全文获取类型
收费全文 | 895篇 |
免费 | 34篇 |
专业分类
929篇 |
出版年
2021年 | 8篇 |
2019年 | 8篇 |
2018年 | 9篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 24篇 |
2014年 | 21篇 |
2013年 | 61篇 |
2012年 | 37篇 |
2011年 | 26篇 |
2010年 | 22篇 |
2009年 | 23篇 |
2008年 | 24篇 |
2007年 | 35篇 |
2006年 | 40篇 |
2005年 | 24篇 |
2004年 | 33篇 |
2003年 | 37篇 |
2002年 | 51篇 |
2001年 | 25篇 |
2000年 | 32篇 |
1999年 | 24篇 |
1998年 | 11篇 |
1997年 | 12篇 |
1996年 | 8篇 |
1994年 | 11篇 |
1993年 | 5篇 |
1992年 | 21篇 |
1991年 | 19篇 |
1990年 | 19篇 |
1989年 | 14篇 |
1988年 | 15篇 |
1987年 | 18篇 |
1986年 | 7篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1983年 | 11篇 |
1982年 | 11篇 |
1981年 | 7篇 |
1980年 | 16篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 17篇 |
1975年 | 12篇 |
1974年 | 15篇 |
1973年 | 8篇 |
1972年 | 10篇 |
1970年 | 9篇 |
1966年 | 5篇 |
排序方式: 共有929条查询结果,搜索用时 0 毫秒
81.
82.
83.
The gerreid species,Gerres baconensis (Evermann &; Seale),G. equulus Temminck &; Schlegel andG. oyena (Forsskål), were re-assessed as valid following examination of their holotypes and other specimens, and included in the “G. oyena complex”.Gerres haconensis is currently known only from Bacon, Luzon Island, Philippines and the Ogasawara (=Bonin) Islands, Japan, andG. equulus only from southern Japan (except Ryukyu Islands) and southern Korea.Gerres oyena is widely distributed in the Indo-West Pacific (in Japan, only from the Ryukyu Islands).Gerres baconensis differs from bothG. equulus andG. oyena in having higher counts of both the pored lateral line scales (39–42 vs 35–41 in the latter two species) and the lower gill raker series (8 or 9 vs. usually 7). A U-shaped premaxillary groove, formed on the dorsum of the forehead by the long ascending processes of the premaxillae, is scaleless inG. equulus andG. oyena, whereas it is fully scaled just behind the level of the posterior nostrils inG. baconensis over ca. 160 mm in standard length (SL) (partially scaled in specimens of ca. 100 mm SL).Gerres equulus differs fromG. oyena in having the posterior margin of the maxilla not extending beyond a vertical through the anterior margin of the inner dermal eye opening, shorter second dorsal and anal fin spines (means 18.5% and 8.5% of SL, respectively vs. 21.2% and 10.3% of SL), lower body depth at first anal fin spine base (27.0% vs. 29.6% of SL) and dorsomedial U-shaped groove scaleles throughout life (vs. tiny squamation anteriorly in specimens over ca. 130 mm SL). OtherGerres species of uncertain status and/or related species are discussed. 相似文献
84.
Yoshino H Sato H Shiraishi T Tachibana K Emura T Honma A Ishikura N Tsunenari T Watanabe M Nishimoto A Nakamura R Nakagawa T Ohta M Takata N Furumoto K Kimura K Kawata H 《Bioorganic & medicinal chemistry》2010,18(23):8150-8157
A series of 5,5-dimethylthiohydantoin derivatives were synthesized and evaluated for androgen receptor pure antagonistic activities for the treatment of castration-resistant prostate cancer. Since CH4933468, which we reported previously, had a problem with agonist metabolites, novel thiohydantoin derivatives were identified by applying two strategies. One was the replacement of the alkylsulfonamide moiety by a phenylsulfonamide to avoid the production of agonist metabolites. The other was the replacement of the phenyl ring with a pyridine ring to improve in vivo potency and reduce hERG affinity. Pharmacological assays indicated that CH5137291 (17b) was a potent AR pure antagonist which did not produce the agonist metabolite. Moreover, CH5137291 completely inhibited in vivo tumor growth of LNCaP-BC2, a castration-resistant prostate cancer model. 相似文献
85.
In this work, we examined the antioxidant role of mucin, a typical sialic acid containing high-molecular weight glycoprotein. The function of mucin as a hydroxyl radical (.OH) scavenger was characterized using bovine submaxillary gland mucin (BSM). Non-treated BSM effectively protected DNA from the attack of .OH; however, desialylated BSM lost this potential. Moreover, we estimated the scavenging effects of BSM against .OH generated by UV irradiation of hydrogen peroxide using ESR analysis. Our results indicate that BSM has .OH scavenging ability the and sialic acid in mucin is an essential moiety to scavenge .OH. 相似文献
86.
87.
