全文获取类型
收费全文 | 24091篇 |
免费 | 2035篇 |
国内免费 | 641篇 |
专业分类
耳鼻咽喉 | 166篇 |
儿科学 | 420篇 |
妇产科学 | 186篇 |
基础医学 | 2897篇 |
口腔科学 | 521篇 |
临床医学 | 3725篇 |
内科学 | 2581篇 |
皮肤病学 | 98篇 |
神经病学 | 3917篇 |
特种医学 | 973篇 |
外国民族医学 | 4篇 |
外科学 | 1482篇 |
综合类 | 3603篇 |
现状与发展 | 1篇 |
一般理论 | 16篇 |
预防医学 | 2323篇 |
眼科学 | 470篇 |
药学 | 2162篇 |
123篇 | |
中国医学 | 621篇 |
肿瘤学 | 478篇 |
出版年
2024年 | 109篇 |
2023年 | 979篇 |
2022年 | 1513篇 |
2021年 | 1901篇 |
2020年 | 1566篇 |
2019年 | 1223篇 |
2018年 | 922篇 |
2017年 | 850篇 |
2016年 | 760篇 |
2015年 | 757篇 |
2014年 | 1541篇 |
2013年 | 1742篇 |
2012年 | 1241篇 |
2011年 | 1419篇 |
2010年 | 972篇 |
2009年 | 1010篇 |
2008年 | 1039篇 |
2007年 | 1007篇 |
2006年 | 903篇 |
2005年 | 719篇 |
2004年 | 579篇 |
2003年 | 507篇 |
2002年 | 436篇 |
2001年 | 329篇 |
2000年 | 319篇 |
1999年 | 241篇 |
1998年 | 242篇 |
1997年 | 247篇 |
1996年 | 167篇 |
1995年 | 129篇 |
1994年 | 123篇 |
1993年 | 113篇 |
1992年 | 95篇 |
1991年 | 90篇 |
1990年 | 82篇 |
1989年 | 61篇 |
1988年 | 81篇 |
1987年 | 60篇 |
1986年 | 55篇 |
1985年 | 87篇 |
1984年 | 75篇 |
1983年 | 51篇 |
1982年 | 56篇 |
1981年 | 47篇 |
1980年 | 52篇 |
1979年 | 42篇 |
1978年 | 36篇 |
1977年 | 43篇 |
1976年 | 36篇 |
1974年 | 33篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
101.
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
102.
低角度青少年特发性脊柱侧凸女性患者的骨密度分析 总被引:1,自引:0,他引:1
目的分析低角度青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)女性患者的骨密度(BMD)和骨矿含量(BMC),探讨其与年龄、生长发育、人体测量学和侧凸角度等的相关性。方法研究对象为218例Cobb角15~40°的女性AIS患者。运用双能X线骨密度吸收仪测定非优势侧股骨颈和腰椎的BMC/BMD。探讨这两个部位的BMC/BMD与患者的年龄、生长发育、人体测量学和侧凸角度等的相关性。结果所有患者的年龄平均为(13.4±1.4)岁,Cobb角平均为(28.3±6.2)°。股骨颈BMD平均为(0.827±0.103)g/cm2,腰椎BMD平均为(0.887±0.124)g/cm2,显著低于同龄健康女性儿童;股骨颈BMC平均为(3.49±0.56)g,腰椎BMC平均为(29.78±7.37)g。患者的BMC/BMD与Cobb角无显著相关,而与体重、身高、Risser征、月经状况、BMI和年龄显著相关。逐步回归分析显示,体重和年龄是影响患者BMD的主要因素。结论低角度女性AIS患者存在全身性的骨量减低,且与Cobb角无显著相关,而与生长发育和人体测量学相关指标显著相关。这提示AIS患者的骨量减低与生长发育和低体重有关。 相似文献
103.
Research has demonstrated environmentally induced plasticity of hippocampal dentate gyrus-evoked potentials. Other research has shown a role of the NMDA receptor in dentate gyrus long-term potentiation (LTP). The authors tested the role of the NMDA receptor in one form of environmentally induced plasticity, in which transferring animals from their home cages to another environment results in significant excitatory postsynaptic potential (EPSP) enhancement and concomitant depression of the population spike. Rats were chronically implanted with stimulating electrodes in the perforant path and recording electrodes in the dentate gyrus bilaterally. Evoked potentials were recorded from freely behaving rats for four 20-minute sessions (1/wk), which took place immediately following an environmental transfer. Rats received 0.00, 0.05, 0.08, or 0.10 mg/kg MK-801 s.c. 30 minutes prior to recording sessions in either an ascending- or descending-dose series. Results showed that MK-801 produced a reduction of the EPSP enhancement, which takes place over the 20-minute session. The effects of MK-801 on spike depression varied as a function of dose series and time within a session, suggesting a long-term effect of MK-801 on spike depression. There was no detected effect of MK-801 on behavior. Results suggest a role of the NMDA receptor in this form of environmentally induced plasticity with different effects of NMDA receptor antagonism on EPSP enhancement and spike depression. 相似文献
104.
