全文获取类型
收费全文 | 71301篇 |
免费 | 5799篇 |
国内免费 | 3278篇 |
专业分类
耳鼻咽喉 | 196篇 |
儿科学 | 1327篇 |
妇产科学 | 829篇 |
基础医学 | 12694篇 |
口腔科学 | 739篇 |
临床医学 | 5539篇 |
内科学 | 16733篇 |
皮肤病学 | 1073篇 |
神经病学 | 2648篇 |
特种医学 | 1293篇 |
外国民族医学 | 9篇 |
外科学 | 3877篇 |
综合类 | 10539篇 |
现状与发展 | 19篇 |
预防医学 | 6009篇 |
眼科学 | 486篇 |
药学 | 8829篇 |
18篇 | |
中国医学 | 3557篇 |
肿瘤学 | 3964篇 |
出版年
2023年 | 797篇 |
2022年 | 1853篇 |
2021年 | 2290篇 |
2020年 | 2150篇 |
2019年 | 2407篇 |
2018年 | 2273篇 |
2017年 | 2238篇 |
2016年 | 2602篇 |
2015年 | 2863篇 |
2014年 | 4651篇 |
2013年 | 4845篇 |
2012年 | 4777篇 |
2011年 | 5088篇 |
2010年 | 4120篇 |
2009年 | 3920篇 |
2008年 | 3873篇 |
2007年 | 3760篇 |
2006年 | 3427篇 |
2005年 | 2927篇 |
2004年 | 2424篇 |
2003年 | 2102篇 |
2002年 | 1710篇 |
2001年 | 1497篇 |
2000年 | 1155篇 |
1999年 | 1009篇 |
1998年 | 925篇 |
1997年 | 767篇 |
1996年 | 648篇 |
1995年 | 661篇 |
1994年 | 565篇 |
1993年 | 462篇 |
1992年 | 440篇 |
1991年 | 349篇 |
1990年 | 318篇 |
1989年 | 285篇 |
1988年 | 238篇 |
1987年 | 205篇 |
1986年 | 170篇 |
1985年 | 443篇 |
1984年 | 460篇 |
1983年 | 371篇 |
1982年 | 379篇 |
1981年 | 316篇 |
1980年 | 292篇 |
1979年 | 261篇 |
1978年 | 205篇 |
1977年 | 159篇 |
1976年 | 176篇 |
1975年 | 153篇 |
1974年 | 126篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
41.
42.
Alf Grandien Yves Modigliani Antonio Coutinho Jan Andersson 《European journal of immunology》1993,23(7):1561-1565
Using B cells from the transgenic mouse line B6-Sp6 and control littermates, stimulated by lipopolysaccharide (LPS) under novel culture conditions that provide for the response of all B cells, we show here that specific ligation of the surface IgM molecules always results in inhibition of terminal differentiation and immunoglobulin secretion by activated cells, regardless of the ligand. Thus, monoclonal antibodies to (a) the CH region of Ig (anti-μ. and anti-allotype), (b) the Cx region, (c) the V region (anti-idiotype) of surface IgM, as well as (d) multivalent antigen (2,4,6-trinitrophenyl-bovine serum albumin), all show similar effects and dose-response curves. IgD-negative transgenic B cells are equally sensitive to IgM ligation-dependent inhibition, as control (IgD-positive) B cells. The allotype specificity of this inhibition, assessed by using anti-u, allotype reagents to inhibit and assay the responses, suggests that B cells expressing transgenic or endogenous IgM in transgenic B6-Sp6 mice are largely independent populations. These observations establish that anti-IgM antibodies in conjunction with appropriate LPS stimulation, provide a universal model system for functional characterization of B cell responses. 相似文献
43.
柯萨奇病毒诱发实验性多发性肌炎的初步研究 总被引:4,自引:0,他引:4
分别用不同量的柯萨奇病毒B1、2、3感染和兔肌匀浆加完全弗氏佐剂免疫正常豚鼠;拟建立多发性肌炎模型。结果发现:0.1ml毒力为10-5TCID50柯萨奇病毒B1感染豚鼠组,3周后出现多发性肌炎症状。肌酶谱异常与其它组有明显差异,病理检查证实为多发性肌炎改变。单纯兔肌匀浆免疫对照组未发病。提示柯萨奇病毒B1感染及感染的病毒量与多发性肌炎的发病相关 相似文献
44.
本文收集了我省十年(1974—1983)来诊断为恶性淋巴瘤的病例,按免疫功能分类复查了全部切片,最后确诊为非何杰金氏恶性淋巴瘤(NHL)528例,进行了分析。本组NHL在首发部位、类型分布等方面与国内外有所不同。本组NHL首发于淋巴结外的占64.02%,明显高于国内其它省、市,而滤泡型淋巴瘤则低于国内多数地区。T细胞淋巴瘤占14.84%,较国内、外均低。并提出提高制片质量和广泛开展及应用免疫学技术的重要性。 相似文献
45.
