全文获取类型
收费全文 | 2144830篇 |
免费 | 151029篇 |
国内免费 | 3972篇 |
专业分类
耳鼻咽喉 | 31514篇 |
儿科学 | 68015篇 |
妇产科学 | 60447篇 |
基础医学 | 303181篇 |
口腔科学 | 62931篇 |
临床医学 | 187923篇 |
内科学 | 409791篇 |
皮肤病学 | 48775篇 |
神经病学 | 168380篇 |
特种医学 | 84346篇 |
外国民族医学 | 595篇 |
外科学 | 327447篇 |
综合类 | 48592篇 |
现状与发展 | 7篇 |
一般理论 | 677篇 |
预防医学 | 153207篇 |
眼科学 | 51422篇 |
药学 | 165687篇 |
10篇 | |
中国医学 | 5062篇 |
肿瘤学 | 121822篇 |
出版年
2018年 | 20754篇 |
2016年 | 18584篇 |
2015年 | 20731篇 |
2014年 | 28817篇 |
2013年 | 43157篇 |
2012年 | 57638篇 |
2011年 | 61082篇 |
2010年 | 36104篇 |
2009年 | 34429篇 |
2008年 | 57533篇 |
2007年 | 62319篇 |
2006年 | 63147篇 |
2005年 | 60579篇 |
2004年 | 58592篇 |
2003年 | 56414篇 |
2002年 | 55066篇 |
2001年 | 104508篇 |
2000年 | 107293篇 |
1999年 | 90253篇 |
1998年 | 24076篇 |
1997年 | 21637篇 |
1996年 | 21141篇 |
1995年 | 19871篇 |
1994年 | 18440篇 |
1993年 | 17345篇 |
1992年 | 69486篇 |
1991年 | 67134篇 |
1990年 | 65984篇 |
1989年 | 64036篇 |
1988年 | 59050篇 |
1987年 | 57915篇 |
1986年 | 55217篇 |
1985年 | 52332篇 |
1984年 | 38914篇 |
1983年 | 33056篇 |
1982年 | 19304篇 |
1981年 | 17403篇 |
1979年 | 36698篇 |
1978年 | 25787篇 |
1977年 | 22628篇 |
1976年 | 20325篇 |
1975年 | 23065篇 |
1974年 | 27240篇 |
1973年 | 26566篇 |
1972年 | 25290篇 |
1971年 | 23678篇 |
1970年 | 22197篇 |
1969年 | 21354篇 |
1968年 | 19697篇 |
1967年 | 17648篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Synthesis of Estradiol Haptens Two estradiol haptens, 4-(3β,17β-dihydroxyestran-7α-yl)butanoic acid ( 9 ) and 7α-(4-aminobutyl)-3β,17β-estradiols ( 13 ), were prepared from 19-nortestosterone by partial synthesis. The binding activity for the cytosol estrogen receptor was determined by competition against [3H]-estradiol; at a concentration of 2×10?7mol/l, compound 9 displaces 50% of [3H]-estradiol. Attached to AH-Sepharose 4B compound 9 allows the cytosol estrogen receptor from calf uterus to be concentrated 1800-fold by affinity chromatography. 相似文献
992.
993.
994.
Haemophilus influenzae vaccine containing polyribosyl ribitol phosphate (PRP) or PRP covalently linked to diphtheria toxoid (PRP-D) was given to 94 healthy infants 17 to 22 months of age at the same time, but not at the same site, as a diphtheria-tetanus-pertussis booster. Systemic reactions were similar in the two vaccine groups and resembled those expected with the diphtheria-tetanus-pertussis injection alone. Six (13%) and seven (14%) of the PRP and PRP-D recipients, respectively, had minor local reactions to the Haemophilus vaccine. Among the 77 children who were not already naturally immune (ie, anti-PRP antibody concentration of less than or equal to 0.15 micrograms of protein per milliliter) before vaccination, PRP-D was significantly more effective than PRP in inducing protective levels of antibody. Only 15 (43%) of the 35 nonimmune PRP recipients achieved a concentration of greater than or equal to 0.15 microgram/mL and only seven (20%) reached a concentration greater than or equal to 1.0 micrograms/mL following vaccination. In contrast, 34 (81%) of the 42 nonimmune recipients of PRP-D had a concentration of greater than or equal to 0.15 microgram/mL following vaccine and 32 (62%) had a concentration of greater than or equal to 1.0 micrograms/mL (P less than or equal to .001). These results suggest that more than one-half of nonimmune 18-month-old infants will not respond to PRP with protective levels of antibody. In light of the current data, recommendation for revaccination at 24 months of age for those immunized at any younger age is appropriate. 相似文献
995.
996.
The purpose of this study was to evaluate a new fluorescence polarization immunoassay, TDx, for digitoxin by comparing the results of this assay with those of a radioimmunoassay (RIA). Thirty-three serum samples were obtained from 15 patients during, and for 4 weeks after, a 4-week course of digitoxin therapy. Each sample was separated by centrifugation, coded, and frozen until analysis. At the time of analysis, each sample was divided and analyzed simultaneously by TDx and RIA. Nine samples yielded results less than 2 ng/ml (limit of assay sensitivity) by one or both methods and were excluded from further data analysis. Linear regression analysis of the results of the remaining 24 paired samples (x = TDx, y = RIA) revealed a strong correlation coefficient of r2 = 0.95, slope = 0.95, and a y intercept of -0.99 (y = -0.99 + 0.95x). Additionally, the TDx results were lower than the RIA values in only five of 33 paired samples; and these occurred in four patients who had a significantly lower mean estimated creatinine clearance than that of the other 11 patients (39.0 +/- 9.1 ml/min/1.73 m2 vs. 63.3 +/- 11.8 ml/min/1.73 m2, p less than 0.01). The TDx system is a comparable alternative to the RIA method, but differences in specificity and sensitivity may exist and should be evaluated more thoroughly. 相似文献
997.
998.
999.
H R Olivier 《Southern medical journal》1987,80(12):1498-1504
The hospital now known as the Gillis W. Long Hansen's Disease Center is the only hospital in the United States solely treating Hansen's disease (leprosy). From the time of its establishment in 1894 until 1923, the psychiatric patients presented treatment and management problems that remained unaddressed. Since 1923, however, psychiatric consultants have provided care and treatment for this segment of the Carville population. This paper presents the findings of three of these consultants for the period 1923 to 1985, and outlines similarities and differences in the diagnoses, treatments, and disposition of patients, as well as indications for future investigations. 相似文献
1000.
Teenage pregnancy is a well-documented problem in the United States, with approximately 890,000 teenage pregnancies occurring each year. Although teen pregnancy rates have declined since 1991, rates remain higher than the mid-1970s and are fourfold those of European countries. Substantial morbidity and social problems result from these pregnancies, affecting the mother, her children, other family members, and society. Multiple educational approaches have been used, with few demonstrating significant reductions in teen pregnancy. School-based programs have been diverse and multifaceted. Recently, programs with a comprehensive approach have shown potential for success. In this article, characteristics and elements of promising school-based programs are identified and discussed. It is imperative that school nurses play an active role in developing and implementing prevention programs that incorporate rigorous evaluation. As health educators, school nurses are in a prime position to implement and evaluate the effectiveness of teen pregnancy prevention programs. 相似文献