全文获取类型
收费全文 | 614篇 |
免费 | 24篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 41篇 |
妇产科学 | 13篇 |
基础医学 | 47篇 |
口腔科学 | 32篇 |
临床医学 | 41篇 |
内科学 | 192篇 |
皮肤病学 | 14篇 |
神经病学 | 12篇 |
特种医学 | 151篇 |
外科学 | 26篇 |
综合类 | 12篇 |
预防医学 | 17篇 |
眼科学 | 3篇 |
药学 | 24篇 |
中国医学 | 1篇 |
肿瘤学 | 17篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 10篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 8篇 |
2017年 | 5篇 |
2016年 | 2篇 |
2015年 | 9篇 |
2014年 | 17篇 |
2013年 | 14篇 |
2012年 | 7篇 |
2011年 | 16篇 |
2010年 | 32篇 |
2009年 | 36篇 |
2008年 | 23篇 |
2007年 | 13篇 |
2006年 | 11篇 |
2005年 | 11篇 |
2004年 | 12篇 |
2003年 | 12篇 |
2002年 | 3篇 |
2001年 | 9篇 |
2000年 | 11篇 |
1999年 | 14篇 |
1998年 | 26篇 |
1997年 | 37篇 |
1996年 | 45篇 |
1995年 | 29篇 |
1994年 | 24篇 |
1993年 | 35篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1990年 | 15篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1987年 | 18篇 |
1986年 | 21篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 18篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 1篇 |
1977年 | 9篇 |
1976年 | 7篇 |
1975年 | 7篇 |
1971年 | 1篇 |
排序方式: 共有645条查询结果,搜索用时 0 毫秒
31.
Opinion statement
相似文献
– | Pancreatic cystic neoplasms are uncommon, but are being detected at an increased rate in the current era of sophisticated abdominal imaging. The selection of appropriate treatment depends on the ability to distinguish benign from malignant cysts. The most common clinical mistake is to treat a cystic neoplasm as a benign pseudocyst. |
– | The identification of a cyst as a cystic neoplasm should be suspected on clinical grounds, but the differentiation from a benign cyst is often difficult based on clinical features and imaging alone. Analysis of cystic fluid for tumor markers and cytology should be considered, using newer approaches such as endoscopic ultrasound-guided fine needle aspiration (FNA), in those patients in whom this information may guide appropriate therapy. |
– | Surgical excision of a cystic pancreatic neoplasm is the treatment of choice in patients fit for surgery. Inappropriate treatment of these lesions as pseudocysts, by radiographic, endoscopic, or surgical drainage, is to be avoided. Resection of the lesion should be seriously considered even in the absence of symptoms, as these lesions have malignant potential and are often curable. |
32.
V Kannan CE Deopujari BK Misra PG Shetty MM Shroff AM Pendse 《Journal of Medical Imaging and Radiation Oncology》1999,43(3):339-341
Gamma knife was installed at the PD Hinduja National Hospital and Medical Research Centre, Mumbai, India, in January 1997. In the first year of gamma-knife radiosurgery to January 1998, we treated 110 patients, of whom six had medically refractory trigeminal neuralgia. Seven treatments were administered to this group of six patients (one had bilateral neuralgia). This report evaluates the effectiveness of radiosurgery treatment in these patients. The median age of the patients was 56 years and there were five males and one female. Following Leksell stereotactic frame fixation, a magnetic resonance imaging scan was done in all. The Leksell gamma plan was used for planning. A radiosurgery dose of 70–80 Gy was delivered to the trigeminal root entry zone, 2–4 mm anterior to the junction of the pons and trigeminal nerve with a single 4 mm collimator helmet. Complete pain relief was achieved in four patients. Two had partial relief. No patient developed any radiosurgery related morbidity during the follow-up period of 5–16 months. Radiosurgery seems to be an effective approach for medically or surgically refractory trigeminal neuralgia. 相似文献
33.
Three sibs all presented in the early neonatal period with a salt-losing syndrome. The salt-losing form of congenital adrenal hyperplasia was diagnosed and appropriate treatment with glucocorticosteroids, mineralocorticosteroids, and additional dietary salt started. Although early life was maintained with difficulty, with age all 3 children required decreasing amounts of replacement steroids to maintain normal plasma electrolyte balance. They were reinvestigated at the ages of 15 years and 8 years (twins), when cortisol synthesis and metabolism proved normal, but aldosterone synthesis was blocked by deficiency of 18-dehydrogenase. Rational treatment of these cases of a salt-losing syndrome in which aldosterone synthesis alone is blocked due to lack of the enzyme 18-dehydrogenase requires the administration of a mineralocorticosteroid drug only. Since deoxycorticosterone (acetate or pivalate) requires intramuscular administration, as life-long therapy oral fludrocortisone is preferable. Although fludrocortisone has glucocorticoid activity, the "hydrocortisone equivalent" effect of the small dosage used was unlikely to inhibit either pituitary corticotrophin or growth hormone production. 相似文献
34.
35.
