全文获取类型
收费全文 | 2436951篇 |
免费 | 195870篇 |
国内免费 | 8225篇 |
专业分类
耳鼻咽喉 | 32017篇 |
儿科学 | 80121篇 |
妇产科学 | 68295篇 |
基础医学 | 339997篇 |
口腔科学 | 66679篇 |
临床医学 | 221026篇 |
内科学 | 490191篇 |
皮肤病学 | 57859篇 |
神经病学 | 202047篇 |
特种医学 | 96138篇 |
外国民族医学 | 708篇 |
外科学 | 370192篇 |
综合类 | 58107篇 |
现状与发展 | 4篇 |
一般理论 | 831篇 |
预防医学 | 195521篇 |
眼科学 | 54028篇 |
药学 | 171030篇 |
6篇 | |
中国医学 | 5011篇 |
肿瘤学 | 131238篇 |
出版年
2018年 | 26531篇 |
2017年 | 20542篇 |
2016年 | 23874篇 |
2015年 | 26709篇 |
2014年 | 37663篇 |
2013年 | 56321篇 |
2012年 | 72568篇 |
2011年 | 77706篇 |
2010年 | 47136篇 |
2009年 | 45427篇 |
2008年 | 72161篇 |
2007年 | 76539篇 |
2006年 | 77788篇 |
2005年 | 75471篇 |
2004年 | 72116篇 |
2003年 | 69361篇 |
2002年 | 66407篇 |
2001年 | 118706篇 |
2000年 | 121707篇 |
1999年 | 101375篇 |
1998年 | 29879篇 |
1997年 | 26901篇 |
1996年 | 27660篇 |
1995年 | 27053篇 |
1994年 | 24904篇 |
1993年 | 23409篇 |
1992年 | 80315篇 |
1991年 | 77533篇 |
1990年 | 74468篇 |
1989年 | 70937篇 |
1988年 | 65503篇 |
1987年 | 64191篇 |
1986年 | 60308篇 |
1985年 | 57963篇 |
1984年 | 44202篇 |
1983年 | 37333篇 |
1982年 | 23134篇 |
1981年 | 20680篇 |
1980年 | 19268篇 |
1979年 | 39585篇 |
1978年 | 28339篇 |
1977年 | 23756篇 |
1976年 | 22036篇 |
1975年 | 22823篇 |
1974年 | 27123篇 |
1973年 | 26103篇 |
1972年 | 24369篇 |
1971年 | 22324篇 |
1970年 | 20840篇 |
1969年 | 19395篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The use of bacterins is one of the primary methods in the control of leptospirosis in domestic animals, especially cattle, swine, and dogs. Bacterins have been made using chemically treated or heat-inactivated organisms. Many of the initial studies indicated that the bacterins gave complete protection, whereas later reports found that some inactivation methods resulted in bacterins that protect against death but not against kidney infection and renal shedding. This raised the possibility that some of the antigens had been altered. To investigate this possibility, we heat or chemically treated Leptospira interrogans serovar icterohaemorrhagiae CF-1, L. interrogans serovar canicola Moulton, L. interrogans serovar grippotyphosa SC4397, L. interrogans serovar hardjo Hardjoprajitno, and L. interrogans serovar pomona MLS. Temperatures used to determine alterations in antigens were 50, 56, 80, 100, and 121 degrees C. The chemicals used were formaldehyde, phenol, and thimerosal. Analysis was done using Laemmli gels and Western blots. We found that heating at 50 or 56 degrees C had the smallest effect on antigens, whereas heating at 80 or 100 degrees C caused the appearance of high-molecular-weight bands on Western blots. Heating at 121 degrees C caused almost all the bands to disappear, in both the stained gel and the Western blot. Both phenol and Formalin treatment altered proteins, whereas thimerosal treatment appeared to have little effect compared with heating at 50 degrees C. 相似文献
992.
993.
Thomas J Birk Rodger D MacArthur Lynn M Lipton Sheldon D Levine 《The Journal of the Association of Nurses in AIDS Care》2002,13(6):20-24
The purpose of this study was to determine whether blood lipid and lipoprotein concentrations varied in 5 men with advanced HIV-1 infection after 12 months of aerobic exercise training. Prior to exercise, the mean baseline cholesterol and high-density lipoprotein cholesterol (HDL-C) serum concentration were each lower, and mean baseline triglyceride concentration was higher compared to a healthy population norm. Consistent exercise training for 12 months failed to significantly (p > .05) alter cholesterol or HDL-C. Triglyceride concentration was significantly (p < .05) elevated above baseline (63 mg/dL) regardless of exercise compliance. The results suggest that long-term exercise training cannot correct lipid profile abnormality, particularly hypertriglyceridemia, common to individuals with advanced HIV-1 infection. 相似文献
994.
