全文获取类型
收费全文 | 31462篇 |
免费 | 1578篇 |
国内免费 | 741篇 |
专业分类
耳鼻咽喉 | 326篇 |
儿科学 | 673篇 |
妇产科学 | 1518篇 |
基础医学 | 8181篇 |
口腔科学 | 706篇 |
临床医学 | 1961篇 |
内科学 | 3061篇 |
皮肤病学 | 519篇 |
神经病学 | 1794篇 |
特种医学 | 609篇 |
外科学 | 1689篇 |
综合类 | 3293篇 |
预防医学 | 3611篇 |
眼科学 | 312篇 |
药学 | 3354篇 |
4篇 | |
中国医学 | 333篇 |
肿瘤学 | 1837篇 |
出版年
2023年 | 270篇 |
2022年 | 528篇 |
2021年 | 734篇 |
2020年 | 737篇 |
2019年 | 711篇 |
2018年 | 746篇 |
2017年 | 849篇 |
2016年 | 812篇 |
2015年 | 938篇 |
2014年 | 1741篇 |
2013年 | 1818篇 |
2012年 | 1604篇 |
2011年 | 1944篇 |
2010年 | 1512篇 |
2009年 | 1553篇 |
2008年 | 1614篇 |
2007年 | 1488篇 |
2006年 | 1340篇 |
2005年 | 1122篇 |
2004年 | 994篇 |
2003年 | 932篇 |
2002年 | 699篇 |
2001年 | 673篇 |
2000年 | 653篇 |
1999年 | 583篇 |
1998年 | 603篇 |
1997年 | 548篇 |
1996年 | 582篇 |
1995年 | 594篇 |
1994年 | 564篇 |
1993年 | 474篇 |
1992年 | 447篇 |
1991年 | 374篇 |
1990年 | 338篇 |
1989年 | 302篇 |
1988年 | 282篇 |
1987年 | 229篇 |
1986年 | 181篇 |
1985年 | 283篇 |
1984年 | 268篇 |
1983年 | 158篇 |
1982年 | 151篇 |
1981年 | 142篇 |
1980年 | 126篇 |
1979年 | 112篇 |
1978年 | 88篇 |
1977年 | 70篇 |
1976年 | 59篇 |
1974年 | 41篇 |
1973年 | 37篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
41.
42.
凋亡相关基因突变与人类疾病 总被引:4,自引:2,他引:2
细胞凋亡 (又称细胞程序性死亡 )过程由多种不同基因产物的协同作用来完成。其中某些凋亡基因的突变 ,已被认定为人类疾病的病因或相关因素。作者综述了当前对凋亡基因突变所致人类疾病的认识 ,以及将凋亡的基础研究成果应用到临床疾病诊治的情况 相似文献
43.
We correlated MRI features with histopathological findings in an HIV-positive patient with vacuolar myelopathy. On MRI symmetrical
nonenhancing high-signal areas in the posterior columns on T2-weighted images result from extensive vacuolation visible on
histological sections.
Received: 18 November 1997 Accepted: 23 March 1997 相似文献
44.
人乳头瘤病毒感染的多灶性的临床分析 总被引:10,自引:0,他引:10
对176例外阴尖锐湿疣患者的子宫颈进行检测,以诊断是否同时伴有人乳头状瘤病毒(HPV)感染。结果:肉眼观察诊断宫颈HPV感染23例(13%),阴道镜诊断146例(83%),宫颈活检病理诊断112例(64%),其中合并宫颈上皮内瘤变(CIN)1 ̄2级32例(18%)。结果提示:(1)外阴尖锐湿疣患者子宫颈伴有HPV感染和/或亚临床感染相当常见。(2)借助阴道镜取宫颈活检是诊断宫颈HPV感染的常用方法 相似文献
45.
E. M. Robertson R. C. Miall 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1997,117(1):148-152
The human arm is kinematically redundant, which may allow flexibility in the execution of reaching movements. We have compared
reaching movements with and without kinematic redundancy to unpredictable double-step targets. Subjects sat in front of a
digitising tablet and were able to view an arc of four targets reflected in the mirror as virtual images in the plane of the
tablet. They were instructed to move, from a central starting point, in as straight a line as possible to a target. In one-third
of trials, the target light switched to one of its neighbours during the movement. Subjects made 60 movements using shoulder,
elbow and wrist and then another 60 movements in which only shoulder and elbow movement were allowed. By restraining the wrist,
the limb was made non-redundant. The path length was calculated for each movement. In single-step trials, there was no significant
difference between path lengths performed with and without wrist restraint. As expected there was a significant increase in
path length during double-step trials. Moreover this increase was significantly greater when the wrist was restrained. The
variability across both single- and double-step movements was significantly less while the wrist was restrained. Importantly
the performance time of the movements did not alter significantly for single-step, double-step or restrained movements. These
results suggest that the nervous system exploits the intrinsic redundancy of the limb when controlling voluntary movements
and is therefore more effective at reprogramming movements to double-step targets.
