收费全文 | 40499篇 |
免费 | 2662篇 |
国内免费 | 1016篇 |
耳鼻咽喉 | 104篇 |
儿科学 | 605篇 |
妇产科学 | 335篇 |
基础医学 | 5380篇 |
口腔科学 | 653篇 |
临床医学 | 2804篇 |
内科学 | 4644篇 |
皮肤病学 | 243篇 |
神经病学 | 3870篇 |
特种医学 | 1038篇 |
外国民族医学 | 2篇 |
外科学 | 1550篇 |
综合类 | 3222篇 |
现状与发展 | 2篇 |
预防医学 | 4095篇 |
眼科学 | 153篇 |
药学 | 10287篇 |
12篇 | |
中国医学 | 3697篇 |
肿瘤学 | 1481篇 |
2024年 | 124篇 |
2023年 | 587篇 |
2022年 | 1130篇 |
2021年 | 1396篇 |
2020年 | 1268篇 |
2019年 | 1243篇 |
2018年 | 1220篇 |
2017年 | 1322篇 |
2016年 | 1245篇 |
2015年 | 1191篇 |
2014年 | 2026篇 |
2013年 | 3240篇 |
2012年 | 1800篇 |
2011年 | 2213篇 |
2010年 | 1505篇 |
2009年 | 1772篇 |
2008年 | 1773篇 |
2007年 | 1747篇 |
2006年 | 1488篇 |
2005年 | 1320篇 |
2004年 | 1142篇 |
2003年 | 1045篇 |
2002年 | 922篇 |
2001年 | 879篇 |
2000年 | 664篇 |
1999年 | 686篇 |
1998年 | 684篇 |
1997年 | 595篇 |
1996年 | 575篇 |
1995年 | 549篇 |
1994年 | 480篇 |
1993年 | 455篇 |
1992年 | 460篇 |
1991年 | 420篇 |
1990年 | 394篇 |
1989年 | 399篇 |
1988年 | 355篇 |
1987年 | 342篇 |
1986年 | 332篇 |
1985年 | 453篇 |
1984年 | 405篇 |
1983年 | 281篇 |
1982年 | 355篇 |
1981年 | 280篇 |
1980年 | 290篇 |
1979年 | 209篇 |
1978年 | 222篇 |
1977年 | 162篇 |
1976年 | 195篇 |
1975年 | 79篇 |
Methods: Hybrid cells containing a fragment of human chromosome 8 in scid cells (RD13B2) were used. DNA-PK activity was measured by an in vitro assay. Immunoprecipitation of the nuclear extract was performed with an anti-Ku80 antibody. Proteins co-precipitated with Ku80 were separated by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis and detected by Western blotting using anti-heat shock protein (HSP)72 and anti-heat shock cognate protein (HSC)73 antibodies. HSC73 was overexpressed with the pcDNA3.1 vector. Short hairpin (sh)RNA was used to downregulate HSC73 and HSP72.
Results: The activity of heat-inactivated DNA-PK recovered to about 50% of control during an additional incubation at 37?°C after heat treatment at 44?°C for 15?min in the presence of cycloheximide (which inhibits de novo protein synthesis). Maximal recovery was observed within 3?h of incubation at 37?°C after heat treatment. Constitutively expressed HSC73, which folds newly synthesized proteins, reached maximal levels 3?h after heat treatment using a co-immunoprecipitation assay with the Ku80 protein. Inhibiting HSC73, but not HSP72, expression with shRNA decreased the recovery of DNA-PK activity after heat treatment.
Conclusions: These results suggest that de novo protein synthesis is unnecessary for recovery of some heat-inactivated DNA-PK. Rather, it might be reactivated by the molecular chaperone activity of HSC73, but not HSP72. 相似文献
Objective
To investigate primary care physician clinical practice patterns, barriers, and education surrounding pediatric physical activity (PA), and to compare practice patterns by discipline. 相似文献Areas covered: The many tools developed to measure disease activity in RA, from composite scores and patient-reported outcomes, to laboratory markers and imaging are discussed, with a focus on their utility in guiding therapy and assessing response. The complex issues in measuring disease activity in RA, whether in clinical trials or normal clinical practice, and in the context of national guidelines and recommendations, available time, and resources are considered.
Expert commentary: The key to effective management of RA is the rapid suppression of inflammation, ideally to remission, with maintenance of such remission. The aim is to prevent disability and maximize quality of life. Central to this is the ability to determine disease activity (potentially open to suppression) as opposed to damage (irreversible). A variety of measures are currently available, allowing better assessment of response to treatment. In the future, the development of predictive biomarkers allowing targeting of drugs may revolutionize this field and render the tools of today redundant. 相似文献
Findings: A 30-year-old man with complete paraplegia used the HAL® for 1 month (10 sessions) using his remaining muscle activity, including hip flexor and upper limb activity. Electromyography was used to evaluate muscle activity of the gluteus maximus, tensor fascia lata, quadriceps femoris, and hamstring muscles in synchronization with the Vicon motion capture system. A HAL® session included a knee extension session with the hip flexor and voluntary gait with upper limb activity. After using the HAL® for one month, the patient’s manual muscle hip flexor scores improved from 1/5 to 2/5 for the right and from 2/5 to 3/5 for the left knee, and from 0/5 to 1/5 for the extension of both knees.
Conclusion/clinical relevance: Knee extension sessions with HAL®, and hip flexor and upper-limb-triggered HAL® ambulation seem a safe and feasible option in a patient with complete paraplegia due to spinal cord injury. 相似文献