全文获取类型
收费全文 | 8678篇 |
免费 | 570篇 |
国内免费 | 6篇 |
出版年
2022年 | 36篇 |
2021年 | 111篇 |
2020年 | 55篇 |
2019年 | 86篇 |
2018年 | 103篇 |
2017年 | 104篇 |
2016年 | 166篇 |
2015年 | 258篇 |
2014年 | 305篇 |
2013年 | 563篇 |
2012年 | 454篇 |
2011年 | 494篇 |
2010年 | 265篇 |
2009年 | 268篇 |
2008年 | 457篇 |
2007年 | 448篇 |
2006年 | 458篇 |
2005年 | 472篇 |
2004年 | 459篇 |
2003年 | 411篇 |
2002年 | 383篇 |
2001年 | 242篇 |
2000年 | 242篇 |
1999年 | 215篇 |
1998年 | 111篇 |
1997年 | 89篇 |
1996年 | 84篇 |
1995年 | 86篇 |
1994年 | 96篇 |
1993年 | 94篇 |
1992年 | 156篇 |
1991年 | 124篇 |
1990年 | 132篇 |
1989年 | 149篇 |
1988年 | 103篇 |
1987年 | 115篇 |
1986年 | 93篇 |
1985年 | 102篇 |
1984年 | 85篇 |
1983年 | 67篇 |
1982年 | 46篇 |
1981年 | 45篇 |
1980年 | 33篇 |
1979年 | 53篇 |
1978年 | 35篇 |
1977年 | 41篇 |
1976年 | 29篇 |
1975年 | 25篇 |
1974年 | 32篇 |
1973年 | 24篇 |
排序方式: 共有9254条查询结果,搜索用时 531 毫秒
181.
Tadashi II Masayuki Kubota Takashi Hirano Mamoru Ohashi Keiichi Yoshida Sakaru Suzuki 《Glycoconjugate journal》1995,12(3):282-289
The fast atom bombardment (FAB) collision induced dissociation (CID)-mass spectrometry/mass spectrometry (MS/MS) technique was successfully applied to characterize and identify the structures of the immunoreactive trisulfated and tetrasulfated tetrasaccharides that were obtained from the chondroitin sulfate in a shark fin using a treatment with chondroitinase ABC.Abbreviations FABMS
fast atom bombardment mass spectrometry
- CID
collision induced dissociation
- MS/MS
mass spectrometry/mass spectrometry
- UA2S-GalNAc6S
2-acetamido-2-deoxy-3-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-galactose
- UA-GalNAc4S
2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-4-O-sulfo-d-galactose
- UA-GalNAcDiS
2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-4,6-di-O-sulfo-d-galactose 相似文献
182.
Koichiro Suzuki Kenji Kanazawa Kyoko Higuchi Naoko K. Nishizawa Satoshi Mori 《Biometals》1997,10(2):77-84
In a previous paper we reported that an acidic 36 kDa peptide is the most strongly induced peptide among several peptides induced by Fe deficiency in barley roots. In this paper, polyclonal antibodies were raised against the 36 kDa peptide. This peptide appeared in the roots of all the graminaceous species tested (barley, rye, wheat, oat, maize, sorghum and rice) in response to Fe deficiency. More of the peptide was found in the roots of graminaceous species which secrete higher amounts of mugineic acids (MAs) under Fe deficient nutrition status. Induction of the 36 kDa peptide was first observed on the third day of Fe deficiency, rising to a maximum value on the seventh day. The trend has a positive correlation with secretion of MAs during Fe deficiency. Further, resupply of Fe resulted in a decrease in peptide production on the second day, reaching a control level on the seventh day. The rate of decrease in peptide production was observed to be slower than that of MA secretion. Other nutrient stresses such as B excess, B deficiency, Cu excess, Cu deficiency, Mn excess, Mn deficiency, Zn excess and Zn deficiency induced far less of the peptide. The specific expression of the 36 kDa peptide in roots of graminaceous species under Fe deficiency suggested the positive association of the peptide with a specific Fe deficiency tolerance mechanism in graminaceous plants. 相似文献
183.
Masayuki Kobayashi Marc Garcia-Elias Ladislav Nagy Marco J. P. F. Ritt Kai-Nan An William P. Cooney Ronald L. Linscheid 《Journal of biomechanics》1997,30(11-12)
The changes in carpal bone alignment secondary to the aplication of an axial compressive load through the major wrist motor tendons while the wrist is kept in neutral position (isometric loading) have been investigated on 13 fresh cadaver specimens using a biplanar radiographic method of kinematic analysis. The scaphoid, lunate and triquetrum rotate an average of 5.1, 4.2 and 3.8°, respectively, around different ‘screw displacement axes’, all implying flexion, radial deviation and supination. Based on these findings, a new interpretation of the mechanism by which the wrist remains stable under physiologic loads is provided. 相似文献
184.
Kohei Murata Masato Sakon Jun-ichi Kambayashi Masaki Okuyama Toshiharu Hase Takesada Mori 《Journal of cellular biochemistry》1995,57(1):120-126
Calyculin A and okadaic acid, potent and cell permeable inhibitors of type 1 and type 2A protein phosphatases, inhibit platelet aggregation and secretion. However, the relationship between phosphatase inhibition and inhibition of platelet function is not well understood. We found that in unstimulated platelets, talin (P235) was phosphorylated at threonine residues by calyculin A. Furthermore, the extent of talin phosphorylation by calyculin A was closely correlated with its inhibition of thrombin-induced platelet aggregation. Since the binding of talin to platelet glycoprotein IIb/IIIa complex has been shown to be affected by its phosphorylation, these results suggest that type 1 and/or type 2A protein phosphatases may play a role in the regulation of membrane-cytoskeleton interaction through dephosphorylation of talin. 相似文献
185.
