全文获取类型
收费全文 | 25388篇 |
免费 | 2118篇 |
国内免费 | 1263篇 |
专业分类
耳鼻咽喉 | 239篇 |
儿科学 | 142篇 |
妇产科学 | 473篇 |
基础医学 | 901篇 |
口腔科学 | 176篇 |
临床医学 | 2166篇 |
内科学 | 1587篇 |
皮肤病学 | 240篇 |
神经病学 | 542篇 |
特种医学 | 565篇 |
外国民族医学 | 6篇 |
外科学 | 1657篇 |
综合类 | 5084篇 |
现状与发展 | 2篇 |
预防医学 | 995篇 |
眼科学 | 810篇 |
药学 | 8097篇 |
30篇 | |
中国医学 | 4435篇 |
肿瘤学 | 622篇 |
出版年
2024年 | 81篇 |
2023年 | 273篇 |
2022年 | 529篇 |
2021年 | 788篇 |
2020年 | 730篇 |
2019年 | 617篇 |
2018年 | 821篇 |
2017年 | 901篇 |
2016年 | 1040篇 |
2015年 | 934篇 |
2014年 | 2098篇 |
2013年 | 1940篇 |
2012年 | 2199篇 |
2011年 | 2316篇 |
2010年 | 1735篇 |
2009年 | 1418篇 |
2008年 | 1310篇 |
2007年 | 1369篇 |
2006年 | 1247篇 |
2005年 | 1100篇 |
2004年 | 808篇 |
2003年 | 722篇 |
2002年 | 623篇 |
2001年 | 533篇 |
2000年 | 387篇 |
1999年 | 334篇 |
1998年 | 258篇 |
1997年 | 216篇 |
1996年 | 189篇 |
1995年 | 168篇 |
1994年 | 152篇 |
1993年 | 109篇 |
1992年 | 80篇 |
1991年 | 109篇 |
1990年 | 86篇 |
1989年 | 62篇 |
1988年 | 63篇 |
1987年 | 45篇 |
1986年 | 31篇 |
1985年 | 60篇 |
1984年 | 54篇 |
1983年 | 36篇 |
1982年 | 38篇 |
1981年 | 32篇 |
1980年 | 17篇 |
1979年 | 27篇 |
1978年 | 23篇 |
1977年 | 17篇 |
1976年 | 11篇 |
1975年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
注射用克林霉素磷酸酯的稳定性研究 总被引:2,自引:0,他引:2
目的:对影响注射用克林霉素磷酸酯稳定性的各种因素进行考察,方法:采用高效液相色谱法测定注射用克林霉素磷酸酯的稳定性。结果:温度对本制剂稳定性有影响,对光稳定性较好。结论:本制剂应于凉暗干燥处贮存。 相似文献
42.
43.
为了观察经皮穿刺注射无水乙醇对肺组织的局部作用和全身影响 ,为经皮穿刺注射无水乙醇 (PEI)治疗肺癌的安全性和可行性提供依据 ,我们进行了家兔肺内PEI的初步实验研究。结果显示 :PEI后的第 1天至第 3天 ,注射局部的肺组织发生凝固性坏死 ,周围肺水肿、充血 ,伴大量嗜中性白细胞浸润。 1~ 2周后 ,肺局灶性上皮细胞肉芽组织增生 ,最后纤维化。PEI早期既无大面积肺组织坏死 ,亦无明显的全身副作用。本研究结果提示 ,肺内PEI是安全可行的 相似文献
44.
包玉莲 《菏泽医学专科学校学报》2000,12(2):84-85
目的静脉输液拔针后,按压血管多长时间较为合适,目前尚无定论。旨在探讨按压血管的最佳时间,以便最大限度地减少皮下瘀血,减轻病人痛苦,保护静脉血管。方法对200例静脉输液病人拔针后不同按压血管时间的效果进行了观察,并根据统计处理结果进行分析、比较。结果拔针后4min左右较为合适,能够有效地防止瘀血,时间过长,多数病人难以坚持;过短则皮下瘀血率高。结论这种做法,克服了过去静脉输液拔针后,按压血管时间随意性较大的缺陷,应大力推广。 相似文献
45.
Andreas Obruca Karl Mock Wilfried Feichtinger Gerhard Lunglmayr 《Journal of assisted reproduction and genetics》1995,12(9):627-631
Purpose
Intracytoplasmic injection (ICSI) with testicular sperm was performed in 16 couples. All men had ductal obstruction and failed previous attempts of epididymal sperm microaspiration.Methods
Testis tissue was obtained by excisional biopsies and incubated in HEPES buffered EBSS medium over 24 h at 37C. Motile sperm (Grade 1 to 2) were recovered in 13 patients and fertilized a total of 62 oozytes. Four pregnancies were achieved.Results
One healthy boy and two girls (twin pregnancy) were born.Conclusions
The ongoing pregnancies revealed no fetal abnormalities on ultrasound scanning.Presented at the IXth World Congress on In Vitro Fertilization and Alternate Assisted Reproduction, April 3–7, 1995, Vienna, Austria. 相似文献
46.
