首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   213篇
  免费   9篇
  国内免费   3篇
  225篇
  2021年   1篇
  2020年   1篇
  2019年   2篇
  2018年   3篇
  2017年   2篇
  2016年   2篇
  2015年   5篇
  2014年   5篇
  2013年   10篇
  2012年   12篇
  2011年   8篇
  2010年   8篇
  2009年   6篇
  2008年   12篇
  2007年   12篇
  2006年   9篇
  2005年   7篇
  2004年   10篇
  2003年   8篇
  2002年   5篇
  2001年   4篇
  2000年   7篇
  1999年   7篇
  1998年   4篇
  1997年   3篇
  1996年   4篇
  1995年   4篇
  1994年   1篇
  1993年   2篇
  1992年   7篇
  1991年   5篇
  1990年   5篇
  1989年   5篇
  1988年   5篇
  1987年   2篇
  1986年   3篇
  1985年   2篇
  1984年   5篇
  1983年   3篇
  1982年   1篇
  1981年   1篇
  1979年   4篇
  1978年   1篇
  1977年   2篇
  1976年   2篇
  1975年   1篇
  1974年   2篇
  1973年   1篇
  1934年   1篇
  1929年   1篇
排序方式: 共有225条查询结果,搜索用时 0 毫秒
151.
The genetic variation in Zn-alpha 2-glycoprotein (ZAG) was investigated by polyacrylamide gel isoelectric focusing and immunoblotting. The samples comprised 590 Chinese from 2 localities (Shenyang: n = 390; Kaohsiung: n = 200) and 873 Koreans from 2 localities (Seoul: n = 523; Cheju: n = 350). The allele frequencies were: ZAG*1 = 0.9962, ZAG*5 = 0.0038 in Shenyang; ZAG*1 = 1.0000 in Kaohsiung; ZAG*1 = 0.9971, ZAG*3 = 0.0029 in Seoul, and ZAG*1 = 0.9929, ZAG*3 = 0.0071 in Cheju.  相似文献   
152.
Hermansky–Pudlak syndrome (HPS) is an autosomal recessive disorder characterized by oculocutaneous albinism (OCA), a bleeding tendency, and ceroid deposition. Most of the causative genes for HPS encode subunits of the biogenesis of lysosome‐related organelles complex (BLOC). In this study, we identified one patient each with HPS4, HPS6, and HPS9 by whole‐exome sequencing. Next, we analyzed hair samples from the three patients and representative patients with HPS1 and controls using electron microscopy and chemical methods. All HPS patients had fewer, smaller, and more immature melanosomes than healthy controls. Further, all patients showed reduced total melanin content and increased levels of benzothiazine‐type pheomelanin. The results of this study demonstrate the impact of the dysfunctions of BLOCs on the maturation of melanosomes and melanin levels and composition through analysis of their hair samples.  相似文献   
153.
Hepatitis B virus (HBV) infection is a worldwide health problem because of its potential to cause liver cirrhosis and hepatocellular carcinoma. Silibinin is a constituent of an extract of milk thistle, which is empirically used as a herbal medicine for the protection of liver, but its detailed effects on HBV are unknown. Because a previous study reported that silibinin hinders clathlin-mediated endocytosis (CME), we aimed to test whether silibinin inhibits the entry of HBV into hepatocytes. Using HepG2-NTCP-C4 cells, which overexpress sodium taurocholate cotransporting polypeptide (NTCP), it was shown that silibinin inhibited HBV infection dose-dependently. Similar effects were observed using human primary hepatocytes (PXB-cells). Additionally, a combination of silibinin and entecavir reduced HBV DNA in the culture supernatant more than either mono-treatment alone in HepG2-NTCP-C4 cells that had already been infected with HBV. Silibinin decreased transferrin uptake but did not affect the interaction between the HBV envelope and NTCP, suggesting that silibinin might inhibit HBV infection by hindering CME. In conclusion, this study showed that silibinin inhibits HBV entry in vitro.  相似文献   
154.
155.
Treatment of SJL lymph node, spleen, and thymus cells with anti-Ly 1.2 serum and C caused a marked reduction in the usually observed T-cell proliferation in response to syngeneic X-irradiated transplantable reticulum cell sarcoma cells. By contrast, treatment of lymphoid cells with anti-Ly 2.2 serum and C either failed to affect or increased the proliferative response. It is concluded that the Ly 1 cell is the major T-cell subpopulation which proliferates in response to RCS.  相似文献   
156.
The change of absorption spectra has been measured during the drying process of (31 R)bacteriochlorophyll (BChl) c from diethyl ether, dichloromethane (CH2Cl2) and carbon tetrachloride (CCl4) solutions. Absorption maxima of the Qy(0–0) transition of BChl c appear at 659 nm in diethyl ether, 680 nm in CH2Cl2 and 710 nm in CCl4. All these peaks are red-shifted to about 740 nm with formation of solid high aggregates when the solutions are completely dried. Fourier transform infrared spectra of the three solid aggregates are almost identical. However, magnetic circular dichroism and circular dichroism spectra are different and can be explained in terms of variations in stacking size of the aggregates and molecular arrangement of BChl c. Small-angle X-ray diffraction has been observed only for the aggregates treated with CH2Cl2, and the same sample gave rise to highly resolved cross polarization/magic angle spinning 13C nuclear magnetic resonance spectrum. The results suggest that molecular ordering of the solid-state BChl c aggregates is highly dependent on the formation process which is largely determined by the solvent used.  相似文献   
157.
Fourteen native strains of Trichoderma spp. from wildand agricultural pathosystems in the state of Yucatan, Mexico, with growth-promoting ability of Capsicum chinense Jacq. seedlings were evaluated and antagonistic effect of their filtrate against second-stage juveniles (J2) of Meloidogyne incognita. The strains Th05-02 and Th27-08 showed the best significant effects on plant hight variable increments 55.57 and 47.62%, theTh07-04 with 29.48% more root length, theTh02-01 and Th07-04 isolates increased from 48.71 to 84.61% in volume radical and 53.40% of total dry biomass. Statistical analysis (p≤0.001) of Th43 and Th43-13-14 filtrates caused 100% mortality at 24 and 48h. In the test of reversibility to 24 h after replacing the filtrates Th43-13, Th43-14, TH09-06 and TH20-07 by sterile distilled water, the J2 did not recover their viability, so they were considered as the best potential strains of Trichoderma spp. with antagonistic capacity in J2 of M.incognita.  相似文献   
158.
We previously reported the construction and activity of a humanized, bispecific diabody (hEx3) that recruited T cells towards an epidermal growth factor receptor (EGFR) positive tumor. Herein, we describe the construction of a second functional, fully humanized, anti-EGFR bispecific diabody that recruits another subset of lymphocyte effectors, the natural killer cells, to EGFR-expressing tumor cells. After we confirmed that an anti-EGFR?×?anti-CD16 bispecific diabody (Ex16) consisting of a previously humanized anti-EGFR variable fragment (Fv) and a mouse anti-CD16 Fv had growth inhibitory activity, we designed a humanized anti-CD16 Fv to construct the fully humanized Ex16 (hEx16). However, the humanized form had lower activity for inhibition of cancer growth. To restore its growth inhibitory activity, we introduced mutations into the Vernier zone, which is located near the complementarity-determining regions and is involved in their binding activity. We efficiently prepared 15 different hEx16 mutants by expressing each chimeric single-chain component for hEx16 separately. We then used our in vitro refolding system to select the most functional mutant, which had a growth inhibitory effect comparable with that of the commercially available chimeric anti-EGFR antibody, cetuximab. Our refolding system could aid in the efficient optimization of other proteins with heterodimeric structure.  相似文献   
159.
Antibodies, with their high affinity and specificity, are widely utilized in the field of protein engineering, medicinal chemistry, and nanotechnology applications, and our recent studies have demonstrated the recognition and binding of antibody for the surface on inorganic material. In this study, we generated a high-affinity gold-binding antibody fragment by a combination of peptide-grafting and phage-display techniques and showed the availability of the material-binding fragment for one-pot functionalization of nanoparticles as interface molecules. After a gold-binding peptide sequence was grafted into one of the complementarity determining regions of a single variable domain of a heavy-chain camel antibody, a combinatorial library approach raised by 20 times the affinity of the peptide-grafted fragment. The high-affinity gold-binding fragment (E32) spontaneously adsorbed on gold nanoparticles, and consequently the nanoparticles formed a stable dispersion in a high-ionic-strength solution. Multivalent and bispecific antibodies constructed on the E32 platform by means of fusion technology functionalized gold nanoparticles in one pot, and these functionalized nanoparticles could be used to obtain surface plasmon resonance scattering images of cancer cells and to spontaneously link two different nanomaterials. Here, we propose the bispecific antibodies as convenient interface molecules in the nanosized world.  相似文献   
160.

