全文获取类型
收费全文 | 67917篇 |
免费 | 4957篇 |
国内免费 | 192篇 |
专业分类
耳鼻咽喉 | 833篇 |
儿科学 | 1962篇 |
妇产科学 | 1403篇 |
基础医学 | 8937篇 |
口腔科学 | 818篇 |
临床医学 | 7556篇 |
内科学 | 13742篇 |
皮肤病学 | 764篇 |
神经病学 | 6577篇 |
特种医学 | 2102篇 |
外科学 | 9786篇 |
综合类 | 1216篇 |
现状与发展 | 1篇 |
一般理论 | 121篇 |
预防医学 | 6949篇 |
眼科学 | 828篇 |
药学 | 4397篇 |
中国医学 | 75篇 |
肿瘤学 | 4999篇 |
出版年
2023年 | 559篇 |
2022年 | 973篇 |
2021年 | 2113篇 |
2020年 | 1256篇 |
2019年 | 1988篇 |
2018年 | 2214篇 |
2017年 | 1560篇 |
2016年 | 1754篇 |
2015年 | 1992篇 |
2014年 | 2607篇 |
2013年 | 3496篇 |
2012年 | 5647篇 |
2011年 | 5653篇 |
2010年 | 3069篇 |
2009年 | 2658篇 |
2008年 | 4524篇 |
2007年 | 4517篇 |
2006年 | 4419篇 |
2005年 | 4340篇 |
2004年 | 3840篇 |
2003年 | 3501篇 |
2002年 | 3145篇 |
2001年 | 506篇 |
2000年 | 380篇 |
1999年 | 500篇 |
1998年 | 658篇 |
1997年 | 521篇 |
1996年 | 419篇 |
1995年 | 394篇 |
1994年 | 330篇 |
1993年 | 312篇 |
1992年 | 262篇 |
1991年 | 223篇 |
1990年 | 209篇 |
1989年 | 189篇 |
1988年 | 179篇 |
1987年 | 154篇 |
1986年 | 146篇 |
1985年 | 149篇 |
1984年 | 164篇 |
1983年 | 136篇 |
1982年 | 175篇 |
1981年 | 190篇 |
1980年 | 123篇 |
1979年 | 84篇 |
1978年 | 86篇 |
1977年 | 81篇 |
1976年 | 65篇 |
1975年 | 62篇 |
1973年 | 60篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Raymond Tubbs James Pettay Richard Powell David G Hicks Patrick Roche William Powell Thomas Grogan James F Hainfeld 《Applied immunohistochemistry & molecular morphology》2005,13(4):371-375
Ultrasensitive bright field in situ hybridization assays using enzyme metallography (EnzMet) have been developed and validated, but little is known regarding the applicability of EnzMet for immunophenotypic detection of protein via IHC. Superior resolution via discrete metallographic deposits offers the potential for enhancing high-resolution immunophenotyping. Using high-complexity tissue microarrays (TMAs), 88 common solid tumors were evaluated by automated EnzMet (Nanoprobes and Ventana). Targets were chosen to assess the ability of EnzMet to specifically localize encoded antigens in the nucleus (estrogen receptor), cytoplasm (cytokeratins), and cytoplasmic membrane (HER2) in TMAs. Results were compared with conventional IHC diaminobenzidine (DAB) immunostaining. There was full concordance between the EnzMet and conventional IHC results. Furthermore, the EnzMet reaction products did not appreciably diffuse, were dense and sharply defined, and provided excellent high-resolution differentiation of cellular compartments in paraffin sections for the nuclear, cytoplasmic, and cell membrane-localized antigens evaluated. The higher density of elemental silver deposited during enzyme metallography permitted evaluation of core immunophenotypes at a relatively low magnification, allowing more tissue to be screened in an efficient manner. This preliminary study shows the utility of using enzyme metallography for high-resolution immunophenotyping in TMAs. 相似文献
43.
Philip S Wells Josdalyne L Anderson Marc A Rodger Nancy Carson Rebecca L Grimwood Steve P Doucette 《Blood coagulation & fibrinolysis》2006,17(7):533-538
The substitution of leucine for valine at amino acid position 34 of the factor XIII gene is commonly referred to as FXIII Val34Leu polymorphism. The homozygous leucine/leucine genotype has been reported to confer protection against venous thromboembolism, but previous studies have not evaluated a population limited to those with idiopathic venous thromboembolism. The primary objective of the study was to determine whether the FXIII Val34Leu polymorphism is independently associated with the occurrence of idiopathic venous thromboembolism. We prospectively enrolled consecutive patients with at least one objectively confirmed idiopathic venous thromboembolism. Friends of cases were recruited as controls and matched to cases by sex, ethnicity, and age. All participants were tested for the FXIII Val34Leu polymorphism in addition to several well-known thrombophilias. Data from 309 cases and 306 controls were analyzed. The FXIII leucine/leucine genotype was present in 4.9% of cases and 6.5% of controls. An adjusted odds ratio of 0.59 (95% confidence interval, 0.25-1.38) was found for the recessive model and 0.69 (95% confidence interval, 0.46-1.02) for the dominant model. Our results do not support an independent association of the FXIII Val34Leu polymorphism with idiopathic venous thromboembolism in our Caucasian Canadian study population. 相似文献
44.
