全文获取类型
收费全文 | 4046篇 |
免费 | 276篇 |
国内免费 | 165篇 |
出版年
2022年 | 31篇 |
2021年 | 63篇 |
2020年 | 33篇 |
2019年 | 63篇 |
2018年 | 53篇 |
2017年 | 63篇 |
2016年 | 82篇 |
2015年 | 119篇 |
2014年 | 151篇 |
2013年 | 217篇 |
2012年 | 230篇 |
2011年 | 250篇 |
2010年 | 144篇 |
2009年 | 149篇 |
2008年 | 228篇 |
2007年 | 193篇 |
2006年 | 186篇 |
2005年 | 180篇 |
2004年 | 172篇 |
2003年 | 173篇 |
2002年 | 154篇 |
2001年 | 150篇 |
2000年 | 139篇 |
1999年 | 107篇 |
1998年 | 54篇 |
1997年 | 42篇 |
1996年 | 52篇 |
1995年 | 43篇 |
1994年 | 36篇 |
1993年 | 38篇 |
1992年 | 83篇 |
1991年 | 85篇 |
1990年 | 78篇 |
1989年 | 56篇 |
1988年 | 57篇 |
1987年 | 53篇 |
1986年 | 41篇 |
1985年 | 29篇 |
1984年 | 46篇 |
1983年 | 27篇 |
1982年 | 27篇 |
1981年 | 25篇 |
1980年 | 19篇 |
1979年 | 30篇 |
1978年 | 21篇 |
1977年 | 22篇 |
1976年 | 25篇 |
1974年 | 25篇 |
1973年 | 21篇 |
1972年 | 22篇 |
排序方式: 共有4487条查询结果,搜索用时 15 毫秒
991.
Kunitake Hirashima Yataro Yoshida Shigetaka Asano Fumimaro Takaku Mitsuhiro Omine Shinpei Furusawa Tsukasa Abe Tatsuo Abe Hiroo Dohy Mitsuaki Tajiri Sumiya Eto 《Biotherapy》1991,3(4):297-307
Recombinant human granulocyte colony-stimulating factor (rhG-CSF) was investigated for its clinical efficacy in the treatment of various types of neutropenia (3 cases with idiopathic neutropenia of suspected drug induction, 5 cases with idiopathic neutropenia of other origin, and 2 cases with cyclic neutropenia). Treatment with glycosylated rhG-CSF produced in the Chinese Hamster Ovary cells at dose levels of 2–5g/kg/day caused rapid increases of neutrophil counts associated with an improvement of the infection. In cyclic neutropenia patients, marked reduction in the duration of the neutropenic period was observed with rhG-CSF administration started before the period. Intercurrent stomatitis, which occurred in 1 patient, was markedly milder as compared to a previous episode which occurred during an untreated neutropenic period.The treatment of rhG-CSF was well tolerated and no adverse events were observed, nor was there any detectable anti-rhG-CSF antibody in any patients studied; hence the clinical use of rhG-CSF is considered to be safe.These results suggest beneficial effects of rhG-CSF on the recovery of neutrophil counts in cyclic and other types of idiopathic neutropenias, as well as for the treatment of neutropenia-associated infection. 相似文献
992.
H Tsunoda S Katayama Y Sakuma S Tanaka K Tsukidate S Abe I Yamatsu K Katayama 《Prostaglandins, leukotrienes, and essential fatty acids》1991,42(1):51-56
6-Hydroxy-2-(4-sulfamoylbenzylamino)-4,5,7-trimethylbenzothiazo le hydrochloride (E6080), an orally active and selective 5-lipoxygenase inhibitor, dose-dependently inhibited the bronchospasm induced by antigen (ovalbumin) inhalation in sensitized conscious guinea pigs. The inhibitory effect of E6080 was more potent than that of a typical 5-lipoxygenase inhibitor, AA861, but less than that of a leukotriene (LT) antagonist, LY171883. When airway infiltration of neutrophils and eosinophils was measured in bronchoalveolar lavage fluid (BALF) at 6 h after antigen inhalation by passively sensitized guinea pigs, the inhibitory effect of E6080 on neutrophil infiltration was more marked than that on eosinophil infiltration. The inhibitory effect of E6080 on bronchoalveolar cellular infiltration and bronchoepithelial damage was confirmed by examination of photomicrographs of the lung. In addition to the above pharmacological effects, E6080 inhibited the increase in BALF levels of both i-LTC4 and i-LTB4. These results suggest that E6080 may prove to be effective for the treatment of asthma, in which large amounts of leukotrienes (LTs) are elaborated. 相似文献
993.
994.
F. Uematsu H. Kikuchi T. Abe M. Motomiya T. Ohmachi I. Sagami M. Watanabe 《Nucleic acids research》1991,19(20):5797
995.
