全文获取类型
收费全文 | 2719篇 |
免费 | 102篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 30篇 |
儿科学 | 129篇 |
妇产科学 | 57篇 |
基础医学 | 227篇 |
口腔科学 | 262篇 |
临床医学 | 190篇 |
内科学 | 551篇 |
皮肤病学 | 64篇 |
神经病学 | 160篇 |
特种医学 | 138篇 |
外科学 | 417篇 |
综合类 | 45篇 |
一般理论 | 1篇 |
预防医学 | 110篇 |
眼科学 | 182篇 |
药学 | 115篇 |
中国医学 | 12篇 |
肿瘤学 | 134篇 |
出版年
2023年 | 17篇 |
2022年 | 54篇 |
2021年 | 86篇 |
2020年 | 52篇 |
2019年 | 42篇 |
2018年 | 67篇 |
2017年 | 36篇 |
2016年 | 60篇 |
2015年 | 83篇 |
2014年 | 106篇 |
2013年 | 153篇 |
2012年 | 199篇 |
2011年 | 201篇 |
2010年 | 154篇 |
2009年 | 101篇 |
2008年 | 140篇 |
2007年 | 155篇 |
2006年 | 136篇 |
2005年 | 108篇 |
2004年 | 111篇 |
2003年 | 89篇 |
2002年 | 78篇 |
2001年 | 68篇 |
2000年 | 67篇 |
1999年 | 67篇 |
1998年 | 21篇 |
1997年 | 20篇 |
1996年 | 12篇 |
1995年 | 18篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 33篇 |
1991年 | 27篇 |
1990年 | 20篇 |
1989年 | 23篇 |
1988年 | 33篇 |
1987年 | 26篇 |
1986年 | 24篇 |
1985年 | 22篇 |
1984年 | 15篇 |
1983年 | 6篇 |
1980年 | 6篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1974年 | 8篇 |
1973年 | 4篇 |
1971年 | 5篇 |
排序方式: 共有2824条查询结果,搜索用时 15 毫秒
91.
92.
Nivedita?Shetty Lingfei?Zeng Sharad?Mangal Haichen?Nie Matthew?R.?Rowles Rui?Guo Youngwoo?Han Joon?Hyeong?Park Qi??Zhou 《Pharmaceutical research》2018,35(1):7
Purpose
This study aims to investigate the influence of different storage humidity conditions on crystallization and aerosol performance of inhalable spray dried amorphous powder formulations (Ciprofloxacin hydrochloride as the model drug).Methods
The spray dried samples were stored at 20%, 55% and 75% relative humidity (RH). Crystallinity was monitored by Powder X-ray diffraction (PXRD), and particle morphology was measured by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Aerosol performance was evaluated using a multi-stage liquid impinger (MSLI).Results
PXRD diffractograms showed the spray dried Ciprofloxacin stored at 20% RH for three weeks were amorphous; whereas those stored at 55% RH and 75% RH started crystallizing after one hour. Fine particle fraction (FPF) of the particles was improved from 28% to 42% after storage at 55% RH for three days. Such improvement was attributed to the crystallization of amorphous powders, which led to increased particle roughness and reduced particulate contact area, as visualized by SEM and quantified by AFM. A linear relationship was observed between degree of crystallinity/crystallite size and FPF (R2?=?0.94 and R2?=?0.96, respectively). However, deterioration in aerosol performance was observed after storage at 75% RH due to formation of inter-particulate liquid/solid bridges, as confirmed by SEM.Conclusions
This study provides a fundamental understanding in moisture-induced physical and aerosol instability of the spray dried powder formulations.93.
94.
95.
