全文获取类型
收费全文 | 572篇 |
免费 | 32篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 23篇 |
妇产科学 | 8篇 |
基础医学 | 51篇 |
口腔科学 | 18篇 |
临床医学 | 62篇 |
内科学 | 127篇 |
皮肤病学 | 5篇 |
神经病学 | 51篇 |
特种医学 | 138篇 |
外科学 | 44篇 |
综合类 | 8篇 |
预防医学 | 22篇 |
眼科学 | 3篇 |
药学 | 37篇 |
中国医学 | 1篇 |
肿瘤学 | 21篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 10篇 |
2017年 | 8篇 |
2016年 | 12篇 |
2015年 | 8篇 |
2014年 | 12篇 |
2013年 | 20篇 |
2012年 | 17篇 |
2011年 | 18篇 |
2010年 | 15篇 |
2009年 | 17篇 |
2008年 | 16篇 |
2007年 | 26篇 |
2006年 | 12篇 |
2005年 | 15篇 |
2004年 | 13篇 |
2003年 | 13篇 |
2002年 | 11篇 |
2001年 | 11篇 |
2000年 | 7篇 |
1999年 | 13篇 |
1998年 | 34篇 |
1997年 | 22篇 |
1996年 | 27篇 |
1995年 | 18篇 |
1994年 | 22篇 |
1993年 | 14篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 14篇 |
1989年 | 21篇 |
1988年 | 29篇 |
1987年 | 13篇 |
1986年 | 16篇 |
1985年 | 17篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 10篇 |
1981年 | 5篇 |
1980年 | 12篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 8篇 |
1976年 | 6篇 |
1973年 | 1篇 |
1947年 | 1篇 |
排序方式: 共有622条查询结果,搜索用时 0 毫秒
1.
Release of soluble transferrin receptor from the surface of human leukemic HL60 cells 总被引:2,自引:0,他引:2
Information regarding transferrin (Tf) receptor degradation is largely incomplete. HL60 cells were shown to release to their growth medium a Tf-binding protein which could be immunoprecipitated by anti-Tf receptor monoclonal antibodies (MoAbs) B3/25 and OKT9. Soluble Tf receptor was detected in the medium within one hour of replating of cells, and its release was inhibited at 4 degrees C. The affinity of Tf for the soluble receptor released by cells (kd = 2.3 x 10(-10) mol/L) was slightly lower than its affinity for the detergent-solubilized cellular receptor (kd = 1.2 x 10(-10) mol/L). 125I-Tf internalized and released by cells subsequently bound to Tf receptor released by the same cells, and soluble Tf receptor in the conditioned medium (CM) inhibited 125I-Tf binding to intact cells. The soluble Tf receptor isolated from the CM was smaller (78,000 daltons) than the cell surface receptor (94,000 daltons) when analyzed by gel electrophoresis under reducing conditions. Isolated cell membranes readily released soluble receptor; however, this release could be blocked by protease inhibitors. The soluble Tf receptor may represent the extracytoplasmic domain of the cellular Tf receptor released from the surface of HL60 cells through proteolytic cleavage by a membrane-based protease. 相似文献
2.
3.
Molecular cloning and functional expression of two monocyte chemoattractant protein 1 receptors reveals alternative splicing of the carboxyl-terminal tails. 总被引:45,自引:0,他引:45 下载免费PDF全文
I F Charo S J Myers A Herman C Franci A J Connolly S R Coughlin 《Proceedings of the National Academy of Sciences of the United States of America》1994,91(7):2752-2756
Monocyte chemoattractant protein 1 (MCP-1) is a member of the chemokine family of cytokines that mediate leukocyte chemotaxis. The potent and specific activation of monocytes by MCP-1 may mediate the monocytic infiltration of tissues in atherosclerosis and other inflammatory diseases. We have isolated cDNAs that encode two MCP-1-specific receptors with alternatively spliced carboxyl tails. Expression of the receptors in Xenopus oocytes conferred robust mobilization of intracellular calcium in response to nanomolar concentrations of MCP-1 but not to related chemokines. The MCP-1 receptors are most closely related to the receptor for the chemokines macrophage inflammatory protein 1 alpha and RANTES (regulated on activation, normal T expressed and secreted). The identification of the MCP-1 receptor and cloning of two distinct isoforms provide powerful tools for understanding the specificity and signaling mechanisms of this important chemokine. 相似文献
4.
5.
Sanjana VM; Johnston PA; Robertson CR; Jamison RL 《The American journal of physiology》1976,231(2):313-318
6.
Localization of a gene for otosclerosis to chromosome 15q25-q26 总被引:5,自引:0,他引:5
Tomek MS; Brown MR; Mani SR; Ramesh A; Srisailapathy CR; Coucke P; Zbar RI; Bell AM; McGuirt WT; Fukushima K; Willems PJ; Van Camp G; Smith RJ 《Human molecular genetics》1998,7(2):285-290
Among white adults otosclerosis is the single most common cause of hearing
impairment. Although the genetics of this disease are controversial, the
majority of studies indicate autosomal dominant inheritance with reduced
penetrance. We studied a large multi- generational family in which
otosclerosis has been inherited in an autosomal dominant pattern. Five of16
affected persons have surgically confirmed otosclerosis; the remaining nine
have a conductive hearing loss but have not undergone corrective surgery.
To locate the disease- causing gene we completed genetic linkage analysis
using short tandem repeat polymorphisms (STRPs) distributed over the entire
genome. Multipoint linkage analysis showed that only one genomic region, on
chromosome 15q, generated a lod score >2.0. Additional STRPs were typed
in this area, resulting in a lod score of 3.4. STRPs FES (centromeric) and
D15S657 (telomeric) flank the 14. 5 cM region that contains an otosclerosis
gene.
