全文获取类型
收费全文 | 383158篇 |
免费 | 25075篇 |
国内免费 | 2835篇 |
专业分类
耳鼻咽喉 | 5277篇 |
儿科学 | 8294篇 |
妇产科学 | 10124篇 |
基础医学 | 53742篇 |
口腔科学 | 11845篇 |
临床医学 | 30443篇 |
内科学 | 79498篇 |
皮肤病学 | 8679篇 |
神经病学 | 27689篇 |
特种医学 | 14082篇 |
外国民族医学 | 82篇 |
外科学 | 61185篇 |
综合类 | 9964篇 |
现状与发展 | 1篇 |
一般理论 | 64篇 |
预防医学 | 17634篇 |
眼科学 | 9479篇 |
药学 | 31365篇 |
1篇 | |
中国医学 | 2196篇 |
肿瘤学 | 29424篇 |
出版年
2021年 | 2682篇 |
2019年 | 2804篇 |
2018年 | 4614篇 |
2017年 | 3515篇 |
2016年 | 3606篇 |
2015年 | 4100篇 |
2014年 | 5795篇 |
2013年 | 7503篇 |
2012年 | 10269篇 |
2011年 | 10426篇 |
2010年 | 6308篇 |
2009年 | 5951篇 |
2008年 | 9662篇 |
2007年 | 10499篇 |
2006年 | 10441篇 |
2005年 | 9487篇 |
2004年 | 9007篇 |
2003年 | 8743篇 |
2002年 | 8448篇 |
2001年 | 28406篇 |
2000年 | 28925篇 |
1999年 | 23837篇 |
1998年 | 5237篇 |
1997年 | 4309篇 |
1996年 | 3893篇 |
1995年 | 3533篇 |
1994年 | 3167篇 |
1993年 | 2884篇 |
1992年 | 16141篇 |
1991年 | 14912篇 |
1990年 | 14240篇 |
1989年 | 14053篇 |
1988年 | 12672篇 |
1987年 | 12129篇 |
1986年 | 11163篇 |
1985年 | 10388篇 |
1984年 | 6959篇 |
1983年 | 5621篇 |
1982年 | 2736篇 |
1979年 | 5510篇 |
1978年 | 3385篇 |
1977年 | 2990篇 |
1975年 | 2663篇 |
1974年 | 3075篇 |
1973年 | 2873篇 |
1972年 | 2838篇 |
1971年 | 2787篇 |
1970年 | 2519篇 |
1969年 | 2557篇 |
1968年 | 2266篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
A. Zampieron M. Elseviers P. Ormandy H. Vlaminck J.‐Y. De Vos T. Kafkia E. Lindley M. Harrington 《Journal of Renal Care》2006,32(1):14-19
This paper describes a study to capture the key roles and activities of nephrology nurses across different countries in Europe. The concept of the study and the need to clarify the activities of the nephrology nurse arose as part of a larger study to develop the European Practice Database (EPD) (1). The Research Board (EDTNA/ERCA) needed to identify key questions that would detect significant differences in the role and responsibilities of nephrology nurses in different countries and monitor the evolution over time of nephrology nursing practice in Europe. It was therefore appropriate to devise a separate small study to generate evidence based questions for the EPD and confirm the reliability and usefulness of the information captured. 相似文献
72.
Lalia Y. Ibrahim Krank P. DiFilippo Geremy E. Steed Manuel D. Cerqueira 《Journal of nuclear cardiology》2006,13(6):855-866
Conclusion Several quality-control measures take place before (patient and camera preparation) and during SPECT acquisition to achieve
high-quality images. Not uncommonly, technologists and physicians are left with suboptimal images that have to be addressed
to reach the “right answer” for patient diagnosis and hence management. In many cases patients may be reimaged, especially
if the problem is detected early, but in other cases either the patient has left the nuclear laboratory or there is an inevitable
problem that, even with reimaging, will not be resolved. In these situations the technologist and physician have to seek the
available techniques to obtain the best images possible. These resources are discussed in this issue as an aid in quality
control to obtain the best possible images. 相似文献
73.
Salvage of a failed valgus osteotomy for nonunion
of an unstable pertrochanteric fracture is reported.
