全文获取类型
收费全文 | 8326篇 |
免费 | 645篇 |
国内免费 | 41篇 |
专业分类
耳鼻咽喉 | 56篇 |
儿科学 | 421篇 |
妇产科学 | 211篇 |
基础医学 | 1098篇 |
口腔科学 | 160篇 |
临床医学 | 1288篇 |
内科学 | 1311篇 |
皮肤病学 | 120篇 |
神经病学 | 650篇 |
特种医学 | 157篇 |
外科学 | 935篇 |
综合类 | 112篇 |
一般理论 | 6篇 |
预防医学 | 1037篇 |
眼科学 | 266篇 |
药学 | 683篇 |
中国医学 | 13篇 |
肿瘤学 | 488篇 |
出版年
2023年 | 40篇 |
2022年 | 72篇 |
2021年 | 173篇 |
2020年 | 113篇 |
2019年 | 156篇 |
2018年 | 151篇 |
2017年 | 129篇 |
2016年 | 131篇 |
2015年 | 176篇 |
2014年 | 240篇 |
2013年 | 381篇 |
2012年 | 486篇 |
2011年 | 598篇 |
2010年 | 321篇 |
2009年 | 293篇 |
2008年 | 522篇 |
2007年 | 550篇 |
2006年 | 554篇 |
2005年 | 555篇 |
2004年 | 509篇 |
2003年 | 407篇 |
2002年 | 470篇 |
2001年 | 115篇 |
2000年 | 106篇 |
1999年 | 102篇 |
1998年 | 115篇 |
1997年 | 80篇 |
1996年 | 69篇 |
1995年 | 53篇 |
1994年 | 64篇 |
1993年 | 52篇 |
1992年 | 87篇 |
1991年 | 73篇 |
1990年 | 74篇 |
1989年 | 56篇 |
1988年 | 63篇 |
1987年 | 62篇 |
1986年 | 65篇 |
1985年 | 58篇 |
1984年 | 61篇 |
1983年 | 50篇 |
1982年 | 57篇 |
1981年 | 52篇 |
1980年 | 52篇 |
1979年 | 36篇 |
1978年 | 34篇 |
1977年 | 27篇 |
1975年 | 26篇 |
1974年 | 31篇 |
1971年 | 31篇 |
排序方式: 共有9012条查询结果,搜索用时 31 毫秒
41.
Ronald M Grant Sheila S Weitzman Christopher G Sherman Wilma L Sirkin Martin Petric Raymond Tellier 《Journal of clinical virology》2002,24(1-2):7-12
BACKGROUND: Varicella Zoster virus (VZV) infection is potentially very serious in bone marrow transplant recipients, and may manifest as a disseminated visceral infection. This condition is generally accompanied by a vesicular rash. OBJECTIVES: We review here a case of fulminant fatal disseminated VZV infection, not accompanied by skin involvement, and the laboratory approaches currently available to diagnose this disease. STUDY DESIGN: Post mortem tissue samples were subjected to histopathological examination, and tested for herpesviruses by electron microscopy and PCR. RESULTS: Intranuclear inclusions were noted by histological examination in the lungs, liver, kidneys and bone marrow. Particles with a herpesvirus morphology were visualized in liver tissue. VZV DNA was detected in liver and bone marrow by PCR followed by sequencing of the amplicons. Viremia was documented by retrospective testing of the serum by PCR. CONCLUSIONS: A disseminated VZV infection which proved rapidly fatal was demonstrated in a case without skin manifestations. This rare presentation of VZV infection is potentially underdiagnosed. Testing for VZV viremia by PCR can at the very least suggest the diagnosis although whether plasma-associated viremia is truly pathognomonic of visceral disseminated infection remains to be established. 相似文献
42.
Fgf-10 is required for both limb and lung development and exhibits striking functional similarity to Drosophila branchless 总被引:11,自引:1,他引:11 下载免费PDF全文
Hosung Min Dimitry M. Danilenko Sheila A. Scully Brad Bolon Brian D. Ring John E. Tarpley Margaret DeRose W. Scott Simonet 《Genes & development》1998,12(20):3156-3161
Fgf-10-deficient mice (Fgf-10−/−) were generated to determine the role(s) of Fgf-10 in vertebrate development. Limb bud initiation was abolished in Fgf-10−/− mice. Strikingly, Fgf-10−/− fetuses continued to develop until birth, despite the complete absence of both fore- and hindlimbs. Fgf-10 is necessary for apical ectodermal ridge (AER) formation and acts epistatically upstream of Fgf-8, the earliest known AER marker in mice. Fgf-10−/− mice exhibited perinatal lethality associated with complete absence of lungs. Although tracheal development was normal, main-stem bronchial formation, as well as all subsequent pulmonary branching morphogenesis, was completely disrupted. The pulmonary phenotype of Fgf-10−/− mice is strikingly similar to that of the Drosophila mutant branchless, an Fgf homolog. 相似文献
43.
44.
