全文获取类型
收费全文 | 2687篇 |
免费 | 293篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 33篇 |
儿科学 | 68篇 |
妇产科学 | 48篇 |
基础医学 | 443篇 |
口腔科学 | 60篇 |
临床医学 | 272篇 |
内科学 | 618篇 |
皮肤病学 | 54篇 |
神经病学 | 110篇 |
特种医学 | 74篇 |
外科学 | 406篇 |
综合类 | 135篇 |
预防医学 | 186篇 |
眼科学 | 154篇 |
药学 | 157篇 |
1篇 | |
中国医学 | 16篇 |
肿瘤学 | 177篇 |
出版年
2023年 | 36篇 |
2022年 | 42篇 |
2021年 | 90篇 |
2020年 | 72篇 |
2019年 | 111篇 |
2018年 | 104篇 |
2017年 | 95篇 |
2016年 | 72篇 |
2015年 | 87篇 |
2014年 | 119篇 |
2013年 | 131篇 |
2012年 | 174篇 |
2011年 | 165篇 |
2010年 | 103篇 |
2009年 | 90篇 |
2008年 | 141篇 |
2007年 | 139篇 |
2006年 | 155篇 |
2005年 | 126篇 |
2004年 | 128篇 |
2003年 | 109篇 |
2002年 | 95篇 |
2001年 | 52篇 |
2000年 | 56篇 |
1999年 | 59篇 |
1998年 | 25篇 |
1997年 | 19篇 |
1995年 | 15篇 |
1994年 | 19篇 |
1993年 | 20篇 |
1992年 | 29篇 |
1991年 | 35篇 |
1990年 | 27篇 |
1989年 | 20篇 |
1988年 | 13篇 |
1987年 | 15篇 |
1986年 | 20篇 |
1985年 | 15篇 |
1984年 | 10篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1975年 | 10篇 |
1974年 | 10篇 |
1973年 | 10篇 |
1971年 | 10篇 |
1968年 | 9篇 |
1966年 | 8篇 |
排序方式: 共有3012条查询结果,搜索用时 13 毫秒
31.
Mice injected subcutaneously with 1 x 10(8) sheep red blood cells (SRBC) developed high levels of delayed-type hypersensitivity (DTH) to SRBC 4-8 days after injection. Such DTH was suppressed when 100 microgram lipopolysaccharide (LPS) was injected intravenously 1-2 days before or at the time of SRBC injection. This suppression of DTH was transferable by spleen, lymph node, thymus and bone marrow cells to sensitized or normal syngeneic recipients, but could not be transferred by serum. Suppressor cells were not induced by LPS alone or SRBC alone, and they were antigen-specific since DTH to chicken red blood cells was not affected. The suppressor cells appeared in the spleen in optimum number 3-4 days after induction. They were theta-negative and Ig-positive as judged by antiserum plus complement treatment and by Ig rosette separation. Attempts to obtain soluble suppressor factor from the suppressor cells by sonication or in vitro incubation were unsuccessful. Mitomycin C treatment of the suppressor cells completely abolished the suppressor activity. Thus, LPS, in conjunction with antigen, appears to induce a population of specific suppressor B cells which are capable of regulating T cell function. 相似文献
32.
33.
Mice injected in the footpad with carrageenin developed local inflammation which peaked at 48 hr. This delayed-type footpad swelling was significantly reduced in mice injected intraperitoneally (i.p.) with a specific nitric oxide (NO) synthase inhibitor, L-NGmonomethyl-arginine (L-NMMA). The draining lymph node (DLN) cells from mice injected 48 hr previously with carrageenin produced significantly higher levels of proliferation and interleukin-1 (IL-1), IL-2, IL-6 and interferon-gamma (IFN-gamma), but less IL-10, compared to cells from saline-injected controls, when stimulated with concanavalin A (Con A) in vitro. Treatment of the carrageenin-injected mice with L-NMMA had little effect on the proliferative response of the DLN cells, but significantly reduced the production of IL-1, IL-2, IL-6 and IFN-gamma, and increased the secretion of IL-10. These data demonstrate that NO plays a significant role in local inflammation and the pattern of cytokines induced in this model. 相似文献
34.
New aspects of vaccine development. 总被引:1,自引:1,他引:1
F Y Liew 《Clinical and experimental immunology》1985,62(2):225-241
35.
In this article is a summary of our recent findings on the role of nitric oxide (NO) as an effector mechanism against the intracellular parasite, Leishmania major. NO is produced in large amounts in murine macrophages following activation by IFNgamma synthesized by Th1 cells. NO production is inhibited by IL-4, a product of Th2 cells. A set of stable cell surface markers has now been identified. ST2L and IL-18R are selectively expressed on Th2 and Th1 cells respectively. Antibody against ST2L can down-regulate Th2 cells in the highly susceptible BALB/c mice leading to control of otherwise fatal L. major infection. These results show directly the critical role of the balance between Th1 and Th2 cells in cutaneous leishmaniasis. 相似文献
36.
Ozer E Sengül AM Gedik S Salman S Salman F Sargin M Işsever H Satman I Yilmaz T 《Patient education and counseling》2003,51(1):39-44
To examine the influence of diabetes education on well-being, 255 patients with type 2 diabetes were recruited according to whether they attended a diabetes education program (n=126) or not (n=129). In patients who had participated in the program, the mean anxiety score was significantly lower, whereas positive well-being and general well-being scores were significantly higher than for patients who had not participated. Factors related to lower well-being included: being female, taking insulin, not attending a diabetes education program and having HbA(1c) level greater than 8%. The odds of having better well-being were two-fold higher in patients participating the diabetes education program compared with those who had not. Diabetes education has a crucial role in improving the well-being of patients with type 2 diabetes. All patients with diabetes should be encouraged to attend a diabetes education program. 相似文献
37.
