全文获取类型
收费全文 | 30645篇 |
免费 | 1759篇 |
国内免费 | 106篇 |
专业分类
耳鼻咽喉 | 279篇 |
儿科学 | 751篇 |
妇产科学 | 666篇 |
基础医学 | 3815篇 |
口腔科学 | 926篇 |
临床医学 | 3192篇 |
内科学 | 6083篇 |
皮肤病学 | 397篇 |
神经病学 | 2938篇 |
特种医学 | 1210篇 |
外科学 | 3439篇 |
综合类 | 312篇 |
一般理论 | 31篇 |
预防医学 | 3030篇 |
眼科学 | 750篇 |
药学 | 2499篇 |
中国医学 | 44篇 |
肿瘤学 | 2148篇 |
出版年
2023年 | 109篇 |
2022年 | 165篇 |
2021年 | 394篇 |
2020年 | 270篇 |
2019年 | 459篇 |
2018年 | 518篇 |
2017年 | 413篇 |
2016年 | 433篇 |
2015年 | 529篇 |
2014年 | 826篇 |
2013年 | 1367篇 |
2012年 | 1971篇 |
2011年 | 2112篇 |
2010年 | 1164篇 |
2009年 | 1189篇 |
2008年 | 2045篇 |
2007年 | 2274篇 |
2006年 | 2271篇 |
2005年 | 2171篇 |
2004年 | 2148篇 |
2003年 | 2034篇 |
2002年 | 1989篇 |
2001年 | 288篇 |
2000年 | 184篇 |
1999年 | 306篇 |
1998年 | 445篇 |
1997年 | 365篇 |
1996年 | 343篇 |
1995年 | 297篇 |
1994年 | 279篇 |
1993年 | 263篇 |
1992年 | 153篇 |
1991年 | 177篇 |
1990年 | 143篇 |
1989年 | 136篇 |
1988年 | 124篇 |
1987年 | 127篇 |
1986年 | 107篇 |
1985年 | 156篇 |
1984年 | 211篇 |
1983年 | 159篇 |
1982年 | 242篇 |
1981年 | 244篇 |
1980年 | 232篇 |
1979年 | 108篇 |
1978年 | 105篇 |
1977年 | 106篇 |
1976年 | 81篇 |
1975年 | 70篇 |
1974年 | 63篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Suman W Rathbun Thomas L Whitsett Gary E Raskob 《Blood coagulation & fibrinolysis》2007,18(8):795-800
The objective of this study was to test the safety of withholding anticoagulant treatment and additional call-back diagnostic testing with ultrasound in patients who have a negative D-dimer at presentation. Patients with signs and symptoms of deep-vein thrombosis who presented to the emergency department after regular hours and on weekends underwent D-dimer testing using the STA-Liatest D-di. In patients with negative D-dimer results, heparin therapy was withheld, and no further diagnostic testing for deep-vein thrombosis was done as part of the initial evaluation. Patients with positive D-dimer results underwent compression ultrasonography. The primary outcome measure was a diagnosis of new symptomatic venous thromboembolism confirmed by diagnostic testing during the 3-month follow-up period. Of the 260 eligible patients, 81 (31%) had a negative D-dimer and 179 (69%) had a positive D-dimer. No patient with a negative D-dimer at presentation had confirmed venous thromboembolism at 3-month follow-up. Three patients died: one by intracranial hemorrhage secondary to cerebrovascular accident; and two deaths of indeterminate cause almost 3 months after entry. The automated assay for D-dimer, the STA-Liatest D-di, seems to provide a simple method with high clinical utility for excluding acute first-episode deep-vein thrombosis in symptomatic patients who present to the emergency room after regular hours. 相似文献
72.
73.
