全文获取类型
收费全文 | 1450篇 |
免费 | 57篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 40篇 |
妇产科学 | 13篇 |
基础医学 | 224篇 |
口腔科学 | 34篇 |
临床医学 | 85篇 |
内科学 | 292篇 |
皮肤病学 | 11篇 |
神经病学 | 63篇 |
特种医学 | 71篇 |
外科学 | 172篇 |
综合类 | 15篇 |
预防医学 | 59篇 |
眼科学 | 19篇 |
药学 | 115篇 |
中国医学 | 1篇 |
肿瘤学 | 265篇 |
出版年
2023年 | 7篇 |
2022年 | 12篇 |
2021年 | 23篇 |
2020年 | 15篇 |
2019年 | 12篇 |
2018年 | 17篇 |
2017年 | 17篇 |
2016年 | 19篇 |
2015年 | 35篇 |
2014年 | 42篇 |
2013年 | 62篇 |
2012年 | 83篇 |
2011年 | 92篇 |
2010年 | 64篇 |
2009年 | 35篇 |
2008年 | 72篇 |
2007年 | 100篇 |
2006年 | 75篇 |
2005年 | 83篇 |
2004年 | 85篇 |
2003年 | 102篇 |
2002年 | 88篇 |
2001年 | 9篇 |
2000年 | 22篇 |
1999年 | 15篇 |
1998年 | 17篇 |
1997年 | 13篇 |
1996年 | 15篇 |
1995年 | 28篇 |
1994年 | 24篇 |
1993年 | 19篇 |
1992年 | 14篇 |
1991年 | 17篇 |
1990年 | 9篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 13篇 |
1986年 | 6篇 |
1984年 | 10篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1981年 | 11篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 12篇 |
1977年 | 13篇 |
1976年 | 5篇 |
1975年 | 8篇 |
1974年 | 5篇 |
1969年 | 6篇 |
排序方式: 共有1514条查询结果,搜索用时 11 毫秒
51.
52.
We have investigated the potential of neurotropic microbes to invade the central nervous system (CNS) via the peripheral nervous system. Herpes simplex virus type 1 (HSV-1) strain KH6 and herpes simplex virus type 2 (HSV-2) strain 186 were found to infect chemosensory neurons in the vomeronasal organ (the pheromone detector) following intranasal inoculation of mice. HSV-1 strain KH6 infection was further transmitted to the accessory olfactory bulb (first relay), the medial amygdala (second relay), and the bed nucleus of the stria terminalis and the ventromedial hypothalamus (third relay). HSV-1 strain KH6 also targeted the olfactory and trigeminal systems. HSV-2 strain 186 predominantly attacked the brainstem including the trigeminal system. While both viruses did not induce apoptosis in infected chemosensory neurons, they did in infected brain tissue. These results suggest that neurotropic viruses can invade the brain by infecting vomeronasal chemosensory neurons and that the restrained induction of apoptosis in the infected neurons may facilitate viral transmission to the CNS. 相似文献
53.
Junichi Hasegawa Akihiko Sekizawa Tomoaki Ikeda Mitsuhiko Koresawa Isamu Ishiwata Masakiyo Kawabata 《The journal of maternal-fetal & neonatal medicine》2016,29(10):1652-1656
Objectives: To clarify the clinical risk factors associated with poor neonatal outcomes due to umbilical cord prolapse (UCP).Methods: A postal questionnaire survey was attempted in Japan. The clinical risk factors and managements associated with poor neonatal outcomes were analyzed in cases of UCP treated in Japan.Results: A total of 267 cases of UCP (out of 2?037?460 total deliveries) were analyzed. The rates of intrauterine death, neonatal death and survival with disability were 3.4%, 5.6% and 7.1%, respectively. The multivariate regression analysis for these poor neonatal outcomes revealed that the significant risk factors included a prolapsed amniotic sac (adjusted odds ratio (aOR), 4.49), preterm labor (aOR, 2.99) and replacement of the prolapsed umbilical cord into the uterus (aOR, 2.87). However, UCP that occurred during labor (aOR, 0.28) and emergency cesarean section (aOR, 0.11) were associated with a reduction in the rates of poor outcomes. The interval between the diagnosis of UCP and delivery was significantly longer in the infants with a poor outcome than intact survival (median 30 versus 24?min, p?=?0.048).Conclusion: An emergency cesarean section should be carried out immediately to ensure a better outcome for the infant. 相似文献
54.
