全文获取类型
收费全文 | 16725篇 |
免费 | 1147篇 |
国内免费 | 403篇 |
专业分类
耳鼻咽喉 | 190篇 |
儿科学 | 380篇 |
妇产科学 | 426篇 |
基础医学 | 2288篇 |
口腔科学 | 250篇 |
临床医学 | 1783篇 |
内科学 | 3113篇 |
皮肤病学 | 395篇 |
神经病学 | 1044篇 |
特种医学 | 712篇 |
外国民族医学 | 1篇 |
外科学 | 1823篇 |
综合类 | 1090篇 |
现状与发展 | 4篇 |
一般理论 | 2篇 |
预防医学 | 1443篇 |
眼科学 | 340篇 |
药学 | 1246篇 |
8篇 | |
中国医学 | 444篇 |
肿瘤学 | 1293篇 |
出版年
2024年 | 39篇 |
2023年 | 166篇 |
2022年 | 366篇 |
2021年 | 533篇 |
2020年 | 392篇 |
2019年 | 439篇 |
2018年 | 584篇 |
2017年 | 458篇 |
2016年 | 483篇 |
2015年 | 509篇 |
2014年 | 645篇 |
2013年 | 800篇 |
2012年 | 1267篇 |
2011年 | 1426篇 |
2010年 | 722篇 |
2009年 | 549篇 |
2008年 | 945篇 |
2007年 | 1025篇 |
2006年 | 901篇 |
2005年 | 1081篇 |
2004年 | 944篇 |
2003年 | 899篇 |
2002年 | 650篇 |
2001年 | 333篇 |
2000年 | 389篇 |
1999年 | 295篇 |
1998年 | 147篇 |
1997年 | 130篇 |
1996年 | 123篇 |
1995年 | 111篇 |
1994年 | 96篇 |
1993年 | 69篇 |
1992年 | 68篇 |
1991年 | 70篇 |
1990年 | 65篇 |
1989年 | 70篇 |
1988年 | 49篇 |
1987年 | 45篇 |
1986年 | 49篇 |
1985年 | 38篇 |
1984年 | 27篇 |
1983年 | 29篇 |
1982年 | 20篇 |
1981年 | 21篇 |
1980年 | 16篇 |
1978年 | 13篇 |
1974年 | 23篇 |
1973年 | 12篇 |
1971年 | 12篇 |
1970年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
P Ia Filiptsev Ia G Mo?siuk Iu V Luk'ianov 《Vestnik khirurgii imeni I. I. Grekova》1989,143(11):36-38
The work presents an experience with 84 operations of making nonstandard arteriovenous fistulas in 75 patients using autovenous transplants, polytetrafluorethylene prosthesis and home bioprostheses from human umbilical veins made at plant "Sever". Results of the operations were followed-up during 3 years. It was shown that arteriovenous fistulas made of plastic materials generally have a higher level of complications and shorter terms of functioning as compared with ordinary fistulas. Nevertheless, using nonstandard fistulas is justified in a certain category of patients. 相似文献
52.
53.
P. J. Vaitkus Dr K. W. Johnston R. L. Bondar F. Stein P. A. J. Bascom Ly Mo M. Kassam L. C. Chadwick J. Mehi R. S. C. Cobbold 《Medical & biological engineering & computing》1990,28(4):306-311
During space flights, several clinical syndromes may be the result of changes in cerebral circulation. The purpose of the
paper is to describe the development and initial evaluation of a system for recording, processing and displaying transcranial
Doppler ultrasound (TCD) waveforms from the middle cerebral artery (MCA) in microgravity. Volunteers were repeatedly subjected
to 15–20 s intervals of microgravity (‘near zero gravity’) during flights on the KC-135 military aircraft. Continuous TCD
recordings from the MCA were stored on magnetic tape. The paper describes the system that was developed to digitise the Doppler
ultrasound data and markers that corresponded to the various levels of microgravity, obtain the maximum and mean Doppler waveforms,
identify the waveforms and quantify them. The results demonstrate the feasibility of making TCD recordings in a microgravity
environment and illustrate excellent performance of the system and its ease of operation. Quantitative waveform analysis of
the recordings from the first subject studied in the supine position showed statistically significant changes in MCA velocity
waveforms during microgravity. 相似文献
54.
Using the peroxidase-antiperoxidase (PAP) technique it could be established that a variety of nerve cells of human Pons and Medulla oblongata contain proctolin-like material. These neurons belong to the Nuc. olivaris caudalis, Nuc. originis n. hypoglossi, Nuc. raphes dorsalis and the Nuc. ambiguus. Furthermore, proctolin immunoreactive peptide was found to be contained in certain fiber systems (Lemniscus medialis and fiber tracts near the Raphe). 相似文献
55.
V Ghe?ie G Mo?a M A Dobre-Ghe?ie M Laky A Olinescu S Dima I Moraru J Sj?quist 《Molecular immunology》1986,23(4):377-384
The monovalent V-1 fragment of protein A (fSpA) with a mol. wt of 13,000 obtained from an u.v. mutant of Staphylococcus aureus Cowan I strain was proved to be able to modulate significantly some of the effector functions of IgG, such as complement fixation, catabolism, attachment to Fc receptors and antibody-dependent cell-mediated cytotoxicity. Moreover fSpA-like protein A obtained from the A676 strain is mitogenic and enhances NK activity of human peripheral lymphocytes. The efficiency of fSpA was found to be lower than that of protein A with regard to its ability to inhibit complement fixation, EA rosette formation and antibody-dependent cell-mediated cytotoxicity. Both protein A and fSpA had the same efficiency in activation of the complement system after reaction with human or guinea pig IgG, and in increasing the IgG catabolism. Unlike fSpA the monovalent B fragment of protein A (with mol. wt of 7000) was not able to inhibit EA rosette formation and antibody-dependent cell-mediated cytotoxicity. The results recommend fSpA, substituting for protein A, as a molecular probe for the investigation of IgG antibody and lymphocyte effector functions. 相似文献
56.