The harsh treatment of former prisoners of war (POWs) of World War II and the Korean conflict resulted in severe malnutrition. Although rarely linked to specific long-term medical problems, a specific marker of malnutrition, self-reported lower limb edema (presumably due to a vitamin B deficiency) was associated with a three-fold increase in subsequent death attributed to ischemic heart disease (IHD) during the follow-up period from 1967 through 1975. Although there is at present no medical basis for linking edema, which is perhaps a marker for some unmeasured risk factor, to subsequent IHD, this finding may nonetheless have medical implications for the group of former POWs and other populations with severe dietary deficiency. It also suggests there may be a need to reexamine currently held theories on malnutrition and subsequent chronic disease. 相似文献
46.
Robert S. Mathias 《Pediatric nephrology (Berlin, Germany)》1997,11(3):355-357
. This is a report of unexplained anemia that persisted for 4 months in an adolescent renal transplant patient receiving immunosuppression
that included prednisone, tacrolimus, and mycophenolate mofetil. This patient required monthly blood transfusions for fatigue,
palpitations, and hematocrit levels between 15% and 17%. In addition, his posttransplant course was notable for the development
of insulin-dependent diabetes mellitus. While receiving low-dose prednisone, he was switched from tacrolimus to cyclosporin
and tapered off insulin injections over the next 2 months. At 4.5 months post-transplantation, further diagnostic evaluation
was suggestive of parvovirus B19 infection as the cause for our patient’s chronic anemia. After testing negative for serum-specific
parvovirus B19 IgM and IgG antibodies, parvovirus B19 infection was detected in blood by the polymerase chain reaction. Treatment
with intravenous immunoglobulin (1 g/kg per day × 2 days) resulted in normalization of both his reticulocyte count and hematocrit
within 6 weeks. At 4 months after receiving the immunoglobulin infusion, he has maintained a normal hematocrit level and stable
renal function without requiring further blood transfusions.
Received August 23, 1996; received in revised form and accepted November 20, 1996 相似文献
47.
Leukotriene B4 (LTB4) and the protein kinase C activator, 4-beta-phorbol dibutyrate (PDBu), both induced a pronounced and concentration-dependent stimulation of hydrogen peroxide (H2O2) generation by purified guinea pig peritoneal eosinophils in the concentration range 1 nM-1 microM. The LTB4 response was inhibited competitively by the specific LTB4 receptor antagonist, U-75302, with a KB of 25 nM, while the concentration-response curves for both stimuli were shifted rightwards (3.8-fold and 2.8-fold for LTB4 and PDBu, respectively) by the competitive protein kinase C inhibitor, 1-O-hexadecyl-2-O-methylglycerol at a concentration of 300 microM. LTB4 appears, therefore, to induce respiratory burst in eosinophils via a receptor-mediated mechanism involving protein kinase C. 相似文献
48.
停跳或不停跳心脏手术对血清 S-100B蛋白表达的影响 总被引:2,自引:1,他引:1
【目的】研究心脏手术围术期血清S-100B蛋白表达及其与停跳或不停跳心肺转流方式和时间的关系。【方法】体外循环心脏手术患者23例,测转流前、转流10min、转流末、转流后24h的血清S-100B蛋白表达水平。【结果】①血清S-100B蛋白质量浓度在体外循环前后动态变化:转流前(M)为0.27μg/L,转流10min后升至0.57μg/L(P<0.01),转流末达峰值1.80μg/L(P<0.01),转流后24h降为0.22μg/L(P>0.05)。转流末的血清S-100B蛋白质量浓度与转流时间呈正相关(r=0.488,P<0.05)。②停跳组(n=6)转流前、转流10min、转流末、转流后24h平均血清S-100B蛋白质量浓度分别为(0.17±0.09)μg/L、(0.48±0.13)μg/L、(1.65±0.52)μg/L和(0.19±0.04)μg/L,不停跳组(n=6)分别为(0.26±0.14)μg/L、(0.71±0.41)μg/L、(1.59±0.84)μg/L和(0.23±0.11)μg/L,两组差别无统计学意义(P>0.05)。【结论】体外循环可导致血清S-100B蛋白表达增高,其表达水平与心肺转流时间呈正相关,但与停跳或不停跳转流方式无关。 相似文献
49.
50.
Cross-linking induced interactions between the membrane form of immunoglobulin (mIg) and the cytoskeletal matrix have been described by several groups. To date, the function of mIgM association with the cytoskeleton is not yet understood. Delineation of the molecular basis of these interactions will be instrumental in elucidating their function. We have previously shown that the Igα/β heterodimer is not required for ligand-induced mIgM binding to the cytoskeleton. In this study, we have investigated the role of other B cell-specific proteins in mediating these interactions. For this, we expressed mIgM in the non-hematopoietic human cervical carcinoma cell line HeLa S3 and verified the capacity of the surface-expressed IgM to interact with the cytoskeletal matrix upon cross-linking with anti-μ chain antibodies. We show here that only the mIgM molecule itself and no other B cell-specific protein(s) is required in mediating mIgM interactions with actin filaments. In an attempt to determine the cytoskeleton-binding site of mIgM we investigated the role of the cytoplasmic tail of mIgM (KVK) in binding the receptor to actin-based microfilaments. Using mutated forms of mIgM expressed in J558L cells, we show here that KVK plays a role in mediating these interactions. The absence of KVK did not, however, completely abrogate mIgM-cytoskeletal interactions, suggesting that there are additional molecular requirements for the ligand-induced mIgM binding to the cytoskeletal matrix. 相似文献