全文获取类型
收费全文 | 3773篇 |
免费 | 243篇 |
国内免费 | 102篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 96篇 |
妇产科学 | 137篇 |
基础医学 | 614篇 |
口腔科学 | 33篇 |
临床医学 | 397篇 |
内科学 | 487篇 |
皮肤病学 | 51篇 |
神经病学 | 399篇 |
特种医学 | 65篇 |
外国民族医学 | 1篇 |
外科学 | 208篇 |
综合类 | 473篇 |
预防医学 | 248篇 |
眼科学 | 17篇 |
药学 | 554篇 |
2篇 | |
中国医学 | 78篇 |
肿瘤学 | 244篇 |
出版年
2023年 | 43篇 |
2022年 | 65篇 |
2021年 | 107篇 |
2020年 | 101篇 |
2019年 | 108篇 |
2018年 | 121篇 |
2017年 | 111篇 |
2016年 | 106篇 |
2015年 | 111篇 |
2014年 | 218篇 |
2013年 | 229篇 |
2012年 | 219篇 |
2011年 | 256篇 |
2010年 | 188篇 |
2009年 | 196篇 |
2008年 | 179篇 |
2007年 | 177篇 |
2006年 | 148篇 |
2005年 | 138篇 |
2004年 | 124篇 |
2003年 | 118篇 |
2002年 | 87篇 |
2001年 | 78篇 |
2000年 | 106篇 |
1999年 | 87篇 |
1998年 | 75篇 |
1997年 | 68篇 |
1996年 | 71篇 |
1995年 | 54篇 |
1994年 | 38篇 |
1993年 | 41篇 |
1992年 | 23篇 |
1991年 | 23篇 |
1990年 | 21篇 |
1989年 | 15篇 |
1987年 | 10篇 |
1986年 | 12篇 |
1985年 | 35篇 |
1984年 | 24篇 |
1983年 | 24篇 |
1982年 | 24篇 |
1981年 | 14篇 |
1980年 | 24篇 |
1979年 | 12篇 |
1978年 | 11篇 |
1977年 | 13篇 |
1976年 | 16篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1973年 | 11篇 |
排序方式: 共有4118条查询结果,搜索用时 62 毫秒
11.
负载异体抗原对低剂量粒细胞巨噬细胞集落刺激因子诱导的树突状细胞免疫学性状的影响 总被引:1,自引:1,他引:0
目的观察低剂量粒细胞巨噬细胞集落刺激因子(GM-CSF)诱生的未成熟树突状细胞(GM~(low)DC)对异体抗原的摄取能力,以及负载异体抗原后细胞表型和功能的改变。方法对处于增殖期的C_(57)BL/6小鼠单个核细胞(MNC)作氚标记亮氨酸(~3H-Leu)掺入处理,制备~3H-Leu标记的抗原上清液。将此抗原上清液分别与昆明小鼠GM~(low)DC和成熟树突状细胞(DC)孵育30、60、90 min,检测细胞每分钟放射性荧光闪烁计数(cpm)值;用流式细胞仪检测负载异体抗原前后GM~(low)DC表面I~A/I~E、CD80分子的表达情况。分离C_(57)BL/6小鼠的T淋巴细胞,根据加入的刺激因素分组并进行同种混合淋巴细胞反应(MLR):对照组(不加刺激因素)、GM~(low)DC组、GM~(low)DC+异体抗原组、GM~(low)DC+异体抗原+细胞毒性T淋巴细胞相关抗原4Ig(CTLA-4Ig)组。检测各组细胞cpm值,计算刺激指数(SI)。结果加入异体抗原上清液后30、60、90 min,GM~(low)DC的cpm值均明显高于同时相点的成熟DC(P<0.05或0.01)。负载异体抗原前,GM~(low)DC细胞表面I~A/I~E的表达率为(32±8)%,CD80的表达率为(25±10)%;负载后两者分别为(54±10)%、(71±18)%,均明显升高(P<0.05或0.01)。MLR:GM~(low)DC+异体抗原组细胞cpm值明显高于对照组(P<0.05),SI>2.0;GM~(low)DC组以及GM~(low)DC+异体抗原+CTLA-4Ig组细胞cpm值与对照组比较,差异无统计学意义(P>0.05),AI均<2.0。结论GM~(low)DC具有较强的抗原摄取能力,负载抗原后,细胞在表型及功能上渐趋成熟。应用CTLA-4Ig可阻断其免疫应答效应,建立免疫耐受。 相似文献
12.
