全文获取类型
收费全文 | 484篇 |
免费 | 12篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 7篇 |
妇产科学 | 4篇 |
基础医学 | 30篇 |
口腔科学 | 33篇 |
临床医学 | 40篇 |
内科学 | 102篇 |
皮肤病学 | 31篇 |
神经病学 | 9篇 |
特种医学 | 91篇 |
外科学 | 47篇 |
综合类 | 22篇 |
预防医学 | 27篇 |
眼科学 | 9篇 |
药学 | 15篇 |
中国医学 | 5篇 |
肿瘤学 | 27篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 9篇 |
2014年 | 11篇 |
2013年 | 20篇 |
2012年 | 30篇 |
2011年 | 40篇 |
2010年 | 24篇 |
2009年 | 23篇 |
2008年 | 19篇 |
2007年 | 17篇 |
2006年 | 13篇 |
2005年 | 6篇 |
2004年 | 11篇 |
2003年 | 7篇 |
2002年 | 9篇 |
2001年 | 9篇 |
2000年 | 11篇 |
1999年 | 10篇 |
1998年 | 14篇 |
1997年 | 15篇 |
1996年 | 18篇 |
1995年 | 14篇 |
1994年 | 8篇 |
1993年 | 12篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 11篇 |
1988年 | 11篇 |
1987年 | 8篇 |
1986年 | 9篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1978年 | 4篇 |
1977年 | 7篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有500条查询结果,搜索用时 15 毫秒
11.
12.
13.
Matthijs F Ravensberg Ewout B Fanoy Jane Whelan Carmen WE Embregts Corine H GeurtsvanKessel Jared B Strydom 《Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin》2022,27(16)
More than 430 cases of rabies have been confirmed in dogs in the Nelson Mandela Bay Metropolitan Municipality of South Africa since July 2021. We describe the ongoing outbreak, its geographical spread and six related human deaths that have occurred. Further investigation of the outbreak and vaccination of the dog population is required. Raising awareness among healthcare providers, the public, and among international travellers planning to visit the region, is key for action to protect human and animal health. 相似文献
14.
H. WULF J. LÖWE K‐H. GNUTZMANN T. STEINFELDT 《Acta anaesthesiologica Scandinavica》2010,54(4):414-420
Background/Objective: Our aim was to evaluate analgesia, motor block and pharmacokinetics of ropivacaine 0.2% and 0.75% in a femoral nerve block (FNB) in day case patients for anterior crucial ligament (ACL)‐reconstruction compared with bupivacaine 0.25% and placebo. Methods: Following ethics committee approval and informed consent, 280 patients were randomly allocated to four groups for single‐shot FNB [30 ml ropivacaine 0.2% (group RO2.0), 0.75% (RO7.5), bupivacaine 0.25% (BU2.5) and NaCl 0.9% (NaCl)]. Analgesia (pain scores, primary outcome) and motor block were assessed at 4 h (dismissal) and up to 24 h. Plasma concentration was determined up to 240 min thereafter. Results: Pain scores at 4 h were significantly higher for NaCl 4 (0–8) (median, range) (vs.) BU2.5 2 (0–8), RO2.0 3 (0–9) and RO7.5 2 (0–8) (NS within the LA groups). Patients of the NaCl group needed analgesics significantly more often (93%) within 4 h after surgery vs. 16% of group RO2.0, 19% of group RO7.5 and 19% of group BU2.5. Motor block was significantly increased with all local anesthetics without a significant difference within the LA groups 3 (0–5) in RO2.0, 3 (0–5) in RO7.5 and 3 (0–4) in BU2.5 vs. 0 (0–3) in group NaCl (median (range); scale from 0=full strength to 5=complete paralysis). Peak plasma concentrations differed significantly: RO7.5: 1.4 ± 0.4 (0.73–2.6) [μg/ml, mean ± SD (range)] after 33 ± 14 (10–40) min, RO2.0: 0.6 ± 0.3 (0.13–1.0) after 22+17 (10–60) and BU2.5: 0.3 ± 0.16 (0.05–0.62) at 31 ± 17 (10–60), respectively. Conclusion: FNB for ACL reconstruction with ropivacaine or bupivacaine provided better post‐operative analgesia than placebo without reaching toxic plasma concentrations. Significant motor block was observed after 4 h in all groups including the lowest concentration of ropivacaine but occurred even with placebo. 相似文献
15.
