全文获取类型
收费全文 | 158881篇 |
免费 | 12545篇 |
国内免费 | 5451篇 |
专业分类
耳鼻咽喉 | 1537篇 |
儿科学 | 2931篇 |
妇产科学 | 1577篇 |
基础医学 | 23723篇 |
口腔科学 | 3125篇 |
临床医学 | 15648篇 |
内科学 | 20483篇 |
皮肤病学 | 1527篇 |
神经病学 | 7484篇 |
特种医学 | 3353篇 |
外国民族医学 | 28篇 |
外科学 | 15631篇 |
综合类 | 25373篇 |
现状与发展 | 11篇 |
一般理论 | 25篇 |
预防医学 | 10921篇 |
眼科学 | 4249篇 |
药学 | 16602篇 |
20篇 | |
中国医学 | 7930篇 |
肿瘤学 | 14699篇 |
出版年
2024年 | 326篇 |
2023年 | 1847篇 |
2022年 | 3922篇 |
2021年 | 5452篇 |
2020年 | 4832篇 |
2019年 | 5023篇 |
2018年 | 4964篇 |
2017年 | 4899篇 |
2016年 | 5068篇 |
2015年 | 5120篇 |
2014年 | 7987篇 |
2013年 | 9003篇 |
2012年 | 7559篇 |
2011年 | 8752篇 |
2010年 | 7700篇 |
2009年 | 7596篇 |
2008年 | 7661篇 |
2007年 | 8776篇 |
2006年 | 8065篇 |
2005年 | 8039篇 |
2004年 | 6996篇 |
2003年 | 6303篇 |
2002年 | 4687篇 |
2001年 | 4624篇 |
2000年 | 3759篇 |
1999年 | 3467篇 |
1998年 | 2482篇 |
1997年 | 2203篇 |
1996年 | 2262篇 |
1995年 | 2153篇 |
1994年 | 1893篇 |
1993年 | 1718篇 |
1992年 | 1476篇 |
1991年 | 1273篇 |
1990年 | 1072篇 |
1989年 | 1011篇 |
1988年 | 948篇 |
1987年 | 743篇 |
1986年 | 560篇 |
1985年 | 632篇 |
1984年 | 653篇 |
1983年 | 402篇 |
1982年 | 512篇 |
1981年 | 430篇 |
1980年 | 370篇 |
1979年 | 305篇 |
1978年 | 253篇 |
1977年 | 210篇 |
1976年 | 243篇 |
1975年 | 152篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Bonnet F Savès M Morlat PH Droz C Chêne G Peuchant E Bernard N Lacoste D Salamon R Beylot J 《Journal of clinical immunology》2002,22(2):75-82
We assessed the correlations between some plasma markers of immune activation (soluble receptors of interleukin 2 (sIL2-R) and TNFp75 (sTNFII-R) and usual markers of HIV infection in patients treated with protease-inhibitors (PI). Forty-six PI-naive HIV-1-infected adults were included in a 1-year prospective cohort from the initiation of a PI-containing regimen (M0). Measurements of CD4+cell count, plasma HIV-RNA, sIL2-R and sTNFII-R were performed at M0, M6, and M12. The evolution of sIL2-R from baseline to M12 was significantly different between immunological responders (IR) (CD4+count above 200/mm3 for subject having less than 200 CD4 +/mm3 at inclusion, or increase of at least 50 CD4+/mm3 for others) (58 UI/ml) and non-IR (+28 UI/ml) (P =0.01). The evolution of sTNFII-R between M0 and M12 was significantly different between virological responders (VR) (plasma HIV-1 RNA less than 500 copies/ml at M12) (–2.5 ng/ml) and non-VR (+0.2 ng/ml) (P =0.02). Our study shows significative correlations between the evolutions of soluble interleukin-2 and TNFR-II receptors and those of CD4+T-lymphocytes or HIV-RNA responses in patients under HAART. 相似文献
992.
