全文获取类型
收费全文 | 2594篇 |
免费 | 154篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 155篇 |
儿科学 | 48篇 |
妇产科学 | 21篇 |
基础医学 | 319篇 |
口腔科学 | 38篇 |
临床医学 | 374篇 |
内科学 | 402篇 |
皮肤病学 | 29篇 |
神经病学 | 221篇 |
特种医学 | 154篇 |
外科学 | 302篇 |
综合类 | 42篇 |
一般理论 | 3篇 |
预防医学 | 384篇 |
眼科学 | 16篇 |
药学 | 97篇 |
1篇 | |
肿瘤学 | 161篇 |
出版年
2021年 | 25篇 |
2019年 | 23篇 |
2018年 | 23篇 |
2017年 | 16篇 |
2016年 | 18篇 |
2015年 | 22篇 |
2014年 | 37篇 |
2013年 | 51篇 |
2012年 | 116篇 |
2011年 | 124篇 |
2010年 | 56篇 |
2009年 | 53篇 |
2008年 | 96篇 |
2007年 | 113篇 |
2006年 | 81篇 |
2005年 | 87篇 |
2004年 | 82篇 |
2003年 | 91篇 |
2002年 | 91篇 |
2001年 | 71篇 |
2000年 | 84篇 |
1999年 | 63篇 |
1998年 | 49篇 |
1997年 | 96篇 |
1996年 | 56篇 |
1995年 | 32篇 |
1994年 | 53篇 |
1993年 | 33篇 |
1992年 | 74篇 |
1991年 | 67篇 |
1990年 | 76篇 |
1989年 | 86篇 |
1988年 | 61篇 |
1987年 | 54篇 |
1986年 | 68篇 |
1985年 | 65篇 |
1984年 | 31篇 |
1983年 | 30篇 |
1982年 | 21篇 |
1981年 | 24篇 |
1980年 | 19篇 |
1979年 | 26篇 |
1978年 | 24篇 |
1977年 | 24篇 |
1976年 | 20篇 |
1975年 | 19篇 |
1974年 | 26篇 |
1973年 | 23篇 |
1972年 | 20篇 |
1967年 | 16篇 |
排序方式: 共有2767条查询结果,搜索用时 46 毫秒
31.
In a DUI offender sample, four drinking reason factors are regressed on alcohol consumption variables and frequency of drinking in seven types of locations. Drinking for "pleasure" and "opposite sex/drunkenness" reasons are associated with both quantity consumed per occasion and away-from-home locations such as automobiles, bars, and parties, suggesting high traffic accident risk. "Escapism" reasons are related to quantity consumed per occasion, but are only weakly associated with specific locations; and "sociability" reasons are associated with drinking in friends' homes, but are not related to high consumption levels. Implications for DUI countermeasures are discussed. 相似文献
32.
We analyzed amniotic fluid from 91 pregnancies (estimated gestational age range 31 to 41 weeks), using the Lumadex-FSI Fetal Lung Maturity test (Beckman Instruments), and also determining phosphatidylglycerol content, the lecithin/sphingomyelin ratio, and foam stability index by the "shake test," and compared results with newborn outcome. Five of 64 babies born within 72 h of testing developed hyaline membrane disease. Except for the lecithin/sphingomyelin ratio, the predictive value of a negative test was 100% but that of a positive test was less than 50%. Use of all four tests did not offer diagnostic advantage over the use of Lumadex-FSI alone. For the laboratory that infrequently assesses fetal lung maturity, we believe the sealed cassette format of the Lumadex-FSI will permit better quality assurance than the shake test. The Lumadex-FSI test is intended to provide a graded estimate of positive risk for hyaline membrane disease, but more data from different centers and patient populations are needed to establish reliable predictive values. 相似文献
33.
Polychlorobiphenyl (PCB) congeners,p,p′-DDE,and hexachlorobenzene in maternal and fetal cord blood from mothers in upstate New York 总被引:3,自引:0,他引:3
B. Bush J. Snow R. Koblintz 《Archives of environmental contamination and toxicology》1984,13(5):517-527
Whole blood samples were taken from 101 women (26±4 years) entering maternity facilities in upstate New York. At birth, fetal cord blood was also collected. The samples were analyzed for 74 polychlorobiphenyl (PCB) congeners,p,p-DDE, mirex, and hexachlorobenzene by glass capillary gas chromatography with electron capture detection. Maternal blood contained 3.5±1.1 ng total PCB/g whole blood and fetal cord blood contained 2.4±1.0 ng total PCB/g whole blood, which indicate that the women are less contaminated than women surveyed elsewhere in the U.S. Of the 77 compounds measured, only 20 occurred in more than 10% of the maternal samples at levels >0.01 ng/g. Mirex was not detected. