002篇 |
2012年 | 7011篇 |
2011年 | 7318篇 |
2010年 | 5424篇 |
2009年 | 5066篇 |
2008年 | 4825篇 |
2007年 | 4781篇 |
2006年 | 4100篇 |
2005年 | 3591篇 |
2004年 | 2986篇 |
2003年 | 2734篇 |
2002年 | 2158篇 |
2001年 | 2056篇 |
2000年 | 1614篇 |
1999年 | 1408篇 |
1998年 | 1338篇 |
1997年 | 1225篇 |
1996年 | 1059篇 |
1995年 | 951篇 |
1994年 | 931篇 |
1993年 | 698篇 |
1992年 | 660篇 |
1991年 | 552篇 |
1990年 | 475篇 |
1989年 | 482篇 |
1988年 | 416篇 |
1987年 | 367篇 |
1986年 | 286篇 |
1985年 | 378篇 |
1984年 | 293篇 |
1983年 | 175篇 |
1982年 | 201篇 |
1981年 | 158篇 |
1980年 | 154篇 |
1979年 | 114篇 |
1978年 | 76篇 |
1977年 | 52篇 |
1976年 | 73篇 |
1974年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
21.
目的:山白树是中国特有珍稀濒危植物。分析微卫星特征,开发其微卫星分子标记。方法:采用Illumina二代测序技术建立山白树基因组文库和微卫星文库,分析微卫星组成类型,设计山白树引物,用5个山白树种群进行扩增和检测以分析其多态性。结果:二代测序共返回38,942,660条100 bp配对序列,通过质量修剪及拼接得到200,386条拼接序列,其中长度 335 bp的为7 614条;在7 614条序列中检测出微卫星位点694个,其中单核苷酸重复最多,单核苷酸重复中A/T重复数量最多;二核苷酸长度变异最大,其中AG/CT重复数量最多,重复长度变异情况与微卫星丰度呈正相关。为36条山白树微卫星重复次数高的序列设计引物,经聚合酶链式反应(PCR)扩增和聚丙烯酰胺凝胶电泳检测,20对引物多态性丰富且条带清晰,等位基因数(NA)在3~6之间,平均为4,多态性信息含量(PIC) 0. 535 5~0. 754 0,平均值0. 615 5。对5个山白树种群的群体遗传分析发现,该物种遗传多样性较高(h=0. 697 5,I=1. 436 8,HE=0. 702 2),种群遗传分化显著(Fst=0. 374)。结论:通过部分山白树的群体遗传也可以说明本次开发的引物可用性较好。该研究开发了山白树微卫星分子标记引物,为山白树分子遗传学奠定了基础。 相似文献
22.
María C. Lanuza-López Sandra G. Martínez-Garza Jesús F. Solórzano-Vázquez Daniela Paz-Cervantes Claudia González-Ortega Israel Maldonado-Rosas 《Gynecological endocrinology》2020,36(9):829-834
AbstractOocyte maturation defect is a challenging situation in the management of infertility, the etiology may be related to endocrine causes, protocols used in ovarian stimulation, oocyte intrinsic defects or procedures in embryology laboratory. We report three Mexican females in treatment for primary infertility with non-mature oocytes after ovary stimulation and oocyte capture in whom a genetic diagnosis of TUBB8-oocyte maturation defect was revealed by exome sequencing. Two couples achieved pregnancies though oocyte donation after establishing the genetic etiology. Our results expand the role of TUBB8-disorders in patients of non-Asian ethnicity. Oocyte maturation defects of monogenic origin are a growing group of disorders that endocrinologists and reproductive medicine specialists should be aware in order to provide referral to genetics for establish a correct and opportune diagnosis. 相似文献
23.
24.
Alexander E. J. Trevatt David R. Thomson Robert Miller Matthew Colquhoun Akinyemi I. Idowu Shakeel Rahman 《Journal of plastic surgery and hand surgery》2019,53(2):97-104
Academic output is just one aspect of a successful career as a plastic surgeon. However, for those with a strong interest in academia, the academic output of a department will likely be a key factor when deciding how to rank jobs. The aim of this study was to quantify and rank the academic output of plastic surgery units across the UK and Ireland. The Institute for Scientific Information (ISI) Web of Science Bibliometric analysis tool was used to collate cumulative (1950–2016), 10 year (2006–2016) and 3 years (2013–2015) research output data for plastic surgery units in the UK and Ireland. Sixty-six plastic surgery units were identified. Departments were ranked for each time period according to the number of papers produced, number of citations (Nc) and h-index (a measure of the impact of scientific output). The top 3 departments for number of papers in the last 10 years were The Royal Free Hospital, London (226) Broomfield Hospital, Chelmsford (218), and Morriston Hospital and Swansea (188). The top 3 for h-number were The Royal Free Hospital (21) Wythenshawe Hospital, Manchester (18) and Morriston Hospital (17). Academic output varies across plastic surgery units in the UK and Ireland. A number of departments have consistently maintained high academic outputs across the years and will be of interest to surgeons hoping to pursue a career in academia. 相似文献
25.