Murphy M Mabruk MJ Lenane P Liew A McCann P Buckley A O Flatharta C Hevey D Billet P Robertson W Javed S Leader M Kay E Murphy GM 《Journal of clinical pathology》2002,55(11):829-833
AIM: Ultraviolet light (UV) is known to cause DNA damage in the epidermis. The damaged DNA is repaired or deleted by apoptosis to prevent the generation of cancer. It has been suggested that a deficient apoptotic mechanism may predispose individuals to skin cancer. Therefore, the response of normal controls and patients with basal cell carcinoma (BCC) to UV irradiation was investigated. METHODS: The buttock skin from normal volunteers and patients with BCC was irradiated using solar simulated radiation (SSR). SSR mimics the effect of natural sunlight. Skin biopsies were excised and examined for p53, p21, and Bax protein expression and for the induction of apoptosis. RESULTS: At 33 hours after UV irradiation, the induction of apoptosis was significantly higher (p = 0.04) in patients with BCC than in normal volunteers (Mann Whitney test). A trend towards higher p21 expression was found at 33 hours in patients with BCC (mean, 18.69 positive cells/field) than in normal volunteers (mean, 9.89), although this difference was not significant (p = 0.05 positive cells/field). CONCLUSION: These results may imply that patients with BCC have enhanced sensitivity to UV irradiation or that there is some defect in the cell arrest or repair pathways, which results in damaged cells been pushed into apoptosis rather than repair. 相似文献
38.
The PTPN22 R620W polymorphism associates with RF positive rheumatoid arthritis in a dose-dependent manner but not with HLA-SE status 总被引:10,自引:0,他引:10
Lee AT Li W Liew A Bombardier C Weisman M Massarotti EM Kent J Wolfe F Begovich AB Gregersen PK 《Genes and immunity》2005,6(2):129-133
We have recently described the association between rheumatoid arthritis and a coding single-nucleotide polymorphism in the intracellular protein tyrosine phosphatase, PTPN22. The disease-associated polymorphism, 1858 C/T (rs2476601), encodes an amino-acid change (R620W) in one of four SH3 domain binding sites in the PTPN22 molecule. We have now extended our initial studies to address three questions: (1) Is the association with rheumatoid arthritis limited to rheumatoid factor (RF) positive disease? (2) Does homozygosity for PTPN22 R620W substantially increase disease susceptibility? (3) Is there an interaction between PTPN22 and the rheumatoid arthritis (RA)-associated HLA-DRB1 shared epitope alleles? A total of 1413 Caucasian rheumatoid arthritis patients and 1401 Caucasian controls were genotyped. The results support the view that PTPN22 was strongly and preferentially associated with RF positive disease (OR=1.75, 95% CI 1.46-2.10, P=1.3 x 10(-9)). The PTPN22 risk allele was not significantly associated with RF negative disease (OR=1.19, 95% CI 0.92-1.53, P=0.18), although a very weak association cannot be completely excluded. There was a strong dose effect on disease risk; two copies of the PTPN22 R620W allele more than doubles the risk for RF positive RA (OR=4.57, 95% CI 2.35-8.89). There was no evidence of a genetic association between PTPN22 and HLA susceptibility alleles. 相似文献
39.
Alison Severn Damo Xu Jacqueline Doyle Ludmila M. C. Leal Catherine A. O'Donnell Sara J. Brett David W. Moss Foo Y. Liew 《European journal of immunology》1993,23(7):1711-1714
Murine macrophages produce nitric oxide (NO) from L-arginine on stimulation with lipopolysaccharide (LPS), alone or with interferon-γ (IFN-γ). The effect of incubation of macrophages with low concentrations of LPS on NO synthesis on subsequent stimulation was investigated, using a murine macrophage cell line, J774, and peritoneal macrophages from CBA mice. Cells which had been incubated with LPS produced significantly lower amounts of NO, and expressed lower levels of NO synthase activity, following stimulation with IFN-γ and LPS, or with a high concentration of LPS. This effect was not reversed by tumor necrosis factor-α. The ability of CBA macrophages to kill the intracellular parasite Leishmania major was markedly reduced by pre-incubation with LPS. Reduced NO production by macrophages previously exposed to LPS is a manifestation of endotoxin tolerance, and may represent an important means of regulation of NO synthesis and thus a survival mechanism for intracellular parasites. 相似文献
40.
The Toll-IL-1 receptor (TIR) superfamily, defined by the presence of an intracellular TIR domain, initiates innate immunity via NF-kappaB activation, leading to production of proinflammatory cytokines. ST2 is a member of the TIR family that does not activate NF-kappaB and has been suggested as an important effector molecule of type 2 T helper cell responses. We have recently demonstrated that the membrane bound form of ST2 (ST2L) negatively regulated IL-1RI and TLR4 but not TLR3 signaling by sequestrating the adaptors MyD88 and Mal. In contrast to wild-type mice, ST2 deficient mice failed to develop endotoxin tolerance. Thus, ST2 suppresses IL-1R and TLR4 signaling via MyD88- and Mal-dependent pathways and modulates innate immunity. The results provide a molecular explanation for the role of ST2 in T(H)2 responses since inhibition of TLRs will promote a T(H)2 response and also identify ST2 as a key regulator of endotoxin tolerance. 相似文献