全文获取类型
收费全文 | 11532篇 |
免费 | 651篇 |
国内免费 | 224篇 |
专业分类
耳鼻咽喉 | 62篇 |
儿科学 | 327篇 |
妇产科学 | 284篇 |
基础医学 | 1376篇 |
口腔科学 | 233篇 |
临床医学 | 1020篇 |
内科学 | 969篇 |
皮肤病学 | 267篇 |
神经病学 | 84篇 |
特种医学 | 486篇 |
外科学 | 3112篇 |
综合类 | 1876篇 |
预防医学 | 357篇 |
眼科学 | 44篇 |
药学 | 828篇 |
3篇 | |
中国医学 | 486篇 |
肿瘤学 | 593篇 |
出版年
2024年 | 18篇 |
2023年 | 121篇 |
2022年 | 204篇 |
2021年 | 339篇 |
2020年 | 299篇 |
2019年 | 253篇 |
2018年 | 289篇 |
2017年 | 300篇 |
2016年 | 349篇 |
2015年 | 337篇 |
2014年 | 739篇 |
2013年 | 652篇 |
2012年 | 643篇 |
2011年 | 818篇 |
2010年 | 697篇 |
2009年 | 577篇 |
2008年 | 612篇 |
2007年 | 670篇 |
2006年 | 585篇 |
2005年 | 571篇 |
2004年 | 450篇 |
2003年 | 396篇 |
2002年 | 314篇 |
2001年 | 272篇 |
2000年 | 225篇 |
1999年 | 187篇 |
1998年 | 193篇 |
1997年 | 183篇 |
1996年 | 159篇 |
1995年 | 130篇 |
1994年 | 104篇 |
1993年 | 96篇 |
1992年 | 92篇 |
1991年 | 80篇 |
1990年 | 45篇 |
1989年 | 72篇 |
1988年 | 58篇 |
1987年 | 38篇 |
1986年 | 34篇 |
1985年 | 36篇 |
1984年 | 21篇 |
1983年 | 19篇 |
1982年 | 27篇 |
1981年 | 22篇 |
1980年 | 16篇 |
1979年 | 14篇 |
1978年 | 8篇 |
1977年 | 14篇 |
1976年 | 10篇 |
1973年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
11.
Nodular hyperplasia surrounding fibrolamellar carcinoma 总被引:2,自引:0,他引:2
We report a case of acetaminophen-induced liver necrosis in a 14-year-old girl. At autopsy, a 9 cm subcapsular nodule was present in the right lobe of the liver which showed distinct zonation: a central greyish white area of fibrolamellar carcinoma with a peripheral fleshy, tan-coloured rim ranging from 1 to 2 cm in thickness. This peripheral zone consisted of nodular, hyperplastic parenchyma resembling the changes seen in focal nodular hyperplasia, and stood out from the adjacent necrotic parenchyma. The sparing of this zone from the deleterious effects of acetaminophen provides indirect evidence of a predominantly arterial rather than portal blood supply to this region. The arterial supply was most probably derived from the tumour vasculature and may explain the parenchymal hyperplasia sometimes reported adjacent to a fibrolamellar carcinoma. Awareness of this phenomenon is essential when evaluating a needle biopsy, as sampling of this region may lead to a false negative diagnosis. 相似文献
12.
13.
Michael S NOBES Carol A POLLOCK Pan T HENG Michaelj FIELD 《Nephrology (Carlton, Vic.)》1995,1(4):277-283
Summary: The present studies assessed the effects of manipulating extracellular sodium (Na) concentration and Na transport on cellular hypertrophy and hyperplasia in primary culture of rat proximal tubular cells. A concentration-dependent effect on thymidine incorporation and protein content was observed with cell culture media Na concentration of 130, 140 and 150 mmol/L. This effect was independent of osmolality (matched with mannitol) and no stimulatory effect occurred if choline was substituted for Na. Cells derived from sham-operated (Sx) animals exposed to a higher media concentration of Na (150 vs 140 mmol/L) had both stimulated thymidine incorporation to 186.8 ± 35.41% (P<0.05) and enhanced cell protein content to 134.7 ± 135% (P<0.05). This effect was more pronounced in cell cultures derived from unilaterally nephrectomized (Nx) animals, being 212.8 ± 31.5% (P<0.01) for thymidine incorporation (P<0.05 vs cells from sham-operated animals grown in high Na media) and 114.4 ± 3.2% (P<0.001) for protein content (P=0.11 vs sham-operated cells grown in similar conditions). the addition of 10?4 mmol/L ethylisopropyl amiloride hydrochloride (EIPA) to Nx cells in a normal or high Na concentration media resulted in a decrease in cellular protein content to 82.6 ± 6.8% (P<0.05) and 85.5 ± 0.2% (P<0.0001) compared to respective controls. 10?4 mol/L EIPA in media supplemented with insulin-like growth factor (IGF-1) blocked the proliferative response normally seen in response to this growth factor from 156.6 ± 13.7 to 27.5 ± 3.1% (P<0.0001) compared to control. However, the presence of EIPA did not abrogate the hypertrophic response elicited by IGF-1 (cell protein content 128.1 ± 13.1% of control with IGF-1 vs 124.9 ± 12.5 with IGF-1 and EIPA; P= n.s.). Addition of 10?4 mol/L EIPA to 10% serum derived from either Sx or Nx animals blocked the growth response to the sera, limiting the cellular protein content to 76.6 ± 5.5% (P<0.0001) and 89.7 ± 4.4% (P<0.0001) and thymidine incorporation to quiescent levels of 0.2 ± 0.1% (P<0.0001) and 0.4 ± 0.1% (P<0.0001) compared to respective controls. In summary, rat renal proximal tubular cell growth is influenced by Na concentrations in the cell culture environment and inhibited in the presence of EIPA. This supports a role for altered epithelial transport in the cellular growth response to a number of stimuli. 相似文献
14.