A valgus intertrochanteric osteotomy was performed for a
failed sliding hip screw fixation of an unstable
pertrochanteric fracture at another institution. Four months
following osteotomy, the fracture was still un-united with
two distal screws of the hip plate broken and a coxa vara
deformity. Reconstruction was performed with a nine-hole
95° angle blade plate and cancellous bone graft, because the
insufficient fixation of the distal fragment was considered to
be the main reason for failure. The osteotomy was healed at
six months post-surgery and the patient reported complete
resolution of symptoms. Intertrochanteric valgus osteotomy
is an effective procedure for mal-union and non-union of
pertrochanteric fracture but stable fixation is required for a
good result. The blade of the angle plate offers good purchase
of the proximal fragment and secures it under rotational
and bending stresses. We recommend that distal fragments
should be fixed with at least seven cortices for this
type of osteotomy. 相似文献
74.
75.
Zinc sulfate addition to glass-ionomer-based cements: influence on physical and antibacterial properties, zinc and fluoride release. 总被引:5,自引:0,他引:5
Prudencio W R Osinaga Rosa Helena M Grande Rafael Y Ballester Maria Regina L Simionato Célia Regina M Delgado Rodrigues Antonio Muench 《Dental materials》2003,19(3):212-217
OBJECTIVES: The aim of this study is to evaluate the effect of ZnSO(4) addition to a conventional glass ionomer and a resin-modified glass ionomer on solubility, flexural strength, zinc and fluoride (F) release, and Streptococcus mutans growth inhibition. METHODS: 5 or 10% ZnSO(4) was added to Vitremer and Ketac-Fil powders. Solubility test was performed based on ISO 7489. Flexural strength was determined by 3-point bending test based on ISO 4049. Zn release/uptake was determined by atomic emission spectrometry; F release/uptake was measured using a F-specific electrode. Both release measurements were performed for 15 d before and 15 d after recharging. Antibacterial test was conducted according to agar plate methods against S. mutans, by measuring the inhibition halos in 1-h and 15-d specimens. Data were analyzed by ANOVA. RESULTS: Solubility increased with higher ZnSO(4) content, but remained below the ISO 7489 limit. Flexural strength was not affected by ZnSO(4) addition, and Vitremer performed better than Ketac-Fil. The control materials released no zinc. Vitremer with 10% ZnSO(4) released the highest amount of zinc. Fluoride release was similar for Ketac-Fil and Vitremer. In both cases, the highest amounts were released in the first 24 h. The growth inhibition halo of S. mutans was similar for both materials with highest content of ZnSO(4) and occurred only with 1-h specimens. SIGNIFICANCE: Zinc addition decreased microorganisms growth and improved fluoride release, without significantly affecting the materials' flexural strength and solubility. 相似文献
76.
小颗粒致密低密度脂蛋白氧化特性及对血管内皮细胞脂质过氧化的影响 总被引:6,自引:1,他引:5
了解小颗粒致密低密度脂蛋白中抗氧化维生素含量、氧化特性 ,探讨其对血管内皮细胞脂质过氧化的影响。采用二次密度梯度超速离心的方法分离制备小颗粒致密低密度脂蛋白 ,高压液相色谱测定其抗氧化物质维生素A、E和 β 胡萝卜素 ;连续监测小颗粒致密低密度脂蛋白在 2 34nm的吸光度以测定其氧化敏感曲线 ;在血管内皮培养液中分别加入不同浓度的小颗粒致密低密度脂蛋白 ,培养后测定培养液丙二醛的浓度。实验成功分离小颗粒致密低密度脂蛋白 ,与大而轻低密度脂蛋白相比 ,维生素A、E和 β 胡萝卜素等抗氧化物质及总抗氧化能力明显减少 ,只有大而轻低密度脂蛋白的 6 5 %、39%和 2 4 % ,故小颗粒致密低密度脂蛋白氧化的延迟时间只有大而轻低密度脂蛋白的 37.5 % ,但硫代巴比妥酸反应物质值及氧化速率分别是大而轻低密度脂蛋白的 1 .7倍和 1 .2 8倍 ;培养液中丙二醛含量随加入脂蛋白的浓度和作用时间而增高 ,2 4h时小颗粒致密低密度脂蛋白 5 0mg组、1 0 0mg组、1 5 0mg组与相同剂量大而轻低密度脂蛋白组比较丙二醛显著增高 (P <0 .0 5 )。上述结果提示 :小颗粒致密低密度脂蛋白中抗氧化物质及抗氧化能力下降 ,氧化敏感性增高 ,并促进内皮细胞过氧化损伤 相似文献
77.
