全文获取类型
收费全文 | 12927篇 |
免费 | 718篇 |
国内免费 | 405篇 |
专业分类
耳鼻咽喉 | 139篇 |
儿科学 | 235篇 |
妇产科学 | 233篇 |
基础医学 | 2049篇 |
口腔科学 | 192篇 |
临床医学 | 907篇 |
内科学 | 2064篇 |
皮肤病学 | 343篇 |
神经病学 | 786篇 |
特种医学 | 129篇 |
外科学 | 2821篇 |
综合类 | 1607篇 |
预防医学 | 574篇 |
眼科学 | 75篇 |
药学 | 1035篇 |
1篇 | |
中国医学 | 354篇 |
肿瘤学 | 506篇 |
出版年
2024年 | 21篇 |
2023年 | 87篇 |
2022年 | 219篇 |
2021年 | 299篇 |
2020年 | 308篇 |
2019年 | 240篇 |
2018年 | 232篇 |
2017年 | 318篇 |
2016年 | 367篇 |
2015年 | 412篇 |
2014年 | 861篇 |
2013年 | 758篇 |
2012年 | 725篇 |
2011年 | 942篇 |
2010年 | 850篇 |
2009年 | 819篇 |
2008年 | 771篇 |
2007年 | 820篇 |
2006年 | 748篇 |
2005年 | 612篇 |
2004年 | 610篇 |
2003年 | 418篇 |
2002年 | 302篇 |
2001年 | 188篇 |
2000年 | 218篇 |
1999年 | 147篇 |
1998年 | 138篇 |
1997年 | 189篇 |
1996年 | 259篇 |
1995年 | 239篇 |
1994年 | 201篇 |
1993年 | 165篇 |
1992年 | 89篇 |
1991年 | 82篇 |
1990年 | 47篇 |
1989年 | 44篇 |
1988年 | 25篇 |
1987年 | 23篇 |
1986年 | 17篇 |
1985年 | 24篇 |
1984年 | 25篇 |
1983年 | 24篇 |
1982年 | 25篇 |
1981年 | 20篇 |
1980年 | 16篇 |
1979年 | 15篇 |
1977年 | 12篇 |
1976年 | 23篇 |
1975年 | 13篇 |
1974年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
目的研究新生儿肺炎(NP)患儿血清高敏C反应蛋白(hs-CRP)、降钙素原(PCT)、白细胞介素-6(IL-6)水平表达及其意义。方法选取2017年1月-2018年2月韶关市曲江区妇幼保健计划生育服务中心诊治的NP患儿80例,按细菌感染情况分为观察1组和观察2组,各40例。选择同期40例健康新生儿作为对照组。测定并比较三组的hs-CRP、PCT和IL-6水平。结果观察1组血清PCT、hs-CRP和IL-6水平明显高于观察2组和对照组,差异均有统计学意义(P<0.05)。观察1组血清PCT、hs-CRP和1L-6检测阳性率明显高于观察2组和对照组,差异均有统计学意义(P<0.05),且观察1组血清PCT、hs-CRP和1L-6诊断NP的敏感度均明显高于观察2组,差异均有统计学意义(P<0.05);观察组各指标特异度与观察2组比较差异无统计学意义(P>0.05)。结论血清hs-CRP、PCT、IL-6水平可作为NP患儿的辅助鉴别指标,为抗生素的合理使用和疗效提供依据。 相似文献
2.
3.
4.
Johannes Brettschneider Axel Petzold Sigurd D Süssmuth Georg B Landwehrmeyer Albert C Ludolph Jan Kassubek Hayrettin Tumani 《Movement disorders》2006,21(12):2224-2227
We aimed to evaluate the potential of the cerebrospinal fluid (CSF) axonal damage biomarker NfH(SMI35) in the laboratory-supported differential diagnosis of parkinsonian syndromes. Patients with idiopathic Parkinson's disease (PD; n = 22), multiple-system atrophy (MSA; n = 21), progressive supranuclear palsy (PSP; n = 21), corticobasal degeneration (CBD; n = 6), and age-matched controls (n = 45) were included. CSF levels of NfH(SMI35) were measured using ELISA. Levels of CSF NfH(SMI35) were elevated in PSP compared to PD and controls (P < 0.05 each). They were also significantly higher in MSA than in PD and controls (P < 0.05 each). NfH(SMI35) differentiated PD from PSP with a sensitivity of 76.5% and a specificity of 94.4%. Axonal damage as measured by CSF NfH(SMI35) is most prominent in the more rapidly progressive syndromes PSP and MSA as compared to PD or CBD. CSF NfH(SMI35) may therefore be of some value for the laboratory-supported differential diagnosis of atypical parkinsonian syndromes. 相似文献
5.
目的分析体外培养的骨髓单个核细胞持续分泌促血管生长因子的能力。方法从大鼠胫骨及股骨采集骨髓,密度梯度离心法分离出骨髓单个核细胞进行体外培养,并连续收集4周培养上清液。酶联免疫吸附实验(ELISA)法测定培养上清液中碱性成纤维细胞生长因子(bFGF)、血管内皮细胞生长因子(VEGF)和白介素-1β(IL-1β)等因子水平。结果第1、2、3、4周骨髓单个核细胞体外培养上清液中VEGF分别为(24.40±7.99)pg/m、l(89.28±5.13)pg/m、l(115.24±10.08)pg/m、l(157.00±15.64)pg/m l;bFGF含量分别为(52.72±2.13)pg/m、l(48.10±6.41)pg/m、l(44.71±3.21)pg/m、l(25.61±2.42)pg/m l;IL-1β含量分别为:(31.28±5.44)pg/m、l(71.87±3.01)pg/m、l(55.77±11.94)pg/m、l(41.75±9.14)pg/m。l结论体外培养骨髓单个核细胞可持续分泌VEGF、bFGF、IL-1β等多种促血管生长因子。 相似文献
6.