15.
Reversible and irreversible airway inflammation and fibrosis in mice exposed to inhaled ovalbumin 总被引:1,自引:0,他引:1
Objective and design: We examined the reversibility of several changes in the lungs and airways of mice immediately after exposure to ovalbumin aerosol and after a period of recovery breathing clean air.Methods: Mice were exposed for 1, 2, 4, 6, 8, or 10 weeks, with recovery in clean air for 1–3 weeks.Results: Airway collagen content, exhaled NO, airway mucous cell hyperplasia, and lung lavage inflammatory cell content increased upon exposure to ovalbumin aerosol. All parameters except airway fibrosis decreased partially or completely to control values with recovery in clean air.Conclusions: Airway mucous cell hypertrophy and hyperplasia appear to be completely reversible after recovery in clean air, while exhaled NO and airway inflammation appear to be mostly reversible, except for persistence of lymphocytes in the lung lavage fluid. Airway fibrosis appears to be reversible when mice are exposed to ovalbumin aerosol for periods of up to 4 weeks of exposure, but becomes irreversible after 6 or more weeks of exposure.Received 30 June 2004; returned for revision 24 September 2004; accepted by J. S. Skotnicki 13 October 2004 相似文献
16.
Y. J. LIM A. B. W. YONG G. L. WARNE J. MONTALTO 《Journal of paediatrics and child health》1995,31(1):47-50
Objectives: The study was designed to assess the reliability of measurement of 24-hour urinary 17α-hydroxyprogesterone (17-OHP) by radio-immunoassay (RIA) as an alternative biochemical assessment for monitoring the treatment of congenital adrenal hyperplasia (CAH) due to 21 -hydroxylase deficiency (21 -OHD) and to assess the need for sample purification by column chromatography to improve assay specificity.
Methodology: Morning serum 17-OHP was measured using RIA and 24-hour urinary pregnanetriol using gas chromatography. Twenty-four-hour urinary 17-OHP was measured in samples from 17 prepubertal patients with CAH due to 21 -OHD, and 20 normal prepubertal children as controls. In 24 urine samples, RIA of 17-OHP was performed with and without column chromatography.
Results: There was a good correlation between 24-hour urinary 17-OHP and 24-hour urinary pregnanetriol (r = 0.962, P <0.01) and between 24-hour urinary 17-OHP and morning serum 17-OHP ( r = 0.955, P <0.01). There was no significant difference in the RIA of the urine samples with and without purification by column chromatography.
Conclusions: The measurement of 24-hour urinary 17-OHP is a reliable alternative for the biochemical monitoring of 21-OHD, and RIA specificity is unaffected by omission of column chromatography. 相似文献
Methodology: Morning serum 17-OHP was measured using RIA and 24-hour urinary pregnanetriol using gas chromatography. Twenty-four-hour urinary 17-OHP was measured in samples from 17 prepubertal patients with CAH due to 21 -OHD, and 20 normal prepubertal children as controls. In 24 urine samples, RIA of 17-OHP was performed with and without column chromatography.
Results: There was a good correlation between 24-hour urinary 17-OHP and 24-hour urinary pregnanetriol (r = 0.962, P <0.01) and between 24-hour urinary 17-OHP and morning serum 17-OHP ( r = 0.955, P <0.01). There was no significant difference in the RIA of the urine samples with and without purification by column chromatography.
Conclusions: The measurement of 24-hour urinary 17-OHP is a reliable alternative for the biochemical monitoring of 21-OHD, and RIA specificity is unaffected by omission of column chromatography. 相似文献
17.