Key message

Nitrogen levels can modulate the effectiveness of clubroot resistance in an isolate- and host-specific manner. While the same QTL were detected under high and low nitrogen, their effects were altered.

Abstract

Clubroot, caused by Plasmodiophora brassicae, is one of the most damaging diseases of oilseed rape and is known to be affected by nitrogen fertilization. However, the genetic factors involved in clubroot resistance have not been characterized under nitrogen-limiting conditions. This study aimed to assess the variability of clubroot resistance under different nitrogen levels and to characterize the impact of nitrogen supply on genetic resistance factors. Linkage analyses and a genome-wide association study were conducted to detect QTL for clubroot resistance and evaluate their sensitivity to nitrogen. The clubroot response of a set of 92 diverse oilseed rape accessions and 108 lines derived from a cross between ‘Darmor-bzh’ (resistant) and ‘Yudal’ (susceptible) was studied in the greenhouse under high- and low-nitrogen conditions, following inoculation with the P. brassicae isolates eH and K92-16. Resistance to each isolate was controlled by a major QTL and a few small-effects QTL. While the same QTL were detected under both high and low nitrogen, their effects were altered. Clubroot resistance to isolate eH, but not K92-16, was greater under a low-N supply versus a high-N supply. New sources of resistance were found among the oilseed rape accessions under both low and high-N conditions. The results are discussed relative to the literature and from a crop improvement perspective.
  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号