全文获取类型
收费全文 | 1535篇 |
免费 | 29篇 |
国内免费 | 1篇 |
出版年
2016年 | 11篇 |
2013年 | 38篇 |
2012年 | 47篇 |
2011年 | 67篇 |
2010年 | 82篇 |
2009年 | 59篇 |
2008年 | 70篇 |
2007年 | 79篇 |
2006年 | 58篇 |
2005年 | 60篇 |
2004年 | 28篇 |
2003年 | 26篇 |
2002年 | 7篇 |
2001年 | 15篇 |
2000年 | 10篇 |
1999年 | 19篇 |
1998年 | 28篇 |
1997年 | 47篇 |
1996年 | 35篇 |
1995年 | 34篇 |
1994年 | 28篇 |
1993年 | 20篇 |
1992年 | 40篇 |
1991年 | 34篇 |
1990年 | 34篇 |
1989年 | 29篇 |
1988年 | 26篇 |
1987年 | 21篇 |
1986年 | 16篇 |
1985年 | 22篇 |
1984年 | 13篇 |
1983年 | 17篇 |
1982年 | 26篇 |
1981年 | 14篇 |
1980年 | 30篇 |
1979年 | 19篇 |
1978年 | 20篇 |
1977年 | 19篇 |
1976年 | 19篇 |
1975年 | 20篇 |
1974年 | 21篇 |
1973年 | 23篇 |
1972年 | 37篇 |
1971年 | 42篇 |
1969年 | 8篇 |
1965年 | 7篇 |
1959年 | 7篇 |
1958年 | 11篇 |
1957年 | 8篇 |
1952年 | 13篇 |
排序方式: 共有1565条查询结果,搜索用时 31 毫秒
71.
72.
PAUL R. FITZGERALD 《The Journal of eukaryotic microbiology》1965,12(2):215-221
SYNOPSIS. Five experiments using newborn Holstein-Friesian and weaner Hereford calves were conducted to observe the effects caused by parenteral injections of oocysts of Eimeria bovis . Sporulated oocysts were given intraperitoneally (IP), subcutaneously (SC), intramuscularly (IM) and intravenously (IV). Unsporulated oocysts or merozoites were given IP or IM.
Coccidiosis developed in calves in three experiments after they were inoculated IP with sporulated oocysts. Immunity to reinfection resulted from these infections. No infections occurred at any time after SC, IM or IV inoculation with sporulated oocysts or after IP or IM inoculation with unsporulated oocysts or merozoites.
Coccidiosis failed to occur in two experiments when special precautions were used to prevent puncture of the intestines during IP inoculations. There was no detectable immunological response to any of the inoculations unless intestinal infections occurred.
In one experiment sporulated oocysts were exposed to 60,000 r irradiation by x-ray in an attempt to attenuate the oocysts. Calves became infected when given orally administered oocysts irradiated at this level. 相似文献
Coccidiosis developed in calves in three experiments after they were inoculated IP with sporulated oocysts. Immunity to reinfection resulted from these infections. No infections occurred at any time after SC, IM or IV inoculation with sporulated oocysts or after IP or IM inoculation with unsporulated oocysts or merozoites.
Coccidiosis failed to occur in two experiments when special precautions were used to prevent puncture of the intestines during IP inoculations. There was no detectable immunological response to any of the inoculations unless intestinal infections occurred.
In one experiment sporulated oocysts were exposed to 60,000 r irradiation by x-ray in an attempt to attenuate the oocysts. Calves became infected when given orally administered oocysts irradiated at this level. 相似文献
73.
74.
PAUL ADAM 《Austral ecology》2013,38(5):e1-e1
75.
RITA COLÓN-URBAN PAUL J. CHEUNG GEORGE D. RUGGIERI ROSS F. NIGRELLI 《Invertebrate reproduction & development.》2013,57(4):245-252
Thirty-two pedunculate barnacles, O. a. geryonophila, were maintained in culture for a period of 2 yr in the laboratory. These barnacles were obtained from the pleopods and mouth parts of the giant marine isopod, Bathynomus giganteus, which had been collected, at a depth of 200 fathoms, in the Gulf of Mexico. The carina, scutum, mandible and maxilla of adult barnacles were typical of deep water species. However, the tergum and labrum were intermediate between those of shallow and deep water species. Adults 3.1–4.1 mm in length were cultured in sea water (15–19°C), and fed on benthic copepods such as Tisbe furcata and Laophonte sp. Three broods of nauplii from 8 barnacles were obtained in 2 yr. Larvae were reared on plankton collected from Coney Island waters in which nauplii reached Stage IV in 10–14 days at 16°C. Isochrysis galbana and Thalassiosira pseudonana individually or in combination maintained nauplii to Stage IV, but with very high mortality. The lack of spines on the carapace edge of the nauplii distinguishes this deep water species from the shallow water form, O. mulleri. 相似文献
76.
