全文获取类型
收费全文 | 281083篇 |
免费 | 18705篇 |
国内免费 | 1735篇 |
专业分类
耳鼻咽喉 | 3550篇 |
儿科学 | 6583篇 |
妇产科学 | 5773篇 |
基础医学 | 40054篇 |
口腔科学 | 5516篇 |
临床医学 | 27116篇 |
内科学 | 56159篇 |
皮肤病学 | 5794篇 |
神经病学 | 23795篇 |
特种医学 | 11791篇 |
外国民族医学 | 1篇 |
外科学 | 39099篇 |
综合类 | 3784篇 |
现状与发展 | 6篇 |
一般理论 | 236篇 |
预防医学 | 20261篇 |
眼科学 | 7441篇 |
药学 | 22177篇 |
1篇 | |
中国医学 | 1871篇 |
肿瘤学 | 20515篇 |
出版年
2023年 | 1570篇 |
2022年 | 3775篇 |
2021年 | 7099篇 |
2020年 | 3827篇 |
2019年 | 5907篇 |
2018年 | 7112篇 |
2017年 | 5199篇 |
2016年 | 6493篇 |
2015年 | 8283篇 |
2014年 | 10733篇 |
2013年 | 13795篇 |
2012年 | 20859篇 |
2011年 | 21099篇 |
2010年 | 12049篇 |
2009年 | 10567篇 |
2008年 | 17066篇 |
2007年 | 17413篇 |
2006年 | 16276篇 |
2005年 | 15907篇 |
2004年 | 14584篇 |
2003年 | 13089篇 |
2002年 | 12041篇 |
2001年 | 5544篇 |
2000年 | 4899篇 |
1999年 | 4471篇 |
1998年 | 2734篇 |
1997年 | 2198篇 |
1996年 | 1879篇 |
1995年 | 1794篇 |
1994年 | 1539篇 |
1993年 | 1416篇 |
1992年 | 2225篇 |
1991年 | 2167篇 |
1990年 | 1888篇 |
1989年 | 1731篇 |
1988年 | 1650篇 |
1987年 | 1509篇 |
1986年 | 1426篇 |
1985年 | 1375篇 |
1984年 | 1200篇 |
1983年 | 1084篇 |
1982年 | 1093篇 |
1981年 | 979篇 |
1980年 | 871篇 |
1979年 | 885篇 |
1978年 | 753篇 |
1977年 | 735篇 |
1976年 | 632篇 |
1974年 | 635篇 |
1973年 | 586篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
123I-MIBG myocardial scintigraphy as a noninvasive screen for the diagnosis of coronary artery spasm
Jong-Won Ha Jong-Doo Lee Yangsoo Jang Namsik Chung June Kwan Se-Joong Rim Young-Joon Lee Won-Heum Shim Seung-Yun Cho Sung-Soon Kim 《Journal of nuclear cardiology》1998,5(6):591-597
Background It has been suggested that the sympathetic nervous system might play an important role in the development of coronary artery
spasm. However, no cardiac imaging modality has been able to demonstrate abnormal sympathetic innervation in patients with
coronary artery spasm. The purpose of this study was to assess the presence and location of abnormal sympathetic innervation
using iodine 123-metaiodobenzylguanidine (123I-MIBG) single photon emission computed tomography (SPECT) and to evaluate the clinical efficacy of 123I-MIBG SPECT as a noninvasive screening test in patients with coronary artery spasm.
Methods and Results Coronary arteriography and a provocative test with intravenous administration of ergonovine maleate were performed in 26 patients
(20 men, 6 women, mean age 48.2±12.0 years, range 20 to 67 years) who were suspected of having a coronary artery spasm. The
subjects were divided into 2 groups: group 1 (n=18) comprised subjects with negative provocative provocative test result,
and group 2 (n=8) comprised subjects with negative provocative test results. Ten healthy subjects served as controls. No abnormal
MIBG uptake was observed in the control subjects. Abnormal sympathetic nervous innervation using 123I-MIBG SPECT was observed either as a reduced uptake or a defective pattern in the perfused areas in 13 of the 18 regions
supplied by vessels of ergonovine-induced vasospasm. Normal sympathetic innervation, as evidenced by normal 123I-MIBG uptake, was noted in all of the 60 segments of normal vessel territories. Reduced uptake of 123I-MIBG was not detected in the perfused areas of 5 vasospasm-induced vessels (perfusion territory of left anterior descending
coronary artery [LAD] and the right coronary artery [RCA] in 2 and 3 patients, respectively). The sensitivity and specificity
of 123I-MIBG for detection of coronary artery spasm were 72.2% (95% confidence interval, [CI] 55% to 89%) and 100%, respectively.
