全文获取类型
收费全文 | 1119篇 |
免费 | 41篇 |
出版年
2022年 | 16篇 |
2021年 | 26篇 |
2020年 | 20篇 |
2019年 | 18篇 |
2018年 | 41篇 |
2017年 | 36篇 |
2016年 | 37篇 |
2015年 | 34篇 |
2014年 | 51篇 |
2013年 | 47篇 |
2012年 | 61篇 |
2011年 | 54篇 |
2010年 | 47篇 |
2009年 | 42篇 |
2008年 | 41篇 |
2007年 | 51篇 |
2006年 | 47篇 |
2005年 | 33篇 |
2004年 | 45篇 |
2003年 | 41篇 |
2002年 | 32篇 |
2001年 | 27篇 |
2000年 | 19篇 |
1999年 | 13篇 |
1998年 | 7篇 |
1997年 | 6篇 |
1995年 | 6篇 |
1992年 | 12篇 |
1991年 | 16篇 |
1990年 | 17篇 |
1989年 | 5篇 |
1988年 | 8篇 |
1987年 | 10篇 |
1986年 | 17篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 10篇 |
1979年 | 8篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 9篇 |
1974年 | 15篇 |
1973年 | 11篇 |
1972年 | 14篇 |
1971年 | 13篇 |
1970年 | 14篇 |
1969年 | 11篇 |
1968年 | 4篇 |
1967年 | 8篇 |
1966年 | 7篇 |
排序方式: 共有1160条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
M A Petrova 《Biulleten' eksperimental'no? biologii i meditsiny》1985,100(11):583-584
Alcohol dehydrogenase (ADH) activity was determined by a highly sensitive method. The enzyme activity in the blood serum was similar in alcohol and water preferring rats, while ADH activity in the liver of alcohol preferring rats was higher than in water preferring rats. In rats, chronically intoxicated with ethanol, ADH activity in the liver decreased, while in the serum it was twice higher than the normal level. It is suggested that high level of blood ADH is not connected with the rate of enzyme synthesis in the liver. 相似文献
5.
Blidingia minima var. ramifera is reported for the first time in eastern North America. It occurs in the Gulf of St. Lawrence, Nova Scotia and in Maine. In the estuary of the West and Rights Rivers (Antigonish Harbour, Nova Scotia) it is the most common intertidal alga and during its maximum growth period (June-August) covers 75–90% of the intertidal zone for several km of shoreline at the mouth of the Rights River. In culture, spore germination and early development were typical of the taxon as described from Europe. The taxon is raised to specific status as Blidingia ramifera stat. nov. Blidingia subsalsa is confirmed from New England based on observations of spore germination in plants from Maine and Connecticut. 相似文献
6.
Dynamics of development of the cerebral cortex tissue anlage in 17-day-old embryos of Wistar rats, implanted into the sciatic nerve of mature rats with the aim to establish new relay and trophic centers in the regenerating nerve have been studied. By means of certain morphological methods (silver nitrate impregnation after Bielschowsky-Gros, Sudan black, hematoxylin-eosin, toluidine blue after Nissl stainings) it has been stated that the implanted nerve cells not only preserve their viability, but also differentiate from neuroblasts up to young and mature neurons during 2 months. Already in 14 days after the operation there are blood vessels in the implants; by the 2d month massive myelinization of axons begins in the implant. A part of the regenerating myelin fibers of the nerve gets into the implant and branches. In similar cases connections between the implanted neurons and the host peripheral nervous fibers are supposed to be established. 相似文献
7.
