全文获取类型
收费全文 | 197892篇 |
免费 | 17140篇 |
国内免费 | 8251篇 |
专业分类
耳鼻咽喉 | 2404篇 |
儿科学 | 4507篇 |
妇产科学 | 2402篇 |
基础医学 | 34213篇 |
口腔科学 | 5533篇 |
临床医学 | 17251篇 |
内科学 | 26769篇 |
皮肤病学 | 4588篇 |
神经病学 | 10671篇 |
特种医学 | 4564篇 |
外国民族医学 | 120篇 |
外科学 | 17413篇 |
综合类 | 31336篇 |
现状与发展 | 48篇 |
预防医学 | 7809篇 |
眼科学 | 3583篇 |
药学 | 15971篇 |
43篇 | |
中国医学 | 6857篇 |
肿瘤学 | 27201篇 |
出版年
2024年 | 256篇 |
2023年 | 2639篇 |
2022年 | 3611篇 |
2021年 | 7054篇 |
2020年 | 6306篇 |
2019年 | 5930篇 |
2018年 | 6151篇 |
2017年 | 6505篇 |
2016年 | 6847篇 |
2015年 | 7704篇 |
2014年 | 11987篇 |
2013年 | 13069篇 |
2012年 | 11406篇 |
2011年 | 12688篇 |
2010年 | 10401篇 |
2009年 | 9987篇 |
2008年 | 10344篇 |
2007年 | 10565篇 |
2006年 | 9642篇 |
2005年 | 8747篇 |
2004年 | 7723篇 |
2003年 | 6712篇 |
2002年 | 5544篇 |
2001年 | 4789篇 |
2000年 | 4055篇 |
1999年 | 3608篇 |
1998年 | 3362篇 |
1997年 | 3095篇 |
1996年 | 2762篇 |
1995年 | 2447篇 |
1994年 | 2176篇 |
1993年 | 1843篇 |
1992年 | 1506篇 |
1991年 | 1412篇 |
1990年 | 1121篇 |
1989年 | 1036篇 |
1988年 | 1010篇 |
1987年 | 821篇 |
1986年 | 733篇 |
1985年 | 954篇 |
1984年 | 896篇 |
1983年 | 606篇 |
1982年 | 662篇 |
1981年 | 545篇 |
1980年 | 471篇 |
1979年 | 358篇 |
1978年 | 282篇 |
1977年 | 226篇 |
1976年 | 166篇 |
1973年 | 116篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Objective:To explore the effect of the Nephritis No.3(N-3)recipe on nitric oxide(NO),nitric oxide synthase(NOS)secreted by cultured mesangial cells(MC)and its gene expression of the in-ducible nitric oxide synthase(iNOS).Methods:The drug(nephritis No.3)-containing serum was preparedwith serum pharmacological technique,and then was applied to react on mesangial cells cultured In fetalcalf serum(FCS)and cells cultured in FCS plus lipopolysaccharide.To observe the secretion of NO andNOS and the gene expression of iNOS by means of RT-PCR.Results:Under the two kinds of culture con-ditions,the content of NO and NOS in the groups with drug-containing serum were higher than thosewithout drug-containing serum(P<0.05,P<0.01),and the expression of iNOS mRNA was up-regula-ted too.Conclusion:The N-3 could significantly promote the secretion of NO and NOS and the mRNA ex-pression of iNOS in rats. 相似文献
992.
Hiromitsu Matsuzaki Hiroyuki Hata Norio Asou Minoru Yoshida Fumihiko Matsuno Motohiro Takeya Kazunari Yamaguchi Isao Sanada Kiyoshi Takatsuki 《Cancer science》1992,83(5):450-457
A stable cell line, KHM-3S, was established from a patient with small cell lung cancer (SCLC), who had a high serum level of soluble interleukin 2 receptors (sIL2-R) and was seropositive for human T cell leukemia virus (HTLV)-l. KHM-3S cells were positive for IL2-R (Tac) and NKH-1, but negative for other lymphocytic markers such as OKT 11, OKT 4, OKT 8, T cell receptor (WT 31), B 1, and B 4. Moreover, the KHM-3S cells were negative for leukocyte common antigen and strongly positive for neuron-specific enolase (NSE). Secretion of sIL2-R and NSE by the KHM-3S line was detected by an enzyme-linked immunosorbent assay. Rearrangement of the T cell receptor gene and monoclonal HTLV-1 integration were found by Southern blot analysis of KHM-3S DNA. However, Northern blot analysis showed no T cell receptor mRNA. KHM-3S may be useful for studies on the role of HTLV-1 in carcinogenesis and IL2-R expression in SCLC. 相似文献
993.
