全文获取类型
收费全文 | 194篇 |
免费 | 6篇 |
专业分类
200篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 1篇 |
2019年 | 13篇 |
2018年 | 13篇 |
2017年 | 3篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 9篇 |
2013年 | 11篇 |
2012年 | 1篇 |
2011年 | 5篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 11篇 |
2007年 | 5篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 8篇 |
2003年 | 4篇 |
2002年 | 10篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
排序方式: 共有200条查询结果,搜索用时 15 毫秒
71.
《Revue de Micropaléontologie》2015,58(1):51-56
We considered the geometrical properties of skeletons of the genus Pantanellium, a type of Mesozoic radiolarian. We constructed four 3D models of fossil specimens of Pantanellium, using X-ray Micro-CT and layered manufacturing technology. Focusing on cortical shells, we approximated the skeletal structures with convex polyhedrons and investigated their geometrical properties. We summarized these properties using planar graphs. The geometrical properties differ for fossils that are believed to belong to the same species. The results of numerical simulations based on a mathematical model for spherical radiolarians were partially consistent with the skeletal structures of the specimens. We conclude that the skeletal structure of the genus Pantanellium is not fixed and is not completely optimized from the viewpoint of symmetry. 相似文献
72.
73.
74.
《Endocrinología y nutrición》2014,61(8):426-433
Background and objectiveIn Spain, data suggest that 13.8% of adults have diabetes. Two important aspects in diabetes management are mild hypoglycemic episodes and poor treatment adherence. This study assesses the impact of missed insulin doses and prevalence of mistimed and reduced insulin doses and mild hypoglycemia in patients with type 2 diabetes treated with basal insulin analogues in Spain, and compares the data collected to pooled data from 8 other European countries (OECs).Materials and methodsGAPP2 was an international, online, cross-sectional study of diabetic patients aged ≥40 years treated with long-acting insulin analogues and their healthcare professionals. Patients and healthcare professionals were recruited from online research panels. Data reported in Spain are compared to pooled data from 8 OECs.ResultsIn Spain, 1–3% of patients reported they had reduced, missed, or mistimed at least one insulin does in the previous month. Significantly more OEC patients reported dosing irregularities (15–23%; all P < 0.01). In Spain, 77% of patients were worried and 59% felt guilty for missing a dose of basal insulin, while 24% reported that they were very worried about nocturnal hypoglycemia. Significantly fewer OEC patients reported worrying (47%; P < 0.01) and feeling guilty (37%; P < 0.01) about missing an insulin dose, or worry about nocturnal hypoglycemia (12%; P < 0.01).ConclusionsIn Spain, patients with type 2 diabetes report fewer dosing irregularities and hypoglycemic episodes as compared to patients from OECs. However, Spanish patients appear to have a reduced quality of life related to hypoglycemia as well as worry and guilt related to insulin dosing irregularities. 相似文献
75.
Inhibition of testosterone-induced sexual behavior in the castrated male rat by aromatase blockers 总被引:1,自引:1,他引:1
The effect of some aromatase inhibitors (aminoglutethimide, 1,4,6-androstatrien-3, 17-dione, and 4-hydroxy-androstenedione) on testosterone propionate (TP)-induced copulatory behavior was tested in sexually inexperienced castrated male rats. A single injection of 6 mg of TP induced mounting in 48% and ejaculatory pattern in 19% of the rats within 120 hr. Treatment with the aromatase inhibitors (injections every 12 hr for 108 hr) suppressed ejaculation in all but one rat and significantly reduced the number of rats mounting and intromitting. Concurrent administration of estradiol benzoate (EB, 1 or 3 μg every 12 hr) prevented the inhibitory effect of aromatase blockers. No inhibitory effect of the aromatization blockers was observed in rats in which sexual behavior was induced by dihydrotestosterone (1 mg/day) and EB (2.5 μg/day) for 20 days. The results support the concept that aromatization is an essential step for the induction of male sexual behavior by androgen in the rat. 相似文献
76.
用缺口双链DNA的定向突变方法分别将胰岛素前体中B链第 2 2、2 8、2 9和 3 0位改变为Asp、Lys、Pro和Lys,酵母分泌表达的前体经胰蛋白酶直接酶切 ,得到重组 [B2 2Asp、B2 8Lys、B2 9Pro、B3 0Lys]人胰岛素。它与受体的结合能力约为猪胰岛素的 6% ,而体内生物活力保留 5 0 %。通过FPLC分子筛测定其自身结合能力 ,在生理条件下浓度达 10 -4mol/L时它以单体形式存在。作为可抗胰蛋白酶酶解的单体胰岛素类似物 ,它可能具有一定的应用前景 相似文献
77.
