全文获取类型
收费全文 | 1319篇 |
免费 | 75篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 18篇 |
妇产科学 | 37篇 |
基础医学 | 122篇 |
口腔科学 | 17篇 |
临床医学 | 107篇 |
内科学 | 356篇 |
皮肤病学 | 55篇 |
神经病学 | 75篇 |
特种医学 | 195篇 |
外科学 | 96篇 |
综合类 | 7篇 |
预防医学 | 57篇 |
眼科学 | 3篇 |
药学 | 74篇 |
中国医学 | 3篇 |
肿瘤学 | 145篇 |
出版年
2023年 | 7篇 |
2022年 | 6篇 |
2021年 | 23篇 |
2020年 | 19篇 |
2019年 | 12篇 |
2018年 | 31篇 |
2017年 | 17篇 |
2016年 | 24篇 |
2015年 | 31篇 |
2014年 | 32篇 |
2013年 | 45篇 |
2012年 | 48篇 |
2011年 | 42篇 |
2010年 | 25篇 |
2009年 | 36篇 |
2008年 | 45篇 |
2007年 | 55篇 |
2006年 | 55篇 |
2005年 | 50篇 |
2004年 | 50篇 |
2003年 | 44篇 |
2002年 | 39篇 |
2001年 | 33篇 |
2000年 | 29篇 |
1999年 | 38篇 |
1998年 | 25篇 |
1997年 | 31篇 |
1996年 | 32篇 |
1995年 | 20篇 |
1994年 | 31篇 |
1993年 | 17篇 |
1992年 | 29篇 |
1991年 | 36篇 |
1990年 | 37篇 |
1989年 | 51篇 |
1988年 | 37篇 |
1987年 | 22篇 |
1986年 | 38篇 |
1985年 | 26篇 |
1984年 | 23篇 |
1983年 | 8篇 |
1982年 | 15篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1977年 | 12篇 |
1976年 | 8篇 |
1975年 | 9篇 |
1968年 | 4篇 |
排序方式: 共有1402条查询结果,搜索用时 15 毫秒
1.
Gross cystic disease of the breast (GCD) is rarely seen after the menopause. Recent work has shown that by measuring electrolytes in the breast cyst fluid (BCF) it is possible to identify two principal classes of cyst, designated Type 1 (K+/Na+ greater than 1.5) and Type 2 (K+/Na+ less than 0.66). A smaller, intermediate class (Type 3) also appears to exist. We measured K+, Na+ and dehydroepiandrosterone sulphate (DHA-S) in 38 BCF samples aspirated from 33 women with GCD who had undergone spontaneous menopause at least 1 yr previously. Statistically significant correlations were found between DHA-S and cations (positive in relation to K+, P less than 0.001; negative in relation to Na+, P less than 0.001). The distribution of cyst types was shifted with respect to that characteristic of cases that occur at an earlier age: whereas Type 1 cysts predominate in menstruating women, Type 2 cysts proved more numerous in the post-menopausal subjects. The difference was statistically validated (P less than 0.001). The results seem to indicate a sharp reduction in high K+, high DHA-S cysts after the menopause, which may be paralleled by a decrease in the associated apocrine metaplasia. In view of the major biochemical differences between Type 1 and Type 2 cysts and of the suggested differences as regards cancer risk, classification of post-menopausal patients with GCD by cyst type is critical prior to any clinical trial or follow-up. 相似文献
2.
Hillmann JS; Mesgarzadeh M; Revesz G; Bonakdarpour A; Clancy M; Betz RR 《Radiology》1987,165(3):769-773
Proximal femoral focal deficiency, an uncommon congenital anomaly, necessitates early radiologic classification for surgical planning and treatment. Objective radiographic criteria, including femoral length index, acetabular depth index, acetabular angle index, and shape of the proximal femur were determined in 49 patients before cartilaginous ossification of the femoral capital epiphysis; final classification was based on follow-up radiographs or findings at arthrography or surgery. These parameters were analyzed to determine the accuracy and contributions of each in classification. Correct classification into one of three groups was possible in 86% of cases with use of three of the parameters: femoral length index, acetabular depth index, and shape of the proximal femur. The acetabular angle was found to contribute insignificantly to classification. Magnetic resonance imaging, used in only one case, depicted the nonossified cartilaginous femoral capital epiphysis, thus obviating the need for invasive diagnostic procedures and facilitating early classification. 相似文献
3.
S P Schinke M A Orlandi R F Schilling C Parms 《Public health reports (Washington, D.C. : 1974)》1992,107(3):323-330
Hispanic and African American adolescents are more likely than white Anglo youth to harbor misconceptions about acquired immunodeficiency syndrome (AIDS) and are also more likely to engage in intravenous drug use and sexual intercourse. This paper describes the development of an AIDS prevention curriculum that uses an interactive videodisc program to teach skills for interventions. Focus group and expert panel studies yielded suggests for intervention vignettes and scenes relevant to Hispanic and African American adolescents. The authors then developed and produced a sample curriculum, specifically designed for Hispanic youth. Content was designed to build knowledge, attitudes, and skills in handling situations where young persons are at risk for human immunodeficiency virus (HIV) infection. The feasibility of the finished pilot product was tested with adolescents and with professionals who serve ethnic and racial minority youth. Adults and Hispanic adolescent viewers rated the videodisc as enjoyable, interesting, and likely to achieve positive effects with the intended target population. Findings suggest that the interactive videodisc is a useful way to interest and help Hispanic adolescents learn ways of reducing their risk of contracting and spreading HIV infection through lifestyle practices. This developmental research in the use of interactive videodisc also provides a basis for further investigation. 相似文献
4.
