全文获取类型
收费全文 | 4086篇 |
免费 | 380篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 49篇 |
儿科学 | 69篇 |
妇产科学 | 73篇 |
基础医学 | 607篇 |
口腔科学 | 54篇 |
临床医学 | 443篇 |
内科学 | 1031篇 |
皮肤病学 | 69篇 |
神经病学 | 351篇 |
特种医学 | 123篇 |
外科学 | 557篇 |
综合类 | 115篇 |
一般理论 | 5篇 |
预防医学 | 237篇 |
眼科学 | 80篇 |
药学 | 163篇 |
中国医学 | 6篇 |
肿瘤学 | 472篇 |
出版年
2023年 | 27篇 |
2022年 | 45篇 |
2021年 | 110篇 |
2020年 | 64篇 |
2019年 | 80篇 |
2018年 | 109篇 |
2017年 | 66篇 |
2016年 | 83篇 |
2015年 | 111篇 |
2014年 | 151篇 |
2013年 | 182篇 |
2012年 | 248篇 |
2011年 | 235篇 |
2010年 | 142篇 |
2009年 | 144篇 |
2008年 | 221篇 |
2007年 | 222篇 |
2006年 | 192篇 |
2005年 | 215篇 |
2004年 | 189篇 |
2003年 | 166篇 |
2002年 | 135篇 |
2001年 | 131篇 |
2000年 | 93篇 |
1999年 | 84篇 |
1998年 | 37篇 |
1997年 | 30篇 |
1996年 | 40篇 |
1995年 | 29篇 |
1994年 | 36篇 |
1993年 | 20篇 |
1992年 | 64篇 |
1991年 | 66篇 |
1990年 | 55篇 |
1989年 | 55篇 |
1988年 | 39篇 |
1987年 | 46篇 |
1986年 | 45篇 |
1985年 | 48篇 |
1984年 | 32篇 |
1983年 | 35篇 |
1982年 | 27篇 |
1981年 | 29篇 |
1980年 | 21篇 |
1979年 | 29篇 |
1978年 | 15篇 |
1976年 | 16篇 |
1972年 | 23篇 |
1937年 | 41篇 |
1936年 | 38篇 |
排序方式: 共有4504条查询结果,搜索用时 15 毫秒
41.
G.K. Balasubramani Richard K Zimmerman Heather Eng Jason Lyons Lloyd Clarke Mary Patricia Nowalk 《Vaccine》2021,39(8):1283-1289
BackgroundIn some settings, research methods to determine influenza vaccine effectiveness (VE) may not be appropriate because of cost, time constraints, or other factors. Administrative database analysis of viral testing results and vaccination history may be a viable alternative. This study compared VE estimates from outpatient research and administrative databases.MethodsUsing the test-negative, case-control design, data for 2017–2018 and 2018–2019 influenza seasons were collected using: 1) consent, specimen collection, RT-PCR testing and vaccine verification using multiple methods; and 2) an administrative database of outpatients with a clinical respiratory viral panel combined with electronic immunization records. Odds ratios for likelihood of influenza infection by vaccination status were calculated using multivariable logistic regression. VE = (1 ? aOR) × 100.ResultsResearch participants were significantly younger (P < 0.001), more often white (69% vs. 59%; P < 0.001) than non-white and less frequently enrolled through the emergency department (35% vs. 72%; P < 0.001) than administrative database participants. VE was significant against all influenza and influenza A in each season and both seasons combined (37–49%). Point estimate differences between methods were evident, with higher VE in the research database, but insignificant due to low sample sizes. When enrollment sites were separately analyzed, there were significant differences in VE estimates for all influenza (66% research vs. 46% administrative P < 0.001) and influenza A (67% research vs. 49% administrative; P < 0.001) in the emergency department.Conclusions:The selection of the appropriate method for determining influenza vaccine effectiveness depends on many factors, including sample size, subgroups of interest, etc., suggesting that research estimates may be more generalizable. Other advantages of research databases for VE estimates include lack of clinician-related selection bias for testing and less misclassification of vaccination status. The advantages of the administrative databases are potentially shorter time to VE results and lower cost. 相似文献
42.
A. Frilling W. Höppner C. Eng L. Mulligan F. Raue C. E. Broelsch 《Journal of molecular medicine (Berlin, Germany)》1995,73(5):229-233
Medullary thyroid carcinoma occurs sporadically or as a part of the inherited cancer syndrome multiple endocrine neoplasia (MEN) type 2. The MEN 2 gene has been identified as the RET proto-oncogene on chromosome 10. In MEN 2A, RET mutations are detectable in one of five cysteine codons within exons 10 and 11 and in MEN 2B in codon 918 (exon 16). Direct DNA testing for RET proto-oncogene mutations is the method of first choice in presymptomatic screening of MEN 2 families. Gene carriers should be offered prophylactic thyroidectomy. The process of DNA analysis for RET proto-oncogene mutations is demonstrated in one family with hereditary medullary thyroid carcinoma. RET mutations were detectable in five of the nine family members at risk.Abbreviations
MEN
Multiple endocrine neoplasia
-
MTC
Medullary thyroid carcinoma
-
FMTC
Familial medullary thyroid carcinoma
-
PCR
Polymerase chain reaction
-
C-cells
Calcitonin-producing parafollicular cells 相似文献
43.
