全文获取类型
收费全文 | 570篇 |
免费 | 22篇 |
出版年
2021年 | 8篇 |
2020年 | 7篇 |
2018年 | 9篇 |
2017年 | 16篇 |
2016年 | 13篇 |
2015年 | 10篇 |
2014年 | 12篇 |
2013年 | 12篇 |
2012年 | 19篇 |
2011年 | 17篇 |
2010年 | 13篇 |
2009年 | 13篇 |
2008年 | 12篇 |
2007年 | 26篇 |
2006年 | 23篇 |
2005年 | 21篇 |
2004年 | 18篇 |
2003年 | 18篇 |
2002年 | 15篇 |
2001年 | 11篇 |
2000年 | 14篇 |
1999年 | 9篇 |
1998年 | 5篇 |
1992年 | 11篇 |
1991年 | 17篇 |
1990年 | 13篇 |
1989年 | 10篇 |
1988年 | 16篇 |
1987年 | 9篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1983年 | 7篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 9篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 8篇 |
1974年 | 4篇 |
1973年 | 9篇 |
1972年 | 11篇 |
1971年 | 4篇 |
1970年 | 6篇 |
1969年 | 7篇 |
1968年 | 8篇 |
1966年 | 10篇 |
1965年 | 6篇 |
1958年 | 5篇 |
1957年 | 4篇 |
排序方式: 共有592条查询结果,搜索用时 15 毫秒
1.
Seasonal dynamics and demographic structure was studied in 15 dominant ground beetle species in the mountain taiga and mountain forest-steppe belts of the Eastern Sayan (Okinskoe Plateau). Life cycles of the dominant ground beetle species were classified by developmental time, seasonal dynamics, and intrapopulation groups with different reproduction timing. The strategies of carabid life cycles adapted to severe mountain conditions of the Eastern Sayan were revealed. 相似文献
2.
Tihomir Todorov Albena Todorova Bilyana Georgieva Vanyo Mitev 《Molecular biotechnology》2010,45(2):150-154
We report on a unified rapid betaine-based-PCR protocol for amplification of the (CAG)n region in Huntington disease (HD) and the (CGG)n region in Fragile X syndrome (FXS), followed by an electrophoretic separation on automated sequencer for precise determination
of the triplet numbers. The high betaine concentration (2.5 M betaine) permits precise amplification of the CAG and CGG repeats.
Ten HD affected patients and 10 healthy individuals from HD families were re-evaluated. For FXS the CGG region in normal individuals
and premutations of about 100 repeats were precisely amplified by this protocol. Ten unrelated FXS premutation carriers and
24 mentally retarded non-FXS affected boys were re-examined by this method. The results totally coincided with the previous
ones. This protocol is a good choice as a fast screening test. Within 24 h we can have preliminary information on the patient’s
genetic status. Normal individuals, CGG premutation carriers up to 100 repeats, as well as HD patients carrying an expansion
up to 50 CAG repeats can be easily clarified. This accounts for a relatively large proportion (about 90%) of the suspected
HD and FXS patients, referred to our laboratory for genetic analysis. The calculation of the repeat’s number is more accurate
for the correct interpretation of the results, screening tests and genetic counselling. 相似文献
3.
4.
E A Serbinova R A Bakalova Ts S Sto?chev V E Kagan 《Biulleten' eksperimental'no? biologii i meditsiny》1986,102(10):419-421
The efficacy of lipid peroxidation inhibition by the natural antioxidant alpha-tocopherol and 2,2,5,7,8-pentamethyl-6-hydroxy-chromane (PMC), a derivative without hydrocarbon tail, as well as by the synthetic antioxidant 4-methyl-2,6-diterbutyl phenol (BHT) and its phospholipid derivative was studied in the membranes of rat liver microsomes and mitochondria. The presence of hydrocarbon tail in the antioxidant molecule determines the decrease of antioxidant efficiency in biomembranes. PMC and BHT exert a destructive effect on biomembranes, leading to an increase in their permeability to ions. This evidence suggests that the presence of hydrocarbon tail in the molecules of natural antioxidants provides not only for a relatively high antioxidant efficiency but also for a structural stability of biomembranes. 相似文献
5.
The effect of helium-neon laser radiation (lambda = 633 nm) given to E. coli K-12 cells of various genotypes 4 h following X- or alpha-irradiation was shown to increase the number of viable cells. The irreversible ingradient of a radiation injury to cells remained invariable during the first 60 min after irradiation its values being minimal. 相似文献
6.
I E Gurski? Ts V Serbeniuk P Ia Romanovski? 《Zhurnal evoliutsionno? biokhimii i fiziologii》1988,24(4):545-550
It has been shown that thyroliberin and its synthetic analogue PR-546 injected into the lymphatic sacs (4.10(-7)-4.10(-9) g/kg) or applied to the medulla oblongata in the bulbar frogs (4.10(-10)-4.10(-12) g/kg) significantly increase the rate of motor respiratory volleys in the hypoglossal nerve. In preparations with the irregular level of the activity of the respiratory center, these drugs enhanced stabilization of the initial level of the rhythm of motor respiratory discharges. 相似文献
7.
B J Keats A A Todorov L D Atwood M Z Pelias J F Hejtmancik W J Kimberling M Leppert R A Lewis R J Smith 《Genomics》1992,14(3):707-714
Usher Syndrome Type 1 is an autosomal recessive disease characterized by profound congenital hearing impairement and vestibular dysfunction followed by the onset of retinitis pigmentosa in childhood or early adolescence. Members of the Usher Syndrome Consortium, whose objective is to locate and isolate the genes for Usher syndrome, have pooled linkage data from 36 families with 111 affected individuals. We report the analysis of 206 blood group, protein, and DNA marker polymorphisms. No evidence of linkage heterogeneity among families was found for any of the markers studied; the negative lod scores exclude the locus for this disease from about 39% of the genome. Our results indicate the regions of the genome to which our continuing efforts should be directed. 相似文献
8.
I M A?vazashvili Ts A Ordzhonikidze 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》1985,35(1):32-38
Direct and indirect methods of delayed reactions showed that short-term image memory of rats elaborated on the basis of conditioned signals in poorly developed and its duration is not more than 1 s. While testing this memory, changes in the behaviour were seen, pointing to the development of "hard state" in the higher nervous activity of animals. Short-term image memory based on complex perception was shown to be well developed in rats, and by many characteristics it approximated to the memory of highly organized animals. The ability to reproduce the short-term image memory on the basis of conditioned signals is supposed to be a complex form of psychonervous activity of animals, and in rodents it appears to be at an initial stage of development. 相似文献
9.
10.