全文获取类型
收费全文 | 10427篇 |
免费 | 824篇 |
国内免费 | 334篇 |
专业分类
耳鼻咽喉 | 76篇 |
儿科学 | 213篇 |
妇产科学 | 125篇 |
基础医学 | 2265篇 |
口腔科学 | 55篇 |
临床医学 | 632篇 |
内科学 | 1550篇 |
皮肤病学 | 129篇 |
神经病学 | 406篇 |
特种医学 | 148篇 |
外科学 | 820篇 |
综合类 | 1424篇 |
预防医学 | 1178篇 |
眼科学 | 64篇 |
药学 | 851篇 |
7篇 | |
中国医学 | 594篇 |
肿瘤学 | 1048篇 |
出版年
2024年 | 40篇 |
2023年 | 282篇 |
2022年 | 532篇 |
2021年 | 663篇 |
2020年 | 629篇 |
2019年 | 390篇 |
2018年 | 340篇 |
2017年 | 484篇 |
2016年 | 437篇 |
2015年 | 509篇 |
2014年 | 714篇 |
2013年 | 585篇 |
2012年 | 599篇 |
2011年 | 740篇 |
2010年 | 446篇 |
2009年 | 390篇 |
2008年 | 411篇 |
2007年 | 436篇 |
2006年 | 415篇 |
2005年 | 311篇 |
2004年 | 247篇 |
2003年 | 280篇 |
2002年 | 193篇 |
2001年 | 168篇 |
2000年 | 148篇 |
1999年 | 141篇 |
1998年 | 101篇 |
1997年 | 105篇 |
1996年 | 97篇 |
1995年 | 77篇 |
1994年 | 96篇 |
1993年 | 58篇 |
1992年 | 51篇 |
1991年 | 54篇 |
1990年 | 45篇 |
1989年 | 51篇 |
1988年 | 53篇 |
1987年 | 31篇 |
1986年 | 31篇 |
1985年 | 34篇 |
1984年 | 41篇 |
1983年 | 15篇 |
1982年 | 29篇 |
1981年 | 19篇 |
1980年 | 17篇 |
1979年 | 15篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1976年 | 8篇 |
1971年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
B. T. Nasah Dr. J. N. Cox 《Virchows Archiv : an international journal of pathology》1978,377(3):225-236
Summary Testicular biopsies in 40 of 41 infertile males with severe oligospermia in Cameroon presented massive subendothelial fibrinoid deposits in the small and medium sized vessels. Fibrinogen, complement and IgM were demonstrated in these deposits by immunofluorescence. Evidence strongly suggestive of parasitic testicular involvement was also observed in 2 cases.It is postulated that the fibrinoid deposits are the result of repeated formation and deposition of circulating immune complexes by reaction of antibodies with antigens. These antigens could be of various origins and in the cases described here they could be derived from living or dying parasites in the region. The accumulation and incorporation of the fibrinoid deposits may lead to vascular stenosis resulting in chronic ischaemia, tubular atrophy and fibrosis, and finally oligospermia. 相似文献
32.
Circulating leucocyte subpopulations in sedentary subjects following graded maximal exercise with hypoxia 总被引:4,自引:0,他引:4
Holger Gabriel Thomas Kullmer Lothar Schwarz Axel Urhausen Benno Weiler Petra Born Wilfried Kindermann 《European journal of applied physiology》1993,67(4):348-353
Summary Ten healthy sedentary subjects [age, 27.5 (SD 3.5) years; height, 180 (SD 5) cm; mass, 69.3 (SD 6.3) kg] performed two periods of maximal incremental graded cycle ergometer exercise in a supine position. Randomly ordered and using an open spirometric system, one exercise was carried out during normoxia [maximal oxygen consumption (
O2max)=38.6 (SD 3.5) ml·min–1·kg–1; maximal blood lactate concentration, 9.86 (SD 1.85) mmol·l–1; test duration, 22.6 (SD 2.7) min], the other during hypoxia [
O2max=33.2 (SD 3.2) ml·min–1· kg–1; maximal blood lactate concentration, 10.38 (SD 2.02) mmol·l–1; test duration, 19.7 (SD 2.8) min]. At rest, immediately (0 p) and 60 min (60 p) after exercise, counts of leucocyte subpopulations (flow cytometry), cortisol and catecholamine concentrations were determined. At 0 p in contrast to normoxia, during hypoxia there was no significant increase of granulocytes. There were no significant differences between normoxia and hypoxia in the increases from rest to 0 p in counts of monocytes, total lymphocytes and lymphocyte subpopulations [clusters of differentiation (CD), CD3+, CD4+CD45RO–, CD4+CD45RO+, CD8+CD45RO–, CD8+CD45RO+, CD3+HLA-DR+, CD3–CD16/CD56+, CD3+CD16/CD56+, CD 19+] as well as adrenaline, noradrenaline and cortisol concentrations. The counts of CD3 –CD16/CD56+-and CD8 +CD45RO+-cells increased most. At 60 p, CD3–CD16/CD56+ and CD3+CD16/CD56+-cell counts were below pre-exercise levels and under hypoxia slightly but significantly lower than under normoxia. We concluded that the exercise-induced mobilization and redistribution of most leucocyte and lymphocyte subpopulations were unimpaired under acute hypoxia at sea level. Reduced increases of granulocyte counts during the study and reduced cell numbers of natural killer cells and cytotoxic, not major histocompatibility complex-restricted T-cells, only indicated marginal effects on the immune system. 相似文献
33.
