全文获取类型
收费全文 | 184246篇 |
免费 | 13901篇 |
国内免费 | 504篇 |
学科分类
医药卫生 | 198651篇 |
出版年
2021年 | 2897篇 |
2020年 | 1681篇 |
2019年 | 2753篇 |
2018年 | 3359篇 |
2017年 | 2457篇 |
2016年 | 2724篇 |
2015年 | 3226篇 |
2014年 | 4491篇 |
2013年 | 7441篇 |
2012年 | 10197篇 |
2011年 | 10641篇 |
2010年 | 6418篇 |
2009年 | 5772篇 |
2008年 | 9908篇 |
2007年 | 10824篇 |
2006年 | 10545篇 |
2005年 | 10580篇 |
2004年 | 10447篇 |
2003年 | 9733篇 |
2002年 | 9780篇 |
2001年 | 3449篇 |
2000年 | 3235篇 |
1999年 | 3208篇 |
1998年 | 2418篇 |
1997年 | 2090篇 |
1996年 | 1816篇 |
1995年 | 1875篇 |
1994年 | 1610篇 |
1993年 | 1545篇 |
1992年 | 2393篇 |
1991年 | 2352篇 |
1990年 | 2187篇 |
1989年 | 2117篇 |
1988年 | 1915篇 |
1987年 | 1883篇 |
1986年 | 1815篇 |
1985年 | 1788篇 |
1984年 | 1683篇 |
1983年 | 1621篇 |
1982年 | 1591篇 |
1981年 | 1536篇 |
1980年 | 1415篇 |
1979年 | 1326篇 |
1978年 | 1105篇 |
1977年 | 1121篇 |
1976年 | 952篇 |
1975年 | 961篇 |
1974年 | 956篇 |
1973年 | 837篇 |
1972年 | 762篇 |
排序方式: 共有10000条查询结果,搜索用时 27 毫秒
991.
Fanasy P. Deming Ibtisam Al-Hashimi Nasser Haghighat William W. Hallmon David G. Kerns Celeste Abraham Francisco Rivera-Hidalgo 《Journal of oral pathology & medicine》2007,36(3):132-135
Background: Reduction in salivary secretion is the hallmark of Sjögren's syndrome (SS). Calmodulin (CaM) and calmodulin binding proteins (CaMBPs) play a key role in the secretory process of saliva. Recent studies have suggested that SS‐B, an autoantibody associated with SS, is a CaMBP. This finding suggests that CaMBP may contribute to the loss of saliva in SS. To better understand the role(s) of these proteins in SS, the purpose of this study was to compare salivary CaMBPs in Sjögren's patients and controls. Methods: Saliva samples were collected from 20 patients and 20 age‐, race‐, and gender‐matched controls. CaM overlay was used to identify CaMBPs in saliva of patients and controls. Results: Higher number of salivary CaMBPs was observed among patients than controls. Conclusions: The increased number of salivary CaMBPs in SS may suggest a potential role for these proteins in the pathogenesis of the disease. 相似文献
992.
Selective laser trabeculoplasty in phakic and pseudophakic eyes. 总被引:2,自引:0,他引:2
BACKGROUND AND OBJECTIVE: To evaluate the effect of pseudophakia on the success of selective laser trabeculoplasty in lowering intraocular pressure (IOP). PATIENTS AND METHODS: In this retrospective, nonrandomized clinical trial, a chart review of all patients who underwent selective laser trabeculoplasty from September 2002 to June 2004 using a frequency-doubled Q-switched 532-nm Nd:YAG laser was performed. Changes in IOP and statistical significance were determined at each follow-up period. Average decrease in IOP and success rates for phakic and pseudophakic eyes were compared statistically at each time period. RESULTS: In the phakic group, mean IOP decreased from 18.1 to 15.5 mm Hg (P < .0005) and mean glaucoma medication use decreased from 2.1 to 1.6 medications after 24 months of follow-up. In the pseudophakic group, mean IOP decreased from 18.3 to 15.2 mm Hg (P < .005) and mean glaucoma medication use decreased from 2.2 to 1.6 medications. Success rates ranged from 54% to 67% in the phakic group and 52% to 65% in the pseudophakic group. No statistically significant difference between phakic and pseudophakic eyes in decreased IOP or success rates was seen at any time point (P > .05). No significant complications occurred in either group. CONCLUSIONS: Selective laser trabeculoplasty is effective in lowering IOP in both phakic and pseudophakic patients. 相似文献
993.
