全文获取类型
收费全文 | 12746篇 |
免费 | 1530篇 |
国内免费 | 263篇 |
专业分类
耳鼻咽喉 | 69篇 |
儿科学 | 196篇 |
妇产科学 | 125篇 |
基础医学 | 1526篇 |
口腔科学 | 275篇 |
临床医学 | 1050篇 |
内科学 | 2342篇 |
皮肤病学 | 141篇 |
神经病学 | 841篇 |
特种医学 | 320篇 |
外国民族医学 | 2篇 |
外科学 | 547篇 |
综合类 | 1199篇 |
一般理论 | 3篇 |
预防医学 | 3513篇 |
眼科学 | 206篇 |
药学 | 1358篇 |
2篇 | |
中国医学 | 169篇 |
肿瘤学 | 655篇 |
出版年
2024年 | 23篇 |
2023年 | 249篇 |
2022年 | 268篇 |
2021年 | 553篇 |
2020年 | 554篇 |
2019年 | 516篇 |
2018年 | 462篇 |
2017年 | 521篇 |
2016年 | 508篇 |
2015年 | 591篇 |
2014年 | 878篇 |
2013年 | 1086篇 |
2012年 | 843篇 |
2011年 | 881篇 |
2010年 | 697篇 |
2009年 | 674篇 |
2008年 | 672篇 |
2007年 | 682篇 |
2006年 | 563篇 |
2005年 | 436篇 |
2004年 | 404篇 |
2003年 | 316篇 |
2002年 | 280篇 |
2001年 | 273篇 |
2000年 | 212篇 |
1999年 | 171篇 |
1998年 | 173篇 |
1997年 | 140篇 |
1996年 | 136篇 |
1995年 | 98篇 |
1994年 | 81篇 |
1993年 | 74篇 |
1992年 | 82篇 |
1991年 | 67篇 |
1990年 | 45篇 |
1989年 | 32篇 |
1988年 | 42篇 |
1987年 | 25篇 |
1986年 | 29篇 |
1985年 | 38篇 |
1984年 | 23篇 |
1983年 | 16篇 |
1982年 | 19篇 |
1981年 | 19篇 |
1980年 | 20篇 |
1979年 | 12篇 |
1978年 | 9篇 |
1977年 | 17篇 |
1976年 | 7篇 |
1975年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
61.
When excluding haemophilia and von Willebrand disease, coagulation factors deficiencies constitute rare autosomal recessive disorders (<1 in 500,000) of less precisely defined epidemiology. We have reported herein the distribution of these entities in the French Basque Country, a genetic isolate of very old individualization with peculiar biological specificities. The prevalence of these disorders was markedly high, especially, as already shown, factor XI deficiency. This unusual profile needs to be discussed in the view of population genetics. 相似文献
62.
Donald B. White Cynthia A. Walawander Dong Y. Liu Thaddeus H. Grasela 《Journal of pharmacokinetics and pharmacodynamics》1992,20(3):295-313
In a simulation study of inference on population pharmacokinetic parameters, two methods of performing tests of hypotheses comparing two populations using NONMEM were evaluated. These two methods are the test based upon 95% confidence intervals and the likelihood ratio test. Data were simulated according to a monoexponential model and, in that context, power curves for each test were generated for (i)the ratio of mean clearance and (ii)the ratio of the population standard deviations of clearance. To generate the power curves, a range of these parameters was employed; other pharmacokinetic parameters were selected to reflect the variability typically present in a Phase II clinical trial. For tests comparing the means, the confidence interval tests had approximately the same power as the likelihood ratio tests and were consistently more faithful to the nominal level of significance. For comparison of the standard deviations, and when the volume of information available was relatively small, however, the likelihood ratio test was more able to detect differences between the two groups. These results were then compared to results on parameter estimation in order to gain insight into the question of power. As an example, the nonnormality of estimates of the ratio of standard deviations plays an important role in explaining the low power for the confidence interval tests. We conclude that, except for the situation of modeling standard deviations with only sparse information, NONMEM produces tests of significance that are effective at detecting clinically significant differences between two populations.Partial support from the Upjohn Company, NIH-BRSG SO RR 07066, and the Burroughs Wellcome Foundation. 相似文献
63.
Complex segregation analyses of bone mineral density in Chinese 总被引:3,自引:1,他引:2
China has the largest population in the world; approximately 7% of the total population suffers from primary osteoporosis. Osteoporosis is mainly characterized by low bone mineral density (BMD). In the present study, familial correlation and segregation analyses for spine and hip BMDs have been undertaken for the first time in a Chinese sample composed of 401 nuclear families with a total of 1,260 individuals. The results indicate a major gene of additive inheritance for hip BMD, whereas there is no evidence of a major gene influencing spine BMD. Significant familial residual effects are found for both traits, and heritability estimates (±SE) for spine and hip BMDs are 0.807(0.099) and 0.897(0.101), respectively. Sex and age differences in genotype‐specific average BMD are also observed. This study provides the first evidence quantifying the high degree of genetic determination of BMD variation in the Chinese. 相似文献
64.
