全文获取类型
收费全文 | 1527967篇 |
免费 | 94606篇 |
国内免费 | 1824篇 |
专业分类
耳鼻咽喉 | 20947篇 |
儿科学 | 48635篇 |
妇产科学 | 39524篇 |
基础医学 | 232491篇 |
口腔科学 | 40307篇 |
临床医学 | 137055篇 |
内科学 | 284518篇 |
皮肤病学 | 34335篇 |
神经病学 | 110391篇 |
特种医学 | 59970篇 |
外国民族医学 | 254篇 |
外科学 | 230184篇 |
综合类 | 28019篇 |
现状与发展 | 3篇 |
一般理论 | 360篇 |
预防医学 | 108215篇 |
眼科学 | 34960篇 |
药学 | 121094篇 |
8篇 | |
中国医学 | 3682篇 |
肿瘤学 | 89445篇 |
出版年
2018年 | 16053篇 |
2017年 | 12333篇 |
2016年 | 14100篇 |
2015年 | 15668篇 |
2014年 | 21231篇 |
2013年 | 31098篇 |
2012年 | 43791篇 |
2011年 | 46975篇 |
2010年 | 27432篇 |
2009年 | 25372篇 |
2008年 | 43333篇 |
2007年 | 47000篇 |
2006年 | 47130篇 |
2005年 | 44932篇 |
2004年 | 43287篇 |
2003年 | 41646篇 |
2002年 | 40184篇 |
2001年 | 78212篇 |
2000年 | 80136篇 |
1999年 | 66463篇 |
1998年 | 16870篇 |
1997年 | 14672篇 |
1996年 | 14681篇 |
1995年 | 13749篇 |
1994年 | 12417篇 |
1993年 | 11918篇 |
1992年 | 49819篇 |
1991年 | 49461篇 |
1990年 | 49089篇 |
1989年 | 47476篇 |
1988年 | 43024篇 |
1987年 | 42064篇 |
1986年 | 39376篇 |
1985年 | 37277篇 |
1984年 | 27177篇 |
1983年 | 23039篇 |
1982年 | 12400篇 |
1979年 | 24808篇 |
1978年 | 16946篇 |
1977年 | 14709篇 |
1976年 | 13609篇 |
1975年 | 15877篇 |
1974年 | 18202篇 |
1973年 | 17621篇 |
1972年 | 16630篇 |
1971年 | 15752篇 |
1970年 | 14563篇 |
1969年 | 13894篇 |
1968年 | 12577篇 |
1967年 | 11280篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
A K Siriwardena 《European journal of vascular surgery》1990,4(6):649-650
A case of blunt injury to the abdominal aorta is presented. A deceleration injury with seat-belt compression caused dislodgement of atheromatous fragments as emboli from an atherosclerotic aorta. Atherosclerosis is common, and the compulsory wearing of seat-belts may make this injury more frequent. 相似文献
152.
Aim : The study was designed to determine the effect of computerized nutrition information on consumer food choice in two workplace restaurants, one in which customers had to pay for their lunch and the other providing a free lunch. Methods : Customers entering the restaurants were asked to make selections from the menu on a computer screen. The energy, saturated fatty acids, non-milk extrinsic sugars and non-starch polysaccharide content of the meal selected was displayed graphically in proportion to the dietary reference values. They were given the opportunity to change their selected meal and the composition of all meals was recorded. Results : The nutritional composition of the first meal provoked 16% of customers to make a second selection. The proportion of energy in the first selection had been 31% higher for saturated fatty acids and 23% higher for non-milk extrinsic sugars than the first selection made by people who were satisfied with their first choice. In their second attempt they succeeded in reducing both nutrients to levels similar to those present in the meals selected by people who had been satisfied with their first selection. Customers>> selections for non-starch polysaccharide and energy did not differ between the groups. The main changes made by customers to achieve improved second choices were to omit dishes (44%), add dishes (19%), make changes within a menu category (46%), and make changes from one menu category to another (26%). Conclusion : It was concluded that provision of graphical nutrition information on a computer screen could be used by a subset of the users of both restaurants to enable them to improve their menu selections to a similar composition to that selected by the other people who used the computer system. 相似文献
153.
154.
