全文获取类型
收费全文 | 10071篇 |
免费 | 959篇 |
国内免费 | 77篇 |
专业分类
耳鼻咽喉 | 60篇 |
儿科学 | 280篇 |
妇产科学 | 183篇 |
基础医学 | 1341篇 |
口腔科学 | 263篇 |
临床医学 | 1133篇 |
内科学 | 1728篇 |
皮肤病学 | 207篇 |
神经病学 | 1058篇 |
特种医学 | 604篇 |
外科学 | 1428篇 |
综合类 | 304篇 |
一般理论 | 6篇 |
预防医学 | 1021篇 |
眼科学 | 239篇 |
药学 | 843篇 |
中国医学 | 13篇 |
肿瘤学 | 396篇 |
出版年
2023年 | 48篇 |
2022年 | 51篇 |
2021年 | 157篇 |
2020年 | 100篇 |
2019年 | 171篇 |
2018年 | 194篇 |
2017年 | 156篇 |
2016年 | 133篇 |
2015年 | 178篇 |
2014年 | 224篇 |
2013年 | 343篇 |
2012年 | 551篇 |
2011年 | 543篇 |
2010年 | 266篇 |
2009年 | 286篇 |
2008年 | 489篇 |
2007年 | 534篇 |
2006年 | 572篇 |
2005年 | 515篇 |
2004年 | 470篇 |
2003年 | 421篇 |
2002年 | 402篇 |
2001年 | 271篇 |
2000年 | 225篇 |
1999年 | 245篇 |
1998年 | 175篇 |
1997年 | 167篇 |
1996年 | 143篇 |
1995年 | 125篇 |
1994年 | 109篇 |
1993年 | 119篇 |
1992年 | 184篇 |
1991年 | 186篇 |
1990年 | 150篇 |
1989年 | 191篇 |
1988年 | 163篇 |
1987年 | 177篇 |
1986年 | 146篇 |
1985年 | 158篇 |
1984年 | 111篇 |
1983年 | 110篇 |
1982年 | 74篇 |
1981年 | 69篇 |
1980年 | 82篇 |
1979年 | 99篇 |
1978年 | 71篇 |
1977年 | 78篇 |
1976年 | 54篇 |
1975年 | 59篇 |
1974年 | 66篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Huang Y Duncan AA McKusick MA Milliner DS Bower TC Kalra M Gloviczki P Hoskin TL 《Vascular and endovascular surgery》2007,41(6):490-499
Between 1986 and 2005, 22 patients (mean age, 14.7 years; range, 3-21) with renal hypertension underwent renal artery revascularization for 28 lesions, 23 with open repair (OR) and 5 with percutaneous transluminal renal angioplasty (PTRA). Thirty-day morbidity was 17% (4/23). Hypertension was cured in 13 (57%), improved in 8 (38%), and unchanged in 1 (5%). Renal function worsened in 1. At a mean follow-up of 4.9 years, 1-year patency rate was 94% and maintained for 5 years. Hypertension at 1 year was cured in 6 of 14 patients (43%; OR, 4; PTRA, 2) and improved in 8 (57%; OR, 7; PTRA, 1); hypertension at 5 years was cured in 50% and improved in 50%. Renal function remained unchanged in all patients who were followed. The authors conclude that both OR and PTRA benefit pediatric patients. PTRA for selected patients may be promising as a first line treatment or as a bridge to definitive OR in children with small arteries. 相似文献
992.
A retrospective chart review for the period between 1998 and 2006 was conducted to evaluate microneurolysis combined with
a hypothenar fat pad flap (HTFPF) for patients at Mayo Clinic, Scottsdale, Arizona, who were being treated for recurrent carpal
tunnel syndrome. After exclusion of patients with incomplete release of the transverse carpal ligament at the time of the
original operation, 28 consecutive patients were identified. Their average age was 68.5 years (range 43–89 years). The average
interval between the original carpal tunnel release and reexploration was 82 months (range 5–298 months). The average follow-up
was 10.5 months (range 3–48.4 months). The preoperative two-point discrimination tests averaged 7 mm (range 5–12 mm). At surgery,
all patients were found to have fibrosis surrounding the median nerve with adherence of the nerve to the radial leaf of the
transverse carpal ligament. After surgery, the Tinel sign disappeared in 26 of 28 patients and two-point discrimination improved
to an average of 6 mm (range 4–8 mm). Postoperative grip strength averaged 20 kg, compared with 11 kg preoperatively. Pain
completely disappeared in 83% of patients (average improvement 93%, range 5–100%). Numbness completely disappeared in 42%
of patients (average improvement 82.9%, range 5–100%). Tingling disappeared in 50% of patients (average improvement 84.7%,
range 5–100%). No patient reported being worse after reoperation. These results suggest that the combination of microneurolysis
and HTFPF can restore median nerve gliding and provide soft-tissue coverage, improving symptoms in patients with recurrent
carpal tunnel syndrome.
