全文获取类型
收费全文 | 5237篇 |
免费 | 245篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 42篇 |
儿科学 | 343篇 |
妇产科学 | 115篇 |
基础医学 | 771篇 |
口腔科学 | 132篇 |
临床医学 | 364篇 |
内科学 | 912篇 |
皮肤病学 | 433篇 |
神经病学 | 280篇 |
特种医学 | 77篇 |
外科学 | 458篇 |
综合类 | 108篇 |
一般理论 | 1篇 |
预防医学 | 326篇 |
眼科学 | 238篇 |
药学 | 546篇 |
中国医学 | 21篇 |
肿瘤学 | 331篇 |
出版年
2023年 | 50篇 |
2022年 | 172篇 |
2021年 | 247篇 |
2020年 | 130篇 |
2019年 | 163篇 |
2018年 | 178篇 |
2017年 | 129篇 |
2016年 | 166篇 |
2015年 | 158篇 |
2014年 | 208篇 |
2013年 | 261篇 |
2012年 | 369篇 |
2011年 | 358篇 |
2010年 | 232篇 |
2009年 | 196篇 |
2008年 | 250篇 |
2007年 | 235篇 |
2006年 | 256篇 |
2005年 | 236篇 |
2004年 | 201篇 |
2003年 | 187篇 |
2002年 | 202篇 |
2001年 | 86篇 |
2000年 | 100篇 |
1999年 | 79篇 |
1998年 | 37篇 |
1997年 | 34篇 |
1996年 | 32篇 |
1995年 | 15篇 |
1994年 | 20篇 |
1993年 | 22篇 |
1992年 | 41篇 |
1991年 | 30篇 |
1990年 | 51篇 |
1989年 | 46篇 |
1988年 | 39篇 |
1987年 | 31篇 |
1986年 | 28篇 |
1985年 | 26篇 |
1984年 | 26篇 |
1983年 | 20篇 |
1982年 | 15篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 14篇 |
1978年 | 12篇 |
1977年 | 18篇 |
1976年 | 7篇 |
1974年 | 9篇 |
1971年 | 7篇 |
排序方式: 共有5498条查询结果,搜索用时 0 毫秒
31.
32.
33.
The effect of some anesthetic drugs on intraocular pressure (IOP) was studied in 120 normal healthy patients undergoing non-ophthalmic surgical procedures. IOP rose significantly following the injection of succinylcholine (SCh) alone, or when such injection had been preceded by a pretreatment with a "self-taming" dose of SCh or d-tubocurarine (d-Tc). Though the rise in IOP after diazepam pretreatment was significant, the magnitude was lower than that observed in the groups pretreated with the other two agents. Halothane brought the IOP down faster and lower than ether. SCh is unsafe for intubation for the administration of general anesthesia in cases involving penetrating ocular injuries. It can, however, be used safely for routine ophthalmic surgery, providing that 8 minutes are allowed to elapse between injection and corneal or scleral incision. Halothane is preferred to ether, since the former lowers IOP faster and in a greater amount than the latter. 相似文献
34.
Assay of hexosaminidase A and B enzymes in four cases with developmental regression and cherry red spot on fundus examination
confirmed that three cases had Tay-Sachs disease, and one case had Sandhoff disease. Prenatal diagnosis was carried out by
hexosaminidase enzyme assay in amniotic fluid and cells in one family, and chorionic villus sample in the second family. The
fetus was diagnosed to be unaffected in one, and affected in the other family. Assay of hexosaminidase A and B is useful for
specific diagnosis of GM2 gangliosidosis, and for prenatal diagnosis to reduce the burden of these disorders. 相似文献
35.
Increased expression of transferrin receptors and iron in amoeboid microglial cells in postnatal rats following an exposure to hypoxia 总被引:2,自引:0,他引:2
This study was aimed to ascertain the effects of hypoxia on regulation of iron in the brain of newborn rats. At 3 h and 1 day after hypoxic exposure transferrin receptor expression as detected immunohistochemically with the antibody OX-26, and the iron content as shown by Perls' staining of amoeboid microglial cells was markedly increased. The induced changes, however, were not evident at 10 min and in longer surviving rats killed at 3 and 7 days. It is suggested that the upregulation of transferrin receptor expression coupled with iron uptake by amoeboid microglial cells in the periventricular regions is a protective mechanism to facilitate the sequestration of excess iron that may have been released either from the iron-rich oligodendrocytes, or accumulated due to a disruption of its normal transportation following the hypoxic insult. This would help protect the brain from harmful effects of iron. 相似文献
36.
37.
Objective
To determine if saphenous vein required for coronary bypass could be quickly, easily and safely removed with a minimally invasive technique.Design
A consecutive series.Setting
A university centre.Material and Methods
In cadavers, a standard mediastinoscope was used to remove segments of the greater saphenous vein. Thigh segments, superior leg segments and ankle segments were removed. Fifteen minutes were allowed for removal of a segment.Results
Segments of vein 15 to 17 cm long could be removed. One segment could not be removed within 15 minutes. Thigh segments were easy to remove, calf segments were the most difficult. There were no avulsed side branches. All incisions were less than 5 cm long.Conclusions
Saphenous vein can be harvested quickly and safely by a minimally invasive method. Lower extremity complications may be reduced and long-term patency improved with this in-situ technique of vein removal. 相似文献38.
