全文获取类型
收费全文 | 2506篇 |
免费 | 139篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 58篇 |
妇产科学 | 39篇 |
基础医学 | 267篇 |
口腔科学 | 30篇 |
临床医学 | 164篇 |
内科学 | 752篇 |
皮肤病学 | 80篇 |
神经病学 | 148篇 |
特种医学 | 51篇 |
外科学 | 407篇 |
综合类 | 37篇 |
一般理论 | 2篇 |
预防医学 | 112篇 |
眼科学 | 68篇 |
药学 | 172篇 |
中国医学 | 5篇 |
肿瘤学 | 255篇 |
出版年
2023年 | 21篇 |
2022年 | 12篇 |
2021年 | 91篇 |
2020年 | 55篇 |
2019年 | 81篇 |
2018年 | 58篇 |
2017年 | 57篇 |
2016年 | 64篇 |
2015年 | 71篇 |
2014年 | 124篇 |
2013年 | 167篇 |
2012年 | 242篇 |
2011年 | 257篇 |
2010年 | 120篇 |
2009年 | 112篇 |
2008年 | 183篇 |
2007年 | 136篇 |
2006年 | 182篇 |
2005年 | 131篇 |
2004年 | 106篇 |
2003年 | 86篇 |
2002年 | 69篇 |
2001年 | 30篇 |
2000年 | 15篇 |
1999年 | 15篇 |
1998年 | 12篇 |
1997年 | 10篇 |
1996年 | 5篇 |
1995年 | 13篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 7篇 |
1991年 | 11篇 |
1990年 | 10篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1969年 | 2篇 |
1964年 | 2篇 |
1933年 | 3篇 |
1930年 | 4篇 |
1929年 | 6篇 |
排序方式: 共有2658条查询结果,搜索用时 331 毫秒
1.
Turnbull Chris D. Stockley James A. Madathil Shyam Huq Syed S. A. Cooper Brendan G. Ali Asad Wharton Simon Stradling John R. Heitmar Rebekka 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2022,260(7):2129-2139
Graefe's Archive for Clinical and Experimental Ophthalmology - Retinal microvascular endothelial dysfunction is thought to be of importance in the development of ocular vascular diseases.... 相似文献
2.
3.
4.
Ramanathan Sundar Varma Shashi Kumar Rao Kolli Madhusudana Muralidharan Srinivasan 《Indian Journal of Thoracic and Cardiovascular Surgery》2004,20(4):164-166
Background Extended trans septal (ETS) approach for mitral valve surgery often divides the artery to the Sino-Atrial node. The clinical
implication of this is contentious. We analyzed our early results with ETS approach.
Methods Between June 1998 and September 2003 eleven patients underwent mitral valve surgery by ETS approach. Six were females. Age
ranged from 19 years to 67 years (median 40 years). Six underwent mitral valve replacement (MVR). Four underwent aortic and
mitral (double) valve replacement (DVR). One had mitral valve repair. Three had additional procedures (tricuspid valve repair=1,
Coronary artery bypass=1, Aorto bifemoral graft=1). Cardiopulmonary bypass ranged from 64 minutes to 77 minutes (median 72
minutes) for MVR and 112 minutes to 178 minutes (median 140 minutes) for DVR. Aortic cross clamp times ranged from 39 minutes
to 52 minutes (median 47 minutes) for MVR and 74 minutes to 120 minutes (median 95 minutes) for DVR.
Results There was no mortality or morbidity attributed to the ETS approach. One early death in emergency DVR was due to heart failure.
Three patients needed seqeuntial pacing in the immediate post-operative period. Nine out of ten survivors were back to their
preoperative rhythms on hospital discharge (6 sinus rhythm; 3 atrial fibrillation). One patient with preoperative trifascicular
block who underwent reoperation to fix a paravalvular mitral leak needed a permanent pacemaker (VVI). The follow-up ranged
from 1 month to 64 months (median 6 months) and is 100% complete. There was no late death or new arrhythmia.
Conclusions Extended trans septal approach is safe. It gives excellent exposure of the mitral valve. division of the sinus node artery
is not deleterious in the short to intermediate term.
Presented at the 50th Annual Meeting of IACTS. New Delhi, Feb. 2004. 相似文献
5.
Spontaneous gall bladder perforation in infants is rare. We report a 3-month-old male infant who presented with progressive abdominal distension, low-grade fever, bilateral hydrocele and acholic stools. Ultrasonography showed free fluid in the peritoneal cavity, which was bile-stained on paracentesis. Surgical exploration revealed sterile biliary peritonitis and a gangrenous gall bladder. Partial cholecystectomy with external biliary drainage resulted in satisfactory recovery. 相似文献
6.
7.
