全文获取类型
收费全文 | 9174篇 |
免费 | 674篇 |
国内免费 | 54篇 |
专业分类
耳鼻咽喉 | 209篇 |
儿科学 | 299篇 |
妇产科学 | 240篇 |
基础医学 | 1152篇 |
口腔科学 | 228篇 |
临床医学 | 923篇 |
内科学 | 1880篇 |
皮肤病学 | 58篇 |
神经病学 | 916篇 |
特种医学 | 424篇 |
外国民族医学 | 2篇 |
外科学 | 1382篇 |
综合类 | 166篇 |
一般理论 | 6篇 |
预防医学 | 818篇 |
眼科学 | 139篇 |
药学 | 542篇 |
2篇 | |
中国医学 | 9篇 |
肿瘤学 | 507篇 |
出版年
2021年 | 111篇 |
2020年 | 78篇 |
2019年 | 126篇 |
2018年 | 125篇 |
2017年 | 90篇 |
2016年 | 98篇 |
2015年 | 159篇 |
2014年 | 187篇 |
2013年 | 252篇 |
2012年 | 366篇 |
2011年 | 428篇 |
2010年 | 263篇 |
2009年 | 238篇 |
2008年 | 370篇 |
2007年 | 417篇 |
2006年 | 341篇 |
2005年 | 371篇 |
2004年 | 337篇 |
2003年 | 331篇 |
2002年 | 338篇 |
2001年 | 288篇 |
2000年 | 277篇 |
1999年 | 241篇 |
1998年 | 120篇 |
1997年 | 115篇 |
1996年 | 107篇 |
1995年 | 115篇 |
1994年 | 114篇 |
1993年 | 101篇 |
1992年 | 215篇 |
1991年 | 217篇 |
1990年 | 212篇 |
1989年 | 216篇 |
1988年 | 203篇 |
1987年 | 207篇 |
1986年 | 200篇 |
1985年 | 182篇 |
1984年 | 139篇 |
1983年 | 118篇 |
1982年 | 83篇 |
1980年 | 77篇 |
1979年 | 130篇 |
1978年 | 99篇 |
1977年 | 71篇 |
1976年 | 84篇 |
1975年 | 86篇 |
1974年 | 79篇 |
1973年 | 76篇 |
1972年 | 90篇 |
1971年 | 75篇 |
排序方式: 共有9902条查询结果,搜索用时 15 毫秒
11.
A model for training the trainers of child care providers that employs Vygotsky's framework of the Zone of Proximal Development is described. This efficient training mechanism proposes mentoring relationships as a means to meet the developmental needs of experienced child care professionals and improve the quality of existing child care programs.The authors would like to thank Dr. Bille Thomas and the satellite resource center directors and staff members for their work on the project. 相似文献
12.
Interaction between insulin and glucose-delivery route in regulation of net hepatic glucose uptake in conscious dogs 总被引:5,自引:0,他引:5
B A Adkins-Marshall S R Myers G K Hendrick P E Williams K Triebwasser B Floyd A D Cherrington 《Diabetes》1990,39(1):87-95
In the presence of fixed basal levels of insulin, the route of intravenous glucose delivery (protal vs. peripheral) determines whether net hepatic glucose uptake (NHGU) occurs. Our aims were to determine if the route of intravenous glucose delivery also plays a role in regulating NHGU in the presence of hyperinsulinemia and to determine if length of fast (18 vs. 36 h) influences regulation of NHGU. Five conscious dogs fasted 18 h were given somatostatin and replacement insulin (245 +/- 34 microU.kg-1.min-1) and glucagon (0.65 ng.kg-1.min-1) infusions intraportally. After a 40-min control period, the insulin infusion rate was increased fourfold, and glucose was infused for 3 h. Glucose was given either through a peripheral vein or the portal vein for 90 min to double the glucose load reaching the liver. The order of infusions was randomized. NHGU was measured with the arterial - venous difference technique. Insulin and glucagon levels were 12 +/- 2, 35 +/- 6, and 36 +/- 5 microU/ml and 55 +/- 12, 61 +/- 13, and 59 +/- 7 pg/ml during the control, peripheral, and portal infusions, respectively. The glucose infusion rate, the load of glucose reaching the liver, and the arterial-portal plasma glucose gradient were 0, 9.58 +/- 2.28, and 10.44 +/- 2.94 mg.kg-1.min-1; 29.4 +/- 3.6, 56.8 +/- 3.4, and 56.8 +/- 2.8 mg.kg-1.min-1; and 2 +/- 1, 5 +/- 1, and -51 +/- 15 mg/dl during the same periods.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
13.
14.
15.
