全文获取类型
收费全文 | 1162篇 |
免费 | 77篇 |
国内免费 | 14篇 |
学科分类
医药卫生 | 1253篇 |
出版年
2023年 | 17篇 |
2022年 | 22篇 |
2021年 | 41篇 |
2020年 | 16篇 |
2019年 | 19篇 |
2018年 | 24篇 |
2017年 | 23篇 |
2016年 | 28篇 |
2015年 | 38篇 |
2014年 | 48篇 |
2013年 | 56篇 |
2012年 | 68篇 |
2011年 | 76篇 |
2010年 | 45篇 |
2009年 | 53篇 |
2008年 | 73篇 |
2007年 | 79篇 |
2006年 | 74篇 |
2005年 | 60篇 |
2004年 | 47篇 |
2003年 | 50篇 |
2002年 | 54篇 |
2001年 | 7篇 |
1999年 | 9篇 |
1998年 | 33篇 |
1997年 | 30篇 |
1996年 | 28篇 |
1995年 | 16篇 |
1994年 | 14篇 |
1993年 | 12篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1966年 | 2篇 |
1964年 | 2篇 |
1959年 | 2篇 |
1958年 | 4篇 |
1957年 | 7篇 |
1956年 | 5篇 |
1955年 | 8篇 |
1954年 | 3篇 |
排序方式: 共有1253条查询结果,搜索用时 22 毫秒
1.
MOTOYOSHI NOMIZU YOSHIMASA INAGAKI TAKEYOSHI YAMASHITA AKO OHKUBO AKIRA OTAKA NOBUTAKA FUJII PETER P. ROLLER HARUAKI YAJIMA 《Chemical biology & drug design》1991,37(2):145-152
A new two-step deprotection/cleavage procedure for t-butoxycarbonyl (Boc) based solid phase peptide synthesis is reported. First the protective groups are removed from 4-(oxymethyl)-phenylacetamidomethyl (PAM) resin attached peptide with the weak hard acid, trimethylsilyl bromide-thioanisole/trifluoroacetic acid (TFA). In the second step, the peptide is cleaved from the resin with a stronger hard acid such as trimethylsilvl trifluoromethanesulfonate in TFA or with HF. The method is also shown to deformylate Nin-formyltryptophan moiety efficiently. The usefulness of this procedure for practical solid phase peptide synthesis is demonstrated by comparison with other deprotection methods in the synthesis of urotensin II and human endothelin. 相似文献
2.
TOSHIYASU SAKANE MOTOHIRO AKIZUKI YOKO TAKI SHINJI YAMASHITA HITOSHI SEZAKI TANEKAZU NADAI 《The Journal of pharmacy and pharmacology》1995,47(5):379-381
To clarify the relationship between the direct transport from the rat nasal cavity to the cerebrospinal fluid (CSF) and the molecular weight of the drug, the transport of fluorescein isothiocyanate-labelled dextran (FD) with various molecular weights was investigated. FDs (average molecular weights 4400 (FD4); 9400 (FD10); 18 900 (FD20); 40 500 Da (FD40)) were administered nasally or intravenously to rats, and the concentrations in the plasma and the CSF were measured and compared. None of the FDs were detected in the CSF after intravenous administration. However, FD4, FD10 and FD20 were observed to appear in the CSF after nasal administration, whereas the concentration in the plasma was much lower than that after intravenous administration. FD40 was not detected even after nasal administration. In addition, the concentration of these FDs in the CSF decreased with the increase in the molecular weight of FDs. These findings show that drugs with a molecular weight up to at least 20 000 Da can be directly transported from the nasal cavity to the CSF and that the transport of FDs to the CSF is dependent on their molecular weights. 相似文献
3.
Human T cell responses to recombinant mite antigens of Dermatophagoides farinae 总被引:1,自引:0,他引:1 下载免费PDF全文
We studied T cell responses to four glutathione S transferase (GST)-fused mite antigens prepared in our laboratory using peripheral blood lymphocytes from mite-sensitive patients with bronchial asthma. Of the four recombinant antigens, purified GST-Mag3 had the strongest ability to cause patients' lymphocytes to proliferate, and its potency was almost comparable to that of crude mite bodies (Dfb) and faeces (Dff) antigens and a purified major antigen, Der f 2. The responder lymphocytes were mainly T cells, because the proliferative response was depleted by the treatment of lymphocytes with anti-CD3 antibody and complement, but not with anti-CD20 antibody and complement. The responsiveness of lymphocytes to GST-Mag3 correlated with that to Der f 2, but GST-Mag3 displayed slightly higher activity to stimulate lymphocytes than Der f 2. Simultaneously, the levels of Dff- and GST-Mag3-specific IgE antibodies correlated with the responsiveness of lymphocytes to GST-Mag3. These results suggest that Mag3 is a new valuable antigen for the response of T cell proliferation in mite-sensitive patients. 相似文献
4.
5.
