全文获取类型
收费全文 | 951篇 |
免费 | 67篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 18篇 |
妇产科学 | 50篇 |
基础医学 | 112篇 |
口腔科学 | 24篇 |
临床医学 | 125篇 |
内科学 | 283篇 |
皮肤病学 | 9篇 |
神经病学 | 75篇 |
特种医学 | 52篇 |
外科学 | 122篇 |
综合类 | 3篇 |
一般理论 | 1篇 |
预防医学 | 43篇 |
眼科学 | 6篇 |
药学 | 46篇 |
中国医学 | 2篇 |
肿瘤学 | 48篇 |
出版年
2023年 | 3篇 |
2022年 | 9篇 |
2021年 | 25篇 |
2020年 | 7篇 |
2019年 | 21篇 |
2018年 | 22篇 |
2017年 | 21篇 |
2016年 | 21篇 |
2015年 | 21篇 |
2014年 | 35篇 |
2013年 | 50篇 |
2012年 | 57篇 |
2011年 | 69篇 |
2010年 | 48篇 |
2009年 | 50篇 |
2008年 | 75篇 |
2007年 | 84篇 |
2006年 | 83篇 |
2005年 | 93篇 |
2004年 | 55篇 |
2003年 | 52篇 |
2002年 | 52篇 |
2001年 | 13篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1994年 | 8篇 |
1993年 | 1篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1965年 | 3篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1962年 | 3篇 |
1961年 | 2篇 |
1960年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有1028条查询结果,搜索用时 15 毫秒
1.
Lactobacillus johnsonii La1 attenuates Helicobacter pylori-associated gastritis and reduces levels of proinflammatory chemokines in C57BL/6 mice 总被引:3,自引:0,他引:3
Sgouras DN Panayotopoulou EG Martinez-Gonzalez B Petraki K Michopoulos S Mentis A 《Clinical and diagnostic laboratory immunology》2005,12(12):1378-1386
In clinical settings, Lactobacillus johnsonii La1 administration has been reported to have a favorable effect on Helicobacter pylori-associated gastritis, although the mechanism remains unclear. We administered, continuously through the water supply, live La1 to H. pylori-infected C57BL/6 mice and followed colonization, the development of H. pylori-associated gastritis in the lamina propria, and the levels of proinflammatory chemokines macrophage inflammatory protein 2 (MIP-2) and keratinocyte-derived cytokine (KC) in the serum and gastric tissue over a period of 3 months. We documented a significant attenuation in both lymphocytic (P=0.038) and neutrophilic (P=0.003) inflammatory infiltration in the lamina propria as well as in the circulating levels of anti-H. pylori immunoglobulin G antibodies (P=0.003), although we did not observe a suppressive effect of La1 on H. pylori colonizing numbers. Other lactobacilli, such as L. amylovorus DCE 471 and L. acidophilus IBB 801, did not attenuate H. pylori-associated gastritis to the same extent. MIP-2 serum levels were distinctly reduced during the early stages of H. pylori infection in the La1-treated animals, as were gastric mucosal levels of MIP-2 and KC. Finally, we also observed a significant reduction (P=0.046) in H. pylori-induced interleukin-8 secretion by human adenocarcinoma AGS cells in vitro in the presence of neutralized (pH 6.8) La1 spent culture supernatants, without concomitant loss of H. pylori viability. These observations suggest that during the early infection stages, administration of La1 can attenuate H. pylori-induced gastritis in vivo, possibly by reducing proinflammatory chemotactic signals responsible for the recruitment of lymphocytes and neutrophils in the lamina propria. 相似文献
2.
3.
