全文获取类型
收费全文 | 847篇 |
免费 | 59篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 49篇 |
妇产科学 | 18篇 |
基础医学 | 118篇 |
口腔科学 | 38篇 |
临床医学 | 97篇 |
内科学 | 124篇 |
皮肤病学 | 15篇 |
神经病学 | 58篇 |
特种医学 | 48篇 |
外科学 | 104篇 |
综合类 | 12篇 |
预防医学 | 84篇 |
眼科学 | 6篇 |
药学 | 59篇 |
肿瘤学 | 95篇 |
出版年
2022年 | 5篇 |
2021年 | 7篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 10篇 |
2017年 | 17篇 |
2016年 | 14篇 |
2015年 | 15篇 |
2014年 | 20篇 |
2013年 | 22篇 |
2012年 | 41篇 |
2011年 | 44篇 |
2010年 | 33篇 |
2009年 | 28篇 |
2008年 | 24篇 |
2007年 | 48篇 |
2006年 | 27篇 |
2005年 | 29篇 |
2004年 | 38篇 |
2003年 | 38篇 |
2002年 | 28篇 |
2001年 | 30篇 |
2000年 | 27篇 |
1999年 | 24篇 |
1998年 | 15篇 |
1997年 | 19篇 |
1996年 | 12篇 |
1995年 | 9篇 |
1994年 | 9篇 |
1993年 | 12篇 |
1992年 | 25篇 |
1991年 | 16篇 |
1990年 | 16篇 |
1989年 | 17篇 |
1988年 | 19篇 |
1987年 | 10篇 |
1986年 | 9篇 |
1985年 | 21篇 |
1984年 | 9篇 |
1983年 | 10篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 5篇 |
1975年 | 9篇 |
1974年 | 7篇 |
1972年 | 5篇 |
1967年 | 5篇 |
排序方式: 共有938条查询结果,搜索用时 15 毫秒
1.
2.
3.
H C Koch W Burmeister N Liappis S Soetadji D Wagner B Langner 《Klinische P?diatrie》1991,203(3):167-172
In 73 healthy (group I) and 32 children and juveniles with insulin dependent diabetes mellitus (IDDM, group II) urinary albumin excretion is determined by radioimmunoassay (RIA). In both groups albumin excretion is observed in every urine sample when measured by RIA (mean +/- SD: group I: 7-19 h: 5.17 +/- 5.28 mg, 19-7 h: 3.86 +/- 4.00 mg, 24 h: 9.03 +/- 8.60 mg; group II: 7-19 h: 6.68 +/- 6.86 mg, 19-7 h: 3.46 +/- 2.82 mg, 24 h: 10.13 +/- 9.25 mg). No significant difference is detected between the values of the two groups. However in diabetic patients a significant difference is observed between diurnal and nocturnal urinary albumin excretion. Microalbuminuria is defined as an albumin excretion above 30 mg/d and is present in 6.9% of the values in group I and in 3.1% in group II. The physiological limits of microalbuminuria in children and juveniles compared to adults and several methods of urine sampling are discussed. 相似文献
4.
K P Cantor A Blair G Everett S VanLier L Burmeister F R Dick R W Gibson L Schuman 《American journal of public health》1988,78(5):570-571
Data from a population-based case-control study of incident leukemia and non-Hodgkin's lymphoma among adult men in Iowa and Minnesota were used to evaluate risk associated with hair dye use. The relative risk for ever using hair dyes was 1.8 (95% confidence interval [CI] = 1.1-2.7) among leukemia patients, and 2.0 (CI = 1.3-3.0) among cases with non-Hodgkin's lymphoma. There was a suggestion of increased risk with extent of hair dye use. Given the widespread use of hair coloring products, these observations deserve more detailed evaluation in populations where the exposure is relatively common. 相似文献
5.
Chiara Riley Jack P. London John A. Burmeister 《Journal of oral pathology & medicine》1992,21(3):124-127
Two hundred HIV-positive subjects were surveyed to determine their periodontal health status. Particular attention was given to the occurrence of a severe and rapidly progressing form of periodontal disease designated "HIV-associated periodontitis", which has been reported as being unique to AIDS patients. Among the subjects comprising the cohort, 85 subjects had good gingival health, 59 subjects exhibited gingivitis, 49 cases of adult periodontitis were observed, 5 subjects presented with advance adult periodontitis, and 2 cases of necrotizing ulcerative periodontitis (NUP) were found within the group. The periodontitis of the patients in this survey did not have unique or pathognomonic characteristics which could set their periodontal disease apart from the periodontal disease seen in HIV negative population. 相似文献
6.