Yasushi Isashiki Norio Ohba Toyoko Yanagita Naoko Hokita Norihito Doi Masanori Nakagawa Masayuki Ozawa Noriko Kuroda 《Human genetics》1995,95(1):105-108
We have identified a new mutation of Norrie disease (ND) gene in two Japanese males from unrelated families; they showed typical ocular features of ND but no mental retardation or hearing impairment. A mutation was found in both patients at the initation codon of exon 2 of the ND gene (ATG to GTG), with otherwise normal nucleotide sequences. Their mothers had the normal and mutant types of the gene, which was expected for heterozygotes of the disease. The mutation of the initiation codon would cause the failure of ND gene expression or a defect in translation thereby truncating the amino terminus of ND protein. In view of the rarity and marked heterogeneity of mutations in the ND gene, the present apparently unrelated Japanese families who have lived in the same area for over two centuries presumably share the origin of the mutation. 相似文献
186.
Post-ischemic administration of the acetylcholinesterase inhibitor ENA-713 prevents delayed neuronal death in the gerbil hippocampus 总被引:3,自引:0,他引:3
We examined by morphological methodology the effect of (S)-N-ethyl-3-[(1-dimethyl-amino)ethyl]-N-methyl-phenylcarbamate hydrogentartrate (ENA-713), an acetylcholinesterase (AChE) inhibitor, on ischemia-induced neuronal death in the gerbil hippocampus due to a 5-min ligation of bilateral common carotid arteries after light ether anesthesia. Pyramidal cells had been decreased to 27% of sham-operated controls and the number of hypertrophic astrocytes expressing glial fibrillary acidic protein (GFAP) markedly increased in the hippocampal CA1 subfield 14 days after ischemia. However, post-ischemic administration of ENA-713 (three times 0.2 mg/kg, i.p.) significantly ameliorated this ischemia-induced decrease in the number of pyramidal cells by 47% of sham-operated controls, furthermore, it reduced the ischemia-induced accumulation of GFAP-positive astrocyte in the CA1 region. Together with previous results showing that ENA-713 protected against the ischemia-induced cholinergic abnormalities in the gerbil brain and improved cholinergic dysfunctions in the senescent rat brain, our present findings suggest that ENA-713 prove to be useful for treatment with senile dementia such as cerebrovascular dementia. 相似文献
187.
Immunochemical characterisation and epitope mapping of a novel fimbrial protein (Pg-II fimbria) of Porphyromonas gingivalis 总被引:2,自引:0,他引:2
Tomohiko Ogawa Kenji Yasuda Keiko Yamada Hideharu Mori Keiko Ochiai Mamoru Hasegawa 《FEMS immunology and medical microbiology》1995,11(3):247-255
Abstract Mouse monoclonal antibody (mAb) Pgf-II specific for a 72-kDa major cell-surface protein (72K-CSP) derived from Porphyromonas gingivalis OMZ 409 was prepared. Immunoblotting analysis revealed that mAb Pgf-II reacted with 72K-CSP but not with 41-kDa fimbrial subunit protein (41K-fimbrilin) derived from P. gingivalis 381. Electron microscopic observation revealed that P. gingivalis OMZ 409 possessed peritrichous, thin fimbriae on their surface. Immunogold electron microscopy also demonstrated that mAb Pgf-II bound to the 72K-CSP examined with the gold particles arranged along the fibril array originating from the cell surface of the bacteria. These findings suggested that P. gingivalis 72K-CSP was identifiable as another fimbriae (termed Pg-II fimbriae) different from the fimbriae (termed Pg-I fimbriae) composed of a 41K-fimbrilin. Using multipin peptide synthesis technology, 102 sequential overlapping peptides covering the entire 514 amino-acid stretch of Pg-II fimbriae were synthesised. Seven immunodominant regions within Pg-II fimbrial protein molecule, which definitely reacted with the serum of patients with periodontal diseases, were detected. 相似文献
188.
189.
190.
Toda Hideshige; Takahashi Masayuki; Ichimura Shun-ei 《Journal of plankton research》1984,6(4):647-662
The effect of temperature on post-embryonic growth of Neomysisintermedia was investigated under unlimited food conditionsin the laboratory. The effect of temperature on the size ofnewly released animals was negligibly small, but body size wasinversely related to temperature in adults. This was mainlycaused by the difference in the number of molts before maturation.The specific growth rate of N. intermedia increased exponentiallywith a temperature coefficient, Q10 of 4.6 from 0.018 d13C to 0.21 d1 at 20C in juveniles, and with a temperaturecoefficient of 2.7 from 0.006 d1 at 3C to 0.05 d1at 25C in adults. The rate in juveniles levelled off above20C, and dropped at 29C. Brood size and brood interval decreasedwith temperature increase, while the daily specific reproductionrate increased. The specific growth rate of gravid females,including production of egg matter, increased exponentiallywith a temperature coefficient of 3.3 from 0.015 d1 at10C to 0.093 d1 at 25C. The present laboratory experiments confirmed the temperaturecontrol on the growth of N. intermedia suggested in a hyper-eutrophiclake. 相似文献