全文获取类型
收费全文 | 16716篇 |
免费 | 1189篇 |
国内免费 | 45篇 |
专业分类
耳鼻咽喉 | 112篇 |
儿科学 | 402篇 |
妇产科学 | 276篇 |
基础医学 | 2189篇 |
口腔科学 | 619篇 |
临床医学 | 1657篇 |
内科学 | 3285篇 |
皮肤病学 | 203篇 |
神经病学 | 1605篇 |
特种医学 | 620篇 |
外科学 | 2162篇 |
综合类 | 149篇 |
一般理论 | 35篇 |
预防医学 | 1943篇 |
眼科学 | 279篇 |
药学 | 1227篇 |
中国医学 | 38篇 |
肿瘤学 | 1149篇 |
出版年
2024年 | 15篇 |
2023年 | 166篇 |
2022年 | 267篇 |
2021年 | 576篇 |
2020年 | 356篇 |
2019年 | 491篇 |
2018年 | 557篇 |
2017年 | 439篇 |
2016年 | 453篇 |
2015年 | 544篇 |
2014年 | 669篇 |
2013年 | 916篇 |
2012年 | 1357篇 |
2011年 | 1374篇 |
2010年 | 842篇 |
2009年 | 681篇 |
2008年 | 1160篇 |
2007年 | 1109篇 |
2006年 | 1035篇 |
2005年 | 1006篇 |
2004年 | 923篇 |
2003年 | 835篇 |
2002年 | 679篇 |
2001年 | 175篇 |
2000年 | 115篇 |
1999年 | 133篇 |
1998年 | 141篇 |
1997年 | 106篇 |
1996年 | 84篇 |
1995年 | 65篇 |
1994年 | 66篇 |
1993年 | 54篇 |
1992年 | 57篇 |
1991年 | 48篇 |
1990年 | 48篇 |
1989年 | 41篇 |
1988年 | 34篇 |
1987年 | 24篇 |
1986年 | 33篇 |
1985年 | 22篇 |
1984年 | 38篇 |
1983年 | 27篇 |
1982年 | 24篇 |
1981年 | 23篇 |
1980年 | 15篇 |
1979年 | 19篇 |
1978年 | 19篇 |
1976年 | 11篇 |
1974年 | 11篇 |
1973年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Autocrine motility factor (AMF) is one of the motility cytokines regulating tumor cell migration, therefore identification
of the signaling pathway coupled with it has critical importance. Previous studies revealed several elements of this pathway
predominated by lipoxygenase-PKC activations but the role for tyrosine kinases remained questionable. Motility cytokines frequently
have mitogenic effect as well, producing activation of overlapping signaling pathways therefore we have used B16a melanoma
cells as models where AMF has exclusive motility effect. Our studies revealed that in B16a cells AMF initiated rapid (1–5
min) activation of the protein tyrosine kinase (PTK) cascade inducing phosphorylation of 179, 125, 95 and 40/37 kD proteins
which was mediated by upstream cyclo- and lipoxygenases. The phosphorylated proteins were localized to the cortical actin-stress
fiber attachment zones in situ by confocal microscopy. On the other hand, AMF receptor activation induced significant decrease
in overall serine-phosphorylation level of cellular proteins accompanied by serine phosphorylation of 200, 90, 78 and 65 kd
proteins. The decrease in serine phosphorylation was independent of PTKs, PKC as well as cyclo- and lipoxygenases. However,
AMF induced robust translocation of PKCα to the stress fibers and cortical actin suggesting a critical role for this kinase
in the generation of the motility signal. Based on the significant decrease in serine phosphorylation after AMF stimulus in
B16a cells we postulated the involvement of putative serine/threonine phosphatase(s) upstream lipoxygenase and activation
of the protein tyrosine kinase cascade downstream cyclo- and lipoxygenase(s) in the previously identified autocrine motility
signal.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
42.
Rademakers R Melquist S Cruts M Theuns J Del-Favero J Poorkaj P Baker M Sleegers K Crook R De Pooter T Bel Kacem S Adamson J Van den Bossche D Van den Broeck M Gass J Corsmit E De Rijk P Thomas N Engelborghs S Heckman M Litvan I Crook J De Deyn PP Dickson D Schellenberg GD Van Broeckhoven C Hutton ML 《Human molecular genetics》2005,14(21):3281-3292
43.
Vincent M. Riccardi Helen M. Hittner Uta Francke Jorge J. Yunis David Ledbetter Wayne Borges 《Cancer Genetics and Cytogenetics》1980,2(2):131-137
The role of del (11)(p13) as a cause of aniridia, with and without Wilms tumor, is strengthened by demonstration of this chromosome aberration in 3 patients: monozygous twin girls, both of whom have aniridia and mental retardation and one of whom has a Wilms tumor; and an unrelated boy with aniridia and ambiguous genitalia. The break points defining the interstitial deletion for the twins are 11p13 and 11p15.1, while for the boy they are 11p1302 and 11p14.1. These patients and their karyotypes substantiate the critical importance of chromosome band 11p13 (or its hemizygous representation) in the development of aniridia and an associated Wilms tumor diathesis, as had been suggested previously (Riccardi VM, Sujansky E, Smith AC, Francke U, (1978): Pediatrics 61, 604-610). 相似文献
44.