Thomas F. Holzman Christine C. Chung Rohinton Edalji David A. Egan Earl J. Gubbins Annemarie Rueter Gail Howard Lana K. Yang Terry M. Pederson Grant A. Krafft et al. 《Journal of Protein Chemistry》1990,9(6):663-672
The gene for human preprorenin was obtained from total RNA prepared from primary human chorion cells. An expression vector was constructed containing an SV40 early promoter, a human preprorenin cDNA, bovine growth hormone poly-A addition signal, and a dihydrofolate reductase (dhfr) expression cassette. This vector was inserted into the DXB-11 Chinese hamster ovary (CHO) cell line. The recombinant protein was exported by CHO cells into the tissue culture media. At harvest the prorenin levels ranged from 1–5 mg/L. For prorenin isolation the cell culture supernatants were processed by filtration, concentration, dialysis, and batch extraction. Preparative-scale isolation of prorenin was accomplished using blue-dye chromatography and size-exclusion chromatography. The isolated prorenin yielded a single SDS-gel band with Mr 40,000. The proprotein was characterized with respect to N-terminal sequence and N-linked sugar composition. Trypsin-activated renin prepared from the proprotein was characterized with respect to N-terminal sequence andpH-activity profile. Enzyme activity was measured with a newly developed fluorogenic peptide substrate containing the P6-P3 sequence of human angiotensinogen. 相似文献
8.
T A Petrova O V Shamova S N Lyzlova 《Zhurnal evoliutsionno? biokhimii i fiziologii》1988,24(4):489-496
Electrophoretic studies have been made of the protein composition and isozymic pattern of the creatine kinase from muscles of the cod. It was shown that this enzyme constitutes up to 40% of total water-soluble proteins of muscle tissue. Isolation and purification procedures were suggested for the creatine kinase from cod muscles which allow to obtain the enzyme with the specific activity 250-350 IU/mg. Comparative enzymic analysis of creatine kinases from muscle tissue of the cod, lake frog, and rabbit was also made. Studies were carried out on temperature dependence of the reaction, kinetic constants at temperatures 5 and 30 degrees C were determined together with other physicochemical properties of the enzymes. The revealed species specific differences are discussed in relation to the structure and function of the enzymes in lower vertebrates in vivo. 相似文献
9.
M S Petrova R G Shakirova N A Antonova G N Feoktistova 《Antibiotiki i khimioterapii͡a》1992,37(11):40-43
The data accumulated within the last years required revision of the indications to the use of antibiotics in treatment of pertussis. One of the aims of antibiotic therapy in pertussis was to prevent colonization of B. pertussis in the respiratory tracts. With that end in view the choice of antibiotics should be limited by those, to which the pathogen is the most sensitive i.e. erythromycin, ampicillin and augmentin. Comparative efficacy of erythromycin and ampicillin during the first 2 weeks of the disease was studied in 79 infants at the age not older than 1 year with pertussis and it was shown that erythromycin was advantageous by its therapeutic activity and less side effects. Expedience of the antibiotic therapy during the spastic period for providing a preventive effect on development of bronchopulmonary complications was studied in 201 patients with pertussis. No preventive effect of the antibiotics on development of the bronchopulmonary complications defined by the secondary bacterial flora was recorded. In the group of the patients treated with the antibiotics prophylactically (group 1) the complications were 2.6 times more frequent than in the patients treated with pathogenetic agents alone (group 2). Intrahospital pneumonia developed in 8.9 per cent of the patients in group 1 and in 1.5 per cent of the patients in group 2. Therefore, antibiotics should not be used at the late periods of pertussis for prophylaxis of secondary bacterial complications. 相似文献
10.
Augmentin is a new combination manufactured by Smith Kline Beecham (Great Britain). It is composed of amoxycillin and clavulanic acid and has antibacterial activity. Augmentin was used in clinical trials in the therapy of 50 adult patients with suppurations after surgical operations on the organs of the abdominal cavity, general staphylococcal infections, pneumonia and prophylactically during the preoperative period. It was also used in the treatment of 30 children patients with bronchopulmonary affections and inflammatory otorhinolaryngological diseases. The clinical trials were performed in the Clinic of Infectious Diseases of the N. G. Gabrichevski? Moscow Research Institute of Epidemiology and Microbiology. For comparison ampicillin was used in the trials. Augmentin was shown to be an efficient formulation with antibacterial activity which could be successfully used in the parenteral therapy of severe affections due to organisms sensitive to it. In the treatment of the children patients with pneumonia augmentin by its therapeutic efficacy proved to be superior to ampicillin. The tolerance of augmentin was good. 相似文献