全文获取类型
收费全文 | 1654篇 |
免费 | 216篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 23篇 |
儿科学 | 125篇 |
妇产科学 | 24篇 |
基础医学 | 190篇 |
口腔科学 | 72篇 |
临床医学 | 220篇 |
内科学 | 368篇 |
皮肤病学 | 18篇 |
神经病学 | 73篇 |
特种医学 | 194篇 |
外科学 | 236篇 |
综合类 | 48篇 |
预防医学 | 133篇 |
眼科学 | 8篇 |
药学 | 53篇 |
中国医学 | 5篇 |
肿瘤学 | 91篇 |
出版年
2021年 | 18篇 |
2020年 | 11篇 |
2019年 | 9篇 |
2018年 | 46篇 |
2017年 | 52篇 |
2016年 | 47篇 |
2015年 | 53篇 |
2014年 | 52篇 |
2013年 | 74篇 |
2012年 | 61篇 |
2011年 | 54篇 |
2010年 | 82篇 |
2009年 | 74篇 |
2008年 | 66篇 |
2007年 | 57篇 |
2006年 | 45篇 |
2005年 | 43篇 |
2004年 | 42篇 |
2003年 | 45篇 |
2002年 | 50篇 |
2001年 | 48篇 |
2000年 | 33篇 |
1999年 | 42篇 |
1998年 | 75篇 |
1997年 | 62篇 |
1996年 | 60篇 |
1995年 | 57篇 |
1994年 | 33篇 |
1993年 | 46篇 |
1992年 | 34篇 |
1991年 | 30篇 |
1990年 | 33篇 |
1989年 | 35篇 |
1988年 | 50篇 |
1987年 | 42篇 |
1986年 | 30篇 |
1985年 | 18篇 |
1984年 | 25篇 |
1983年 | 28篇 |
1982年 | 8篇 |
1981年 | 20篇 |
1980年 | 16篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 12篇 |
1976年 | 13篇 |
1975年 | 8篇 |
1974年 | 4篇 |
1971年 | 4篇 |
1962年 | 3篇 |
排序方式: 共有1881条查询结果,搜索用时 296 毫秒
1.
Gamma-glutamyl transpeptidase (GGT) activity has been demonstratedhistochemically in a number of experimentally induced neoplasmsand has been suggested as a label for potential precursors forthe development of squamous cell carcinomas. This study exploresthe kinetics of GGT-stained cell populations, their correlationwith the hypothesized initiated cells and evidence of malignanttransformation of epithelium in hamster buccal pouch by a 15-weekregime of tri-weekly topical application of 7,12-dimethylbenz[a]anthracene(DMBA) in mineral oil. GGT-positive foci were detected histochemicallyin tissue sections as early as 1 week after application of thecarcinogen, when there was no morphological evidence of dysplasia.The average number of the GGT-positive foci in each experimentalperiod was found to increase with time. Even though the majorityof the foci were small, consisting of only a single cell ora small group of cells, a few larger GGT-positive lesions werenoted, particularly in the later period of the experiment. Atotal of 66 grossly visible neoplasms were found. Thirty-sevenof these were submitted for GGT staining. Thirty-two (86.5%)of these showed patchy GGT activity, primarily in the superficialepithelial cells and/or the keratin. In the non-neoplastic epithelium,the GGT staining could involve any or all layers of cells. GGTactivity was not detected in untreated or mineral oil-treatedmucosa. The results of this study support the hypothesis thatGGT activity may label potential precursors for the developmentof squamous cell carcinomas. 相似文献
2.
Hoon-Chul Kang Ji Won Kwon Young Mock Lee Heung Dong Kim Hong Jin Lee Si Houn Hahn 《Child's nervous system》2007,23(11):1301-1307
OBJECTIVES: This study sought to characterize epileptic phenotypes in children with nonspecific mitochondrial disease (MD) and to evaluate MD diagnostic approaches. METHODS: A retrospective analysis of the medical, electroencephalogram, and laboratory records of 142 patients with epilepsy was performed. The patients were evaluated for MD, and 124 patients were included in the final cohort. The MD criteria used included an oral glucose lactate stimulation test (OGLST) and urine organic acid/plasma amino acid (UOA/PAA) assays as metabolic indicators of modified Walker criteria, as suggested by Bernier et al. (Neurology 59:1406-1411, 2002). RESULTS: Twenty-two patients were classified as having definite MD (9), probable MD (5), possible MD (6), or pyruvate dehydrogenase (PDH) deficiency (3), including one patient which showed a respiratory chain (RC) defect and PDH deficiency. Seven out of eight patients in whom significant RC defects were observed showed complex I defects. In 14 patients, epileptic seizures start at infantile ages. Of 17 patients who substantially presented generalized seizures, 4 patients started with partial seizures. Five patients consistently presented only partial seizures. The OGLST and UOA/PAA assays were useful for a more precise diagnosis of MD, although low positive predictive value of the OGLST was regrettable. No patient was classified as definite MD by Walker's original criteria, but the use of our revised MD criteria resulted in the classification of nine additional patients as definite MD. CONCLUSIONS: MD manifested considerable diverse epileptic phenotypes and should be considered in the differential diagnosis of epilepsy in children with unexplained encephalomyopathy and progressive and fluctuating clinical courses. 相似文献
3.
