全文获取类型
收费全文 | 1166篇 |
免费 | 86篇 |
国内免费 | 157篇 |
专业分类
儿科学 | 2篇 |
基础医学 | 56篇 |
口腔科学 | 3篇 |
临床医学 | 31篇 |
内科学 | 45篇 |
皮肤病学 | 7篇 |
神经病学 | 9篇 |
特种医学 | 11篇 |
外科学 | 11篇 |
综合类 | 199篇 |
预防医学 | 16篇 |
眼科学 | 3篇 |
药学 | 479篇 |
1篇 | |
中国医学 | 522篇 |
肿瘤学 | 14篇 |
出版年
2024年 | 4篇 |
2023年 | 18篇 |
2022年 | 27篇 |
2021年 | 35篇 |
2020年 | 37篇 |
2019年 | 40篇 |
2018年 | 48篇 |
2017年 | 64篇 |
2016年 | 66篇 |
2015年 | 49篇 |
2014年 | 110篇 |
2013年 | 143篇 |
2012年 | 88篇 |
2011年 | 85篇 |
2010年 | 58篇 |
2009年 | 58篇 |
2008年 | 61篇 |
2007年 | 47篇 |
2006年 | 51篇 |
2005年 | 36篇 |
2004年 | 22篇 |
2003年 | 29篇 |
2002年 | 24篇 |
2001年 | 24篇 |
2000年 | 12篇 |
1999年 | 19篇 |
1998年 | 4篇 |
1997年 | 9篇 |
1996年 | 8篇 |
1994年 | 12篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1982年 | 7篇 |
1981年 | 8篇 |
1980年 | 5篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1975年 | 4篇 |
1974年 | 5篇 |
1972年 | 3篇 |
1971年 | 3篇 |
排序方式: 共有1409条查询结果,搜索用时 15 毫秒
1.
目的 从福参Angelica morii提取分离活性成分。方法 采用乙醇提取,溶剂萃取,大孔树脂、聚酰胺、硅胶柱层析,LH-20、重结晶等纯化,对福参饮片进行系统提取分离;运用波谱学方法及理化常数对照进行结构鉴定。结果 从正丁醇和水部分分离到6个苷类化合物,分别为升麻索苷(prim-O-glucosylcimifugin,Ⅰ)、紫花前胡苷(marmesinin,Ⅱ)、芹菜素7-O-β-D-葡萄糖苷(apigenin 7-O0-β-D-glucoside,Ⅲ)、木犀草素7-O-β-D-葡萄糖苷(1ute—olin 7-O-β-D-glucoside,Ⅳ),umbeliferone 7-apiosylglucoside(V)和胡萝卜苷(daucosterol,Ⅵ)。结论 6个化合物均为首次该植物中分得;化合物Ⅲ首次从当归属中分得。 相似文献
2.
K. CHEUNG R. URECH L. TAYLOR P. DUFFY D. RADFORD 《Journal of paediatrics and child health》1991,27(5):312-313
The potential application of the Digoxin Fab antibody (Wellcome Digibind) in the clinical management of plant poisoning was investigated. The cardiac glycoside contents of various Australian plants were studied using immunoassay techniques. The cross-reactions of the Fab antibody and two digoxin assay antibodies against extracts of these plants were also studied. Results obtained indicated that the Digibind antibody cross-reacted with a wide range of glycosides contained in Australian plants and therefore could be of use in the treatment of life-threatening plant poisoning. 相似文献
3.
E. Casari M. Alfano M. Valente G. D. Clarke G. Ferni V. Grazioli 《Osteoporosis international》1997,7(6):539-543
The ovariectomized rat is the most commonly used animal model of human postmenopausal osteoporosis, exhibiting a high rate
of bone turnover with resorption exceeding formation. At present, bone turnover is quantified directly by dynamic histomorphometry.