OBJECTIVE: To determine the most frequent clinical causes of a prolonged activated partial thromboplastin time (APTT) result, and to determine whether a new heparin-removal device (the Hepchek, Pall Biomedical, Glen Cove, NY 11542) is capable of efficiently detecting the causes of these values. DESIGN: A combination of chart review and laboratory testing comparing the criterion standard--the heparin chromogenic substrate assay--with the Hepchek. Laboratory investigations were blinded and controlled. SETTING: Inpatient, acute-care hospital. PATIENTS: A total of 1,000 hospital patients with a variety of hemostatic disorders. MAIN OUTCOME MEASURE: The extent to which the Hepchek accurately identified the etiology of a prolonged APTT result. RESULTS: The APTT was prolonged in 25.2% of samples. The presence of heparin in the sample was confirmed by chromogenic assay or by using the Hepchek heparin-removal filter. The presence of heparin was confirmed in 12.8% of all samples and in more than 50% of all abnormal samples. The cause of the abnormal APTT was often unappreciated by the clinician. Bayesian analysis of the Hepchek's ability to diagnose heparin correctly as the cause of the abnormal APTT showed a sensitivity of 100% and specificity of 99.9%. CONCLUSION: Use of the Hepchek in the routine clinical laboratory is an efficient and rapid method of detecting heparin as a cause of isolated prolonged APTT results, and should reduce demands for unwarranted coagulation analyses and inappropriate treatment with blood products. 相似文献
155.
156.
J. de Pedro-Cuesta V. Abraira G.-X. Jiang G. Solders S. Fredrikson 《Acta neurologica Scandinavica》1996,93(2-3):175-183
Using hierarchical cluster analysis, applied to 47 cases of Guillain-Barre Syndrome (GBS) incident in South-West Stockholm (SWS) during the period from January 1973 to June 1992, we identified three major clinicoepidemiological subgroups. The first subgroup, 25.5% of the cases (26.7 ± 6.7 years), recorded a peak incidence at ages 20–29 years and presented significant differences from other subgroups, a high proportion of cases with onset at low age preceded by respiratory infection (83.3%) and with normal motor conduction velocity (50.0%). Also found, were less affected biological parameters, a rapidly progressive course and independence in gait at one month after onset. A second subgroup, 27.7% of cases, was severely affected, clinically and functionally. It consisted predominantly of young individuals (22.7 ± 11.1 years), with a high incidence (69.2% of cases) in autumn. A third subgroup, comprising 40.47; of cases, was older (61.1 ± 11.0 years) and, in general, also severely affected. The incidence of this form appeared to be invariant with time. 相似文献
157.
158.
In experiments on albino rats it was established that three administrations of indomethacin in a dose of 0.01 g/kg body weight induced a severe damage of the liver characterized by disturbances of hepatocytic membranes, bile-producing and protein-producing functions of the liver, an enhancement of lipid peroxidation, a decrease of reduced glutathione pool. Antioxidants (tocopherol acetate, essentiale, legalon, flacumin) limit manifestations of indomethacin, hepatotoxicity, as a result of which tha functional-biochemical disorders in the liver show up to a lesser degree. During the combined use of antioxidants in indomethacin-induced lesions of the liver their hepatoprotective activity increases. 相似文献
159.
S K Malhotra R Predy R Singh B L Gupta R Bhatnagar K Leeuw 《Journal of neuroscience research》1988,19(4):420-7, 472-3
A mouse monoclonal antibody (MAb 6B9, isotype IgM) was raised against autopsy tissue samples from the central nervous system (CNS) of multiple sclerosis (MS) patients. By immunofluorescence microscopy, MAb 6B9 intensely stains most or all cells in fetal rats. However, MAb 6B9 differentially stains various cell types in adult rats. Neurons, ependymal cells, and adrenal chromaffin cells are stained intensely, whereas astrocytes and oligodendrocytes are not stained. The 6B9-reactive antigen (6B9 antigen) is sensitive to periodic acid, but insensitive to treatment with protease, RNase, or hyaluronidase. Results from immunofluorescence microscopy on semithin sections and cultured neuroblastoma cells indicate that 6B9 antigen is intracellular. This is supported by immunoelectron microscopy, where labeling for 6B9 antigen appears in the cytoplasm distinct from any identifiable organelle. Further studies on 6B9 antigen should reveal its chemical nature as well as the significance of developmental changes in its distribution. 相似文献
160.
The amount of endothelial cell loss that occurs to the donor cornea during the trephination process was evaluated in 40 porcine eyes. A vital staining technique (alizarin red S and acid violet 19) was used to quantify the extent of endothelial damage and removal. Two types of corneal punches (Weck and H&I0 were used for trephination. The average amount of endothelial loss from the peripheral cornea was 7.9%, accounting for only a 3% loss of endothelial cells over the total surface area of the corneal button. a comparison of the Weck and H&I corneal punches showed no significant difference (P greater than 0.1) by Student's test for both endothelial cell damage and removal. 相似文献