Heukrodt Carol; Powazek Morris; Brown Warren S.; Kennelly Denise; Imbus Charles; Robinson Herb; Schantz Stacy 《Journal of pediatric psychology》1988,13(2):223-236
The long-term effects of disease and treatment on electrophysiologicalmeasures of neurocognitive function were studied in childrenwho had survived acute lymphoblastic leukemia (ALL) for at least4 years and were currently in remission. We report here changesin cognitive processing time as shown by the latency of theP3 wave of the auditory event-related EEG potential (ERP). P3latency was significantly prolonged in long-term ALL surivors,as well as in patients successfully trreated for solid tumors(ST)outside the CNS who received similar chemotherapy but did notreceive prophylactic treatment to the CNS. P3 latencies werestrongly correlated with measures of school performance andIQ in these individuals. The similarity in P3 latency betweenthe ALL and ST groups suggests that the treatments used on thesepateints produce changes in electrophysiological responses thatare associated with mild, but significant, cognitive deficits. 相似文献
105.
Use of learned odor cues by newborn rats is critical for pup survival. Rat pups acquire approach responses to maternal odors through an associative conditioning mechanism. This learned behavioral response is accompanied by a modification of olfactory bulb neural response patterns to the learned odor. Both the behavioral and neural reponse changes involved and require norepinephrine release in the olfactory bulb. The source of this norepinephrine is the locus coeruleus. It is proposed that the unique response properties of the locus coeruleus during the early postnatal period in the rat may facilitate acquisition of these critical early memories. 相似文献
106.
M. V. Merrick T. M. Griffin 《European journal of nuclear medicine and molecular imaging》1994,21(6):521-524
The effect of swallowing a small quantity of water or of solid food (biscuit) on the renogram curve was observed in 177 patients. Swallowing provoked contraction of the renal pelvis in 63% of the kidneys with a pelvicalyceal system which was neither obstructed nor dilated, with expulsion of a substantial fraction of the contents within 30 s. This did not occur in obstructed or denervated kidneys, nor in patients with a high transection of the spinal cord. Evidence is adduced that this contraction is mediated reflexly. This effect may be used diagnostically to distinguish physiological dilatation from obstruction. The implications when performing and interpreting renography are discussed.
Correspondence to: M.V. Merrick 相似文献
107.
目的:评价左氧沙星与磷霉素联用对金黄色葡萄球菌的联合抗菌效应。了解左氧沙星单用及与磷霉素联用的杀菌曲线特点。方法:选取3株MSSAATCC29213、临床分离菌SA99、SARN450(实验室菌株)和1株临床分离的MRS-AB6177,采用菌落计数法对不同浓度的左氧沙星或磷霉素单用及两药联合对3株MSSA和1株MRSA进行体外杀菌实验。结果:左氧沙星的杀菌曲线表现出浓度依赖性,磷霉素的杀菌曲线表现出非浓度依赖性。两药1/4MIC浓度单用时虽然均无法抑制MSSA的生长,而两药亚抑菌浓度联合使用后即表现出协同效应和杀菌效应。两药4MIC、8MIC联合时对MRSA表现出杀菌效应。结论:亚抑菌浓度的左氧沙星与磷霉素联合对MSSA即可出现协同杀菌效应。左氧沙星联合磷霉素对MRSA也表现出显著的杀菌活性。 相似文献
108.
109.
Y. Ikemoto S. Demura S. Yamaji M. Minami M. Nakada M. Uchiyama 《Sport Sciences for Health》2007,2(2):64-70
Although explosive isometric contraction provides little work toward the outside, force-time parameters of the rising phase
of the force-time curve may be able to predict muscle power. The purpose of this study was to examine the relationship between
muscle power with work (power grip) and force-time parameters during the rising phase in explosive isometric grip. Fifteen
healthy young adult males participated in this study. Power grip was measured using loads of 20%–50% of maximal voluntary
contraction (MVC) (peak isometric force). Subjects pulled explosively on a grip bar held with the second digital joints without
the thumb. Peak power was calculated from peak velocity and load. Explosive isometric grip was measured using a hand dynamometer.
Time-series data of both tests were sampled by an analog-to-digital interface. Both tests were performed with the subjects
seated with a sagittal and horizontal position of the arm supported by an armrest. Peak power in the power grip test tended
to be larger with an increase of the load, but there was no significant difference between 40% and 50% MVC. Only the peak
power in 50% MVC significantly correlated with peak grip force (r=0.52, p<0.05). The force-time parameters related to the peak rate of the rising force phase in explosive isometric grip significantly
correlated with the peak powers (30%–50% MVC, r=|0.58−0.78|). Peak rate of the rising force phase in explosive isometric grip
may be useful for predicting muscle power with loads between 30%–50% MVC. 相似文献
110.
图片学习测验在识别老年人轻微认知功能损害中的作用 总被引:6,自引:2,他引:4
目的 分析图片学习测验在识别老年人轻微认知功能损害 (MCI)中的作用。方法 选择符合MCI诊断标准的老年人 4 8例与正常对照组 5 6名完成图片学习测验、简易智能状态检查、听觉词语学习测验及多种非记忆测验。结果 图片学习测验的 3个记忆指标 (图片短时记忆、延迟记忆和学习记忆 )在MCI与正常对照组之间有非常显著的差异。已经给出这三个图片记忆指标区分MCI与正常老年人的划界分、敏感性和特异性。结论 图片记忆操作简便、信度和效度好 ,可以作为临床医师筛选MCI的有效工具 相似文献