全文获取类型
收费全文 | 2531篇 |
免费 | 127篇 |
国内免费 | 64篇 |
专业分类
耳鼻咽喉 | 26篇 |
儿科学 | 81篇 |
妇产科学 | 35篇 |
基础医学 | 583篇 |
口腔科学 | 9篇 |
临床医学 | 198篇 |
内科学 | 324篇 |
皮肤病学 | 63篇 |
神经病学 | 131篇 |
特种医学 | 52篇 |
外科学 | 156篇 |
综合类 | 395篇 |
预防医学 | 191篇 |
眼科学 | 7篇 |
药学 | 231篇 |
中国医学 | 78篇 |
肿瘤学 | 162篇 |
出版年
2023年 | 14篇 |
2022年 | 34篇 |
2021年 | 47篇 |
2020年 | 65篇 |
2019年 | 43篇 |
2018年 | 34篇 |
2017年 | 35篇 |
2016年 | 56篇 |
2015年 | 50篇 |
2014年 | 79篇 |
2013年 | 113篇 |
2012年 | 88篇 |
2011年 | 119篇 |
2010年 | 94篇 |
2009年 | 107篇 |
2008年 | 101篇 |
2007年 | 120篇 |
2006年 | 100篇 |
2005年 | 113篇 |
2004年 | 98篇 |
2003年 | 120篇 |
2002年 | 73篇 |
2001年 | 84篇 |
2000年 | 84篇 |
1999年 | 57篇 |
1998年 | 71篇 |
1997年 | 82篇 |
1996年 | 60篇 |
1995年 | 73篇 |
1994年 | 73篇 |
1993年 | 40篇 |
1992年 | 47篇 |
1991年 | 52篇 |
1990年 | 41篇 |
1989年 | 36篇 |
1988年 | 24篇 |
1987年 | 25篇 |
1986年 | 21篇 |
1985年 | 31篇 |
1984年 | 33篇 |
1983年 | 13篇 |
1982年 | 17篇 |
1981年 | 10篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1978年 | 2篇 |
1977年 | 11篇 |
1975年 | 3篇 |
1971年 | 2篇 |
1906年 | 1篇 |
排序方式: 共有2722条查询结果,搜索用时 15 毫秒
41.
淋巴细胞经TCR-CD3活化增殖作用的分析 总被引:1,自引:0,他引:1
本文探讨了抗CD3单抗诱导的淋巴细胞活化增殖及有关影响因素。实验结果表明:①淋巴细胞内钙升高是淋巴细胞活化增殖的重要条件,CD3McAb引起的早期胞浆游离钙迅速升高主要由内质网释放钙离子所致,而淋巴细胞增殖不仅需要细胞内钙释放,还需要细胞外钙内流;②GTP结合蛋白是淋巴细胞激活过程的一重要环节,经G蛋白作用物霍乱毒素作用后,淋巴细胞DNA合成显著降低;③新霉素和PSS可抑制PLC和PkC的活性,对淋巴细胞NDA合成造成剂量依赖性抑制作用。此外,抗CD3McAb诱导的淋巴细胞DNA合成需要辅佐细胞的存在,高度纯化的T细胞对CD3McAb的刺激不发生增殖反应。 相似文献
42.
Russell JH 《Immunologic research》2005,32(1-3):225-229
Much of the understanding of tolerance has focused on the requirements for antigen-specific lymphocyte activation and function.
However, there is increasing evidence for anatomic regulation of effector access to self antigens. Recently, a number of studies
have provided evidence for tissue-specific “addressins” in chemokine/chemokine receptor pairs. The central nervous system
(CNS) provides special anatomic barriers to the movement of cells from the vascular compartment to the parenchyma. Herein
I raise the possibility that antigen, perhaps through specialized antigen-presenting cells, may play a role in regulating
access of activated lymphocytes into the CNS parenchyma. The results suggest that a reexamination of the widely held dogma
that all activated lymphocytes have access to the CNS parenchyma is nessary to understand the relationship between the immune
and central nervous systems. 相似文献
43.
The effect of the growth state of a cell on the ability of hyperthermia to induce the synthesis of heat shock proteins (HSPs) was studied in resting and concanavalin A (ConA)-stimulated lymphocytes. Hyperthermia induced the synthesis of hsp 110, hsp 90, hsc 70, and hsp 70 in both resting and ConA-stimulated lymhocytes, and ConA-treatment induced the synthesis of the hsp 90 and hsc 70 at normal temperature. The induction of the synthesis of hsp 110 and hsp 70 by hyperthermia was 3- to 6-fold higher for lymphocytes cultured with ConA for 12 and 24 h than in non-stimulated lymphocytes. Thus, lymphocytes induced to undergo proliferation showed a greater response to hyperthermia than resting lymphocytes. 相似文献
44.
ADA活性紫外吸收测定法的改良及复感儿淋巴细胞该酶活性的检测 总被引:2,自引:0,他引:2
检测了42例健康儿童和17例反复上呼吸道感染患儿(复感儿)的血淋巴细胞腺苷脱氨酶(ADA)活性,结果表明:复感儿的血淋巴细胞中ADA活性较健康儿童低下,且大多同样伴有不同程度的免疫功能低下;从复感儿组中筛选了两侧ADA活性和免疫功能明显低下的患儿,拟采用这两例患儿的血淋巴细胞进行ADA-SCID基因治疗的实验研究。 相似文献
45.