The aims of this study were (1) to elicit the users' responses to four electronic head-mounted devices (Jordy, Flipperport, Maxport and NuVision) and (2) to correlate users' opinion with performance. Ten patients with early onset macular disease (EOMD) and 10 with age-related macular disease (AMD) used these electronic vision enhancement systems (EVESs) for a variety of visual tasks. A questionnaire designed in-house and a modified VF-14 were used to evaluate the responses. Following initial experience of the devices in the laboratory, every patient took home two of the four devices for 1 week each. Responses were re-evaluated after this period of home loan. No single EVES stood out as the strong preference for all aspects evaluated. In the laboratory-based appraisal, Flipperport typically received the best overall ratings and highest score for image quality and ability to magnify, but after home loan there was no significant difference between devices. Comfort of device, although important, was not predictive of rating once magnification had been taken into account. For actual performance, a threshold effect was seen whereby ratings increased as reading speed improved up to 60 words per minute. Newly diagnosed patients responded most positively to EVESs, but otherwise users' opinion could not be predicted by age, gender, diagnosis or previous CCTV experience. User feedback is essential in our quest to understand the benefits and shortcoming of EVESs. Such information should help guide both prescribing and future development of low vision devices. 相似文献
74.
Gary A Noskin Robert J Rubin Jerome J Schentag Jan Kluytmans Edwin C Hedblom Cassie Jacobson Maartje Smulders Eric Gemmen Murtuza Bharmal 《Clinical infectious diseases》2007,45(9):1132-1140
BACKGROUND: We evaluated historical trends in the Staphylococcus aureus infection rate, economic burden, and mortality in US hospitals from 1998 through 2003. METHODS: The Nationwide Inpatient Sample was used to assess trends over time of S. aureus infection during 1998-2003. Historical trends were determined for 5 strata of hospital stays, including all inpatient stays, surgical procedure stays, invasive cardiovascular surgical stays, invasive orthopedic surgical stays, and invasive neurosurgical stays. RESULTS: During the 6-year study period from 1998 through 2003, the rate of S. aureus infection increased significantly for all inpatient stays (from 0.74% to 1.0%; annual percentage change (APC), 7.1%; P=.004), surgical stays (from 0.90% to 1.3%; APC, 7.9%; P=.001), and invasive orthopedic surgical stays (from 1.2% to 1.8%; APC, 9.3%; P<.001). For invasive neurosurgical stays, the rate of S. aureus infection did not change from 1998 to 2000 but increased at an annual rate of 11.0% from 2000 to 2003 (from 1.4% to 1.8%; P=.034). The total economic burden of S. aureus infection for hospitals also increased significantly for all stay types, with the annual percentage increase ranging from 9.2% to 17.9% (P<.05 for all). In 2003, the total economic burden of S. aureus infection was estimated to be $14.5 billion for all inpatient stays and $12.3 billion for surgical patient stays. However, there were significant decreases in the risk of S. aureus-related in-hospital mortality from 1998 to 2003 for all inpatient stays (from 7.1% to 5.6%; APC, -4.6%; P=.001) and for surgical stays (from 7.1% to 5.5%; APC, -4.6%; P=.002). CONCLUSIONS: The inpatient S. aureus infection rate and economic burden of S. aureus infections for US hospitals increased substantially from 1998 to 2003, whereas the in-hospital mortality rate decreased. 相似文献
75.
John L Waddington Aiden P Corvin Gary Donohoe Colm M P O'Tuathaigh Kevin J Mitchell Michael Gill 《The Psychiatric clinics of North America》2007,30(3):365-399
This article summarizes the rationale, methods, and results of gene discovery programs in schizophrenia research and describes functional methods of investigating potential candidate genes. It focuses next on the most prominent current candidate genes and describes (1) evidence for their association with schizophrenia and research into the function of each gene; (2) investigation of the clinical phenotypes and endophenotypes associated with each gene, at the levels of psychopathologic, neurocognitive, electrophysiologic, neuroimaging, and neuropathologic findings; and (3) research into the ethologic, cognitive, social, and psychopharmacologic phenotype of mutants with targeted deletion of each gene. It examines gene-gene and gene-environment interactions. Finally, it looks at future directions for research. 相似文献
76.
Gary D. Reeder 《Transfusion》2004,44(S2):35S-39S
77.