Abstract: The current study examined the extent to which mothers, fathers, teachers, and teenage friends influenced Latino adolescents’ academic motivation. Using path analysis, separate models were tested for 154 Latino boys and 156 Latina girls. Findings indicated that mothers’ and teachers’ academic support were positively related to adolescent girls’ academic motivation, and fathers’ and teachers’ academic support were positively related to adolescent boys’ academic motivation. The salience of teachers’ support, possible reasons for gender differences, and implications for future research are discussed. 相似文献
78.
P E Santos E Piontelli Y R Shea M L Galluzzo S M Holland M E Zelazko S D Rosenzweig 《Medical mycology》2006,44(8):749-753
Infections due to Penicillium species other than P.marneffei are rare. We identified a boy with X-linked chronic granulomatous disease (X-CGD) with a pulmonary nodule and adjacent rib osteomyelitis caused by Penicillium piceum. The only sign of infection was an elevated sedimentation rate. P. piceum was isolated by fine needle aspirate and from excised infected tissues. Surgical removal and one year of voriconazole treatment were very well tolerated and led to complete recovery. Microbiological, microscopic and molecular studies support the fungal diagnosis. P. piceum should be considered as a relevant pathogen in immunocompromised patients. 相似文献
79.
F. Spöler M. Först Y. Marquardt D. Hoeller H. Kurz H. Merk F. Abuzahra 《Skin research and technology》2006,12(4):261-267
BACKGROUND: Three dimensional skin equivalents are widely used in dermatopharmacological and toxicological studies and as autologous transplants in wound healing. In pharmacology, there is tremendous need for monitoring the response of engineered skin equivalents to external treatment. Transplantation of skin equivalents for wound healing requires careful verification of their quality prior to transplantation. Optical coherence tomography (OCT) is a non-contact, non-destructive imaging technique for living tissues offering the potential to fulfill these needs. This work presents an analysis of OCT for high-resolution monitoring of skin equivalents at different stages during the culture process. METHODS: We developed a high-resolution OCT imaging setup based on a commercially available OCT system. A broadband femtosecond laser light source replaces the original superluminescence diode. Tomograms of living skin equivalents were recorded with an axial resolution of 3 mum and correlated with histology and immunofluorescence images. Comparison with standard low-resolution OCT is presented to emphasize the advantages of high-resolution OCT for this application. RESULTS: OCT is particularly able to distinguish between different layers of skin equivalents including stratum corneum, epidermal and dermal layer as well as the basement membrane zone. The high-resolution OCT scans correlate closely with two key benchmarks, histology and immunofluorescence imaging. CONCLUSIONS: This study clearly demonstrates the benefits of high-resolution OCT for identifying living tissue structure and morphology. Compared with the current gold standard histology, OCT offers non-destructive tissue imaging, enabling high-resolution evaluation of living tissue morphology and structure as it evolves. 相似文献
80.
H J Kim C H Kang Y T Kim S-W Sung J H Kim S M Lee C-G Yoo C-T Lee Y W Kim S K Han Y-S Shim J-J Yim 《The European respiratory journal》2006,28(3):576-580
Although surgical lung resection could improve prognosis in some patients with multidrug-resistant tuberculosis (MDR-TB), there are no reports on the optimal candidates for this surgery. The aim of the present study was to elucidate the prognostic factors for surgery in patients with MDR-TB. Patients who underwent lung resection for the treatment of MDR-TB between March 1993 and December 2004 were included in the present study. Treatment failure was defined as greater than or equal to two of the five cultures recorded in the final 12 months of treatment being positive, any one of the final three cultures being positive, or the patient having died during treatment. The variables that affected treatment outcomes were identified through univariate and multivariate logistic regression analysis. In total, 79 patients with MDR-TB were included in the present study. The treatment outcomes of 22 (27.8%) patients were classified as failure. A body mass index <18.5 kg x m(-2), primary resistance, resistance to ofloxacin and the presence of a cavitary lesion beyond the range of the surgical resection were associated with treatment failure. Low body mass index, primary resistance, resistance to ofloxacin and cavitary lesions beyond the range of resection are possible poor prognostic factors for surgical lung resection in multidrug-resistant tuberculosis patients. 相似文献