应用SLAB免疫酶标法在石蜡切片上半定量分析增殖细胞核抗原(PCNA)的表达与73例胃癌患者预后的关系,探讨其临床应用价值。结果表明,以PCNA阳性细胞50%为界线,阳性率>50%者术后生存期较短,5年生存率较低,而淋巴结转移率则较高。提示PCNA检测可作为胃癌预后判断的良好指征。 相似文献
994.
本研究用免疫细胞化学方法(ABC法)观察了降钙素基因相关肽(CGRP)在SD大鼠肺中的分布,缺氧对肺中神经内分泌细胞内CGRP含餐的影响。结果表明:含CGRP的神经纤维分布在肺血管平滑肌层中及其周围、气管-支气管树的粘膜下层;含CGRP的神经内分泌细胞位于气管一支气管树的上皮层、粘液腺中和肺实质内。缺氧不引起火鼠肺的神经内分泌细胞数目改变,但可使这些细胞内的CGRP含量增加。 相似文献
995.
Markku Leino MD Kalevi Pyörälä Seppo Lehto Arto Rantala 《Documenta ophthalmologica. Advances in ophthalmology》1992,80(4):309-315
Lens opacity studies were performed using an electronic Lens Opacity Meter (Interzeag Opacity Lensmeter 701) in a population (n = 321) with ischaemic heart disease. These patients are participating in a trial targetting at the reduction of mortality and incidence of myocardial infarction using a cholesterol-lowering drug, simvastatin. A separate study to evaluate the reliability of the method showed good reproducibility. Repeated measurements after a short time-interval (2–10 days) gave statistically lower opacity values either due to a change in lens transparency or perhaps a change in pigment and cell dispersion in the acqueous caused by repeated mydriasis. Lens opacity values showed a highly significant positive correlation to age. Serum cholesterol, systolic blood pressure and smoking habits showed no significant correlations to the levels of lens opacity when adjustments for age were made.Abbreviations HMG-CoA
hydroxy-methylglutarylcoenzyme A
- 4S
Scandinavian Simvastatin Survival Study
- LOM
lens opacity meter 相似文献
996.
桡骨头切除对肘关节稳定性影响的生物力学研究 总被引:25,自引:6,他引:19
目的:探讨桡骨头粉碎性骨折不同治疗方法对肘关节稳定性的影响。方法:将10个尸体标本,分别测定在其它组织无损伤时,肘内侧副韧带切断时,肘内侧副韧带和前臂骨间膜均切断时的力-位移曲线(纵向位移)及肘外翻角。结果:肘内侧副韧带切断时的纵向位移及肘外翻角均大于其它组织无损伤时;肘内侧副韧带和前臂骨间膜均切断时的纵向位移及肘外翻角均大于其它组织无损伤时和肘内侧副韧带切断时,两两间比较均有显著性差异(P<0.001)。结论:在其它组织无损伤时,单纯桡骨头切除是安全的;合并肘内侧副韧带损伤时,可在有效修补韧带的同时作单纯头切除,必要时行假体置换;合并肘内侧副韧带和前臂骨间膜均损伤时,最好作假体置换。 相似文献
997.
指骨内原发性腱鞘巨细胞瘤四例报告 总被引:3,自引:1,他引:2
指骨原发性骨内腱鞘巨细胞瘤较罕见,本院曾收治4例,作一报道。其临床特征是患指指骨增粗,有隐痛感.X线片显示指骨皮质骨膨胀性变而,极似指骨内生软骨瘤。组织学特征是组织细胞性基质细胞增殖,胞浆里网状空泡样改变,并有散在的多核巨细胞存在。诊断时需与骨巨细胞瘤相鉴别.4例均行病灶刮除加酒精灭活植骨治疗,术后随访平均13个月.功能恢复良好.未见复发.指骨内原发性腱鞘巨细胞瘤主要诊断依据必须结合病理改变及X线片表现,才能和其他有关肿瘤相鉴别. 相似文献
998.
