全文获取类型
收费全文 | 12012篇 |
免费 | 694篇 |
国内免费 | 207篇 |
专业分类
耳鼻咽喉 | 113篇 |
儿科学 | 241篇 |
妇产科学 | 125篇 |
基础医学 | 1285篇 |
口腔科学 | 146篇 |
临床医学 | 1475篇 |
内科学 | 1578篇 |
皮肤病学 | 49篇 |
神经病学 | 1286篇 |
特种医学 | 476篇 |
外国民族医学 | 4篇 |
外科学 | 1405篇 |
综合类 | 1466篇 |
现状与发展 | 1篇 |
预防医学 | 1131篇 |
眼科学 | 185篇 |
药学 | 1405篇 |
5篇 | |
中国医学 | 283篇 |
肿瘤学 | 254篇 |
出版年
2023年 | 257篇 |
2022年 | 502篇 |
2021年 | 626篇 |
2020年 | 525篇 |
2019年 | 626篇 |
2018年 | 606篇 |
2017年 | 394篇 |
2016年 | 362篇 |
2015年 | 364篇 |
2014年 | 851篇 |
2013年 | 786篇 |
2012年 | 668篇 |
2011年 | 768篇 |
2010年 | 519篇 |
2009年 | 528篇 |
2008年 | 530篇 |
2007年 | 493篇 |
2006年 | 440篇 |
2005年 | 367篇 |
2004年 | 307篇 |
2003年 | 227篇 |
2002年 | 220篇 |
2001年 | 160篇 |
2000年 | 158篇 |
1999年 | 135篇 |
1998年 | 125篇 |
1997年 | 114篇 |
1996年 | 93篇 |
1995年 | 84篇 |
1994年 | 93篇 |
1993年 | 49篇 |
1992年 | 64篇 |
1991年 | 62篇 |
1990年 | 61篇 |
1989年 | 53篇 |
1988年 | 53篇 |
1987年 | 49篇 |
1986年 | 42篇 |
1985年 | 61篇 |
1984年 | 43篇 |
1983年 | 29篇 |
1982年 | 42篇 |
1981年 | 40篇 |
1979年 | 40篇 |
1978年 | 36篇 |
1977年 | 29篇 |
1976年 | 29篇 |
1975年 | 32篇 |
1974年 | 33篇 |
1973年 | 30篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
An efficient BASIC program was established on Apple-Ⅱmicrocomputer with the CHESTAC-35F pulmonary function testing system tocalculate the time-constant histogram from the spirogram.By a set of analogousstudies,we confirmed that the recovered time-constant histogram was within onecompartment of the assumed one and that the root of mean square values of theresiduals between the experimental and model volume-time curves was 0.02.Infour healthy adult subjects,the mean value of time-constant histograms(TCx)hadthe variation coefficient 6.6%.The results show that our method is reliable andreproducible,and it can be used for clinical investigation. 相似文献
42.
To increase preschoolers' science and mathematics learning experiences both within and outside the classroom, we developed age-appropriate materials containing general questions and instructions that teachers and parents could use when interacting with their students and children. The questions and instructions were related to a specific science or mathematics skill (e.g., classifying), but were general enough so that they could be applied to a variety of situations. Observations of three classrooms and interviews with the classroom teachers and aides, and the parents of the children in the classrooms suggested that use of these materials was beneficial to the children, teachers, and parents, and resulted in increasing the amount of science and mathematics activities and discussions in two of the classrooms as well as outside the classrooms. 相似文献
43.
目的提出对学习策略和教学方式的改进建议。方法测试口腔医学生的场依存/独立认知风格,并用统计学方法分析其与口腔正畸学学习成绩的关系。结果①场独立认知风格是口腔医学专业学生认知风格的主体;②不同性别口腔医学专业学生的场依存/独立认知风格无显著性差异;③学生场依存/独立认知风格与口腔正畸学理论考试成绩有负相关倾向,与口腔正畸学实习操作成绩有正相关倾向。结论学习策略和教学方式因受认知风格的影响而制约学生学习的效果。 相似文献
44.
本文研究了~(60)Co-γ射线照射后HeLa细胞的存活曲线,比较了两种数学模式拟合的结果.拟合优度以对误差加权的残差平方和(Q)作为统计指标进行评价.结果表明模式的拟合度较模式为优. 相似文献
45.