Noncovalent Immobilization of Streptavidin on In Vitro- and In Vivo-Biotinylated Bacterial Magnetic Particles 下载免费PDF全文
Yoshiaki Maeda Tomoko Yoshino Masaaki Takahashi Harumi Ginya Junko Asahina Hideji Tajima Tadashi Matsunaga 《Applied microbiology》2008,74(16):5139-5145
Biotinylated magnetic nanoparticles were constructed by displaying biotin acceptor peptide (BAP) or biotin carboxyl carrier protein (BCCP) on the surface of bacterial magnetic particles (BacMPs) synthesized by Magnetospirillum magneticum AMB-1. BAP-displaying BacMPs (BAP-BacMPs) were extracted from bacterial cells and incubated with biotin and Escherichia coli biotin ligase. Then the in vitro biotinylation of BAP-BacMPs was confirmed using alkaline phosphatase-labeled antibiotin antibody. In contrast, BacMPs displaying the intact 149 residues of AMB-1 BCCP (BCCP-BacMPs) and displaying the COOH-terminal 78 residues of BCCP (BCCP78-BacMPs) were biotinylated in AMB-1 cells. The in vivo biotinylation of BCCP-BacMPs and BCCP78-BacMPs was thought to be performed by endogenous AMB-1 biotin ligase. Streptavidin was introduced onto biotinylated BacMPs by simple mixing. In an analysis using tetramethyl rhodamine isocyanate-labeled streptavidin, approximately 15 streptavidin molecules were shown to be immobilized on a single BCCP-BacMP. Furthermore, gold nanoparticle-BacMP composites were constructed via the biotin-streptavidin interaction. The conjugation system developed in this work provides a simple, low-cost method for producing biotin- or streptavidin-labeled magnetic nanoparticles. Various functional materials can be site selectively immobilized on these specially designed BacMPs. By combining the site-selective biotinylation technology and the protein display technology, more innovative and attractive magnetic nanomaterials can be constructed. 相似文献
88.
Flow cytometric analysis of circulating blood cells (hemocytes) of Biomphalaria glabrata, molluscan intermediate host of Schistosoma mansoni, revealed the presence of 2 overlapping hemocyte subpopulations, designated R1 and R2. R1 hemocytes are characterized by their smaller size, reduced granularity, and the presence of the BGH1 surface epitope, whereas R2 cells are larger, more granulated, and generally lack the BGH1 cell marker. Both hemocyte subpopulations bound fluorescent dye (Oregon Green)-conjugated excretory-secretory glycoproteins (fESPs), although the specific fESP binding signal (geometric mean value), after correction for cellular autofluorescence, was greater in the R1 hemocyte subpopulation compared to that of the R2 subset. Partial inhibition of fESP binding to hemocytes consistently was achieved using various glycoconjugates (mucin, asialo-mucin, asialo-fetuin, heparin) and polysaccharides (fucoidan, dextran sulfate 8000), suggesting the involvement of hemocyte carbohydrate-binding receptors (CBRs) in reactions with ESP-associated glycans. Although sulfation of carbohydrate ligands contributed significantly to ESP blocking activity of some inhibitory polysaccharides and heparin, other sulfated proteoglycans (chondroitins A and B, heparan sulfate) were noninhibitory, indicating that charge alone was not solely responsible for the observed inhibition of hemocyte binding by fESPs. A similar blocking effect by desialylated glycoproteins (asialo-mucin, asialo-fetuin) further supports the contention that ESP-hemocyte interactions are mediated primarily through CBRs. The glycoconjugate inhibitors of ESP binding were only partially effective over a range of concentrations and their glycan moieties (oligosaccharides or long-chain polymers) comprised a diversity of major sugar groups, suggesting that hemocyte CBRs and S. mansoni larval ESPs likely represent a multiple receptor-ligand system. Previously reported findings of differential effects of ESPs on a variety of in vitro hemocyte functions are consistent with such a hypothesis. 相似文献
89.
Boyle JP Yoshino TP 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2002,132(2):411-422
The potential role of selected biogenic monoamines and related compounds in the reproductive physiology of the freshwater snail Biomphalaria glabrata was investigated. Extracts of the albumen gland (AG), plasma, and central nervous system (CNS) were subjected to high pressure liquid chromatography with electrochemical detection (HPLC-ED), and under the extraction and separation conditions employed the following amines were detected: tyrosine, dihydroxyphenylalanine (DOPA), dopamine, and tryptophan in the AG; DOPA, tyrosine, and tryptophan in the plasma; DOPA, tyrosine, dopamine and 5-hydroxytryptamine in the CNS. These compounds were then quantified in individual samples taken from snails known to be in a particular stage of the egg-laying process. AG dopamine levels were highest in snails in the first stage of the reproductive process, when the AG is secreting perivitelline fluid around each fertilized ovum. Significant decreases in AG protein content during the later stages of the egg-laying process were also evident. Plasma tyrosine and DOPA levels were lowest in snails that contained a fully packaged egg mass, while no changes in monoamine content were observed in the CNS. These data provide insights into the role(s) that monoamines, especially catecholamine-related compounds, may play in B. glabrata reproductive physiology. 相似文献
90.