全文获取类型
收费全文 | 4148篇 |
免费 | 357篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 149篇 |
妇产科学 | 198篇 |
基础医学 | 586篇 |
口腔科学 | 92篇 |
临床医学 | 398篇 |
内科学 | 630篇 |
皮肤病学 | 72篇 |
神经病学 | 317篇 |
特种医学 | 227篇 |
外国民族医学 | 1篇 |
外科学 | 598篇 |
综合类 | 123篇 |
一般理论 | 3篇 |
预防医学 | 603篇 |
眼科学 | 29篇 |
药学 | 233篇 |
中国医学 | 3篇 |
肿瘤学 | 237篇 |
出版年
2021年 | 70篇 |
2020年 | 44篇 |
2019年 | 66篇 |
2018年 | 75篇 |
2017年 | 59篇 |
2016年 | 62篇 |
2015年 | 45篇 |
2014年 | 101篇 |
2013年 | 141篇 |
2012年 | 170篇 |
2011年 | 195篇 |
2010年 | 92篇 |
2009年 | 87篇 |
2008年 | 168篇 |
2007年 | 184篇 |
2006年 | 179篇 |
2005年 | 168篇 |
2004年 | 179篇 |
2003年 | 164篇 |
2002年 | 155篇 |
2001年 | 169篇 |
2000年 | 148篇 |
1999年 | 119篇 |
1998年 | 58篇 |
1997年 | 38篇 |
1996年 | 29篇 |
1995年 | 33篇 |
1994年 | 41篇 |
1993年 | 34篇 |
1992年 | 105篇 |
1991年 | 91篇 |
1990年 | 76篇 |
1989年 | 88篇 |
1988年 | 88篇 |
1987年 | 79篇 |
1986年 | 70篇 |
1985年 | 62篇 |
1984年 | 48篇 |
1983年 | 49篇 |
1982年 | 38篇 |
1981年 | 28篇 |
1980年 | 30篇 |
1979年 | 61篇 |
1978年 | 51篇 |
1977年 | 39篇 |
1975年 | 25篇 |
1974年 | 42篇 |
1973年 | 34篇 |
1972年 | 31篇 |
1970年 | 27篇 |
排序方式: 共有4510条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
Nora Franceschini Kari E North Jeffrey B Kopp Louise McKenzie Cheryl Winkler 《Genetics in medicine》2006,8(2):63-75
Nephrotic syndrome, characterized by edema, proteinuria, hyperlipidemia and low serum albumin, is a manifestation of kidney disease involving the glomeruli. Nephrotic syndrome may be caused by primary kidney disease such as focal segmental glomerulosclerosis. Mutations in the podocin gene, NPHS2, have been shown in familial and sporadic forms of steroid-resistant nephrotic syndrome, including focal segmental glomerulosclerosis. Podocin is an integral membrane protein located at the slit diaphragm of the glomerular permeability barrier. Complete information is lacking for the population frequency of some NPHS2 variants for all racial and ethnic groups. The most frequently reported variant, R229Q, is more common among European-derived populations than African-derived populations. We calculated crude odds ratios and 95% confidence intervals of childhood nephrotic syndrome and focal segmental glomerulosclerosis associated with R229Q heterozygosity using data from five studies. The R229Q variant is not associated with focal segmental glomerulosclerosis in the US population of African descent. In contrast, the R229Q variant is associated with a trend toward increased focal segmental glomerulosclerosis risk in European-derived populations, with an estimated increased risk of 20-40%. Our insight into the association between NPHS2 variants and nephrotic disease is hampered by the limitations of the existing studies, including small numbers of affected individuals and suboptimal control groups. Nevertheless, the available data suggest that large epidemiological case-control studies to examine the association between NPHS2 variants and nephrotic syndrome are warranted. 相似文献
45.
P Lebrun A H Lucas D T McKenzie H L Spiegelberg 《International archives of allergy and applied immunology》1989,88(1-2):108-110
Murine B cells were activated for 24 h with either lipopolysaccharide (LPS) or polyribosyl-ribitol-phosphate (PRP), followed by addition of interleukin 4 (IL-4) and the immunoglobulin isotypes secreted into the supernatant quantitated. Without IL-4, both LPS and PRP induced mainly IgM and IgG3 and no IgE secretion. Addition of IL-4 to both LPS- and PRP-activated cells decreased the IgM and IgG3 secretion and induced a large IgG1 production. In contrast to IgG1, only LPS-activated cells secreted large amounts of IgE, demonstrating that the nature of the polyclonal B cell activator also plays an important role in the IL-4 induced IgE formation. The effect of LPS and IL-4 on high- and low-density sIgM+/sIgD+ cells was also investigated. LPS and IL-4 induced IgG1 and IgE secretion by both populations. Low-density B cells from mice infected with the parasite Nippostrongylus brasiliensis formed more IgE than low-density B cells from normal mice, presumably because these mice have more in vivo preactivated B cells committed to IgE formation. The data show that IL-4 can act on both small high-density resting B cells as well as on in vivo preactivated low-density B cells to induce IgG1 and IgE secretion. 相似文献
46.