Bacteriophage-induced acidic heteropolysaccharide lyases that convert the acidic heteropolysaccharides of Rhizobium trifolii into oligosaccharide units 总被引:11,自引:6,他引:5
下载免费PDF全文
![点击此处可从《Journal of bacteriology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Acidic heteropolysaccharide lyases from lysates of phages 4S and BY15 grown on Rhizobium trifolii 4S and R. trifolii 0403, respectively, were used to analyze the capsular and excreted extracellular acidic polysaccharides of R. trifolii 0403. The activities of the enzymes as measured by viscometry were enhanced by the addition of calcium. The oligosaccharide products obtained by depolymerase digestion of the polysaccharides isolated from cells grown on agar plates for 5 days were isolated by gel filtration and had a glycosyl composition of glucose, galactose, glucuronic acid, and alpha-linked 4-deoxy-L-threo-hex-4-enopyranosyluronic acid in an approximate molar ratio of 5:1:1:1. This latter component was identified by 1H-nuclear magnetic resonance spectroscopy and confirmed by UV spectroscopy, ozonolysis, and its reactivity with thiobarbituric acid. The oligosaccharide had glucose as the reducing terminus, 4-deoxy-L-threo-hex-4-enopyranosyluronic acid as the enzymatically generated nonreducing terminus, and galactose as the terminus of the branched chain. The noncarbohydrate components of the oligosaccharides were acetate, ketal-linked pyruvate, and ether-linked 3-hydroxybutyrate. The mode of action of the enzymes was by beta-elimination from a uronic acid residue with concomitant loss of the glycosyl component substituted at C-4. The 235-nm absorbing properties of the resulting terminal unsaturated sugar were used to study the kinetics of depolymerization of the capsular and excreted extracellular acidic polysaccharides, using the enzyme from phage BY15. The two substrates exhibited different kinetics of depolymerization, and the oligosaccharide products differed in the amount of noncarbohydrate substituents, indicating that the acidic capsular and excreted extracellular polysaccharides from 5-day-old cultures of R. trifolii 0403 were different. 相似文献
996.
Two forms of cytochrome b5, a soluble erythrocyte form and a membrane-bound liver form, were purified from pig and human, and structural differences between them were analyzed. Porcine and human erythrocyte cytochrome b5 consisted of 97 amino acid residues and contained the same catalytic domain structure (residues 1-96) as that of the corresponding liver cytochrome b5, but had one amino acid replacement at the C-terminus (residue 97). These results suggest that erythrocyte cytochrome b5 is not derived from the liver protein by proteolysis but a translational product from another distinct mRNA of cytochrome b5. 相似文献
997.
The complete amino acid sequence (72 amino acid residues) of a double-headed proteinase inhibitor from seeds of Vicia angustifolia L. var. segetalis Koch has been determined and compared with those of other double-headed inhibitors of known structure. Sequencing was performed by conventional methods with the aid of the fragments produced by reduction and S-carboxymethylation of the enzymatically modified inhibitors, and also using tryptic and chymotryptic peptides. The positions of the 14 half-cystine residues agreed among all the reported primary structures of the legume double-headed inhibitors. However, V. angustifolia inhibitor possessed extensive amino acid differences compared to the others. The phylogenetic relationship among these inhibitors was established using the unweighted pair-group method and revealed that the V. angustifolia inhibitor and the peanut inhibitor B-III had diverged at a relatively earlier stage compared to the other inhibitors. 相似文献
998.
In an attempt to evaluate effects of bacterial endotoxin on systemic fungal infection, experimental systemic Aspergillus infection was induced in leukemic mice (AKR strain) with (Group B) or without (Group A) preceding intraperitoneal administration of Pseudomonas aeruginosa derived lipopolysaccharides. All mice in group A died within 4 days after intravenous inoculation of Aspergillus fumigatus spores and developed extensive and disseminated fungal lesions without inflammatory reactions. In contrast, 5 of 10 mice in group B were alive at day 4 and 1 mouse in group B was alive when the experiment was terminated on the 14th day. These mice showed less extensive fungal lesions with definite, albeit minimal, inflammatory reactions which were composed of macrophages and neutrophils. In addition, serum iron levels and iron saturation rates were significantly lower in mice in group B than in group A. These results indicate that P. aeruginosa endotoxin has a deterring effect on systemic Aspergillus infection in leukemic mice. 相似文献
999.
S Abe S Makimura K Itabashi Y Kawakami 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1987,9(6):495-498
The relationship between the cytomorphologic features, the nuclear DNA patterns and the clinical prognosis of patients with small cell carcinoma of the lung was studied. In cases in the long-survival group (greater than or equal to 24 months), bronchial brushing smears contained a relatively high frequency of nuclei with large, irregular shapes and finely granular chromatin patterns, in comparison with patients in the short-survival group (less than or equal to 9 months); the correlation was not statistically significant, however. The incidence of cells with round or oval nuclei and finely granular chromatin patterns was higher in patients whose cells had hyperdiploid DNA patterns than for patients whose cells had near-diploid patterns; again, the difference was not statistically significant. Patients whose tumor cells had hyperdiploid DNA patterns had significantly shorter survival times than did patients whose tumor cells had near-diploid patterns. These results indicate that (1) judging the nuclear DNA pattern from the cytomorphologic features of small cell carcinoma is unreliable and (2) the nuclear DNA patterns are related to the clinical prognosis of patients with small cell carcinoma of the lung. 相似文献
1000.
Protein kinase C phosphorylation of protamine is Ca2+ independent, but the addition of DNA renders it Ca2+ dependent 总被引:1,自引:0,他引:1
Protamine is a unique substrate of protein kinase C for its Ca2+-independent phosphorylation. The interaction between protein kinase C and protamine and the effect of DNA on the interaction was studied. Protein kinase C was retained in a protamine-immobilized Sepharose 4B column, even in the absence of Ca2+ and was eluted with ammonium sulfate or L-arginine. The eluted enzyme was fully activated by phosphatidylserine alone, when protamine was used as substrate. When DNA was included in the assay system, the activity elicited by phosphatidylserine alone was inhibited. The DNA effect on the activity in the presence of both Ca2+ and phosphatidylserine was much lower than on the activity elicited by phosphatidylserine alone, thereby demonstrating the Ca2+ sensitivity of protamine phosphorylation. 相似文献