The positive predictive and negative predictive values were 100% and 92.3% (95% CI 91% to 93%), respectively.
Conclusion
123I-MIBG SPECT is a feasible method to evaluate noninvasively and localize the territories of coronary arteries with spasm.
Invasive diagnostic coronary arteriography with ergonovine provocation test may be unnecessary for diagnosis of coronary artery
spasm in patients with typical resting pain, negative exercise test or normal thallium perfusion scan results, but showing
abnormalities in 123I-MIBG SPECT.
Presented in part at the European Association of Nuclear Medicine Congress, September 1996, Copenhagen, Denmark. 相似文献
992.
We studied 14 eyes of 14 patients undergoing argon laser peripheral iridotomy for occludable (narrow) anterior chamber angles. Preoperative and postoperative pachymetry and corneal endothelial cell counts by specular microscopy were obtained centrally and in both the treated and nontreated superior quadrants. No significant differences were found between preoperative and postoperative measurements of corneal thickness and endothelial cell counts in any area. 相似文献
993.
Arne T. Hstmark Einar Lystad Einar Jebens Jan Skramstad Paul Fryen 《Basic & clinical pharmacology & toxicology》1998,83(1):29-35
Abstract: Chlorinated fatty acids represent a major fraction of extractable, organically bound chlorine in fish. After dietary intake such fatty acids may be transferred from the mother to the foetus through the placenta, and via breast milk to the child. In the present work we have studied the effect of chlorinated oleic acid on the growth of three widely differing types of cells in culture. Chlorinated oleic acid inhibited growth of Human Microvascular Endothelial Cells (HMVEC), Immortilized Human Kidney Epithelial (IHKE) cells, and human Hepatoma cells (HepG2). The order of potency was: HMVEC > IHKE > HepG2. Vitamin E counteracted the inhibitory effect of chlorinated oleic acid on HepG2 cells, but did not significantly affect the fatty acid effect on HMVEC or IHKE. Defatted serum albumin stimulated the growth of HMVEC and IHKE. With HMVEC there was no major interaction between the effect of albumin and chlorinated oleic acid on cell growth. In contrast, with IHKE albumin at low concentration abolished the growth inhibiting effect of chlorinated oleic acid and appreciably counteracted growth inhibition by the fatty acid of HepG2 . We conclude that the growth modulation by chlorinated oleic acid and its interaction with vitamin E and albumin are cell specific. 相似文献
994.
995.
Joseph C. Gretzula D.O. Osmar Hevia B.S. Lawrence S. Shachner M.D. John H. DiLiberti M.D. † R. H. A. Ruvalcaba M.D. ‡ James R. Schimshock M.D. § Richard G. Weleber M.D. Fahed Halal M.D. # Mark H. Lipson M.D. Bruce Blumberg M.D. †† Paul J. Weber M.D. 《Pediatric dermatology》1988,5(1):28-32
In 1980 a syndrome was first described in two adult males, consisting of macrocephaly, pigmented macules on the glans and shaft of the penis, and hamartomatous intestinal polyps. Since then, 10 additional cases have been identified. Herein, we present two new cases and review the cutaneous manifestations as well as additional features in patients with the Ruvalcaba-Myhre-Smith syndrome. 相似文献
996.
L Gourley S W Duffy H P Lee A M Walker N E Day 《European journal of clinical nutrition》1988,42(4):333-343
A survey of 40 Singapore Chinese households was performed, obtaining information on major perishable foods purchased for home consumption in the previous week, extent of home consumption (eating in), household dietary habits and housing type, the last as a measure of affluence. Eating out was very common: nine (23 per cent) households ate less than 50 per cent of meals at home. Excluding these nine households, consumption and habits were compared between more affluent and less affluent households. The more affluent households purchased more red meat/offal (P = 0.001), poultry (P = 0.002), vegetables other than green leafy (P = 0.04), fruit (P = 0.007) and eggs (P = 0.04); they also differed significantly in various dietary habits. Significant differences were also observed between English-speaking and Chinese-speaking households. The results suggest that increasing affluence may have brought about substantial dietary change in Singapore, thus meriting further study of the role of diet in changing disease patterns in Singapore. 相似文献
997.