Guo L Hu-Li J Zhu J Pannetier C Watson C McKenzie GJ McKenzie AN Paul WE 《Nature immunology》2001,2(5):461-466
Interleukin 13-deficient (IL-13-/-) mice express a defect in priming for IL-4 production that is not corrected by adding IL-13 to the priming culture. This is partly accounted for by the consumption of IL-4 without endogenous replacement during culture of IL-13-/- CD4+ T cells. We examined cells from mice in which disrupted Il13 was linked to wild-type Il4 on one chromosome and wild-type Il13 was linked to a "knocked-in" green fluorescent protein (Gfp) gene in the Il4 locus. Our results show that the deficit in IL-4 production was due, at least in part, to a cis effect, in which disrupted Il13 diminished IL-4 production from the linked Il4 gene. 相似文献
47.
Mauro S. Sandrin Ian F. C. McKenzie Roger W. Melvold Günter J. Hmmerling 《European journal of immunology》1982,12(3):205-209
The B6.C-H-2bm12 has been examined serologically with a new set of reagents and several complementation studies were performed to determine the extent of the mutation. The results show that: (a) the mutation has also affected the site(s) bound by xenogeneic anti-Ia antibodies; (b) the IJb region was not affected; (c) complementation studies with stains bearing a, b, d, k and s haplotypes did not complement bm12 for the expression of the lost I-Ab specificities, suggesting a structural (rather than regulatory) gene alteration in bm12; (d) H-2 haplotypes b and bm12 could complement d to establish the Ia.22 specificity, indicating that Ia-1 and Ae are separate genes in the I-A subregion. In addition, an antibody to the gained specificity on bm12 is described. 相似文献
48.
McKenzie BS Corbett AJ Brady JL Dyer CM Strugnell RA Kent SJ Kramer DR Boyle JS Lew AM 《Immunologic research》2001,24(3):225-244
There are no adequate vaccines against some of the new or reemerged infectious scourges such as HIV and TB. They may require
strong and enduring cell-mediated immunity to be elicited. This is quite a task, as the only known basis of protection by
current commercial vaccines is antibody. As DNA or RNA vaccines may induce both cell-mediated and humoral immunity, great
interest has been shown in them. However, doubt remains whether their efficacy will suffice for their clinical realization.
We look at the various tactics to increase the potency of nucleic acid vaccines and divided them broadly under those affecting
delivery and those affecting immune induction. For delivery, we have considered ways of improving uptake and the use of bacterial,
replicon or viral vectors. For immune induction, we considered aspects of immunostimulatory CpG motifs, coinjection of cytokines
or costimulators and alterations of the antigen, its cellular localization and its anatomical localization including the use
of ligand-targeting to lymphoid tissue. We also thought that mucosal application of DNA deserved a separate section. In this
review, we have taken the liberty to discuss these enhancement methods, whenever possible, in the context of the underlying
mechanisms that might argue for or against these strategies. 相似文献
49.
Interleukin-9 is a cytokine produced by Th2 cells and is a candidate gene for asthma and atopy. We have generated IL-9-deficient mice to delineate the specific roles of IL-9 in Th2 responses. Using a pulmonary granuloma model, we have demonstrated a distinct requirement for IL-9 in the rapid and robust generation of pulmonary goblet cell hyperplasia and mastocytosis in response to lung challenge. In contrast, eosinophilia and granuloma formation were not affected. IL-9 was not required for T cell development or differentiation, the generation of naive or antigen-driven antibody responses, or the expulsion of the intestinal parasitic nematode Nippostrongylus brasiliensis. Thus, deletion of IL-9 manifests as a highly defined phenotype in Th2 responses modulating mucus production and mast cell proliferation. 相似文献
50.
Intrafractional motion during proton beam scanning 总被引:2,自引:0,他引:2
Lambert J Suchowerska N McKenzie DR Jackson M 《Physics in medicine and biology》2005,50(20):4853-4862
Patient and internal organ motion during treatment with a scanned proton beam can introduce unplanned heterogeneities in the dose distribution throughout the irradiated volume. With static beam techniques, a margin around the target volume is added to compensate for patient and organ motion. This margin may not provide the solution with dynamic beam scanning. Intrafractional motion parallel and perpendicular to the beam axis is studied using two different scanning methods on a cubic water phantom. The direction of motion relative to the beam scanning direction as well as the method of scanning the proton beam across the target has a significant effect on the resulting dose distribution within the target volume. In the extreme cases studied here up to 100% of the target receives a dose outside the recommended limits, with a minimum dose as low as 34% of the prescribed dose. 相似文献