全文获取类型
收费全文 | 17650篇 |
免费 | 1382篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 167篇 |
儿科学 | 593篇 |
妇产科学 | 488篇 |
基础医学 | 2425篇 |
口腔科学 | 190篇 |
临床医学 | 2010篇 |
内科学 | 3494篇 |
皮肤病学 | 261篇 |
神经病学 | 2024篇 |
特种医学 | 341篇 |
外科学 | 1845篇 |
综合类 | 101篇 |
一般理论 | 18篇 |
预防医学 | 2491篇 |
眼科学 | 245篇 |
药学 | 1069篇 |
中国医学 | 9篇 |
肿瘤学 | 1303篇 |
出版年
2024年 | 40篇 |
2023年 | 337篇 |
2022年 | 577篇 |
2021年 | 1181篇 |
2020年 | 702篇 |
2019年 | 973篇 |
2018年 | 1035篇 |
2017年 | 691篇 |
2016年 | 708篇 |
2015年 | 765篇 |
2014年 | 974篇 |
2013年 | 1202篇 |
2012年 | 1744篇 |
2011年 | 1710篇 |
2010年 | 789篇 |
2009年 | 656篇 |
2008年 | 1067篇 |
2007年 | 917篇 |
2006年 | 793篇 |
2005年 | 616篇 |
2004年 | 490篇 |
2003年 | 409篇 |
2002年 | 334篇 |
2001年 | 36篇 |
2000年 | 33篇 |
1999年 | 37篇 |
1998年 | 46篇 |
1997年 | 29篇 |
1996年 | 10篇 |
1995年 | 15篇 |
1994年 | 11篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1971年 | 4篇 |
1970年 | 5篇 |
1968年 | 9篇 |
1964年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
A novel regulation mechanism of DNA repair by damage-induced and RAD23-dependent stabilization of xeroderma pigmentosum group C protein 总被引:16,自引:0,他引:16 下载免费PDF全文
Ng JM Vermeulen W van der Horst GT Bergink S Sugasawa K Vrieling H Hoeijmakers JH 《Genes & development》2003,17(13):1630-1645
Primary DNA damage sensing in mammalian global genome nucleotide excision repair (GG-NER) is performed by the xeroderma pigmentosum group C (XPC)/HR23B protein complex. HR23B and HR23A are human homologs of the yeast ubiquitin-domain repair factor RAD23, the function of which is unknown. Knockout mice revealed that mHR23A and mHR23B have a fully redundant role in NER, and a partially redundant function in embryonic development. Inactivation of both genes causes embryonic lethality, but appeared still compatible with cellular viability. Analysis of mHR23A/B double-mutant cells showed that HR23 proteins function in NER by governing XPC stability via partial protection against proteasomal degradation. Interestingly, NER-type DNA damage further stabilizes XPC and thereby enhances repair. These findings resolve the primary function of RAD23 in repair and reveal a novel DNA-damage-dependent regulation mechanism of DNA repair in eukaryotes, which may be part of a more global damage-response circuitry. 相似文献
64.
Peer Arts Jessica Garland Alicia B. Byrne Tristan S.E. Hardy Milena Babic Jinghua Feng Paul Wang Thuong Ha Sarah L. King‐Smith Andreas W. Schreiber April Crawford Nick Manton Lynette Moore Christopher P. Barnett Hamish S. Scott 《American journal of medical genetics. Part A》2020,182(5):1273-1277
Autosomal dominant (de novo) mutations in PBX1 are known to cause congenital abnormalities of the kidney and urinary tract (CAKUT), with or without extra‐renal abnormalities. Using trio exome sequencing, we identified a PBX1 p.(Arg107Trp) mutation in a deceased one‐day‐old neonate presenting with CAKUT, asplenia, and severe bilateral diaphragmatic thinning and eventration. Further investigation by droplet digital PCR revealed that the mutation had occurred post‐zygotically in the father, with different variant allele frequencies of the mosaic PBX1 mutation in blood (10%) and sperm (20%). Interestingly, the father had subclinical hydronephrosis in childhood. With an expected recurrence risk of one in five, chorionic villus sampling and prenatal diagnosis for the PBX1 mutation identified recurrence in a subsequent pregnancy. The family opted to continue the pregnancy and the second affected sibling was stillborn at 35 weeks, presenting with similar severe bilateral diaphragmatic eventration, microsplenia, and complete sex reversal (46, XY female). This study highlights the importance of follow‐up studies for presumed de novo and low‐level mosaic variants and broadens the phenotypic spectrum of developmental abnormalities caused by PBX1 mutations. 相似文献
65.