Hirano W Gotoh I Uekita T Seiki M 《Genes to cells : devoted to molecular & cellular mechanisms》2005,10(6):565-574
MTCBP-1 was identified as a protein that binds the cytoplasmic tail of membrane-type 1 matrix metalloproteinase (MT1-MMP/MMP-14). Since MTCBP-1 has a putative beta-barrel structure, it is presumably a member of the recently proposed cupin superfamily that contains tremendously diverged functions of proteins in spite of their well-conserved beta-barrel structure. MTCBP-1 shows significant homology to the bacterial aci-reductone dioxygenase (ARD) in the cupin family, which is an enzyme in the methionine salvage pathway (MTA cycle). Since it is difficult to speculate the functions of cupin proteins simply based on their sequence homology, we examined whether the eukaryotic ARD homologs surely function in the methionine metabolism. Under sulfur-depleted conditions, yeast could grow when substrate of MTA cycle was provided. Disruption of the yeast ARD homolog, YMR009w gene, abolished ability of the cells to grow in this culture condition. Re-expression of either the YMR009w or MTCBP-1 gene restored the cell growth. Mutation analysis revealed that the glutamic acid residue in the beta-barrel fold and the N-terminal extension from the beta-barrel fold were found to be important for the activity to restore the growth. Thus, MTCBP-1 isolated as a binding protein for MT1-MMP was demonstrated to function as an ARD-like enzyme in the MTA cycle in yeast. 相似文献
55.
Banno S Noguchi R Yamashita K Fukumori F Kimura M Yamaguchi I Fujimura M 《Current genetics》2007,51(3):197-208
Neurospora crassa has a putative histidine phosphotransfer protein (HPT-1) that transfers signals from 11 histidine kinases to two putative
response regulators (RRG-1 and RRG-2) in its histidine-to-aspartate phosphorelay system. The hpt-1 gene was successfully disrupted in the os-2 (MAP kinase gene) mutant, but not in the wild-type strain in this study. Crossing the resultant hpt-1; os-2 mutants with the wild-type or os-1 (histidine kinase gene) mutant strains produced no progeny with hpt-1 or os-1;
hpt-1 mutation, strongly suggesting that hpt-1 is essential for growth unless downstream OS-2 is inactivated. hpt-1 mutation partially recovered the osmotic sensitivity of os-2 mutants, implying the involvement of yeast Skn7-like RRG-2 in osmoregulation. However, the rrg-2 disruption did not change the osmotic sensitivity of the wild-type strain and the os-2 mutant, suggesting that rrg-2 did not participate in the osmoregulation. Both rrg-2 and os-2 single mutation slightly increased sensitivity to t-butyl hydroperoxide, and rrg-2 and hpt-1 mutations increased the os-2 mutant’s sensitivity. Although OS-1 is considered as a positive regulator of OS-2 MAP kinase, our results suggested that
HPT-1 negatively regulated downstream MAP kinase cascade, and that OS-2 and RRG-2 probably participate independently in the
oxidative stress response in N. crassa. 相似文献
56.
Akinobu Hibino Hiroki Kondo Hironori Masaki Yoshinari Tanabe Isamu Sato Nobuhiro Takemae Takehiko Saito Hassan Zaraket Reiko Saito 《Virus genes》2017,53(1):89-94
We report five cases of community- and hospital-acquired infections with oseltamivir- and peramivir-resistant A(H1N1)pdm09 viruses possessing the neuraminidase (NA) H275Y mutation during January–February 2016 in Japan. One case was hospitalized and was receiving oseltamivir for prophylaxis. The remaining four cases were not taking antiviral drugs at the time of sampling. These cases were geographically distant and epidemiologically unrelated. The five viruses showed ~300-fold rise in IC50 values against oseltamivir and peramivir, defined as highly reduced inhibition according to the WHO definition. Overall, the prevalence of the H275Y A(H1N1)pdm09 viruses was 1.8 % (5/282). The resistant viruses possessed the V241I, N369 K, and N386 K substitutions in the NA that have been previously reported among A(H1N1)pdm09 to alter transmission fitness. Analysis of Michaelis constant (Km) revealed that two of the isolates had reduced NA affinity to MUNANA, while the other three isolates displayed a slightly decreased affinity compared to the sensitive viruses. Further studies are needed to monitor the community spread of resistant viruses and to assess their transmissibility. 相似文献
57.