An ultrastructural study of cartilage resorption at the site of initial endochondral bone formation in the fetal mouse mandibular condyle 总被引:1,自引:1,他引:0
An ultrastructural study was undertaken on cartilage resorption at the site of initial endochondral bone formation in the mouse mandibular condyle on d 16 of pregnancy. After resorbing the bone collar, the osteoclasts extended their cell processes into the cartilage matrix and made contact with hypertrophic chondrocytes. By means of cell processes or vacuolar structures, these osteoclasts entrapped the calcified cartilage matrices, cell debris, and the degraded uncalcified cartilage matrices. In particular, since the calcified cartilage matrices were sometimes seen to be disrupted within the osteoclastic vacuolar structures, they were probably disposed of by the osteoclasts. Invading endothelial cells giving rise to capillaries also directly surrounded the degraded uncalcified cartilage matrices and small deposits of cell debris. In addition, hypertrophic chondrocytes that had attached to or were in the process of attaching to the invading osteoclasts often enclosed the small calcified cartilage matrices. Other cell types that have often been reported in other regions of cartilage resorption were not seen at the site of initial endochondral bone formation in this study. Our findings in relation to cartilage resorption may therefore represent unique features of the site of initial endochondral bone formation site. We consider that the manner of cartilage resorption is likely to vary by site, age, and species. 相似文献
6.
7.
TETSUYA TAKAHASHI HIROSHI YAMASHITA YU-XIANG ZHANG SHIGENOBU NAKAMURA 《Brain research bulletin》1996,41(6):363-367
In the present study, we examined the effect of amantadine on extracellular dopamine levels in the rat striatum using an in vivo microdialysis. Perfusion of amantadine (0.1–1 mM) through the microdialysis probe caused an increase both in extracellular dopamine and glutamate levels in rat striatum. Amantadine was found to increase extracellular dopamine concentration in Ca2+-dependent manner, but the effect was not abolished by ω-conotoxin. Although intraperitoneal administration of MK-801 [(+)-5-methyl-10,11-dihydroxy-5H-dibenzo(a,d)cyclohepten-5,10-imine] alone could not significantly alter the concentration of dopamine, it attenuated amantadine-induced increase in dopamine level. These findings suggest that an interaction between dopaminergic and glutamatergic neurotransmission is an important component in the regulation of striatal dopamine levels. Copyright © 1996 Elsevier Science Inc. 相似文献
8.
Takaaki Ohmori Ryo Tabei Norimasa Arita Mari Kondo Tetsuo Kozawa Yoshinori Chikamori Norifumi Ueda 《Pathology international》1983,33(5):999-1007
This report concerns a case of solitary extramedullary plasmacytoma of the left submandibular lymph node in a 56-year-old man. The tumor showed monoclonal proliferation of abnormal plasma cells which revealed highly positive stainings of both methylgreen pyronin and kappa light chain using the immunoperoxidase technique in the cytoplasms, and further revealed massive'.amyloid'deposits in the stroma, which suggested the possibility of sequential amyloid formation upon the secretion of paraprotein by tumor cells. 相似文献
9.
Kawano S Morotomi T Toyono T Nakamura N Uchida T Ohishi M Toyoshima K Harada H 《Connective tissue research》2002,43(2-3):409-412
Rat incisors grow continuously throughout life. Producing a variety of dental epithelial cells is performed by stem cells located in the cervical loop of the incisor apex. To study the mechanisms for cell differentiation, we established a dental epithelial cell line (HAT-7) originating from a cervical loop epithelium of a rat incisor. Immunochemical studies showed that HAT-7 produced the cells expressing amelogenin, ameloblastin, or alkaline phosphatase (ALP). To illustrate a role of Notch signaling in the determinant of the cell fate, we examined expression patterns of Notch1 and Jagged1 in HAT-7 density dependently. At lower cell density, Notch1- or Jagged1-expressing cells were not seen. However, when they were fully confluent, cells began to express Notch1 or Jagged1 strongly. Some ALP-positive cells were almost consistent with Notch1-expressing cells but not Jagged1-expressing cells. These results suggested that the determinant of direction of differentiation was associated with Notch signaling pathway. 相似文献
10.
Production of tumour necrosis factors by human T cells stimulated by a superantigen,toxic shock syndrome toxin-1 下载免费PDF全文
H. AKATSUKA K. IMANISHI K. INADA H. YAMASHITA M. YOSHIDA T. UCHIYAMA 《Clinical and experimental immunology》1994,96(3):422-426
The capacity of human T cell subsets, CD4+ or CD8+ T cells, to produce tumour necrosis factors (TNF-α and TNF-β) upon stimulation with toxic shock syndrome toxin-l (TSST-I) and the requirement for MHC ctass II molecules on accessory cells (AC) in the response were investigated. The capacity of CD4+ T cells was much higher than that of CD8+ T cells in TSST-1-induced production of TNF-α and TNF-β. The expression of MHC class II molecules on AC was required in the response. 相似文献