全文获取类型
收费全文 | 5645篇 |
免费 | 437篇 |
国内免费 | 187篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 160篇 |
妇产科学 | 58篇 |
基础医学 | 1170篇 |
口腔科学 | 36篇 |
临床医学 | 510篇 |
内科学 | 771篇 |
皮肤病学 | 128篇 |
神经病学 | 217篇 |
特种医学 | 109篇 |
外国民族医学 | 1篇 |
外科学 | 285篇 |
综合类 | 1238篇 |
预防医学 | 358篇 |
眼科学 | 14篇 |
药学 | 513篇 |
3篇 | |
中国医学 | 300篇 |
肿瘤学 | 363篇 |
出版年
2023年 | 36篇 |
2022年 | 83篇 |
2021年 | 160篇 |
2020年 | 184篇 |
2019年 | 111篇 |
2018年 | 93篇 |
2017年 | 155篇 |
2016年 | 158篇 |
2015年 | 160篇 |
2014年 | 241篇 |
2013年 | 274篇 |
2012年 | 268篇 |
2011年 | 310篇 |
2010年 | 242篇 |
2009年 | 223篇 |
2008年 | 215篇 |
2007年 | 244篇 |
2006年 | 273篇 |
2005年 | 239篇 |
2004年 | 225篇 |
2003年 | 252篇 |
2002年 | 168篇 |
2001年 | 175篇 |
2000年 | 180篇 |
1999年 | 139篇 |
1998年 | 144篇 |
1997年 | 143篇 |
1996年 | 106篇 |
1995年 | 137篇 |
1994年 | 149篇 |
1993年 | 101篇 |
1992年 | 98篇 |
1991年 | 97篇 |
1990年 | 81篇 |
1989年 | 63篇 |
1988年 | 43篇 |
1987年 | 46篇 |
1986年 | 32篇 |
1985年 | 54篇 |
1984年 | 52篇 |
1983年 | 26篇 |
1982年 | 30篇 |
1981年 | 13篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1978年 | 3篇 |
1977年 | 11篇 |
1975年 | 3篇 |
1971年 | 2篇 |
1906年 | 1篇 |
排序方式: 共有6269条查询结果,搜索用时 39 毫秒
71.
72.
乙型肝炎表面抗原对BALB/c小鼠细胞免疫应答的影响 总被引:6,自引:3,他引:6
目的研究不同来源乙肝表面抗原(HBsAg)对BALB/c小鼠的某些细胞免疫应答的影响.方法采用血源、CHO和酵母HBsAg分别免疫BALB/c小鼠,于免疫后不同时间制备脾脏单个核细胞(MNC),测定MNC对刀豆蛋白(ConA)和细菌脂多糖(LPS)的增殖反应性;采用绵羊红细胞(SRBC)作为致敏原,测定不同HBsAg免疫小鼠后迟发性超敏反应(DTH)的发生程度.结果不同来源HBsAg对ConA或LPS刺激的反应指数(SI)表现出不同的时间曲线,一般于免疫20?d和25?d时显著升高,其中血源HBsAg较高,酵母较低.H.M.-HBsAg在免疫5?d时即显出较高的SI值.CHO-HBsAg对SRBC诱导的DTH反应具有显著的抑制作用(P<0.05).结论不同来源HBsAg诱导细胞免疫反应的类型和程度存在差异,CHO细胞来源的HBsAg对TH1细胞介导的DTH反应有抑制作用. 相似文献
73.
白术多糖对小鼠淋巴细胞功能的调节 总被引:54,自引:1,他引:54
研究了白术多糖PAM体内及体外对小鼠脾淋巴细胞的调节作用。结果表明:白术多糖PAM在一定的浓度范围内能单独激活或协同ConA/PHA促进正常小鼠淋巴细胞转化并能明显提高IL-2分泌的水平。PAM对氢化可的松造成的免疫抑制小鼠淋巴细胞的增殖功能有恢复作用。同时还发现白术多糖PAM对淋巴细胞的调节与β-肾上腺素受体激动剂异丙肾上腺素相关。 相似文献
74.
75.
76.
R. Paschke I. Harsch B. Schlote I. Vardarli L. Schaaf S. Kaumeier J. Teuber K. H. Usadel 《Journal of molecular medicine (Berlin, Germany)》1990,68(19):942-950
Summary Although the psychological disturbances accompanying Graves' disease are well known, the time required for normalisation of these disturbances during antithyroid drug treatment is not known. Therefore sequential psychological testing during the course of Graves' disease was done. There are also contradictory results concerning the possible correlation of neurophysiological and psychological test results during the course of Graves' disease with thyroid hormone values. Finally, psychological disturbances have been proposed as possible etiologic factors in Graves' disease.In our study, a significant decrease in anxiety and irritability could be observed at the time euthyroidism was achieved. Self-evaluations of depressivity, activity, exhaustion, well-being, extraversion, introversion, and the ability to concentrate changed 1 or 2 months after euthyroidism was induced. Similar test results could be observed after induction of euthyroidism by antithyroid drugs and subtotal thyroid resection. Therefore the mode of therapy does not seem to influence the course of normalisation of psychological parameters.In contrast to other investigations there was hardly any correlation between thyroid hormone values and psychological test results or the ability to concentrate. Nontheless, patients with Graves' disease showing high scores for depression and anxiety exhibit abnormal peripheral helper/suppressor T-lymphocyte relations. Furthermore, patients suffering from Graves' disease tend to be more anxious than controls. It remains to be determined whether an increased susceptibility to psychological disturbances has led to these alterations of lymphocyte subsets in Graves' disease patients with severe depression and anxiety.Supported by SFB 258 相似文献
77.