Biochemical characterization of simian foamy virus type I 总被引:2,自引:0,他引:2
Cavalieri F. Rhodes-Feuillette A. Benzair A. B. Emanoïl-Ravicovitch R. Peries J. 《Archives of virology》1981,68(3-4):197-202
Summary Simian syncitium-forming (foamy) virus type I (SFV1) was characterized biochemically. RNA was extracted from purified virus either with 0.1 per cent SDS or by the standard phenol-chloroform method. By both techniques a main component of 65–70S was found. Denaturation of the 65–70S RNA by heat resulted in a shift of the sedimentation coefficient mainly to a 30–35S component. Electrophoresis on a composite polyacrylamide gel demonstrated the existence of three minor RNA's: 8S, 5S and 4S respectively. PAGE-SDS analysis of disrupted purified virions enabled the separate migration of five viral proteins and the identification of two main proteins: a 30 kd polypeptide and a 70 kd polypeptide.With 4 Figures 相似文献
57.
Jinyi Yuan Biwen Mo Zhuang Ma Yuan Lv Shih-Lung Cheng Yanping Yang Zhaohui Tong Renguang Wu Shenghua Sun Zhaolong Cao Jufang Wu Demei Zhu Liwen Chang Yingyuan Zhang 《Journal of microbiology, immunology, and infection》2019,52(1):35-44
Background/Purpose
Nemonoxacin is a novel nonfluorinated quinolone with excellent in vitro activity against most pathogens in community-acquired pneumonia (CAP), especially Gram-positive isolates. The purpose of this study was to assess the efficacy and safety of nemonoxacin compared with levofloxacin in patients with CAP.Methods
A phase 3, multicenter, randomized (2:1) controlled trial was conducted in adult CAP patients receiving nemonoxacin 500 mg or levofloxacin 500 mg orally once daily for 7–10 days. Clinical, microbiological response and adverse events were assessed. Non-inferiority was determined in terms of clinical cure rate of nemonoxacin compared with that of levofloxacin in a modified intention-to-treat (mITT) population. NCT registration number: NCT01529476.Results
A total of 527 patients were randomized and treated with nemonoxacin (n = 356) or levofloxacin (n = 171). The clinical cure rate at test-of-cure visit was 94.3% (300/318) for nemonoxacin and 93.5% (143/153) for levofloxacin in the mITT population [difference (95% CI), 0.9% (?3.8%, 5.5%)]. The microbiological success rate was 92.1% (105/114) for nemonoxacin and 91.7% (55/60) for levofloxacin in the bacteriological mITT population [difference (95% CI), 0.4% (?8.1%, 9.0%)]. The incidence of adverse events (AEs) was comparable between nemonoxacin (33.1%, 118/356) and levofloxacin (33.3%, 57/171) (P > 0.05).Conclusion
Nemonoxacin 500 mg once daily for 7–10 days is as effective and safe as levofloxacin for treating adult CAP patients in terms of clinical cure rates, microbiological success rates, and safety profile.ClinicalTrials.gov identifier: NCT01529476. 相似文献58.
Myung Ha Yoon Kyung Deok Park Hyung Gon Lee Woong Mo Kim Tae Hoon An Yeo Ok Kim Lan Ji Huang Cui Jin Hua 《Journal of Korean medical science》2008,23(6):1033-1038
The possible characteristics of spinal interaction between sildenafil (phosphodiesterase 5 inhibitor) and morphine on formalin-induced nociception in rats was examined. Then the role of the opioid receptor in the effect of sildenafil was further investigated. Catheters were inserted into the intrathecal space of male Sprague-Dawley rats. For induction of pain, 50 µL of 5% formalin solution was applied to the hind-paw. Isobolographic analysis was used for the evaluation of drug interaction between sildenafil and morphine. Furthermore, naloxone was intrathecally given to verify the involvement of the opioid receptor in the antinociception of sildenafil. Both sildenafil and morphine produced an antinociceptive effect during phase 1 and phase 2 in the formalin test. The isobolographic analysis revealed an additive interaction after intrathecal delivery of the sildenafil-morphine mixture in both phases. Intrathecal naloxone reversed the antinociception of sildenafil in both phases. These results suggest that sildenafil, morphine, and the mixture of the two drugs are effective against acute pain and facilitated pain state at the spinal level. Thus, the spinal combination of sildenafil with morphine may be useful in the management of the same state. Furthermore, the opioid receptor is contributable to the antinocieptive mechanism of sildenafil at the spinal level. 相似文献
59.
60.
Abortive potency of Chlamydophila abortus in pregnant mice is not directly correlated with placental and fetal colonization levels 下载免费PDF全文
Abortion, placental and fetal colonization, and levels of gamma interferon were analyzed for four Chlamydophila abortus strains presenting antigenic variations in a mouse model. Expression of virulence of these strains varied and indicated that abortion was not directly related to the number of bacteria in the placenta, and thus, other factors may have an important role in activating the abortion process. 相似文献