全文获取类型
收费全文 | 2579篇 |
免费 | 153篇 |
国内免费 | 9篇 |
出版年
2023年 | 30篇 |
2022年 | 60篇 |
2021年 | 112篇 |
2020年 | 85篇 |
2019年 | 128篇 |
2018年 | 125篇 |
2017年 | 90篇 |
2016年 | 103篇 |
2015年 | 111篇 |
2014年 | 161篇 |
2013年 | 205篇 |
2012年 | 226篇 |
2011年 | 188篇 |
2010年 | 103篇 |
2009年 | 94篇 |
2008年 | 115篇 |
2007年 | 127篇 |
2006年 | 91篇 |
2005年 | 76篇 |
2004年 | 62篇 |
2003年 | 77篇 |
2002年 | 61篇 |
2001年 | 24篇 |
2000年 | 29篇 |
1999年 | 19篇 |
1998年 | 17篇 |
1997年 | 16篇 |
1996年 | 12篇 |
1995年 | 7篇 |
1994年 | 12篇 |
1993年 | 6篇 |
1992年 | 13篇 |
1991年 | 10篇 |
1990年 | 11篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 9篇 |
1986年 | 10篇 |
1984年 | 7篇 |
1983年 | 13篇 |
1982年 | 10篇 |
1981年 | 13篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 5篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有2741条查询结果,搜索用时 15 毫秒
91.
Yaghoub Yazdani Neda Keyhanvar Hamid Reza Kalhor Abbas Rezaei 《Biotechnology letters》2013,35(8):1191-1197
Hepcidin is a peptide hormone that plays an important role in iron metabolism. We have produced a recombinant mouse hepcidin-1 by using baculovirus expression system. Its expression yield was 25 μg/ml when cell culture media were supplemented with a protease inhibitor cocktail. The recombinant mouse hepcidin-1 and synthetic human hepcidin-25 had similar effects on reducing ferroportin expression in J774A cell line and in peritoneal macrophages. However, synthetic human hepcidin-25 was more efficient than recombinant mouse hepcidin-1 in reducing iron concentration in blood circulation (p < 0.01). 相似文献
92.
Seyedeh Zahra Mousavi Sepideh Amjad-Iranagh Yousef Nademi Hamid Modarress 《The Journal of membrane biology》2013,246(9):697-704
Understanding the penetration mechanisms of carbon nanotube (CNTs)-encapsulated drugs through the phospholipid bilayer cell membrane is an important issue for the development of intracellular drug delivery systems. In the present work, steered molecular dynamics (SMD) simulation was used to explore the possibility of penetration of a polar drug, paclitaxel (PTX), encapsulated inside the CNT, through a dipalmitoylphosphatidylcholine bilayer membrane. The interactions between PTX and CNT and between PTX and the confined water molecules inside the CNT had a significant effect on the penetration process of PTX. The results reveal that the presence of a PTX molecule increases the magnitude of the pulling force. The effect of pulling velocity on the penetration mechanism was also investigated by a series of SMD simulations, and it is shown that the pulling velocity had a significant effect on pulling force and the interaction between lipid bilayer and drug molecule. 相似文献
93.
Rashid Nazir Jan A. Warmink David C. Voordes Henk H. van de Bovenkamp Jan Dirk van Elsas 《Microbial ecology》2013,65(1):245-254
We investigated the ecological strategies exerted by the soil bacterium Burkholderia terrae BS001 at the hyphae of the soil saprotrophic fungus Lyophyllum sp. strain Karsten. Recently, this bacterium has been reported to form biofilms around, and to comigrate with, growing hyphae of Lyophyllum sp. strain Karsten. In addition, it was found to be able to utilize fungal metabolites. Here, we extend this work to shed some light on the interactions between the bacterial and fungal partner which allow ecological success for the former. In standing liquid microcosms inoculated with Lyophyllum sp. strain Karsten, we detected, upon prolonged incubation, the formation of a mycelial mat at the liquid–air interface. From this mat, primordia were formed after 4–6 weeks, which eventually resulted in mushrooms. However, upon addition of strain BS001 to the bulk liquid, mushroom formation from the fungal mat was clearly inhibited, as evidenced by (1) the formation of significantly lower numbers of primordia and (2) a delay of the onset of primordia formation. Moreover and importantly, the presence of strain BS001 caused the fungus to secrete large amounts of exudates at the mycelial mat, whereas such exudation was absent from control (uninoculated) or Escherichia coli K12- or Variovorax paradoxus BS64-inoculated microcosms. In the exudates, glycerol was the main carbonaceous component, and this compound could be easily utilized by strain BS001. Thus, in different experimental set-ups with the fungal partner, strain BS001 was shown to grow in the fungal exudates on the mat. The two fungal-interactive phenotypes were specific for B. terrae strain BS001, as the other bacteria used in our study, i.e. E. coli K12 and V. paradoxus BS64, did not exhibit any of these phenomena. 相似文献
94.