Many residues involved in polymorphic antibody-binding epitopes on class II molecules are located on the -helix of DRβ chains. Although they have received less attention, residues in the peptide-binding groove and second domain of the DRβ chain may also be critical for polymorphic anti-DR antibody epitopes. In this study, we used transfectants expressing site-directed mutations at positions in the HLA-DR β1 and β2 domains and flow cytometry to define the epitopes of several polymorphic anti-DR antibodies. Both DR(β 1*0403) residues 14 and 25 were shown to be involved in the epitopes of mAbs DA6. 164, HU-20, Q5/6, and 50D6, and DR(β 1*0701) residue 14 was shown to be critical for the epitopes of two DR7-specific mAbs, SFR16-DR7M and TAL 13. 1. Unlike most other residues shown to be important in antibody-binding epitopes, residue 14 is located in the floor of the peptide-binding groove and residue 25 is in an outer loop, each with their side chains pointing down, such that antibodies may directly contact these residues from below the binding groove. Two residues in the β2 domain, β180 and β181, were also shown to be involved in the epitopes of three polymorphic anti-DR mAbs, NFLD.D1, NFLD.M1, and LY9. Although these two residues are close to the transmembrane domain in the linear sequence, their solvent accessibility in the DR1 structures is quite impressive. Our data provide new evidence that residues accessible under the peptidebinding groove contribute to polymorphic antibody-binding epitopes. 相似文献
45.
46.
Cell-mediated and humoral immune responses induced by scarification vaccination of human volunteers with a new lot of the live vaccine strain of Francisella tularensis. 下载免费PDF全文
D M Waag A Galloway G Sandstrom C R Bolt M J England G O Nelson J C Williams 《Journal of clinical microbiology》1992,30(9):2256-2264
Tularemia is a disease caused by the facultative intracellular bacterium Francisella tularensis. We evaluated a new lot of live F. tularensis vaccine for its immunogenicity in human volunteers. Scarification vaccination induced humoral and cell-mediated immune responses. Indications of a positive immune response after vaccination included an increase in specific antibody levels, which were measured by enzyme-linked immunosorbent and immunoblot assays, and the ability of peripheral blood lymphocytes to respond to whole F. tularensis bacteria as recall antigens. Vaccination caused a significant rise (P less than 0.05) in immunoglobulin A (IgA), IgG, and IgM titers. Lymphocyte stimulation indices were significantly increased (P less than 0.01) in vaccinees 14 days after vaccination. These data verify that this new lot of live F. tularensis vaccine is immunogenic. 相似文献
47.
48.
Isolation of exfoliated colonocytes from human stool as a new technique for colonic cytology 总被引:4,自引:0,他引:4
Bandaletova T Bailey N Bingham SA Loktionov A 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2002,110(3):239-246
Cell exfoliation in the gut is an important cell renewal mechanism. To approach its investigation we applied a novel immunomagnetic technique for isolation of exfoliated cells from human stool. Exfoliated colonocytes were isolated from 168 stool samples. The cells were assessed microscopically using conventional stains and immunohistochemistry. The technique allowed us to obtain well-preserved colonocytes displaying characteristic features of well-differentiated colonic epithelium and positive immunostaining for cytokeratin 5/8. No mucin-producing cells were found. Exfoliated cells did not produce inducible nitric oxide synthase, albeit cultured colon carcinoma cells HT-29 analysed in parallel showed strong immunostaining. Analysis of exfoliated cell numbers in consecutive stool samples from the same subjects revealed considerable interindividual variation. Overall exfoliated colonocyte numbers were relatively low, isolation being unaffected by addition during the procedure of excessive amounts of HT-29 cells. Apoptosis was extremely rare among exfoliated colonocytes. Well-preserved exfoliated colonocytes can be consistently isolated from human faeces using a simple procedure. Our findings suggest that the actual process of cell exfoliation in the human colon may be much less intense than is generally accepted. Exfoliated cell isolation from human stool constitutes a convenient non-invasive approach that can be used for diagnostic and research purposes. 相似文献
49.
Sheila G. Haworth Susan M. Hall Michael Chew Kim Allen 《Virchows Archiv : an international journal of pathology》1987,411(2):161-171
Summary Adaptation to extra-uterine life and postnatal remodelling of intra-acinar arteries was followed in 34 Large White pigs, from birth to adult life, applying morphometry to light and electronmicroscopic studies. After birth, percentage wall thickness decreased rapidly due to a reduction in overlap of adjacent smooth muscle cells and an increase in smooth muscle cell surface area/volume ratio, (p<0.01 at 12 h), without a reduction in the volume density of smooth muscle cells. Smooth muscle cells appeared immature at birth and synthetic rather than contractile organelles predominated. Between 3 weeks and 6 months myofilament volume density doubled (p< 0.0001). At all ages, pericytes, intermediate and smooth muscle cells showed similar volume densities of contractile and synthetic organelles. Thus, the high fetal pulmonary vascular resistance appeared to be due to the shape and arrangement of smooth muscle and other contractile cells within the vessel wall, rather than an excessive contractility of these cells. After birth rapid remodelling of arterial wall structure achieved a reduction in wall thickness by 30 min, continuing during the first week of life. After 3 weeks, remodelling involved an increase in wall thickness, connective tissue deposition with more collagen than elastin (p<0.0001), and smooth muscle cell differentiation. 相似文献
50.
Primary myeloid sarcoma of the testicle with t(15;17) 总被引:1,自引:0,他引:1
The first case of acute promyelocytic leukemia presenting as a solitary testicular mass (myeloid sarcoma) that relapsed in the contralateral testicle is described. The neoplastic cells strongly expressed chloroacetate esterase, myeloperoxidase, CD33, CD43, and weakly, CD117. The presence of many azurophil granules and Auer rods was detected by electron microscopy. Translocation (15;17)(q22;q21.1) was revealed by cytogenetics and was verified by fluorescence in situ hybridization. Contralateral testicle is a favorite site for recurrence in a subset of testicular myeloid sarcomas. Subclassification of all cases of myeloid sarcoma ought to be attempted. 相似文献