全文获取类型
收费全文 | 2326篇 |
免费 | 225篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 102篇 |
妇产科学 | 26篇 |
基础医学 | 317篇 |
口腔科学 | 101篇 |
临床医学 | 289篇 |
内科学 | 349篇 |
皮肤病学 | 50篇 |
神经病学 | 200篇 |
特种医学 | 261篇 |
外科学 | 317篇 |
综合类 | 50篇 |
一般理论 | 8篇 |
预防医学 | 151篇 |
眼科学 | 82篇 |
药学 | 129篇 |
1篇 | |
肿瘤学 | 129篇 |
出版年
2022年 | 19篇 |
2021年 | 28篇 |
2020年 | 22篇 |
2019年 | 23篇 |
2018年 | 39篇 |
2016年 | 27篇 |
2015年 | 39篇 |
2014年 | 50篇 |
2013年 | 75篇 |
2012年 | 71篇 |
2011年 | 69篇 |
2010年 | 81篇 |
2009年 | 77篇 |
2008年 | 76篇 |
2007年 | 90篇 |
2006年 | 81篇 |
2005年 | 78篇 |
2004年 | 72篇 |
2003年 | 69篇 |
2002年 | 82篇 |
2001年 | 53篇 |
2000年 | 55篇 |
1999年 | 63篇 |
1998年 | 93篇 |
1997年 | 88篇 |
1996年 | 74篇 |
1995年 | 61篇 |
1994年 | 42篇 |
1993年 | 56篇 |
1992年 | 40篇 |
1991年 | 55篇 |
1990年 | 39篇 |
1989年 | 72篇 |
1988年 | 60篇 |
1987年 | 51篇 |
1986年 | 47篇 |
1985年 | 43篇 |
1984年 | 39篇 |
1983年 | 29篇 |
1982年 | 30篇 |
1981年 | 25篇 |
1980年 | 22篇 |
1979年 | 27篇 |
1978年 | 27篇 |
1977年 | 24篇 |
1976年 | 19篇 |
1975年 | 20篇 |
1974年 | 24篇 |
1973年 | 16篇 |
1970年 | 18篇 |
排序方式: 共有2571条查询结果,搜索用时 15 毫秒
1.
Alex N. Bullock Julia Henckel Brian S. DeDecker Christopher M. Johnson Penka V. Nikolova Mark R. Proctor David P. Lane Alan R. Fersht 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(26):14338-14342
Some 50% of human cancers are associated with mutations in the core domain of the tumor suppressor p53. Many mutations are thought just to destabilize the protein. To assess this and the possibility of rescue, we have set up a system to analyze the stability of the core domain and its mutants. The use of differential scanning calorimetry or spectroscopy to measure its melting temperature leads to irreversible denaturation and aggregation and so is useful as only a qualitative guide to stability. There are excellent two-state denaturation curves on the addition of urea that may be analyzed quantitatively. One Zn2+ ion remains tightly bound in the holo-form of p53 throughout the denaturation curve. The stability of wild type is 6.0 kcal (1 kcal = 4.18 kJ)/mol at 25°C and 9.8 kcal/mol at 10°C. The oncogenic mutants R175H, C242S, R248Q, R249S, and R273H are destabilized by 3.0, 2.9, 1.9, 1.9, and 0.4 kcal/mol, respectively. Under certain denaturing conditions, the wild-type domain forms an aggregate that is relatively highly fluorescent at 340 nm on excitation at 280 nm. The destabilized mutants give this fluorescence under milder denaturation conditions. 相似文献
2.
3.
4.
Pyomyositis: characteristics at CT and MR imaging 总被引:9,自引:0,他引:9
5.
AJ Larner MRCP 《International journal of clinical practice》1994,48(5):272-274
SUMMARY A case is reported of pseudohyperphosphataemia in association with a monoclonal gammopathy of undetermined significance. 相似文献
6.
