全文获取类型
收费全文 | 745篇 |
免费 | 39篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 68篇 |
儿科学 | 15篇 |
妇产科学 | 14篇 |
基础医学 | 51篇 |
口腔科学 | 18篇 |
临床医学 | 137篇 |
内科学 | 156篇 |
皮肤病学 | 8篇 |
神经病学 | 78篇 |
特种医学 | 49篇 |
外科学 | 91篇 |
综合类 | 6篇 |
预防医学 | 63篇 |
眼科学 | 3篇 |
药学 | 26篇 |
肿瘤学 | 9篇 |
出版年
2021年 | 9篇 |
2019年 | 7篇 |
2018年 | 12篇 |
2017年 | 9篇 |
2016年 | 7篇 |
2015年 | 11篇 |
2014年 | 17篇 |
2013年 | 32篇 |
2012年 | 70篇 |
2011年 | 39篇 |
2010年 | 25篇 |
2009年 | 12篇 |
2008年 | 40篇 |
2007年 | 31篇 |
2006年 | 32篇 |
2005年 | 34篇 |
2004年 | 27篇 |
2003年 | 29篇 |
2002年 | 35篇 |
2001年 | 30篇 |
2000年 | 32篇 |
1999年 | 26篇 |
1998年 | 17篇 |
1997年 | 8篇 |
1996年 | 15篇 |
1995年 | 10篇 |
1994年 | 13篇 |
1993年 | 9篇 |
1992年 | 15篇 |
1991年 | 18篇 |
1990年 | 12篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 10篇 |
1976年 | 4篇 |
1974年 | 4篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1969年 | 4篇 |
1966年 | 2篇 |
1940年 | 2篇 |
排序方式: 共有792条查询结果,搜索用时 31 毫秒
1.
TG Berger F Kiesewetter C Maczek N Bauer M Lueftl G Schuler M Simon Jr 《Journal of the European Academy of Dermatology and Venereology》2006,20(2):178-183
Vitiligo and psoriasis are both common skin disorders. However, psoriasis strictly confined to pre-existing vitiligo areas is rare and suggests a causal relationship. We report here on two patients with a strict anatomical colocalization of vitiligo and psoriasis. The histopathological examinations showed typical changes for both diseases together with a dense infiltrate of CD4+ and CD8+ T cells. By immunohistochemistry, intracytoplasmatic granzyme B and tumour necrosis factor alpha (TNF-alpha) were detected within the T-cell population, suggesting the functional activity of these cells and the creation of a local T helper 1 (Th1)-cytokine milieu. Additionally, in one patient we could identify anti-melanocytic T cells by tetramer staining and enzyme-linked immunospot (ELISPOT) analysis. These skin-infiltrating lymphocytes might trigger, by the local production of Th-1 cytokines such as TNF-alpha and interferon-gamma (IFN-gamma), the eruption of psoriatic plaques in patients with a genetic predisposition for psoriasis. 相似文献
2.
3.
4.
5.
Medial border of the perirenal space: CT and anatomic correlation 总被引:11,自引:0,他引:11
6.
J S Appelbaum R P Roos E F Salazar-Grueso A Buchman S Iannaccone R Glantz T Siddique R Maselli 《Neurology》1992,42(8):1488-1492
Although there are varied inheritance patterns in motor neuron disease (MND), the phenotype of MND is reported to be constant within these families, ie, cases of amyotrophic lateral sclerosis or primary lateral sclerosis do not occur in pedigrees with cases of spinal muscular atrophy. We describe four pedigrees whose members diverged in the phenotype of MND expressed. The intrafamilial variation of phenotype suggests a similar pathogenesis for some of the varied types of familial MND and the need for careful inquiry of family history in all patients with MND. 相似文献
7.
