全文获取类型
收费全文 | 3878篇 |
免费 | 232篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 67篇 |
儿科学 | 76篇 |
妇产科学 | 74篇 |
基础医学 | 582篇 |
口腔科学 | 83篇 |
临床医学 | 297篇 |
内科学 | 778篇 |
皮肤病学 | 56篇 |
神经病学 | 414篇 |
特种医学 | 185篇 |
外科学 | 656篇 |
综合类 | 18篇 |
预防医学 | 253篇 |
眼科学 | 72篇 |
药学 | 229篇 |
中国医学 | 5篇 |
肿瘤学 | 277篇 |
出版年
2023年 | 17篇 |
2022年 | 18篇 |
2021年 | 42篇 |
2020年 | 37篇 |
2019年 | 40篇 |
2018年 | 68篇 |
2017年 | 59篇 |
2016年 | 64篇 |
2015年 | 65篇 |
2014年 | 105篇 |
2013年 | 127篇 |
2012年 | 184篇 |
2011年 | 223篇 |
2010年 | 123篇 |
2009年 | 116篇 |
2008年 | 199篇 |
2007年 | 210篇 |
2006年 | 225篇 |
2005年 | 209篇 |
2004年 | 205篇 |
2003年 | 215篇 |
2002年 | 244篇 |
2001年 | 81篇 |
2000年 | 105篇 |
1999年 | 113篇 |
1998年 | 62篇 |
1997年 | 44篇 |
1996年 | 47篇 |
1995年 | 26篇 |
1994年 | 19篇 |
1993年 | 30篇 |
1992年 | 35篇 |
1991年 | 47篇 |
1990年 | 45篇 |
1989年 | 43篇 |
1988年 | 39篇 |
1987年 | 39篇 |
1986年 | 27篇 |
1985年 | 39篇 |
1983年 | 25篇 |
1982年 | 24篇 |
1981年 | 15篇 |
1980年 | 19篇 |
1979年 | 31篇 |
1978年 | 18篇 |
1977年 | 17篇 |
1975年 | 17篇 |
1974年 | 26篇 |
1972年 | 18篇 |
1968年 | 18篇 |
排序方式: 共有4122条查询结果,搜索用时 15 毫秒
61.
Christopher L Carroll Anita Bhandari Aaron R Zucker Craig M Schramm 《Pediatric critical care medicine》2006,7(6):527-531
OBJECTIVES: Childhood obesity contributes to a wide array of medical conditions, including asthma. There is also increasing evidence in adult patients admitted to the intensive care unit (ICU) that obesity contributes to increased morbidity and to a prolonged length of stay. We hypothesized that obesity is associated with the need for increased duration of therapy in children admitted to the ICU with status asthmaticus. DESIGN: Retrospective cohort study. SETTING: A tertiary pediatric ICU in a university-affiliated children's hospital. PATIENTS: We retrospectively examined data from all children older than 2 yrs admitted to the ICU with status asthmaticus between April 1997 and June 2004. Children were classified as normal weight (<95% weight-for-age percentile) or obese (>95% weight-for-age). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of the 209 children admitted to the ICU with asthma, 45 (22%) were obese. Compared with children of normal weight, the obese children were older (9.7 +/- 4.4 vs. 8.0 +/- 4.3 yrs, p = .02), more likely to be female (60% vs. 37%, p < .01), and more likely to have been admitted to the ICU previously (40% vs. 20%, p = .01). The obese children also had a statistically significant difference in race (more likely to be Hispanic) and in baseline asthma classification (more likely to have persistent asthma). Despite similar severity of illness at ICU admission, obese children had a significantly longer ICU length of stay (116 +/- 125 hrs vs. 69 +/- 57 hrs, p = .02) and hospital length of stay (9.8 +/- 7.0 vs. 6.5 +/- 3.4 days, p < .01). Obese children also received longer courses of supplemental oxygen, continuous albuterol, and intravenous steroids. CONCLUSIONS: Childhood obesity significantly affects the health of children with asthma. Obese children with status asthmaticus recovered more slowly from an acute exacerbation, even after adjustment for baseline asthma severity and admission severity of illness. 相似文献
62.
Kappert U Cichon R Schneider J Schramm I Schüler S 《The Annals of thoracic surgery》2000,70(5):1699-1701
A clinical case of a closed chest double-vessel total endoscopic coronary artery bypass procedure was performed using a wrist-enhanced, three-dimensional-based robotic system. A patient suffering from lesions of the left coronary artery system was effectively treated surgically without median sternotomy or minithoracotomy. This encourages optimism for introducing closed chest endoscopic bypass operations into the surgical routine for patients suffering from double-vessel coronary artery disease. 相似文献
63.
64.
65.