目的 探讨聚乳酸.羟基乙酸共聚物[poly(D,L-lactic-co-glycolic)acid,PLGA]包裹的卵清蛋白(OVA)纳米癌苗(POM)对哮喘小鼠的免疫治疗效果.方法 包裹不同剂量(低、中、高)的OVA纳米粒子和对照(OVA、空白纳米粒子、PBS)通过皮下注射给予小鼠,再用OVA进行致敏和激发,通过肺组织学、支气管肺泡灌洗液(BALF)细胞计数、测定BALF和脾细胞培养上清液中细胞因子的含量,观察小鼠呼吸道炎症和免疫学改变.结果 肺部组织学和BALF中细胞计数结果显示,与PBS对照组相比,OVA治疗组、中剂量和高剂量OVA纳米组的肺部嗜酸性浸润显著减轻,BALF中总细胞和嗜酸性细胞显著减少.卸胞因子测定结果显示,与PBS对照组相比,中、高剂量OVA纳米组的BALF和脾细胞培养上清液中IFN-γ显著升高,Ⅱ,4水平显著降低.OVA治疗组中IL-4水平显著下降,而IFN-γ水平无显著差异.结论 OVA纳米疫苗可预防哮喘嗜酸性气道炎症,其可能的机制之一是调节了过敏性哮喘的Th1/Th2失平衡反应. 相似文献
993.
Saito N Takahashi M Akahata W Ido E Hidaka C Ibuki K Miura T Hayami M Takahashi H 《Tissue antigens》2005,66(6):674-682
The hereditary conservation in the genetically encoded CD1D sequences of various primates was analyzed. Genomic CD1D sequences of 17 rhesus macaques with distinct origins, eight Indian and nine Chinese, were examined and differences of only one or two nucleotides were detected and the consensus sequence of rhesus CD1D was determined. CD1D consensus sequences of three African green monkeys (AGMs) and the rhesus monkeys were then compared to study the evolutionary differences among interspecies. The CD1D consensus sequence determined from AGMs apparently differed by seven nucleotides from the rhesus consensus sequence, and nucleotide difference induced only three amino acid changes within Exon3, corresponding to the alpha2 domain of CD1d having a hydrophobic ligand-binding pocket. Such changes in the alpha2 domain may alter the characteristics of the SIV-derived glycolipid/lipid antigens presented by each CD1d molecule to innate natural killer T cells. In addition, the CD1D genomic sequences of three chimpanzees (chimps) were determined. To our surprise, although Exon2 and Exon3 reflecting antigen-binding alpha1 and alpha2 domains in chimps' CD1D were identical to that in humans except one amino acid, three amino acids within Exon4, reflecting alpha3 domain, were distinct from humans, and one of them was identical to those in rhesus and AGM CD1D. On the basis of the findings, the evolutionary relationship of the CD1d molecules among the various primates and their HIV-1/SIV susceptibility will be discussed. 相似文献
994.
Increased c-Fos/activator protein-1 confers resistance against anergy induction on antigen-specific T cell 总被引:1,自引:0,他引:1
Kawasaki H Nakata Y Suzuki G Chihara K Tokuhisa T Shiozawa S 《International immunology》1999,11(12):1873-1880
We have studied the contribution of c-Fos/activator protein-1 (AP-1) to antigen-specific T cell response with reference to T cell anergy by increasing c-Fos/AP-1 in vivo and in vitro. First, after injection of a high dose of staphylococcus enterotoxin B (SEB), clonal deletion of SEB-reactive V(beta)8(+) CD4 T cells occurred both in control B6 and H2-c-fos transgenic (fos) mice, whereas proliferation of T cells against SEB was profoundly depressed in B6 but not in fos mice. Second, the keyhole limpet hemocyanin-specific CD4 T(h)1 cell clone produced decreasing amounts of IL-2 in response to increasing amounts of concanavalin A (Con A) in vitro, whereas the decrease was less significant in the T(h)1 clones stably transfected with c-fos gene. Electrophoretic mobility shift assay with nuclear protein from the transformants showed that overexpression of the c-fos gene compensated the amounts of AP-1 in the nuclei of Con A-treated T(h)1 clones. Thus, increased c-Fos/AP-1 confers resistance against anergy induction on antigen-specific T cells. 相似文献
995.