R. Jiménez M. D. González M. A. Pérez J. A. García 《Ophthalmic & physiological optics》2003,23(2):97-107
The evolution of the accommodative function and development of ocular movement are evaluated in a non-clinical paediatric population (1056 subjects) aged 6-12 years, providing means for each age in the optometric tests that evaluate the accommodative amplitude, accommodative facility, accommodative response (lag), and saccadic movements. A comparison of these values between ages (anova) established three distinct trends in the behaviour of these parameters. The accommodative amplitude, measured by modified dynamic retinoscopy, and the evaluation of the saccadic movements by the development of ocular movements [developmental eye movement (DEM)] test showed continuous change with age. The values for monocular and binocular accommodative facility, measured by +/-2.00 D flippers, indicated the need to divide the population into two age groups (6-7 and 8-12 years). Finally, the means of accommodative response, measured by monocular estimation model (MEM) retinoscopy, and the direct observation of saccadic movement revealed no significant differences between ages, establishing a single mean reference value for the age group studied. 相似文献
65.
66.
对全国部分城乡家鼠鼠情监测三年结果的分析表明:城乡家鼠组成均以三大家鼠(褐家鼠、小家鼠、黄胸鼠)为主,其次为食虫目臭鼩鼱~#和黑线姬鼠。五种主要鼠种在家鼠组成中的数量比基本稳定,但三年中城乡少数鼠种间的顺位有所变化。监测结果亦表明,五种主要鼠种的地区分布是:褐家鼠、小家鼠遍布所有监测的省、市、区,同以往文献中遍布全国的说法一致;黄胸鼠分布于黄河以南;食虫目中的臭鼩鼱分布于华中区以南的广大地区。这在以往文献中均已有记载,但以往文献有关黄胸鼠和臭鼩鼱分布的其他说法,则被证实为不确切的。黑线姬鼠的分布范围已超过以往文献中关于分布于东北、华北及长江流域的说法,但以往文献中关于该鼠种遍及全国的说法是否正确,则有待进一步证实。 相似文献
67.
Yukiya Hashimoto Toshiko Koue Yuko Otsuki Masato Yasuhara Ryohei Hori Ken-ichi Inui 《Journal of pharmacokinetics and pharmacodynamics》1995,23(2):205-216
A simulation study was conducted to compare the cost and performance of various models for population analysis of the steady
state pharmacokinetic data arising from a one-compartment model with Michaelis-Menten elimination. The usual Michaelis-Menten
model (MM) and its variants provide no estimate of the volume of distribution, and generally give poor estimates of the maximal
elimination rate and the Michaelis-Menten constant. The exact solution to the Michaelis-Menten differential equation (TRUE)
requires a precise analysis method designed for estimation of population pharmacokinetic parameters (the first-order conditional
estimation method) and also considerable computational time to estimate population mean parameters accurately. The one-compartment
model with dose-dependent clearance (DDCL), in conjunction with the first-order conditional estimation or Laplacian method,
ran approximately 20-fold faster than TRUE and gave accurate population mean parameters for a drug having a long biological
half-life relative to the dosing interval. These findings suggest that the well-known MM and its variants should be used carefully
for the analysis of blood concentrations of a drug with Michaelis-Menten elimination kinetics, and that TRUE, in conjunction
with a precise analysis method, should be considered for estimating population pharmacokinetic parameters. In addition, DDCL
is a promising alternative to TRUE with respect to computation time, when the dosing interval is short relative to the biological
half-life of a drug.
This work was supported in part by the Epilepsy Research Foundation, the Nakatomi Foundation, and a Grant-in-Aid for Scientific
Research from the Ministry of Education, Science, and Culture of Japan. 相似文献
68.
Stem cells of the adult kidney: where are you from? 总被引:1,自引:0,他引:1
Takahito Ito 《Nephrology, dialysis, transplantation》2003,18(4):641-644
69.
天津市和平区354名老年人生活质量调查分析 总被引:20,自引:0,他引:20
目的 了解老年人的生存质量。方法 以健康状况调查问卷SF—36对天津市和平区新兴街354名印岁以上的老人进行调查。结果 天津市新兴街老年人的生活质量水平较高,但经济状况和慢性疾病是影响老年人生活质量的两个重要因素。结论 改善老年人的经济状况,预防和延缓老年性疾病的发生是提高老年人生活质量的重要措施。 相似文献
70.
目的:探讨地衣芽胞杆菌C01在模型小鼠体内对大肠杆菌、沙门氏菌抑制作用以及对乳杆菌等有益菌的促进作用。方法:用地衣芽胞杆菌C01灌胃肠道感染模型小鼠,采用体外活菌培养,分析粪便菌群数量的变化。结果:C01灌胃治疗组(EPEC C01)中乳杆菌的数量显著高于EPEC灌胃模型组(EPEC N)(P<0.01),肠杆菌数量下降极显著(P<0.01),而(EPEC N)组肠杆菌数显著高于正常对照组(NS)(P<0.05);肠炎沙门氏菌处理后C01灌胃治疗组(SL C01)和处理后肠炎沙门氏模型组(SL N)比较,乳杆菌、肠球菌和总厌氧菌的变化不明显,但肠杆菌数量下降极显著(P<0.01);形态病理学观察结果显示,C01芽胞杆菌灌胃治疗组肠粘膜病变明显减轻,肠粘膜及绒毛高度明显增加,绒毛轻度水肿,绒毛排列整齐、致密。结论:地衣芽胞杆菌C01在体内对肠炎沙门氏菌和致病性大肠杆菌有较强的抑制作用,能促进乳杆菌等生理性有益菌的增殖,可保护肠粘膜结构的完整性免受病原菌的侵袭。 相似文献