Summary The Save Our Sisters Project builds on the roles of 95 natural helpers to increase mammography screening among older African American women in a NC county. Natural helpers are lay people to whom others naturally turn for advice, emotional support, and tangible aid. Findings from 14 focus group interviews showed that older women seek out these individuals when they have a female-specific concern, rather than or before seeking help from professionals. The characteristics of natural helpers, revealed in the findings, were used to identify and recruit them to become trained lay health advisors in breast cancer education. Through the SOS Project, natural helpers provide a community-based system of care and social support that complements the more specialized role of health professionals; linking them to women through places and ways that no health professional could begin to acquire. The three roles of lay health advisors are: (1) to assist individuals in their social networks with needs that are difficult for professionals to address; (2) to negotiate with professionals for support from the health system; and (3) to mobilize the resources of associations in their community to sustain support from the health system. 相似文献
44.
Eng SB Werker DH King AS Marion SA Bell A Issac-Renton JL Irwin GS Bowie WR 《Emerging infectious diseases》1999,5(6):815-819
We used computer-generated dot maps to examine the spatial distribution of 94 Toxoplasma gondii infections associated with an outbreak in British Columbia, Canada. The incidence among patients served by one water distribution system was 3.52 times that of patients served by other sources. Acute T. gondii infection among 3, 812 pregnant women was associated with the incriminated distribution system. 相似文献
45.
Keeley R Atagi T Sabelman E Padilla J Kadlcik P Agras J Eng L Wiedman TW Nguyen K Sudekum A Rosen J 《Restorative neurology and neuroscience》1993,5(5):353-366
Current methods of peripheral nerve repair are to directly suture cut nerve stumps, or to bridge large gaps with an autograft repair. Autograft-associated problems include donor site morbidity and limited supply. Many of the present limitations of nerve repair might be overcome by expanding the patients own Schwann cells in vitro, then combining the cells with other neuro-tropic and -trophic materials into an Artificial Nerve Graft (ANG) for bridging a nerve gap. In this 4.5 month experiment, a rat peroneal nerve model with a 10 mm gap was used to evaluate the effect of live Schwann cells on peripheral nerve regeneration. Nerve gaps were repaired with cellular ANGs containing live Schwann cell, dead Schwann cell, or mixed fibroblast/Schwann cell populations suspended in a collagen I matrix, and with sutured autografts or ANGs containing just collagen or medium. Regenerated nerves were evaluated by walking track analysis, qualitative and quantitative histology, and electrophysiology. Overall, the autograft was the best repair method, while the ANG containing live Schwann cells was statistically superior to other ANG repair methods. This study demonstrates that an ANG containing cultured syngeneic Schwann cells improves functional, histological, and electrophysiological parameters of peripheral nerve regeneration. 相似文献
46.
Charles N. Pegram Lawrence F. Eng Carol J. Wikstrand Rodney D. McComb Yueng-Ling Lee Darell D. Bigner 《Molecular and chemical neuropathology / sponsored by the International Society for Neurochemistry and the World Federation of Neurology and research groups on neurochemistry and cerebrospinal fluid》1983,3(2):119-138
The highly reproducible histochemical localization of glial fibrillary acidic protein (GFAP)? qualifies it as an important marker of astrocytes in both research and clinical applications. The primary objective of this study was to produce monoclonal antibodies having the advantage of invariant specificity, affinity, and titer to GFAP-specific epitopes of wide species distribution. We report here the characterization of four monoclonal antibodies that recognize the same or spatially close epitopes specific to GFAP. The epitope(s) detected has been phylogenetically conserved; human, bovine, ovine, canine, porcine, rabbit, guinea pig, rat, murine, and chicken brain homogenates all specifically absorb monoclonal antibody activity. Of importance to the routine application of these new anti-GFAP monoclonal antibodies is the demonstration here of the stability of the antigen-antibody interaction in normal, reactive, and neoplastic astrocytes of both rat and human origing following various methods of fixation. 相似文献
47.
Natham B 《Obesity surgery》1992,2(3):217-218
Medieval medical views on obesity are presented from Avicenna's Canon of Medicine. Health risks associated with obesity were appreciated, including respiratory and cardiovascular problems, infertility and
even sudden death. 相似文献
48.
Brachial plexus catheter reservoir for the treatment of upper-extremity cancer pain: technical case report 总被引:4,自引:0,他引:4
OBJECTIVE AND IMPORTANCE: Infiltration of the brachial plexus with anesthetics can provide relief of upper-extremity pain from invasive cancer. Because the analgesia is short-lived, however, repeated invasive treatments are necessary. We describe the implantation of a catheter reservoir system, in which anesthetic injections through a subcutaneous port resulted in anesthetic infiltration of the brachial plexus. CLINICAL PRESENTATION: A 47-year-old Hispanic man with squamous cell carcinoma of the larynx had undergone surgical resection, radiation treatment, and chemotherapy. Two years later, he had locally recurrent disease involving the brachial plexus, neck, and chest wall. The patient's pain was minimally responsive to narcotics, which also caused severe nausea and anorexia. TECHNIQUE: The brachial plexus was localized percutaneously with a needle electrode stimulator. Contrast injection under fluoroscopy confirmed entry into the plexus sheath. With use of the Seldinger technique, two Silastic catheters were placed within the brachial plexus and attached with a "Y" connector to a reservoir. The patient experienced complete relief of upper-extremity pain after a test injection with xylocaine. Thereafter, serial injections of bupivacaine with triamcinolone at 1-week intervals provided complete pain relief. After the treatments were initiated, the patient reported improved sleep and an improvement in his quality of life. CONCLUSION: A catheter reservoir system for brachial plexus analgesia can provide safe and effective analgesia for upper-extremity pain. This technique negates the need for repeated invasive procedures and avoids the complications of neurolysis. 相似文献
49.
50.