全文获取类型
收费全文 | 14774篇 |
免费 | 738篇 |
国内免费 | 100篇 |
专业分类
耳鼻咽喉 | 144篇 |
儿科学 | 209篇 |
妇产科学 | 109篇 |
基础医学 | 1736篇 |
口腔科学 | 270篇 |
临床医学 | 878篇 |
内科学 | 3759篇 |
皮肤病学 | 259篇 |
神经病学 | 1166篇 |
特种医学 | 797篇 |
外科学 | 2621篇 |
综合类 | 64篇 |
预防医学 | 487篇 |
眼科学 | 330篇 |
药学 | 959篇 |
中国医学 | 56篇 |
肿瘤学 | 1768篇 |
出版年
2023年 | 107篇 |
2022年 | 202篇 |
2021年 | 384篇 |
2020年 | 190篇 |
2019年 | 272篇 |
2018年 | 313篇 |
2017年 | 305篇 |
2016年 | 359篇 |
2015年 | 359篇 |
2014年 | 480篇 |
2013年 | 562篇 |
2012年 | 859篇 |
2011年 | 974篇 |
2010年 | 587篇 |
2009年 | 465篇 |
2008年 | 853篇 |
2007年 | 884篇 |
2006年 | 858篇 |
2005年 | 935篇 |
2004年 | 836篇 |
2003年 | 827篇 |
2002年 | 853篇 |
2001年 | 238篇 |
2000年 | 220篇 |
1999年 | 258篇 |
1998年 | 236篇 |
1997年 | 160篇 |
1996年 | 177篇 |
1995年 | 146篇 |
1994年 | 135篇 |
1993年 | 124篇 |
1992年 | 162篇 |
1991年 | 106篇 |
1990年 | 123篇 |
1989年 | 114篇 |
1988年 | 87篇 |
1987年 | 76篇 |
1986年 | 75篇 |
1985年 | 62篇 |
1984年 | 55篇 |
1983年 | 44篇 |
1982年 | 40篇 |
1981年 | 31篇 |
1979年 | 33篇 |
1975年 | 31篇 |
1974年 | 32篇 |
1973年 | 42篇 |
1969年 | 38篇 |
1968年 | 35篇 |
1967年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Immunofluorescence technique using HeLa cells expressing recombinant nucleoprotein for detection of immunoglobulin G antibodies to Crimean-Congo hemorrhagic fever virus
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Saijo M Qing T Niikura M Maeda A Ikegami T Sakai K Prehaud C Kurane I Morikawa S 《Journal of clinical microbiology》2002,40(2):372-375
A HeLa cell line continuously expressing recombinant nucleoprotein (rNP) of the Crimean-Congo hemorrhagic fever virus (CCHFV) was established by transfection with an expression vector containing the cDNA of CCHFV NP (pKS336-CCHFV-NP). These cells were used as antigens for indirect immunofluorescence (IF) to detect immunoglobulin G antibodies to CCHFV. The sensitivity and specificity of this IF technique were examined by using serum samples and were compared to those of the IF technique using CCHFV-infected Vero E6 cells (authentic antigen). Staining of the CCHFV rNP expressed in HeLa cells showed a unique granular pattern similar to that of CCHFV-infected Vero E6 cells. Positive staining could easily be distinguished from a negative result. All 13 serum samples determined to be positive by using the authentic antigen were also determined to be positive by using CCHFV rNP-expressing HeLa cells (recombinant antigen). The 108 serum samples determined to be negative by using the authentic antigen were also determined to be negative by using the recombinant antigen. Thus, both the sensitivity and the specificity of this IF technique were 100% compared to the IF with authentic antigen. The novel IF technique using CCHFV rNP-expressing HeLa cells can be used not only for diagnosis of CCHF but also for epidemiological studies on CCHFV infections. 相似文献
73.
Werner syndrome is a premature aging disease caused by the mutation in the WRN gene. The cloning andcharacterization of the WRN gene and its product allows investigators to study the disease and the human aging process atmolecular level. This review summarizes the recent progresses on various aspects of the WRN research including functionalanalysis of the protein, interactive cloning, complexes formation, mouse models, and SNPs (single nucleotidepolymorphisms). These in depth investigations have greatly advanced our understanding of the disease and elucidated futureresearch direction for Werner syndrome and the human aging process. 相似文献
74.
Miodrag ?oli? Vesna Ili? Milo? D. Pavlovi? Takuya Tamatani Masayuki Miyasaka 《Clinical & developmental immunology》1996,5(1):37-51
The effects of monoclonal antibodies (mAbs) to cell-surface molecules, divalent cations,
and various cell-signaling and metabolic inhibitors on the binding of thymocytes to rat
thymic dendritic cells (TDC) were studied using a rosette assay. It was found that TDC/thymocyte adhesion was stronger and faster at 37°C than at 4°C. Flow cytometric analysis demonstrated that bound thymocytes were predominantly CD4+CD8+ and CD4+CD8-, but in comparison to the phenotype of whole thymocytes, they were enriched in the mature
TCRαβhi subset. The binding of thymocytes to TDC at 37°C was almost completely
dependent on Ca2+ and Mg2+ and partly on an intact cytoskeleton and calmodulin-dependent
protein kinase. The adhesion was independent of new protein synthesis and the activities of protein kinases A and C, tyrosine kinases, as well as phosphotyrosine protein phosphatases. The TDC/thymocyte adhesion at 37°C was partly blocked by anti-LFA-1
(WT.1), anti-CD18 (WT.3), and anti-ICAM-1 (1A29) mAb. MAbs to class II MHC (OX-3 and OX-6), CD4 (W3/25), CD8 (OX-8), and αβTCR (R73) stimulated the adhesion via an LFA-1-dependent pathway, whereas an anti-CD45 mAb (G3C5) stimulated the rosette formation
independently of LFA-1. MAbs to CD2 (OX-34), CD11b (ED7), CD11b/c (OX-42), and class I MHC (OX-18) were without significant effects on the adhesion process. 相似文献
75.