相似文献
7.
Peritoneal fluid concentrations of interleukin-8 in women with endometriosis: relationship to stage of disease 总被引:7,自引:10,他引:7
Gazvani MR; Christmas S; Quenby S; Kirwan J; Johnson PM; Kingsland CR 《Human reproduction (Oxford, England)》1998,13(7):1957-1961
There is increasing evidence that immunological mechanisms play a role in
the pathogenesis and pathophysiology of endometriosis. It was therefore of
interest to study interleukin-8 (IL-8), a chemokine, in the peritoneal
fluid and peripheral blood of women undergoing laparoscopic procedures. The
presence and concentrations of IL-8 in relation to endometriosis,
infertility and abdominal pain were evaluated. Samples of peritoneal fluid
(n = 49) and peripheral blood (n = 50) were obtained from 50 consecutive
patients undergoing laparoscopic surgery for various gynaecological
indications (abdominal pain, infertility, sterilization). IL-8 was present
in the peritoneal fluid of most women (87%). The concentration of IL-8 in
the peritoneal fluid was higher in women with endometriosis compared to
women without (P = 0.02). This difference was more pronounced in early
(stage 1) endometriosis (P = 0.001). IL-8 concentrations in the peritoneal
fluid were also higher in women with early endometriosis compared to women
with later stages of the disease (P = 0.003). Peripheral blood
concentrations did not correlate with peritoneal fluid concentrations of
IL-8 and/or the presence of endometriosis. We conclude that IL-8 is an
important factor that may contribute to the pathogenesis of endometriosis
possibly by promoting neovascularization. This information can be a guide
in the development of new therapeutic approaches for the treatment of
endometriosis.
相似文献
8.
Clinical suppression of experimental allergic encephalomyelitis by muramyl dipeptide “adjuvant” 总被引:1,自引:0,他引:1
Robert Scott Root-Bernstein Franci Yurochko Fred C. Westall 《Brain research bulletin》1986,17(4):473-476
Experimental allergic encephalomyelitis (EAE) is a model for several human diseases including multiple sclerosis and post-vaccinal encephalopathies. EAE is generally thought to be an autoimmune response to the antigen myelin basic protein (MBP). Oddly, MBP can also suppress EAE, and many observations suggest that an independent immune response to so-called "adjuvant" material is also necessary to EAE induction. Thus, EAE may be a result of a pair of interactive immune responses, one against MBP, and one against adjuvant. If so, the adjuvant should, like MBP, suppress EAE. We present data from experiments on strain 13 guinea pigs demonstrating EAE suppression by muramyl dipeptide, an active component of complete Freund's adjuvant. These results are striking because classically adjuvants are defined as immunopotentiators, not immunosuppressants. Our results, therefore, suggest that a revaluation of the role of adjuvants in inducing autoimmune diseases may be necessary. 相似文献
9.
Luigi Gennari Daniela Merlotti Natale Figura Christian Mingiano Maria Beatrice Franci Barbara Lucani Tommaso Picchioni Mario Alessandri Maria Stella Campagna Sara Gonnelli Simone Bianciardi Maria Materozzi Carla Caffarelli Stefano Gonnelli Ranuccio Nuti 《Journal of bone and mineral research》2021,36(1):80-89
Helicobacter pylori (HP) infection is a common and persistent disorder acting as a major cofactor for the development of upper gastrointestinal diseases and several extraintestinal disorders including osteoporosis. However, no prospective study assessed the effects of HP on bone health and fracture risk. We performed a HP screening in a population-based cohort of 1149 adults followed prospectively for up to 11 years. The presence of HP infection was assessed by serologic testing for serum antibodies to HP and the cytotoxin associated gene-A (CagA). The prevalence of HP infection did not differ among individuals with normal bone mineral density (BMD), osteoporosis, and osteopenia. However, HP infection by CagA-positive strains was significantly increased in osteoporotic (30%) and osteopenic (26%) patients respect to subjects with normal BMD (21%). Moreover, anti-CagA antibody levels were significantly and negatively associated with lumbar and femoral BMD. Consistent with these associations, patients affected by CagA-positive strains had a more than fivefold increased risk to sustain a clinical vertebral fracture (HR 5.27; 95% CI, 2.23–12.63; p < .0001) and a double risk to sustain a nonvertebral incident fracture (HR 2.09; 95% CI, 1.27–2.46; p < .005). Reduced estrogen and ghrelin levels, together with an impaired bone turnover balance after the meal were also observed in carriers of CagA-positive HP infection. HP infection by strains expressing CagA may be considered a risk factor for osteoporosis and fractures. Further studies are required to clarify in more detail the underlying pathogenetic mechanisms of this association. © 2020 American Society for Bone and Mineral Research (ASBMR). 相似文献
10.
Chronic immobilization-induced stress increases plasma testosterone and delays testicular maturation in pubertal rats 总被引:2,自引:0,他引:2
We investigated whether chronic stress, applied from prepuberty to early puberty, interferes with the spermatogenic and androgenic testicular functions. Male pubertal rats (40 days old) were immobilized 6 h per day for 15 days. Plasma concentrations of corticosterone, prolactin and testosterone were significantly augmented following immobilization, whereas plasma luteinizing hormone decreased and follicle-stimulating hormone was not altered. Acute immobilization (5 min) increased prolactin and testosterone levels in control rats but caused a significantly higher increase in these hormones when superimposed on chronic stress. A lower extent of testicular maturation was observed in pubertal rats immobilized from prepuberty. 相似文献