N Lügering R Stoll T Kucharzik G Burmeister C Sorg W Domschke 《Clinical and experimental immunology》1995,101(2):249-253
MRP8 and MRP14 are myeloic related proteins expressed by most circulating and emigrated neutrophils and monocytes. Their composite molecule MRP8/14 (27E10 antigen) was shown to exhibit striking antimicrobial properties. The aim of the present study was to assess the value of MRPs as markers for detection of the different stages of HIV infection (Centres for Disease Control and Prevention, 1993). By employing the ELISA technique we measured serum concentrations of these proteins in samples from 122 HIV patients at the various stages of disease, and the results were compared with those for healthy controls. Serum levels of the heterodimeric molecule 27E10 were significantly increased (P < 0.001) in patients with CDC stages II and III, with the highest levels being in patients with stage III and acute ongoing opportunistic infections. For the single component MRP14, significantly raised levels (P < 0.05) were only found in HIV stage III individuals with acute clinical events. Similar associations were not found for MRP8 alone. Increase was not related to CD4+ cell count. There was a significant correlation between 27E10 antigen serum concentrations and levels of neopterin in patients with HIV stages II and III without acute concurrent illness. Patients being treated with Zidovudine showed no statistically significant variation in levels of 27E10 and its single components MRP8 and MRP14 compared with untreated patients. These findings suggest that elevation of MRP14 levels occurs in HIV+ individuals at later stages post-HIV infection, after the onset of opportunistic infections. 27E10 antigen is concluded to be a potential marker for the different stages of HIV disease. 相似文献
7.
8.
Human skin in organ culture. Elaboration of proteolytic enzymes in the presence and absence of exogenous growth factors. 总被引:1,自引:0,他引:1 下载免费PDF全文
J. Varani P. Perone D. R. Inman W. Burmeister S. B. Schollenberger S. E. Fligiel R. G. Sitrin K. J. Johnson 《The American journal of pathology》1995,146(1):210-217
Proteinase levels were assessed in organ culture fluids from human neonatal foreskin maintained under growth factor-free conditions and in the presence of a combination of growth factors (ie, epidermal growth factor, insulin, hydrocortisone, pituitary extract, and all-trans-retinoic acid). Analysis of culture fluids by gelatin zymography revealed the presence of 92-kd and 72-kd gelatinases. There was a greater amount of 92-kd gelatinase activity in the presence of growth factors whereas the levels of 72-kd gelatinase were similar in growth factor-free and growth factor-containing media. Experiments with keratinocytes and fibroblasts in monolayer culture and with isolated dermal tissue in organ culture indicated that the epithelial component was responsible for most of the 92-kd gelatinase activity whereas fibroblasts were primarily responsible for the 72-kd gelatinase activity. Activation with aminophenyl mercuric acetate, requirement for divalent cations, inhibition with EDTA, and insensitivity to inhibition with phenylmethyl sulfonyl fluoride indicated that both gelatinases were metalloproteinases. In additional studies, culture fluids were examined for the presence of plasminogen activator activity. This was detected in culture fluids from tissues maintained under both conditions but was increased in the growth factor-containing medium. The increased amount seen in the growth factor-containing medium appeared to be due almost entirely to a single factor, ie, all-trans-retinoic acid. In monolayer culture, both keratinocytes and fibroblasts produced plasminogen activator; the level was higher in keratinocyte culture fluids than in culture fluids from fibroblasts. 相似文献
9.
We have investigated the effects of a stronger actomyosin bond on force (Ps) during rapid stretch of active permeabilized rabbit psoas muscle fibers as a function of temperature from 5 to 30 degrees C. The strength of the actomyosin bond is enhanced by addition of polyethylene glycol (PEG), especially in pre-powerstroke states [Chinn et al. (2000) Biophys J 49: 437-451]. We have hypothesized that such states produce much of the force when activated muscles are stretched [Getz et al. (1998) Biophys J 75: 2971-2983]. Addition of PEG to activated fibers produced a small increase in isometric tension, Po (50-90 kN/m2), which was approximately independent of temperature. In contrast PEG produced a dramatic increase in Ps at low temperatures (200-300 kN/m2), but a modest increase at higher temperatures (70-90 kN/m2). We also measured Ps and Po in solutions containing the phosphate analog aluminum fluoride (AlF4) with and without PEG. In the absence of PEG, AlF4 reduced Po much more than Ps. Addition of PEG did not enhance Po, but enhanced Ps significantly. The contrasting effects of PEG on Ps and Po, and the effect of temperature can be explained by a model in which stretch force is produced by pre-powerstroke cross-bridges whose maximum distension is increased by PEG, and isometric force is produced by strongly bound cross-bridges whose bond strength is also enhanced by PEG, but to a lesser extent. 相似文献
10.
Influenza B/Beijing/1/87 neuraminidase heads were isolated from virus via trypsin digestion and characterized by PAGE, N-terminal sequencing, electron microscopy, and enzyme activity. The heads were crystallized into two crystal forms; tetragonal plates, like other neuraminidase crystals described before, that diffract to medium resolution (3 A) and a new form consisting of trigonal prisms or needles that diffract to high resolution (at least 2 A). The gene segment coding for neuraminidase was sequenced and compared with the neuraminidase sequence of B/Lee/40. The deduced amino acid sequences for neuraminidase showed only a 7% difference, whereas those for the NB proteins differed by 20%. 相似文献