全文获取类型
收费全文 | 105370篇 |
免费 | 8407篇 |
国内免费 | 224篇 |
专业分类
耳鼻咽喉 | 726篇 |
儿科学 | 3178篇 |
妇产科学 | 2114篇 |
基础医学 | 14571篇 |
口腔科学 | 2197篇 |
临床医学 | 11540篇 |
内科学 | 21231篇 |
皮肤病学 | 1515篇 |
神经病学 | 9776篇 |
特种医学 | 3617篇 |
外国民族医学 | 4篇 |
外科学 | 14367篇 |
综合类 | 1624篇 |
一般理论 | 114篇 |
预防医学 | 10550篇 |
眼科学 | 2611篇 |
药学 | 7419篇 |
1篇 | |
中国医学 | 125篇 |
肿瘤学 | 6721篇 |
出版年
2023年 | 554篇 |
2022年 | 778篇 |
2021年 | 1981篇 |
2020年 | 1148篇 |
2019年 | 1907篇 |
2018年 | 2235篇 |
2017年 | 1685篇 |
2016年 | 1846篇 |
2015年 | 2098篇 |
2014年 | 3089篇 |
2013年 | 4302篇 |
2012年 | 6794篇 |
2011年 | 6897篇 |
2010年 | 3904篇 |
2009年 | 3468篇 |
2008年 | 6273篇 |
2007年 | 6812篇 |
2006年 | 6723篇 |
2005年 | 6386篇 |
2004年 | 6147篇 |
2003年 | 5602篇 |
2002年 | 5420篇 |
2001年 | 1752篇 |
2000年 | 1600篇 |
1999年 | 1654篇 |
1998年 | 1311篇 |
1997年 | 1123篇 |
1996年 | 980篇 |
1995年 | 899篇 |
1994年 | 812篇 |
1993年 | 779篇 |
1992年 | 1155篇 |
1991年 | 1078篇 |
1990年 | 1019篇 |
1989年 | 911篇 |
1988年 | 949篇 |
1987年 | 859篇 |
1986年 | 824篇 |
1985年 | 897篇 |
1984年 | 842篇 |
1983年 | 736篇 |
1982年 | 647篇 |
1981年 | 645篇 |
1980年 | 592篇 |
1979年 | 658篇 |
1978年 | 579篇 |
1977年 | 446篇 |
1976年 | 403篇 |
1975年 | 355篇 |
1974年 | 390篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Elaina F. George Arnold Komisar Stephen C. Scharf Adrienne Ferracci Stanley Blaugrund 《The Laryngoscope》1998,108(5):627-629
A retrospective chart review of 43 patients who underwent technetium 99m (Tc-99m) sestamibi scans from June 1995 to January 1997 was performed. Only those who underwent subsequent parathyroid exploration with excision were included in the study. Twenty subjects (13 women and seven men) were included in the study. Ages ranged from 21 to 84 years (mean, 58 years). All patients had laboratory values and clinical findings consistent with primary hyperparathyroidism. Two patients had preoperative magnetic resonance imaging (MRI) scans (one patient with recurrent disease), and one had a preoperative computed tomography (CT) scan. The remaining patients had the sestamibi scan as the only preoperative localization study. There were 18 pathologic diagnoses of parathyroid adenoma and two of parathyroid hyperplasia. Sestamibi failed to correctly identify the location of the parathyroid lesion in two cases. In 18 cases the preoperative sestamibi scan correctly localized the lesion, a predictive value of 90%. We conclude that the Tc-99m sestamibi scan is an accurate preoperative tool that can be used as a single modality to localize parathyroid adenomas. 相似文献
13.
Stephen R. Thomas Ronald G. Pratt Ronald W. Millard R. C. Samaratunga Yoseph Shiferaw Leland C. Clark Richard E. Hoffmann 《Journal of magnetic resonance imaging : JMRI》1994,4(4):631-635
Oxygen-sensitive F-19 magnetic resonance imaging of perfluorocarbon compounds requires that fluorocarbon T1 changes correlate with the local Po2 and not with the composition of the surrounding aqueous phase. The influence of various bioconstituents and paramagnetic ions within the aqueous phase on the F-19 fluorocarbon phase T1 for PFC emulsions was evaluated at 0.14 and 0.66 T. T1 was measured for FC-43, perflubron, and a fluorinated surfactant. Controlled variables introduced in the aqueous phase included annex solution constituents, blood, pH changes, and Gd-DTPA. For a constant Po2, the F-19 T1s were independent of the emulsion constituents, blood concentration, and pH. For FC-43 and perflubron, F-19 T1 was independent of the Gd-DTPA concentration, while the aqueous phase T1 decreased by more than an order of magnitude. XMO-10 (smallest emulsion particle size) showed a slight decrease in F-19 T1 with increasing Gd-DTPA concentration at 0.66 T. 相似文献
14.
