全文获取类型
收费全文 | 12189篇 |
免费 | 836篇 |
国内免费 | 1篇 |
出版年
2023年 | 66篇 |
2022年 | 127篇 |
2021年 | 240篇 |
2020年 | 190篇 |
2019年 | 226篇 |
2018年 | 364篇 |
2017年 | 309篇 |
2016年 | 471篇 |
2015年 | 724篇 |
2014年 | 708篇 |
2013年 | 954篇 |
2012年 | 1124篇 |
2011年 | 1018篇 |
2010年 | 584篇 |
2009年 | 490篇 |
2008年 | 663篇 |
2007年 | 620篇 |
2006年 | 584篇 |
2005年 | 485篇 |
2004年 | 508篇 |
2003年 | 413篇 |
2002年 | 444篇 |
2001年 | 191篇 |
2000年 | 176篇 |
1999年 | 142篇 |
1998年 | 95篇 |
1997年 | 53篇 |
1996年 | 74篇 |
1995年 | 51篇 |
1994年 | 54篇 |
1993年 | 44篇 |
1992年 | 108篇 |
1991年 | 72篇 |
1990年 | 65篇 |
1989年 | 56篇 |
1988年 | 48篇 |
1987年 | 50篇 |
1986年 | 39篇 |
1985年 | 44篇 |
1984年 | 41篇 |
1983年 | 25篇 |
1982年 | 23篇 |
1981年 | 16篇 |
1980年 | 23篇 |
1979年 | 17篇 |
1978年 | 17篇 |
1977年 | 17篇 |
1974年 | 19篇 |
1973年 | 25篇 |
1972年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
24.
25.
Salomé C. Vilchez Larrea Mariana Schlesinger María L. Kevorkian Mirtha M. Flawiá Guillermo D. Alonso Silvia H. Fernández Villamil 《PloS one》2013,8(6)
Trypanosoma cruzi, etiological agent of Chagas’ disease, has a complex life cycle which involves the invasion of mammalian host cells, differentiation and intracellular replication. Here we report the first insights into the biological role of a poly(ADP-ribose) glycohydrolase in a trypanosomatid (TcPARG). In silico analysis of the TcPARG gene pointed out the conservation of key residues involved in the catalytic process and, by Western blot, we demonstrated that it is expressed in a life stage-dependant manner. Indirect immunofluorescence assays and electron microscopy using an anti-TcPARG antibody showed that this enzyme is localized in the nucleus independently of the presence of DNA damage or cell cycle stage. The addition of poly(ADP-ribose) glycohydrolase inhibitors ADP-HPD (adenosine diphosphate (hydroxymethyl) pyrrolidinediol) or DEA (6,9-diamino-2-ethoxyacridine lactate monohydrate) to the culture media, both at a 1 µM concentration, reduced in vitro epimastigote growth by 35% and 37% respectively, when compared to control cultures. We also showed that ADP-HPD 1 µM can lead to an alteration in the progression of the cell cycle in hydroxyurea synchronized cultures of T. cruzi epimastigotes. Outstandingly, here we demonstrate that the lack of poly(ADP-ribose) glycohydrolase activity in Vero and A549 host cells, achieved by chemical inhibition or iRNA, produces the reduction of the percentage of infected cells as well as the number of amastigotes per cell and trypomastigotes released, leading to a nearly complete abrogation of the infection process. We conclude that both, T. cruzi and the host, poly(ADP-ribose) glycohydrolase activities are important players in the life cycle of Trypanosoma cruzi, emerging as a promising therapeutic target for the treatment of Chagas’ disease. 相似文献
26.
The topography of the auriculotemporal nerve (ATN) root system is the main criterion of this nerve classification. Previous publications indicate that ATN may have between one and five roots. Most common is a one- or two-root variant of the nerve structure. The problem of many publications is the inconsistency of nomenclature which concerns the terms “roots”, “connecting branches”, or “branches” that are used to identify the same structures. This study was performed on 80 specimens (40 adults and 40 fetuses) to propose a classification based on: (i) the number of roots, (ii) way of root division, and (iii) configuration of interradicular fibers that form the ATN trunk. This new classification is a remedy for inconsistency of nomenclature of ATN in the infratemporal fossa. This classification system has proven beneficial when organizing all ATN variants described in previous studies and could become a helpful tool for surgeons and dentists. Examination of ATN from the infratemporal fossa of fetuses (the youngest was at 18 weeks gestational age) showed that, at that stage, the nerve is fully developed. 相似文献
27.
J Ignacio Andrés Jesús Alcázar José M Alonso Adolfo Díaz Javier Fernández Pilar Gil Laura Iturrino Encarna Matesanz Theo F Meert Anton Megens Victor K Sipido 《Bioorganic & medicinal chemistry letters》2002,12(2):249-253
Following the programme started at Janssen Research Foundation searching for 5-HT(2A/2C) antagonists, we now report on the synthesis of a series of substituted 2-(Dimethylaminomethyl)-2,3,3a,8-tetrahydrodibenzo[c,f]isoxazolo[2,3-a]azepine derivatives. The 5-HT(2A), 5-HT(2C) and H(1) receptor affinities as well as the mCPP antagonistic activity of the compounds synthesised is described. 相似文献
28.
Mindaugas Tamoinas Emilija V. Plorina Marta Lange Aleksandrs Derjabo Ilona Kuzmina Dmitrijs Bizuks Janis Spigulis 《Journal of biophotonics》2020,13(3)
This clinical study is a first attempt to use autofluorescence for recurrence diagnosis of skin cancer in postoperative scars. The proposed diagnostic parameter is based on a reduction in scar autofluorescence, evaluated in the green spectral channel. The validity of the method has been tested on 110 postoperative scars from 56 patients suspected of non‐melanoma skin cancer, with eight patients (13 scars) available for the repeated examination. The recurrence diagnosis within a scar has been made after two subsequent autofluorescence check‐ups, representing the temporal difference between the scar autofluorescence amplitudes as a vector. The recognition of recurrence has been discussed to represent the significant deviations from the value of vector angle θ. This new autofluorescence‐based method can be easily integrated into the postoperative monitoring of surgical scars and can help diagnose the recurrence of skin cancer from the early stage of scar development. 相似文献
29.
30.
J Yajeya A Colino J Criado-Gutiérrez A Fernández de Molina 《Revista Espanola de Fisiología》1987,43(2):185-189
The commissural component of the stria terminalis (S. T.) was studied in Equi-Thesin (92.7 mg/kg) anesthetized rats after their exposure in the caudothalamic surface of both hemispheres. Two types of connection between right and left S. T. across the anterior commissure are described: A "direct" connection set up by fibres that run through the S. T. and join the contralateral S. T., and another "indirect" component, formed by cell axons that receive excitatory synaptic contacts from fibres running in the S. T. 相似文献