PET imaging of oncogene overexpression using 64Cu-vasoactive intestinal peptide (VIP) analog: comparison with 99mTc-VIP analog. 总被引:13,自引:0,他引:13
Mathew L Thakur Mohan R Aruva Jean Gariepy Paul Acton Satish Rattan Shyam Prasad Eric Wickstrom Abass Alavi 《Journal of nuclear medicine》2004,45(8):1381-1389
The purpose of this study was to assess the feasibility of PET imaging of oncogene VPAC1 receptors overexpressed in human breast cancer cells. METHODS: Vasoactive intestinal peptide (VIP) analog (TP3982) was synthesized to harbor a carboxy-terminus lysine (Lys) residue separated from VIP-asparagine (Asn(28)) by 4-aminobutyric acid (Aba) as a spacer. Lys was derivatized with diaminopropionic acid coupled to a pair of dibenzoylthioglycolic acid residues as protecting groups. The analog was labeled with (64)Cu at pH 9 ((64)Cu-TP3982) and (99m)Tc at pH 12 ((99m)Tc-TP3982). (99m)Tc-TP3982 and VIP derivatized with Aba-GAGG and labeled with (99m)Tc ((99m)Tc-TP3654) were used as reference agents. Smooth muscle relaxivity assays performed with each derivative and compared with unaltered VIP(28) demonstrated functional integrity. In vitro stability of (64)Cu-TP3982 was determined by challenging the complex with 100-mol excess of diethylenetriaminepentaacetic acid (DTPA), human serum albumin (HSA), and cysteine. In vivo stability was determined in urine and serum for up to 24 h. The mass of the Cu-TP3982 complex was determined by mass spectrometry. Human T47D breast tumor xenografts were grown in athymic nude mice. Planar scintigraphic imaging was performed at 4 and 24 h after the intravenous administration of (99m)Tc-TP3982 and (99m)Tc-TP3654 and PET imaging was performed using a small animal MOSAIC PET scanner, also at 4 and 24 h after injection of (64)Cu-TP3982. Tissue-distribution studies were also performed. In a separate experiment, receptors were blocked by intravenous injection of authentic VIP(28) 30 min before the administration of (64)Cu-TP3982 and tissue distribution was examined. RESULTS: (64)Cu-TP3982 labeling yields were 98% +/- 1.2% and those for (99m)Tc-TP3982 and (99m)Tc-TP3654 were 98.2% +/- 1.1% and 97% +/- 1.6%, respectively. The biologic activity of both VIP analogs was uncompromised. When (64)Cu-TP3982 was challenged with 100-mol excess of DTPA, HSA, or cysteine, >98% radioactivity remained as (64)Cu-TP3982. In vivo, >98% of (64)Cu circulating in plasma remained as (64)Cu-TP3982. Of the (64)Cu excreted in urine 4, 20, and 24 h after injection, >98%, 89.9% +/- 0.9%, and 85% +/- 3%, respectively, were bound to TP3982. The mass of Cu-TP3982 as determined by surface-enhanced laser desorption/ionization time of flight (SELDI-TOF) was 4,049.7 Da. Four hours after receptor blocking with VIP(28), there was a significant reduction in uptake of all tissues except in the liver. With (64)Cu-TP3982, the 4-h postinjection tumor uptake was 10.8 +/- 2.1 %ID/g versus 0.5 +/- 0.02 %ID/g and 0.24 +/- 0.08 %ID/g for (99m)Tc-TP3982 and (99m)Tc-TP3654, respectively. Twenty-four hours after injection, the corresponding numbers were 17 +/- 0.7 %ID/g, 0.77 +/- 0.1 %ID/g, and 0.23 +/- 0.1 %ID/g. The severalfold greater uptake (21.2-74) of (64)Cu-TP3982 is attributable to the in vivo stability of the agent. CONCLUSION: The results suggest that the uncompromised biologic activity and the significantly greater tumor uptake of (64)Cu-TP3982, combined with the high sensitivity and enhanced resolution of PET imaging, make (64)Cu-TP3982 highly desirable for further studies in PET imaging of oncogene receptors overexpressed in breast and other types of cancers. 相似文献
8.
Vijay K. Singh Sumita Biswas Krishna B. Mathur Wahajul Haq Satyendra K. Garg Shyam S. Agarwal 《Immunologic research》1998,17(3):345-368
Splenopentin (SP-5, Arg-Lys-Glu-Val-Tyr) and thymopentin (TP-5, Arg-Lys-Asp-Val-Tyr) are synthetic immunomodulating peptides corresponding to the region 32–34 of a splenic product called splenin (SP) and the thymic hormone thymopoietin (TP), respectively. TP was originally isolated as a 5-kDa (49-amino acids) protein from bovine thymus while studying effects of the thymic extracts on neuromuscular transmission and was subsequently observed to affect T cell differentiation and function. TP I and II are two closely related polypeptides isolated from bovine thymus. A radioimmunoassay for TP revealed a crossreaction with a product found in spleen and lymph node. This product, named splenin, differs from TP only in position 34, aspartic acid for bovine TP and glutamic acid for bovine splenin and it was called TP III as well. Synthetic pentapeptides (TP-5) and (SP-5), reproduce the biological activities of TP and SP, respectively. It is now evident that various forms of TPs were created by proteolytic cleavage of larger proteins during isolation. cDNA clones have been isolated for three alternatively spliced mRNAs that encodes three distinct human T cell TPs. The immunomodulatory properties of TP, SP, TP-5, SP-5 and some of their synthetic analogs reported in the literature have been briefly reviewed. 相似文献
9.
Our inability to associate distant regulatory elements with the genes they regulate has largely precluded their examination for sequence alterations contributing to human disease. One major obstacle is the large genomic space surrounding targeted genes in which such elements could potentially reside. In order to delineate gene regulatory boundaries, we used whole-genome human-mouse-chicken (HMC) and human-mouse-frog (HMF) multiple alignments to compile conserved blocks of synteny (CBSs), under the hypothesis that these blocks have been kept intact throughout evolution at least in part by the requirement of regulatory elements to stay linked to the genes they regulate. A total of 2116 and 1942 CBSs >200 kb were assembled for HMC and HMF, respectively, encompassing 1.53 and 0.86 Gb of human sequence. To support the existence of complex long-range regulatory domains within these CBSs, we analyzed the prevalence and distribution of chromosomal aberrations leading to position effects (disruption of a gene's regulatory environment), observing a clear bias not only for mapping onto CBS but also for longer CBS size. Our results provide an extensive data set characterizing the regulatory domains of genes and the conserved regulatory elements within them. 相似文献
10.