Vendrell JM García F Veiga A Calderón G Egozcue S Egozcue J Barri PN 《Human reproduction (Oxford, England)》1999,14(2):375-378
The incidence of meiotic abnormalities and their relationship with different spermatogenic parameters was assessed in 103 male patients with presumably idiopathic severe oligoasthenozoospermia (motile sperm concentration < or = 1.5 x 10(6)/ml). Meiosis on testicular biopsies was independently evaluated by two observers. Meiotic patterns included normal meiosis and two meiotic abnormalities, i.e. severe arrest and synaptic anomalies. A normal pattern was found in 64 (62.1%), severe arrest in 21 (20.4%) and synaptic anomalies in 18 (17.5%). The overall rate of meiotic abnormalities was 37.9%. Most (66.7%) meiotic abnormalities occurred in patients with a sperm concentration < or = 1 x 10(6)/ml. In this group, total meiotic abnormalities were found in 57.8% of the patients; of these, 26.7% had synaptic anomalies. When the sperm concentration was < or = 0.5 x 10(6)/ml, synaptic anomalies were detected in 40% of the patients. In patients with increased follicle stimulating hormone (FSH) concentrations, total meiotic abnormalities occurred in 54.8% (synaptic anomalies in 22.6%). There were statistically significant differences among the three meiotic patterns in relation to sperm concentration (P < 0.001) and serum FSH concentration (P < 0.05). In the multivariate analysis, sperm concentration < or = 1 x 10(6)/ml and/or FSH concentration > 10 IU/l were the only predictors of meiotic abnormalities. 相似文献
47.
Jonas M. Weissbrod Rakesh K. Jain Francis M. Sirotnak 《Journal of pharmacokinetics and pharmacodynamics》1978,6(6):487-503
A lumped compartmental model has been derived to predict methotrexate concentration as a function of time for L1210 cells in BD2F
1
female mice at doses ranging from 3 mg/kg to 400 mg/kg. Using standard methods of parameter estimation as well as experimental determinations, an integrated approach was derived to account for the differences between the subcutaneous (s.c.) and intraperitoneal (i.p.) modes of injection. It was found that a single generalized forcing function can be used to fit plasma concentration after s.c. injection for all doses. Adequate fits (average error<20% while the standard deviation of experimental determinations was±22%) of L1210 cell data after s.c. injection were obtained. The best results were for a maximum facilitated influx constant Vmax
of 0.424 g/min/ml, a Michaelis influx constant Km
of 1,42 g/ml, and a first-order efflux constant of 0.047 min–1.The model simulations were not sensitive to Vmax, Km,and so long as the ratio Vmax/was approximately 9g/ml. The values of V
max
,K
m
,and which were obtained from our analysis of the in vivodata can be explained on the basis of previously performed in vitroexperiments. The parameters obtained from modeling the s.c. data were then applied for i.p. injection data. The resulting fits were adequate (average error<20% while the standard deviation of experimental determinations was±22%). A single generalized forcing function for drug concentration in the peritoneal cavity after i.p. injection for all doses was derived. The application of these results enables the prediction of methotrexate concentration in neoplastic cells at other doses after either s.c. or i.p. injection. 相似文献
48.
Wouterlood FG 《The European journal of neuroscience》1991,3(7):641-647
The innervation of dendrites of identified entorhinal principal cells by fibres originating in the nucleus reuniens thalami was studied in the rat. The lectin Phaseolus vulgaris-leucoagglutinin (PHA-L, anterograde tracer) was injected into the nucleus reuniens and the fluorescent dye Fast Blue (retrograde tracer) into the hippocampus. After survival, perfusion-fixation and the preparation of brain slices, entorhinal neurons retrogradely labelled with Fast Blue were intracellularly injected with the dye Lucifer yellow to introduce a specific marker into their dendrites. The transported PHA-L and the injected Lucifer yellow were visualized through dual peroxidase immunohistochemistry. Varicosities on PHA-L labelled reuniens fibres abut ascending and descending Lucifer yellow-filled secondary dendrites of multipolar and pyramidal principal entorhinal neurons that possess either spiny or sparsely spiny dendrites, but they do not appose the perikarya of these cells. In the electron microscope, PHA-L labelled boutons in the entorhinal cortex were observed forming asymmetrical synaptic contacts with dendritic spines (50%) or shafts (50%). The results indicate that direct thalamic input occurs on dendrites of neurons in the entorhinal cortex which project to the hippocampus. 相似文献
49.
罗通定中降解物巴马汀限量检测方法 总被引:4,自引:0,他引:4
目的:研究解决罗通定及硫酸罗通定注射液中降解物巴马汀的检测方法。方法:用薄层色谱法和紫外分光光度法限量检查样品中的巴马汀。结果:与对照品斑点大小、荧光强度比较和用吸收度限值控制均可对样品中的巴马汀进行限量检查,结果与原标准一致。结论:两方法均灵敏,专属,简便,快速。 相似文献
50.