ALEXANDRA HOUSSAYE JEAN‐CLAUDE RAGE NATHALIE BARDET PEGGY VINCENT MBAREK AMAGHZAZ SAID MESLOUH 《Palaeontology》2013,56(3):647-661
Abstract: Palaeophis maghrebianus belongs to the Palaeophiinae (Palaeophiidae). This snake subfamily is relatively poorly known, and it is mainly represented by disarticulated vertebrae and ribs and by a few vertebral segments. Its intracolumnar variability remains also poorly understood. The discovery of new isolated vertebrae and vertebral segments of Palaeophis maghrebianus in the Ypresian (Lower Eocene) Phosphates of Morocco enables us to provide a more detailed diagnosis of this species and to describe its intracolumnar variability. Moreover, the new material reveals that this species could reach gigantic size being, with Palaeophis colossaeus, one of the two longer palaeophiids. The microanatomical and histological analysis of some vertebrae illustrating diverse positions along the vertebral column reveals the presence of osteosclerosis, especially in the anterior and mid‐precloacal regions. The occurrence of this osseous specialization implies a role in buoyancy and body trim control in this taxon, which is considered a shallow marine dweller based on its anatomical features and geological data. Palaeophis maghrebianus also displays a dense vascular network suggesting a growth speed, and thus a metabolic rate, much higher than in the biggest extant snakes. 相似文献
77.
78.
JUDITH DESOUTTER CHRISTELE OSSART MARIE-NOËLLE LACASSAGNE ALINE REGNIER JEAN PIERRE MAROLLEAU VERONIQUE HARRIVEL 《Cytotherapy》2019,21(6):612-618
IntroductionCell damage inescapably occurs during both the freezing and the thawing graft processes for autologous hematopoietic stem cell (HSC) transplantation. To estimate HSC injury, a quality control is performed including: (i) CD34+ quantification; (ii) percentage of CD34+ viability and (iii) evaluation of HSC functional ability to form colony forming unit–granulocyte macrophage (CFU-GM). Apoptosis involves complex pathways such as caspase enzymes. Here, we assess the extent of apoptosis that is caspase-dependent before and after cryoconservation of CD34+, using a Fluorescent Labeled Inhibitor of CAspases (FLICA).MethodsCaspase pathway activation status was evaluated in 46 patients (multiple myeloma [n = 24], lymphoma [n = 22]), by flow cytometry, using a 7-aminoactinomycin-D (7AAD)/FLICA staining test, in CD34+, CD3+, CD14+ and CD56+ cells. Viable 7AAD?/FLICA+ cells were then correlated with various parameters.ResultsWe showed a significant caspase pathway activation, with 23% CD34+/7AAD?/FLICA+ cells after thawing, compared with the 2% described in fresh CD34+ cells (P < 0.0001). Moreover, caspase pathway was significantly activated in thawing CD3+, CD56+ and CD14+ cells. We also report a significant correlation between the rate of CD34+/7AAD?/FLICA+ cells and post-thawing granulocytes count (P = 0.042) and their potential to be differentiated into CFU-GM (P = 0.004).DiscussionOur results show substantial cell death, induced by the increase of caspase pathway activation, secondary to the thawing process, and across all study cell types. This observation may affect the immune response quality during recipient aplasia, without detecting a clinical impact. Moreover, caspase pathway activation through CD3+ and CD56+ subpopulations could modify the therapeutic result of donor lymphocytes infusion (DLI). 相似文献
79.
RADKA POLKOV MARTINA VYSKOILOV JEAN‐FRANOIS MARTIN HERMAN L. MAYS GEOFFREY E. HILL JOSEF BRYJA TOM ALBRECHT 《Molecular ecology resources》2007,7(6):1375-1378
Cardueline finches have become important models in studies of sexual selection and evolution of carotenoid‐based ornamentation. Here, we describe eight new polymorphic microsatellites isolated from the Scarlet rosefinch (Carpodacus erythrinus) and four from the House finch (Carpodacus mexicanus). Together with the cross‐species amplification of additional loci, originally published for two species of songbirds, we optimized a multiplex panel for C. erythrinus allowing genotyping of 22 polymorphic loci. Number of alleles and heterozygosity per locus in a sample of 34 individuals ranged from three to 38 and from 0.27 to 0.94, respectively. 相似文献
80.
PAUL EGGLETON ROBERT BELSHAW 《Biological journal of the Linnean Society. Linnean Society of London》1993,48(3):213-226
We consider differences between dipteran, hymenopteran and coleopteran parasitoids in the following categories: taxonomic range and developmental stage of hosts attacked; habitats they are attacked in; developmental stage of the parasitoid contacting the host; occurrence of phoresy, and attacking hosts during flight. Using existing phylogenetic classifications we reconstruct possible ancestral conditions to the parasitoid clades in the three orders. By considering these as phylogenetic constraints and potentialities we attempt to account for the observed differences between the parasitoids within the orders. 相似文献