76.
An invasion-independent pathway of blood-borne metastasis: a new murine mammary tumor model
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Sugino T Kusakabe T Hoshi N Yamaguchi T Kawaguchi T Goodison S Sekimata M Homma Y Suzuki T 《The American journal of pathology》2002,160(6):1973-1980
It is generally believed that active invasion by cancer cells is essential to the metastatic process. In this report, we describe a murine mammary tumor (MCH66) model of metastasis that does not require invasion into the vascular wall of both the primary tumor and the target organ, in this case, the lung. The process involves intravasation of tumor nests surrounded by sinusoidal blood vessels, followed by intravascular tumor growth in the lung, without penetration of the vascular wall during the process. Comparative studies using a nonmetastatic MCH66 clone (MCH66C8) and another highly invasive metastatic cell line (MCH416) suggested that high angiogenic activity and sinusoidal remodeling of tumor blood vessels were prerequisites for MCH66 metastasis. Differential cDNA analysis identified several genes that were overexpressed by MCH66, including genes for the angiogenesis factor pleiotrophin, and extracellular matrix-associated molecules that may modulate the microenvironment toward neovascularization. Our analyses suggest that tumor angiogenesis plays a role in the induction of invasion-independent metastasis. This model should prove useful in screening and development of new therapeutic agents for cancer metastasis. 相似文献
77.
78.
H. Yamada Y.-M. Jiang S. Oshima K. Wada F. Goshima T. Daikoku Y. Nishiyama 《Archives of virology》1998,143(6):1199-1207
Summary. We have identified the herpes simplex virus type 2 (HSV-2) UL4 gene product using a rabbit polyclonal antiserum raised against
a recombinant 6xHis-UL4 fusion protein expressed in Escherichia coli. The antiserum reacted specifically with a 27-kDa protein in HSV-2 186-infected cell lysates. The protein was not detectable
in the presence of the viral DNA synthesis inhibitor, suggesting that the UL4 gene was expressed as a γ2 gene. Indirect immunofluorescence studies localized the UL4 protein within the nucleus as discrete punctate forms at late
times postinfection. However, when expressed in the absence of other viral proteins, the UL4 protein was limited to the cytoplasm,
indicating that an interaction with one or more other virus-induced proteins was responsible for the nuclear localization
during infection. Subnuclear fractionation studies showed that the protein was released from the nuclear structure of infected
cells by high salt treatment. Moreover, the UL4 protein was detected in purified virions and light particles.
Received December 24, 1997 Accepted February 4, 1998 相似文献
79.
The patterns of DNA degradation in frozen, methanol-fixed, and formalin-fixed tissues were investigated by high-performance liquid chromatography (HPLC). The chromatograms all yielded one major peak with or without several extra minor peaks representing molecular weights of preserved genomic DNA. The most characteristic differences were in the retention times of the major peaks, with the earliest major peak occurring in the formalin-fixed tissues, and followed by the methanol-fixed, and frozen tissue samples, in that order. This means that the molecular weight of the DNA from formalin-fixed tissue is much shortened than that recovered from methanol-fixed tissue and frozen tissue. The results also indicated that a small amount of higher molecular weight DNA is still preserved in formalin-fixed tissues. To improve the amplification efficiency of polymerase chain reaction (PCR) analysis of formalin-fixed material, we isolated the higher molecular weight DNA from formalin-fixed, paraffin-embedded tissue from four different organs and compared the amplification efficiencies with those of the crude DNA extract. We used eight sets of oligonucleotide primers producing 262 to 989 base pair (bp) fragments of beta-globin. The results showed that the PCR amplification analyses were more efficient with the isolated higher molecular weight DNA than with the crude DNA extract. Our study demonstrated that not all the DNA in formalin-fixed, paraffin-embedded tissue samples is totally degraded but that a small amount of higher molecular weight DNA persists. The feasibility of molecular diagnosis using formalin-fixed material can be improved by isolating the preserved higher molecular weight DNA by HPLC. 相似文献
80.
Otsuka Y Ito M Yamaguchi M Saito S Uesu K Kasai K Abiko Y Mega J 《Mechanisms of ageing and development》2002,123(6):663-674
It is well known that Down syndrome (DS) is a premature ageing syndrome. Periodontal disease in individuals with DS develops rapidly and extensively in a relatively younger age bracket compared with that in healthy controls. The mechanisms involved in the periodontal inflammatory processes in DS patients are not fully understood. In the present study, the non-inflamed gingival fibroblasts isolated from seven patients with DS (DGF) and seven healthy controls (NDGF) were stimulated with lipopolysaccharide (LPS) derived from Actinobacillus actinomycetemcomitans (A. a.). We measured the level of prostaglandin E2 (PGE2) production by DGF and NDGF by radioimmunoassay, and also measured the mRNA expression of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) by using the real-time PCR method. We found the higher levels of LPS-stimulated COX-2 mRNA expression and PGE2 production in DGF when compared with those in NDGF. This study may indicate that overexpression of LPS-stimulated COX-2 induced a greater ability of DGF to produce PGE2, and that these phenomena may be responsible for the severer periodontal disease in DS patients. 相似文献