全文获取类型
收费全文 | 20376篇 |
免费 | 1765篇 |
国内免费 | 1223篇 |
专业分类
耳鼻咽喉 | 205篇 |
儿科学 | 370篇 |
妇产科学 | 404篇 |
基础医学 | 4397篇 |
口腔科学 | 382篇 |
临床医学 | 2061篇 |
内科学 | 4037篇 |
皮肤病学 | 493篇 |
神经病学 | 833篇 |
特种医学 | 320篇 |
外国民族医学 | 12篇 |
外科学 | 1333篇 |
综合类 | 3183篇 |
现状与发展 | 5篇 |
预防医学 | 971篇 |
眼科学 | 290篇 |
药学 | 1433篇 |
2篇 | |
中国医学 | 139篇 |
肿瘤学 | 2494篇 |
出版年
2024年 | 58篇 |
2023年 | 401篇 |
2022年 | 800篇 |
2021年 | 1136篇 |
2020年 | 754篇 |
2019年 | 696篇 |
2018年 | 558篇 |
2017年 | 506篇 |
2016年 | 601篇 |
2015年 | 747篇 |
2014年 | 1041篇 |
2013年 | 1040篇 |
2012年 | 1152篇 |
2011年 | 1332篇 |
2010年 | 1193篇 |
2009年 | 1224篇 |
2008年 | 1222篇 |
2007年 | 1151篇 |
2006年 | 1057篇 |
2005年 | 912篇 |
2004年 | 670篇 |
2003年 | 563篇 |
2002年 | 450篇 |
2001年 | 476篇 |
2000年 | 479篇 |
1999年 | 435篇 |
1998年 | 453篇 |
1997年 | 385篇 |
1996年 | 242篇 |
1995年 | 318篇 |
1994年 | 262篇 |
1993年 | 162篇 |
1992年 | 131篇 |
1991年 | 87篇 |
1990年 | 81篇 |
1989年 | 61篇 |
1988年 | 56篇 |
1987年 | 40篇 |
1986年 | 35篇 |
1985年 | 62篇 |
1984年 | 39篇 |
1983年 | 28篇 |
1982年 | 27篇 |
1981年 | 40篇 |
1980年 | 45篇 |
1979年 | 22篇 |
1978年 | 30篇 |
1977年 | 17篇 |
1976年 | 29篇 |
1975年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
聚合酶链反应诊断单纯疱疹病毒性脑炎 总被引:5,自引:0,他引:5
用聚合酶链反应(PCR)扩增患者脑脊液(ChF)中病毒特异性DNA可早期快速诊断单纯疱疹病毒性脑炎(HSE)。19例临床确诊的病毒性脑炎患者,经PCR在CSF中检出单纯疱疹病毒(HSV)13例,全部阳性标本均经分子杂交证实为HSV-DNA,而14例其他神经疾病(OND)对照组均为阴性,显示了这一方法的特异性。其中7例病毒性脑炎CSF标本分别用PCR分子杂交和病毒分离等三种方法检测HSV;显示PCR最为敏感。表明PCR技术的广泛应用将提高HSE的早期诊断水平,指导临床正确治疗。 相似文献
32.
创面异体移植培养表皮细胞后存活的判定 总被引:1,自引:0,他引:1
应用4种方法判定烧伤创面异体移植的培养表皮细胞存活情况:1.聚合酶链反应(PCR)查Y染色体特异性DNA片段;2.PCR扩增PMCT118长度多态性基因位点;3.PCR/SSOHLA-DQa分型;4.DNA指纹。共检测16例病人的27个活检标本,均证实有供者的DNA,最长时间为移植后92天。初步实验结果表明:培养表皮异体移植后可存活较长时间。 相似文献
33.
Early erythroid precursors were studied in human bone marrow smears to provide more information on small proerythroblasts--"microproerythroblasts"--using a silver reaction to demonstrate silver stained nucleolar organizer regions (AgNORs) and light microscopic densitometry of large irregularly shaped nucleoli and cytoplasm stained for RNA. No significant differences were found for the density of such nucleoli and basophilic cytoplasm between characteristic large proerythroblasts with a nuclear diameter larger that 9 microm (K2 and K1 erythroblasts) and small proerythroblasts--"microproerythroblasts" representing a subpopulation of K1/2 erythroblasts (early basophilic erythroblasts), which are characterized by a smaller nuclear diameter. In addition, large irregularly shaped nucleoli of "microproerythroblasts" possessed numerous silver stained particles representing AgNORs similar to those of large proerythroblasts. The number of AgNORs in "microproerythroblasts" was slightly, but significantly, smaller than that in large characteristic proerythroblasts. 相似文献
34.
