全文获取类型
收费全文 | 391篇 |
免费 | 27篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 8篇 |
2016年 | 14篇 |
2015年 | 21篇 |
2014年 | 21篇 |
2013年 | 20篇 |
2012年 | 28篇 |
2011年 | 37篇 |
2010年 | 18篇 |
2009年 | 22篇 |
2008年 | 19篇 |
2007年 | 26篇 |
2006年 | 28篇 |
2005年 | 19篇 |
2004年 | 23篇 |
2003年 | 16篇 |
2002年 | 10篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1970年 | 2篇 |
排序方式: 共有418条查询结果,搜索用时 15 毫秒
131.
Slavica Ninković Jovanka Miljuš-Đukić Svetlana Radović Vesna Maksimović Jelica Lazarević Branka Vinterhalter Mirjana Nešković Ann Smigocki 《Plant Cell, Tissue and Organ Culture》2007,91(3):289-294
Phytodecta fornicata Brüggemann is a serious pest of alfalfa (Medicago
sativa L.) that causes significant crop loss in the Balkan peninsula of Europe. We introduced a wound-inducible oryzacystatin II
(OCII) gene to alfalfa to evaluate its effect on survival of P. fornicata larvae. Feeding bioassays with second, third and fourth instars were carried out using transgenic plants that were shown
to express OCII at 24 and 48 h after wounding. Second and third instars were the most sensitive to the ingestion of OCII,
whereas no effects were observed with fourth instars. About 80% of the second and third instars died after 2 days of feeding
on the transgenic plants as compared to 0–40% on the controls. This is the first report that demonstrates significant increase
in mortality of P. fornicata on transgenic plants that express a cysteine proteinase inhibitor gene, and this knowledge should lead to the development
of effective management strategies for this devastating pest of alfalfa. 相似文献
132.
Zippelius A Gati A Bartnick T Walton S Odermatt B Jaeger E Dummer R Urosevic M Filonenko V Osanai K Moch H Chen YT Old LJ Knuth A Jaeger D 《Cancer immunology, immunotherapy : CII》2007,56(2):249-258
Expression pattern and immunogenicity are critical issues that define tumor antigens as diagnostic markers and potential targets for immunotherapy. The development of SEREX (serological analysis of recombinant expression libraries) has provided substantial progress in the identification of tumor antigens eliciting both cellular and humoral immune responses in cancer patients. By SEREX, we have previously identified RAB38/NY-MEL-1 as a melanocyte differentiation antigen that is highly expressed in normal melanocytes and melanoma tissues but not in other normal tissues or cancer types. In this study, we further demonstrate that RAB38/NY-MEL-1 is strongly immunogenic, leading to spontaneous antibody responses in a significant proportion of melanoma patients. The immune response occurs solely in malignant melanoma patients and was not detected in patients with other diseases, such as vitiligo, affecting melanocytes. Fine analysis of the spontaneous anti-RAB38/NY-MEL-1 antibody response reveals a polyclonal B cell recognition targeting various epitopes, although a dominant immunogenic region was preferentially recognized. Interestingly, our data indicate that this recognition is not rigid in the course of a patient’s response, as the dominant epitope changes during the disease evolution. Implications for the understanding of spontaneous humoral immune responses are discussed.Alfred Zippelius and Asma Gati contributed equally to this work. 相似文献
133.
Erceg M Kujundzić-Tiljak M Babić-Erceg A Coric T Lang S 《Collegium antropologicum》2007,31(3):891-895
The aim of the study was to establish whether the physicians' strike, which took place in Croatia in 2003, had an impact on the mortality of the population. Mortality data from the National Bureau of Statistics relating to the strike period (15 January - 14 February 2003) were selected and compared with the previous and subsequent periods of the same duration in 2001, 2002 and 2004. Of the 52,575 deaths in 2003, Croatia recorded 4,682 (8.9%, 95% Confidence interval 8.4-9.4) in the strike period from the 15th of January to the 14th of February 2003 or 1.1 deaths per 1000. No deviations of the 15th of January to the 14th of February period's share of the death total in relation to other observation periods were noted. It is impossible to associate the strike based on the figures shown in this paper with either an increase or decrease in population mortality. 相似文献
134.