Sarah A. Taylor Jacqueline Benedetti David Schuller Stephen P. Richman Goronwy O. Broun Alexander Hantel 《Investigational new drugs》1993,11(2-3):227-229
Summary Twenty-two patients with recurrent or metastatic squamous cell carcinoma of the head and neck were treated with piroxantrone 150 mg/m2 intravenously every 21 days. There were no objective responses. The 95% upper confidence bound for response is 15%. Primary toxicity was hematologic. 相似文献
15.
16.
17.
Facilitated uptake of zinc into human erythrocytes. Relevance to the treatment of sickle-cell anaemia 总被引:1,自引:0,他引:1
R C Hider L Ejim P D Taylor R Gale E Huehns J B Porter 《Biochemical pharmacology》1990,39(6):1005-1012
The ability of a number of heterocyclic metal chelators to deliver zinc into red cells, to release the liganded zinc to haemoglobin and thereby cause a left shift in the oxygen dissociation curve of intact red cells has been investigated. Incubation of neutrally charged zinc-pyrone and zinc-pyridin-2-one complexes with red cells led to the rapid accumulation of zinc within cells, whereas unliganded zinc in the form of zinc acetate, zinc chloride or zinc sulphate accumulated only slowly. The rate at which zinc was delivered to red cells by pyrone and pyridin-2-one ligands increased with increasing lipid solubility of the ligands. The uptake of zinc into both normal adult and sickle red cells was associated with a dose-dependent increase in the oxygen affinity of haemoglobin. The degree of left shift in the oxygen dissociation curve following the incubation of red cells with zinc-pyrone and -pyridin-2-one complexes suggests that these complexes may find application as agents to increase the oxygen affinity of haemoglobin in sickle cell disease and thereby decrease the probability of intravascular sickling at low tissue oxygen tensions. Ethylmaltol appears to be a particularly useful agent due to its known low toxicity. 相似文献
18.
Joseph M Dhahbi Shelley X Cao Patricia L Mote Brian C Rowley John E Wingo Stephen R Spindler 《The Journal of nutrition》2002,132(1):31-37
Molecular chaperones assist in the biosynthesis and processing of proteins. Most chaperones are induced by physiological stresses. We have shown that dietary energy restriction decreases the mRNA and protein levels of many endoplasmic reticulum chaperones in the livers of mice. Here, we have investigated the response of chaperone mRNA to feeding. Control and 50% energy-restricted C3B10RF1 mice were deprived of food for 24 h, fed, and killed 0, 1.5, 5 or 12 h after feeding. Chaperone mRNAs were strongly induced as early as 1.5 h after feeding in control and energy-restricted mice. The integrated levels of these mRNA over 24 h were significantly lower in energy-restricted mice. The mRNA response to energy intake was mirrored over the course of days in the level of chaperone protein. A similar but smaller response to feeding was found in kidney and muscle. Puromycin and cycloheximide failed to inhibit the feeding response, suggesting that feeding releases chaperone expression from an unstable inhibitor. Studies with dibutyryl-cAMP- and glucagon-supplemented, normal and streptozotocin-diabetic mice suggest that glucagon and insulin may be mediators of the feeding response. Adrenalectomy enhanced the feeding induction, but dexamethasone administration had no effect. Thus, postprandial changes in insulin and glucagon may link chaperone gene expression to feeding, possibly in several tissues including liver. 相似文献
19.
M B Taylor 《Postgraduate medicine》1991,89(8):40-2, 45-7
The spectrum of acne vulgaris is wide, ranging from minor comedones to devastating nodules and cysts. Appropriate therapy requires an understanding of the various types of lesions, their pathophysiology, and the rationale for treatment. Good patient rapport and communication are important, and close follow-up is necessary until the treatment regimen has stabilized. Timely referral to a dermatologist is essential when therapy is not effective. With effort, the treatment of acne can be quite rewarding for both patient and physician. 相似文献
20.
32nd Annual Meeting of the Scandinavian Society for Psychopharmacology Copenhagen, Denmark April 10–12, 1991 Abstracts 相似文献