7.
目的 探讨白细胞介素 10 (IL 10 )在过敏性紫癜血管内皮损伤中的作用及机制。方法 建立人脐静脉内皮细胞 (HUVEC)培养模型 ,ELISA法检测过敏性紫癜患儿外周血单个核细胞 (PB MC)活化后培养上清IL 6、IL 1β、TNF α、IL 10等细胞因子的含量 ;AnnexinV/PI双染色法 ,流式细胞仪检测过敏性紫癜患儿PBMC培养上清所诱导的内皮细胞凋亡率。结果 ①过敏性紫癜组PBMC体外刺激活化后IL 6、IL 1β、TNF α、IL 10等细胞因子的分泌量均明显高于对照组 (P <0 0 1) ,其培养上清诱导的内皮细胞凋亡率 (34 7± 10 3) %明显高于对照组 (3 6± 0 9) %。②抗IL 6、IL 1β、TNF α单克隆抗体联合阻断可明显降低过敏性紫癜患儿PBMC培养上清诱导的内皮细胞凋亡率 (2 2 6±5 9) % ,而抗IL 10单克隆抗体阻断则明显增加过敏性紫癜患儿PBMC培养上清诱导的内皮细胞凋亡率 (5 6 9± 16 5 ) %。③于过敏性紫癜患儿PBMC培养上清加入外源性IL 10 ,可明显降低IL 6、IL 1β、INF α等炎性细胞因子的表达 ,并明显降低内皮细胞凋亡率 (11 8± 3 1) %。结论 IL 10作为机体炎症反应负反馈调节过程中的一个重要枢纽 ,在过敏性紫癜炎症因子所介导的血管内皮损伤中起重要的保护作用。 相似文献
8.
Unfractionated cytokines have been shown to induce in vitro proliferation of neonatal rat Schwann cells but the nature of the mitogen(s) is not known. A mixture of rabbit antibodies specific for recombinant interleukin-1α (IL-1α) and interleukin-1β (IL-1β) inhibited Schwann cell proliferation induced by unfractionated human cytokines whereas antibodies to interleukin-2 (IL-2) and control IgG did not. However, purified human IL-1 and recombinant human IL-1α or β did not induce Schwann cell proliferation on their own. 相似文献
9.
Effects of antimicrobial agents on spontaneous and endotoxin-induced cytokine release of human peripheral blood mononuclear cells 总被引:2,自引:0,他引:2
U. Krehmeier M. Bardenheuer G. Voggenreiter U. Obertacke F. U. Schade M. Majetschak 《Journal of infection and chemotherapy》2002,8(2):194-197
Because the immunomodulatory effects of antibiotics could possibly influence the degree of the systemic and local response
to infection, knowledge of their intrinsic influence on the host's inflammatory response appears to be essential. Therefore,
this study investigated the effects of frequently used antimicrobial agents (β-lactams, quinolones gentamicin, vancomycin
and metronidazole) on the in-vitro tumor necrosis factor (TNF)-α and interleukin (IL)-6 production of isolated human peripheral
blood mononuclear cells (PBMNC), cultured with or without endotoxin, in comparison with those effects obtained in a whole-blood
assay system. In the presence of ciprofloxacin, ofloxacin, gentamicin, vancomycin, and metronidazole, a significant inhibition
of the endotoxin-stimulated TNF-α production of human peripheral blood mononuclear cells (PBMNC) was found at therapeutic
levels. Only ofloxacin showed a significant inhibitory influence on the endotoxin-induced IL-6 production of PBMNC. In the
whole-blood assay, significant effects were not detectable. None of the antibiotics showed cytotoxicity. It is concluded that,
at present, the direct immunological effects of antibiotics should be interpreted carefully with regard to the experimental
conditions, and regardless of the therapeutic implications. To assess the potential direct immunomodulatory effect of antimicrobial
agents, different cell culture procedures should be used.
Received: October 19, 2001 / Accepted: February 15, 2002 相似文献
10.
The objective of this study is to determine whether a normal fetal morphology ultrasound scan in women older than 35 years reduces the risk of aneuploidy. We reviewed the results of amniocentesis and second trimester sonogram in all women older than 35 years from 1991 to 1995. None had prior screening. We excluded fetuses with structural anomalies. We determined the sensitivity and specificity of minor markers in detecting Down syndrome and also determined the reduction in risk of a normal sonogram. Among the 2060 women older than 35 years giving birth during the study period, 16 (0.78%) delivered an infant with Down syndrome. Of the 16 fetuses, two had no prenatal testing or ultrasound, two had invasive testing but no second trimester sonogram, five had a normal sonogram and seven had one or more sonographic markers of Down syndrome. At least 17% of women older than 35 years did not participate in prenatal testing or ultrasound. Ultrasound detected Down syndrome with a sensitivity of 59% (95% confidence interval: 45–72%), a false‐positive rate of 10.6% (9.4–11.8%) and a positive predictor value of 1 in 9. The likelihood of having normal karyotype if the sonogram was normal was 0.46 (0.31–0.61). In women older than 35 years, a normal second trimester sonogram reduces the risk of Down syndrome by more than 50%. At least 17% of women older than 35 years do not participate in prenatal testing or ultrasound. 相似文献