全文获取类型
收费全文 | 1351篇 |
免费 | 83篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 166篇 |
儿科学 | 30篇 |
妇产科学 | 7篇 |
基础医学 | 207篇 |
口腔科学 | 34篇 |
临床医学 | 199篇 |
内科学 | 203篇 |
皮肤病学 | 5篇 |
神经病学 | 167篇 |
特种医学 | 39篇 |
外科学 | 92篇 |
综合类 | 114篇 |
预防医学 | 126篇 |
眼科学 | 2篇 |
药学 | 35篇 |
2篇 | |
中国医学 | 25篇 |
肿瘤学 | 10篇 |
出版年
2024年 | 4篇 |
2023年 | 12篇 |
2022年 | 59篇 |
2021年 | 78篇 |
2020年 | 46篇 |
2019年 | 35篇 |
2018年 | 45篇 |
2017年 | 41篇 |
2016年 | 37篇 |
2015年 | 66篇 |
2014年 | 61篇 |
2013年 | 109篇 |
2012年 | 61篇 |
2011年 | 54篇 |
2010年 | 61篇 |
2009年 | 65篇 |
2008年 | 49篇 |
2007年 | 51篇 |
2006年 | 57篇 |
2005年 | 38篇 |
2004年 | 49篇 |
2003年 | 33篇 |
2002年 | 27篇 |
2001年 | 25篇 |
2000年 | 35篇 |
1999年 | 18篇 |
1998年 | 19篇 |
1997年 | 29篇 |
1996年 | 20篇 |
1995年 | 21篇 |
1994年 | 10篇 |
1993年 | 10篇 |
1992年 | 11篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 15篇 |
1988年 | 14篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 16篇 |
1984年 | 11篇 |
1983年 | 13篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有1463条查询结果,搜索用时 31 毫秒
1.
2.
Keiichiro Kume Masahiro Yamasaki Ichiro Yoshikawa Makoto Otsuki 《Digestive endoscopy》2006,18(3):218-220
Background: Although bleeding is an unavoidable complication of endoscopic submucosal dissection (ESD), endoscopic hemostasis using an insulation‐tipped electrosurgical knife (IT) knife is impossible because an insulator is mounted at the tip of the knife. We have developed a new type of hood which could perform both coagulation and irrigation simultaneously. Methods: Our new device was fabricated by drilling a side hole in the cap portion of a conventional transparent hood followed by attaching a machined papillotomy knife to the exterior surface of the hole. Results: Our new hood was useful for hemorrhage during ESD using IT knife. Conclusions: With this method, endoscopic hemostasis using IT knife is easy, as hemostatic procedure can be performed under irrigation and coagulation using conventional endoscopy. 相似文献
3.
Yasushi Sano Hirohisa Machida Kuang‐I. Fu Hiroaki Ito Takahiro Fujii 《Digestive endoscopy》2004,16(Z1):S93-S96
The goal of endoscopic mucosal resection (EMR) is to allow the endoscopist to obtain tissue or resect lesions not previously amenable to standard biopsy or excisional techniques and to remove malignant lesions without open surgery. In this article, we describe the results of conventional EMR and EMR using an insulation‐tipped (IT) electrosurgical knife (submucosal dissection method) for large colorectal mucosal neoplasms and discuss the problems and future prospects of these procedures. At present, conventional EMR is much more feasible than EMR using IT‐knife from the perspectives of time, money, complication, and organ preservation. However, larger lesions tend to be resected in a piecemeal fashion; and it is difficult to confirm whether EMR has been complete. For accurate histopathological assessment of the resected specimen en bloc EMR is desirable although further experience is needed to establish its safety and efficacy. Further improvements of in EMR with special knife techniques are required to simply and safely remove large colorectal neoplasms. 相似文献
4.
Pleural mesotheliomas and asbestos exposure in the pulp and paper industries: a new risk group identified by linkage of official registers 总被引:4,自引:0,他引:4
Bengt Jrvholm Hans Malker Birgitta Malker Jan Ericsson Gerd Sllsten 《American journal of industrial medicine》1988,13(5):561-567
Analysis of data obtained by linking the 1960 Swedish Census and the Swedish Cancer Registry has demonstrated an increased risk of pleural mesothelioma among pulp and paper workers. The present study was undertaken with the aim of revealing possible environmental risk factors. The work histories of the 25 cases identified earlier were reviewed. "Certain" or "probable" exposure to asbestos was found among 70% of these workers. The study illustrates how linkage of official registers can be used to identify new risk environments and encourage the establishment of preventive measures. 相似文献
5.
Males ofDrosophila littoralis vibrate their wings during courtship to deliver a love song. This consists of 25- to 50-ms-long pulses with a basic frequency of about 250–400 Hz, separated by 250- to 500-ms pauses. When recording the sounds of flies from several localities in Europe, we found that males of one strain from northern Finland displayed courtship sounds with an unusally low wing beat frequency (below 250 Hz). In a genetic analysis utilizing marker stocks, the anomalous frequency was found to be caused by genes on all major autosomes, the strongest factors being on the second chromosome. Interaction between genes on chromosome 2 and on the fused chromosome 3–4 was nonadditive. In low-frequency sounds, the number of cycles in the pulse (CN) was decreased, so that the length of the sound pulse (PL) remained more or less unchanged. We suggest that the genetically and physiologically most thoroughly controlled trait in the sound ofDrosophila littoralis is the length of the pulse. 相似文献
6.
本文对肠道运动进行分析,从结构上研究肠鸣音的产生机理和肠鸣音的时域、频域特点,从而得到其物理模型,并用等效电路来模拟肠鸣音的产生,为研究肠鸣音的数学模型,以及临床医学研究提供了方便。 相似文献
7.
8.
9.
10.
Popov AV Sitnik NA Savvateeva-Popova EV Wolf R Heisenberg M 《Neuroscience and behavioral physiology》2003,33(1):53-65
The question of the roles of the two main parts of the insect brain, the mushroom bodies and the central complex, in controlling motor coordination and triggering a variety of behavioral programs, including sound production, remains controversial. With the aim of improving our understanding of this question, we studied the parameters of songs used by five-day-old males during courtship for fertilized wild-type females (Canton-S, C-S) over 5-min periods at 25°C; males were of two wild-type Drosophila Melanogaster lines (Berlin and C-S). Berlin males lacking mushroom bodies because of treatment with hydroxyurea during development (chemical removal of the mushroom bodies) were used, along with two mutants with defects in the mushroom bodies (mbm
1 and mud
1), two mutants with defects in the central complex (ccb
KS127 and cex
KS181), and mutant cxb
N71 with defects in both the mushroom bodies and the central complex. The experiments reported here showed that courtship songs in males lacking mushroom bodies were virtually identical to those of wild-type males. The main parameters of pulsatile song in mutants mbm
1 and mud
1 (interpulse interval and train duration) were insignificantly different from those of the songs of wild-type flies, though the stability of the pulse oscillator was the same. Flies of these lines were no different from wild-type flies in terms of courtship success (percentage of copulating pairs in 10-min tests). Conversely, the songs of mutants with defects in the central complex differed from those of wild-type males. Firstly, there was degradation of the stability of the pulse oscillator and interpulse intervals were very variable. In addition, pulses were often significantly longer and appeared multicyclic, as in the well-known cacophony mutant, while the mean train duration was significantly shorter. Males of the line cex
KS181 usually courted very intensely, though abnormal sounds were generally emitted. Mutants cex
KS181 and ccb
KS127 were significantly less successful in courtship than wild-type flies. These data show that the central complex appears to play a very important role in controlling song, while the mushroom bodies are not related to this function. 相似文献