The aim of the present study was to determine if data on the number and acinar distribution of apoptotic bodies (AB) in normal liver could help in the understanding of cell kinetics in the liver, and the mechanism of early ethanol-induced liver damage. Normal male Sprague-Dawley rats were studied. They had free access to Purina chow and drinking water. Ethanol-treated rats received the drug at increasing concentration in drinking water for 5 weeks. The following parameters were measured: number of AB in the lobule, topographical localization, distance from terminal hepatic veins (THV), i.e. row of hepatocytes concerned, H1 being the closest to the THV. The results show that AB are rare in the normal liver and are always observed in zone 3, next to the THV. Of 149 THV examined, 56 showed one associated AB, exceptionally two. 74% of the AB were confined to the first row of hepatocytes (H1), 21% to H2, 4% to H3, and 1% to H4. In ethanol-treated rats the mean number of AB was 2 or 3 for each THV. 42% were found in H1, 32% in H2, 15% in H3, 7% in H4, and 4% in H5. The data show that AB are not randomly dispersed in normal liver but show a preferential acinar distribution. In addition, most AB are located in the row of liver cells immediately adjacent to the THV. If apoptosis is indeed an expression of physiological cell renewal, these findings support the concept that zone 3 contains older hepatocytes.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
5.
6.
F. Sartucci G. Orlandi U. Bonuccelli D. Borghetti L. Murri C. Orsini L. Domenici V. Porciatti 《Neurological sciences》2006,26(6):395-401
Abstract Idiopathic Parkinson’s disease (IPD) patients have abnormal visual evoked potentials (VEPs) and pattern electroretinograms
(PERGs), attributed to dopaminergic transmission deficiency in visual pathway, probably the retina. VEP abnormalities are
not reported in multiple system atrophy (MSA). The aim of this study was to investigate and compare chromatic (Ch) red-green
(R-G) and blue-yellow (B-Y), and luminance yellow-black (Y-Bk) PERGs in patients with MSA and IPD. We investigated 6 MSA patients
(mean age: 62±7.4 years) not undergoing any pharmacological treatment, as well as 12 early IPD patients (mean age: 60.1±8.3
years) and 12 age-matched normal observers. ChPERGs were recorded monocularly in response to full-field equiluminant R-G,
B-Y and Y-Bk horizontal gratings. In MSA only responses to R-G stimuli showed minimal insignificant changes (slight but not
significant amplitude reduction without any significant latency delay); no significant abnormality was detected for B-Y and
luminance Y-Bk stimuli. By contrast, in IPD all responses were reduced in amplitude and delayed in latency, above all for
B-Y stimuli. Present data indicate that both chromatic and achromatic PERGs are virtually unaffected in MSA, whereas in early
IPD they are clearly impaired, suggesting different pathogenic retinal mechanisms and a useful simple tool for distinguishing
MSA from IPD. 相似文献
7.
8.
Enumeration of S-phase cells in normal rat liver by immunohistochemistry using bromodeoxyuridine-antibromodeoxyuridine system 总被引:2,自引:0,他引:2
Dr. A. M. Jezequel MD F. Paolucci MD A. Benedetti MD R. Mancini MD F. Orlandi MD 《Digestive diseases and sciences》1991,36(4):482-484
The visualization of incorporation sites of the thymidine analog bromodeoxyuridine (BrdU) into DNA, detected by immunocytochemistry, has been proposed as an index of the percentage of S-phase cells in a variety of tissues and as an easy, less expensive alternative to autoradiography. This technique has not yet been applied to the study of physiological cell renewal in the normal liver. In the present study, results obtained with this method in the liver of normal young adult rats is reported. BrdU was administered in vivo and subsequent incorporation was detected by the PAP technique using monoclonal anti-BrdU antibodies. The nuclei exhibiting a positive reaction within the liver were few and accounted for about 0.45% of all hepatocytes. Positive cells were located preferentially in zone 1, which contained 82.7% of the labeled cells. Zone 2 contained 15.4%, while only 1.9% of the labeled cells were found in zone 3. Positive-staining Kupffer cell nuclei were rare (about 0.5% of all Kupffer cells) and were distributed randomly in the hepatic lobule. These findings provide quantitative data about hepatocyte renewal in the normal liver in the absence of a growth stimulus. The simplicity and the reproducibility of this technique suggests that further application of this method in situations assessing hepatic regeneration are indicated. 相似文献
9.
10.
M A Orlandi 《Women & health》1986,11(3-4):237-251
Men and women have traditionally consumed cigarettes very differently, demonstrating widely varying patterns of prevalence during the past eight decades. For example, though the prevalence of smoking among men increased dramatically soon after the turn of the century, an analogous though less dramatic increase among women was not observed for another 25-30 years. Similarly, when a dramatic decrease in smoking prevalence among men was observed following the 1964 Surgeon General's Report, a comparable decrease among women was not seen until 15 years later. Such differences in smoking patterns have led to the widespread belief that giving up smoking is more difficult for women than it is for men. This paper reviews various studies which address this issue and suggests areas in which further research is needed. 相似文献