996.
Yoshihisa Umekita Nobumasa Enokizono Yoshiatsu Sagara Kazumi Kuriwaki Takashi Takasaki Aichi Yoshida Hiroki Yoshida 《Virchows Archiv : an international journal of pathology》1992,420(4):345-351
Summary In this investigation, 83 human mammary carcinomas were examined for the expression of oestrogen receptor (ER), epidermal growth factor receptor (EGF-R), epidermal growth factor (EGF), transforming growth factor alpha (TGF-), c-erbB-2, histological grade, mitotic index and nodal status, all of which are reportedly prognostically significant factors (Bloom and Richardson 1957; Baak et al. 1985; Wright et al. 1989). ER expression was biochemically recognized in 43.4% of mammary carcinomas, and EGF-R, EGF, TGF- and c-erbB-2 were histochemically recognized in 25.3, 14.5, 27.7 and 18.0% of mammary carcinomas examined respectively, using conventional sections of buffered formalin-fixed, paraffin-embedded tissue and monoclonal or polyclonal antibodies. There were significant relationships between negative ER and positive EGF-R or TGF-; positive EGF-R and TGF-; positive EGF-R and c-erbB-2; and positive c-erbB-2 and TGF-. The single changes which were the negative ER and the positive c-erbB-2 correlated with histological grade and mitotic index. Co-expression of EGF-R and TGF- correlated with positive nodal status. Therefore, the present investigation indicates that the negative ER, single expression of c-erbB-2 and co-expression of EGF-R and TGF- are important markers which contribute indirectly to prognosis, which reconfirms previous findings on the former two while adding the new finding that immuno-histochemical demonstration of expression of EGF-R and TGF- may provide useful information for selecting the appropriate treatment. 相似文献
997.
Maintained pregnancy levels of oestrogen afford complete protection from post-partum exacerbation of collagen-induced arthritis. 总被引:4,自引:2,他引:4 下载免费PDF全文
R Mattsson A Mattsson R Holmdahl A Whyte G A Rook 《Clinical and experimental immunology》1991,85(1):41-47
Pregnancy is known to influence the course of rheumatoid arthritis (RA) in women, as well as type II collagen-induced arthritis (CIA) in DBA/1 mice. A characteristic feature is the remission during gestation and the exacerbation of the diseases during the post-partum period. In the case of CIA in DBA 1 mice, two hormonal changes have been assumed to be critical for the induction of the post-partum flare: (i) the fall in steroid hormone levels from those present during pregnancy; and (ii) surges of prolactin (PRL) release at and after delivery. Our results show that treatment with oestradiol during a short period immediately after parturition protects the mouse from a post-partum flare of the disease, and that treatment with bromocriptine, a drug known to inhibit the endogenous PRL release, has a significant though less marked effect. Studies of lactating (i.e. animals with physiological stimulation of endogenous PRL release) and non-lactating arthritic mice revealed no clear-cut differences, indicating that PRL is of minor importance for the induction of the post-partum flare. Some steroids other than oestradiol, which may be implicated in the exacerbation of arthritis, namely progesterone and hydrocortisone, had no clinical effect. Analyses of agalactosyl IgG levels in mice with CIA, and anti-collagen II antibodies in sera collected at the end of the experiments revealed no significant differences between the oestradiol and the control groups. The successful oestradiol treatment of the mice indicates that the drop in endogenous oestradiol levels prior to delivery ends the oestrogen-mediated protection against arthritis during pregnancy. 相似文献
998.