Received: 24 March 1997 / Accepted: 7 July 1997 相似文献
46.
大气中不同粒径颗粒物诱导人羊膜FL细胞UDS的研究 总被引:3,自引:0,他引:3
本研究以诱导人羊膜细胞UDS为指标,对太原市大气不同粒径的颗粒物提取液进行了致突变性检验,结果表明,不同粒径颗粒物的提取液均可产生一定的遗传毒性,尤以3.3μm以下的颗粒物的遗传毒性较强。 相似文献
47.
In human Y-79 retinoblastoma cells corticotropin-releasing hormone (CRH) produces a marked and rapid increase of adenylate cyclase activity. The concentration of the peptide producing half-maximal stimulation is 60 nM. The effect of CRH is significantly antagonized by the specific CRH receptor antagonist alpha-helical CHR 9-41 and is mimicked by sauvagine and urotensin I, two peptides displaying sequence homology with CRH. These results demonstrate the presence of functional CRH receptors in human Y-79 retinoblastoma cells and suggest that this cell line may be a suitable model in which to study the action of CRH on human retinal cell function. 相似文献
48.
Evidence for the presence of substance P-like immunoreactivity in the human cerebellum 总被引:1,自引:0,他引:1
M. Del Fiacco M. T. Perra M. Quartu M. D. Rosa G. Zucca M. C. Levanti 《Brain research》1988,446(1):173-177
Preliminary results on the localization of substance P-like immunoreactivity in the human cerebellum are presented. Cerebella from newborn and adult subjects were examined. While only sporadic positive fibres were detected in the adult tissue, the immunoreactive material appeared more abundant in the cerebella from newborn subjects. Varicose and non-varicose fibres and dot-like nerve terminals were present with different density in various regions. The paucity of immunoreactive perikarya suggests that most of the cerebellar substance P-like immunoreactive material has an extrinsic origin. 相似文献
49.
Peter Van Gelder Sergey Lebedev Wai Hon Tsui 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1997,116(2):201-215
Smooth pursuit typically includes corrective catch-up saccades, but may also include such intrusive saccades away from the
target as anticipatory or large overshooting saccades. We sought to differentiate catch-up from anticipatory and overshooting
saccades by their peak velocities, to see whether the higher velocities of visually rather than nonvisually guided saccades
in saccadic tasks may be found also in saccades in pursuit. In experiment 1, 12 subjects showed catch-up, anticipatory, and
overshooting saccades to comprise 70.4% of all saccades in pursuit of periodic, 30°/s constant-velocity targets. Catch-up
saccades were faster than the others. Saccadic tasks were run as well, on 19 subjects, including the 12 whose pursuit data
were analyzed, with target-onset, target-remaining (saccade to the remaining target when the other three extinguish), and
antisaccade tasks. For 17 of the 19 subjects, antisaccade velocities were lower than for either target-onset or target-remaining
tasks. Velocities for the target-remaining task were near those for target onset, indicating that target presence, not its
onset, defines visually guided saccades. Error and reaction-time data suggest greater cognitive difficulty for target remaining
than for target onset, so that the cognitive difficulty of typical nonvisually guided saccade tasks is not sufficient to produce
their lowered velocity. To produce reliably, in each subject, catch-up and anticipatory saccades with comparable amplitude
distributions, nine new subjects were asked in experiment 2 to make intentional catch-up and anticipatory saccades in pursuit,
and were presented with embedded target jumps to elicit catch-up saccades, all with periodic target trajectories of 15°/s
and 30°/s. Velocities of intentional anticipatory saccades were lower than velocities of intentional catch-up saccades, while
velocities of intentional and embedded catch-up saccades were similar. Target-onset and remembered-target saccadic tasks were
run, showing the expected higher velocity for the target-onset task in each subject. Both experiments demonstrate higher peak
velocities for catch-up saccades than for anticipatory saccades, suggesting that cortical structures preferentially involved
in nonvisually guided saccades may initiate the anticipatory and overshooting saccades in pursuit.
Received: 1 December 1995 / Accepted: 25 February 1997 相似文献
50.