Eleanor Hinde Iain S. Haslam Marlon R. Schneider Ewan A. Langan Jennifer E. Kloepper Carolin Schramm Christos C. Zouboulis Ralf Paus 《Experimental dermatology》2013,22(10):631-637
The skin of most mammals is characterised by the presence of sebaceous glands (SGs), whose predominant constituent cell population is sebocytes, that is, lipid‐producing epithelial cells, which develop from the hair follicle. Besides holocrine sebum production (which contributes 90% of skin surface lipids), multiple additional SG functions have emerged. These range from antimicrobial peptide production and immunomodulation, via lipid and hormone synthesis/metabolism, to the provision of an epithelial progenitor cell reservoir. Therefore, in addition to its involvement in common skin diseases (e.g. acne vulgaris), the unfolding diversity of SG functions, both in skin health and disease, has raised interest in this integral component of the pilosebaceous unit. This practical guide provides an introduction to SG biology and to relevant SG histochemical and immunohistochemical techniques, with emphasis placed on in situ evaluation methods that can be easily employed. We propose a range of simple, established markers, which are particularly instructive when addressing specific SG research questions in the two most commonly investigated species in SG research, humans and mice. To facilitate the development of reproducible analysis techniques for the in situ evaluation of SGs, this methods review concludes by suggesting quantitative (immuno‐)histomorphometric methods for standardised SG evaluation. 相似文献
66.
Heymans Lothar Huber Martin Paeschke Norbert Palissa Harriet Keller-Stanislawski Brigitte 《Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz》2018,61(9):1088-1092
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Schulungsmaterial für Heilberufler und Patienten stellt eine wichtige Hilfe bei der sicheren Anwendung bestimmter... 相似文献
67.
68.
Diffusion parameter mapping with the combined intravoxel incoherent motion and kurtosis model using artificial neural networks at 3 T 下载免费PDF全文
Marco Bertleff Sebastian Domsch Sebastian Weingärtner Jascha Zapp Kieran O'Brien Markus Barth Lothar R. Schad 《NMR in biomedicine》2017,30(12)
Artificial neural networks (ANNs) were used for voxel‐wise parameter estimation with the combined intravoxel incoherent motion (IVIM) and kurtosis model facilitating robust diffusion parameter mapping in the human brain. The proposed ANN approach was compared with conventional least‐squares regression (LSR) and state‐of‐the‐art multi‐step fitting (LSR‐MS) in Monte‐Carlo simulations and in vivo in terms of estimation accuracy and precision, number of outliers and sensitivity in the distinction between grey (GM) and white (WM) matter. Both the proposed ANN approach and LSR‐MS yielded visually increased parameter map quality. Estimations of all parameters (perfusion fraction f, diffusion coefficient D, pseudo‐diffusion coefficient D*, kurtosis K) were in good agreement with the literature using ANN, whereas LSR‐MS resulted in D* overestimation and LSR yielded increased values for f and D*, as well as decreased values for K. Using ANN, outliers were reduced for the parameters f (ANN, 1%; LSR‐MS, 19%; LSR, 8%), D* (ANN, 21%; LSR‐MS, 25%; LSR, 23%) and K (ANN, 0%; LSR‐MS, 0%; LSR, 15%). Moreover, ANN enabled significant distinction between GM and WM based on all parameters, whereas LSR facilitated this distinction only based on D and LSR‐MS on f, D and K. Overall, the proposed ANN approach was found to be superior to conventional LSR, posing a powerful alternative to the state‐of‐the‐art method LSR‐MS with several advantages in the estimation of IVIM–kurtosis parameters, which might facilitate increased applicability of enhanced diffusion models at clinical scan times. 相似文献
69.
70.
Immucillin H, a powerful transition-state analog inhibitor of purine nucleoside phosphorylase, selectively inhibits human T lymphocytes 下载免费PDF全文
Kicska GA Long L Hörig H Fairchild C Tyler PC Furneaux RH Schramm VL Kaufman HL 《Proceedings of the National Academy of Sciences of the United States of America》2001,98(8):4593-4598
Transition-state theory has led to the design of Immucillin-H (Imm-H), a picomolar inhibitor of purine nucleoside phosphorylase (PNP). In humans, PNP is the only route for degradation of deoxyguanosine, and genetic deficiency of this enzyme leads to profound T cell-mediated immunosuppression. This study reports the biological effects and mechanism of action of Imm-H on malignant T cell lines and on normal activated human peripheral T cells. Imm-H inhibits the growth of malignant T cell leukemia lines with the induction of apoptosis. Imm-H also inhibits activated normal human T cells after antigenic stimulation in vitro. However, Imm-H did not inhibit malignant B cells, colon cancer cell lines, or normal human nonstimulated T cells, demonstrating the selective activity of Imm-H. The effects on leukemia cells were mediated by the cellular phosphorylation of deoxyguanosine and the accumulation of dGTP, an inhibitor of ribonucleotide diphosphate reductase. Cells were protected from the toxic effects of Imm-H when deoxyguanosine was absent or when deoxycytidine was present. Guanosine incorporation into nucleic acids was selectively blocked by Imm-H with no effect on guanine, adenine, adenosine, or deoxycytidine incorporation. Imm-H may have clinical potential for treatment of human T cell leukemia and lymphoma and for other diseases characterized by abnormal activation of T lymphocytes. The design of Imm-H from an enzymatic transition-state analysis exemplifies a powerful approach for developing high-affinity enzyme inhibitors with pharmacologic activity. 相似文献