Krishna Poojita Vunnava Naren Shetty Kamal B Kapur 《Indian journal of ophthalmology》2020,68(12):2663
Refractive surgery has evolved from being a therapeutic correction of high refractive errors to a cosmetic correction. The expectations associated with such a surgery are enormous and one has to anticipate all possible complications and side-effects that come with the procedure and prepare accordingly. The most common amongst these is post-refractive surgery dry eye of which Meibomian gland dysfunction is a commonly associated cause. We present an understanding of various diagnostic imaging modalities that can be used for evaluating meibomian glands which can also serve as a visual aid for patient understanding. We also describe various common conditions which can silently cause changes in the gland architecture and function which are to be considered and evaluated for. 相似文献
96.
97.
Matthew P. Kosloski Krithika A. Shetty Hironao Wakabayashi Philip J. Fay Sathy V. Balu-Iyer 《The AAPS journal》2014,16(5):1038-1045
Proteolytic cleavage of factor VIII (FVIII) to activated FVIIIa is required for participation in the coagulation cascade. The A2 domain is no longer covalently bound in the resulting activated heterotrimer and is highly unstable. Aspartic acid (D) 519 and glutamic acid (E) 665 at the A1–A2 and A2–A3 domain interfaces were identified as acidic residues in local hydrophobic pockets. Replacement with hydrophobic valine (V; D519V/E665V) improved the stability and activity of the mutant FVIII over the wild-type (WT) protein in several in vitro assays. In the current study, we examined the impact of mutations on secondary and tertiary structure as well as in vivo stability, pharmacokinetics (PK), efficacy, and immunogenicity in a murine model of Hemophilia A (HA). Biophysical characterization was performed with far-UV circular dichroism (CD) and fluorescence emission studies. PK and efficacy of FVIII was studied following i.v. bolus doses of 4, 10 and 40 IU/kg with chromogenic and tail clip assays. Immunogenicity was measured with the Bethesda assay and ELISA after a series of i.v. injections. Native secondary and tertiary structure was unaltered between variants. PK profiles were similar at higher doses, but at 4 IU/kg plasma survival of D519V/E665V was improved. Hemostasis at low concentrations was improved for the mutant. Immune response was similar between variants. Overall, these results demonstrate that stabilizing mutations in the A2 domain of FVIII can improve HA therapy in vivo.KEY WORDS: efficacy, FVIII, Hemophilia A, immunogenicity, mutant 相似文献
98.
Endocan is a novel endothelium derived soluble dermatan sulfate proteoglycan. It has the property of binding to a wide range of bioactive molecules associated with cellular signaling and adhesion and thus regulating proliferation, differentiation, migration, and adhesion of different cell types in health and disease. An increase in tissue expression or serum level of endocan reflects endothelial activation and neovascularization which are prominent pathophysiological changes associated with inflammation and tumor progression. Consequently, endocan has been used as a blood-based and tissue-based biomarker for various cancers and inflammation and has shown promising results.KEY WORDS: Cancer, endocan, endothelial cell-specific molecule, proteoglycan 相似文献
99.
Ludwig Daniel R. Fraum Tyler J. Cannella Roberto Ballard David H. Tsai Richard Naeem Muhammad LeBlanc Maverick Salter Amber Tsung Allan Shetty Anup S. Borhani Amir A. Furlan Alessandro Fowler Kathryn J. 《Abdominal imaging》2019,44(6):2116-2132
Abdominal Radiology - The Liver Imaging Reporting and Data System (LI-RADS) was created to standardize the diagnostic criteria for hepatocellular carcinoma (HCC) and has undergone multiple... 相似文献
100.
Nierman WC Feldblyum TV Laub MT Paulsen IT Nelson KE Eisen JA Heidelberg JF Alley MR Ohta N Maddock JR Potocka I Nelson WC Newton A Stephens C Phadke ND Ely B DeBoy RT Dodson RJ Durkin AS Gwinn ML Haft DH Kolonay JF Smit J Craven MB Khouri H Shetty J Berry K Utterback T Tran K Wolf A Vamathevan J Ermolaeva M White O Salzberg SL Venter JC Shapiro L Fraser CM Eisen J 《Proceedings of the National Academy of Sciences of the United States of America》2001,98(7):4136-4141