KAMIL CAM YAVUZ AKMAN ALI KAYIKCI FERDA SENEL ALI EROL 《International journal of urology》2003,10(11):582-586
BACKGROUND: The severity of symptoms still constitutes the major indication for transurethral prostatectomy, despite the extensive utilization of medical treatments. The aim of the study presented here was to investigate the impact of doxazosin on symptoms in relation to the probability of consequent surgery in severely symptomatic patients. METHODS: Patients with an International Prostate Symptom Score (IPSS) between 18 and 35 were included in the study. The patients received 4 mg/day doxazosin, and subjective efficacy was assessed by IPSS at the first and third months. In addition, the patients were classified at the third month according to a single question regarding satisfaction with medical treatment in terms of symptom relief as 'ineffective, no change, and effective'. RESULTS: A total of 178 patients constituted the study group. Mean total symptom scores were 24, 19 and 17 at baseline, first and third months, respectively (P < 0.05). According to results of the questionnaire, 23% of the patients claimed the treatment was ineffective, and subsequently, the majority of this group (93%) underwent prostatectomy in a year. In addition, 33% of the patients reported no change in their symptoms, while 44% reported that the medication was effective. However, after 1 year, 59% and 15% of these cases underwent surgical treatment, respectively. The probability of surgery in the 'ineffective' group was significantly higher compared to the remaining groups (P < 0.05). CONCLUSION: The majority of patients with severe symptoms who were not satisfied with the medication at the 3rd month underwent surgery. This observation may provide a predictor for subsequent probability of prostatectomy. Therefore, reassessment of patients would be a cost-effective approach for the treatment of BPH in severely symptomatic patients. 相似文献
18.
目的:探讨经尿道等离子前列腺双极汽化电切术(TUPKVP)治疗前列腺增生的效果。方法:回顾性分析580例良性前列腺增生(BPH)患者行TUPKVP的临床资料。结果:中转开放手术2例,切除前列腺组织10~80 g,平均32.5 g。手术时间25~150 min,平均60 min,术中输血10例,无电切综合征(TURS)发生。术后随访2~36个月,患者最大尿流率升高,IPSS症状评分值降低,排尿通畅,疗效好,并发症少。结论:TUPKVP出血少,手术安全,疗效确切,是治疗前列腺增生的有效方法。 相似文献
19.
侯湘 《生物医学工程与临床》2005,9(3):153-154
目的鉴于MRI对组织的高分辨性能,利用该图像观察颈椎综合征患者的椎管外组织的病理状况.方法54例患者,其中男30例,女24例,分为2组.观察组44例颈椎综合征患者,对照组10例颈部外伤和三叉神经痛患者.通过常规的MRI矢状位及横轴位颈椎图像,比较两组软组织增生情况.结果与结论在颈椎综合征MRI的颈椎及上段胸椎棘突后侧,均可观察到不同程度的慢性纤维性变化,与对照组比较,有可比性.提示临床上颈椎综合征多与颈肩区筋膜炎、棘突炎相关,属于无菌性炎症,其慢性阶段,局部发生了纤维增生性改变.建议在观察分析此种病症的颈椎骨质及椎间盘改变的同时,宜重视棘突后侧的纤维性变化,有利于病理病因的研究. 相似文献
20.
M. Bryne C. Gravdahl H. S. Koppang . Kjrheim E. Dabelsteen 《The Journal of pathology》1995,175(2):237-242
Cell surface carbohydrates are involved in many cell functions such as cellular differentiation, adhesion, and invasion. A carbohydrate, sialosyl-Tn (STn), is expressed in many human carcinomas but generally not in normal epithelia. In the oral mucosa, however, STn had recently been observed on basal cell in some lesions with epithelial hyperplasia and dysplasia. The aim of this study was to carry out a systematic investigation of STn expression on epithelial basal cells in hyperplastic, ‘borderline’ malignant, and malignant head and neck lesions, to see if the expression of STn is associated specifically with hyperplastic conditions. Using the primary monoclonal antibody TKH2, normal controls did not reveal STn. STn was detected on probably post-mitotic basal cells in hyperplastic head and neck lesions and on basal cells adjacent to cancers, but not within the carcinomas. A Ki67 antibody reacted with basal cells in other locations. The most highly differentiated lesions, such as focal epithelial hyperplasia and verrucous hyperplasia, revealed a high percentage (86 per cent in both cases) of STn reactivity. The least-differentiated verrucous carcinomas (VCs) and keratoacanthomas (KAs) did not express STn, in contrast to the highly differentiated VCs and KAs. These findings indicate that STn-negative cases may have a greater malignant potential that the STn-positive cases. In conclusion, STn expressed on basal cells is possibly a marker for non-malignant conditions with altered basal cell activity and for highly differentiated verrucous carcinomas. 相似文献