Teiten MH Even P Burgos P Frochot C Aubert S Carré MC Bolotine L Merlin JL Guillemin F Viriot ML 《Comptes rendus biologies》2002,325(4):487-493
Our main objective is to enlarge the fluorescence use in biosciences, with especially the photodynamic therapy (PDT) used for cancer treatment as one of the target applications. Meta-tetra(hydroxyphenyl)chlorin (m-THPC) is a second-generation photosensitiser, applied in photodynamic therapy. The localisation of this sensitiser as well as its induced cell death mechanisms in human breast cancer cells (MCF-7 and its resistant subline MCF-7DXR, DXR: doxorubicin) were evaluated using fluorescence microscopy. In addition, we will present two additional routes, whose aims are to create new features to respond to the PDT questioning: firstly, the synthesis of fluorescent tracers, with a particular attention to the presence of hydrophilic groups (glucosamine ring) on the basic fluorophore structure to orientate the localisation of the probe and, secondly, the use of scanning near-field optical microscopy to reach a better resolution for the fluorescence microscopy analysis. 相似文献
78.
《L'Anthropologie》2023,127(1):103113
The Acheulean of the southern Iberian Peninsula is markedly similar to the north African Acheulean. However, the characteristics of the stone tool assemblages are heterogeneous and represent complex cultural phenomena. From MIS 15, the lithic assemblages in fluvial (Guadiana, Guadalquivir and Guadalete rivers), fluvio-lacustrine (Solana del Zamborino) and karstic (Cueva del Ángel, Bolomor, Cueva Negra del río Quípar, Cueva Horá and Santa Ana) contexts exhibit analogies and technical differences representative of a phenomenon of multiplicity. Contributing to this phenomenon is the perception of technological stasis or conservatism of the Acheulean technocomplex and the different technical responses articulated by hominins to achieve equivalent results. These equivalences generate the uniformity that allows us to recognise typologies of large cutting tools (LCTs) regardless of the lithic materials used or the organisational structures of the operational sequences. These diversified typologies include handaxes, picks, and cleavers, which maintain a consistent presence despite innovations such as the Levallois flaking method. In some cases, the presence of cleavers and spheroids affects the range of represented typologies. Beneath the uniformity of the handaxes, lie organisational differences in the operational sequences. The changes and differences in the use of flakes to shape handaxes, the representation of cleavers and diversification of shaped-tool typologies all suggest differential cultural behaviours linked in part to divergent contexts. These aspects indicate that this multiplicity is related to diffusion, adaptation and cultural changes produced at the margins of the conservatism of this technocomplex. Observed changes could indicate inter-group cultural replacements, most of which retained a similar techno-typological diversity to that seen in the north African Acheulean until MIS 5. Cyclical climate change during the Middle Pleistocene affected the Strait of Gibraltar, regulating its function and conditioning the circulation of hominins and affecting cultural interactions between southern Iberian groups. 相似文献
79.
Introduction
Open access breast clinics are now widely available and immediate reporting of FNAs of the breast has become an established part of the triple approach to the management of breast disease 1 .
We report the unexpected findings of a case of Hodgkin's disease at such a clinic. The patient was a young woman who initially was thought by both her general practitioner and surgeon to have a fibroadenoma in the axillary tail region of her right breast. The FNA of this lump showed the features of Hodgkin's disease but with widespread necrosis, which was unusual and potentially misleading and which we wish to highlight. A lymph node biopsy confirmed the diagnosis and showed that the patient was suffering from the syncytial variant of nodular sclerosing Hodgkin's disease (NSHD).
This variant probably accounts for about 5% of cases of Hodgkin's disease 2 . Necrosis is a common feature of NSHD; it can range from minute scattered foci to more extensive necrosis of nodules or even involve the entire lymph node. 相似文献
Open access breast clinics are now widely available and immediate reporting of FNAs of the breast has become an established part of the triple approach to the management of breast disease
We report the unexpected findings of a case of Hodgkin's disease at such a clinic. The patient was a young woman who initially was thought by both her general practitioner and surgeon to have a fibroadenoma in the axillary tail region of her right breast. The FNA of this lump showed the features of Hodgkin's disease but with widespread necrosis, which was unusual and potentially misleading and which we wish to highlight. A lymph node biopsy confirmed the diagnosis and showed that the patient was suffering from the syncytial variant of nodular sclerosing Hodgkin's disease (NSHD).
This variant probably accounts for about 5% of cases of Hodgkin's disease
80.
In vitro study of the biological activity of RNAs after incubation of hog liver, heart and brain tissue at room temperature 总被引:2,自引:0,他引:2
The biological activity of RNA, isolated from tissue which was incubated for 1, 3, or 6 hours at room temperature (simulation of post-mortem conditions), was preserved. However, the different organs used differ from each other. When liver is used, qualitative differences in the in vitro translation products are observed, after one hour incubation at room temperature, whereas when heart and brain are used these differences are not observed. We have also shown that relatively small amounts of post-mortem tissue is sufficient for RNA extraction. When using frozen tissue it is absolutely necessary to add RNase inhibitors during thawing to reduce the loss of biological activity. 相似文献