用BA-ELISA斑点法检测痢疾杆菌免疫小鼠GALT中的特异性抗体分泌细胞(ASC) 总被引:1,自引:0,他引:1
改进的BA-ELISPOT法使免疫酶斑更为清晰,保存时间延长。用此法检测了痢疾杆菌福氏2a经口及腹腔免疫后,小鼠派伊尔氏(PP)淋巴结、肠系膜淋巴结(MLN)及脾脏(SPL)中特异性IgA、IgG、IgM抗体分泌细胞(AntibodySecretingcell,ASC)的动态变化,得到有规律的结果:两种免疫途径均能在PP及MLN中诱导出3类特异ASC的显著升高,但口服导致的升高其持续时间较腹腔途径为短。此外,腹腔途径还能诱导SPL中3种ASC升高。 相似文献
34.
目的 探索“细胞 +环磷酰胺 (cyclophosphamide ,CP)”系统联合抗H 2 b 单克隆抗体、供体骨髓细胞输注诱导移植耐受的作用及其机制。方法 第 0天 ,经尾静脉给C5 7BL/ 6 (H 2 b,B6 )小鼠注入 10 8BALB/c(H 2 d,B/c)来源的脾细胞 ,第 2天 ,腹腔注射环磷酰胺 2 0 0mg/kg ,第 3、5天 ,分别经尾静脉注入抗H 2 b 单抗 ,剂量为 40 0 μg/ 0 .5ml,第 8天进行皮肤移植。皮肤移植后 1周 (第 15天 ) ,输入 2× 10 7供体BALB/c来源的骨髓细胞。观察皮肤移植物存活时间 ,并于第 30天对耐受B6小鼠作混合淋巴细胞反应 (mixedlymphocytereaction ,MLR) ,迟发型超敏反应 (delayedtypehypersensitivity ,DTH)等确定耐受的状态。并通过过继转移实验、嵌合体检查及脾细胞中细胞因子mRNA的表达情况 ,进一步探讨耐受形成的机制。结果 采用此诱导方案 ,B6小鼠对BALB/c小鼠的皮肤移植物长期存活。耐受可以被过继转移 ;耐受小鼠胸腺内的嵌合程度与耐受的维持密切相关 ;TH1型细胞因子在耐受小鼠中明显降低 ,而TH2型细胞因子明显升高。结论 “细胞 +CP”系统联合H 2 b 单克隆抗体、供体骨髓细胞输注能够诱导异基因小鼠皮肤移植耐受。耐受机制与胸腺嵌合体的存在密切相关。克隆无能 (aner gy)、抑制细胞和TH1/TH2偏移在耐受中也 相似文献
35.
目的探讨Fas在正常妊娠过程及妊娠期高血压疾病(HDCP)中的表达变化及意义。方法分别选取正常妊娠早期和晚期及HDCP胎盘绒毛组织。采用免疫组织化学方法检测Fas表达,并用高清晰彩色病理图像分析系统对其表达进行分析。结果Fas在妊娠早期胎盘组织中极少表达,妊娠晚期胎盘组织中表达增高。HDCP胎盘组织中Fas表达明显升高,与前两组比较差异有极显著性(P<0.01)。结论孕早期滋养细胞表面Fas表达在母胎免疫耐受中发挥重要作用,孕晚期Fas表达增加可能是引起HDCP的原因之一。 相似文献
36.
