全文获取类型
收费全文 | 1152篇 |
免费 | 75篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 46篇 |
妇产科学 | 20篇 |
基础医学 | 122篇 |
口腔科学 | 17篇 |
临床医学 | 106篇 |
内科学 | 485篇 |
皮肤病学 | 31篇 |
神经病学 | 52篇 |
特种医学 | 91篇 |
外科学 | 71篇 |
综合类 | 28篇 |
预防医学 | 27篇 |
眼科学 | 7篇 |
药学 | 73篇 |
中国医学 | 1篇 |
肿瘤学 | 41篇 |
出版年
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 19篇 |
2018年 | 9篇 |
2017年 | 10篇 |
2016年 | 14篇 |
2015年 | 17篇 |
2014年 | 30篇 |
2013年 | 56篇 |
2012年 | 39篇 |
2011年 | 40篇 |
2010年 | 39篇 |
2009年 | 37篇 |
2008年 | 48篇 |
2007年 | 53篇 |
2006年 | 61篇 |
2005年 | 51篇 |
2004年 | 38篇 |
2003年 | 43篇 |
2002年 | 37篇 |
2001年 | 30篇 |
2000年 | 25篇 |
1999年 | 21篇 |
1998年 | 25篇 |
1997年 | 46篇 |
1996年 | 38篇 |
1995年 | 28篇 |
1994年 | 30篇 |
1993年 | 30篇 |
1992年 | 20篇 |
1991年 | 12篇 |
1990年 | 25篇 |
1989年 | 41篇 |
1988年 | 24篇 |
1987年 | 29篇 |
1986年 | 25篇 |
1985年 | 23篇 |
1984年 | 14篇 |
1983年 | 8篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1978年 | 6篇 |
1977年 | 11篇 |
1976年 | 5篇 |
1975年 | 8篇 |
1974年 | 5篇 |
1968年 | 5篇 |
1967年 | 5篇 |
1966年 | 3篇 |
排序方式: 共有1230条查询结果,搜索用时 31 毫秒
11.
12.
13.
Synergy between the genes for butyrylcholinesterase K variant and apolipoprotein E4 in late-onset confirmed Alzheimer's disease 总被引:5,自引:2,他引:5
The allelic frequency of the gene for the K variant of
butyrylcholinesterase (BCHE-K) was 0.17 in 74 subjects with late-onset (age
> 65 years) histopathologically diagnosed Alzheimer's disease (AD),
which was higher than the frequencies in 104 elderly control subjects
(0.09), in 14 early-onset cases of confirmed AD (0.07) and in 29 confirmed
cases of other dementia (0.10). The association of BCHE-K with late-onset
AD was limited to carriers of the epsilon 4 allele of the apolipoprotein E
gene (APOE), among whom the presence of BCHE-K gave an odds ratio of
confirmed late-onset AD of 6.9 (95% C.I. 1.65-29) in subjects > 65 years
and of 12.8 (1.9-86) in subjects > 75 years. In APOE epsilon 4 carriers
over 75 years, only 1/22 controls, compared with 10/24 confirmed late-onset
AD cases, had BCHE-K. We suggest that BCHE-K, or a nearby gene on
chromosome 3, acts in synergy with APOE epsilon 4 as a susceptibility gene
for late-onset AD.
相似文献
14.
15.
DL?MagerEmail author AD?Haffajee PM?Devlin CM?Norris MR?Posner JM?Goodson 《Journal of translational medicine》2005,3(1):27
Background
The purpose of the present investigation was to determine if the salivary counts of 40 common oral bacteria in subjects with an oral squamous cell carcinoma (OSCC) lesion would differ from those found in cancer-free (OSCC-free) controls. 相似文献16.
17.
