全文获取类型
收费全文 | 3613篇 |
免费 | 457篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 141篇 |
儿科学 | 108篇 |
妇产科学 | 46篇 |
基础医学 | 601篇 |
口腔科学 | 59篇 |
临床医学 | 374篇 |
内科学 | 826篇 |
皮肤病学 | 41篇 |
神经病学 | 249篇 |
特种医学 | 46篇 |
外科学 | 602篇 |
综合类 | 49篇 |
一般理论 | 7篇 |
预防医学 | 330篇 |
眼科学 | 132篇 |
药学 | 218篇 |
中国医学 | 1篇 |
肿瘤学 | 253篇 |
出版年
2023年 | 36篇 |
2022年 | 46篇 |
2021年 | 92篇 |
2020年 | 56篇 |
2019年 | 66篇 |
2018年 | 84篇 |
2017年 | 57篇 |
2016年 | 64篇 |
2015年 | 50篇 |
2014年 | 83篇 |
2013年 | 112篇 |
2012年 | 171篇 |
2011年 | 181篇 |
2010年 | 89篇 |
2009年 | 89篇 |
2008年 | 159篇 |
2007年 | 176篇 |
2006年 | 157篇 |
2005年 | 149篇 |
2004年 | 169篇 |
2003年 | 144篇 |
2002年 | 139篇 |
2001年 | 89篇 |
2000年 | 99篇 |
1999年 | 81篇 |
1998年 | 31篇 |
1997年 | 31篇 |
1996年 | 41篇 |
1994年 | 34篇 |
1993年 | 39篇 |
1992年 | 49篇 |
1991年 | 46篇 |
1990年 | 56篇 |
1989年 | 49篇 |
1988年 | 39篇 |
1987年 | 62篇 |
1986年 | 47篇 |
1985年 | 47篇 |
1984年 | 44篇 |
1983年 | 41篇 |
1982年 | 40篇 |
1981年 | 51篇 |
1980年 | 34篇 |
1979年 | 65篇 |
1978年 | 37篇 |
1977年 | 63篇 |
1976年 | 41篇 |
1975年 | 51篇 |
1974年 | 46篇 |
1973年 | 39篇 |
排序方式: 共有4083条查询结果,搜索用时 0 毫秒
1.
2.
A number of vitamin D3 metabolites inhibit benzodiazepine- and dimethyl sulfoxide-induced differentiation of Friend erythroleukemia cells. The inhibition is dose dependent and occurs at nM concentrations. The order of potency of these compounds is 1,25-dihydroxycholecalciferol greater than 1,25,26-trihydroxycholecalciferol greater than 1,24R,25-trihydroxycholecalciferol greater than 1 alpha-hydroxycholecalciferol greater than 24R,25-dihydroxycholecalciferol greater than 25S,26-dihydroxycholecalciferol. The inhibition is maximal when the vitamin D3 analogs are added together with the inducer, and becomes progressively decreased with delayed addition. These results suggest that the vitamin D3 metabolites may play a regulatory role in erythropoiesis. 相似文献
3.
Dawn Hastreiter MD PhD ; Jeannie Chao BS ; QI Wang MD ; Richard M. Ozuna MD ; Myron Spector PhD 《Wound repair and regeneration》2004,12(4):430-438
That a contractile actin isoform has been found in cells of other cartilage tissues in healing and disease states prompted this investigation of the presence of alpha-smooth muscle actin (alpha-SMA) in pathological human intervertebral disc tissue. The presence of this isoform has been reported in human intervertebral disc specimens obtained at autopsy from subjects for whom there were no reported symptoms. An objective of this study was to evaluate the cell density and percentage of alpha-SMA-containing cells in pathological nucleus pulposus tissue obtained from lumbar disc surgery from 17 patients. Additionally, explants of nucleus pulposus material were cultured to determine how alpha-SMA expression changed with time in vitro. Seventy-six 5-mm diameter explants (approximately 2 mm thick) pooled from six lumbar surgeries were cultured for 1, 2, 4, or 6 weeks. Microtomed sections of paraffin-embedded specimens were stained with hematoxylin and eosin or a monoclonal antibody to alpha-SMA. Histologically, cells were categorized as to alpha-SMA phenotype (positive or negative), and the areal cell density was determined. The evaluation of the cultured nucleus pulposus explants also included documentation of the percentage of cells that were round or elongated and the percentage of the cells that were part of a group (group: >/= 2 cells). Every nucleus pulposus section exhibited the presence of alpha-SMA-containing cells, which accounted for approximately 24 percent of the cells in vivo. In vivo, the cell density was significantly higher in older individuals (p = 0.02). The average time for cell outgrowth from the explants was 8.6 days. Approximately 10-15 percent of the cells in the explants stained positive for alpha-SMA. The time in culture had no significant effect on any of the outcome measures except the percentage of alpha-SMA-containing cells that were round (p = 0.008), with values decreasing through 4 weeks and then slightly rising at 6 weeks. The role of alpha-SMA in intervertebral disc pathology warrants further investigation. 相似文献
4.
5.
6.
Sir, Scarpioni described a patient with acute hydrothorax complicatingCAPD who was treated with repeated autologous blood instillationinto the pleural cavity together with a switch in the mode ofdialysis 相似文献
7.
8.
9.
The external subdivision of the lateral parabrachial nucleus (LPBE) shows strong Fos-like immunoreactivity (FLI) following anorectic doses of the indirect serotonin agonist dexfenfluramine (DFEN). In an effort to determine the contribution of the LPBE to DFEN-induced anorexia, bilateral ibotenate lesions were made in the LPBE, and the effects of the lesion on DFEN-induced anorexia and FLI as well as c-June-like immunoreactivity (JLI) were examined. It was found that LPBE lesion significantly attenuated DFEN anorexia: in a 1-h food intake test following 24-h food deprivation, DFEN (2 mg/kg) suppressed food intake by 60% in intact rats but only 34% in rats with LPBE lesions. In addition to this behavioral change, LPBE lesion completely abolished DFEN-induced FLI and JLI in the lateral subdivision of the central nucleus of the amygdala (CeL) and laterodorsal subdivision of the bed nucleus of stria terminalis (BSTLD), both of which showed strong FLI and JLI in intact rats. DFEN-induced FLI and JLI in other brain regions were not affected by LPBE lesion, including the ventromedial and lateral hypothalamus, caudate-putamen, and the nucleus of the solitary tract (NST). The parallel loss of DFEN-induced anorexia and FLI/JLI following LPBE lesion raises the novel possibility that LPBE-CeL/BSTLD pathway may be involved in DFEN anorexia. 相似文献
10.
The Multiphasic Environmental Assessment Procedure (MEAP; Moos and Lemke, 1984) was used to assess three long-stay settings within a geriatric hospital, one of which is a non-nursing unit committed to the philosophy of residents viewing the setting as their own home. Findings suggest positive outcomes for residents on the nonnursing unit, and support the view that types of care fostering independence and personal responsibility of elderly residents in their setting may be associated with increased mental functioning and activity. The lack of trained nursing staff had no detrimental effect on any measure of resident life, and some specific caring practices on the unit may be interpreted as having a positive outcome for residents. 相似文献