Rakel Kling Marc Corbière Rebecca Milord Janet G Morrison Kevin Craib Annalee Yassi Claire Sidebottom Catherine Kidd Victoria Long Sharon Saunders 《AAOHN journal》2006,54(11):481-487
This study examined the use and effectiveness of the Alert assessment form. The form is part of the Alert system, used by one large acute care hospital to identify patients with a propensity for violence. All reported incidents of patient violence from August 1, 2003, through December 31, 2004, were included in patient charts. One hundred seventeen violent patient charts were reviewed and compared with 161 non-violent patient charts, randomly chosen from the same time period. Overall use of the Alert assessment form for violent and non-violent patients was 75.7% and 35.4%, respectively. The assessment form was found to have moderate sensitivity (71%) and high specificity (94%). It is reasonably effective in identifying potentially violent or aggressive patients when it is used according to protocol. Efforts to improve the tool are warranted, as is evaluation of its benefit in settings with low prevalence of violence. Also, greater effort must be taken to prevent violence once an aggressive patient has been identified. 相似文献
45.
Belinda Joy Deal Rebecca A Fountain Carol Ann Russell-Broaddus Melinda Stanley-Hermanns 《Disaster Management & Response》2006,4(4):100-105
Hurricanes Katrina and Rita forced many individuals along the coast of Texas and Louisiana to seek shelter inland. Among the evacuees were residents with special needs and residents of nursing homes and group homes caring for mentally retarded and physically disabled persons. Many nurses volunteered to provide health care for those in need. This article discusses challenges and opportunities that were encountered by nurses volunteering in special-needs shelters. Issues related to human and physical resources, patient care, and confidentiality are discussed including lessons learned. As nurses who cared for evacuees in the shelter, it is hoped some of the lessons learned can be utilized in future disasters. 相似文献
46.
Marvin Rubenstein Robert Saffrin Michael Shaw Sergey Muchnik Patrick Guinan 《The Prostate》1995,27(3):148-153
Orthotopic placement of in vitro propagated Dunning R3327 AT-3 tumor cells resulted in a greater percentage of tumor takes and a two-fold shift in the exponential growth curve compared to flank implantation. The orthotopic tumor appeared to disseminate preferentially to regional lymph nodes, rather than to the lungs which is characteristic of flank tumors. The results suggest an important role of stromal-epithelial interactions in the growth of this tumor. © 1995 Wiley-Liss, Inc. 相似文献
47.
A series of 5-alkyl-5-phenylbarbituric acid analogues were shown to be potent hypolipidemic agents in rats and mice at 20 mg/kg/day. This dose is lower than that required for hypolipidemic activity for clofibrate and nicotinic acid derivatives in rodents and man. These new derivatives reduced both serum cholesterol and triglyceride levels in rodents by either the oral or intraperitoneal route of administration. Previous studies have demonstrated that similar heterocyclic compounds, i.e. cyclic imides, glutarimides and hydantoins are potent hypolipidemic agents in rodents. The barbituric acid derivatives probably interfered with de novo synthesis of cholesterol and fatty acids in the early steps since the agents inhibit the activities of ATP-dependent citrate lyase and acetyl-CoA synthetase. Triglyceride synthesis may be blocked since the agents inhibited the rate limiting enzyme, sn-glycerol-3-phosphate-acyl-transferase. Rat tissue lipids especially cholesterol and triglycerides were reduced after 14 days treatment. Fecal lipids were increased in cholesterol and phospholipid content by selected compounds. The rat serum lipoprotein after 14 days drug administration showed reduced VLDL-cholesterol and HDL-triglyceride contents. The modulation of the lipid content of the serum lipoproteins by the barbituric acids suggest that these agents may be helpful in treating clinical hyperlipidemic disease states. 相似文献
48.
Poverty, health services, and health status in rural America 总被引:5,自引:0,他引:5
Access to health services for everyone has been a major policy goal in the United States: inequitable access is assumed to lead to inequitable health status, particularly for low-income groups. A sophisticated model of the relation between poverty, health care needs, service use, and health outcomes is used to analyze cross-sectional data on 7,823 adults from 36 rural communities. Improved access and use are helpful, but evidence clearly indicates that combined health and social initiatives will be necessary to reduce inequalities in health status. 相似文献
49.
Edel A. O'Toole MRCPI Patrick Deasy FRCPI † Rosemarie Watson FRCPI FACP 《Pediatric dermatology》1995,12(4):348-350
Abstract: We report a patient with cutis marmorata telangiectatica with the hitherto unreported anomaly of a double aortic arch. The presence of two major vascular anomalies in this patient may be secondary to a developmental defect of the mesoderm during embryogenesis. 相似文献
50.
R. N. Sinha A. W. Patrick L. Richardson M. Wallymahmed I. A. MacFarlane 《Postgraduate medical journal》1997,73(859):293-294
One hundred insulin-dependent diabetic patients (age < 45 years, 53 smokers) were followed for six years. The age, duration of diabetes and mean glycated haemoglobin levels, were comparable between the smokers and non-smokers. Microvascular complications (retinopathy and increased urine albumin excretion) were commoner and more severe in the smoking group at six years, particularly in heavy smokers. Of the 45 original smokers reviewed at six years, 12 (27%) had stopped, six of whom had developed microvascular complications. Only two of the ''heavy'' initial smokers, likely to be at most risk, had stopped smoking, and three original non-smokers had started smoking. 相似文献