When skin fibroblasts are grown in culture on collagen gels, the collagen gels contract. We have studied the effects of various steroids on the contraction process. Cortisol, beta-estradiol and dexamethasone inhibited fibroblast-mediated gel contraction at low (10(-8) to 10(-9) M) concentrations whereas dihydrotestosterone was without effect. These effects were time and concentration dependent and could be reversed if the steroids were removed. This system may be useful for assaying the activities of various steroids in terms of their activities and modulating effects on connective tissue. 相似文献
994.
995.
William H. Cormier Akira Otani L. Sherilyn Cormier 《Cognitive therapy and research》1986,10(1):95-108
The present study assessed the effects of problem-solving (D'Zurilla & Goldfried, 1971) training on two problem-solving tasks. Sixty-one subjects were assigned randomly to and trained in one of the following groups: general orientation (GO)-problem definition (PD)-generation of alternatives (GA)-decision making (DM), GO-PD-GA, GO-PD-DM, GO-GA-DM, GO, and a control group. The six groups did not differ significantly at pretesting on the measures of selecting the best alternative solution and describing problem-solving behaviors used to solve problems. Training was significantly effective on selecting the best alternative solution for all groups compared with the control group at the time of posttesting. The GO-PD-GA-DM and GO-PD-DM groups described significantly more problem-solving behaviors than the GO-PD-GA, GO-GA-DM, and GO groups. All five treatment groups performed significantly better than the control group at the time of post-testing. At follow-up 1 month after posttesting, groups trained with the PD component selected significantly better alternatives than the groups without PD training. Groups trained with the DM component described significantly more problem-solving behaviors at follow-up than the groups trained without the DM component. 相似文献
996.
997.
Lysia S. Forno J. William Langston Louis E. DeLanney Ian Irwin George A. Ricaurte 《Annals of neurology》1986,20(4):449-455
Systemic administration of the recently discovered neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) produces severe clinical parkinsonism and degeneration of the substantia nigra in humans and monkeys. In previous studies, no convincing structural damage to nerve cells outside the substantia nigra could be demonstrated in subhuman primates. Using a protracted MPTP regimen and older animals, we now report locus ceruleus lesions and eosinophilic inclusion bodies in squirrel monkeys. The inclusions were seen only in areas where Lewy bodies are found in human Parkinson's disease. No such abnormalities were seen in control animals. These findings suggest that similarities between the neuropathology of MPTP-induced parkinsonism in the monkey and human Parkinson's disease are greater than first thought and increase the usefulness of the MPTP monkey model for research in Parkinson's disease. 相似文献
998.
In 44 endogenously depressed patients, response to total sleep deprivation (TSD) was investigated as a function of several biographical and clinical variables. All patients were subjected to a schedule of sleep-TSD-sleep-TSD. Antidepressant drug treatment (clomipramine) was started on the day before the first TSD. Sex, age, educational status, number of previous hospitalizations and duration of the current depressive episode were not related to the response to either the first or the second TSD. Likewise, no significant differences were found in the responses of unipolar and bipolar patients. In contrast, diurnal variation appeared to be positively correlated with response to TSD. Depressives with psychotic features reacted more favourably than non-psychotic depressives. 相似文献
999.
Binding of a specific dopamine D1 receptor antagonist,125I-SCH 23982, was measured in rat brain sections by quantitative autoradiography at various time intervals, following a knife cut through the striatonigral pathway. Twenty-four hours after lesioning, accumulations of D1 receptor binding sites were found in sagittal sections both rostral and caudal to the lesion site. No other regions studied (caudate-putamen, nucleus accumbens, olfactory tubercle, and substantia nigra pars reticulata) showed any change in D1 receptor binding 24h after the lesion. In brain sections obtained 10 days after lesioning, only the substantia nigra pars reticulata had a significant decrease in D1 receptors ipsilateral to the lesion. These findings suggest the possibility of a presence of bidirectional axonal transport of D1 receptors in rat striatonigral pathway. 相似文献
1000.