13.
14.
骨质疏松症(OP)是严重威胁老年人身心健康的常见疾病。随着人口老年化,老年性骨质疏松症发病率逐年增加。近年来内分泌性骨质疏松日见增多,促甲状腺激素(TSH)及促甲状腺激素受体(TSHR)与骨量减少、骨质疏松的关系倍受关注。成骨细胞和破骨细胞上的促甲状腺激素受体的作用是造成这一作用的关键。而此过程还会受到2型碘化甲腺氨酸脱碘酶、肿瘤坏死因子(TNF)等的影响。同时促甲状腺激素受体存在基因多态性,对其功能存在不同程度的影响,也可能是造成骨质疏松的重要原因。通过对这个领域的深入研究为内分泌性骨质疏松的防治提供依据。 相似文献
15.
Rob Cincotta Alan Balloch Jack Metz Judith E. Layton Graham J. Lieschke 《American journal of hematology》1995,48(4):288-288
A patient with neutropenia and life-threatening infections secondary to T-γ lymphoproliferative disease, who did not respond to treatment with recombinant human G-CSF (filgrastim), was treated with filgrastim plus cyclosporine A (CyA). The patient achieved a good response in the absolute neutrophil count and subsequently required a dose reduction in the filgrastim. The patient was eventually discontinued from the CyA but continues on filgrastim alone. While on therapy, the large granular lymphocytes disappeared from the circulation and the beta-TCR rearrangement, which was present prior to beginning therapy, became undetectable. The patient had no significant toxicity to the CyA or the filgrastim and he has not experienced any serious infections or required hospitalization. Filgrastim has proven to be relatively nontoxic and of some benefit to patients with this disease and should probably be utilized first when treatment is necessary. However, if improvement is not observed, these findings suggest that a trial of the combination of CyA plus filgrastim may be beneficial. 相似文献
16.
Josefa Vega-Matuszczyk Viveka Hillegaart Knut Larsson Sven Ahlenius 《Brain research》1993,630(1-2):82-87
Regional changes in the rate of brain monoamine synthesis were monitored in male rats exposed to, but prevented from physical contact with, an estrous or an ovariectomized female. The in vivo rate of tyrosine and tryptophan hydroxylase activities were estimated by measuring the accumulation of DOPA and 5-HTP following inhibition of cerebral aromatic l-amino acid decarboxylase by means of 3-hydroxybenzylhydrazine (NSD-1015) treatment (100 mg/kg i.p.) 5 min upon NSD-1015 treatment, the males were exposed to an intact estrous female or an ovariectomized female for 20 min before decapitation and brain dissections. Exposure to an estrous female produced an increased rate of tyrosine and tryptophan hydroxylase activity in the medial prefrontal cortex, the dorso-lateral neostriatum and in the ventral neostriatum, in comparison with home-cage controls. By the same comparison, exposure to an ovariectomized female resulted in an increased rate of tyrosine hydroxylase activity in the medial prefrontal cortex, byt not in the neostriatal areas, whereas tryptophan hydroxylase activity was unaffected. Finally, exposure to the empty test cage, with no stimulus females present, did not produce any statistically significant changes in the rate of tyrosine or tryptophan hydroxylase activity in any of the brain areas sampled. Taken together with recent findings from this laboratory, the present results demonstrate that the level of sexual motivation brought about by the olfactory, auditory and/or visual stimulation of a receptive female is associated with an increased demand on catecholamine and 5-hydroxytryptamine synthesis in the limbic forebrain of the male rat. The finding that the presence of an unestrous female produced an enhanced demand on tyrosine hydroxylase activity in the medial prefrontal neocortex demonstrates that the sexual incentive provided by the estrous female may not be the only factor responsible for all the effects observed in the present study. In fact, there is a distinct possibility that the intense challenge produced by sexually significant stimuli is but an endpoint, and that the changes found in forebrain monoamine synthesis is a reflection of an environmental challenge not necessarily specifically linked to the sexual behavior. 相似文献
17.
