全文获取类型
收费全文 | 986篇 |
免费 | 161篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 49篇 |
妇产科学 | 9篇 |
基础医学 | 41篇 |
口腔科学 | 13篇 |
临床医学 | 160篇 |
内科学 | 243篇 |
皮肤病学 | 30篇 |
神经病学 | 43篇 |
特种医学 | 118篇 |
外科学 | 182篇 |
综合类 | 48篇 |
现状与发展 | 20篇 |
预防医学 | 57篇 |
眼科学 | 27篇 |
药学 | 62篇 |
中国医学 | 2篇 |
肿瘤学 | 47篇 |
出版年
2024年 | 7篇 |
2023年 | 42篇 |
2021年 | 17篇 |
2020年 | 22篇 |
2019年 | 9篇 |
2018年 | 49篇 |
2017年 | 44篇 |
2016年 | 33篇 |
2015年 | 40篇 |
2014年 | 39篇 |
2013年 | 56篇 |
2012年 | 17篇 |
2011年 | 26篇 |
2010年 | 46篇 |
2009年 | 64篇 |
2008年 | 32篇 |
2007年 | 24篇 |
2006年 | 33篇 |
2005年 | 19篇 |
2004年 | 13篇 |
2003年 | 26篇 |
2002年 | 23篇 |
2001年 | 32篇 |
2000年 | 19篇 |
1999年 | 25篇 |
1998年 | 29篇 |
1997年 | 33篇 |
1996年 | 44篇 |
1995年 | 29篇 |
1994年 | 17篇 |
1993年 | 21篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 15篇 |
1989年 | 14篇 |
1988年 | 17篇 |
1987年 | 15篇 |
1986年 | 12篇 |
1985年 | 12篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1978年 | 12篇 |
1977年 | 8篇 |
1976年 | 8篇 |
1971年 | 5篇 |
1968年 | 5篇 |
1967年 | 5篇 |
1966年 | 5篇 |
1964年 | 5篇 |
1963年 | 5篇 |
排序方式: 共有1165条查询结果,搜索用时 0 毫秒
1.
Paul Wexberg MD BM Richard Pacher MD Suzanne Rdler MD Katharina Kiss MD Gilbert Beran MD Michael Grimm MD Gerald Maurer MD Dietmar Glogar MD FESC 《The Journal of heart and lung transplantation》2002,21(12):583-1263
BACKGROUND: Endothelin, a peptide with strong vasoconstrictive and mitogenic properties, has been found to increase after cardiac transplantation. We therefore assessed the association between its precursor peptide, big endothelin-1, and intimal hyperplasia and coronary flow reserve after heart transplantation. METHODS: Thirty-five patients without hemodynamically significant coronary artery disease after heart transplantation were investigated: Average peak flow velocity in the left anterior descending artery (LAD) was assessed by intracoronary Doppler at baseline as well as after injection of adenosine; coronary flow reserve was calculated as a ratio of both and was corrected for patient age and baseline average peak flow velocity. Lumen, intima + media and total vessel area were measured by intracoronary ultrasound. The plasma concentration of big endothelin-1 in venous blood was determined by radioimmunoassay. RESULTS: Patients with elevated big endothelin-1 levels (>2 fmol/ml) tended to have a decreased corrected coronary flow reserve (2.60 +/- 0.9 vs 3.21 +/- 1.0, p = 0.078). They also had a significantly larger intima + media area (5.82 +/- 2.9 vs 2.37 +/- 2.9 mm(2), p = 0.004) and total vessel area (18.36 +/- 5.8 vs 12.81 +/- 4.8 mm(2), p = 0.012) than those with normal plasma concentrations. CONCLUSIONS: Our study suggests an association between elevated big endothelin-1 plasma levels and the development of intimal hyperplasia and reduction of coronary flow reserve after cardiac transplantation. 相似文献
2.
3.
4.
The computerized database system described was initially developed in 1986 to facilitate analysis of retrospective head and neck cancer data from the Royal Adelaide Hospital Department of Otolaryngology. This has now been expanded to become an on-going patient information management system. It is based on the dBase-III-Plus database package and is implemented on an IBM XT compatible computer. The system was designed to be used by staff without specialist computer skills and is therefore largely “menu-driven.” The main functions include patient record creation, update, and retrieval, and the production of reports including graphical presentations. There is also a powerful but easy to use query facility. The system has already provided much useful epidemiological material but is now beginning to fulfill an even more important role in patient follow-up and in assisting evaluation of alternative treatment protocols. 相似文献
5.