Tim Martin Mark A McDaniel Melissa J Guynn Jon M Houck C Chad Woodruff Joel Pearson Bish Sandra N Moses Dubravko Kici? Claudia D Tesche 《International journal of psychophysiology》2007,64(3):247-258
We measured brain activity using magnetoencephalography in five participants during ongoing tasks that included prospective memory, retrospective memory, and oddball trials. Sources were identified in the hippocampal formation and posterior parietal and frontal lobes. Posterior parietal cortex activation had an earlier onset in the prospective memory condition than retrospective memory or oddball conditions, a higher level of theta activity in the retrospective condition, and higher levels of upper alpha in the prospective and oddball conditions. Activation of the hippocampal formation had a longer duration in the retrospective memory and prospective memory conditions than the oddball condition, but prominent alpha and theta band activity was present in all three conditions. We interpret the early (87 ms) onset of activity in parietal cortex as evidence for an initial noticing of appropriate conditions for a PM response. Hippocampal activity may reflect a subsequent memory search for the intended action. 相似文献
45.
46.
Tim A Holt David Stables Julia Hippisley-Cox Shaun O'Hanlon Azeem Majeed 《The British journal of general practice》2008,58(548):192-196
BACKGROUND: Around 1% of the UK population has diabetes that is either undiagnosed or unrecorded on practice disease registers. AIM: To estimate the number of people in UK primary care databases with biochemical evidence of undiagnosed diabetes. To develop simple practice-based search techniques to support early recognition of diabetes. DESIGN OF STUDY: Cross-sectional survey of 3 630 296 electronic records. SETTING: Four hundred and eighty UK practices contributing to the QRESEARCH database. METHOD: Electronic searches to identify people with no diabetes diagnosis in one of two categories (A and B), using the most recently recorded blood glucose measurement: random blood glucose level >or=11.1 mmol/l or fasting blood glucose level >or=7.0 mmol/l (A); either a random or a fasting blood glucose level >or=7.0 mmol/l (B). An additional outcome measure was the proportion of the population with at least one blood glucose measurement in the record. RESULTS: The number (percentage) identified in category A was 3758 (0.10% of the total population); the number in category B was 32 785 (0.90%). Projected to a practice of 7000 patients, around eight patients have biochemical evidence of undiagnosed diabetes, and 68 have results suggesting the need for further follow-up. One-third of people aged over 40 years without diabetes have a blood glucose measurement in the past 2 years in their record. CONCLUSION: People with possible undiagnosed diabetes are readily identifiable in UK primary care databases through electronic searches using blood glucose data. People with borderline levels, who may benefit from interventions to reduce their risk of progression to diabetes, can also be identified using practice-based software. 相似文献
47.
Three British physicians briefly review the final programs in a BBC series, "Doctors' Dilemmas," each consisting of a case history followed by a discussion involving health professionals, administrators, and lawyers. Taylor, an occupational physician, comments on the episode in which a company doctor is asked by management to disclose confidential information about an employee. Psychiatrist Jerram discusses his reactions to the program presenting the dilemmas of treating a patient with anorexia nervosa against her will. Forsythe, a community physician, reviews the final episode, which dealt with resource allocation, the role of health professionals within the National Health Service, and the potential conflict between the NHS and private practice. 相似文献
48.
Fürstenau Daniel Haneke Hannah Spies Claudia Walz Tim Schewina Kai Höft Moritz Mörgeli Rudolf Balzer Felix 《Zeitschrift fur Gesundheitswissenschaften》2022,30(1):99-110
Journal of Public Health - The purpose of this paper is to investigate the implementation of value-based care principles in the context of frailty in the perioperative process, highlighting the... 相似文献
49.
Neves Lia Mara Grosso Tim Carla Roberta Floriano Elaine Medeiros da Silva de Avó Lucimar Retto Fernandes João Batista Parizotto Nivaldo Antonio Cominetti Marcia Regina 《Lasers in medical science》2021,36(4):863-870
Lasers in Medical Science - Ultraviolet radiation (UVR) is the major etiologic agent of cutaneous photoaging, and different strategies are used to prevent and treat this condition. The... 相似文献
50.
Amanda Souza Setti Daniela Paes de Almeida Ferreira Braga Livia Vingris Assumpto Iaconelli Jr. Edson Borges Jr. 《Andrologia》2021,53(11):e14211
The objective of this study was to investigate the impact of male age, semen quality and days of ejaculatory abstinence on embryo morphokinetics. A total of 1,220 zygotes obtained from 139 couples in a private in vitro fertilisation centre were analysed. The timing of specific events from the point of insemination, such as timings to pronuclei appearance and fading, to two, three, four, five, six, seven and eight cells and to blastulation were recorded. Multivariate linear regression analysis was used to evaluate the influence of paternal factors on embryo morphokinetic events. Paternal age was positively correlated with delayed cell cleavage and blastulation, and negatively associated with implantation rate, and clinical pregnancy and live–birth chances. The ejaculatory abstinence was inversely correlated with the implantation rate. Inverse relationships were observed between semen parameters (sperm count, progressive sperm motility, total motile sperm count and morphology) and the timing of specific events during embryo development. Sperm morphology was also positively associated with implantation rate and pregnancy and live–birth chances. Increased paternal age and ejaculatory abstinence, and poor semen quality correlate with delayed cell cleavage and blastulation and negatively impact intracytoplasmic sperm injection outcomes. 相似文献