95.
Mahboob Ahmad Malik M. Ahmad Rifat Hamid M. Z. Abdin Saleem Javed 《Mycotoxin Research》2013,29(1):39-45
Aflatoxins are one of the most important secondary metabolites. These extrolites are produced by a number of Aspergillus fungi. In this study, we demonstrate the effect of media components and enhanced aflatoxin yield shown by A. flavus using response surface methodology in response to different nutrients. Different components of a chemically defined media that influence the aflatoxin production were monitored using Plackett–Burman experimental design and further optimized by Box–Behnken factorial design of response surface methodology in liquid culture. Interactions were studied with five variables, namely sorbitol, fructose, ammonium sulfate, KH2PO4, and MgSO4.7H2O. Maximum aflatoxin production was envisaged in medium containing 4.94 g/l sorbitol, 5.56 g/l fructose, 0.62 g/l ammonium sulfate, 1.33 g/l KH2PO4, and 0.65 g/l MgSO4·7H2O using response surface plots and the point prediction tool of the DESIGN EXPERT 8.1.0 (Stat-Ease, USA) software. However, a production of 5.25 μg/ml aflatoxin production was obtained, which was in agreement with the prediction observed in verification experiment. The other component (MgSO4.7H2O) was found to be an insignificant variable. 相似文献
96.
Maïlys Chassagne-Manoukian Hamid Haddoumi Henri Cappetta André Charrière Monique Feist Rodolphe Tabuce Monique Vianey-Liaud 《Geobios》2013,46(5):371-379
A new locality in the poorly known “red beds” of Tendrara (High Plateaus, Morocco) has yielded four charophytes species (Feistiella anluensis, Lamprothamnium stipitatum, Peckisphaera portezueloensis, Platychara caudata) and dinosaur eggshells (Pseudomegaloolithus atlasi). These red beds, which overly the Cenomanian-Turonian marine deposits, generally assigned to “Senonian” based on geometric position, are directly dated by these fossils: the charophytes species and dinosaur oospecies association indicates a Campano-Maastrichtian or Maastrichtian age for these calm floodplain deposits. 相似文献
97.
Hamid Manzoor Jani Kelloniemi Annick Chiltz David Wendehenne Alain Pugin Benoit Poinssot Angela Garcia‐Brugger 《The Plant journal : for cell and molecular biology》2013,76(3):466-480
Like their animal counterparts, plant glutamate receptor‐like (GLR) homologs are intimately associated with Ca2+ influx through plasma membrane and participate in various physiological processes. In pathogen‐associated molecular patterns (PAMP)‐/elicitor‐mediated resistance, Ca2+ fluxes are necessary for activating downstream signaling events related to plant defense. In this study, oligogalacturonides (OGs), which are endogenous elicitors derived from cell wall degradation, were used to investigate the role of Arabidopsis GLRs in defense signaling. Pharmacological investigations indicated that GLRs are partly involved in free cytosolic [Ca2+] ([Ca2+]cyt) variations, nitric oxide (NO) production, reactive oxygen species (ROS) production and expression of defense‐related genes by OGs. In addition, wild‐type Col‐0 plants treated with the glutamate‐receptor antagonist 6,7‐dinitriquinoxaline‐2,3‐dione (DNQX) had a compromised resistance to Botrytis cinerea and Hyaloperonospora arabidopsidis. Moreover, we provide genetic evidence that AtGLR3.3 is a key component of resistance against H. arabidopsidis. In addition, some OGs‐triggered immune events such as defense gene expression, NO and ROS production are also to different extents dependent on AtGLR3.3. Taken together, these data provide evidence for the involvement of GLRs in elicitor/pathogen‐mediated plant defense signaling pathways in Arabidopsis thaliana. 相似文献
98.
