全文获取类型
收费全文 | 52070篇 |
免费 | 5331篇 |
国内免费 | 1283篇 |
专业分类
耳鼻咽喉 | 349篇 |
儿科学 | 987篇 |
妇产科学 | 654篇 |
基础医学 | 4289篇 |
口腔科学 | 1685篇 |
临床医学 | 5294篇 |
内科学 | 6802篇 |
皮肤病学 | 611篇 |
神经病学 | 4074篇 |
特种医学 | 1923篇 |
外国民族医学 | 8篇 |
外科学 | 3903篇 |
综合类 | 5996篇 |
现状与发展 | 5篇 |
一般理论 | 2篇 |
预防医学 | 8357篇 |
眼科学 | 664篇 |
药学 | 4399篇 |
30篇 | |
中国医学 | 5092篇 |
肿瘤学 | 3560篇 |
出版年
2024年 | 199篇 |
2023年 | 1133篇 |
2022年 | 1693篇 |
2021年 | 2144篇 |
2020年 | 2150篇 |
2019年 | 2122篇 |
2018年 | 2059篇 |
2017年 | 1995篇 |
2016年 | 1887篇 |
2015年 | 1737篇 |
2014年 | 3682篇 |
2013年 | 3745篇 |
2012年 | 3144篇 |
2011年 | 3328篇 |
2010年 | 2550篇 |
2009年 | 2417篇 |
2008年 | 2697篇 |
2007年 | 2747篇 |
2006年 | 2410篇 |
2005年 | 2016篇 |
2004年 | 1681篇 |
2003年 | 1587篇 |
2002年 | 1243篇 |
2001年 | 1154篇 |
2000年 | 916篇 |
1999年 | 744篇 |
1998年 | 565篇 |
1997年 | 639篇 |
1996年 | 487篇 |
1995年 | 495篇 |
1994年 | 433篇 |
1993年 | 349篇 |
1992年 | 335篇 |
1991年 | 320篇 |
1990年 | 273篇 |
1989年 | 230篇 |
1988年 | 227篇 |
1987年 | 175篇 |
1986年 | 150篇 |
1985年 | 145篇 |
1984年 | 142篇 |
1983年 | 97篇 |
1982年 | 87篇 |
1981年 | 85篇 |
1980年 | 72篇 |
1979年 | 46篇 |
1978年 | 36篇 |
1977年 | 34篇 |
1976年 | 22篇 |
1975年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
151.
目的探讨稳定、可靠建立神经干细胞体外增殖的方法,并对增殖培养的细胞进行鉴定。方法获取胚胎大鼠的脑组织,通过加入神经生长因子和采用保留细胞联系技术操作,使脑组织中的神经干细胞在体外克隆增殖并稳定传代。以免疫荧光方法对增殖克隆的神经干细胞球进行鉴定。结果神经干细胞不断增殖形成神经干细胞球且神经干细胞能快速稳定传代增殖。培养的细胞为神经干细胞特异性巢蛋白(nestin)染色阳性细胞。结论在神经生长因子的作用下,利用保留细胞联系技术操作,神经干细胞可以在体外快速、稳定克隆增殖并传代。 相似文献
152.
肾宁口服液对兔膜性肾病模型肾保护作用的实验研究 总被引:1,自引:0,他引:1
目的观察肾宁口服液治疗膜性肾病的实验研究.方法用阳离子牛血清白蛋白(C-BSA)制备家免膜性肾病模型,设立正常对照组、中药治疗组、激素治疗组和模型组.每周测定一次24h尿蛋白,实验结束时测定血浆白蛋白、血脂和肾功能等生化指标.结果肾宁口服液中药治疗组的24h尿蛋白、血脂和肾功能等生化指标较模型组明显改善(P<0.01或P<0.05),而激素治疗组与模型组比较无明显差异(P>0.05).结论肾宁口服液能降低尿蛋白,提高血浆白蛋白,改善肾功能,对膜性肾病有显著疗效. 相似文献
153.
平喘合剂治疗小儿哮喘发作期的临床研究 总被引:2,自引:0,他引:2
马婷 《山东中医药大学学报》2004,28(2):121-125
认为哮喘是外因作用于内因的结果 ,痰瘀伏肺为其宿根 ,外邪引触伏痰、痰瘀胶结、阻塞气道、痰阻气逆为其病机 ,寒热夹杂为其病性。具有宣肺化痰、降气平喘、清热活血功效的中药平喘合剂可明显改善哮喘发作期患儿的肺通气功能 ,明显降低患儿血浆中sICAM 1、IgE水平 ,与对照组比较有显著性差异 (P <0 .0 1,P <0 .0 5 ) ,推测其作用机制可能与减轻气道阻塞、调节免疫反应及抑制气道炎症等多个环节有关 相似文献
154.
活动性结核标志物'H-多肽的实验与临床研究 总被引:2,自引:0,他引:2
本题研究是经免疫学途径直接检测人体感染结核菌的情况,为现代结核病的实验诊断、临床监测、流行病调查提供了一个全新的检验指标。作者首先发现了一种仅存在于活动性结核病患者体液中的蛋白成份—活动性结核标志物(ActiveTuberculosisMark—ATM)1H—多肽;并为之创立了独特的检测方法,经四年多临床19460例样本调查中确定了ATM的临床价值。将ATM检测与OT皮试、酶联免疫ELISA、DNA探针、PCR基因扩增技术及典型病例组患者行X线计算机断层摄影(CT)、磁共振像(MRI)等多组对比试验中,实验与临床研究资料分析证明:ATM检测的总敏感度为86.06%、特异度96.24%、准确度93.45%、诊断效率为82.82%、批内CV1.2%、批间CV2.0%、P<0.05。经NMR光谱分析结构含有CCH2官能团。 相似文献
155.
