全文获取类型
收费全文 | 19275篇 |
免费 | 1159篇 |
国内免费 | 148篇 |
专业分类
耳鼻咽喉 | 220篇 |
儿科学 | 508篇 |
妇产科学 | 707篇 |
基础医学 | 2136篇 |
口腔科学 | 570篇 |
临床医学 | 1584篇 |
内科学 | 3796篇 |
皮肤病学 | 398篇 |
神经病学 | 913篇 |
特种医学 | 727篇 |
外国民族医学 | 11篇 |
外科学 | 3409篇 |
综合类 | 350篇 |
现状与发展 | 2篇 |
一般理论 | 11篇 |
预防医学 | 1644篇 |
眼科学 | 544篇 |
药学 | 1775篇 |
中国医学 | 138篇 |
肿瘤学 | 1139篇 |
出版年
2023年 | 225篇 |
2022年 | 659篇 |
2021年 | 1144篇 |
2020年 | 625篇 |
2019年 | 778篇 |
2018年 | 1045篇 |
2017年 | 611篇 |
2016年 | 636篇 |
2015年 | 653篇 |
2014年 | 916篇 |
2013年 | 1066篇 |
2012年 | 1540篇 |
2011年 | 1686篇 |
2010年 | 959篇 |
2009年 | 695篇 |
2008年 | 980篇 |
2007年 | 984篇 |
2006年 | 903篇 |
2005年 | 869篇 |
2004年 | 753篇 |
2003年 | 700篇 |
2002年 | 621篇 |
2001年 | 147篇 |
2000年 | 121篇 |
1999年 | 97篇 |
1998年 | 82篇 |
1997年 | 74篇 |
1996年 | 74篇 |
1995年 | 66篇 |
1994年 | 61篇 |
1993年 | 51篇 |
1992年 | 51篇 |
1991年 | 59篇 |
1990年 | 59篇 |
1989年 | 54篇 |
1988年 | 52篇 |
1987年 | 52篇 |
1986年 | 39篇 |
1985年 | 39篇 |
1984年 | 40篇 |
1983年 | 39篇 |
1982年 | 34篇 |
1981年 | 24篇 |
1980年 | 22篇 |
1978年 | 16篇 |
1977年 | 14篇 |
1976年 | 18篇 |
1975年 | 14篇 |
1974年 | 13篇 |
1973年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
11.
Mokhtar Elhakim Magdy Nafie Khalaf Mahmoud Azza Atef 《Journal canadien d'anesthésie》2002,49(9):922-926
PURPOSE: The combination of antiemetic drugs could be a solution to prevent severe postoperative nausea and vomiting (PONV). The aim of this randomized double blind, dose-ranging study was to determine the minimum single effective dose of dexamethasone combined with ondansetron for the prevention of PONV in patients undergoing laparoscopic cholecystectomy. METHODS: One hundred eighty patients were allocated randomly to one of six groups to receive saline (P group), ondansetron 4 mg (O group), or ondansetron 4 mg and dexamethasone at doses of 2 mg (OD2 group), 4 mg (OD4 group), 8 mg (OD8 group), and 16 mg (OD16 group). A standardized general anesthetic was used. All episodes of PONV during the intervals of zero to six hours, 6-12 hr and 12-24 hr after surgery were evaluated using a numeric scoring system. Mean visual analogue scale pain scores at rest and on movement, the time to first demand of analgesia, total analgesic consumption in 12 hr epochs, duration of hospital stay, and side effects were recorded. RESULTS: The incidence of PONV in the OD8 (16%) and OD16 (16%) groups was lower than in the 83% (P < 0.001) and O groups (50%) at the 12-24 hr epoch (P < 0.05). There were no differences in antiemetic effect between the O, OD2 and OD4 groups and between the OD8 and OD16 groups. Pain scores, total analgesic consumption, duration of hospital stay and side effects were similar among groups. CONCLUSION: Our results suggest that 8 mg is the minimum dose of dexamethasone that, combined with ondansetron 4 mg will effectively prevent PONV in patients undergoing laparoscopic cholecystectomy. 相似文献
12.
