全文获取类型
收费全文 | 8872篇 |
免费 | 551篇 |
国内免费 | 155篇 |
专业分类
耳鼻咽喉 | 120篇 |
儿科学 | 151篇 |
妇产科学 | 104篇 |
基础医学 | 1309篇 |
口腔科学 | 181篇 |
临床医学 | 755篇 |
内科学 | 1864篇 |
皮肤病学 | 192篇 |
神经病学 | 583篇 |
特种医学 | 597篇 |
外国民族医学 | 2篇 |
外科学 | 1286篇 |
综合类 | 151篇 |
预防医学 | 579篇 |
眼科学 | 216篇 |
药学 | 739篇 |
1篇 | |
中国医学 | 143篇 |
肿瘤学 | 605篇 |
出版年
2023年 | 78篇 |
2022年 | 277篇 |
2021年 | 376篇 |
2020年 | 181篇 |
2019年 | 255篇 |
2018年 | 270篇 |
2017年 | 198篇 |
2016年 | 315篇 |
2015年 | 400篇 |
2014年 | 483篇 |
2013年 | 541篇 |
2012年 | 862篇 |
2011年 | 756篇 |
2010年 | 376篇 |
2009年 | 355篇 |
2008年 | 531篇 |
2007年 | 427篇 |
2006年 | 427篇 |
2005年 | 350篇 |
2004年 | 335篇 |
2003年 | 328篇 |
2002年 | 260篇 |
2001年 | 178篇 |
2000年 | 164篇 |
1999年 | 149篇 |
1998年 | 77篇 |
1997年 | 50篇 |
1996年 | 45篇 |
1995年 | 38篇 |
1994年 | 23篇 |
1993年 | 25篇 |
1992年 | 32篇 |
1991年 | 42篇 |
1990年 | 25篇 |
1989年 | 28篇 |
1988年 | 30篇 |
1987年 | 25篇 |
1986年 | 26篇 |
1985年 | 26篇 |
1984年 | 17篇 |
1983年 | 21篇 |
1982年 | 15篇 |
1981年 | 12篇 |
1980年 | 12篇 |
1979年 | 17篇 |
1978年 | 11篇 |
1976年 | 10篇 |
1974年 | 9篇 |
1970年 | 12篇 |
1968年 | 9篇 |
排序方式: 共有9578条查询结果,搜索用时 15 毫秒
11.
Soo Hyun Kim Yang-Kyoo Han Young Ha Kim Sung Ill Hong 《Macromolecular chemistry and physics.》1992,193(7):1623-1631
L -Lactide was polymerized with stannous 2-ethylhexanoate (stannous octoate) in the presence of pentaerythritol to investigate multifunctional initiation. The prepared oligomers contain starshaped 4-arm molecules when the mole ratio of [lactide]/[pentaerythritol] is above 32. The molecular weight of oligomers coincides with the [lactide]/[pentaerythritol] ratio, indicating that pentaerythritol in conjugation with stannous octoate is an initiator for the “living” polymerization of L-lactide. 相似文献
12.
Jeong-Hyup Ha Seung-Jae Lee Myoung-Seon Gong 《Macromolecular chemistry and physics.》1995,196(12):4001-4010
Poly(enaminonitriles) containing flexible alkyl ether units were prepared by reacting p-bis(1-chloro-2,2-dicyanovinyl)benzene with various α,ω-bis(4-aminophenoxy)alkanes in N-methyl-2-pyrrolidone (NMP). All the polymers are soluble in polar aprotic solvents such as N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc) and NMP as well as in common organic solvents such as tetrahydrofuran and acetone. High molecular weight polymers possessing inherent viscosities in the range of 0.82–1.20 dL/g were obtained and tough films were cast from a DMF solution. They showed a large exotherm around 340°C attributable to the chemical changes of the dicyanovinyl group. Thermogravimetric analyses exhibited a good thermal stability with a 10% weight loss around 450°C and 73–88% residual weight at 500°C under nitrogen. 相似文献
13.
Mercury concentration was determined in the caps and stalks of nine species of edible mushrooms collected at the area of Wieluńska Upland in district of Czestochowa in 1995-96. The mushroom species examined were such as: yellow-cracking bolete Xerocomus subtomentosus, brown birch scaber stalk Leccinum scabrum, slippery Jack Suillus luteus, larch bolete Suillus grevillei, gray knight-cap Tricholoma terreum, parasol mushroom Macrolepiota procera, horse mushroom Agaricus arvensis, fennel funnel cap Clitocybe odora, fairy-ring mushroom Marasmius oreades and tacky green brittle gills Russula aereuginea. The method of mercury measurement was cold-vapour atomic absorption spectroscopy (CV-AAS) after wet digestion of the samples with concentrated nitric acid in a whole glass system. The parasol mushroom and horse mushroom showed a highest mercury concentrations and contained, respectively, 4500 +/- 1700 and 4400 +/- 2400 ng/g dry wt in caps, and 2800 +/- 1300 and 2800 +/- 2100 ng/g dry wt in stalks. In the case of fennel funnel cap and fairy-ring mushroom the mean total mercury concentrations in caps was above 500 ng/g dry wt, and for other species were between 150 +/- 50 and 500 +/- 230 ng/g dry wt. The stalks of the mushroom species examined in all cases showed lower contamination with mercury than caps. The mean total mercury concentrations noted in caps and stalks of mushrooms examined were usually higher than was reported till now in the same species elsewhere in Poland, while a maximum values found in an individual fruiting bodies are within the range of the concentrations noted in specimens collected from an unpolluted areas. 相似文献
14.