Oral presentation at the 71st Annual Meeting of the American Academy of Orthopedic Surgeons, San Francisco, California, March
10–14, 2004.
Oral presentation at the 2005 Annual Meeting of the American Association for Hand Surgery, Fajardo, Puerto Rico, January 12–15,
2005.
Poster presentation at the 60th Annual Meeting of the American Society for Surgery of the Hand, San Antonio, Texas, September
22–24, 2005. 相似文献
993.
994.
995.
Mary Katherine Waibel‐Duncan PhD Eleanor Benner Meghan Weeks 《Journal of child and adolescent psychiatric nursing》2012,25(2):91-95
TOPIC: Y.O.O. Rock Columbia County Youth Outreach Opportunities for Families Children, and Youth ( Waibel‐Duncan & Gillam, 2009 ) represents our nonurban county's first organized effort to systematically identify and promote awareness of volunteer and outreach opportunities for families, children, and youth. PURPOSE: In addition to describing Y.O.O. Rock's development, this article summarizes feedback from parents, professionals, and paraprofessionals and outlines their recommendations for the second edition of the guide. SOURCE: Issue briefs from the Corporation for National & Community Service (2005, 2006, 2008 ) suggest the need for reference guides like Y.O.O. Rock insofar as they document limited volunteer and outreach opportunities for young children as well as the family's role in engaging children in service to others. CONCLUSION: This article will inform others who seek to increase families', children's, and youth's awareness of volunteer activities and outreach opportunities in their communities. 相似文献
996.
Katherine Wander Bettina Shell‐Duncan Thomas W. McDade 《American journal of human biology》2009,21(2):172-179
An evolutionary perspective suggests that iron deficiency may have opposing effects on infectious disease risk, decreasing susceptibility by restricting iron availability to pathogens, and increasing susceptibility by compromising cellular immunocompetence. In some environments, the trade‐off between these effects may result in optimal iron intake that is inadequate to fully meet body iron needs. Thus, it has been suggested that moderate iron deficiency may protect against acute infection, and may represent a nutritional adaptation to endemic infectious disease stress. To test this assertion, we examined the association between infection, reflected by C‐reactive protein, a biomarker of inflammation, and iron status, reflected by transferrin receptor (TfR) and zinc protoporphyrin to heme ratio (ZPP:H), among school‐age Kenyan children, and evaluated the hypothesis that moderate iron deficiency is associated with lower odds of infectious disease. TfR > 5.0 mg/l, with sensitivity and specificity for iron deficiency (ZPP:H > 80 μmol/mol) of 0.807 and 0.815, was selected as the TfR definition of iron deficiency. Controlling for age and triceps skinfold thickness (TSF), the odds ratio (OR) for acute viral or bacterial infection associated with iron deficiency (compared to normal/replete) was 0.50 (P = 0.11). Controlling for age and TSF, the OR for infection associated with an unequivocally iron replete state (compared to all others) was 2.9 (P = 0.01). We conclude that iron deficiency may protect against acute infection in children. Am. J. Hum. Biol, 2009. © 2008 Wiley‐Liss, Inc. 相似文献
997.
