全文获取类型
收费全文 | 24926篇 |
免费 | 2503篇 |
国内免费 | 1407篇 |
专业分类
耳鼻咽喉 | 216篇 |
儿科学 | 338篇 |
妇产科学 | 170篇 |
基础医学 | 2558篇 |
口腔科学 | 549篇 |
临床医学 | 2821篇 |
内科学 | 3569篇 |
皮肤病学 | 480篇 |
神经病学 | 1429篇 |
特种医学 | 1198篇 |
外国民族医学 | 5篇 |
外科学 | 3615篇 |
综合类 | 4281篇 |
现状与发展 | 4篇 |
一般理论 | 3篇 |
预防医学 | 1831篇 |
眼科学 | 451篇 |
药学 | 2207篇 |
33篇 | |
中国医学 | 1227篇 |
肿瘤学 | 1851篇 |
出版年
2024年 | 95篇 |
2023年 | 415篇 |
2022年 | 978篇 |
2021年 | 1330篇 |
2020年 | 1116篇 |
2019年 | 859篇 |
2018年 | 877篇 |
2017年 | 841篇 |
2016年 | 841篇 |
2015年 | 1198篇 |
2014年 | 1400篇 |
2013年 | 1589篇 |
2012年 | 2195篇 |
2011年 | 2193篇 |
2010年 | 1585篇 |
2009年 | 1323篇 |
2008年 | 1494篇 |
2007年 | 1459篇 |
2006年 | 1350篇 |
2005年 | 1143篇 |
2004年 | 904篇 |
2003年 | 898篇 |
2002年 | 696篇 |
2001年 | 451篇 |
2000年 | 312篇 |
1999年 | 204篇 |
1998年 | 135篇 |
1997年 | 116篇 |
1996年 | 95篇 |
1995年 | 80篇 |
1994年 | 84篇 |
1993年 | 44篇 |
1992年 | 61篇 |
1991年 | 45篇 |
1990年 | 38篇 |
1989年 | 35篇 |
1988年 | 29篇 |
1987年 | 36篇 |
1986年 | 42篇 |
1985年 | 36篇 |
1984年 | 26篇 |
1983年 | 24篇 |
1982年 | 22篇 |
1981年 | 18篇 |
1980年 | 18篇 |
1979年 | 21篇 |
1978年 | 10篇 |
1976年 | 8篇 |
1968年 | 6篇 |
1957年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
Horimoto T. Limcumpao J. A. Xuan X. Ono M. Maeda K. Kawaguchi Y. Kai C. Takahashi E. Mikami T. 《Archives of virology》1992,126(1-4):283-292
Summary Heterogeneity of 9 feline herpesvirus type 1 (FHV-1) strains consisting of the prototype C27 strain, one French isolate, six Japanese isolates, and the attenuated vaccine F2 strain was examined by biological, immunological, and molecular biological methods. No significant difference was observed in virus growth and antigenic properties among the strains in Crandell feline kidney cell cultures. Hemagglutination activity was also detected in all extracts of cells infected with each strain. However, in immunoblot analysis, a virus-structural immunogenic protein with an Mr of 36 kDa was lacking in 2 strains, one of which was the vaccine F2 strain, whereas the other immunogenic proteins including three kinds of major glycoproteins were detected in all strains without differences in electrophoretic mobilities. Furthermore, when restriction endonuclease analysis was performed to examine the genomic heterogeneity of strains, the cleavage patterns with the enzymeMluI showed a genomic heterogeneity between wild and vaccine strains. In contrast, only a slight variation in the sizes of some fragments was shown with most of the 7 other enzymes used. These results indicated that the lack of the 36 kDa protein and theMluI cleavage pattern could be used as markers of the vaccine F2 strain. The specific markers are important not only to control the quality of the vaccine but also to evaluate the vaccine immunity in FHV-1 infection in cats. 相似文献
22.
Modulating parameters of excitability during and after transcranial direct current stimulation of the human motor cortex 总被引:2,自引:1,他引:2
Michael A. Nitsche Antje Seeber Kai Frommann Cornelia Carmen Klein Christian Rochford Maren S. Nitsche Kristina Fricke David Liebetanz Nicolas Lang rea Antal Walter Paulus Frithjof Tergau 《The Journal of physiology》2005,568(1):291-303
Weak transcranial direct current stimulation (tDCS) of the human motor cortex results in excitability shifts which occur during and after stimulation. These excitability shifts are polarity-specific with anodal tDCS enhancing excitability, and cathodal reducing it. To explore the origin of this excitability modulation in more detail, we measured the input–output curve and motor thresholds as global parameters of cortico-spinal excitability, and determined intracortical inhibition and facilitation, as well as facilitatory indirect wave (I-wave) interactions. Measurements were performed during short-term tDCS, which elicits no after-effects, and during other tDCS protocols which do elicit short- and long-lasting after-effects. Resting and active motor thresholds remained stable during and after tDCS. The slope of the input–output curve was increased by anodal tDCS and decreased by cathodal tDCS. Anodal tDCS of the primary motor cortex reduced intracortical inhibition and enhanced facilitation after tDCS but not during tDCS. Cathodal tDCS reduced facilitation during, and additionally increased inhibition after its administration. During tDCS, I-wave facilitation was not influenced but, for the after-effects, anodal tDCS increased I-wave facilitation, while cathodal tDCS had only minor effects. These results suggest that the effect of tDCS on cortico-spinal excitability during a short period of stimulation (which does not induce after-effects) primarily depends on subthreshold resting membrane potential changes, which are able to modulate the input-output curve, but not motor thresholds. In contrast, the after-effects of tDCS are due to shifts in intracortical inhibition and facilitation, and at least partly also to facilitatory I-wave interaction, which is controlled by synaptic activity. 相似文献
23.