Obesity as psychosomatic disease is a mass phenomenon. The number of obese males (BMI > 30) became doubled in the last ten years. In the etiology of obesity play an important role the reactive obesity. In the background of "yo-yo syndrome" often could be found depression, or other psychotic disorder. The low self-esteem, body dissatisfaction, tension, anxiety disorders is well-known in a slimming diet. Obese subjects (n = 29) who were admitted on their request with a view to losing weight were examined (Hamilton Depressive Scala, Hamilton Anxietas Scala, Eating Attitude Test) Physical Conditioning and internal Medicine Department of National Sports Medicine Institute, Budapest. Among obesities with mild and severe depression as treatment of somatic complications was used fluoxetine, in severe cases and depression with severe anxiety was associated with supportive or cognitive-behavioral treatment. The prevalence of binge eating disorders were at 57% and bulimia nervosa was at 3% in using population (n = 29). Decreasing of anxiety and grade of depression significantly correlated with body mass index (p < 0.023, F = 1.997, p < 0.034, F = 3.131). The treatment of fluoxetine significantly correlated with body mass index (T1: p < 0.023, T2: p < 0.03, T3: p < 0.004). The patients indicated their well being as fluoxetine reduced eating, satiety and lower binges. 相似文献
15.
16.
E. Imhof S. Elsasser B. Rosmus H. R. Ha F. Follath A. P. Perruchoud 《European journal of clinical pharmacology》1991,41(4):317-319
Summary A single oral dose of verapamil 80 mg was shown significantly to inhibit histamine-induced bronchoconstriction in 8 out of 16 asthmatic subjects (maximum increase in PD20FEVHi 416%). There was still significant protection ( PD20FEV1Hi>100%) in the responders 5 h after the oral dose. The relationship of the bronchoprotective effect to the plasma level of verapamil was also examined. Responders and non-responders did not differ significantly in the peak plasma level or the time course of the plasma verapamil concentration.The protective effect was not correlated with the peak plasma level of verapamil or with the baseline bronchial hyperreactivity. 相似文献
18.
Lung involvement in Langerhans' cell histiocytosis: prevalence, clinical features, and outcome. 总被引:1,自引:0,他引:1
In Langerhans' cell histiocytosis, the prognostic significance of pulmonary disease is controversial. The clinical and radiological features and lung function tests of Langerhans' cell histiocytosis patients presenting to a single tertiary referral center between 1981 and 1987 were reviewed. Age at diagnosis ranged from 2 weeks to 16 years (median 1.7 years) and the male-female ratio was 2.4:1. No child presented with lung involvement alone. In 18 (40%) of 45 patients with multisystem disease there was clinical and/or radiological evidence of lung pathology. Another 6 children (13%) with normal chest roentgenograms had abnormal lung function tests, suggesting subclinical ("occult") involvement. Those with overt lung disease tended to present at a younger than average age (median 0.6 years). The most common functional disturbance was reduced lung or respiratory compliance with reduced lung volumes. Patients with and without lung involvement showed a similar pattern of involvement of other organs, with skin and bone most commonly affected. Of the 45 children with multisystem disease, 38 (84%) survived 2 to 7 years after diagnosis; there was a similar proportion of deaths in children with and without lung involvement. It is concluded that lung involvement occurs in nearly half of young children with multisystem Langerhans' cell histiocytosis but does not adversely affect outcome. 相似文献
19.
M Go?ebiowska I Ligenza I Kobierska E Zielińska J Wlaz?owski P Sikora K Ha?adaj 《Ginekologia polska》1992,63(5):221-226
1110 neonates, from 30 to 42 of estimated gestational age (EGA) were measured on the 1st day of life to estimate upper mid-arm circumference (MAC) and head circumference (HC). Individual MAC/HC ratio was calculated. MAC/HC ratio was used to estimate gestational age and nutritional status of the newborns. We proved that MAC/HC ratio increased linearly between 30 and 38 week of pregnancy and it stabilized between 38-42 week. We compared MAC/HC ratio with birth weight, skin fold score, and ponderal index. We concluded that this ratio may be very useful to estimate gestational age and to include the neonates to "the group of risk". 相似文献
20.
Poly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear enzyme, activated by DNA strand breaks to participate in DNA repair. Overactivation of PARP by cellular insults depletes its substrate NAD(+) and then ATP, leading to a major energy deficit and cell death. This mechanism appears to be prominent in vascular stroke and other neurodegenerative processes in which PARP gene deletion and PARP-inhibiting drugs provide major protection. Cell death associated with PARP-1 overactivation appears to be predominantly necrotic while apoptosis is associated with PARP-1 cleavage, which may conserve energy needed for the apoptotic process. Novel forms of PARP derived from distinct genes and lacking classic DNA-binding domains may have nonnuclear functions, perhaps linked to cellular energy dynamics. 相似文献