全文获取类型
收费全文 | 432篇 |
免费 | 26篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 21篇 |
妇产科学 | 5篇 |
基础医学 | 51篇 |
口腔科学 | 12篇 |
临床医学 | 53篇 |
内科学 | 80篇 |
皮肤病学 | 18篇 |
神经病学 | 15篇 |
特种医学 | 36篇 |
外科学 | 39篇 |
综合类 | 17篇 |
预防医学 | 43篇 |
眼科学 | 6篇 |
药学 | 59篇 |
肿瘤学 | 7篇 |
出版年
2021年 | 3篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2017年 | 7篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 14篇 |
2013年 | 25篇 |
2012年 | 17篇 |
2011年 | 18篇 |
2010年 | 19篇 |
2009年 | 26篇 |
2008年 | 21篇 |
2007年 | 19篇 |
2006年 | 20篇 |
2005年 | 27篇 |
2004年 | 14篇 |
2003年 | 8篇 |
2002年 | 13篇 |
2001年 | 6篇 |
2000年 | 13篇 |
1999年 | 7篇 |
1998年 | 18篇 |
1997年 | 20篇 |
1996年 | 20篇 |
1995年 | 18篇 |
1994年 | 11篇 |
1993年 | 14篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 9篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有471条查询结果,搜索用时 31 毫秒
61.
Aggregated IgE mimic interleukin-3-induced histamine synthesis by murine hematopoietic progenitors 总被引:1,自引:0,他引:1
Salachas F; Schneider E; Lemoine FM; Lebel B; Daeron M; Navarro S; Ziltener H; Dy M 《Blood》1994,84(4):1098-1107
Similar to interleukin-3 (IL-3), IgE acts on murine bone marrow cells by inducing histamine production. This effect does not result from degranulation of histamine-containing cells, but from histamine synthesis, as assessed by the following findings. (1) The histamine content of freshly isolated bone marrow cells is too low to account for the increase in extracellular histamine levels. (2) Neither IL-3 nor IgE induced histamine production in the presence of the specific inhibitor of histidine decarboxylase (HDC), the histamine-forming enzyme. (3) Both the enzymatic activity and the mRNA expression of HDC were enhanced in response to IL-3 or IgE. Artificial aggregation or formation of IgE immune complexes augmented ther effect on histamine synthesis, indicating that the aggregated form is responsible for this biologic activity. Yet, it is apparently not mediated by Fc epsilon RI because their cross-linkage by dinitrophenyl bovine serum albumin after presensitization with IgE did not induce histamine production by hematopoietic progenitors. Among other aggregated isotypes tested, only IgG2a and, to a lesser extent, IgG1 had a consistent but lower effect, whereas IgM and IgA were completely inactive. The target cells of IL-3 and IgE in terms of histamine synthesis do not belong to mature bone marrow populations, especially mast cells. They copurify with hematopoietic progenitors in the low-density layers of a discontinuous Ficoll gradient where they represent around 5% of the cells, as determined by in situ hybridization. This percentage remained the same, regardless of whether the cells were stimulated by IgE or IL-3 alone or by a combination of both, suggesting a common responder cell. In accordance with this notion, histamine-producing cells could not be distinguished from each other on the basis of density, size and internal structure, or rhodamine (Rh) retention. Finally, the effect of IgE is not caused by the induction of IL-3 because anti-IL-3 antibodies did not abrogate the effect of IgE. 相似文献
62.
大分子解剖程序,配体分子契合适配和DOCK程序,以及计算化学的其它程序等,已集成为基于受体结构和分子间相互作用的进行分子设计的软件系统,定名为BIOS(Biomolecularinteractionsandorientationsimulator)。BIOS软件可在普通的微机上运行。使用BIOS分别剥离了细胞浆维甲结合蛋白(CRBP)和副睾维甲酸结合蛋白(E-RABP)两种蛋白的配体结合腔,剥离是围绕配体以同样的分子距离进行的。从而得到了芳香性残基分布相似的两个结合腔,其结合位点的几何排布却有相当差别。揭示出的结合腔已用于一系列的维甲类化合物的DOCK研究。E-RABP的结合腔可做为设计新维甲类分子的模板。 相似文献
63.
64.