Benign intracranial hypertension and recombinant growth hormone therapy in Australia and New Zealand
PA Crock JD McKenzie AM Nicoll NJ Howard W Cutfield LK Shield G Byrne 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(4):381-386
Benign intracranial hypertension (BIH) is reported in three children from Australia and one from New Zealand, who were being treated with recombinant human growth hormone (rhGH). Three males and one female, aged between 10.5 and 14.2 y, developed intracranial hypertension within 2 weeks to 3 months of starting treatment. A national database, OZGROW, has been prospectively collecting data on all 3332 children treated with rhGH in Australia and New Zealand from January 1986 to 1996. The incidence of BIH in children treated with growth hormone (GH) is small, 1.2 per 1000 cases overall, but appears to be greater with biochemical GHD (<10IUml -1 ), i.e. 6.5/1000 (3 in 465 cases), relative risk 18.4, 95% confidence interval 1.9-176.1, than in all other children on the database. The incidence in patients with Turner's syndrome was 2.3/1000 (1 in 428 cases). No cases in patients with partial GHD (10–20 IUml -1 ) or chronic renal failure were identified. Possible causative mechanisms are discussed. The authors'practice is now to start GH replacement at less than the usual recommended dose of 14IUm-2 week-1 in those children considered to be at high risk of developing BIH. Ophthalmological evaluation is recommended for children before and during the first few months following commencement of rhGH therapy and is mandatory in the event of peripheral or facial oedema, persistent headaches, vomiting or visual symptoms. The absence of papilledema does not exclude the diagnosis. 相似文献
4.
HIPDM single photon emission computed tomography brain imaging in partial onset secondarily generalized tonic-clonic seizures 总被引:3,自引:3,他引:0
HIPDM-Single photon emission computed tomography brain imaging was performed during interictal and ictal stages in three patients with complex partial seizures and secondarily generalized tonic-clonic seizures. In all three patients, interictal studies demonstrated decreased regional cerebral perfusion (rCP) and ictal studies showed increased rCP in the epileptogenic region. The demonstration of focal hyperperfusion by SPECT performed during secondarily generalized tonic-clonic seizures suggests that rCP in the epileptic focus remains higher than in other cerebral regions during immediate postictal stages, even in secondarily generalized seizures. 相似文献
5.
In a prospective, randomized, double-blind study, 49 patients underwent lumbar myelography using iotrol (24 patients) or metrizamide (25 patients). The diagnostic imaging adequacy of iotrol was comparable with that of metrizamide. After iotrol myelography, adverse reactions were fewer, less severe, and of shorter duration than were those following metrizamide myelography. Thirteen of 24 patients (54%) receiving iotrol reported some adverse reactions compared with 24 of 25 patients (96%) receiving metrizamide. Five moderate and one severe adverse reaction occurred in the group receiving iotrol. Fourteen moderate and eight severe adverse reactions occurred in the group receiving metrizamide. Thirty-eight patients underwent electroencephalography both before and after myelography (19 iotrol and 19 metrizamide). None of the EEGs obtained after iotrol myelography changed from baseline, while seven of the EEGs obtained after metrizamide myelography showed changes from baseline. Iotrol was judged superior to metrizamide as a contrast medium in this patient population. 相似文献
6.
7.
8.
9.
臂丛神经根性损伤膈神经移位术对青壮年患者早期呼吸功能的影响 总被引:1,自引:1,他引:0
目的研究臂丛神经损伤膈神经移位术对青壮年患者早期呼吸功能的影响.方法对16例接受膈神经移位治疗的患者,在术前、术后(10 d)进行肺功能指标的比较,同时定期进行门诊随访,观察呼吸系统自觉症状程度.结果13例术后出现了不同程度的供氧不足症状,16例全部出现一侧膈肌抬高,术后第10天肺活量(VC)、肺活量预计值百分数(VC%)分别比术前减少37.98%和26.88%,两者差异有统计学意义(tvc=11.532、tvc%=0,P<0.01).其它项目如残气量(RV)较术前轻度下降,肺总量(TLC)下降值达到术前肺总量的36.49%,残气量/肺总量比值(RV/TLC%)较术前上升了4.75%,上述各指标的差值均有统计学意义.1 s用力呼气量/用力肺活量比值(FEV1/FVC)和术前比基本无改变,但其差值有统计学意义.膈神经移位右侧(10例)与左侧(6例)术前、术后肺活量比较差异有统计学意义.术后随访8个月~2年,所有患者均无明显呼吸困难和胸闷等症状.结论膈神经移位术后对青壮年患者肺容量有较大的丧失,肺通气功能减弱和小气道阻力增加,但其丧失程度在机体自身代偿耐受范围内,不会导致急剧发生的严重呼吸功能障碍.建议对右侧臂丛神经根性损伤的患者,术前进行严格的肺、心功能检查,避免发生较为严重的并发症. 相似文献
10.