Circannual variation in lymphocyte subsets, revisited 总被引:2,自引:0,他引:2
BACKGROUND: Circadian and circannual variations in lymphocyte subsets, especially CD8+ T-lymphocytes, have been reported. This study focuses on CD4+ T-lymphocyte seasonal variation over a 6-year 8-month period. STUDY DESIGN AND METHODS: Lymphocyte subsets were quantitated monthly for four healthy individuals from 1986 through 1992 as part of a flow cytometry quality-control program. RESULTS: In general, there were no significant seasonal changes in the total number of white cells or in total lymphocyte counts. The absolute numbers of CD4+ T-lymphocytes were lowest in summer when the CD8+ T-lymphocytes were highest. Mean CD4+ T-lymphocyte counts were 846, 967, 618, and 695 per microL for Subjects 1 through 4, respectively, in winter and 432, 670, 355, and 766 per microL, respectively, in summer. Two healthy subjects had CD4+ T-lymphocyte counts lower than 300 per microL on one or more occasions during the study period. In three of the four subjects, the percentage of B-lymphocytes in winter was almost double that in summer. In one of the four subjects, no circannual rhythm was observed in these lymphocyte subpopulations. CONCLUSION: The seasonal variation in CD4+ T- lymphocyte counts demonstrated in three healthy individuals over almost 7 years is again of interest in light of renewed consideration of using surrogate tests, such as CD4+ T-lymphocyte counts, to screen for AIDS- like diseases that may be in the blood supply. 相似文献
8.
A rapid microagglutination test for the diagnosis of Legionella pneumophila (serogroup 1) infection 总被引:4,自引:3,他引:4 下载免费PDF全文
A rapid microagglutination test has been developed which can be performed in 30 minutes. Ninety-seven percent of 96 patients diagnosed as having Legionella pneumophila (serogroup 1) infection by indirect immunofluorescence were also detected by the rapid microagglutination test. 相似文献
9.
Regulation of DAF-2 receptor signaling by human insulin and ins-1, a member of the unusually large and diverse C. elegans insulin gene family 下载免费PDF全文
Pierce SB Costa M Wisotzkey R Devadhar S Homburger SA Buchman AR Ferguson KC Heller J Platt DM Pasquinelli AA Liu LX Doberstein SK Ruvkun G 《Genes & development》2001,15(6):672-686
The activity of the DAF-2 insulin-like receptor is required for Caenorhabditis elegans reproductive growth and normal adult life span. Informatic analysis identified 37 C. elegans genes predicted to encode insulin-like peptides. Many of these genes are divergent insulin superfamily members, and many are clustered, indicating recent diversification of the family. The ins genes are primarily expressed in neurons, including sensory neurons, a subset of which are required for reproductive development. Structural predictions and likely C-peptide cleavage sites typical of mammalian insulins suggest that ins-1 is most closely related to insulin. Overexpression of ins-1, or expression of human insulin under the control of ins-1 regulatory sequences, causes partially penetrant arrest at the dauer stage and enhances dauer arrest in weak daf-2 mutants, suggesting that INS-1 and human insulin antagonize DAF-2 insulin-like signaling. A deletion of the ins-1 coding region does not enhance or suppress dauer arrest, indicating a functional redundancy among the 37 ins genes. Of five other ins genes tested, the only other one bearing a predicted C peptide also antagonizes daf-2 signaling, whereas four ins genes without a C peptide do not, indicating functional diversity within the ins family. 相似文献
10.
Studies on the origin of redox enzymes in seminal plasma and their relationship with results of in-vitro fertilization 总被引:3,自引:0,他引:3
Yeung CH; Cooper TG; De Geyter M; De Geyter C; Rolf C; Kamischke A; Nieschlag E 《Molecular human reproduction》1998,4(9):835-839
Glutathione (GSH), GSH peroxidase (GPX), GSH reductase (GRD), superoxide
dismutase (SOD) and catalase-like enzyme activity were quantified in
seminal plasma from normozoospermic patients, men with known distal ductal
occlusion, proven fathers and male partners of couples receiving in-vitro
fertilization (IVF) treatment for both male and female causes. Glutathione
was non-detectable (< 2.5 microM) in seminal plasma. None of the enzyme
activities per unit volume were lower in semen from vasectomized men,
suggesting that they did not originate substantially from the testis or
epididymis. The strongest relationships between enzyme activities and
accessory gland markers were between zinc and GRD (r = 0.678), SOD (r =
0.602) and GPX (r = 0.548), suggesting a largely prostatic origin of these
enzymes. Only weak relationships between accessory gland markers and
catalase-like activity suggested a multi-glandular source of this enzyme.
There was no relationship between the activity of any of the enzymes in the
IVF patients with their fertilization rates in vitro or the establishment
of pregnancy after IVF. Nor was there any correlation of enzyme activity
with the morphology and percentage of motile spermatozoa in semen or with
the percentage motility of spermatozoa immediately after swim-up or after
overnight incubation. These findings suggest that the protective enzymes in
the seminal plasma are contributed largely by the prostate and little by
the epididymis, and that in most cases of IVF, they have no major influence
on the outcome.
相似文献