幽门螺杆菌对人胃癌MKN45细胞p38MAPK信号转导通路激活作用的研究 总被引:2,自引:1,他引:2
背景与目的: 环氧合酶2(cyelooxygenase-2,COX-2)是花生四烯酸转化为前列腺素(prostaglandins,PGs)代谢中重要的限速酶,幽门螺杆菌(Helicobacterpylori,Hp)感染诱导胃黏膜COX-2的过度表达是胃癌发生的重要环节,但Hp感染胃黏膜细胞COX-2表达的机制尚不清楚.本研究旨在揭示Hp对人胃癌MKN45细胞COX-2表达和p38MAPK信号通路的影响,探讨COX-2表达的可能机制.方法: 采用实时荧光定量PCR(real time-PCR)检测Hp标准株NCTC11637感染对人胃痛MKN45细胞COX-2 mRNA转录的影响,Western blot检测坳COX-2蛋白表达的影响和p38MAPK信号通路的激活及其下游因子ATF-2的表达.结果: Hp感染人胃癌MKN45细胞后,COX-2 mRNA的表达明显上调,Hp感染3、6、9、12 h后COX-2 mRNA的表达量分别为正常值的3倍、7.2倍、5.1倍和4.3倍,各时间组COX-2 mRNA表达均明显高于对照组(P<0.01);Up与MKN45细胞共培养24 h后,COX-2蛋白的表达亦显著增加(P<0.01).Hp感染MKN45 20 min后,p38MAPK信号通路被激活,60 min达峰值;p38MAPK下游因子ATF-2的表达也明显增加,2 h达高峰,随着作用时间的延长,表达逐渐下降,24 h仍有表达.结论: Hp感染能诱导人胃癌MKN45细胞COX-2的表达;激活p38MAPK信号通路,增加其下游因子ATF-2的表达,可能是其诱导COX-2表达的机制. 相似文献
16.
目的探讨称重法和化学分析法评估人群矿物质摄入量的差异和相关性。方法同时使用称重法和化学分析法对89名上海市居民进行膳食调查,并对两种调查方法测得的钙、镁、铁、锌、铜、锰摄入量进行比较分析。结果称重法调查的6种矿物质元素的摄入量高于化学分析法(P<0.05),称重法调查的平均每天钙、镁、铁、锌、铜、锰摄入量比化学分析法分别高20.9%、67.4%、19.5%、84.4%、46.7%和33.3%;称重法与化学分析法测得的钙、镁、铁、锌、铜、锰摄入量均呈显著正相关(P<0.01),相关系数分别为0.571、0.672、0.521、0.524、0.538和0.691。结论称重法测得的人群膳食矿物质摄入量高于化学分析法。 相似文献
17.
