全文获取类型
收费全文 | 1601632篇 |
免费 | 131525篇 |
国内免费 | 2582篇 |
专业分类
耳鼻咽喉 | 21646篇 |
儿科学 | 52928篇 |
妇产科学 | 46225篇 |
基础医学 | 227766篇 |
口腔科学 | 47199篇 |
临床医学 | 140902篇 |
内科学 | 314774篇 |
皮肤病学 | 34092篇 |
神经病学 | 130101篇 |
特种医学 | 64723篇 |
外国民族医学 | 474篇 |
外科学 | 243792篇 |
综合类 | 39713篇 |
现状与发展 | 3篇 |
一般理论 | 544篇 |
预防医学 | 122856篇 |
眼科学 | 36470篇 |
药学 | 121254篇 |
3篇 | |
中国医学 | 2974篇 |
肿瘤学 | 87300篇 |
出版年
2018年 | 14765篇 |
2016年 | 12898篇 |
2015年 | 15026篇 |
2014年 | 20648篇 |
2013年 | 31349篇 |
2012年 | 42547篇 |
2011年 | 44748篇 |
2010年 | 26335篇 |
2009年 | 25302篇 |
2008年 | 42995篇 |
2007年 | 45237篇 |
2006年 | 46047篇 |
2005年 | 44674篇 |
2004年 | 44089篇 |
2003年 | 42181篇 |
2002年 | 41290篇 |
2001年 | 75682篇 |
2000年 | 78325篇 |
1999年 | 66387篇 |
1998年 | 17731篇 |
1997年 | 16334篇 |
1996年 | 16316篇 |
1995年 | 16019篇 |
1994年 | 15071篇 |
1993年 | 14217篇 |
1992年 | 55432篇 |
1991年 | 53778篇 |
1990年 | 52562篇 |
1989年 | 50833篇 |
1988年 | 47226篇 |
1987年 | 46561篇 |
1986年 | 44284篇 |
1985年 | 42843篇 |
1984年 | 32033篇 |
1983年 | 27566篇 |
1982年 | 16144篇 |
1981年 | 14436篇 |
1980年 | 13564篇 |
1979年 | 30460篇 |
1978年 | 21065篇 |
1977年 | 17765篇 |
1976年 | 16694篇 |
1975年 | 17574篇 |
1974年 | 21486篇 |
1973年 | 20672篇 |
1972年 | 18853篇 |
1971年 | 17770篇 |
1970年 | 16289篇 |
1969年 | 15268篇 |
1968年 | 13949篇 |
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
111.
F. M. RAAPHORST R. LANGLOIS VAN DEN BERGH J. L. M. WAAIJER J. M. VOSSEN & M. J. D. VAN TOL 《Scandinavian journal of immunology》1997,46(3):292-297
Fetal B lymphocytes in mice and humans use a limited number of the available VH gene segments. Mouse fetal B cells primarily utilize 3' VH elements, suggesting that the localization of these elements determines their rearrangement frequency. The previously reported non-random usage of human VH genes has been more difficult to explain. In this study the authors analysed the expression of the most proximal 3' human VH element (VH 6) using a monoclonal antibody (JE-6). VH 6 expression was assessed in various B cell differentiation stages from fetal liver, bone marrow and spleen at 12–20 weeks of gestation. The authors demonstrate that the level of VH 6 expression does not exceed a stochastic usage frequency. This suggests that the localization of VH 6 does not significantly promote its expression during human fetal life, and that other factors must affect the usage of VH genes during human fetal development. 相似文献
112.
113.
Three hundred and twenty samples of subgingival plaque were obtained from 80 caucasian girls, ranging from 10 to 13 years of age. The samples were analyzed to verify the influence of age upon colonization of the gingival sulcus by microorganisms potentially pathogenic to the periodontal tissues. The gingival and plaque status were evaluated through the gingival index (GI) and plaque index (PlI) and the microflora was assessed by the enzymatic method benzoyl-arginine-naphthylamide (BANA). The results of the BANA test were positive for 62.50% of the tested individuals and 40% of the examined sites. The influence of age was statistically significant on BANA reactivity, and the number of positive sites was greater at 11 (57.5%) than at 12 years (28.8%). 相似文献
114.
115.
116.
L R Bergman 《Acta paediatrica Scandinavica》1991,80(12):1250-1252
117.