K. Nagamani Manisha Rani Vishnuvardhan Reddy Panduranga Rao Sushma Rajyalakshmi Sunitha Pakalapaty 《Indian journal of medical microbiology》2022,40(1):12-17
PurposeNoroviruses are common viral agents in acute diarrhea in all age groups worldwide. Norovirus has been classified into 10 genogroups, GI to GX with over 48 genotypes among them the GII.4 genotype has evolved over time with a clear pattern of periodic variant replacement. Immunity is strain or genotype specific with little or no protection conferred across genogroups. The present study was aimed to determine the epidemiology, prevalent genotypes of norovirus in children below five years of age in the Hyderabad region, India.MethodsThe stool samples and clinical data were collected from 458 children below 5 years of age comprising of cases with acute gastroenteritis (n ?= ?366) and a control group (n ?= ?92) admitted to the pediatric ward. All the samples were tested for Norovirus by ELISA and RT-PCR. Sequencing was done for predominant strains.Results10.3% (n ?= ?38) of cases and 3.2% (n ?= ?3) of the control group were found to be Norovirus positive. Predominant genotypes were GII-82.5% followed by GI-12.5%.ConclusionSequencing and Phylogenetic analyses of 20 GII.4 strains was done. All of the isolates are clustered away from published the GII.4 variants thus suggesting the appearance of a new variant. 相似文献
35.
36.
37.
对12例经病理学专家会诊、从病变上认定的淋巴结“结节病”石蜡包埋组织,应用结核杆菌DNA特异性序列片段的聚合酶链反应(M.TB-PCR)技术、BCG免疫组化(BCG-IHC)技术和抗酸染色(AF)进行了分支杆菌/结核杆菌检测。在这12例考虑为“结节病”的病例中:有1例呈BCG-IHC和M。TB-PCR两项阳性;另1例呈AF、BCG-IHC和M.TB-PCR三项阳性。研究结果提示:(1)某些结核性淋巴结炎可呈结节病样病变;(2)淋巴结结节病很可能与分支杆菌/结核杆菌感染有关。 相似文献
38.
L. A. Kopteva L. I. Zhevalyukova V. I. Biryuzova 《Bulletin of experimental biology and medicine》1978,86(3):1160-1163
Acute cardiac ischemia caused by ligation of the descending branch of the left coronary artery leads to a sharp increase in the activity of the protein-synthesizing system of the inner mitochondrial membranes of the myocardium throughout the period of organization of the experimental infarct, as reflected in an incease in the synthesis of protein and RNA in the mitochondria. During development of the infarct considerable changes are observed in the ultrastructure of the inner mitochondrial membranes of the myocardium, the degree of which is directly dependent on the stage of development of the pathological process.Institute of General Pathology and Pathophysiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. N. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 9, pp. 295–297, September, 1978. 相似文献
39.
Lance S. Davidow Matthew Breen Shannon E. Duke Paul B. Samollow John R. McCarrey Jeannie T. Lee 《Chromosome research》2007,15(2):137-146
X-chromosome inactivation (XCI) evolved in mammals to deal with X-chromosome dosage imbalance between the XX female and the
XY male. In eutherian mammals, random XCI of the soma requires a master regulatory locus known as the ‘X-inactivation center’
(XIC/Xic), wherein lies the noncoding XIST/Xist silencer RNA and its regulatory antisense Tsix gene. By contrast, marsupial XCI is imprinted to occur on the paternal X chromosome. To determine whether marsupials and
eutherians share the XIC-driven mechanism, we search for the sequence equivalents in the genome of the South American opossum, Monodelphis domestica. Positional cloning and bioinformatic analysis reveal several interesting findings. First, protein-coding genes that flank
the eutherian XIC are well-conserved in M. domestica, as well as in chicken, frog, and pufferfish. However, in M. domestica we fail to identify any recognizable XIST or TSIX equivalents. Moreover, cytogenetic mapping shows a surprising break in synteny with eutherian mammals and other vertebrates.
Therefore, during the evolution of the marsupial X chromosome, one or more rearrangements broke up an otherwise evolutionarily
conserved block of vertebrate genes. The failure to find XIST/TSIX in M. domestica may suggest that the ancestral XIC is too divergent to allow for detection by current methods. Alternatively, the XIC may have arisen relatively late in mammalian evolution, possibly in eutherians with the emergence of random XCI. The latter
argues that marsupial XCI does not require XIST and opens the search for alternative mechanisms of dosage compensation. 相似文献
40.