全文获取类型
收费全文 | 324360篇 |
免费 | 34096篇 |
国内免费 | 285篇 |
出版年
2018年 | 3386篇 |
2017年 | 3107篇 |
2016年 | 4607篇 |
2015年 | 6481篇 |
2014年 | 7033篇 |
2013年 | 10098篇 |
2012年 | 11169篇 |
2011年 | 11083篇 |
2010年 | 7241篇 |
2009年 | 6738篇 |
2008年 | 9518篇 |
2007年 | 9595篇 |
2006年 | 9079篇 |
2005年 | 9094篇 |
2004年 | 9030篇 |
2003年 | 8430篇 |
2002年 | 7866篇 |
2001年 | 12952篇 |
2000年 | 12928篇 |
1999年 | 10294篇 |
1998年 | 3772篇 |
1997年 | 3971篇 |
1996年 | 3902篇 |
1995年 | 3544篇 |
1994年 | 3493篇 |
1993年 | 3502篇 |
1992年 | 8617篇 |
1991年 | 8515篇 |
1990年 | 8151篇 |
1989年 | 8079篇 |
1988年 | 7457篇 |
1987年 | 7153篇 |
1986年 | 6547篇 |
1985年 | 6709篇 |
1984年 | 5630篇 |
1983年 | 4708篇 |
1982年 | 3657篇 |
1981年 | 3422篇 |
1980年 | 3202篇 |
1979年 | 5315篇 |
1978年 | 4110篇 |
1977年 | 3978篇 |
1976年 | 3653篇 |
1975年 | 4049篇 |
1974年 | 4429篇 |
1973年 | 4350篇 |
1972年 | 3861篇 |
1971年 | 3607篇 |
1970年 | 3221篇 |
1969年 | 3158篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Anne F Mannion Stephane Kämpfen Urs Munzinger Ines Kramers-de Quervain 《Arthritis research & therapy》2009,11(5):R139-13
Introduction
Patient's expectations are variably reported to influence self-rated outcome and satisfaction after medical treatment; this prospective study examined which of the following was the most important unique determinant of global outcome/satisfaction after total knee arthroplasty (TKA): baseline expectations; fulfilment of expectations; or current symptoms and function. 相似文献53.
Tamar F Brionez Shervin Assassi John D Reveille Thomas J Learch Laura Diekman Michael M Ward John C Davis Jr Michael H Weisman Perry Nicassio 《Arthritis research & therapy》2009,11(6):R182-9
Introduction
Functional status is an integral component of health-related quality of life in patients with ankylosing spondylitis (AS). The purpose of this study was to investigate the role of psychological variables in self-reported functional limitation in patients with AS, while controlling for demographic and medical variables. 相似文献54.
55.
56.
F. L. Laksmana P. J. A. Hartman Kok H. Vromans H. W. Frijlink K. Van der Voort Maarschalk 《AAPS PharmSciTech》2009,10(3):732-742
Next to the coating formulation, process conditions play important roles in determining coating quality. This study aims to
develop an operational window that separates layering from agglomeration regimes and, furthermore, the one that leads to the
best coating quality in a fluidized bed coater. The bed relative humidity and the droplet size of the coating aerosol were
predicted using a set of engineering models. The coating quality was characterized using a quantitative image analysis method,
which measures the coating thickness distribution, the total porosity, and the pore size in the coating. The layering regime
can be achieved by performing the coating process at a certain excess of the viscous Stokes number (ΔSt
v). This excess is dependent on the given bed relative humidity and droplet size. The higher the bed relative humidity, the
higher is the ΔSt
v required to keep the process in the layering regime. Further, it is shown that using bed relative humidity and droplet size
alone is not enough to obtain constant coating quality. The changes in bed relative humidity and droplet size have been identified
to correlate to the fractional area of particles sprayed per unit of time. This parameter can effectively serve as an additional
parameter to be considered for a better control on the coating quality. High coating quality is shown to be achieved by performing
the process close to saturation and spraying droplets small enough to obtain high spraying rate, but not too small to cause
incomplete coverage of the core particles. 相似文献
57.
David A. Dik Daniel R. Marous Jed F. Fisher 《Critical reviews in biochemistry and molecular biology》2017,52(5):503-542
The lytic transglycosylases (LTs) are bacterial enzymes that catalyze the non-hydrolytic cleavage of the peptidoglycan structures of the bacterial cell wall. They are not catalysts of glycan synthesis as might be surmised from their name. Notwithstanding the seemingly mundane reaction catalyzed by the LTs, their lytic reactions serve bacteria for a series of astonishingly diverse purposes. These purposes include cell-wall synthesis, remodeling, and degradation; for the detection of cell-wall-acting antibiotics; for the expression of the mechanism of cell-wall-acting antibiotics; for the insertion of secretion systems and flagellar assemblies into the cell wall; as a virulence mechanism during infection by certain Gram-negative bacteria; and in the sporulation and germination of Gram-positive spores. Significant advances in the mechanistic understanding of each of these processes have coincided with the successive discovery of new LTs structures. In this review, we provide a systematic perspective on what is known on the structure–function correlations for the LTs, while simultaneously identifying numerous opportunities for the future study of these enigmatic enzymes. 相似文献
58.
Daw-Yang Hwang Stefan Kohl Xueping Fan Asaf Vivante Stefanie Chan Gabriel C. Dworschak Julian Schulz Albertien M. van Eerde Alina C. Hilger Heon Yung Gee Tracie Pennimpede Bernhard G. Herrmann Glenn van de Hoek Kirsten Y. Renkema Christoph Schell Tobias B. Huber Heiko M. Reutter Neveen A. Soliman Natasa Stajic Radovan Bogdanovic Elijah O. Kehinde Richard P. Lifton Velibor Tasic Weining Lu Friedhelm Hildebrandt 《Human genetics》2015,134(8):905-916
59.
60.
Talita Signoreti Graziano Maria Claudia Cuzzullin Gilson Cesar Franco Humberto Osvaldo Schwartz-Filho Eduardo Dias de Andrade Francisco Carlos Groppo Karina Cogo-Müller 《PloS one》2015,10(5)
Statins are important lipid-lowering agents with other pleiotropic effects. Several studies have explored a possible protective effect of statins to reduce the morbidity and mortality of many infectious diseases. Staphylococcus aureus is one of the main pathogens implicated in nosocomial infections; its ability to form biofilms makes treatment difficult. The present study observed the MIC of atorvastatin, pravastatin and simvastatin against S. aureus, Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecalis. Simvastatin was the only agent with activity against clinical isolates and reference strains of methicilin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). Thus, the effects of simvastatin on the growth, viability and biofilm formation of S. aureus were tested. In addition, a possible synergistic effect between simvastatin and vancomycin was evaluated. Simvastatin’s MIC was 15.65 µg/mL for S. aureus 29213 and 31.25 µg/mL for the other strains of S. aureus. The effect of simvastatin was bactericidal at 4xMIC and bacteriostatic at the MIC concentration. No synergistic effect was found between simvastatin and vancomycin. However, the results obtained against S. aureus biofilms showed that, in addition to inhibiting adhesion and biofilm formation at concentrations from 1/16xMIC to 4xMIC, simvastatin was also able to act against mature biofilms, reducing cell viability and extra-polysaccharide production. In conclusion, simvastatin showed pronounced antimicrobial activity against S. aureus biofilms, reducing their formation and viability. 相似文献