Using the concepts of stigma, NIMBY and place, this paper examines the difficulties of finding a place for needle exchange programs (NEPs). Data were drawn from semi-structured interviews with NEP staff (Ontario, Canada) that focused on operational policies and routines. An iterative, inductive analytic process was used. NEPs, their staff and clients are not always welcome additions to organizations or communities because of concerns about the ‘dangerousness’ of clients and the potential contamination of communities and workplaces by stigmatized individuals and their artefacts (e.g. contaminated injection equipment). Public parks where a lot of drug ‘action’ takes place are good destinations for outreach workers but these places are contentious sites for NEP activities, particularly when residents do not perceive a need for the program and/or want to redefine their neighbourhoods. Issues of ‘place’ are further complicated when service delivery is mobile. Finding a place within organizations is difficult for NEPs because of concerns about the diversion of limited financial and spatial resources to ‘non-core’ activities and ‘undesirable’ clients. Workers respond to these challenges by contesting the social and spatial boundaries of who is an acceptable client or neighbour and refuting the perceived ‘differentness’ of injection drug users. Implementation of an unpopular service involves a delicate balancing act of interests, understanding of the dynamics of particular communities and a willingness to reinvent and redefine programs. The sociospatial stigmatization of injection drug use has had a negative impact on NEPs, and perhaps limits HIV prevention efforts. 相似文献
16.
Radiographic manifestations of bronchiolitis obliterans with organizing pneumonia vs usual interstitial pneumonia 总被引:1,自引:0,他引:1
P W Chandler M S Shin S E Friedman J L Myers A L Katzenstein 《AJR. American journal of roentgenology》1986,147(5):899-906
The radiographic findings in 24 cases of bronchiolitis obliterans with organizing pneumonia and 16 cases of usual interstitial pneumonia were reviewed and compared. Some cases of bronchiolitis obliterans with organizing pneumonia have been mistaken for usual interstitial pneumonia, although the two diseases have distinct pathologic findings. Clinically, the diseases often have different manifestations. Bronchiolitis obliterans with organizing pneumonia has a better prognosis and often responds well to steroids. This study shows that the radiologic findings of bronchiolitis obliterans include alveolar opacities without lung-volume loss. Patients with usual interstitial pneumonia, however, have bilateral diffuse interstitial opacities with occasional honeycomb changes, and there is loss of lung volume in most patients. These findings suggest that the chest radiograph can aid in distinguishing the two diseases. 相似文献
17.
18.
The purpose of this experiment was to determine the temporal characteristics associated with the age-related development of volitional consumption of ethanol induced by the pharmacological inhibition of aldehyde dehydrogenase (AlDH). To induce preference for ethanol, the AlDH inhibitor, cyanamide, was administered to male Sprague-Dawley rats which were 30 days of age. Cyanamide (n = 8) was injected subcutaneously twice daily in a dose of 10 mg/kg over a period of 3 days while the control group (n = 6) received the saline vehicle solution according to the same schedule. Then at 50, 70, 90, and 110 days of age, both groups of rats were given a standard 11-day test of preference for water versus ethanol offered in concentrations ranging from 3% through 30%. The results showed that at 70 days of age the preference for ethanol increased above the level of the 50-day test in terms of absolute g/kg intakes and proportion of ethanol to water consumed over the lower range of 3% through 15% concentrations. During the tests at 90 and 110 days of age, the cyanamide-treated rats further increased their preference for ethanol significantly over the levels at the 70-day test in terms of both g/kg and proportional intakes. The pattern of drinking of ethanol offered in the higher concentrations of 25% and 30% was unrelated to the age of the rats and the overall intakes were significantly higher than those of the lower concentrations. These findings demonstrate that the enzymatic inhibition of AlDH systematically acts in a delayed fashion to shift the pattern of preference for ethanol which is contingent on the maturation of the animal. In this instance, the volitional intake of ethanol in the cyanamide-treated rats reached its maximal level by 90-110 days of age. It is proposed that an endocrine mechanism involved in gonadal maturation may function in the intense shift in alcohol drinking. 相似文献
19.
M L Brooks D P Mayer R T Sataloff D L Myers J R Spiegel S Ruiz 《Computerized medical imaging and graphics》1992,16(4):283-285
A patient with a surgically proven intracanalicular arachnoid cyst was studied using computed tomography, magnetic resonance imaging, and air CT cisternography. The lesion had a similar radiographic appearance to acoustic neuroma and therefore, although rare, must be considered in the differential diagnosis of intracanalicular mass lesions. We report a case in which examination was performed, in evaluating the lesion, utilizing high-resolution air CT cisternography and magnetic resonance imaging (MRI). 相似文献
20.
高效液相色谱法测定右旋儿茶素血浆浓度及药代动力学参数 总被引:1,自引:0,他引:1
本文建立了体液中右旋儿茶素的RP-HPLC测定方法。采用C_(18)键合相硅胶为填料的固相提取柱进行样品预处理,右旋儿茶素的提取回收率为79.8%.应用二极管阵列检测器对色谱峰纯度进行鉴定。该法精密度好,方法回收率近100%,日内、日间的变异系数为2.4~5.6%,血浓69.6~1160 ng/ml范围内呈线性关系,r=0.9993。家兔静注右旋儿茶素18mg/kg,其药代动力学过程符合二室模型,分布相半衰期为0.129 h,消除相半衰期为1.19h。 相似文献