全文获取类型
收费全文 | 23904篇 |
免费 | 1929篇 |
国内免费 | 1131篇 |
专业分类
耳鼻咽喉 | 239篇 |
儿科学 | 126篇 |
妇产科学 | 470篇 |
基础医学 | 811篇 |
口腔科学 | 170篇 |
临床医学 | 2109篇 |
内科学 | 1512篇 |
皮肤病学 | 234篇 |
神经病学 | 533篇 |
特种医学 | 539篇 |
外国民族医学 | 6篇 |
外科学 | 1593篇 |
综合类 | 4611篇 |
现状与发展 | 2篇 |
预防医学 | 939篇 |
眼科学 | 806篇 |
药学 | 7799篇 |
29篇 | |
中国医学 | 3838篇 |
肿瘤学 | 598篇 |
出版年
2024年 | 71篇 |
2023年 | 249篇 |
2022年 | 490篇 |
2021年 | 753篇 |
2020年 | 692篇 |
2019年 | 599篇 |
2018年 | 795篇 |
2017年 | 867篇 |
2016年 | 983篇 |
2015年 | 885篇 |
2014年 | 2005篇 |
2013年 | 1852篇 |
2012年 | 2075篇 |
2011年 | 2163篇 |
2010年 | 1616篇 |
2009年 | 1334篇 |
2008年 | 1219篇 |
2007年 | 1281篇 |
2006年 | 1166篇 |
2005年 | 1019篇 |
2004年 | 744篇 |
2003年 | 657篇 |
2002年 | 574篇 |
2001年 | 469篇 |
2000年 | 354篇 |
1999年 | 305篇 |
1998年 | 231篇 |
1997年 | 196篇 |
1996年 | 170篇 |
1995年 | 149篇 |
1994年 | 134篇 |
1993年 | 96篇 |
1992年 | 70篇 |
1991年 | 97篇 |
1990年 | 79篇 |
1989年 | 53篇 |
1988年 | 59篇 |
1987年 | 42篇 |
1986年 | 29篇 |
1985年 | 59篇 |
1984年 | 50篇 |
1983年 | 36篇 |
1982年 | 37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.
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
42.
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
43.
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
44.
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
45.
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
46.
47.
48.
49.
2001年—2003年第1季度北京地区门诊患者降血糖用药动态分析 总被引:4,自引:4,他引:4
目的 :了解北京地区糖尿病患者的用药需求 ,并对降血糖药物进行分析。方法 :采用《医院处方分析》课题 (北京地区 )2 0 0 1年~ 2 0 0 3年每年第 1季度门诊降血糖用药的处方数据进行比较。结果与结论 :通过统计 ,北京地区糖尿病患者人数不断增多 ,且人们更多选用了新型降糖药。在临床应用中 ,口服制剂以磺酰脲类用量居主导地位 ,而α-葡萄糖苷酶抑制剂用量逐年上升 ;使用基因合成人胰岛素较动物胰岛素的用量逐年增多 ,为控制糖尿病用药及合理应用提供了依据 相似文献
50.
穴位注射治疗周围性面神经麻痹及肌电图观察 总被引:1,自引:0,他引:1
目的 观察穴位注射治疗周围性面神经麻痹的疗效。方法 将 80例患者分为穴位注射组 5 0例和对照组 30例 ,穴位注射组采用维生素 B1 2 及维生素 B1 注射液穴位注射 ,对照组采用常规针刺 ,观察两组疗效及治疗前后面部肌电图变化。结果与结论 穴位注射组治愈率及愈显率明显高于对照组 (P<0 .0 5 ,P<0 .0 1) ,治疗后穴位注射组募集电位改善情况较对照组明显为优 (P<0 .0 5 ,P<0 .0 1)。 相似文献