Human Y chromosome azoospermia factors (AZF) mapped to different subregions in Yq11 总被引:56,自引:0,他引:56
Vogt PH; Edelmann A; Kirsch S; Henegariu O; Hirschmann P; Kiesewetter F; Kohn FM; Schill WB; Farah S; Ramos C; Hartmann M; Hartschuh W; Meschede D; Behre HM; Castel A; Nieschlag E; Weidner W; Grone HJ; Jung A; Engel W; Haidl G 《Human molecular genetics》1996,5(7):933-943
In a large collaborative screening project, 370 men with idiopathic
azoospermia or severe oligozoospermia were analysed for deletions of 76 DNA
loci in Yq11. In 12 individuals, we observed de novo microdeletions
involving several DNA loci, while an additional patient had an inherited
deletion. They were mapped to three different subregions in Yq11. One
subregion coincides to the AZF region defined recently in distal Yq11. The
second and third subregion were mapped proximal to it, in proximal and
middle Yq11, respectively. The different deletions observed were not
overlapping but the extension of the deleted Y DNA in each subregion was
similar in each patient analysed. In testis tissue sections, disruption of
spermatogenesis was shown to be at the same phase when the microdeletion
occurred in the same Yq11 subregion but at a different phase when the
microdeletion occurred in a different Yq11 subregion. Therefore, we propose
the presence of not one but three spermatogenesis loci in Yq11 and that
each locus is active during a different phase of male germ cell
development. As the most severe phenotype after deletion of each locus is
azoospermia, we designated them as: AZFa, AZFb and AZFc. Their probable
phase of function in human spermatogenesis and candidate genes involved
will be discussed.
相似文献
65.
FM Puca M de Tommaso P Tota V Sciruicchio 《Cephalalgia : an international journal of headache》1996,16(4):246-250
Fifty-eight migraineurs were. studied by intermediate frequency steady-state visual evoked potentials (SSVEPs) during headache-free periods. Sex, age, age of onset of migraine, duration of illness, type of migraine, side of pain, sleep .wake disorders, and frequency of migraine attacks did not correlate with any SSVEP abnormalities. On the other hand, visual responsiveness was significantly increased in subjects with family history of migraine, and in those with autonomic symptoms. Our results may indicate that a genetic predisposition to migraine underlies the observed abnormal visual response in migraineurs. 相似文献
66.
Nonpalpable breast lesions: recommendations for biopsy based on suspicion of carcinoma at mammography 总被引:12,自引:0,他引:12
Carcinoma was found in 30% (119 of 400) of biopsy specimens obtained for mammographically suspicious but nonpalpable findings. The authors reviewed the mammograms of these 400 cases without knowledge of the biopsy results and placed each examination into one of four groups based on their suspicion for carcinoma: minimal (n = 82), slight (n = 91), moderate (n = 174), and high (n = 53). In 127 cases, mammograms showed either minimally suspicious calcifications (n = 33) or minimally (n = 49) or slightly (n = 45) suspicious masses. A 4.7% (six of 127) rate of carcinoma was found in these groups; five of the six cancers were in situ. Had follow-up mammography been done rather than biopsy for these 127 less suspicious lesions, it is probable that the delay in diagnosis would not have altered overall prognosis. In the remaining 273 patients, the positive predictive value of mammography for carcinoma would have risen from 30% (119 of 400) to 41% (113 of 273). The authors conclude that in the management of suspicious nonpalpable mammographic findings, the rate of carcinoma for lesions at biopsy can approximate 40%. This is almost double the rate of most published series. 相似文献
67.
68.
69.
Greving JP Denig P de Zeeuw D Haaijer-Ruskamp FM 《European journal of clinical pharmacology》2006,62(2):129-133
Objective To investigate whether physicians’ attitudes towards treatment guidelines for primary and secondary care differ between teaching
and nonteaching hospitals shortly before and 4 years after the guidelines’ introduction.
Methods Possible barriers and facilitators of joint treatment guidelines were obtained by self-administered questionnaires twice during
the study period. Questionnaires were distributed among all internists and cardiologists in the Groningen region of The Netherlands.
Results Physicians from teaching and nonteaching hospitals differed in attitude regarding the content and usefulness of the guidelines.
Physicians from nonteaching hospitals more often believed that the guidelines are too restrictive (64% vs. 18%) and too rigid
to apply to individual patients (14% vs. 6%) and that they oversimplify medical practice (79% vs. 35%). Physicians from teaching
hospitals more often agreed that good recommendations for first-choice drugs had been made (76% vs. 50%) and that these guidelines
are a convenient source of advice (94% vs. 57%), can facilitate communication with general practitioners (94% vs. 71%), and
can improve the quality of pharmacotherapeutic care (88% vs. 43%). Four years later, a larger proportion of physicians from
both hospital settings had a negative attitude towards the usefulness of the guidelines, but the difference in attitude between
teaching and nonteaching hospitals remained the same.
Conclusion Physicians from nonteaching hospitals were less positive about the usefulness of joint treatment guidelines than physicians
from teaching hospitals were. Results from studies on the implementation of guidelines in teaching hospitals can therefore
not be transferred to nonteaching settings.
This research project was financed by an unconditional research grant from the Health Care Efficiency Programme of university
hospitals of the Health Care Insurance Board, The Netherlands. 相似文献
70.