24.
25.
26.
Different applications of polymerases with and without proofreading activity in single-nucleotide polymorphism analysis 总被引:2,自引:0,他引:2
Zhang J Li K Liao D Pardinas JR Chen L Zhang X 《Laboratory investigation; a journal of technical methods and pathology》2003,83(8):1147-1154
With the completion of the human genome project, single-nucleotide polymorphisms (SNPs) have become the focus of intense study in biomedical research. Polymerase-mediated primer extension has been employed in a variety of SNP assays. However, these SNP assays using polymerase without proofreading function are compromised by their low reliability. Using a newly developed short amplicon harboring restriction enzyme site, EcoR-I, we were able to compare the single-base discrimination abilities of polymerases with and without proofreading function in primer extension in a broad range of annealing temperatures. Thermodynamic analysis demonstrated a striking single-nucleotide discrimination ability of polymerases with proofreading function. Using unmodified 3'-end allele-specific primers, only template-dependent products were generated by polymerase with proofreading activity. This powerful single-base discrimination ability of exo(+) polymerases was further evaluated in primer extension using three types of 3' terminally modified allele-specific primers. As compared with the poor fidelity in primer extension of polymerases lacking 3' exonuclease activity, this study provides convincing evidence that the use of proofreading polymerases in combination with 3'-end modified allele-specific primers can be a powerful new strategy for the development of SNP assays. 相似文献
27.
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
28.
29.
目的 观察家兔面神经急性损伤后髓鞘和轴索的组织病理变化。方法 用丝线结扎茎乳孔以外的面神经总干 ,观察结扎后 1天、3天及 5天面神经的组织病理改变。结果 家兔面神经受损后 ,先后在髓鞘和轴索出现轻重不等、程度不同的形态学改变。结论 结扎家兔面神经后 ,其髓鞘及轴索会出现相应的病理改变 ,且随着结扎天数的增加 ,面神经损伤亦呈加重的趋势 相似文献
30.
Kai Dong Mengjun Shen Guanqun Ju Sha Han Zhijun Wang Kaining Lu Dongliang Xu 《European urology》2021,79(2):283-289
BackgroundPartial nephrectomy or angioembolisation is commonly used for sporadic renal angiomyolipomas (RAMLs) with high RENAL scores, but there is a risk of reduced renal function, postoperative complications, and recurrence.ObjectiveTo describe a new technique for off-clamp laparoscopic evacuation of sporadic RAMLs with high RENAL scores that promotes maximal renal function maintenance and low postoperative complication and lesion recurrence rates.Design, setting, and participantsA retrospective cohort of patients undergoing off-clamp laparoscopic evacuation for sporadic RAMLs with RENAL scores ≥9 from January 2013 to June 2018 was included.Surgical procedureWe highlighted the curettage, suction, packing, and binding (CSPB) technique, a new off-clamp retroperitoneoscopic evacuation technique for sporadic RAMLs.MeasurementsDemographics, preoperative, intraoperative, and postoperative outcomes were assessed.Results and limitationsA total of 141 cases were included. The median (interquartile range [IQR]) tumour size was 7 (6.2–8.2) cm. The median (IQR) RENAL score was 10 (9–11). The median (IQR) operative time was 80 (65–125) min, with a median (IQR) estimated blood loss of 130 (90–362.5) ml. Conversion to neither open surgery nor standard laparoscopy occurred. The warm ischaemia time was zero for all cases. Postoperatively, 13 minor complications (Clavien grade 1) were recorded. No blood transfusions were reported. The glomerular filtration rate did not change significantly from preoperative period to 12-mo follow-up. Recurrence did not occur at the median follow-up period of 48 (36–60) mo. The retrospective design and lack of a control group are limitations of this study.ConclusionsOff-clamp retroperitoneoscopic tumour evacuation using the CSPB technique is feasible, safe, and effective for treating complex sporadic RAMLs.Patient summaryWe report a curettage, suction, packing, and binding technique for off-clamp retroperitoneoscopic evacuation of sporadic renal angiomyolipomas that leads to complete lesion clearance, excellent renal function preservation, and minimal perioperative complications. 相似文献