目的 研究Ewing’s肉瘤细胞系 (RM 82 )X 射线外照射后肿瘤坏死因子 (TNF α)和转化生长因子 (TGF β)mRNA表达水平的变化 ,探讨X 射线诱导内源性TNF α和TGF β产生的可能性及意义。 方法 应用实时荧光RT PCR ,检测接受不同剂量X 线照射 (2Gy ,5Gy ,10Gy ,2 0Gy ,30Gy ,4 0Gy)和受照后不同时间 (1h ,3h ,6h ,12h ,2 4h ,4 8h ,72h)。TNF α和TGF βmRNA表达水平的变化。 结果 RM 82细胞TNF αmRNA表达水平较外照射前显著升高。一方面受照后TNF αmRNA表达逐渐升高 ,照射剂量达 4 0Gy时TNF αmRNA表达水平达高峰 ,为正常对照组的 10 8倍 ;另一方面 ,照射后 3h后TNF αmRNA表达逐渐升高 ,6h达高峰 ,为正常对照组的 18倍。相反 ,TGF βmRNA表达水平X 射线照射前后无显著变化。结论 Ewing’s肉瘤细胞系 (RM 82 )接受X 线照射后TNF αmRNA表达明显升高 ,且呈现时间、剂量依赖性。放射治疗可诱导Ewing’s肉瘤细胞系 (RM 82... 相似文献
36.
37.
In a previous study we have shown that monoclonal antibody F1 (MoAb F1), directed against an epitope on the heavy chain of factor XII distinct from the binding site for anionic surfaces, is able to activate factor XII in plasma (Nuijens JH, et al: J Biol Chem 264; 12941, 1989). Here, we studied in detail the mechanism underlying the activation of factor XII by MoAb F1 using purified proteins. Formation of factor XIIa was assessed by measuring its amidolytic activity towards the chromogenic substrate H-D-Pro-Phe-Arg-pNA (S-2302) in the presence of soybean trypsin inhibitor and by assessing cleavage on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Upon incubation with MoAb F1 alone, factor XII was auto-activated in a time-dependent fashion, activation being maximal after 30 hours. Factor XII incubated in the absence of MoAb F1 was hardly activated by kallikrein, whereas in the presence of MoAb F1, but not in that of a control MoAb, the rate of factor XII activation by kallikrein was promoted at least 60-fold. Maximal activation of factor XII with kallikrein in the presence of MoAb F1 was reached within 1 hour. This effect of kallikrein on the cleavage of factor XII bound to MoAb F1 was specific because the fibrinolytic enzymes plasmin, urokinase, and tissue-type plasminogen activator could not substitute for kallikrein. Also, trypsin could easily activate factor XII, but in contrast to kallikrein, this activation was independent of MoAb F1. SDS-PAGE analysis showed that the appearance of amidolytic activity correlated well with cleavage of factor XII. MoAb F1-induced activation of factor XII in this purified system was not dependent on the presence of high- molecular-weight kininogen (HK), in contrast to the activation of the contact system in plasma by MoAb F1. Experiments with deletion mutants revealed that the epitopic region for MoAb F1 on factor XII is located on the kringle domain. Thus, this study shows that binding of ligands to the kringle domain, which does not contribute to the proposed binding site for negatively charged surfaces, may induce activation of factor XII. Therefore, these findings point to the existence of multiple mechanisms of activation of factor XII. 相似文献
38.
目的:观察开道散合扶正和胃合剂治疗上消化道癌性狭窄的临床疗效。方法:对40例患者采用口服开道散、扶正和胃合剂联合胃镜下癌灶内注射5-氟脲嘧啶注射液及鸦胆子乳剂方法治疗上消化道癌性狭窄。结果:治疗后无瘤灶消失病例,34例患者肿瘤缩小达50%以上,完全缓解0例,部分缓解34例,稳定4例,进展2例,有效率为85.0%。治疗后患者吞咽困难有了较明显的改善,显效7例,有效31例,无效2例,总有效率95.0%。治疗后所有患者的卡氏评分均有所升高,与治疗前比较,差异有显著性意义(P〈0.05),提示治疗后患者的生活质量有所改善。结论:开道散合扶正和胃合剂治疗上消化道癌性狭窄疗效满意,能使实体瘤缩小、吞咽困难改善、生活质量提高。 相似文献
39.
40.
Human MSH2 binds to trinucleotide repeat DNA structures associated with neurodegenerative diseases 总被引:5,自引:5,他引:5
The expansion of trinucleotide repeat sequences is associated with several
neurodegenerative diseases. The mechanism of this expansion is unknown but
may involve slipped-strand structures where adjacent rather than perfect
complementary sequences of a trinucleotide repeat become paired. Here, we
have studied the interaction of the human mismatch repair protein MSH2 with
slipped-strand structures formed from a triplet repeat sequence in order to
address the possible role of MSH2 in trinucleotide expansion. Genomic
clones of the myotonic dystrophy locus containing disease-relevant lengths
of (CTG)n x (CAG)n triplet repeats were examined. We have constructed two
types of slipped-strand structures by annealing complementary strands of
DNA containing: (i) equal numbers of trinucleotide repeats (homoduplex
slipped structures or S-DNA) or (ii) different numbers of repeats
(heteroduplex slipped intermediates or SI-DNA). SI-DNAs having an excess of
either CTG or CAG repeats were structurally distinct and could be separated
electrophoretically and studied individually. Using a band-shift assay, the
MSH2 was shown to bind to both S-DNA and SI-DNA in a structure- specific
manner. The affinity of MSH2 increased with the length of the repeat
sequence. Furthermore, MSH2 bound preferentially to looped-out CAG repeat
sequences, implicating a strand asymmetry in MSH2 recognition. Our results
are consistent with the idea that MSH2 may participate in trinucleotide
repeat expansion via its role in repair and/or recombination.
相似文献