全文获取类型
收费全文 | 5702篇 |
免费 | 487篇 |
国内免费 | 1篇 |
出版年
2022年 | 33篇 |
2021年 | 90篇 |
2020年 | 48篇 |
2019年 | 58篇 |
2018年 | 75篇 |
2017年 | 51篇 |
2016年 | 131篇 |
2015年 | 197篇 |
2014年 | 253篇 |
2013年 | 355篇 |
2012年 | 376篇 |
2011年 | 373篇 |
2010年 | 270篇 |
2009年 | 231篇 |
2008年 | 335篇 |
2007年 | 354篇 |
2006年 | 320篇 |
2005年 | 302篇 |
2004年 | 321篇 |
2003年 | 291篇 |
2002年 | 278篇 |
2001年 | 75篇 |
2000年 | 71篇 |
1999年 | 80篇 |
1998年 | 119篇 |
1997年 | 64篇 |
1996年 | 68篇 |
1995年 | 55篇 |
1994年 | 51篇 |
1993年 | 59篇 |
1992年 | 58篇 |
1991年 | 43篇 |
1990年 | 29篇 |
1989年 | 40篇 |
1988年 | 38篇 |
1987年 | 21篇 |
1986年 | 16篇 |
1985年 | 27篇 |
1984年 | 27篇 |
1983年 | 25篇 |
1982年 | 37篇 |
1981年 | 33篇 |
1980年 | 31篇 |
1979年 | 24篇 |
1978年 | 24篇 |
1977年 | 20篇 |
1975年 | 17篇 |
1974年 | 18篇 |
1973年 | 18篇 |
1971年 | 25篇 |
排序方式: 共有6190条查询结果,搜索用时 15 毫秒
51.
The Role of Calcium Ions in the Acceleration of Resting Muscle Glycolysis by Extracellular Potassium
下载免费PDF全文
![点击此处可从《The Journal of general physiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The activation of the glycolysis of resting muscle by increased extracellular potassium is dependent upon the simultaneous presence of calcium, but not of sodium ions. This regulation of metabolism by a membrane characteristic seems to act upon an early link in the glycolytic enzyme chain. 相似文献
52.
53.
Summary and Conclusion 1. The germinating spores ofMicrosporon audouinii on infected hairs appear to require thiamine, riboflavin and nicotinic acid or its amide for initial growth. They show complete independence for inositol and pyridoxine.2. Components of the arginine-urea cycle and uracil stimulated growth more than other nitrogen sources. Organic nitrogen is more readily utilized than inorganic sources.3. The hexoses glucose, mannose and fructose are the better utilized carbohydrates. Trehalose is more stimulatory for growth than other disaccharides.4. Hydrogen ion optimum for growth is within a narrow range around pH 6.8 for buffered solutions. The optimum range is wider for unbuffered solutions under the conditions tested.5. Optimum temperature for growth lies within a narrow range of the normal variance of room temperature. Growth rate decreases rapidly at either extreme of this range.6. Within the limits of the system tested a positive Eh does not alter the growth rate or incubation time of the organism, but a negative initial redox potential decreases rate of growth and increases incubation time.A preliminary report of this work was presented at the 57th meeting of the Society of American Bacteriologists and was used in a graduate thesis by the senior author at the University of Illinois (24). 相似文献
54.
55.
56.
Study of the in vitro bioactivation of albendazole in human liver microsomes and hepatoma cell lines
Sylvie Rolin Hajar Souhaili-El Amri Anne-Marie Batt Michele Levy Denyse Bagrel Gerard Siest 《Cell biology and toxicology》1989,5(1):1-14
The metabolism of albendazole (ABZ), a benzimidazole anthelminthic, was studied in either microsomal preparations of human liver biopsies or cultured human hepatoma cell lines. Metabolites were analyzed by HPLC. Our data show that microsomes from human biopsies and two human cell lines, HepG2 and Hep3B, oxidize the drug to the sulfoxide very efficiently, whereas the third cell line tested, SK-HEP-1, does not. Both cytochrome P-450 dependent monooxygenases and favin-containing monooxygenases appear to be involved in human ABZ metabolism. Using the cell line displaying the highest ABZ-metabolizing activity, HepG2, the cytotoxic and the inducing effects of the parent drug ABZ and of two primary metabolites, the sulfoxide and the sulfone were studied. These three chemicals provoked a rise in mitotic index resulting from cell division blockage at the prophase or at the metaphase (ABZ metabolites) stage, and ABZ was more cytotoxic than its metabolites. With regard to enzyme-inducing effects, our data clearly demonstrate that the sulfoxide and, to a lesser degree, the sulfone are potent inducers of some drug metabolizing enzymes (i.e., cytochrome P-488 dependent monooxygenases and UDP glucuronyltransferase), whereas ABZ fails to increase and even slightly decreases these enzymatic activities. In conclusion, the HepG2 human hepatoma cell line appears to be suitable for the study of many parameters of metabolism and action of ABZ and other structurally related compounds in humans.Abbreviations ABZ
albendazole
- B[a]P
benzo[a]pyrene
- HPLC
high-performance liquid chromatography
- MC
3-methylcholanthrene
- MFO
mixed-function oxidase
- UDPGT
UDP-glucuronyltransferase 相似文献
57.
58.
Stefan Evers Barbara Casadewall Murielle Charles Sylvie Dutka-Malen Marc Galimand Patrice Courvalin 《Journal of molecular evolution》1996,42(6):706-712
Thed-alanine:d-alanine-ligase-related enzymes can have three preferential substrate specificities. Usually, these enzymes synthesized-alanyl-d-alanine. In vancomycin-resistant Gram-positive bacteria, structurally related enzymes synthesized-alanyl-d-lactate or Dalanyl-d-serine. The sequence of internal fragments of eight structurald-alanine:d-alanine ligase genes from enterococci has been determined. Alignment of the deduced amino acid sequences with those of other
related enzymes from Gram-negative and Gram-positive bacteria revealed the presence of four distinct sequence patterns in
the putative substrate-binding sites, each correlating with specificity to a particular substrate (d-alanine:d-lactate ligases exhibited two patterns). Phylogenetic analysis showed different clusters. The enterococcal subtree was largely
superimposable on that derived from 16S rRNA sequences. In lactic acid bacteria, structural divergence due to differences
in substrate specificity was observed. Glycopeptide resistance proteins VanA and VanB, the VanC-type ligases, and Dd1A and
DdlB from enteric bacteria andHaemophilus influenzae constituted separate clusters.
Correspondence to: P. Courvalin 相似文献
59.
60.