Human myeloid alpha 3-fucosyltransferase is involved in the expression of the sialyl-Lewis(x) determinant, a ligand for E- and P-selectin 总被引:1,自引:0,他引:1
Easton EW; Schiphorst WE; van Drunen E; van der Schoot CE; van den Eijnden DH 《Blood》1993,81(11):2978-2986
The sialyl-Lex determinant (NeuAc alpha 2-->3Gal beta 1-->4[Fuc alpha- 1-->3]GlcNAc) has been identified as a major ligand in the selectin- mediated adhesion of neutrophils and monocytes to activated endothelium or platelets. This carbohydrate epitope is formed by the sequential action of alpha 3-sialyltransferase and alpha 3-fucosyltransferase on N- acetyllactosamine (Gal beta 1-->4GlcNAc) disaccharide termini of glycoconjugates. We have addressed the role of the human myeloid alpha 3-fucosyltransferase in the expression of this epitope at the leucocyte surface by determining its activity in human-mouse leukemic cell hybrids (WEGLI), normal human granulocytes and chronic myeloid leukemia (CML) cells using sialylated and desialylated glycoproteins and oligosaccharides as acceptor substrates. In contrast to what has been reported for the myeloid-type enzyme, we found that the alpha 3- fucosyltransferase of the cells studied can use sialylated acceptors be it that the activity is several times lower than with asialo- substrates. Characterization of the product obtained with a sialylated oligosaccharide indicated that the enzyme can catalyze the formation of the sialyl-Le(x) structure. Flow cytometry of the WEGLI cells using a sialyl-Le(x)-specific monoclonal antibody (MoAb) showed that these cells indeed express sialyl-Lex at their surface, provided that they contain human chromosome 11. Earlier the presence of this chromosome had been correlated with the expression of alpha 3-fucosyltransferase activity. In addition to sialyl-Le(x), WEGLI cells containing chromosome 11 showed high-expression levels of related structures recognized by antibodies VIM-2 and VIM-8, suggesting that fucose addition can occur at both distal and proximal GlcNAc residues in poly- N-acetyl-lactosaminoglycan sequences. Based on the human chromosome contents it could be ruled out that the alpha 3-fucosyltransferase of WEGLI cells is a Lewis-type alpha 3/4- or plasma-type alpha 3- fucosyltransferase, the genes of which have been mapped to chromosome 19. It is concluded that the enzyme studied is of the myeloid-type and indeed is involved in the synthesis of sialyl-Le(x) (and also VIM-2 and VIM-8 structures) in leukocytes provided that its expression is at a sufficiently high level. 相似文献
18.
Reduction of sound levels with antinoise in MR imaging 总被引:1,自引:0,他引:1
A combination of active and passive techniques was used to reduce the sound levels in magnetic resonance imagers. These techniques were integrated into an existing audio system. Measurements of sound reduction varied with the protocol being used and averaged 9.9 dB with coaxial cabling and 14.2 dB with fiberoptic conduction of the feedback signal to a controller. Patient comfort and communication were improved. 相似文献
19.
Arnstein NB; Shapiro B; Ekhauser FE; Dmuchowski CF; Knol JA; Strodel WE; Nakajo M; Swanson DP 《Radiology》1985,156(2):501-504
Mechanisms by which gastroplasty for morbid obesity causes weight loss are poorly understood. We studied the role of altered gastric emptying in 50 patients before surgery, 1-4 weeks after surgery, and 2-24 months after surgery using technetium-99m pentetate in water for liquid meals and a Tc-99m styrene divinylbenzene copolymer resin in oatmeal for semisolid meals. We determined the emptying half-times of the stomach before and after surgery in the proximal and distal compartments. The proximal compartment emptied promptly in the early and late postoperative periods. The distal compartment emptied liquids at rates similar to those before surgery, while the late postoperative emptying of semisolids was significantly faster. The stoma connecting the two compartments thus permits rapid transit of liquids and semisolids without delay of distal compartment emptying. No correlation was seen between the emptying half-times or changes thereof and eventual weight loss. Delayed gastric emptying is therefore not the mechanism for satiety and weight loss after gastroplasty has been performed. 相似文献
20.
Antunes EN Ferreira EO Falcão LS Paula GR Avelar KE Barroso DE Leite JP Ferreira MC Domingues RM 《Research in microbiology》2004,155(7):522-524
Diarrhoeic stool samples from 334 0-5-year-old children were analysed with respect to the incidence of Bacteroides fragilis as well as other enteropathogens. B. fragilis was recovered in 9.3% (31/334) of the samples, and 79 strains were examined for the presence of the bft gene or the BfPAI flanking region using polymerase chain reaction assays. No enterotoxigenic B. fragilis strains were detected. In 29% (9/31) of the samples the coexistence of both II and III non-toxigenic B. fragilis (NTBF) patterns could be seen. In 51.6% (16/31) of the samples there existed a pattern II NTBF only, and in 19.4% (6/31) only pattern III could be detected. Strains from the same patient representing different patterns were submitted to pulsed-field gel electrophoresis assays. Fingerprints obtained by this technique showed that there was strong heterogeneity among strains from different individuals. However, different patterns from the same individual shared 100% similarity. 相似文献