C. Vyvyan Howard Luis M. Cruz-Orive Hiroshi Yaegashi 《Acta neurologica Scandinavica》1992,85(S137):14-19
The recently developed method of total vertical projections is illustrated to estimate the total dendritic length of a human Substantia Nigra neuron. Next, the length of the different orders of dendritic branches, and the mean segment length for each order - commonly regarded as important parameters in neuron physiology - are also estimated. Finally, it is shown how to estimate the mean dendritic length in a population of neurons from vertical slices of arbitrary and unknown thickness. Being unbiased and highly efficient, the proposed methods offer interesting alternatives to current procedures used for the metric analysis of neuron arborizations. 相似文献
46.
采用Gompertz曲线对莒县1986~1990年胃瘤年龄别死亡率进行了拟合检验,并与直线、指数曲线、二次抛物线进行了比较,以Gompertz曲线拟合比较理想。描绘了胃癌死亡率年龄分布的理论轨迹,为胃癌死亡预测提供了一种简便科学的方法。 相似文献
47.
BALB/c mice were bilaterally implanted with bipolar electrodes either in anterodorsal (ADH) or posteroventral hippocampus (PVH) in order to compare the effects of postsession electrical stimulation on memory processes. For each experiment, 30 s after the end of the first session, the animals were stimulated during 80 s. For both hippocampal regions, the stimulation intensity was half of the afterdischarge threshold value. Control groups were naive, ADH and PVH implanted non-stimulated animals. Different appetitive and aversive tasks were used. Subseizure stimulation never created a deficit. Depending on the region of the hippocampus stimulated and on the learning task, a retention enhancement was eventually observed. These data are in agreement with the involvement of hippocampus in initial stages of memory consolidation. Further, the subseizure stimulation permitted a functional dissociation between the two hippocampal regions. Both regions seemed involved in the integration of information, but the anterodorsal part would be rather related to behavioral inhibition, while the posteroventral part would have the capacity to induce an arousal state allowing behavioral flexibility. 相似文献
48.
Liposomes as drug carriers in cancer chemotherapy have attracted considerable interest. To enhance the therapeutic effect of Adriamycin entrapped in liposomes (Lip-ADM) on human solid tumors, we investigated the therapeutic effects of Lip-ADM in combination with recombinant human tumor necrosis factor-alpha (rTNF-alpha), which is known to have specific effects on tumor vasculature. rTNF-alpha or saline solution was injected intravenously into nude mice bearing a human colon cancer strain, HC-1, at 1 hour before intravenous administration of Lip-ADM. The significant therapeutic effect of Lip-ADM in combination with rTNF-alpha was demonstrated by the evaluation with tumor growth curve and the actual tumor weights, in comparison with groups of mice treated with saline solution, rTNF-alpha alone, or with a Lip-ADM after saline. Levels of Adriamycin in tumor tissue in the Lip-ADM in combination with rTNF-alpha-treated group were higher than those in Lip-ADM with saline solution-treated group. 相似文献
49.
50.
The present study was designed to investigate the effects of combined treatment with a serotonin (5-HT)1A receptor agonist, 8-hydroxy-2-(dipropylamino)-tetralin (8-OH-DPAT), and a muscarinic acetylcholine receptor antagonist, scopolamine, on water maze (WM) navigation. Treatment with either 8-OH-DPAT or scopolamine before daily behavioral training disrupted spatial navigation at medium doses and cue navigation at high doses. Pretraining treatment with a combination of subthreshold doses of 8-OH-DPAT and scopolamine impaired WM spatial and cue navigation, but did not impair the WM performance if the drugs were injected post-training. In trained rats, combined injections of subthreshold doses of 8-OH-DPAT and scopolamine given pretraining did not impair the rats' ability to find the platform in a familiar or in a novel position. The combination of 8-OH-DPAT and scopolamine also disrupted WM navigation in rats with central 5-HT depletion. A combination of a peripheral muscarinic acetylcholine receptor antagonist and 8-OH-DPAT had no effect on WM navigation. These data suggest that combined treatment with drugs blocking muscarinic acetylcholine receptors and activating 5-HT1A receptors greatly impairs WM learning/performance, but does not impair spatial memory per se. 相似文献