Björn Gerdle Jessica Elert Karin Henriksson-Larsén 《European journal of applied physiology》1989,58(6):666-673
Summary Peak torque, work, mean power and electromyographic (EMG) activity were recorded for each of 150 repeated isokinetic maximal shoulder flexions (45°–90°) in 23 healthy females. From the EMG signals of trapezius, deltoid, infraspinatus and biceps brachii the mean power frequency and the signal amplitude were determined in real time. The mechanical output showed a steep decrease during the first 40 contractions, followed by a plateau maintained until the end. In all muscles, except the biceps brachii, significant decreases in mean power frequency occurred during the first 40 contractions, showing a tendency to stabilize around the same absolute frequency value. Signal amplitude increased in the trapezius, the deltoid and the infraspinatus, but was constant in the biceps brachii. For some individuals rather high EMG activity was recorded in the muscles during the time the arm was supposed to be passively extended to the starting position, and this was found to be associated with lower strength and endurance levels. Longitudinal analyses showed that the mean power frequencies correlated better than the signal amplitudes with the three mechanical variables. The results suggest that the initial steep decrease in mechanical performance and mean power frequency is caused by fatiguing of type 2 motor units. 相似文献
66.
67.
Cunliffe SL Wyer JR Sutton JK Lucas M Harcourt G Klenerman P McMichael AJ Kelleher AD 《European journal of immunology》2002,32(12):3366-3375
Reliable, efficient systems for producing soluble HLA-DR molecules, suitable for multimerization and use as staining reagents, have proved elusive. We found that the addition of a flexible linker between peptide and N terminus of the DRB1*0101-chain (Crawford, F., Kozono, H., White, J., Marrack, P. and Kappler, J., Immunity 1998. 8: 675-682.), results in greater in vitro folding efficiency of Escherichia coli-expressed alpha- and beta-chains, and increases both the yield and stability of the DRA1*0101/DRB1*0101/peptide complexes. Although a 10-amino acid linker functioned efficiently for a 20mer epitope from HIV p24, a longer linker was required to produce a DR1 MHC class II tetramer with the influenza hemagglutinin epitope (HA(306-318)). The DR1-HA tetramer was able to stain positively over 98% of a specific clone (HA 1.7) with only a brief 30-min incubation. The tetrameric complexes detected clone cells diluted into PBMC, with high sensitivity, coupled with low background staining in CD4(+) cells. It was possible to detect antigen-specific CD4(+) T cells within a population of PBMC stimulated with the HA peptide. This demonstrates the potential to monitor CD4(+) T cell responses in peripheral blood in a number of clinical scenarios. 相似文献
68.
Structure and evolution of the Smith-Magenis syndrome repeat gene clusters, SMS-REPs 总被引:8,自引:2,他引:8 下载免费PDF全文
Park SS Stankiewicz P Bi W Shaw C Lehoczky J Dewar K Birren B Lupski JR 《Genome research》2002,12(5):729-738
An approximately 4-Mb genomic segment on chromosome 17p11.2, commonly deleted in patients with the Smith-Magenis syndrome (SMS) and duplicated in patients with dup(17)(p11.2p11.2) syndrome, is flanked by large, complex low-copy repeats (LCRs), termed proximal and distal SMS-REP. A third copy, the middle SMS-REP, is located between them. SMS-REPs are believed to mediate nonallelic homologous recombination, resulting in both SMS deletions and reciprocal duplications. To delineate the genomic structure and evolutionary origin of SMS-REPs, we constructed a bacterial artificial chromosome/P1 artificial chromosome contig spanning the entire SMS region, including the SMS-REPs, determined its genomic sequence, and used fluorescence in situ hybridization to study the evolution of SMS-REP in several primate species. Our analysis shows that both the proximal SMS-REP (approximately 256 kb) and the distal copy (approximately 176 kb) are located in the same orientation and derived from a progenitor copy, whereas the middle SMS-REP (approximately 241 kb) is inverted and appears to have been derived from the proximal copy. The SMS-REP LCRs are highly homologous (>98%) and contain at least 14 genes/pseudogenes each. SMS-REPs are not present in mice and were duplicated after the divergence of New World monkeys from pre-monkeys approximately 40-65 million years ago. Our findings potentially explain why the vast majority of SMS deletions and dup(17)(p11.2p11.2) occur at proximal and distal SMS-REPs and further support previous observations that higher-order genomic architecture involving LCRs arose recently during primate speciation and may predispose the human genome to both meiotic and mitotic rearrangements. 相似文献
69.
Polarized light imaging has been used to detect the borders of skin cancer and facilitate assessment of cancer boundaries. A design for an inexpensive handheld polarized camera is presented and clinical images acquired with this prototype are shown. The camera is built with two universal serial bus (USB) color video cameras, a polarizing beamsplitter cube, and a 4x objective lens. Illumination is provided by three white LEDs and a sheet polarizer. Horizontal and vertical linearly polarized reflected images are processed at 7 frames/s and a resulting polarized image is displayed on screen. We compare the performances of cheap USB camera and a 16-bit electronically cooled camera. Dark noise and image repeatability are compared. In both cases, the 16-bit camera outperforms the USB cameras. Despite these limitations, the results obtained with this USB prototype are very satisfactory. Examples of polarized images of lesions taken prior to surgery are presented. 相似文献