Hans-Heiner Kramer Michael Sommer Spyros Rammos Otto Krogmann 《European journal of pediatrics》1995,154(9):700-707
This study reports our experience with low-dose prostaglandin E1 (PGE1) treatment of 91 newborns with ductus dependent congenital heart disease (CHD). PGE1 efficacy, side-effects as well as the cardiovascular and respiratory profile of the patients were analysed. PGE1 doses > 0.02 g/kg per minute were used for only 5.3% of the total 23 656 h of treatment. The mean systolic blood pressures did not differ from the normal mean for patients with cyanotic CHD, while the diastolic values were lowered. Respiratory support was required only during 13.7% of the total treatment time. Apnoeas occurred in 21 (38%) of the 55 spontaneously breathing infants, who all had a cyanotic CHD. The incidence of apnoeas was lower during treatment with doses < 0.01 g/kg per minute. 相似文献
4.
Keiko Yamanaka Nikolaos V. Sofikitis Ikuo Miyagawa Yasuhisa Yamamoto Toshiko Toda Spyros Antypas Dimitrios Dimitriadis Manami Takenaka Koji Taniguchi Katsuhiko Takahashi Sanae Tsukamoto Hiroshi Kawamura Martin Neil 《Journal of assisted reproduction and genetics》1997,14(1):55-62
Purpose: Our objective was to apply ooplasmic round spermatid nuclear injections for the treatment of nonobstructive azoospermia.
Materials: Participants were nine azoospermic men who had previously undergone diagnostic testicular biopsy. Spermatogenetic arrest
was diagnosed at the round spermatid stage (n=6) or primary spermatocyte stage (n=3). A second (therapeutic) testicular biopsy
was performed and round spermatid nuclei were recovered from all the participants.
Results: Forty-nine mature oocytes were successfully injected with nuclei and then cultured for 72 hr. Twenty-four embryos were transferred
to nine women. No pregnancy was achieved.
Conclusions: Round spermatids can be recovered from therapeutic testicular biopsy material of men negative for round spermatids in previous
routine diagnostic testicular biopsy specimens. Round spermatid nuclear injections may play a role in the treatment of nonobstructive
azoospermia. 相似文献
5.
Anyfanti Panagiota Gavriilaki Eleni Pyrpasopoulou Athina Triantafyllou George Triantafyllou Areti Chatzimichailidou Sofia Gkaliagkousi Eugenia Aslanidis Spyros Douma Stella 《Clinical rheumatology》2016,35(5):1411-1411
Clinical Rheumatology - 相似文献
6.
Aggeliki Poulou Evgenia Grivakou Georgia Vrioni Vassiliki Koumaki Theodoros Pittaras Spyros Pournaras Athanassios Tsakris 《Journal of clinical microbiology》2014,52(5):1483-1489
The worldwide dissemination of Enterobacteriaceae producing AmpC β-lactamases and carbapenemases makes difficult the phenotypic detection of extended-spectrum β-lactamases (ESBLs), as they may be masked by these additional enzymes. A modification of the CLSI ESBL confirmatory test was developed and evaluated in a comparative study for its ability to successfully detect ESBLs among Enterobacteriaceae producing various carbapenemases (Klebsiella pneumoniae carbapenemase [KPC], VIM, NDM, and OXA-48) and plasmidic or derepressed AmpCs. The modified CLSI ESBL confirmatory test was performed with cefotaxime and ceftazidime disks with and without clavulanate, on which both boronic acid (BA) and EDTA were dispensed. A total of 162 genotypically confirmed ESBL-positive Enterobacteriaceae isolates (83 carbapenemase/ESBL producers, 25 AmpC/ESBL producers, and 54 ESBL-only producers) were examined. For comparison, 139 genotypically confirmed ESBL-negative Enterobacteriaceae isolates (94 of them possessed carbapenemases and 20 possessed AmpCs) were also tested. The standard CLSI ESBL confirmatory test was positive for 106 of the 162 ESBL producers (sensitivity, 65.4%) and showed false-positive results for 4 of the 139 non-ESBL producers (specificity, 97.1%). The modified CLSI ESBL confirmatory test detected 158 of 162 ESBL producers (sensitivity, 97.5%) and showed no false-positive results for non-ESBL producers (specificity, 100%). The findings of the study demonstrate that the modified CLSI ESBL confirmatory test using antibiotic disks containing both BA and EDTA accurately detects ESBLs in Enterobacteriaceae regardless of the coexistence of additional β-lactam resistance mechanisms. 相似文献
7.