Efficient correction for CT image artifacts caused by objects extending outside the scan field of view 总被引:3,自引:0,他引:3
The purpose of this paper is to develop a method of eliminating CT image artifacts generated by objects extending outside the scan field of view, such as obese or inadequately positioned patients. CT projection data are measured only within the scan field of view and thus are abruptly discontinuous at the projection boundaries if the scanned object extends outside the scan field of view. This data discontinuity causes an artifact that consists of a bright peripheral band that obscures objects near the boundary of the scan field of view. An adaptive mathematical extrapolation scheme with low computational expense was applied to reduce the data discontinuity prior to convolution in a filtered backprojection reconstruction. Despite extended projection length, the convolution length was not increased and thus the reconstruction time was not affected. Raw projection data from ten patients whose bodies extended beyond the scan field of view were reconstructed using a conventional method and our extended reconstruction method. Limitations of the algorithm are investigated and extensions for further improvement are discussed. The images reconstructed by conventional filtered backprojection demonstrated peripheral bright-band artifacts near the boundary of the scan field of view. Images reconstructed with our technique were free of such artifacts and clearly showed the anatomy at the periphery of the scan field of view with correct attenuation values. We conclude that bright-band artifacts generated by obese patients whose bodies extend beyond the scan field of view were eliminated with our reconstruction method, which reduces boundary data discontinuity. The algorithm can be generalized to objects with inhomogeneous peripheral density and to true "Region of Interest Reconstruction" from truncated projections. 相似文献
6.
Mahadevaiah SK; Odorisio T; Elliott DJ; Rattigan A; Szot M; Laval SH; Washburn LL; McCarrey JR; Cattanach BM; Lovell-Badge R; Burgoyne PS 《Human molecular genetics》1998,7(4):715-727
An RNA-binding motif (RBM) gene family has been identified on the human Y
chromosome that maps to the same deletion interval as the 'azoospermia
factor' (AZF). We have identified the homologous gene family (Rbm) on the
mouse Y with a view to investigating the proposal that this gene family
plays a role in spermatogenesis. At least 25 and probably >50 copies of
Rbm are present on the mouse Y chromosome short arm located between Sry and
the centromere. As in the human, a role in spermatogenesis is indicated by
a germ cell-specific pattern of expression in the testis, but there are
distinct differences in the pattern of expression between the two species.
Mice carrying the deletion Yd1, that maps to the proximal Y short arm, are
female due to a position effect resulting in non-expression of Sry ;
sex-reversing such mice with an Sry transgene produces males with a high
incidence of abnormal sperm, making this the third deletion interval on the
mouse Y that affects some aspect of spermatogenesis. Most of the copies of
Rbm map to this deletion interval, and the Yd1males have markedly reduced
Rbm expression, suggesting that RBM deficiency may be responsible for, or
contribute to, the abnormal sperm development. In man, deletion of the
functional copies of RBM is associated with meiotic arrest rather than
sperm anomalies; however, the different effects of deletion are consistent
with the differences in expression between the two species.
相似文献
7.
8.
9.
10.
The toxicokinetics of aluminum (Al) in male Wistar rats was studied after single intragastric (IG) doses of 1000 and 12000 g Al/kg and intravenous (IV) doses of 10, 100, 1000, and 12000 g Al/kg. Serial blood samples, daily samples of urine and feces as well as brain, liver, kidney, spleen, quadriceps muscle, and femur samples were collected. Al was measured by atomic absorption spectrometry. Al blood profiles after IV doses were adequately described by a two-compartment open model. Al toxicokinetics was dose dependent and appeared to plateau at 12000 g/kg. At IV doses between 10 and 1000 g/kg the terminal half-life of elimination from whole blood (t1/2) increased from 29.9±7.8 to 209.3±32.6 min, and the total body clearance (CL) decreased from 2.45±0.64 to 0.28±0.03 ml min–1 kg–1. Following an IV bolus of 10 and 100 g/kg the administered Al was recovered completely from urine (94.4%±9.9% and 98.5%±3.2%). Twenty-nine days after the IV dose of 1000 g/kg daily renal excretion decreased to baseline values while only 55.1%±8.0% of the dose was excreted. Nineteen days after the single IV dose of 1000 g/kg Al accumulated in liver (28.1±7.7 versus 1.7±0.5 g/g of control rats) and spleen (72.5±21.1 versus <0.4 g/g). After the single 1000 g/kg IG dose no absorption of Al was detectable. The IG dose of 12000 g/kg resulted in a maximum blood Al level of 47.9±12.4 g/l after 50 min. The blood concentration time curve fitted a one-compartment open model with a half-life of absorption of 28.2±3.6 min and a t1/2 of 81.2±20.2 min. Cumulative renal Al excretion was 0.18%±0.10% of the dose and oral bioavailability was 0.02%. Seventeen days after the 12000 g/kg IG dose the Al content in femur samples was increased (2.7±1.3 versus 0.6±0.4 g/g). In no case was fecal elimination of incorporated Al observed. 相似文献