目的 按照国家计划抽验要求,评价国内不同企业生产的注射用盐酸柔红霉素的质量。方法 按国家标准检验与探索性研究相结合,对抽验样品进行检验,对检验结果进行统计分析。结果 共抽取样品17批次,按国家标准检验合格率100.0%。探索性研究对主要杂质的来源与结构进行了研究;建立溶液的澄清度检查方法;对包材相容性及稳定性进行了考察。结论 目前国内注射用盐酸柔红霉素总体质量较好;现行标准有待进一步提高,建议现行标准修订有关物质检查方法,增加特定杂质的控制,增加溶液的澄清度检查;建议企业优化生产工艺,以提高产品质量。 相似文献
26.
《Journal of pharmaceutical sciences》2019,108(11):3515-3520
Particle size analysis in the pharmaceutical industry has long been a source of debate regarding how best to define measurement accuracy; the degree to which the result of a measurement or calculation conforms to the true value. Defining a “true” value for the size of a particle can be challenging as the output of its measurement will differ because of variations in measurement approaches, instrumental differences and calculation methods. Consequently, for “real” particles, a universal “true” value does not exist and accuracy is therefore not a definable characteristic. Accordingly, precision is then a measure of the ability to reproducibly achieve a measurement of unknown relevance.This article proposes, in place of accuracy, a means to define the “appropriateness” of a measurement in line with the critical quality attributes (CQA) of the material being characterized. The decision as to whether the measurement is correct should involve a link to the CQA; that is, correlation should be demonstrated, without which the measured particle size cannot be defined as a critical material attribute.Correspondingly, methods should also be able to provide sufficient precision to demonstrate discrimination relating to variation in the CQA. The benefits and challenges of this approach are discussed. 相似文献
27.
中药生产过程质量控制关键技术研究进展 总被引:10,自引:8,他引:2
中医药发展已上升到国家战略层面,在医药行业贯彻实施"中国制造2025"战略的新形势下,中药生产过程质量控制是中药工业需要加快突破的关键领域之一。对中药生产过程质量控制领域在工艺设计、分析检测、过程建模、制造装备等方面的关键共性问题进行解析,综述了中药生产过程质量控制体系中工艺过程理解、生产过程实时分析方法开发、过程控制策略建立3个方面的研究进展;并结合企业研究实践,介绍了质量源于设计(quality by design,Qb D)、过程分析技术(process analytical technology,PAT)、实验设计(design of experiment,DOE)、多变量统计分析等关键技术在上述3个研究方向中的应用进展,分析了实际工业应用的难点问题并对其应用前景进行展望,旨在为中药企业应用和提升生产过程质量控制技术提供参考。 相似文献
28.
Jingjing He Lingyi Zhang Dan Guo Xingwen Han Hui Zhang Liang Wang Youcheng
Zhang 《Oncologie》2020,22(1):1-12
Hepatocellular carcinoma (HCC) ranks the sixth place of most common
cancers. Meanwhile, it is the tertiary mortality cause of cancer. There is no
effective therapeutic method to prevent and treat the liver cancer. Sinomenine is a
kind of Chinese traditional medicine herbal, it is reported that it can inhibit the
viability of several cancer cells. The study is to explore whether sinomenine is also
able to inhibit the cell viability of HCC and its potential mechanism. The IC50 of
sinomenine in BEL-7402 cells was 5.351 mmol/L, and the IC50 of sinomenine in
SMMC-7721 cells was 6.204 mmol/L. The gene expression results showed the
relative expression of FGF2, CCND2, DCN, F3, MMP7, NRG1, HMGB1,
TRIM29, HAS2, EHF, CTGF, PLK2 were down-regulated, and the relative
expression of VEGF A, CITED2, NUPR1, DDX58, IRF9, NAMPT, MMP1,
NDRG1, HMGA2, PPARGC1A, IFIT2, PARP9, HEY1, LOX, ETV1, ISG15,
BACH, CYLD were up-regulated. Moreover, the IPA analysis results suggested
that IFIT3, IFIT1, OAS1, MX1, IRF9, IFI6, IFITM1, ISG15 were up-regulated in
BEL-7402 cells treated with sinomenine by activating IFNA2. The findings
presented in this study may provide a promising method for the prevention and
treatment of liver cancer. 相似文献
29.
Martin R. Späth Malte P. Bartram Nicolàs Palacio-Escat K. Johanna R. Hoyer Cedric Debes Fatih Demir Christina B. Schroeter Amrei M. Mandel Franziska Grundmann Giuliano Ciarimboli Andreas Beyer Jayachandran N. Kizhakkedathu Susanne Brodesser Heike Göbel Jan U. Becker Thomas Benzing Bernhard Schermer Martin Höhne Markus M. Rinschen 《Kidney international》2019,95(2):333-349
30.
Whitney S. Brandt Wanpu Yan Jian Zhou Kay See Tan Joseph Montecalvo Bernard J. Park Prasad S. Adusumilli James Huang Matthew J. Bott Valerie W. Rusch Daniela Molena William D. Travis Mark G. Kris Jamie E. Chaft David R. Jones 《The Journal of thoracic and cardiovascular surgery》2019,157(2):743-753.e3