This study examined electromyogram (EMG) and skin conductance level (SCL) as mediators of neuropsychological test performance of alcoholics. Alcoholics and controls with high EMG performed less well than low EMG subjects on 12 measures of neuropsychological performance. For SCL, the alcoholics and controls in the Low Group did not differ from those in the High Group on any measure. Analyses that used information intake (Low EMG and High SCL) and rejection (High EMG and Low SCL) information postures (IPs) demonstrated that the intake group outperformed the rejection group on 10 neuropsychological measures. Subjects with intake IPs reported more stimulation, concentration, and interest during the tasks than did subjects with rejection IPs. Results suggest that IPs can be used to identify alcoholics with neuropsychological deficits. 相似文献
118.
R G Jones J W Bass M E Weisse J M Vincent 《The Pediatric infectious disease journal》1991,10(8):557-559
We tested the urine of 30 infants 6 weeks to 7 months of age after they received standard 10-micrograms (0.5-ml) doses of HbOC (HibTITER) Haemophilus influenzae b (Hib) conjugate vaccine for the presence of Hib antigenuria using a commercially available latex particle agglutination assay (Directigen). Urines were collected within 1 hour, from 1 to 3 hours, at 24 hours and at 3, 6 and 9 days after vaccine administration and reactions were quantitated from 0 to 3+. In contrast to previous studies in older children which showed little or no antigenuria following HbOC vaccination, our study shows that in infants intense Hib antigenuria is evident within 2 to 3 hours and persists 3 days after vaccine administration and that less intense antigenuria may be detected in some infants for several days. With efficacious vaccines now being used in 2- to 6-month-old infants, invasive Hib disease may soon be limited to infants of this age just before their seroconversion. It should be recognized that antigenuria occurs for several days after vaccination with Hib conjugate vaccines and that it could be erroneously interpreted as evidence of invasive Hib infection. 相似文献
119.
Analysis of accident logs in child day care centers indicates that biting is common, especially among toddlers 13 to 30 months of age. Children of this age often lack appropriate verbal skills and resort to aggressive means to achieve their goals. Still awkward in gross-motor skills, toddlers can also suffer self-bites following accidental falls. According to medical reports, human bites sometimes are more virulent than animal bites and can cause severe trauma. Although the AIDS virus has been cultured from saliva, transmission from saliva alone has not been documented. Bite injuries in day care, however, usually are minor and can be treated by washing, applying cold compresses, and comforting the child. Suggested methods to diminish the frequency of biting in day care include physical changes within the room, behavior modification, and other classroom management techniques. 相似文献
120.
Lipid metabolism and hyperandrogenism. 总被引:1,自引:0,他引:1
R A Wild 《Clinical obstetrics and gynecology》1991,34(4):864-871
Hyperandrogenism and lipid metabolism were shown to be related intimately. Any discussion of the nature of their relationship must include other clinical and metabolic variables such as hyperinsulinemia and UBO. Despite the many correlations among each of these factors, the appropriate sequence in the pathogenesis of these conditions has not been defined. Do conditions that result in insulin resistance (e.g., genetic defects, insulin receptor antibodies, and obesity) also lead to the development of hyperandrogenemia by direct or indirect ovarian stimulation by insulin? Does hyperandrogenism of ovarian or adrenal origin cause abnormal upper body fat distribution, in turn leading to lipid abnormalities and insulin resistance? Regardless of the issue of mechanism of causality, women with hyperandrogenism are thought to be at greater risk for cardiovascular morbidity and mortality than their normoandrogenic counterparts. These women often are obese, hypertensive, and sedentary; ingest diets high in saturated fats; and have glucose intolerance and/or insulin resistance. All these abnormalities are well known independent risk factors for the development of lipid abnormalities and cardiovascular disease. Whether hyperandrogenism is a secondary consequence of any of these or whether it is an independent contributor to lipid aberrations requires future study. Treatment strategies for hyperandrogenic women, however, should not only be directed toward alleviation of the cosmetic problem of hirsutism but also toward the prevention and treatment of cardiovascular morbidity using modalities aimed at eradicating hyperinsulinemia, hypertension, and dyslipidemia. These modalities should include modifications in diet, exercise, and weight in addition to pharmacologic and/or surgical manipulation. Weight reduction will reduce many cardiovascular risk factors. Obesity is easier to target because of the many risk factors that result in it.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献