The aim of the present study was to determine whether the measurement of the urinary output of some specific bone collagen
catabolites — pyridinolines and hydroxylysine glycosides — could be used to indirectly monitor the initial phase of bone turnover
increase in ovariectomized 90-day-old rats. Ninety-day-old female rats were randomly divided into three groups (n=6): ovariectomized, sham-operated and non-treated controls. Urine samples (24 h) were collected 6 days before surgery and
twice weekly for the 4 weeks following ovariectomy. Urinary excretion of pyridinoline (PYD), deoxypyridinoline (DPD), glucosyl-galactosyl-hydroxylysine
(GGHYL) and galactosyl-hydroxylysine (GHYL) were measured. As expected, ovariectomy was associated with a significant decrease
in bone mineral density in both the proximal tibial and distal femoral metaphysis. Compared with both sham-operated and control
animals, ovariectomized rats showed significant increases in PYD, GGHYL and GHYL urinary output 8 days after surgery and in
DPD output after 15 days. These changes were maintained throughout the study. The results confirm that measurement of the
urinary excretion of pyridinolines and hydroxylysine glycosides represents a powerful tool for detecting the onset of bone
turnover in ovariectomized 90-day-old rats. 相似文献
4.
作者采用正文试验法,以水提醇沉法提取和分离酚戒类有效成分,并以苯乙醇成含量作为含量测定指标,考察了乙醇浓度、提取温度及煎煮时间三个因素对有效成分提取量的影响,从而筛选出芸杞补肾口服液的是佳生产工艺。 相似文献
5.
肉苁蓉总苷对阿霉素所致小鼠心肌毒性的保护作用 总被引:7,自引:1,他引:6
目的:探讨肉苁蓉总苷(GCs)对阿霉素(Dox)所致小鼠心肌损害的保护作用及其机制。方法:选用NIH小鼠一次腹腔注射Dox(17.5mg/kg)造成急性心肌损伤模型,测定心肌超氧化物歧化酶(SOD)活性;硒-谷胱苷肽过氧化物酶(Se-GSH-Px)活性;丙二醛(MDA)含量及血清肌酸磷酸激酶(CPK)活性。电镜检查心肌细胞超微结构的改变。结果:腹腔注射Dox 48h后可致小鼠心肌明显损害,心肌SOD及Se-GSH-Px活性下降,MDA含量升高,血清中CPK的活性增强,同时出现心肌组织超微结构的损伤。GCs(62.5、125.0、250.0mg/kg)能增加心肌SOD、Se-GSH-Px活性,降低MDA含量,减少CPK释放,减轻心肌超微结构的损伤。结论:肉苁蓉总苷对阿霉素所致心肌损害有一定的保护作用,其机制可能与其保护心肌SOD及Se-GSH-Px活性及其清除自由基,防止脂质过氧化有关。 相似文献
6.
7.
Summary The time course of the reversal of toxic and nontoxic effects of digoxin by digoxin-specific antibody fragments (Fab) was measured in isolated human ventricular myocardium. A concentration of 2×10–6 mol/l digoxin was used to produce positive inotropy followed by mechanical signs of toxicity. After addition of a 1.5-fold higher molar concentration of digoxin-specific Fab, signs of toxicity disappeared within 30 min and digoxin-induced force of contraction decayed with a monoexponential time course with a half-life of 52 min. This rate of decay was almost identical to that observed for the dissociation of the digoxin-(Na++K+)-ATPase complex in human heart cell membranes. It is concluded that (a) digoxin-specific Fab are capable of completely removing digoxin from its binding sites, (b) the maximal rate of removal of digitalis glycosides from the (Na++K+)-ATPase is limited by the dissociation rate constant, and (c) there is a close correlation between the degree of binding of digitalis glycosides to the (Na++K+)-ATPase and the increase in force of contraction.Abbreviation Fab
Fragment antibody binding (digitalis antidote) 相似文献
8.