Sharon C. Reimold M.D. Sary F. Aranki M.D. Eduardo S. Caguioa M.D. Scott D. Solomon M.D. Vladimir Birjiniuk M.D. Lawrence H. Cohn M.D. Richard T. Lee M.D. 《Journal of cardiac surgery》1994,9(3):304-313
Objectives: The purpose of this study was to determine if a device placed externally around the aortic root decreases regurgitant flow in acute aortic regurgitation. Background: Aortic regurgitant flow is dependent on central aortic pressure and the aortic root and leaflet geometry. It may be possible to decrease aortic regurgitant severity by reducing aortic root size or dimension changes. Methods: Aortic regurgitation was created in eight calf heart specimens suspended in a continuous flow system. Retrograde and antegrade aortic flow and distending aortic pressure were measured at baseline and after placement of an external aortic device at the level of the aortic annulus. In two additional specimens, the incompetent aortic valve was visualized fiberoptically before and after placement of the external device. Acute aortic regurgitation was created surgically in four live calves by excising a portion of the aortic leaflets. Antegrade and retrograde flow, left ventricular pressure, and central aortic pressure were measured at baseline, after creation of aortic regurgitation, and after placement of the external device. Results: In the in vitro calf specimens, regurgitant flow decreased from 46.9 cc/sec to 15.1 cc/sec (66.0%± 21.8% decrease) after placement of the external device (p < 0.001). The regurgitant orifice area decreased from 0.13 ± 0.04 cm2 to 0.04 ± 0.02 cm2 after device placement (p < 0.001). Antegrade flow was reduced to a smaller extent (20.0%± 19.2% decrease) by the device (p < 0.05). Placement of the device around the aorta resulted in improved coaptation of the leaflets with a marked reduction in defect size by endoscopic visualization. Use of the external aortic device was associated with improvement in aortic regurgitant severity in three of four calves with surgically created aortic regurgitation. Concluslons: In these preliminary studies, acute experimental aortic regurgitant severity is decreased by the use of an external aortic device, probably due to reduction in aortic annular dimension changes and improved aortic leaflet apposition. Further studies are needed to determine the effectiveness of this device in chronic aortic regurgitation. (J Card Surg 1994;9:304–313) 相似文献
998.
999.
Rapid determination of trisomy 18 parental origin using fluorescent PCR and small tandem repeat markers: case reports 总被引:3,自引:0,他引:3
Ian Findlay Tamás Tóth Paul Matthews Tamás Marton Philip Quirke Zoltán Papp 《Clinical genetics》1998,53(2):92-95
Trisomy 18 is the second most common genetic defect after trisomy 21, almost 90% of which are due to additional chromosome from the mother. The parental origin of the additional chromosome can, if required, be determined by two methods: karyotyping, which takes several weeks; or, more recently, by polymerase chain reaction (PCR) which is often problematic. Fluorescent PCR of small tandem repeats (STRs) can determine the parental origin in the majority of cases within 5 h. Although the incidence of paternal origin is known for both trisomy 21 and trisomy 18, this technique can rapidly determine the parental origin in cases where there is insufficient samples to perform conventional tests. Determining parental origin by these methods may also have clinical significance in the diagnosis of chromosomal translocations or in the diagnosis of genetic disease using linkage analysis. 相似文献
1000.
Stephen F. Quinn Joseph J. Haberman Steven W. Fitzgerald Paul D. Traughber Rod I. Belkin William T. Murray 《Journal of magnetic resonance imaging : JMRI》1994,4(2):169-172
The evaluation of loose bodies in the elbow is usually done by means of clinical examination, radiography, and postarthrographic computed tomography (CT). The authors review their experience with magnetic resonance (MR) imaging in place of postarthrographic CT for the evaluation of loose bodies in the elbow. The prospective interpretation of MR studies of the elbow in 20 patients was compared with arthroscopic findings. All elbows were imaged in multiple planes with thin sections, surface coils, and combinations of T1, T2, and proton-density weighting. The sensitivity for showing loose bodies with MR imaging was 100%, and the specificity was 67%. Because this was a nonblinded study, the results are biased and caution must be used when extrapolating these results to the general population. In this limited experience, MR imaging has reliably shown loose bodies in the elbow, and in the authors' institutions has replaced postarthrographic CT for that purpose. 相似文献