全文获取类型
收费全文 | 2545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 | 585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 | 165篇 |
综合类 | 395篇 |
预防医学 | 192篇 |
眼科学 | 7篇 |
药学 | 231篇 |
中国医学 | 78篇 |
肿瘤学 | 164篇 |
出版年
2023年 | 17篇 |
2022年 | 38篇 |
2021年 | 48篇 |
2020年 | 68篇 |
2019年 | 43篇 |
2018年 | 35篇 |
2017年 | 36篇 |
2016年 | 56篇 |
2015年 | 51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2736条查询结果,搜索用时 15 毫秒
1.
2.
肾综合征出血热患者T细胞亚群数量与白细胞介素2,4水平变化的关系 总被引:2,自引:0,他引:2
采用ABC免疫组化染色法及单克隆抗体夹心法ELISA,同步检测了34例肾综合征出血热(HFRS)患者外周血T细胞亚群数量和血清白细胞介素2和4(IL-2、IL-4)水平。发现HFRS病程中各T细胞亚群数量均有不同程度的升高,其中CDS阳性T细胞在各病期均有升高。IL-4水平升高仅见于发热期.而IL-2的升高主要在低血压期和少尿期。病程中有CD4/CD8比值的下降甚至倒置。这种比值的变化与IL-2和IL-4的动态变化有一定的相关性。结果揭示,在HFRS发病机理中存在Thl型和Th2型免疫反应等多种免疫病理机制。 相似文献
3.
以结核菌素纯蛋白衍生物(PPD)为丝裂源作淋巴细胞转化试验,检测结核性(17例)和非结核性(14例)胸膜炎患者的外周血淋巴细胞(PBL)和胸腔积液淋巴细胞(PEL)对PPD 的反应性。结果显示:结核性胸膜炎患者无论PPD 皮试是阳性还是阴性,其PEL 的PPD 刺激指数(PPD-SI)都显著高于PBL(P 分别<0.001与<0.01);结核性PEL 的PPD-SI 显著高于非结核性PEL(P<0.001)。提示PPD 胸腔积液淋巴细胞转化试验可作为诊断结核性胸膜炎的有效方法。 相似文献
4.
Stimulation by mitogens and neuronal membranes of lymphocytes from patients with motor neurone disease 总被引:1,自引:0,他引:1
Jaqueline Aspin Roger Harrison Ahmed Jehanli George Lunt Malcolm Campbell 《Journal of neuroimmunology》1986,11(1):31-40
Stimulation of lymphocytes from motor neurone disease patients by either concanavalin A or PHA was shown to be significantly depressed relative to that from normal controls, as assayed by incorporation of [3H]thymidine or [3H]leucine or by glucose uptake. Corresponding significant differences were not shown by assays based upon incorporation of [3H]uridine or of lactate release. Lymphocytes from 4 out of 14 motor neurone disease patients showed a blastogenic response to membranes from rat spinal cord cells, compared with those from 0 out of 9 normal controls. These results not only suggest the possibility of an impaired cellular immune control in MND patients but also indicate the presence of lymphocytes sensitised specifically to neuronal membrane components. 相似文献
5.
Sebastian Walter Burkhard Micheel Reinhard Pabst Jürgen Westermann 《European journal of immunology》1995,25(5):1199-1205
Lymphocytes continuously migrate through the body, and their efficient extravasation from the blood via high endothelial venules (HEV) is essential for initiating an appropriate immune response. Most investigations have focused on the lymphocyte/HEV interaction in vitro. However, to what extent such systems reflect the situation in vivo is not known. It is also unclear whether lymphocyte subsets immigrate into the HEV in proportion to their presence in the blood, and whether import capacity is limited by the HEV. When rat mesenteric lymph node lymphocytes were incubated in vitro on cryostat sections, the well-known preferential binding of B lymphocytes to HEV of Peyer's patches (PP) and T cells to HEV of axillary lymph nodes (axLN) was observed (axLN vs. PP: B lymphocytes 21.2 ± 5.0% vs. 40.6 ± 11.0%, T lymphocytes 84.6 ± 6.3% vs. 56.5 ± 12.9%). However, when labeled mesenteric lymph node lymphocytes were injected and their location within the HEV was analyzed 15 min later, no preferential interaction was seen. After injection of labeled thoracic duct lymphocytes, the percentage of labeled cells among B and T lymphocytes in the blood was significantly different (4.4 ± 0.9% vs. 8.9 ± 3.6%), whereas that in HEV of axLN (19.0 ± 6.4% vs. 16.6 ± 6.0%) and PP (30.6 ± 6.1% vs. 33.9 ± 4.4%) was comparable. Although the number of injected lymphocytes was similar in magnitude to the total blood lymphocyte pool, after injection there was no increase in lymphocyte numbers in the HEV. Thus, the adhesion assay in vitro does not completely reflect immigration into HEV in vivo. In addition, our data suggest that both the availability of lymphocyte subsets in small venules and the immigration rate into HEV are actively regulated in vivo. 相似文献
6.
