全文获取类型
收费全文 | 1681篇 |
免费 | 53篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 181篇 |
妇产科学 | 23篇 |
基础医学 | 145篇 |
口腔科学 | 34篇 |
临床医学 | 160篇 |
内科学 | 238篇 |
皮肤病学 | 11篇 |
神经病学 | 139篇 |
特种医学 | 110篇 |
外科学 | 258篇 |
综合类 | 37篇 |
一般理论 | 2篇 |
预防医学 | 68篇 |
眼科学 | 49篇 |
药学 | 129篇 |
中国医学 | 7篇 |
肿瘤学 | 122篇 |
出版年
2023年 | 13篇 |
2022年 | 23篇 |
2021年 | 61篇 |
2020年 | 28篇 |
2019年 | 46篇 |
2018年 | 61篇 |
2017年 | 47篇 |
2016年 | 45篇 |
2015年 | 40篇 |
2014年 | 68篇 |
2013年 | 97篇 |
2012年 | 162篇 |
2011年 | 150篇 |
2010年 | 85篇 |
2009年 | 64篇 |
2008年 | 105篇 |
2007年 | 86篇 |
2006年 | 66篇 |
2005年 | 73篇 |
2004年 | 62篇 |
2003年 | 56篇 |
2002年 | 54篇 |
2001年 | 29篇 |
2000年 | 26篇 |
1999年 | 22篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 17篇 |
1991年 | 19篇 |
1990年 | 17篇 |
1989年 | 17篇 |
1988年 | 8篇 |
1987年 | 11篇 |
1986年 | 8篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 8篇 |
1981年 | 4篇 |
1973年 | 4篇 |
1968年 | 4篇 |
1967年 | 2篇 |
1966年 | 2篇 |
1965年 | 1篇 |
1961年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有1734条查询结果,搜索用时 15 毫秒
1.
Exposure to air pollution affects pulmonary functions adversely. Effect of exposure to pollution on diurnal variation of peak flow was assessed in healthy students. Three hundred healthy age-matched nonsmoker students were studied. They were categorized into two groups on the basis of their residence: commuters and living on campus. Peak expiratory flow (PEF) recordings were made twice daily for 2 days with the Pink City Flow Meter. The measurement was then used to calculate for each subject the amplitude percentage mean, which is an index for expressing PEF variability for epidemiological purposes (Higgins BG, Britton JR, Chinns Jones TD, Jenkinson D, Burnery PG, Tattersfield AE. Distribution of peak expiratory flow variability in a population sample. Am Rev Respir Dis 1989; 140:1368-1372). Air pollution parameters were quantified by measurement of sulfur dioxide (SO2), oxides of nitrogen (NO2), carbon monoxide (CO), and respirable suspended particulate matter (RSPM) in the ambient air at the campus and on the roadside. The mean values of PEF variability (amplitude percent mean) in the students living on campus and in the commuters were 5.7 +/- 3.2 and 11 +/- 3.6, respectively (P < .05). Among the commuters, maximum number of subjects showed amplitude percentage mean PEFR at the higher end of variability distribution, as compared to the students living on campus, among whom the majority of subjects fell in the lower ranges of variability distribution. The ambient air quality parameters, namely SO2, NO2, CO, and RSPM were significantly lower on the campus. It can be concluded that long-term periodic exposure to air pollution can lead to increased PEF variability even in healthy subjects. Measurement of PEF variability may prove to be a simple test to measure effect of air pollution in healthy subjects. 相似文献
2.
A 12.5% corn oil-emulsion (COE) was tested as an oral contrast agent for abdominal computed tomography (CT) examinations in 100 patients. The results were compared with those obtained from another group of patients who received a conventional, high-density, oral contrast agent (2-3% iodinated solution). There was no statistically significant difference in the subjects' tolerance to the two agents (P greater than 0.05). There was, however, a significant improvement in image quality with COE (P less than 0.05). Gastrointestinal tract discrimination, and mucosal and mural visualisation was of higher quality with fat density oral contrast medium than with the high-density contrast agent. These data suggest that COE should be considered for routine use as an alternative to conventional high density oral contrast agents in upper abdominal CT. 相似文献
3.