Unusual cytogenetic findings were noted in the leukemic cells from a patient with congenital acute monocytic leukemia (AMol or M5, according to the FAB classification), whereas, the chromosomes of cultured skin fibroblasts were normal. G-banded karyotypes of leukemic cells showed an X-autosome translocation, 46,X,t(X;10)(Xpter----q13::10q11.2----qter)(10pter---- q11.2::Xq28----q13:: Xq28----qter). Review of reported cases of acute nonlymphocytic leukemia (ANLL) with rearrangements involving chromosomes #10 or X showed a high frequency of abnormalities of the short arm of #10 in myelomonocytic (M4) and monocytic (M5) leukemias, particularly in patients less than 2-yr-of-age. Although previously reported cases of ANLL in infants are predominantly of these types, the translocation observed in this case is unique. Fragile sites known to exist on chromosomes #10 and X are not associated with neoplasia and, except for Xq27-28, were not at the breakpoints of the case presented. The precise location of a human cellular oncogene recently identified on the X chromosome remains unknown. 相似文献
999.
L Léger Y Charnay J A Chayvialle A Bérod F Dray J F Pujol M Jouvet P M Dubois 《Neuroscience》1983,8(3):525-546
The distribution of tyrosine hydroxylase-, substance P- and enkephalin-immunoreactive neurons in the cat dorsolateral pons was studied using the indirect immunofluorescence method of Coons. To allow for the visualization of substance P- and enkephalin-immunoreactive cell bodies, colchicine was injected either in the ventricular space or in the cerebral tissue. The distribution of the tyrosine hydroxylase-immunoreactive cell bodies corresponded with the well-known distribution of catecholamine cells in this area of the brain. The observation of adjacent sections treated separately with tyrosine hydroxylase- and enkephalin-antiserum revealed that most catecholaminergic cells contain enkephalin-immunoreactivity. In addition to this catecholamine-enkephalin cell population, a moderate number of substance P-immunoreactive cell bodies was found in dorsolateral pons. The peribrachial nuclei were found to be densely supplied with substance P- and enkephalin-immunoreactive fibers, whereas the medial subdivisions, which contain the majority of the catecholamine cells in the dorsolateral pons, display a moderate number of immunoreactive fibers. These results are suggestive of interactions between peptide-containing and catecholaminergic neurons and also between-peptide-containing and non-catecholamine-containing neurons in the cat dorsolateral pons. 相似文献
1000.
Preferential apoptosis of CD56dim natural killer cell subset in patients with cancer 总被引:5,自引:0,他引:5
Bauernhofer T Kuss I Henderson B Baum AS Whiteside TL 《European journal of immunology》2003,33(1):119-124
Natural killer (NK) cells (CD56(+)/CD3(-)) in the circulation of cancer patients were reported to have low NK activity and undergo spontaneous apoptosis. A possible relationship between apoptosis and impaired NK activity was studied by Annexin V-binding and NK-cell assays performed with peripheral blood mononuclear cells of patients with head and neck cancer (HNC), breast cancer (BC) and normal controls (NC). Cells stained with Annexin V (Anx) and antibodies to CD56, CD3, CD95, CD25, CD122 or CD132 were examined by flow cytometry. NK activity was tested against K562 targets in 4-h (51)Cr-release assays. The ratio of CD56(dim)/CD56(bright) NK cells was significantly different in patients vs. controls (10 vs. 16; p<0.01). A significantly greater percentage of CD56(dim) NK cells bound Anx in HNC patients (27+/-17%, median +/- SD) or BC (46+/-18%) than in NC (15+/-18%, p<0.04 and p<0.0002, respectively). CD56(dim) NK cells were preferentially targeted for apoptosis. NK activity was significantly lower in patients with HNC and BC than in NC (p<0.009). An inverse correlation between NK activity and the percent of Anx(+)CD56(dim) NK cells was observed in cancer patients (p =0.002) but not in NC. In patients, circulating CD56(dim) NK cells were targeted for apoptosis, leading to low levels of NK activity. 相似文献