Nobutaka Eiraku Shinji Ijichi Shinji Yashiki Mitsuhiro Osame Shunro Sonoda 《Journal of neuroimmunology》1992,37(3):223-228
The in vitro proliferation of peripheral blood lymphocytes (PBLs) without any mitogenic stimulation is one of the hallmarks of human T lymphotropic virus type I (HTLV-I) infection. Recent evidence suggests a difference in the degree of the phenomenon between HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and asymptomatic HTLV-I carriers (AC). In this article, we demonstrated several alterations in the features of the in vitro transformed lymphocytes between patients with HAM/TSP (n = 16) and AC (n = 8). The percentages of total CD8+ and CD8+CD28+ cells were significantly increased in the in vitro proliferating T lymphocytes derived from the patients with HAM/TSP when compared to those from AC. HAM/TSP was segregated from AC by the high degree of the proliferation of CD8+CD28+ cells. The expression of HTLV-I-specific antigens on the cultured PBLs was detected only in the subjects which showed low CD8+CD28+/CD4+ ratio of the in vitro proliferating lymphocytes. These findings suggest that this phenomenon distinguishes HAM/TSP from AC, not only in quantity but also in quality. 相似文献
7.
高浓度吗啡对体外培养的小鼠淋巴细胞增殖的抑制效应北京医科大学药理学教研室陆正武,林志彬利用不同刺激原诱导的淋巴细胞增殖反应,研究吗啡的体外作用机制。结果表明:(1)高浓度吗啡(≥0.1mmol·L-1)以剂量依赖方式,抑制ConA/LPS所致淋巴细胞... 相似文献
8.
Eleven palatine tonsils were collected from subjects who underwent tonsillectomy in Christian Medical College Hospital and the route of migration of lymphocytes through the high endothelial vessel was studied under EM. In the interendothelial route, migration of a lymphocyte through HEV wall began with the adhesion of a lymphocyte to the surface of endothelial cells by means of a short cytoplasmic projection in the vicinity of intercellular space. The projection extended into the cleft between adjacent endothelial cells. The lymphocyte migrated through HEV by diapedesis. After the lymphocyte had traversed the interendothelial space, it occupied the subendothelial space. In the transendothelial route, migration of a lymphocyte through HEV was initiated by adherence of the lymphocyte to the endothelial cell. The adherent lymphocyte compressed or invaginated into the cytoplasm of the endothelial cell, entered the endothelial cell, was completely enclosed within the endothelial cell cytoplasm, and emerged from the endothelial cell to occupy the subendothelial space. Evidence is presented from static transmission electron microscopic pictures for the migration of lymphocytes by both interendothelial and transendothelial routes through the high endothelial venule. 相似文献
9.
S. Ohsaki S. Teraoka T. Tojimbara K. Takahasi H. Toma T. Agishi K. Ota 《Transplant international》1992,5(Z1):S100-S103
Prostaglandin E1 (PGE1) was used in renal transplant recipients with living related donors. The drug was given intravenously from day 1 to day 7 after transplantation at a dose of 40 µg/kg twice a day. A total of 45 patients were studied divided into two groups: 25 patients were treated with PGE1 (group B) and the remaining 20 patients did not receive the drug (group A). In group B, 24-h creatinine clearance (Ccr) was 66 ± 12.8 ml/min compared with 40.3 ± 13.4 ml/min in group A on the fifth postoperative day (P < 0.05). Urinary levels of N-acetyl-β-d -glucosaminidase (NAG) and serum levels of platelet factor 4 (PF4) in group B were significantly lower than in group A. On the fourth postoperative day, the urinary excretion of thromboxan B2 (TxB2) in group A was higher than in group B, but not significantly (5.1 ± 3.0 ng/day and 2.8 ± 1.1 ng/day, respectively). Acute rejection occurred in four patients in group B and in 10 patients (40%) in group A. The percentage of Leu2a-positive lymphocytes in group B was higher than in group A. We conclude that postoperative administration of PGE1 improves graft function in kidneys from living related donors. 相似文献
10.
目的探讨麻风病患者外周血相关免疫分子的变化和临床意义。方法应用流式细胞分析仪,以荧光标记的鼠抗人单克隆抗体对16例麻风病患者外周血淋巴细胞CD3/CD4/CD8、CD3/CD(16 56)(NK)和CD3/HLA-DR进行测定。结果16例患者发病初期外周血淋巴细胞亚群中CD3^ /CD4^ 、CD3^ /HLA-DR^-检测值和CD4/CD8比值均分别低于健康组相应参数的下限,CD3^ /CD(16 56)^ 和CD3^ /HLA-DR^ 检测值分别高于健康组相应参数的上限、NK的检测值在正常范围内。13例患者治疗病情稳定后2-4周,CD3^ /CD4^ 、CD3^ /HLA-DR^-的检测值和CD4/CD8比值均逐步增高,CD3^ /CD(16 56)^ 、CD3^ /CD8^ 和CD3^ /HLA-DR^ 稍有增高或变化不明显,NK的检测值稍有增高;3例患者病情波动时CD3^ /CD4^ 、CD3^ /HLA-DR^-检测值和CD4/CD8比值较稳定期明显下降,而活化T淋巴细胞CD3^ /CD(16 56)^ 、CD3^ /HLA-DR^ 和NK细胞的检测值较稳定期明显增高2倍以上。结论通过外周血相关免疫分子的动态观察,有助于检测病情变化,时及时治疗和评价疗效有重要意义。 相似文献