. ELLINGSEN O. M. SEJERSTED O. A. VENGEN A. ILEBEKK 《Acta physiologica (Oxford, England)》1989,135(4):493-503
Maintenance of adequate electrical activity of the heart depends critically on the ability of the Na-K pump to compensate for normal passive sodium and potassium fluxes. Using sudden injections of [3H]ouabain into the left coronary artery in anaesthetized open-chest pigs, we monitored transient changes in myocardial potassium balance by PVC-valinomycin mini-electrodes. When related to the number of pumps blocked and fractional inhibition, these data provided estimates of total Na-K pump capacity as well as actual pump rate and perturbations of the Na-K balance. Experiments were performed in hearts with and without intracoronary isoprenaline infusion (2.5 nmol min-1). After injection of 120 nmol [3H]ouabain into the left coronary artery, myocardial [3H]ouabain concentrations were 118 (74–178) and 103 (76–145) pmol g-1 and total concentrations of [3H]oubain binding sites were 893 (752–1076) and 785 (691–877) pmol g-1 (median, 95% confidence interval) in isoprenaline-treated and control hearts respectively (differences not significant). The [3H]ouabain injection caused a net potassium release of 81 (56–132) and 43 (23–75) μcool 100 g-1 (median, 95% confidence interval) in isoprenaline-treated and control hearts respectively (n= 6–8; significance of difference, P= 0.03). Na–K pump rate estimated from mono-exponential release curves was 6363 (3942–10,858) K+ ions min-1 site-1 during β-adrenoceptor stimulation and 2514 (1380–4322) in control (significance of difference, P= 0.03). This corresponds to 40 and 16%, respectively, of the maximum possible pump rate determined from ATP hydrolysis. Comparison of accumulated potassium release and relative Na-K pump rate indicates that catecholamines enhance the sensitivity of the Na-K pump for intracellular sodium. 相似文献
9.
D. Lang G. G. Belz R. Hofstetter U. Töllner G. von Bernuth 《Journal of molecular medicine (Berlin, Germany)》1976,54(8):389-390
Summary Serum digoxin concentration and half-life were radioimmunologically determined in 9 mature newborns after 7 days medication with digoxin. The newborns were in respiratory distress treated with continuous positive airway pressure or were suspected to have serious congenital heart disease. Loading dose was 26 µg/kg body weight intravenously and 35 µg/kg body weight orally, respectively. Maintenance dose corresponded to 1/8th of the digitalization dose twice daily.The serum digoxin level 12 h after the last dose varied between 1.4 and 2.5 ng/ml (mean 2.0 ng/ml, Sx=0.4). The serum half-life of digoxin varied between 21.7 and 42.4 h (mean 30.0 h, Sx=7.7). The mean serum half-life of digoxin of 30 h attained values found in adults without renal disease. This suggests that the serum digoxin levels of newborns which are usually higher if compared with those of adults result from higher digoxin doses per unit body weight and not from diminished digoxin elimination. 相似文献
10.
Summary Active ion transport in the colon is generating a transmucosal electrical potential difference (PD) of about 40 mV. Cathartic agents inhibit electrolyte and water net-absorption or cause net-secretion which should be reflected in a change of PD.In 83 normal subjects the effect of an isotonic eletrolyte solution (control) and different cathartic agents on rectal PD was tested: Laxatives (bisacodyl, rhein), bile acids (cholic and deoxycholic acid), fatty acids (oleic and ricinoleic acid) and cardiac glycosides (meproscillarin, digitoxin, digoxin). Bisacodyl, deoxycholic acid in high concentration, meproscillarin and digitoxin significantly decreased PD, while the other substances did not.Cathartics act on different transport mechanisms which together with different absorption characteristics of the proximal and distal colon may explain the difference in effecting the PD. Rectal PD measurement provides an easy and convenient tool to document effects of cathartic agents on electrolyte transport, otherwise difficult to obtain, and is applicable for clinical use.To Prof. Dr. H.P. Wolff on the occasion of his 65th birthday 相似文献