995.
A Messineo R M Filler B Bahoric C Smith A Bahoric 《Journal of pediatric surgery》1991,26(11):1296-1300
A major problem in tracheal transplantation is the restoration of an adequate vascular supply to the transplanted trachea. In 12 piglets, a segment (6 rings) of thoracic trachea was removed and the excised segment was then sutured back in place. In 9 animals (group A), a vascularized omental flap was wrapped around the autotransplanted trachea. In the other 3 pigs (group B), the omentum was not used. Eight of 9 group A pigs were killed, 1 or 2 months later, having had no signs of airway obstruction; the 9th pig was killed after 14 days because of airway obstruction. The 3 pigs in group B were killed after 11 to 13 days because of progressive respiratory obstruction. In the 8 asymptomatic pigs in group A, the omental flap was viable and tracheal growth was normal with no differences in diameter between normal and autotransplanted trachea. Histologically intact cartilage was lined with respiratory epithelium. In the one group A pig who was killed early, the omental flap was necrotic. In this pig and in the 3 group B animals, extensive tracheal necrosis and nonviable cartilage were observed. These findings indicate that in the pig, a 6-ring segment of trachea can be transplanted with vascularization provided by an omental flap. 相似文献
996.
Changing attentional demands in left hemispatial neglect. 总被引:1,自引:0,他引:1
R F Kaplan M Verfaellie M E Meadows L R Caplan M S Pessin L D DeWitt 《Archives of neurology》1991,48(12):1263-1266
Seven variations of a letter cancellation test were used to examine how varying attentional demands affect hemispatial neglect in patients with right hemisphere lesions. While the 14 targets always remained in the same location, the number of distractors (zero, nine, 28, or 82) as well as their complexity (one letter or nine different letters) were varied. The percentage of targets canceled in the left hemispace was linearly related to the number of distractors. There were no differences between the complexity conditions. In a second study, the same 14 targets were presented but the distractors (zero, 14, or 41) were all placed on the right. Increasing the number of distractors on the right increased neglect on both sides of the space. Taken together, these results suggest that, while the limited attentional resources of the left hemisphere are biased toward the right hemispace, the absence of contralateral attentional demands allows these resources to be directed ipsilaterally. 相似文献
997.
998.
K W Anquist S Panchanathan P C Rowe R G Peterson A Sirnick 《Canadian Medical Association journal》1991,145(8):965-968
OBJECTIVE: To determine whether the use of dimenhydrinate was associated with delay in the diagnosis and management of treatable illnesses or with direct adverse effects in children with vomiting presenting to an emergency department. DESIGN: Questionnaire survey and review of drug reaction and telephone inquiry records. SETTING: The emergency department of a tertiary care children's hospital and a provincial poison information centre. PATIENTS: The parents of 148 children who presented with vomiting completed the questionnaire. The database at the poison information centre included 474 reports of adverse drug reactions over an 8-year period and 105 reports of telephone inquiries over a 4-year period. MAIN RESULTS: Twenty-one (14%) of 148 children had received dimenhydrinate before arrival at the emergency department. The patients who had received dimenhydrinate were more likely than the others to present more than 12 hours after the onset of vomiting (14 [67%] of 21 v. 43 [34%] of 127, p less than 0.01). The discharge diagnoses for those who had received dimenhydrinate included asthma, pelvic inflammatory disease and urinary tract infection. No clinically important direct adverse reactions to dimenhydrinate were documented. CONCLUSIONS: The use of dimenhydrinate in children with vomiting is associated with a risk of delay in the diagnosis of treatable medical conditions. 相似文献
999.
1000.
The precision and accuracy of manual reticulocyte counts using the Miller disc reticle, other ruled reticle and no reticle are compared with the reticulocyte results from the automated Hematrak 590 instrument. Two slides of each of 50 patient blood specimens were sent to the hematology laboratories of each of six participating hospitals. In addition to between-method comparison (precision), the manual method results using the three different counting techniques were each compared with the Hematrak results to determine if there were significant differences in reported results (accuracy). Statistical analysis revealed that the Miller disc method was the most precise and accurate manual method as compared with the Hematrak. Methods without a Miller disc reported significantly higher reticulocyte counts. Imprecision was also higher among non-Miller manual methods. By using the Miller disc, the accuracy and precision of manual methods may be increased to that of the automated Hematrak method. 相似文献