全文获取类型
收费全文 | 1446篇 |
免费 | 67篇 |
国内免费 | 1篇 |
专业分类
1514篇 |
出版年
2023年 | 22篇 |
2022年 | 31篇 |
2021年 | 60篇 |
2020年 | 39篇 |
2019年 | 27篇 |
2018年 | 46篇 |
2017年 | 36篇 |
2016年 | 50篇 |
2015年 | 61篇 |
2014年 | 77篇 |
2013年 | 129篇 |
2012年 | 118篇 |
2011年 | 104篇 |
2010年 | 60篇 |
2009年 | 50篇 |
2008年 | 68篇 |
2007年 | 63篇 |
2006年 | 55篇 |
2005年 | 47篇 |
2004年 | 46篇 |
2003年 | 45篇 |
2002年 | 32篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 18篇 |
1998年 | 12篇 |
1997年 | 11篇 |
1996年 | 11篇 |
1995年 | 5篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 9篇 |
1988年 | 8篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1984年 | 8篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1979年 | 7篇 |
1977年 | 8篇 |
1976年 | 3篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1971年 | 5篇 |
1970年 | 4篇 |
1969年 | 5篇 |
1966年 | 3篇 |
排序方式: 共有1514条查询结果,搜索用时 0 毫秒
31.
32.
33.
34.
35.
This study was performed to determine the effects of levamisole and levamisole + vitamin C against Syphacia muris naturally infection in rats and to detect its effect on the oxidative parameters in blood and tissues of host. For this purpose, natural infection was diagnosed using the cellophane tape method on the perianal region of rats. Infected rats (total 18) were divided into three groups. On the other hand six without helminth rats were used in this study as negative control group. Group 2 was given an orally levamisole HCl treatment with gastric gavage at a dose level of 20 mg/kg body weight in distilled water, every alternate day. Group 3 was given levamisole HCl via gastric gavage at a dose level of 20 mg/kg and vitamin C was given 1 g/L added to the drinking water. All the treatments continued for a period of 7 days. As a result; levamisole administered to rats at dose of 20 mg/kg orally 98.34% was found to be effective against adult S. muris in the rats. In addition to levamisole + vitamin C is effective to alleviate the oxidative damage in rats infected with S. muris. 相似文献
36.
Zvi Peleg Ismail Cakmak Levent Ozturk Atilla Yazici Yan Jun Hikmet Budak Abraham B. Korol Tzion Fahima Yehoshua Saranga 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,119(2):353-369
Mineral nutrient malnutrition, and particularly deficiency in zinc and iron, afflicts over 3 billion people worldwide. Wild
emmer wheat, Triticum turgidum ssp. dicoccoides, genepool harbors a rich allelic repertoire for mineral nutrients in the grain. The genetic and physiological basis of grain
protein, micronutrients (zinc, iron, copper and manganese) and macronutrients (calcium, magnesium, potassium, phosphorus and
sulfur) concentration was studied in tetraploid wheat population of 152 recombinant inbred lines (RILs), derived from a cross
between durum wheat (cv. Langdon) and wild emmer (accession G18-16). Wide genetic variation was found among the RILs for all grain minerals, with
considerable transgressive effect. A total of 82 QTLs were mapped for 10 minerals with LOD score range of 3.2–16.7. Most QTLs
were in favor of the wild allele (50 QTLs). Fourteen pairs of QTLs for the same trait were mapped to seemingly homoeologous
positions, reflecting synteny between the A and B genomes. Significant positive correlation was found between grain protein
concentration (GPC), Zn, Fe and Cu, which was supported by significant overlap between the respective QTLs, suggesting common
physiological and/or genetic factors controlling the concentrations of these mineral nutrients. Few genomic regions (chromosomes
2A, 5A, 6B and 7A) were found to harbor clusters of QTLs for GPC and other nutrients. These identified QTLs may facilitate
the use of wild alleles for improving grain nutritional quality of elite wheat cultivars, especially in terms of protein,
Zn and Fe. 相似文献
37.
