全文获取类型
收费全文 | 94757篇 |
免费 | 7218篇 |
国内免费 | 240篇 |
专业分类
耳鼻咽喉 | 734篇 |
儿科学 | 2658篇 |
妇产科学 | 1743篇 |
基础医学 | 13035篇 |
口腔科学 | 2129篇 |
临床医学 | 9976篇 |
内科学 | 19935篇 |
皮肤病学 | 1273篇 |
神经病学 | 9297篇 |
特种医学 | 3222篇 |
外国民族医学 | 2篇 |
外科学 | 13061篇 |
综合类 | 1530篇 |
一般理论 | 97篇 |
预防医学 | 8452篇 |
眼科学 | 2358篇 |
药学 | 6545篇 |
3篇 | |
中国医学 | 118篇 |
肿瘤学 | 6047篇 |
出版年
2023年 | 422篇 |
2022年 | 523篇 |
2021年 | 1651篇 |
2020年 | 1014篇 |
2019年 | 1638篇 |
2018年 | 2017篇 |
2017年 | 1519篇 |
2016年 | 1629篇 |
2015年 | 1916篇 |
2014年 | 2825篇 |
2013年 | 4034篇 |
2012年 | 6309篇 |
2011年 | 6542篇 |
2010年 | 3600篇 |
2009年 | 3259篇 |
2008年 | 5948篇 |
2007年 | 6484篇 |
2006年 | 6434篇 |
2005年 | 6180篇 |
2004年 | 5954篇 |
2003年 | 5417篇 |
2002年 | 5335篇 |
2001年 | 1095篇 |
2000年 | 901篇 |
1999年 | 1102篇 |
1998年 | 1178篇 |
1997年 | 990篇 |
1996年 | 874篇 |
1995年 | 862篇 |
1994年 | 721篇 |
1993年 | 679篇 |
1992年 | 747篇 |
1991年 | 760篇 |
1990年 | 670篇 |
1989年 | 587篇 |
1988年 | 655篇 |
1987年 | 556篇 |
1986年 | 568篇 |
1985年 | 594篇 |
1984年 | 631篇 |
1983年 | 571篇 |
1982年 | 588篇 |
1981年 | 594篇 |
1980年 | 548篇 |
1979年 | 472篇 |
1978年 | 460篇 |
1977年 | 406篇 |
1976年 | 325篇 |
1975年 | 293篇 |
1974年 | 321篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
51.
52.
53.
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
54.
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
55.
56.
Jeff Anglen Peter Steven Apostoles Gordon Christensen Barry Gainor Joel Lane 《Journal of orthopaedic research》1996,14(2):251-254
We examined the efficacy of various irrigation solutions delivered through a power irrigator to remove bacteria from three different surfaces. Titanium, stainless-steel, and cortical bone surfaces were coated with three different bacterial species: Staphylococcus aureus, Pseudomonas aeruginosa, and Staphylococcus epidermidis. They were then irrigated with 1 L of fluid delivered by jet lavage. The fluids tested were normal saline and solutions of bacitracin, neomycin, and soap. One set of specimens was not irrigated, as a control. After irrigation, the specimens were sonicated to remove residual bacteria, and the sonicate was quantitatively cultured to allow evaluation of the amount of residual bacteria on the surface. The results showed that removal of bacteria reflects an interaction between bacterial species, surface characteristics, and irrigation solution. Fewer bacteria were present in all the irrigation groups than in the control. Soap solution was as good as or better than any other solution at removing all three types of bacteria from all three surfaces, although not all of the pairwise comparisons were statistically significant. There was a significant advantage to soap solution over antibiotic irrigant or saline alone in removing Staphylococcus epidermidis from metallic surfaces. The use of a soap solution for irrigation seems to improve the removal of some bacteria from some surfaces in this experimental model and may represent a better type of irrigation additive. 相似文献
57.
Peter Stone MD FRNZCOG FRCOG David Cook FRNZCOG MRCOG John Hutton PhD FRNZCOG FRCOG Gordon Purdie BSc Henry Murray MD FRNZCOG MRCOG Lauren Harcourt MPP BA 《The Australian & New Zealand journal of obstetrics & gynaecology》1995,35(1):32-37
Summary: This is the first report of the largest study of blood pressure measurement in pregnancy in a New Zealand population using standardized definitions and methodology. Over 3,800 women who delivered in an 8-month period in the Wellington region were included in the study. Blood pressure measurement and the presence of oedema and proteinuria were recorded from booking until delivery and in the puerperium. Only 2.7% of women were unable to be contacted after delivery for details on outcomes. The results established normal ranges for blood pressure throughout pregnancy. The data show that Mood pressure greater than 140/90 until 35 weeks' gestation is outside 2 standard deviations at all gestations and justifies using these measurements as the definition of hypertension in pregnancy. The fall in blood pressure in the 2nd trimester was less than 1 mm Ffg per week in both the systolic and diastolic pressures. This fall was smaller than previously recorded in other studies. Gestational hypertension was the commonest blood pressure abnormality occurring in 15.2% of the population. This represented 69% of the pregnant women with a hypertensive disorder. The overall incidence of both gestational hypertension and preeclampsia was 18.5% which is higher than reported in other parts of the world. In this study obesity was significantly associated with hypertensive disorders in pregnancy. An arm circumference of >33 cm, one of the measurements of obesity, was found in 6.8% of the study population. Even after the effect of arm circumference was taken into account, hypertensive disorders were also more common in Pacific Island women. Ankle oedema was significantly associated with the development of both gestational hypertension and preeclampsia but the incidence of oedema was noted in only 11.9% of the subjects. 相似文献
58.
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
59.
60.