全文获取类型
收费全文 | 586篇 |
免费 | 52篇 |
国内免费 | 105篇 |
专业分类
儿科学 | 33篇 |
妇产科学 | 6篇 |
基础医学 | 62篇 |
口腔科学 | 32篇 |
临床医学 | 121篇 |
内科学 | 122篇 |
皮肤病学 | 7篇 |
神经病学 | 29篇 |
特种医学 | 76篇 |
外科学 | 57篇 |
综合类 | 40篇 |
预防医学 | 42篇 |
眼科学 | 5篇 |
药学 | 69篇 |
中国医学 | 1篇 |
肿瘤学 | 41篇 |
出版年
2022年 | 4篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 11篇 |
2016年 | 9篇 |
2015年 | 14篇 |
2014年 | 7篇 |
2013年 | 23篇 |
2012年 | 18篇 |
2011年 | 22篇 |
2010年 | 24篇 |
2009年 | 25篇 |
2008年 | 6篇 |
2007年 | 65篇 |
2006年 | 16篇 |
2005年 | 30篇 |
2004年 | 25篇 |
2003年 | 15篇 |
2002年 | 17篇 |
2001年 | 9篇 |
2000年 | 19篇 |
1999年 | 8篇 |
1998年 | 48篇 |
1997年 | 35篇 |
1996年 | 38篇 |
1995年 | 18篇 |
1994年 | 23篇 |
1993年 | 15篇 |
1992年 | 13篇 |
1991年 | 8篇 |
1990年 | 12篇 |
1989年 | 15篇 |
1988年 | 15篇 |
1987年 | 14篇 |
1986年 | 14篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1977年 | 4篇 |
1976年 | 10篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1973年 | 8篇 |
1970年 | 2篇 |
1966年 | 3篇 |
排序方式: 共有743条查询结果,搜索用时 15 毫秒
91.
抗病毒药物2,5,6-三取代-4(3H)嘧啶酮衍生物的合成及诱导干扰素活性 总被引:2,自引:0,他引:2
In order to search for more ideal antiviral drugs,21 substituted pyriiT1idinone derivatives were designed and synthesized,among which 11 were not reported before. The cheinicalstructures were characterized by elemen tal and spectral analysis. The serum interferon - inducing activity was tested in mice. All 2-amino-5-bromo-6-substituted-4-(3H)pyrimidinone compounds were shown to have interferon inducing activity.The corresponding substituted pyrimidine thiones were less active.The new compounds of 6-sulfophenyl derivatives are soluble in、water, but the interferon-inducing activity are not higher than the original compound of ABPP. 相似文献
92.
抗病毒药物2,5,6-三取代-4(3H)嘧啶酮衍生物的合成及诱导干扰素活性刘新泳,徐丽君(山东医科大学药学系济南250012)取代嘧啶酮类化合物是一类小分干扰素诱导剂,有抗病毒、抗肿瘤、杀菌抑霉、诱导干扰素和白介素、免疫调节等多种生物活性(1)。目前?.. 相似文献
93.
新型缩氨基硫脲衍生物——氨基巯三唑Schiff碱的合成与抗菌活性 总被引:7,自引:0,他引:7
设计合成了新型缩氨基硫脲衍生物4-氨基-3-(呋喃-2)-5-巯基-1,2,4-三唑及其十种不同醛的Schiff碱衍生物,并进行了抑菌实验。结果表明:Schiff碱化合物结构中的甲亚胺基是该类化合物的活性功能基。苯环上更换不同的取代基对其活性有一定的影响,其中化合物4-(5-硝基亚糠基氨基)-3-(呋喃-2)-5-巯基-1,2,4-三唑(Ik)抗菌活性最高且抗菌谱最广;化合物4-亚水杨基氨基-3-(呋喃-2)-5-巯基-1,2,4-三唑(Ib)具有较强的抑霉活性。 相似文献
94.
95.
