全文获取类型
收费全文 | 4690篇 |
免费 | 348篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 144篇 |
妇产科学 | 62篇 |
基础医学 | 757篇 |
口腔科学 | 195篇 |
临床医学 | 452篇 |
内科学 | 948篇 |
皮肤病学 | 47篇 |
神经病学 | 465篇 |
特种医学 | 251篇 |
外科学 | 737篇 |
综合类 | 38篇 |
一般理论 | 1篇 |
预防医学 | 217篇 |
眼科学 | 49篇 |
药学 | 267篇 |
中国医学 | 6篇 |
肿瘤学 | 382篇 |
出版年
2022年 | 34篇 |
2021年 | 83篇 |
2020年 | 42篇 |
2019年 | 62篇 |
2018年 | 115篇 |
2017年 | 75篇 |
2016年 | 104篇 |
2015年 | 128篇 |
2014年 | 128篇 |
2013年 | 183篇 |
2012年 | 241篇 |
2011年 | 283篇 |
2010年 | 141篇 |
2009年 | 173篇 |
2008年 | 246篇 |
2007年 | 308篇 |
2006年 | 268篇 |
2005年 | 322篇 |
2004年 | 344篇 |
2003年 | 284篇 |
2002年 | 256篇 |
2001年 | 102篇 |
2000年 | 71篇 |
1999年 | 78篇 |
1998年 | 60篇 |
1997年 | 71篇 |
1996年 | 45篇 |
1995年 | 45篇 |
1994年 | 47篇 |
1993年 | 37篇 |
1992年 | 42篇 |
1991年 | 45篇 |
1990年 | 46篇 |
1989年 | 47篇 |
1988年 | 41篇 |
1987年 | 41篇 |
1986年 | 30篇 |
1985年 | 31篇 |
1984年 | 20篇 |
1983年 | 27篇 |
1982年 | 25篇 |
1981年 | 22篇 |
1980年 | 15篇 |
1979年 | 22篇 |
1978年 | 17篇 |
1977年 | 24篇 |
1976年 | 15篇 |
1975年 | 20篇 |
1974年 | 18篇 |
1973年 | 15篇 |
排序方式: 共有5053条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
Christiana Winkler Barbara Frick Katharina Schroecksnadel Harald Schennach Dietmar Fuchs 《Food and chemical toxicology》2006,44(12):2003-2007
Antioxidant preservatives prolong the quality of food and ensure the nutritional adequacy, palatability and safety of many processed foods and beverages. Effects of sodium sulfite (E221) and sorbic acid (E200) were investigated in human peripheral blood mononuclear cells (PBMC) which were purified from blood of healthy donors. Cells were stimulated with the mitogen phytohaemagglutinin in vitro, which induces proliferation of T-cells and the production of Th1-type cytokines like interferon-γ. The latter triggers enzyme indoleamine (2,3)-dioxygenase, which degrades tryptophan, and GTP cyclohydrolase I, which leads to increased neopterin production, in monocyte-derived macrophages. Sodium sulfite and sorbic acid suppressed both these biochemical changes in a dose-dependent way (P < 0.01 at 1 mM sodium sulfite and 50 mM sorbic acid). Data demonstrate a suppressive influence of sodium sulfite and sorbic acid on the activated Th1-type immune response. 相似文献
5.
Paul Wexberg MD BM Richard Pacher MD Suzanne Rdler MD Katharina Kiss MD Gilbert Beran MD Michael Grimm MD Gerald Maurer MD Dietmar Glogar MD FESC 《The Journal of heart and lung transplantation》2002,21(12):583-1263
BACKGROUND: Endothelin, a peptide with strong vasoconstrictive and mitogenic properties, has been found to increase after cardiac transplantation. We therefore assessed the association between its precursor peptide, big endothelin-1, and intimal hyperplasia and coronary flow reserve after heart transplantation. METHODS: Thirty-five patients without hemodynamically significant coronary artery disease after heart transplantation were investigated: Average peak flow velocity in the left anterior descending artery (LAD) was assessed by intracoronary Doppler at baseline as well as after injection of adenosine; coronary flow reserve was calculated as a ratio of both and was corrected for patient age and baseline average peak flow velocity. Lumen, intima + media and total vessel area were measured by intracoronary ultrasound. The plasma concentration of big endothelin-1 in venous blood was determined by radioimmunoassay. RESULTS: Patients with elevated big endothelin-1 levels (>2 fmol/ml) tended to have a decreased corrected coronary flow reserve (2.60 +/- 0.9 vs 3.21 +/- 1.0, p = 0.078). They also had a significantly larger intima + media area (5.82 +/- 2.9 vs 2.37 +/- 2.9 mm(2), p = 0.004) and total vessel area (18.36 +/- 5.8 vs 12.81 +/- 4.8 mm(2), p = 0.012) than those with normal plasma concentrations. CONCLUSIONS: Our study suggests an association between elevated big endothelin-1 plasma levels and the development of intimal hyperplasia and reduction of coronary flow reserve after cardiac transplantation. 相似文献
6.
