全文获取类型
收费全文 | 1165篇 |
免费 | 66篇 |
国内免费 | 1篇 |
专业分类
1232篇 |
出版年
2019年 | 10篇 |
2018年 | 24篇 |
2017年 | 28篇 |
2016年 | 20篇 |
2015年 | 40篇 |
2014年 | 51篇 |
2013年 | 68篇 |
2012年 | 66篇 |
2011年 | 64篇 |
2010年 | 43篇 |
2009年 | 25篇 |
2008年 | 38篇 |
2007年 | 56篇 |
2006年 | 44篇 |
2005年 | 47篇 |
2004年 | 43篇 |
2003年 | 51篇 |
2002年 | 34篇 |
2001年 | 23篇 |
2000年 | 28篇 |
1999年 | 19篇 |
1998年 | 13篇 |
1996年 | 12篇 |
1993年 | 10篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 20篇 |
1989年 | 17篇 |
1988年 | 18篇 |
1987年 | 17篇 |
1986年 | 19篇 |
1985年 | 18篇 |
1984年 | 25篇 |
1983年 | 13篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 14篇 |
1978年 | 11篇 |
1977年 | 10篇 |
1976年 | 10篇 |
1975年 | 12篇 |
1974年 | 7篇 |
1973年 | 12篇 |
1971年 | 11篇 |
1970年 | 9篇 |
1969年 | 7篇 |
1968年 | 11篇 |
1967年 | 8篇 |
1966年 | 12篇 |
排序方式: 共有1232条查询结果,搜索用时 7 毫秒
31.
32.
33.
34.
Trébouet Florian Malaivijitnond Suchinda Reichard Ulrich H. 《Primates; journal of primatology》2021,62(3):491-505
Primates - Macaque reproductive patterns range from strictly seasonal breeding to non-seasonal breeding, but factors explaining this variation are not fully understood. Valid reproductive... 相似文献
35.
Tr Heinz 《Biotechnic & histochemistry》2013,88(5-6):211-222
Scientific investigations depend on the reliability of the observations that can be made. This reliability is determined in part by the understanding of the techniques and technology used to make the observations. The limitations and the strengths of the methodology and the equipment used must be evaluated thoroughly. The extent to which this is and has been the case for the use of the metal based stains in neuroscience is the subject of this paper. I evaluate the metallic stains used for neuroscience from several perspectives. I review briefly the state of neurohistology prior to its “golden years,” 1870–1910. Then I trace the development of the silver based stains used for neurohistology. I wanted to discuss the reasoning used by the originators of the silver based techniques in developing their specific procedures, but discovered that while procedures may be published, the methods and ideas used to arrive at the final procedures are not usually described in published work. 相似文献
36.
E. Trévisiol E. Defrancq J. Lhomme A. Laayoun A. Hoang F. Besème 《Nucleosides, nucleotides & nucleic acids》2013,32(4-5):979-980
Abstract We report a novel strategy for Post-Amplification Labelling based upon coupling nucleotide incorporating an oxyamino function with a fluorophore bearing an aldehydic group. 相似文献
37.
38.
Hans G. Trüper 《Geomicrobiology journal》2013,30(4):373-374
Abstract Laboratory simulations have helped resolve several problems concerning the role of bacteria in producing acidic drainage from active and abandoned coal mines. It is well established that the bacterium Thiobacillus ferrooxidans oxidizes pyrite in synthetic liquid media and in flooded or agitated experimental simulations of coal mine environments. However, many geologists remain skeptical regarding the role of T. ferrooxidans in producing acidity below a near‐surface belt of soil water. We have demonstrated that T. ferrooxidans is capable of colonizing and acidifying a near‐neutral pH environment of crushed coal or overburden, without prior establishment of a pH‐dependent succession of bacteria. We have suggested that T. ferrooxidans may accomplish this by direct oxidation of pyrite. We have also shown that T. ferrooxidans catalyzes pyrite oxidation in the intermediate belt of the zone of aeration, although only for a limited period of time after rainfall infiltration. T. ferrooxidans was not found to be significant in the simulated zone of groundwater saturation. 相似文献
39.
Johannes F. Imhoff Hans G. Sahl Gaber S.H. Soliman Hans G. Trüper 《Geomicrobiology journal》2013,30(3):219-234
Six lakes of the Wadi Natrun, Egypt, were studied with respect to the chemical composition of their brines and the occurrence of microbial mass developments. All investigated lakes showed pH values of approximately 11 and a total salt content of generally more than 30%. The main components were sulfate, carbonate, chloride, sodium, and minor amounts of potassium. Only traces of magnesium and calcium were present, but unusually high concentrations of organic carbon compounds, nitrogen compounds, and phosphate were found. Mass developments of phototrophic sulfur bacteria, halobacteria, cyanobacteria, and green algae were observed. The functions of complete nitrogen and sulfur cycles in the alkaline brines are discussed. The properties of the lakes and their ecology are compared with data on the Dead Sea and Great Salt Lake, Utah. 相似文献
40.
A membrane-bound, pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenase (ADH) was purified from Frateuria aurantia LMG 1558T. Although F. aurantia belongs to a group of γ-Proteobacteria, the characteristics of its PQQ-ADH were similar to the enzyme characteristics of the typical high-acetic acid-resistant bacterium Gluconacetobacter europaeus from the group of α-Proteobacteria. The PQQ-dependent ADH was solubilized from the membranes and purified after anionic, cationic, and affinity chromatography with specific activity of 117 U/mg. The purified enzyme was estimated to be composed of two subunits of ca. 72 and 45 kDa, as judged by SDS-polyacrylamide gel electrophoresis. The purified enzyme had maximum activity at pH 4.5 and showed the highest substrate specificity to ethanol, isoamyl alcohol, 1-butanol, and 1-propanol. The deduced sequences of cloned genes adhA and adhB encoding subunits I and II of PQQ-ADH showed 80 % amino acid (AA) identity to AdhA and 68 % AA identity to AdhB of Ga. europaeus V3 (LMG 18494). Because of the high similarity between genes encoding subunits I and II of PQQ-ADH and its homologous genes found in a distantly related taxonomic group of acetic acid bacteria, the results suggest the possibility of horizontal gene transfer between these two groups of genera. 相似文献