J Martin Palomo Gary R Wolf Mark G Hans 《American journal of orthodontics and dentofacial orthopedics》2004,126(3):381-385
In 2002, the orthodontic clinic at Case Western Reserve University totally converted to digital photography. We want to share the learning curve during this transition with clinicians planning the same change. A system and a protocol were developed for this transition; they have been in use for over a year. This system allows the handling of digital cameras when there are more clinicians than cameras; it can be applied to various specialties or fields. 相似文献
78.
OBJECTIVE: Retrospectively assess the efficacy of lumbar cerebrospinal fluid (CSF) drainage placed preoperatively in skull base operations in decreasing the incidence of postoperative CSF fistula. METHODS: A retrospective review of 150 patients undergoing a posterior fossa craniotomy from 1989 to 2000 was conducted. Patients were divided into those receiving preoperative lumbar drains and those that did not. The rates of postoperative CSF leakage were compared between the two groups. Patient data were analyzed to determine if there were other comorbidities affecting the postoperative incidence of CSF leakage such as smoking, diabetes, or hypertension. RESULTS: Between 1989 and 1994, 25/72 (35%) patients with no preoperative lumbar drain had a postoperative CSF leak. From 1995 to 2000, 9/78 (12%) patients with a preoperative lumbar drain had a CSF leak. This was a 23% decreased incidence of postoperative CSF leakage and a significant decrease in the probability (p < 0.001) of CSF leakage in patients treated with a preoperative lumbar drain. The comorbidities of diabetes, smoking, or hypertension did not increase the probability of a CSF leak (p = 0.43). CONCLUSIONS: A preoperatively placed lumbar drain can significantly lower the rate of postoperative CSF leakage after skull base surgery. The drain is a well-tolerated adjunct to dural closure and helps increase surgical exposure of the posterior fossa. The comorbidities of diabetes, smoking, or hypertension do not contribute to an increased rate of CSF leakage.dagger Lyal Leibrock M.D., F.A.C.S. is Deceased. 相似文献
79.
Van Buskirk Glenn A. González Mario A. Shah Vinod P. Barnhardt Scott Barrett Colin Berge Stephen Cleary Gary Chan Keith Flynn Gordon Foster Thomas Gale Robert Garrison Raymond Gochnour Scott Gotto Amanda Govil Sharad Gray Vivian A. Hammar James Harder Samuel Hoiberg Charles Hussain Ajaz Karp Carol Llanos Hector Mantelle Juan Noonan Patrick Swanson David Zerbe Horst 《Pharmaceutical research》1997,14(7):848-852
Pharmaceutical Research - 相似文献
80.
Dodd Steven W. Havel Henry A. Kovach Paul M. Lakshminarayan Chitra Redmon Martin P. Sargeant Charlene M. Sullivan Gary R. Beals John M. 《Pharmaceutical research》1995,12(1):60-68
Mixing pharmaceutical preparations of soluble neutral regular insulin solution (NRI) and neutral protamine Hagedorn (NPH) crystalline insulin suspension leads to a reduction in the measurable amount of soluble insulin in the formulation supernatant. However in spite of the loss in soluble insulin, the time-actions of these components have been shown, in clinical trials, to be unaffected. The interaction between these different physical forms of insulin has been studied using reversed-phase HPLC, isothermal titrating calorimetry, and Doppler electrophoretic light scattering analysis. Sorbent surface and solution perturbation studies revealed that the NRI adsorbs to the surface of the NPH crystal with an equilibrium constant ranging from 104 M–1 to 107 M–!, depending on the protamine concentration, pH, ionic strength, and temperature. This adsorption behavior suggests that the binding is mediated by electrostatic interactions arising between the positively-charged NPH crystal and the negatively-charged NRI hexamer. Doppler electrophoretic light scattering results, used to probe the pH-dependent surface charge of NPH and soluble insulin hexamer, support the conclusion that electrostatic interactions mediate the adsorption process. Adsorption studies under physiological conditions indicate that the elevated temperature and ionic strength, in a subcutaneous depot, are sufficient to lead to the dissociation of the NRI/NPH complex that exists in these NPH mixture formulations. 相似文献