Andrew E. Springer Kayan Lewis Steven H. Kelder Maria E. Fernandez Cristina S. Barroso Deanna M. Hoelscher 《Journal of immigrant and minority health / Center for Minority Public Health》2010,12(5):769-780
Research on physical activity (PA) by level of acculturation in Hispanic children is limited and findings have been mixed.
We examined PA participation by primary language used with parents in a representative sample of 4th, 8th, and 11th grade
Texas public school students. Mixed-effects regression models were conducted using cross-sectional data from the 2004–2005
School Physical Activity and Nutrition Study (n = 22,049). Self-reported PA was compared among three language-ethnic groups: Spanish-Hispanic (SH) (referent); English-Hispanic
(EH); and English-Other (EO). EH and/or EO girls were generally between 1.25 and 2.58 [OR] times more likely to participate in PA across grade levels,
with the largest differences found for school sports in 8th grade girls. EH and EO 8th grade boys were 1.71 (CI: 1.40, 2.10)
and 2.06 (CI: 1.68, 2.51) times, respectively, more likely to participate in school sports. Findings indicate important disparities
in Spanish-speaking Hispanic children’s PA participation. 相似文献
7.
8.
Dietmar Winkler Matth?us Willeit Rainer Wolf Mara Stamenkovic Johannes Tauscher Edda Pjrek Anastasios Konstantinidis Shird Schindler Christian Barnas Siegfried Kasper 《European neuropsychopharmacology》2003,13(2):129-134
The value of a long-term treatment with clonazepam in the prophylaxis of affective disorder is discussed controversially in the scientific literature. Altogether there are only a few reports on the use of this compound as a mood stabilizer, most of them describing patients suffering from bipolar affective disorder. The aim of this investigation was to evaluate clonazepam as a phase prophylactic medication in affective disorder. We conducted a retrospective chart review in 34 out-patients of our lithium clinic (15 suffering from unipolar depression, 15 from bipolar disorder, four from schizoaffective disorder), who had been treated with clonazepam as a long-term medication. Clonazepam was either given as monotherapy, or as in the case of lithium non-responders, as adjunctive therapy. Patients with unipolar depression had significantly (P=0.026) less depressive episodes after initiation of treatment with clonazepam. Patients with bipolar disorder did not benefit from this therapy. Neither manic/hypomanic phases nor depressive episodes were reduced in this group of patients. Interestingly, clonazepam also reduced affective phases in our four schizoaffective patients on a trend level. Our results indicate that patients with unipolar depression may benefit from a maintenance treatment with clonazepam. Due to methodological limitations our results need to be replicated in controlled double-blind randomized clinical trials. 相似文献
9.
10.
Effect of dialysis flux and membrane material on dyslipidaemia and inflammation in haemodialysis patients. 总被引:4,自引:0,他引:4
Christoph Wanner Udo Bahner Renate Mattern Dietmar Lang Jutta Passlick-Deetjen 《Nephrology, dialysis, transplantation》2004,19(10):2570-2575
BACKGROUND: Dyslipidaemia, inflammation and oxidative stress are prominent risk factors that potentially cause vascular disease in haemodialysis patients. Dialysis modalities affect uraemic dyslipidaemia, possibly by modifying oxidative stress, but the effects of dialyser flux and membrane material on atherogenic remnant particles and oxidized low-density lipoproteins (LDL) are unknown. METHODS: We performed a randomized crossover study in 36 patients on haemodialysis to analyse the effect of dialyser flux and membrane material on plasma lipids, apolipoproteins and markers of inflammation and oxidative stress. Stable patients on low-flux dialysis with polysulphone for >/=6 weeks were assigned to high-flux polysulphone or high-flux modified cellulose with similar dialyser surface area and permeability characteristics and crossed over twice every 6 weeks. RESULTS: Thirty patients completed the study per protocol. Treatments with high-flux polysulphone and modified cellulose lowered serum triglyceride (by 20% and 10%, respectively; P<0.05) and remnant-like particle cholesterol by 32% (P<0.001) and 11% (NS) after the first 6 weeks of treatment. Oxidized LDL decreased significantly with high-flux polysulphone, but not with modified cellulose. Apolipoproteins CII and CIII were reduced, whereas the ratio CII/CIII was increased (all P<0.05). Acute-phase proteins and LDL and high-density lipoprotein cholesterol remained unaffected. CONCLUSIONS: This randomized crossover study demonstrates a potent effect of high-flux haemodialysis on uraemic dyslipidaemia. Polysulphone membrane material showed superiority on oxidatively modified LDL, an indicator of oxidative stress in haemodialysis patients. 相似文献