Ulviye Acar Çevik Ismail Celik Ufuk İnce Zahra Maryam Iqrar Ahmad Harun Patel Yusuf Özkay Zafer Asım Kaplancıklı 《化学与生物多样性》2023,20(3):e202201146
In this work, the synthesis, characterization, and biological activities of a new series of 1,3,4-thiadiazole derivatives were investigated. The structures of final compounds were identified using 1H-NMR, 13C-NMR, elemental analysis, and HRMS. All the new synthesized compounds were then screened for their antimicrobial activity against four types of pathogenic bacteria and one fungal strain, by application of the MIC assays, using Ampicilin, Gentamycin, Vancomycin, and Fluconazole as standards. Among the compounds, the MIC values of 4 and 8 μg/mL of the compounds 3f and 3g , respectively, are remarkable and indicate that these compounds are good candidates for antifungal activity. The docking experiments were used to identify the binding forms of produced ligands with sterol 14-demethylase to acquire insight into relevant proteins. The MD performed about 100 ns simulations to validate selected compounds’ theoretical studies. Finally, using density functional theory (DFT) to predict reactivity, the chemical characteristics and quantum factors of synthesized compounds were computed. These results were then correlated with the experimental data. Furthermore, computational estimation was performed to predict the ADME properties of the most active compound 3f . 相似文献
38.
Ismail AB Yoshinobu T Iwasaki H Sugihara H Yukimasa T Hirata I Iwata H 《Biosensors & bioelectronics》2003,18(12):1509-1514
This article reports an investigation on light-addressable potentiometric sensor (LAPS) to be used as a possible biological cell-semiconductor hybrid that will enable us to make an interface between the physical and biological system. To increase the surface potential sensitivity, we used a LAPS structure with single insulator (SiO2) coated with poly-L-ornithine and laminin (PLOL) on Si. Efficient culturing of PC-12 and nerve cells of Lymnaea stagnalis on PLOL-coated Si3N4 and SiO2 was achieved. The thickness of the PLOL layer was found to be about 4 nm by the atomic force microscope (AFM) measurement. Using the advantage of this thin layer of PLOL, we compared the performance of a novel structure to the previously reported "PLOL-coated Si3N4/SiO2/Si" structure. Due to high insulating capacitance, the photocurrent response of the novel LAPS was found to be very steep. As a result, higher sensitivity was achieved. This steepness did not degrade during 10 days when the sensor surface was kept in contact with the cell culture medium and environment. The thickness of PLOL layer, its ability to improve the biological cell adhesion, enhanced sensitivity, and experiment with simulated neural action potential (AP) applied to the novel LAPS show a good promise for LAPS to be a biological cell-semiconductor hybrid. 相似文献
39.
Pyrenophora teres f. teres (Ptt) causes net form net blotch disease of barley, partially by producing necrosis‐inducing proteins. The protein profiles of the culture filtrates of 28 virulent isolates were compared by a combination of 2DE and 1D‐PAGE with 105 spots and 51 bands chosen for analysis by liquid chromatography electrospray ionization tandem mass spectrometry. A total of 259 individual proteins were identified with 63 of these proteins being common to the selected virulent isolates. Ptt secretes a broad spectrum of proteins including cell wall degrading enzymes; virulence factors and effectors; proteins associated with fungal pathogenesis and development; and proteins related to oxidation–reduction processes. Potential virulence factors and effectors identified included proteins with glucosidase activity, ricin B and concanavalin A‐like lectins, glucanases, spherulin, cutinase, pectin lyase, leucine‐rich repeat protein, and ceratoplatanin. Small proteins with unknown function but cysteine‐rich, common to effectors, were also identified. Differences in the secretion profile of the Ptt isolates have also provided important insight into the different mechanisms contributing to virulence and the development of net form net blotch symptoms. 相似文献
40.
Ismail Abdou Guy G. Poirier Michael J. Hendzel Michael Weinfeld 《Nucleic acids research》2015,43(2):875-892
In the current model of DNA SSBR, PARP1 is regarded as the sensor of single-strand breaks (SSBs). However, biochemical studies have implicated LIG3 as another possible SSB sensor. Using a laser micro-irradiation protocol that predominantly generates SSBs, we were able to demonstrate that PARP1 is dispensable for the accumulation of different single-strand break repair (SSBR) proteins at sites of DNA damage in live cells. Furthermore, we show in live cells for the first time that LIG3 plays a role in mediating the accumulation of the SSBR proteins XRCC1 and PNKP at sites of DNA damage. Importantly, the accumulation of LIG3 at sites of DNA damage did not require the BRCT domain-mediated interaction with XRCC1. We were able to show that the N-terminal ZnF domain of LIG3 plays a key role in the enzyme''s SSB sensing function. Finally, we provide cellular evidence that LIG3 and not PARP1 acts as the sensor for DNA damage caused by the topoisomerase I inhibitor, irinotecan. Our results support the existence of a second damage-sensing mechanism in SSBR involving the detection of nicks in the genome by LIG3. 相似文献