An anatomical study of the facial artery 总被引:9,自引:0,他引:9
N S Niranjan 《Annals of plastic surgery》1988,21(1):14-22
The anatomical variations encountered in the dissection of 50 facial arteries in 25 adult preserved cadavers are presented. The facial artery was symmetrical in 17 of 25 (68%) of the dissections. The facial artery terminated as an angular facial artery in 34 (68%), a lateral nasal vessel in 13 (26%), and a superior labial vessel in 2 (4%); in 1 (2%) the facial artery terminated at the alar base. A longer course was identified in 5 (10%) facial arteries. The use of nasolabial flap (skin, full-thickness, and oral mucosa) raised as an island flap based on the facial artery or one its branches is discussed. 相似文献
4.
Summary Prosthetic materials, such as metals, marlex mesh and methyl methacrylate have been used for stabilization of the chest wall after resection of large areas of rib cage. Such materials are contraindicated in an infected area. A new method of providing a stable chest wall using autogenous tissue is presented. 相似文献
5.
Summary This paper describes a new technique for the division of syndactyly. The commissure is reconstructed by a dorsal trilobed flap and a zig zag incision which produces triangular flaps for the side of the digits. This technique does not require use of a skin graft. Seventeen syndactylies in fourteen children, nine incomplete (six congenital and three secondary to burn) and eight complete syndactylies were treated by this technique. The results after a maximum of twelve months follow-up and the advantages of the technique are discussed.[/ab] 相似文献
6.
7.
8.
The histamine metabolitetele-methylhistamine (t-MH) was identified and measured in crude and purified peritoneal mast cells (MCs). Peritoneal dialysates, peritoneal cells, and purified MCs all containedt-MH in concentrations representing about 0.2% of the corresponding histamine (HA) levels.T-MH levels in crude cells represented about 70% of the total dialysate levels, indicating the presence of extracellular as well as intracellulart-MH.T-MH levels per MC in purified fractions were similar to those of crude fractions, indicating a MC origin for the intracellulart-MH. Histamine methyltransferase activity was not detected in crude or purified MC fractions, and incubations with the monoamine oxidase inhibitor pargyline failed to increase the content or release oft-MH in either fraction, suggesting a very slow or non-existent histamine methylation in MCs. Compound 48/80 produced a temperature-dependent release of HA andt-MH in crude and purified preparations, and Triton X-100 also released both amines. In all cases, the degree of release of both amines was correlated, consistent with a granular origin fort-MH in MCs. The low concentrations oft-MH in MCs do not necessarily indicate a role for MCs in HA metabolism, but suggest thatt-MH may be a valuable marker for non-MC HA. 相似文献
9.
A feasibility study to investigate the use of thin-plate splines to account for prostate deformation
Image registration is an important step in the radiotherapy treatment planning process. It provides a method of fusing different types of diagnostic imaging information. One such application is to combine magnetic resonance spectroscopic images (MRSI) of the prostate with anatomical MRI and/or computed tomography images that are routinely used in the radiation treatment planning of prostate cancer. MRSI provides in vivo information related to the underlying metabolic activity of tissues, and can be related to the presence of cancer. However, the inflated endorectal coil required during MRS imaging poses a potential problem by deforming the prostate when it is filled with approximately 100 cm3 of air during image acquisition. This pushes the prostate superiorly/anteriorly, deforming the prostate and consequently the spectroscopic imaging data in a nonlinear manner. In this application, the coil-deformed MRS images are warped back to a non-deformed state, using a single data set. A nonlinear warping algorithm is presented to achieve this. Results indicate that the algorithm attains an accuracy of 97% (4 cm3 difference) when reproducing the total prostate volume compared to a Radiation Oncologist defined prostate volume. This difference is slightly smaller than the measured intra-operator variance of +/-1.5 cm3 (deflated coil) and the measured algorithm variance of +/-1.0 cm3. Additionally, intraprostatic nodules were used to assess the accuracy of the warping algorithm in regions inside the prostate. While choosing anatomical tie points along the external prostate surface, analysis of the nodules revealed the algorithm accuracy reduced to 63-93%. 相似文献
10.
Aier M Zadeng T Basu D Biswal N Nalini P 《Indian journal of pathology & microbiology》2002,45(3):355-357
A 17 days old male infant, who had features of Down Syndrome, presented with fever, refusal to feed and seizures. He had papular, crusted skin lesions, moderate hepatosplenomegaly and a rapid downhill course. Peripheral blood and bone marrow aspirate showed features of acute leukaemia. Congenital Leukaemia is a rare malignancy associated with a very poor prognosis. Paradoxically, many cases of Congenital Leukaemia, especially in infants with Down Syndrome, show spontaneous remission. 相似文献