78.
目的:研究严重急性呼吸综合症(SAPS)患者T细胞亚群变化。方法:检索2003年2月-2004年1月有关SAPS患者T细胞亚群计数研究的论文,汇合成大样本资料,借助先进的RevMan4.2分析软件对这些资料进行二次分析以探讨该病患者T细胞亚群变化。结果:SAPS病程〈14天期间,患者与正常对照比较,CD3^+细胞、CD4^+细胞、CD8^+细胞均显著降低(均P〈0.01)。其中,重症病人(包括重型和极重型)比非重症病人(包括轻型和普通型)降低更显著(均P〈0.01)。病程〉14天恢复期病人与病程〈14天病人比较,CD3^+细胞虽然有了上升,但无显著差异(Z=1.56,P=0.12)。CD4^+细胞、CD8^+细胞均恢复性上升,差异显著(均P〈0.01)。病程〉14天恢复期病人与正常对照比较,CD3^+细胞、CD4^+细胞仍然显著降低(均P〈0.01)。两者的CD8^+细胞有差异(Z=2.28,P=0.02)。结论:①SAPS患者整个病程中都存在CD3^+细胞、CD4^+细胞、CD8^+细胞数量暂时性、严重性、可逆性降低;②患者T细胞亚群数量的下降以重症病人为甚;③这种降低是可逆性的,随着病程进入恢复期,患者T细胞亚群开始恢复性上升。 相似文献
79.
CD4+/CD8+ ratio of liver-derived lymphocytes is related to viraemia and not to hepatitis C virus genotypes in chronic hepatitis C. 下载免费PDF全文
B N Pham M Martinot-Peignoux J F Mosnier C Njapoum P Marcellin F Bougy C Degott S Erlinger J H Cohen F Degos 《Clinical and experimental immunology》1995,102(2):320-327
The pathogenic mechanisms that lead to chronic hepatitis C are unknown. As hepatitis C virus (HCV) has been shown to induce T cell response, we assessed whether a particular T lymphocyte subset could be preferentially detected in the liver of patients with chronic hepatitis C in relation to viraemia or HCV genotypes. The immunophenotypes of liver-derived lymphocytes were analysed in 26 patients by flow cytometry and immunohistochemistry. Viraemia was quantified by branched DNA assay. Using this assay, HCV RNA was not detectable in six patients. HCV RNA was detected in 20 patients, and titres ranged from 8 to 137 x 10(6) Eq/ml. Genotyping was performed using a line probe assay. Type 1a, 1b, 2a, 3a and 4a were found to infect 2, 10, 2, 7 and 3 patients, respectively. The CD4+/CD8+ ratio of liver-derived lymphocytes was significantly higher (P < 0.01) in patients with detectable viraemia than in patients without detectable viraemia. In contrast, neither the percentage of gamma/delta T lymphocytes nor that of CD2+CD57+ cells was different in the groups. When comparing the CD4+/CD8+ ratio, the percentage of gamma/delta T lymphocytes or CD2+CD57+ cells according to genotype, the differences were not significant. These results suggest that the CD4+/CD8+ ratio of liver-derived lymphocytes is related to viraemia but not to HCV genotypes in patients with chronic hepatitis C, and that T lymphocytes may be involved in the pathogenesis of liver lesions in chronic hepatitis C. 相似文献
80.
Mikio Watanabe Dr. Yoshinori Iwatani Tatsunari Kaneda Yoh Hidaka Nobuaki Mitsuda Yasuhiko Morimoto Nobuyuki Amino 《American journal of reproductive immunology (New York, N.Y. : 1989)》1997,37(5):368-377
PROBLEM: Pregnancy affects the maternal immune system and the clinical course of maternal diseases. Here we report the changes in the detailed lymphocyte subsets of helper T cells, suppressor T cells, CD5+ B cells, T cell receptor (TCR) αβ-positive T cells (Tαβ cells), TCRαβ-negative T cell (Tγδ cells), and others during and after pregnancy through to one year postpartum, and discuss the significance of the changes. METHOD: The absolute numbers of helper T cells, suppressor T cells, cytotoxic T cells, TCRαβ-negative T cells (Tγδ cells), CD5— B cells, CD5+ B cells, and NK cell subsets were examined by two-color flow cytometry in peripheral blood from 51 healthy non-pregnant women, 106 healthy pregnant women, and 148 healthy postpartum women. RESULTS: In early pregnancy, the numbers of suppressor T cells and NK cells with strong cytotoxicity (NK+++ cells) increased, and the number of cytotoxic T cells decreased. In late pregnancy, the helper T cell and NK+++ cell numbers decreased. Tαβ, CD5— B and CD5+ B cells decreased during pregnancy. After delivery, helper T cells and cytotoxic T cells increased from 1 to 4 months postpartum, and suppressor T cells increased at 7 months postpartum. TCRαβ-negative T cells increased at 4 to 10 months postpartum. Both CD5— and CD5+ B cells decreased further at 1 month postpartum, but CD5+ B cells increased markedly at 7 to 10 months postpartum. CONCLUSIONS: These data indicate that 1) early increases of suppressor T cells and NK+++ cells during pregnancy may be related to the mechanism to accept or reject the fetus in early pregnancy, respectively; 2) late decreases of helper T cells and NK+++ cells may be related to the maintenance of pregnancy: 3) postpartum increases of helper T cells, cytotoxic T cells, TCRαβ-negative T cells (Tγδ cells), and CD5+ B cells may be related to the postpartum aggravation of autoimmune diseases; and 4) the immunological effects of pregnancy remains until about 1 year after delivery. 相似文献