Objectives
Donor specific antibodies (DSA) and a positive cross‐match are contraindications for kidney transplantation. Trials of allograft transplantation across the HLA barrier have employed desensitization strategies, including the use of plasmapheresis, intravenous immunoglobulins, anti‐B‐cell monoclonal antibodies and splenectomy, associated with high‐intensity immunosuppressive regimens. Our case 1 report suffered from repeatedly positive lymphocyte cross match after 1st renal transplantation. Graft nephrectomy could not correct the state of sensitization. Splenectomy was done in a trial to get rid of the antibody producing clone. Furthermore plasmapheresis with low dose IVIG could not as well revert the state of sensitization for the patient.Material and methods
About 50 millions donor specific MSCs were injected to the patient.Results
MSCs transfusion proved to be the only procedure which could achieve successful desensitization before performing the second transplantation owing to their immunosuppressive properties.Conclusion
This case indicates that DS‐MSCs is a potential option for anti‐HLA desensitization. In cases 2 and 3 IV DS‐MSCs transfusion was selected from the start as a successful line of treatment for pre renal transplantation desensitization to save other unnecessary lines of treatment that were tried in case 1.99.
Mikhail V. Pugachev Nikita V. Shtyrlin Lubov P. Sysoeva Elena V. Nikitina Timur I. Abdullin Alfiya G. Iksanova Alina A. Ilaeva Rashid Z. Musin Eugeny A. Berdnikov Yurii G. Shtyrlin 《Bioorganic & medicinal chemistry》2013,21(14):4388-4395
A series of 13 phosphonium salts on the basis of pyridoxine derivatives were synthesized and their antibacterial activity against clinically relevant strains was tested in vitro. All compounds were almost inactive against gram-negative bacteria and exhibited structure-dependent activity against gram-positive bacteria. A crucial role of ketal protection group in phosphonium salts for their antibacterial properties was demonstrated. Among synthesized compounds 5,6-bis[triphenylphosphonio(methyl)]-2,2,8-trimethyl-4H-[1,3]dioxino[4,5-c]pyridine dichloride (compound 20) was found to be the most effective towards Staphylococcus aureus and Staphylococcus epidermidis strains (MIC 5 μg/ml). The mechanism of antibacterial activity of this compound probably involves cell penetration and interaction with genomic and plasmid DNA. 相似文献
100.
Hamid Forootanfar Mojtaba Shakibaie Zahra Bagherzadeh Marzieh Aghaie-Khozani Nastaran Nafissi-Varcheh Hamid Reza Monsef-Esfahani Mohammad Ali Faramarzi 《Journal of applied phycology》2013,25(1):51-57
The present study aimed at evaluating the ability of some isolated cyanobacterial and microalgal strains for the removal of ρ-chlorophenol (ρ-CP), an environmentally harmful contaminant. To identify the most efficient species, a screening program was carried out using 15 microalgal and cyanobacterial strains. Among them, Tetraselmis suecica was able to remove 67 % of the ρ-chlorophenol at an initial concentration of 20 mg L?1 from the medium within a 10-day period. The efficacy of the process was dependent on the ρ-chlorophenol concentration. At concentrations above 60 mg L?1 of the pollutant, no removal was observed due to the inhibitory effect of ρ-chlorophenol on the T. suecica cells. The effect of cell immobilization in alginate beads on T. suecica removal capacity was also examined. Using this technique, the removal efficacy for the initial ρ-CP concentration of 20 mg L?1 increased up to 94 %. 相似文献