目的比较腺病毒载体(Ad)介导人和小鼠酪氨酸酶相关蛋白2(tyrosinase-relatedpro-tein2,TRP2)修饰小鼠骨髓来源的树突状细胞(BM-DC)诱发抗小鼠黑色素瘤免疫的差异。方法Ad编码人或小鼠TRP2(AdhTRP2或AdmTRP2)体外感染小鼠BM-DC并体内皮下免疫C57BL/6小鼠,7d后取出被免疫小鼠脾细胞行体内细胞毒性T淋巴细胞杀伤试验(invivoCTL)和细胞内IFN-γ染色(ICS)分析CTL的杀伤活性和IFN-γ的产生;或给免疫后小鼠皮下接种小鼠B16.F10黑色素瘤细胞,观察荷瘤小鼠的成活情况。结果invivoCTL和ICS分析显示,AdhTRP2/BM-DC免疫小鼠,其6hCTL杀伤率为(98.7±1.2)%,IFN-γ产生的CD8+T细胞占总CD8+T细胞的(1.25±0.21)%;而AdmTRP2/BM-DC免疫的小鼠,其6hCTL杀伤率和产生IFN-γ的CD8+T细胞比例分别为(28.6±6.3)%和(0.24±0.06)%。荷瘤试验表明,AdhTRP2/BM-DC免疫小鼠后1周皮下接种106B16.F10细胞,观察3个月100%的小鼠无瘤生长;而接种5×104B16.F10细胞至AdmTRP2/BM-DC免疫1周的小鼠,3个月后小鼠成活率仅为40%。结论Ad介导异种(人)TRP2较自身(小鼠)TRP2修饰的BM-DC更为有效地打破肿瘤免疫耐受、诱导强烈的抗黑色素瘤免疫反应,是一种高效的以DC为基础的肿瘤疫苗。 相似文献
37.
Pisetsky DS 《Immunologic research》2000,22(2-3):119-126
Because of structural microheterogeneity, DNA can exert powerful effects that lead to immune system activation as well as
antibody induction. These activating effects resemble those of endotoxin and result from sequences that occur much more commonly
in bacterial DNA than in mammalian DNA. In contrast, mammalian DNA can inhibit the response to bacterial DNA as well as other
stimuli and may serve a counterregulatory role during infection. The recognition of the immune effects of DNA is relevant
to the pathogenesis of a variety of infectious and inflammatory diseases including systemic lupus erythematosus, a prototypic
autoimmune disease characterized by anti-DNA autoantibodies. 相似文献
38.
Richard Meehan Ulric Duncan Laureen Neale Gerald Taylor Harold Muchmore Nan Scott Keith Ramsey Eric Smith Paul Rock Randall Goldblum Charles Houston 《Journal of clinical immunology》1988,8(5):397-406
We investigated the effects on immune function after progressive hypobaric hypoxia simulating an ascent to 25,000 ft (7620 m) over 4 weeks. Multiple simultaneousin vitro andin vivo immunologic variables were obtained from subjects at sea level, 7500 ft (2286 m), and 25,000 ft during a decompression chamber exposure. Phytohemag-glutinin-stimulated thymidine uptake and protein synthesis in mononuclear cells were reduced at extreme altitudes. Mononuclear-cell subset analysis by flow cytometry disclosed an increase in monocytes without changes in B cells or T-cell subsets. Plasma IgM and IgA but not IgG levels were increased at altitudes, whereas pokeweed mitogen-stimulatedin vitro IgG, IgA, and IgM secretion was unchanged. During exposure to 25,000 ft,in vitro phytohemagglutinin-stimulated interferon production and natural killer-cell cytotoxicity did not change statistically, but larger intersubject differences occurred. IgA and lysozyme levels (nasal wash) and serum antibodies to nuclear antigens were not influenced by altitude exposure. These results suggest that T-cell activation is blunted during exposure to severe hypoxemia, whereas B-cell function and mucosal immunity are not. Although the mechanism of alteredin vitro immune responsiveness after exposure to various environmental stressors has not been elucidated in humans, hypoxia may induce alterations in immune regulation as suggested byin vitro immune assays of effector-cell function.Some of this study's results were presented as an abstract at the FASEB meeting in St. Louis, Missouri, 1986. 相似文献
39.
本文报道了30例食管癌、20例胃癌、15例乳腺癌、8例肝癌、10例淋巴瘤等患者红细胞免疫粘附功能的初步结果,并与67例献血员值进行了比较。几种肿瘤病人的RBC C_(3b)RR低下,RBC-ICR较高,两者与献血员值比较都有明显差别(P<0.01),几种肿瘤患者CIC阳性率在60~83.4%之间。对食管癌患者部分病例进行跟踪检测,并对其临床意义进行了初步探讨。 相似文献
40.
Toll样受体(TLR)在介导固有免疫和适应性免疫应答中有重要作用,可以表达于多种免疫细胞,包括树突状细胞(DC).了解Toll样受体的免疫学基础、与DC之间的联系以及其在免疫耐受干预方面的作用很有必要. 相似文献