The influence of protein solubilisation, conformation and size on the burst release from poly(lactide-co-glycolide) microspheres. 总被引:5,自引:0,他引:5
Gayle Duncan Thomas J Jess Farahidah Mohamed Nicholas C Price Sharon M Kelly Christopher F van der Walle 《Journal of controlled release》2005,110(1):34-48
Encapsulation of proteins in poly(lactide-co-glycolide) microspheres via emulsion is known to cause insoluble protein aggregates. Following protein emulsification and encapsulation in PLGA microspheres, we used circular dichroism to show that the recoverable soluble protein fraction also suffers subtle conformational changes. For a panel of proteins selected on the basis of molecular size and structural class, conformational stability measured by chemical denaturation was not indicative of stability during emulsion-encapsulation. Partial loss of structure was observed for alpha-helical proteins released from freeze-dried microspheres in aqueous buffer, with dramatic loss of structure for a beta-sandwich protein. The addition of sucrose (a lyoprotectant) did not prevent the loss of protein conformation upon encapsulation. Therefore, the conformational changes seen for the released soluble protein fraction originates during emulsification rather than microsphere freeze-drying. Analysis of the burst release for all proteins in buffer containing denaturant or surfactant showed that the degree of protein solubilisation was the dominant factor in determining the initial rate and extent of release. Our data for protein release into increasing concentrations of denaturing buffer suggest that the emulsion-denatured protein fraction remains insoluble; this fraction may represent the protein loss encountered upon comparison of protein encapsulated versus protein released. 相似文献
13.
14.
Youness El harrech Hassan Jira Jaouad Chafiki Mohamed Ghadouane Ahmed Ameur Mohamed Abbar 《Actas urologicas espa?olas》2009,33(1):93-96
Nutcracker syndrome is caused by compression of the left renal vein between the aorta and the superior mesenteric artery where it passes in the fork formed at the bifurcation of these arteries. The phenomenon results in left renal venous hypertension. The syndrome is manifested by left flank and abdominal pain, with or without unilateral haematuria. The nutcracker syndrome has been treated in various ways. We report one case of the syndrome and discuss the place of surveillance in its management. 相似文献
15.
Synthesis of 2-(Hydrazinocarbonylthio)-acetic Acids and Cyclization to 3-Aminothiazolidine-2,4-diones N-mono- or N,N-disubstituted hydrazines are reacted with carbonyl sulfide, triethylamine and halogenoacetic acids to yield the 2-(hydrazinocarbonylthio) acetic acids 1 , which are cyclizised to yield the 3-aminothiazolidine-2,4-diones 2 by dicyclohexylcarbodiimide. 相似文献
16.
I Ilardi S C Shiddo H H Mohamed C Mussa A S Hussein C S Mohamed K Bile A Sebastiani C Bianchini S Sanguigni 《Transactions of the Royal Society of Tropical Medicine and Hygiene》1987,81(2):336-338
About 85% of the population of two Somali communities harboured soil-transmitted intestinal nematodes and/or protozoa. The commonest parasite (75% in the Lafoole institution and 59% in the Afgoye institution) was Trichuris trichiura. Mixed infections were common. The source of infection is contaminated fields around dwelling quarters, because of indiscriminate defaecation. One of the factors responsible for the higher incidence of hookworm in Lafoole (45%) compared with Afgoye (1.5%) may be the different soil character of the surrounding fields. 相似文献
17.
18.
19.
20.
S H Faro A R Turtz R A Koenigsberg F B Mohamed C Y Chen H Stein 《AJNR. American journal of neuroradiology》1997,18(8):1588
The MR imaging features of a paraganglioma of the cauda equina with associated spinal cord cysts are presented. MR imaging showed the tumor to be isointense with the spinal cord on all pulse sequences and to enhance homogeneously. The intramedullary cysts had increased signal intensity on proton density- and T2-weighted images, and involved the cervical and thoracic regions. 相似文献