Suzuki Y Saito R Sato I Zaraket H Nishikawa M Tamura T Dapat C Caperig-Dapat I Baranovich T Suzuki T Suzuki H 《Journal of clinical microbiology》2011,49(1):125-130
Neuraminidase inhibitors are agents used against influenza viruses; however, the emergence of drug-resistant strains is a major concern. Recently, the prevalence of oseltamivir-resistant seasonal influenza A (H1N1) virus increased globally and the emergence of oseltamivir-resistant pandemic influenza A (H1N1) 2009 viruses was reported. In this study, we developed a cycling probe real-time PCR method for the detection of oseltamivir-resistant seasonal influenza A (H1N1) and pandemic influenza A (H1N1) 2009 viruses. We designed two sets of primers and probes that were labeled with 6-carboxyfluorescein or 6-carboxy-X-rhodamine to identify single nucleotide polymorphisms (SNPs) that correspond to a histidine and a tyrosine at position 275 in the neuraminidase protein, respectively. These SNPs confer susceptibility and resistance to oseltamivir, respectively. In the 2007-2008 season, the prevalence of oseltamivir-resistant H1N1 viruses was 0% (0/72), but in the 2008-2009 season, it increased to 100% (282/282). In the 2009-2010 season, all of the pandemic influenza A (H1N1) 2009 viruses were susceptible to oseltamivir (0/73, 0%). This method is sensitive and specific for the screening of oseltamivir-resistant influenza A (H1N1) viruses. This method is applicable to routine laboratory-based monitoring of drug resistance and patient management during antiviral therapy. 相似文献
58.
Synthesis of Unsaturated Nonionic Poly(ester‐sulfones) via Acyclic Diene Metathesis (ADMET) Polymerization and Anode‐Selective Electrophoretic Deposition 下载免费PDF全文
Nonionic aliphatic polymers containing ester and sulfonyl moieties, [poly(ester‐sulfones)s] were found to undergo anode‐selective electrophoresis under electrophoretic deposition conditions. Herein are reported the syntheses of unsaturated nonionic polyesters containing sulfide linkages and double bonds on the polymer backbone via acyclic diene metathesis polymerization using a Grubbs' catalyst. Subsequent oxone oxidation was carried out, affording the corresponding poly(ester‐sulfone), followed by electrophoretic deposition of the unsaturated poly(ester‐sulfone) onto stainless steel. Subsequent UV‐irradiation cured the deposited film, improving the peeling strength of the coating.
59.
Koide N Sugiyama T Mori I Mu MM Hamano T Yoshida T Yokochi T 《Clinical and diagnostic laboratory immunology》2002,9(6):1169-1174
The in vitro effects of gamma interferon (IFN-gamma) on the mouse CD5(+) B1-cell line, TH2.52, a hybridoma between mouse B lymphoma and mouse splenic B cells that expresses a series of B1 markers, were investigated. A significant number of macrophage-like cells appeared in the cultures of TH2.52 cells exposed to IFN-gamma, these adhering to plastic dishes and exhibiting phagocytic activity. Positive for esterase staining, the macrophage-like cells returned to the original TH2.52 morphology upon removal of IFN-gamma. The change was prevented by treatment with SB202190, an inhibitor of p38 mitogen-activated protein (MAP) kinase and by transfection of a p38 MAP kinase dominant-negative mutant. Further, interleukin-4 (IL-4) inhibited IFN-gamma-induced phosphorylation of p38 MAP kinase and the appearance of macrophage-like cells. IFN-gamma and IL-4 exhibited contradictory actions on morphological change of CD5(+) B1 cells into macrophage-like cells. Differential regulation of CD5(+) B1 cells by IFN-gamma, a Th1 cytokine, and IL-4, a Th2 cytokine, may have clear immunological significance. 相似文献
60.