Types and the number of stomata in the following Arum species: Arum italicum Mill., Arum maculatum var. maculatum L. and Arum maculatum var. immaculatum L., Arum alpinum var. pannonicum Terpo. and Arum alpinum var. intermedium Schur. in three different locations in Zablaće, Normanci and Bilje were investigated. The most prevalent stomata type at
both upper and lower epidermis for each Arum species was mostly stomata type paracytic, followed by hexacytic, tetracytic or brachyparacytic as far as locality is concerned.
Helicocytic type was more prevalent in Arum alpinum var. pannonicum Terpo. and Arum alpinum var. intermedium Schur. at Bilje. Other stomata types were very rare. A striking regularity in the occurrence of stomata types was not found
within a single species. Some stomata types, however, were found either at adaxial or abaxial epidermis or were not present
at all. The number of stomata per square mm varied from 25 to 651. A statistically significant difference in the number of
stomata per square mm at upper and lower epidermis among Arum species was determined in locations Zablaće and Normanci, whereas no statistically significant differences were found in
location Bilje. 相似文献
135.
Levels of pro-inflammatory cytokines produced from cord blood in-vitro are pathogen dependent and increased in comparison to adult controls 总被引:2,自引:0,他引:2
BACKGROUND: Overproduction of pro-inflammatory cytokines may play a role in increased morbidity and mortality from neonatal sepsis. Objective of this study was to compare secretion of pro-inflammatory cytokines by the cord blood cells of healthy term neonates to the venous blood cells of healthy adults in vitro after stimulation with common neonatal pathogens. METHOD: Blood samples were cultured in the presence of heat-killed group B beta-hemolytic streptococci (GBS), Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epi). Concentrations of secreted cytokines (interleukine-6, IL-6, tumor necrosis factor-alpha, TNF-alpha, interleukine-1 beta, IL-1beta and interleukine-8, IL-8) were measured after 0, 1, 2 and 4 h of incubation using chemiluminescent immunometric automated assay. RESULTS: Blood samples from 22 neonates and 16 adults were compared. After stimulation by GBS and E. coli, cord blood cells secreted significantly higher levels of IL-6 and IL-8 than blood cells of healthy adults. In cord blood, E. coli induced secretion of higher concentration of IL-6, TNF-alpha, IL-1beta and IL-8 than S. epi, and more IL-6 than GBS; GBS induced more IL-1beta than S.epi. CONCLUSIONS: Response of cord blood to microbial activators is different from that of adult controls. Each isolate of heat-killed bacteria induced different amount of pro-inflammatory cytokines in vitro. This may represent a useful in vitro virulence test. 相似文献
136.
A fragmented human calotte was discovered during the early 1950s near Ba?ki Petrovac (Serbia), in association with Palaeolithic stone tools. After its initial publication, the fossil specimen remained largely unknown outside of the Serbian academe and no detailed comparative study has ever been carried out. Since the whereabouts of the fossil itself are currently unknown, and given its potential significance for the Pleistocene human evolution, we re-examine the data published by 0255 and 0260. Using the original measurements, mostly taken on the frontal bone, and a wide comparative sample of 68 fossil specimens, the fossil was compared and analyzed by statistical multivariate methods. We also conducted a visual examination of the morphology based on the available photographic material. Our analysis reveals phenetic similarity with Middle Pleistocene archaic Homo from Africa and anatomically modern Homo sapiens. However, the absence of primitive cranial traits in Ba?ki Petrovac indicates a clear modern Homo sapiens designation. Although lost at the moment, there is a chance for the re-discovery of the fossil in the years to come. This would give us an opportunity to acquire absolute dates and to study the specimen in a more detailed manner. 相似文献
137.
