全文获取类型
收费全文 | 1413篇 |
免费 | 110篇 |
国内免费 | 1篇 |
专业分类
1524篇 |
出版年
2023年 | 22篇 |
2022年 | 25篇 |
2021年 | 37篇 |
2020年 | 52篇 |
2019年 | 75篇 |
2018年 | 67篇 |
2017年 | 50篇 |
2016年 | 64篇 |
2015年 | 61篇 |
2014年 | 68篇 |
2013年 | 106篇 |
2012年 | 95篇 |
2011年 | 81篇 |
2010年 | 61篇 |
2009年 | 37篇 |
2008年 | 73篇 |
2007年 | 51篇 |
2006年 | 69篇 |
2005年 | 43篇 |
2004年 | 35篇 |
2003年 | 37篇 |
2002年 | 36篇 |
2001年 | 32篇 |
2000年 | 27篇 |
1999年 | 27篇 |
1998年 | 17篇 |
1997年 | 10篇 |
1996年 | 25篇 |
1995年 | 15篇 |
1994年 | 5篇 |
1993年 | 13篇 |
1992年 | 14篇 |
1991年 | 5篇 |
1990年 | 10篇 |
1989年 | 17篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 8篇 |
1983年 | 3篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1971年 | 2篇 |
1966年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有1524条查询结果,搜索用时 15 毫秒
1.
2.
3.
A case of chromomycosis in which hyperthermia proved effective is reported. The patient was a 56-year-old male bean curd maker who, without any previous history of minor trauma, developed on the extensor side of the left upper arm an eczematous lesion that underwent gradual radial expansion. The lesion showed a well-defined, 7×10 cm infiltrated erythematous plaque with the central area healed and, at the upper and lower borders, adherent scales and crusts on the surface. Histological examination revealed granulomatous changes in the dermis, as well as sclerotic cells within giant cells and microabscesses. On culturing,Fonsecaea pedrosoi was isolated. The patient was treated with disposable chemical pocket warmers, which were secured over the lesion with a rather tight elastic bandage, so that they kept the affected area warm for 24 hours a day. After a month of such hyperthermic treatment, the erythema and infiltration had decreased considerably, and microscopic examination and culture of the crusts both yielded negative results. Examination of biopsy specimens of the lesion after the third month showed that it had cicatrized. The treatment was stopped after 4 months, and no relapse occurred. We also summarize the published results of local hyperthermic treatment of chromomycosis in Japan. 相似文献
4.
5.
4-Thiaproline reduces heart lipid peroxidation and collagen accumulation in the diabetic db/db mouse
Summary Collagen accumulation is a main pathological feature of diabetic cardiomyopathy. The underlying mechanisms seem to be increased cross linking by reactive carbonyles. The purpose of the study was to decrease the collagen content of total ventricular tissue by the oral administration of thiaproline, which could reduce collagen due to its functions as a proline analogue, blocking collagen production and as a free oxygen radical scavenger, blocking reactive carbonyles and oxygen species and subsequently collagen cross linking.Thiaproline was administered to genetically diabetic db/db mice and compared to untreated animals. Total ventricular collagen as expressed by hydroxyproline was significantly lower in the treated group (means 0.23 micromoles/10 tissue in the treated vs 0.35 micromoles/100 mg tissue in the untreated group, p < 0.001). Significantly more collagen could be eluted in the treated group (p < 0.001) and carboxymethyllysine was significantly reduced in the treated group (p < 0.001). Di-tyrosine and glycemic control did not differ between the groups. Glutathione was significantly increased in the TP treated experimental group (p < 0.001) and lipid peroxidation products were significantly decreased (means 0.221 absorbance in the treated group versus 0.321 absorbance in the untreated diabetic group) correlating with total ventricular collagen content (r = 0.87, p < 0.01).We conclude that thiaproline reduced total ventricular collagen content by inhibiting collagen cross linking as reflected by increased solubility of collagen and expressed by higher elution quantity of collagen. Thiaproline, and/or its metabolites induced increase of heart glutathione which may well have been scavenging reactive carbonyles derived from lipid peroxidation and advanced stage nonenzymatic glycosylation as shown by decreased total ventricular carboxy-methyllysine and lipid peroxidation products paralleling reduced heart collagen content.It remains to be shown that the successful reduction of heart collagen by thiaproline is paralleled by improved functional properties. 相似文献
6.