156.
申屠军 《安徽卫生职业技术学院学报》2004,3(4):84-85
在建设学习型社会和新课改的新形势下,高中生物教师应确立三种意识:"学习意识、信息意识、科研意识",不断提高自身素质,使自己成为一名学者型、研究型的现代生物教师. 相似文献
157.
Quantitative magnetization transfer imaging (qMTI) methods are able to estimate fundamental sample parameters, such as the relative size of the solid-like macromolecular proton pool and the spin exchange rate between this pool and the directly measured free water protons. One such method is selective inversion recovery (SIR), in which the free water protons are selectively inverted and the signal is fit to a biexponential function of the inversion time (TI). SIR uses only low-power pulses and requires no separate RF (B1) or static field (B0) field maps, and the analysis is largely independent of the macromolecular pool lineshape. These are all advantages over steady-state off-resonance saturation qMTI methods. However, up to now, SIR has been implemented only with repetition times TR>T1. This paper describes a modification of SIR with smaller TR values and a greater signal-to-noise ratio (SNR) efficiency. 相似文献
158.
目的:为了优化风痛灵颗粒的制各工艺。方法:采用正交试验以阿魏酸、多糖等为指标。结果:得出最佳的浸提工艺参数,同时考察了最佳的喷雾干燥及制粒条件。结论:本方法是风痛灵颗粒的最佳的制备方法。 相似文献
159.
Jan Stulik Tobias Rainer Pitzen Jan Chrobok Sabine Ruffing Jörg Drumm Laurentius Sova Ravel Kucera Tomas Vyskocil Wolf Ingo Steudel 《European spine journal》2007,16(10):1689-1694
Anterior cervical plate fixation is an approved surgical technique for cervical spine stabilization in the presence of anterior
cervical instability. Rigid plate design with screws rigidly locked to the plate is widely used and is thought to provide
a better fixation for the treated spinal segment than a dynamic design in which the screws may slide when the graft is settling.
Recent biomechanical studies showed that dynamic anterior plates provide a better graft loading possibly leading to accelerated
spinal fusion with a lower incidence of implant complications. This, however, was investigated in vitro and does not necessarily
mean to be the case in vivo, as well. Thus, the two major aspects of this study were to compare the speed of bone fusion and
the rate of implant complications using either rigid- or dynamic plates. The study design is prospective, randomized, controlled,
and multi-centric, having been approved by respective ethic committees of all participating sites. One hundred and thirty-two
patients were included in this study and randomly assigned to one of the two groups, both undergoing routine level-1- or level-2
anterior cervical discectomy with autograft fusion receiving either a dynamic plate with screws being locked in ap - position
(ABC, Aesculap, Germany), or a rigid plate (CSLP, Synthes, Switzerland). Segmental mobility and implant complications were
compared after 3- and 6 months, respectively. All measurements were performed by an independent radiologist. Mobility results
after 6 months were available for 77 patients (43 ABC/34 CSLP). Mean segmental mobility for the ABC group was 1.7 mm at the
time of discharge, 1.4 mm after 3 months, and 0.8 mm after 6 months. For the CSLP- group the measurements were 1.0, 1.8, and
1.7 mm, respectively. The differences of mean segmental mobility were statistically significant between both groups after
6 months (P = 0.02). Four patients of the CSLP-group demonstrated surgical hardware complications, whereas no implant complications were
observed within the ABC-group (P = 0.0375). Dynamic plate designs provided a faster fusion of the cervical spine compared with rigid plate designs after prior
spinal surgery. Moreover, the rate of implant complications was lower within the group of patients receiving a dynamic plate.
These interim results refer to a follow-up period of 6 months after prior spinal surgery. Further investigations will be performed
2 years postoperatively. 相似文献
160.
Disc replacement using Pro-Disc C versus fusion: a prospective randomised and controlled radiographic and clinical study 总被引:4,自引:0,他引:4
A. Nabhan F. Ahlhelm T. Pitzen W. I. Steudel J. Jung K. Shariat O. Steimer F. Bachelier D. Pape 《European spine journal》2007,16(3):423-430
Anterior cervical discectomy and fusion (ACDF) may be considered to be the gold standard for treatment of symptomatic degenerative
disc disease within the cervical spine. However, fusion of the segment may result in progressive degeneration of the adjacent
segments. Therefore, dynamic stabilization procedures have been introduced. Among these, artificial disc replacement by disc
prosthesis seems to be promising. However, to be so, segmental motion must be preserved. This, again, is very difficult to
judge and has not yet been proven. The aim of the current study was to first analyse the segmental motion following artificial
disc replacement using a disc prosthesis. A second aim was to compare both segmental motion as well as clinical result to
the current gold standard (ACDF). This is a prospective controlled study. Twenty-five patients with cervical disc herniation
were enrolled and assigned to either study group (receiving a disc prosthesis) or control group (receiving ACDF, using a cage
with bone graft and an anterior plate.) Radiostereometric analysis was used to quantify intervertebral motion immediately
as well as 3, 6, 12 and 24 weeks postoperatively. Further, clinical results were judged using visual analogue scale and neuro-examination.
Cervical spine segmental motion decreased over time in the presence of disc prosthesis or ACDF. However, the loss of segmental
motion is significantly higher in the ACDF group, when looked at 3, 6, 12 and 24 weeks after surgery. We observed significant
pain reduction in neck and arm postoperatively, without significant difference between both groups (P > 0.05). Cervical spine disc prosthesis preserves cervical spine segmental motion within the first 6 months after surgery.
The clinical results are the same when compared to the early results following ACDF. 相似文献