H. -O. Wintzer R. Amberg S. von Kleist B. Forster 《Virchows Archiv : an international journal of pathology》1988,413(6):581-589
Summary The postmortem stability of cell antigens has hardly been studied. Using monoclonal antibodies (mabs) we examined the postmortem detectability of lymphocyte surface antigens in different lymphoid organs by comparing two sensitive, immunohistological staining procedures.To quantify the probable degree of autolysis of the tissues a score system was applied by taking into consideration the postmortem age as well as the core temperature of the corpses.The antigens examined generally proved to be very resistant to autolytic influences. Differences were found when comparing different mabs and with regard to the type of lymphoid tissue. The loss of immunohistological reactions was most extensive in the spleen whereas tonsils showed almost no qualitative alterations in staining patterns. Reactivity of mabs with postmortem tissues decreased in the following order: Dako CD22 and anti-Leu 4, anti-Leu 3a, anti-Leu 7, Dako T8. The mabs anti-Leu 7 and Dako-T8 frequently failed to demonstrate their respective antigens but no correlation between the loss of staining and the degree of autolytic decomposition (our score) could be detected.In general, postmortem tissues as well as tissues shock frozen after delay are suitable for qualitative immunohistology of those cells characterized by the mabs applied.The APAAP-method proved unequivocally to be the superior staining technique. 相似文献
46.
47.
Poapolathep A Nagata T Suzuki H Kumagai S Doi K 《Experimental and molecular pathology》2003,75(1):74-79
Development of early apoptosis and changes in lymphocyte subsets were examined in lymphoid organs of female BALB/c mice after oral administration of 15 mg/kg b.w. of nivalenol (NIV), the major type B trichothecene mycotoxin, by FACS analysis. Judging from the results of viable cell count and apoptotic cell index, NIV attacked Peyer's patches first and thymus most severely. In thymus, selective damage in CD4(+)CD8(+) cells was observed at 12 and 24 h after inoculation (HAI), following the peak of apoptosis at 9 HAI. CD4(+) cells were clearly suppressed at 3 HAI in Peyer's patches, at and after 9 HAI in mesenteric lymph nodes, and 3 to 12 HAI in spleen, respectively. CD8(+) cells were also suppressed at 24 HAI in mesenteric lymph nodes and at 12 HAI in spleen, respectively. As to changes in B cell subsets, IgG(+) cells significantly decreased from 3 to 12 HAI and all B cell subsets at 24 HAI in mesenteric lymph nodes. In spleen, IgM(+) cells were suppressed at 9 HAI. On the other hand, in Peyer's patches, following clear decrease in the numbers of pan-T and pan-B cells and viable cells at 3 HAI, all B cell subsets, especially IgA(+) cells, showed a significant increase in their numbers at 9 HAI, and the numbers of IgA(+) and IgM(+) cells remained higher values than controls thereafter. Taken together, in the course of recovery from NIV-induced prominent damage in Peyer's patches at 3 HAI, interaction of NIV with Peyer's patches might result in in vivo stimulation of interleukin production at this site and result in increased proliferation and differentiation of IgA-secreting B cells at and after 9 HAI. 相似文献
48.
Sanna Toppila Jouni Lauronen Pirkko Mattila Juha Pekka Turunen Leena Penttil Timo Paavonen Ossi Renkonen Risto Renkonen 《European journal of immunology》1997,27(6):1360-1365
Lymphocyte homing is initiated by their tethering to and rolling on the high endothelium and is followed by extravasation into the lymph nodes. We show here that glycosylated cell adhesion molecule-1 (GlyCAM-1), CD34, and sialyl Lewis x (sLex) are present on rat lymph node high endothelium analyzed by using monoclonal antibodies. α(1,3)fucosyltransferase VII (Fuc-TVII), the last enzyme involved in the synthesis of the sLex sequence is also expressed on the rat lymph node high endothelium. We have synthesized a family of sLex-decorated oligosaccharide structures and used them to inhibit lymphocyte binding to high endothelium in the Stamper-Woodruff assay. Monovalent sLex, branched di- and tetravalent sLex, as well as a linear tetravalent sLex significantly reduce lymphocyte binding to endothelium. The branched and linear forms of tetravalent sLex were clearly superior inhibitors of the L-selectin-dependent lymphocyte adhesion, with IC50 values in low nanomolar range. In contrast, the fucose-free analogs having the same charge and approximately the same size as the corresponding sLex glycans had no effect on lymphocyte binding and served as negative controls. Taken together, these data show the crucial importance of sLex in the endothelial ligands for L-selectin. Furthermore, we suggest that L-selectin acts as an oligomer on the lymphocyte surface as it binds multivalent sLex glycans. 相似文献
49.
50.
NOD鼠胸腺及外周淋巴细胞亚群变化与年龄关系 总被引:1,自引:0,他引:1
NOD鼠可自发地患糖尿病,该鼠的发病与自身免疫性淋巴细胞对胰岛的浸润,从而引起胰岛β细胞的不断破坏有关。这种破坏可能是由T淋巴细胞所引起的。雌性NOD鼠胸腺及外周淋巴细胞随年龄的增加胸腺细胞数量减少而脾细胞数量增加。用CD4/CD8双抗双标检测显示,雌性NOD糖尿病鼠胸腺双阴性与单阳性细胞的比例增加而双阳性细胞的比例减少。外周CD4比CD8阳性细胞的比值在胰岛炎期增高,在糖尿病期下降。 相似文献