The classical twin design (CTD) uses observed covariances from monozygotic and dizygotic twin pairs to infer the relative magnitudes of genetic and environmental causes of phenotypic variation. Despite its wide use, it is well known that the CTD can produce biased estimates if its stringent assumptions are not met. By modeling observed covariances of twins’ relatives in addition to twins themselves, extended twin family designs (ETFDs) require less stringent assumptions, can estimate many more parameters of interest, and should produce less biased estimates than the CTD. However, ETFDs are more complicated to use and interpret, and by attempting to estimate a large number of parameters, the precision of parameter estimates may suffer. This paper is a formal investigation into a simple question: Is it worthwhile to use more complex models such as ETFDs in behavioral genetics? In particular, we compare the bias, precision, and accuracy of estimates from the CTD and three increasingly complex ETFDs. We find the CTD does a decent job of estimating broad sense heritability, but CTD estimates of shared environmental effects and the relative importance of additive versus non-additive genetic variance can be biased, sometimes wildly so. Increasingly complex ETFDs, on the other hand, are more accurate and less sensitive to assumptions than simpler models. We conclude that researchers interested in characterizing the environment or the makeup of genetic variation should use ETFDs when possible. 相似文献
998.
A study on the impact of catharanthine C10 and C12 indole substituents on the biomimetic Fe(III)-mediated coupling with vindoline led to the discovery and characterization of two new and substantially more potent derivatives, 10'-fluorovinblastine and 10'-fluorovincristine. In addition to defining a pronounced and unanticipated substituent effect on the biomimetic coupling, fluorine substitution at C10', which minimally alters the natural products, was found to uniquely enhance the activity 8-fold against both sensitive (IC(50) = 800 pM, HCT116) and vinblastine-resistant tumor cell lines (IC(50) = 80 nM, HCT166/VM46). As depicted in the X-ray structure of vinblastine bound to tubulin, this site resides at one end of the upper portion of the T-shaped conformation of the tubulin-bound molecule, suggesting the 10'-fluorine substituent makes critical contacts with the protein at a hydrophobic site uniquely sensitive to steric interactions. 相似文献
999.
R. Paul Duncan Christy H. Lemak W. Bruce Vogel Christopher E. Johnson Allyson G. Hall Colleen K. Porter 《Health services research》2008,43(1P2):384-400
Research Objective. To evaluate the design, development, and implementation of Florida's Medicaid provider service network (PSN) demonstration, and the implications of that demonstration for subsequent Medicaid Reform in Florida.
Data Sources, Data Collection. Organizational analyses were based on archival and enrollment data obtained from Florida's Medicaid program and the South Florida Community Care Network, as well as key informant interviews. Closely related fiscal analyses utilized Medicaid claims data from March 1999 through October 2001 extracted from the Florida Medicaid Management Information System.
Study Design. The organizational analyses reported here were based on a structured case study research design.
Principal Findings. Almost every aspect of the development of the new organizational form (PSN) took longer and was more difficult than anticipated. Prior organizational experience with insurance functions proved to be an asset. While fiscal analyses indicated that the program saved the state of Florida a significant amount of money, tracking the precise origin of the savings proved to be challenging.
Conclusions. By most standards, the PSN program was observed to meet its stated objectives. Based in part on this conclusion, the state chose to extend the use of PSNs within its 2006 Medicaid Reform initiative. 相似文献
Data Sources, Data Collection. Organizational analyses were based on archival and enrollment data obtained from Florida's Medicaid program and the South Florida Community Care Network, as well as key informant interviews. Closely related fiscal analyses utilized Medicaid claims data from March 1999 through October 2001 extracted from the Florida Medicaid Management Information System.
Study Design. The organizational analyses reported here were based on a structured case study research design.
Principal Findings. Almost every aspect of the development of the new organizational form (PSN) took longer and was more difficult than anticipated. Prior organizational experience with insurance functions proved to be an asset. While fiscal analyses indicated that the program saved the state of Florida a significant amount of money, tracking the precise origin of the savings proved to be challenging.
Conclusions. By most standards, the PSN program was observed to meet its stated objectives. Based in part on this conclusion, the state chose to extend the use of PSNs within its 2006 Medicaid Reform initiative. 相似文献
1000.
Boris P. Ehrenstein MD Julita Mir MD Robert A. Duncan MD MPH John R. Stram MD Carl J. O'Hara MD Donald E. Craven MD 《Comprehensive therapy》2000,26(1):25-30
Painless, bilateral parotid enlargement due to benign lymphoepithelial cysts is an often unrecognized manifestation of HIV-type
1 infection. Diagnosis can be made clinically and confirmed by tests. Medical treatment with combination antiretroviral therapy
is the cornerstone of current medical management. 相似文献