Gus Lawrence Christopher C. Brown Blake A. Flood Surya Karunakaran Margarita Cabrera Mirjana Nordmann Christian Ungermann Rutilio A. Fratti 《Molecular biology of the cell》2014,25(10):1608-1619
Maturation of organelles in the endolysosomal pathway requires exchange of the early endosomal GTPase Rab5/Vps21 for the late endosomal Rab7/Ypt7. The Rab exchange depends on the guanine nucleotide exchange factor activity of the Mon1-Ccz1 heterodimer for Ypt7. Here we investigate vacuole binding and recycling of Mon1-Ccz1. We find that Mon1-Ccz1 is absent on vacuoles lacking the phosphatidic acid phosphatase Pah1, which also lack Ypt7, the phosphatidylinositol 3-kinase Vps34, and the lipid phosphatidylinositol 3-phosphate (PI3P). Interaction of Mon1-Ccz1 with wild-type vacuoles requires PI3P, as shown in competition experiments. We also find that Mon1 is released from vacuoles during the fusion reaction and its release requires its phosphorylation by the type 1 casein kinase Yck3. In contrast, Mon1 is retained on vacuoles lacking Yck3 or when Mon1 phosphorylation sites are mutated. Phosphorylation and release of Mon1 is restored with addition of recombinant Yck3. Together the results show that Mon1 is recruited to endosomes and vacuoles by PI3P and, likely after activating Ypt7, is phosphorylated and released from vacuoles for recycling. 相似文献
138.
139.
Mitrović BM Vitorović G Vićentijević M Vitorović D Pantelić G Lazarević-Macanović M 《Radiation and environmental biophysics》2012,51(1):79-84
The aim of the present study was to investigate distribution of (137)Cs in leg and breast meat of broilers and pheasants following single alimentary contamination and administration of two protectors (AFCF and clinoptilolite). The birds were administered a single dose of (137)CsCl, with an activity of 750?Bq. Protectors were given via gastric tube or mixed in the forage pellets. AFCF given via gastric tube decreased the (137)Cs concentration by a factor of 7.8 in broilers leg meat and 7.4 in broilers breast meat. When AFCF was mixed in pellets, the (137)Cs concentration was 19.5 times lower in broilers leg meat and 22.1 times lower in broilers breast meat, than in the control group. In pheasants, AFCF administered via gastric tube decreased the (137)Cs concentration by a factor of 12.4 in leg meat and by a factor of 13.7 in breast meat, respectively. In group 4, where pheasants were administered AFCF mixed in pellets, the (137)Cs concentration was 3.7 times lower in leg and breast meat, than in the control group. For comparison, clinoptilolite administered via gastric tube decreased the (137)Cs concentration 1.8 times in broilers leg meat and 2.0 times in breast meat, compared to the control group. In pheasants, (137)Cs concentration was 2.9 times lower in leg meat and 2.6 times lower in breast meat. Clinoptilolite mixed in the feed had relatively low efficiency of protection in broilers ((137)Cs concentration was 1.4 times lower in leg meat and 1.6 lower in breast meat). A similar trend was observed in pheasants ((137)Cs concentration was 1.6 lower in leg and breast meat). 相似文献
140.
The aim of this study was to construct new Croatian growth charts for body height and weight of boys and girls aged 6.5 to 18.5 years and to investigate differences between our and pre-existing studies. Analysis was based on a multistage stratified sample representative for school children aged 6.5 to 18.5, 6046 boys and 5656 girls. Growth reference was constructed using LMS method. Present results demonstrated an increment of body height and weight during the last two decades. Highest increase of body height is in boys aged 13-14 years 6.5 cm, in girls aged 12 years is 5.0 cm. Highest increase of body weight is in 16 year age group of boys 8.7 kg and in 11-12 year age group of girls 5.2 kg. In conclusion, regarding presence of secular trend because previously used growth charts in Croatia are obsolete. 相似文献