Soares TN Melo DB Resende LV Vianello RP Chaves LJ Collevatti RG Telles MP 《American journal of botany》2012,99(2):e72-e73
? Premise of the study: Microsatellite markers were developed for the population genetic analyses of the neotropical tree Dipteryx alata (Fabaceae). ? Methods and Results: Microsatellites were developed from a genomic shotgun library. Polymorphism at each microsatellite loci was analyzed based on 94 individuals from three populations. Eight loci amplified successfully and presented one to 10 alleles, and expected heterozygosities ranged from 0.097 to 0.862. Four loci also amplified in Pterodon emarginatus and presented similar polymorphism. ? Conclusion: The eight microsatellite primer pairs are potentially suitable for population genetic studies and successfully amplified in another Fabaceae species. 相似文献
7.
8.
9.
Pereira-Lorenzo S Costa RM Ramos-Cabrer AM Ciordia-Ara M Ribeiro CA Borges O Barreneche T 《Génome》2011,54(4):301-315
This is a large-scale molecular study based on simple sequence repeat (SSR) loci of the diversification process in chestnut cultivars from Portugal and Spain, from the northern Iberian Peninsula to the Canary Islands and the Azores. A total of 593 grafted chestnut trees (Castanea sativa Mill.) were analysed with 10 SSRs: 292 from Portugal and 301 from Spain. Some of the trees studied were more than 300 years old. Accessions were analysed using a model-based Bayesian procedure to assess the geographical structure and to assign individuals to reconstructed populations based on the SSR genotypes. We found 356 different genotypes with a mean value of clonality of 33% owing to grafting. Mutations accounted for 6%, with hybridization being the main diversification process that can explain the great diversity found. Ten main cultivar groups were detected: four in northern Spain, five in the centre of the Iberian Peninsula, and one in southern Spain related to the centre of the Iberian Peninsula. This work demonstrated that cultivar origin and the diversification process was a combination of clonal propagation of selected seedlings, hybridization, and mutations, which allowed high levels of diversity to be maintained with respect to selected clones for fruit production. Furthermore, seedlings and graft sticks facilitated the transport to new destinations in the colonization process, transporting sometimes more than 3000 km if we consider the Azores and the Canary Islands. 相似文献
10.
Alberto V. Borges Gaëlle Speeckaert Willy Champenois Mary I. Scranton Nathalie Gypens 《Ecosystems》2018,21(4):583-599
Dissolved CH4 concentrations in the Belgian coastal zone (North Sea) ranged between 670 nmol l?1 nearshore and 4 nmol l?1 offshore. Spatial variations of CH4 were related to sediment organic matter (OM) content and gassy sediments. In nearshore stations with fine sand or muddy sediments, the CH4 seasonal cycle followed water temperature, suggesting methanogenesis control by temperature in these OM-rich sediments. In offshore stations with permeable sediments, the CH4 seasonal cycle showed a yearly peak following the chlorophyll-a spring peak, suggesting that in these OM-poor sediments, methanogenesis depended on freshly produced OM delivery. This does not exclude the possibility that some CH4 might originate from dimethylsulfide (DMS) or dimethylsulfoniopropionate (DMSP) or methylphosphonate transformations in the most offshore stations. Yet, the average seasonal CH4 cycle was unrelated to those of DMS(P), very abundant during the Phaeocystis bloom. The annual average CH4 emission was 126 mmol m?2 y?1 in the most nearshore stations (~4 km from the coast) and 28 mmol m?2 y?1 in the most offshore stations (~23 km from the coast), 1260–280 times higher than the open ocean average value (0.1 mmol m?2 y?1). The strong control of CH4 by sediment OM content and by temperature suggests that marine coastal CH4 emissions, in particular in shallow areas, should respond to future eutrophication and warming of climate. This is supported by the comparison of CH4 concentrations at five stations obtained in March 1990 and 2016, showing a decreasing trend consistent with alleviation of eutrophication in the area. 相似文献