8.
9.
10.
Nina G. G. Domingo Srinidhi Balasubramanian Sumil K. Thakrar Michael A. Clark Peter J. Adams Julian D. Marshall Nicholas Z. Muller Spyros N. Pandis Stephen Polasky Allen L. Robinson Christopher W. Tessum David Tilman Peter Tschofen Jason D. Hill 《Proceedings of the National Academy of Sciences of the United States of America》2021,118(20)
Agriculture is a major contributor to air pollution, the largest environmental risk factor for mortality in the United States and worldwide. It is largely unknown, however, how individual foods or entire diets affect human health via poor air quality. We show how food production negatively impacts human health by increasing atmospheric fine particulate matter (PM2.5), and we identify ways to reduce these negative impacts of agriculture. We quantify the air quality–related health damages attributable to 95 agricultural commodities and 67 final food products, which encompass >99% of agricultural production in the United States. Agricultural production in the United States results in 17,900 annual air quality–related deaths, 15,900 of which are from food production. Of those, 80% are attributable to animal-based foods, both directly from animal production and indirectly from growing animal feed. On-farm interventions can reduce PM2.5-related mortality by 50%, including improved livestock waste management and fertilizer application practices that reduce emissions of ammonia, a secondary PM2.5 precursor, and improved crop and animal production practices that reduce primary PM2.5 emissions from tillage, field burning, livestock dust, and machinery. Dietary shifts toward more plant-based foods that maintain protein intake and other nutritional needs could reduce agricultural air quality–related mortality by 68 to 83%. In sum, improved livestock and fertilization practices, and dietary shifts could greatly decrease the health impacts of agriculture caused by its contribution to reduced air quality.The health and environmental consequences of feeding the increasingly large and affluent global population are becoming increasingly apparent. These consequences have spurred interest in identifying food production practices and diets that improve human health and reduce environmental harm. Recent work has demonstrated that many of the opportunities for food producers and consumers to improve nutritional outcomes also have environmental benefits, such as reducing greenhouse gas emissions, land and water use, and eutrophication (1–6). It is largely unknown, however, how individual foods and diets affect air quality, even though air pollution is the largest environmental mortality risk factor in the United States and globally (7, 8), and agriculture is itself known to be a major contributor to reduced air quality (8, 9). In the United States alone, atmospheric fine particulate matter (PM2.5) from anthropogenic sources is responsible for about 100,000 premature deaths each year, one-fifth of which are linked to agriculture (10, 11).Here, we show how different foods affect human health by reducing air quality. We consider the emission of pollutants that contribute to atmospheric PM2.5, the chronic exposure to which increases the incidence of premature mortality from cardiovascular disease, cancer, and stroke (12, 13). These pollutants include directly emitted PM2.5 (primary PM2.5) and PM2.5 formed in the atmosphere (secondary PM2.5) from the precursors ammonia (NH3), nitrogen oxides (NOx), sulfur dioxide (SO2), and nonmethane volatile organic compounds (NMVOCs). From a spatially explicit inventory of emissions of primary PM2.5 and secondary PM2.5 precursors from agricultural supply chain activities for commodities in the contiguous United States (SI Appendix, Figs. S1 and S2) (14, 15) (Materials and Methods), we estimate increases in atmospheric concentrations of total (primary + secondary) PM2.5 attributable to agricultural emissions; total PM2.5 transport, chemistry, and removal; and exposure of populations to total PM2.5 using an ensemble of three independent air quality models (16–19). We describe damages attributable to 95 agricultural commodities and 67 final food products (full list in SI Appendix, Table S1), which cover >99% of US agricultural production (20). 相似文献