The effect of cyclodextrin (beta-CD) on the solubility and dissolution rate of various paracetamol dispersion powders (1:1 w/w), and tablets was studied. Lower solubility was exhibited by a spray dried solid dispersion made from paracetamol-Ethocel-Macrogol 6000 (95:2:3). The improvement in solubility was influenced by complexation with beta-CD and the crystalline nature of the powder products made by different procedures. The difference in crystallinity was confirmed by X-ray powder diffraction patterns. The dissolution rate of paracetamol from tablets made from the solid dispersions was satisfactory compared with paracetamol alone. The differences between the dissolution rate from the examined paracetamol tablets resulted from the different solubility of each powder and from the structural changes of particles which influenced the consolidation of the tablet mass. 相似文献
96.
Douglas E. Holt Susan M. Hiniker John A. Kalapurakal John C. Breneman Jay C. Shiao Nicole Boik Benjamin T. Cooper Paige L. Dorn Matthew D. Hall Natalie Logie John T. Lucas Iain J. MacEwan Adam C. Olson Joshua D. Palmer Samir Patel Luke E. Pater Stephanie Surgener Derek S. Tsang Sarah A. Milgrom 《International journal of radiation oncology, biology, physics》2021,109(2):505-514
97.
In human immune deficiency virus (HIV)-seropositive hemophilia patients, a low number of CD4 + lymphocytes is found, as well as a low CD4+/CD8+ ratio. In previous studies, it has been shown that antigen- specific T-helper cell (CD4+) function was present and no excessive antigen-specific T-suppressor cell (CD8+) function could be demonstrated. In this report, we studied another activity of CD4+ cells, namely the capacity to induce T-suppressor cell activity. The results clearly show a selective dysfunction of CD4+ suppressor-inducer (Tsi) cell function. Since these HIV-seropositive hemophilia patients showed the presence of activated B cells in the peripheral circulation refractory to antigen-specific T-helper cell signals and secreting specific antibodies spontaneously, we raised the hypothesis that the activated B cells in the patients activate the Tsi cells in vivo. This constant activation leads to a functional exhaustion of the Tsi cell pool. 相似文献
98.
99.
Andrew J Boyle Stefania Di Gangi Umar I Hamid Linda-Jayne Mottram Lia McNamee Griania White LJ Mark Cross James J McNamee Cecilia M O’Kane Daniel F McAuley 《Critical care (London, England)》2015,19(1)
IntroductionAcute respiratory distress syndrome (ARDS) is a common clinical syndrome with high mortality and long-term morbidity. To date there is no effective pharmacological therapy. Aspirin therapy has recently been shown to reduce the risk of developing ARDS, but the effect of aspirin on established ARDS is unknown.MethodsIn a single large regional medical and surgical ICU between December 2010 and July 2012, all patients with ARDS were prospectively identified and demographic, clinical, and laboratory variables were recorded retrospectively. Aspirin usage, both pre-hospital and during intensive care unit (ICU) stay, was included. The primary outcome was ICU mortality. We used univariate and multivariate logistic regression analyses to assess the impact of these variables on ICU mortality.ResultsIn total, 202 patients with ARDS were included; 56 (28%) of these received aspirin either pre-hospital, in the ICU, or both. Using multivariate logistic regression analysis, aspirin therapy, given either before or during hospital stay, was associated with a reduction in ICU mortality (odds ratio (OR) 0.38 (0.15 to 0.96) P = 0.04). Additional factors that predicted ICU mortality for patients with ARDS were vasopressor use (OR 2.09 (1.05 to 4.18) P = 0.04) and APACHE II score (OR 1.07 (1.02 to 1.13) P = 0.01). There was no effect upon ICU length of stay or hospital mortality.ConclusionAspirin therapy was associated with a reduced risk of ICU mortality. These data are the first to demonstrate a potential protective role for aspirin in patients with ARDS. Clinical trials to evaluate the role of aspirin as a pharmacological intervention for ARDS are needed. 相似文献
100.