本文以体外红系祖细胞培养方法。观察白血病细胞相关抑制物对正常红系祖细胞(CFU-E)的抑制作用。10/10例初发未治急性白血病病人的白血病细胞培养液对CFU-E的生长均有抑制,抑制率25.4~67.4%,平均抑制率为44.35%。结果提示,白血病细胞相关抑制物对正常红细胞系造血也有抑制作用。 相似文献
999.
生长抑素受体亚型在人鼻咽癌细胞株CNE2中表达 总被引:3,自引:0,他引:3
背景与目的:生长抑素受体(somatostatin receptor SSTR)在许多肿瘤组织均有表达,为生长抑素类似物如奥曲肽用于这些肿瘤的治疗提供了生物学基础,但对生长抑素受体在鼻咽癌中表达情况的研究甚少。本研究旨在了解生长抑素受体基因在鼻咽癌细胞中的表达情况,为生长抑素类似物用于鼻咽癌治疗的进一步研究提供试验基础。方法:采用RT—PCR法和SP免疫组化法联合检测体外培养的人鼻咽癌细胞株CNE2的SSTRs表达,并对PCR mRNA产物测序以鉴定结果。结果:RT—PCR提示人鼻咽癌细胞株CNE2分别表达生长抑素受体亚型SSTR1、SSTR2、SSTR4;免疫组化结果:人鼻咽癌细胞株CNE2表达SSTR1、SSTR2A为强阳性(〉60%),表达SSTR4为弱阳性、SSTR2介于两者之间、SSTR3和SSTR5则无表达。结论:我们的研究证实人鼻咽癌细胞株CNE2有多种生长抑素受体亚型基因表达,且以表达SSTR1、SSTR2较多。 相似文献
1000.
B. Ruiter V. Trégoat L. M''Rabet J. Garssen C. A. F. M. Bruijnzeel-Koomen E. F. Knol E. van Hoffen 《Clinical and experimental allergy》2006,36(3):303-310
BACKGROUND: One to two percent of infants suffer from IgE-mediated allergic reactions against cow's milk proteins. Most children develop clinical tolerance, but approximately 15% are still allergic by the age of 10 years. Little is known about the T cell epitopes in individual cow's milk protein in relation to allergy and tolerance. OBJECTIVE: To identify T cell epitopes in alphas1-casein, the most abundant milk protein, and to investigate T cell responses toward these epitopes in allergic, atopic and non-atopic children. METHODS: Allergen-specific T cell lines (TCLs) were derived from peripheral blood mononuclear cells of 11 cow's milk allergic, nine atopic and nine non-atopic children. T cell responses were measured to alphas1-casein and to overlapping peptides (18-mers), spanning the alphas1-casein molecule. Proliferation was determined by incorporation of (3)H-thymidine, and cytokine production (IL-10, IL-13 and IFN-gamma) was measured by ELISA. RESULTS: Four main regions (amino acid (AA) residues 43-66, 73-96, 91-114 and 127-180) in the alphas1-casein molecule were immunogenic to T cells, among which the AA residues 133-156 spanned the immunodominant part. Only subtle differences were found in peptide recognition between the subject groups. Some of the peptides induced slightly Th1- or Th2-skewed cytokine responses. The increased levels of IL-10 in response to alphas1-casein observed in TCLs from atopic children appeared not to be linked to recognition of specific IL-10-inducing epitopes. CONCLUSIONS: The immunodominant sequence in alphas1-casein is spanned by AA residues 133-156. Tolerance towards alphas1-casein in atopic children may be mediated by an overall induction of IL-10 and not by recognition of certain T cell epitopes. The identified T cell epitopes in children with cow's milk allergy may be useful targets in developing peptide immunotherapy. 相似文献