Keld Kjeldsen Aage Nørgaard Torben Clausen 《Pflügers Archiv : European journal of physiology》1985,404(4):365-373
The relationship between the number of3H-ouabain binding sites and the Na, K-pump mediated K-uptake has been characterized in rat soleus muscle. By brief exposure to3H-ouabain (1×10–6–1×10–5mol/l) in vitro, it could be measured that 19–94% of the ouabain binding sites had been occupied. This was associated with a proportionate decrease in the ouabain suppressible K-uptake indicating that under strictly standardized conditions, measurements of3H-ouabain binding sites quantify functional Na,K-pumps.When 3 week old rats were K-depleted for a further week followed by K-repletion 2 h before measurements, the3H-ouabain binding site concentration was 61% lower than in age-matched control soleus muscles. However, the ouabain suppressible K-uptake was only reduced by 35% partly because intracellular Na remained higher in the muscles obtained from K-depleted rats.From the 1st to the 4th week of life, the3H-ouabain binding site concentration increased 2.9-fold. In contrast, the ouabain suppressible K-uptake decreased by a factor 3.5. Accordingly, in muscles from 1 week old rats, the ouabain suppressible K-uptake per3H-ouabain binding site was 10-fold higher than in muscles from 4 week old rats. This difference could not be accounted for by changes in intracellular Na, total or extracellular water. It may be related to differentiation and change in structure.On the basis of the present results and those reported in the literature for mouse and frog skeletal muscle it was calculated that under resting conditions at 30°C in vitro, isolated skeletal muscles only utilize between 3 and 25% of their total capacity for active Na, K-transport. Therefore, variations in the total Na, K-pump capacity may not readily be detected in measurements of the ouabain suppressible rate of K-uptake. 相似文献
18.
The effect of a cold pressor test (CPT) on haemodynamics in relation to general and regional sympathetic activity and arginin vasopressin (AVP), was studied in eleven patients with severe congestive heart failure (CHF). Compared to an age-matched control group (C), resting arterial plasma noradrenaline (NA) (419 +/- 77 vs. 182 +/- 15 pg ml-1), and adrenaline (A) (142 +/- 28 vs 54 +/- 10 pg ml-1) were higher (P less than 0.05) in CHF. AVP showed no significant difference (14 +/- 4 vs. 9 +/- 4 pg ml-1). During CPT systolic and diastolic blood pressure and systemic vascular resistance increased (P less than 0.01), as did NA (delta 114 +/- 39 pg ml-1, P less than 0.01), A (delta 33 +/- 10 pg ml-1, P less than 0.01) and heart rate (delta 10 beats min-1, P less than 0.01). The myocardial v-a difference of NA decreased (P less than 0.05), but was unchanged across the renal vascular bed during CPT. The a-v difference of NA in the hepatic vascular bed, and fractional extraction of A in the coronary sinus, renal and hepatic vascular beds remained unchanged during CPT. AVP did not change significantly and no change in cardiac index or left ventricular filling pressure was observed during CPT. These data suggest that despite an increased activation of the sympathetic nervous system at rest, a further increase in blood pressure and catecholamines took place during CPT. Thus, the effect of a CPT which activates the central sympathetic system seems not to be altered in patients with severe CHF. 相似文献
19.
Ionizing radiation is a carcinogen that induces oxidative DNA damage. 8-
Hydroxy-2'-deoxyguanosine (8-OHdG) is a relatively abundant, mutagenic
lesion that is widely regarded as a reliable index of oxidative DNA damage.
The purpose of this study was to examine the effects of X- radiation on
levels of 8-OHdG in the context of an experimental model for breast cancer
in which chronic radiation exposure has been shown to be carcinogenic in
Sprague-Dawley rats. A secondary objective of this study was to determine
if the use of phenol during DNA isolation affected the concentration of
8-OHdG subsequently measured. Our results indicate that a profoundly
carcinogenic dose of radiation induced a small but significant increase in
8-OHdG concentration in mammary gland DNA, and that the use of a
phenol-based versus a salt-based method of DNA isolation had no significant
impact on the levels of 8-OHdG detected in either control or irradiated
tissue.
相似文献
20.