Kamaljit Kaur Nishi Sonkhya A. S. Bapna 《Indian journal of otolaryngology and head and neck surgery》2003,55(1):21-24
Traditionally, it has been accepted that chronic suppurative Otitis media is associated with a breakdown in meekanical conduction
of sound leading to conductive hearing loss, On;the contrary, there are two schools of thought when it come, to the issue
of cpchlear involvement leading to sensorineural hearing loss (SNIIL) in chronic suppura the Otitis media. The present study
was undertaken to find out whether a sensorineural component exists in hearing loss associated with chronic suppurative otitis
media, A sample of 100 patients of unilateral chronic suppurative otitis media was selected for the Study and their bone conduction
thresholds Mere analyzed in relation to the duration of disease using audiometric data. A 24 per cent incidence of sensoineural
hearing loss was found in this series, garticularly involving the higher frequencies. Moreover, the incidence of sensorineural
hearing loss progressively increased with the increase in duration of chonic suppurative Ouns meadia 相似文献
39.
Gurmeet Kaur Dorina Belotti Angelika M Burger Kirsten Fisher-Nielson Patrizia Borsotti Elena Riccardi Jagada Thillainathan Melinda Hollingshead Edward A Sausville Raffaella Giavazzi 《Clinical cancer research》2004,10(14):4813-4821
PURPOSE: The purpose of this study was to investigate the antiangiogenic properties of 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin (17-DMAG; NSC707545), a water-soluble benzoquinone ansamycin. EXPERIMENTAL DESIGN: The activity of 17-DMAG, in vivo, was evaluated for inhibition of fibroblast growth factor (FGF)-2-induced angiogenesis in s.c. implanted Matrigel in mice. In vitro, the activity of 17-DMAG on endothelial cells (human umbilical vein endothelial cells; HUVEC) was tested in FGF-2; and vascular endothelial growth factor (VEGF)-induced proliferation and apoptosis, motility, and extracellular matrix invasion; and on the alignment of capillary like structures in Matrigel. The protein level of heat shock protein (Hsp)90 and client proteins was examined by Western blot in FGF-2 and VEGF-stimulated HUVEC. RESULTS: Daily oral administration of 17-DMAG affected the angiogenic response in Matrigel in a dose-dependent manner. The hemoglobin content in the Matrigel implants was significantly inhibited, and the histological analysis confirmed a decrease of CD31(+) endothelial cells and of structures organized in cord and erythrocyte-containing vessels. In vitro, the compound inhibited dose-dependently the migration and the extracellular matrix-invasiveness of HUVEC and their capacity to form capillary like structures in Matrigel. 17-DMAG treatment also inhibited FGF-2 and VEGF-induced HUVEC proliferation and resulted in apoptosis. Accordingly, the expression of Hsp90 direct client proteins (pAkt and c-Raf-1) or their downstream substrates including pERK was also affected. 17-DMAG consistently increased the expression of Hsp70. Throughout the study similar results were obtained with 17-allylamino-17-demethoxygeldanamycin (17-AAG; NSC330507), the analog compound currently undergoing clinical trials. CONCLUSIONS: We show that the Hsp90 targeting agents 17-DMAG and 17-AAG inhibit angiogenesis. The strong effects on endothelial cell functions, in vitro, indicate that the antiangiogenic activity of 17-DMAG/17-AAG could also be due to a direct effect on endothelial cells. The oral bioavailability of 17-DMAG might be of advantage in investigating the potential of this compound in clinical trials with antiangiogenic as well as antiproliferative endpoints. 相似文献
40.
Marilyn A Roubidoux Judith Salmon Kaur Kent A Griffith Barbara Stillwater Paul Novotny Jeff Sloan 《Cancer epidemiology, biomarkers & prevention》2003,12(10):1081-1086
The purpose is to determine breast cancer risk factors and correlates of mammographic parenchymal patterns among Alaska Native women. A retrospective review was performed of mammograms and mammogram records among 528 sequential screening mammogram examinations performed in Anchorage, Alaska. Mammogram density was classified by American College of Radiology (Breast Imaging Reporting and Data System) density patterns 1-4 (fat-->dense) and by percent density. Clinical data, including risk factors, ethnic group (Indian, Aleut, or Eskimo), and smoking status were obtained. Results were analyzed by univariate and multivariate analyses. Of 528 women, 164 were Indian, 155 were Aleut, and 209 were Eskimo. Mean age at first birth was lower and parity higher compared with published data in white women. Breast cancer risk factors were similar across ethnic groups. In multivariate analysis, patient age, parity, hormone replacement therapy, hysterectomy, and history of biopsy were associated, and smoking was not associated with density scores. Aleut and Indian women were less likely to have high-density mammograms than were Eskimo women (P = 0.0448). No significant differences were found between ethnic group for conventional breast cancer risk factors. Mammogram density was associated with age at screening, parity, hormone replacement therapy, hysterectomy, history of biopsy, and ethnicity but not smoking status. Eskimo women had higher mammogram density than Aleuts or Indians. 相似文献