To date, despite very encouraging preclinical results, almost all phase II/III clinical neuroprotection trials in traumatic
brain injury (TBI) have failed to show any consistent improvement in outcome for TBI patients. To understand the reasons behind
such developments we need to review and evaluate the evolution of trial design as a result of our changing understanding of
the pathophysiology of brain cell death and progress of translational research from the laboratory bench to the bedside. This
paper attempts to critically appraise these neuroprotection trials, rationalize the paucity of effectiveness, review any recent
developments in the field, and try to draw some conclusions on how to move forward. 相似文献
7.
L Bullock J F Fitzgerald M R Glick R B Parks J G Schnabel B G Hancock 《American journal of hospital pharmacy》1989,46(11):2321-2325
The stability of famotidine in total parenteral nutrient (TPN) solutions and the concentrations of amino acids in the presence of famotidine were determined. Two famotidine concentrations (20 mg/L and 40 mg/L) and two amino acid concentrations (20 g/L and 42.5 g/L) were studied under the following storage conditions: refrigerated for 24 hours and then kept at room temperature (20-22 degrees C) for 24 hours, at room temperature for 48 hours, or refrigerated for seven days. Control TPN solutions were studied under the same storage conditions. TPN solutions also contained dextrose 25%, electrolytes, trace elements, and vitamins. Famotidine concentration was determined at 0, 24, and 48 hours and at seven days by high-performance liquid chromatography. Amino acid concentration was determined in the TPN solutions containing 42.5 g/L of amino acids without famotidine and with famotidine 40 mg/L under both 48-hour storage conditions. At 24 hours, all solutions retained at least 95% of the initial famotidine concentration. Seven of the eight famotidine solutions retained more than 95% of the initial famotidine concentration at 48 hours. All samples refrigerated for seven days retained more than 95% of the initial famotidine concentration. The concentration of amino acids in TPN solutions containing 42.5 g/L of amino acids was not affected by the addition of famotidine 40 mg/L under either 48-hour storage condition. Famotidine in concentrations of 20 mg/L and 40 mg/L is stable under the studied 48-hour storage conditions in TPN solutions containing amino acid concentrations of either 20 g/L or 42.5 g/L.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
8.
9.
D De AJ Kanwar S Handa 《Journal of the European Academy of Dermatology and Venereology》2006,20(7):853-859
BACKGROUND: Diagnosis of atopic dermatitis (AD) depends on clinical features because no definitive diagnostic test exists. Criteria proposed by Hanifin and Rajka (Acta Derm Venereol (Stockh) 1980; Suppl 92: 44-47) were acceptable for hospital-based studies but were found not to be suitable for field studies. A UK working party formulated clinical diagnostic criteria that could be used in both hospital and epidemiological settings. Validation studies of the criteria showed widely variable results, probably due to different clinical settings and ethnicity. AIM AND OBJECTIVE: This study was undertaken to validate Hanifin and Rajka's criteria and to assess the comparative efficacy of their criteria and the UK working party's diagnostic criteria in the diagnosis of AD in a hospital setting in North India. SUBJECTS AND METHODS: This study serially included 101 patients with AD and 48 controls of paediatric age group. The study period was from July 2003 to December 2004. RESULTS: Hanifin and Rajka's criteria (sensitivity 96%, specificity 93.75%, positive predictive value 97% (PPV) and negative predictive value (NPV) 91.84%) had a statistical advantage over the UK working party's diagnostic criteria (sensitivity 86%, specificity 95.83%, PPV 97.75% and NPV 76.67%), with a P-value < 0.005. 相似文献
10.
SUMMARY Impotence is a common symptom which can cause considerable distress to both the sufferer and his partner. The use of pharmacotherapy to improve erectile function will continue to increase as safe and effective drugs are developed. However, restoring erectile function should not be the only treatment objective. It is also essential to address personal and emotional factors in the sufferer, conflicts in his relationship with his partner, and sexual problems in his partner, all of which may be instrumental in causing or maintaining the presenting impotence. We advocate a combined approach with appropriate medical treatment and sex and couple therapy 相似文献