LEMAN YEL ILHAN TEZCAN
ZDEN SANAL FÜGEN ERSOY A IZZET BERKEL 《Pediatrics international》1996,38(3):288-290
A 3.5 year old male patient with dyskeratosis congenita (DC) presented at the age of 13 months with isolated neutropenia preceding characteristic skin findings. The average absolute neutrophil count of 500/mm3 persisted without the presence of anemia or thrombocytopenia during the follow up. Neutropenia responded to granulocyte-colony stimulating factor (G-CSF) at a dose of 10 μg/kg per day. Immunologic findings were normal as was the chromosomal stability and sister chromatid exchange. 相似文献
18.
目的 研究多发创伤患者早期血清促卵泡生成素(FSH)、促黄体生成素(LH)变化与创伤严重度和格拉斯哥昏迷评分的关系.方法 随机选取2003年3月~2004年2月急诊就诊的多发创伤患者93例,就诊时间均在伤后24h内,即时采集血样,采用放射免疫双抗体沉淀法测定血清FSH、LH水平,并另选20名健康体检者作为对照组.93例患者按照ISS评分予以分组(ISS<16分47例,25≥ISS≥16分24例,ISS>25分22例),其中合并颅脑损伤者按GCS评分分组ISS<16分14例,25≥ISS≥16分14例,ISS>25分12例,并比较各分组间FSH、LH水平.结果 严重创伤组(ISS>25分)与合并颅脑损伤组患者早期FSH、LH明显升高(P<0.01).ISS>25分组、25≥ISS≥16分组、ISS<16分组血清FSH、LH水平依次降低(P<0.05或0.01),且前2组明显高于对照组(P<0.01).合并颅脑损伤者中,GCS>8分组、8≥GCS>5分组、5≥GCS≥3分组血清FSH、LH水平依次降低,组间比较差异有显著性(P<0.05或0.01),且均显著高于对照组(P<0.05或0.01).结论 血清垂体前叶激素FSH、LH水平的改变与严重创伤、颅脑损伤的严重程度相关,可作为判断伤情、观察预后的参考指标. 相似文献
19.
目的:利用粒细胞-巨噬细胞集落刺激因子(GM-CSF)作为基因佐剂,提高东部马脑炎病毒E2基因重组质粒的免疫效果.方法:分别扩增E2基因与GM-CSF基因,连接进入含有内部核糖体插入位点(IRES)的真核表达载体中,构建共表达质粒.Lipofectamine2000介导转染真核细胞BHK-21,反转录PCR检测E2和GM-CSF两个基因的转录,Western印迹法和间接免疫荧光法(IFA)检测细胞内E2基因表达产物的抗原性.通过肌肉注射免疫BALB/c小鼠,IFA法测定血清抗体效价,FACS测定免疫小鼠脾细胞中CD4 /CD8 淋巴细胞构成比,初步观察共表达质粒的免疫原性.结果:经酶切鉴定与序列测定证明重组共表达质粒中含有E2和GM-CSF两个基因且序列正确.转染细胞的反转录PCR可见E2和GM-CSF两个基因的转录.Western印迹结果可见转染细胞的裂解液在相对分子质量50 000位置有特异性条带.将转染细胞制成荧光抗原片,经IFA检测可见胞浆中出现特异荧光.免疫小鼠的最高血清抗体效价为1:160,但细胞免疫未观察到明显的提高.结论:构建的共表达质粒pE2-IRES-mGM-CSF具有良好的免疫原性,能有效刺激小鼠特异性体液免疫应答,提高了E2基因重组质粒诱导的血清抗体效价. 相似文献
20.
Granulocyte-macrophage colony stimulating factor (GM-CSF) modulates various functions of monocytes/ macrophages including antigen-presenting capacity. Recently it was found that astrocytes produce GM-CSF in the central nervous system (CNS) and that GM-CSF can induce proliferation and morphological changes of microglia. Here we show that GM-CSF can down regulate the interferon-γ-mediated induction of major histocompatibility complex (MHC) class II antigens in microglia, but not in astrocytes. GM-CSF pretreatment completely prevents myelin basic protein-specific T cell proliferation induced by microglia but not astrocytes. GM-CSF did not affect the cell surface expression on microglia of either MHC class I or cell adhesion molecules. The inhibition of microglial MHC class II expression and antigen-presenting function is specific for GM-CSF, as treatment with a different CSF (interleukin-3) did not modulate microglial phenotype or functional capacity. These data suggest that GM-CSF might be involved in the regulation of immune responses within the central nervous system. 相似文献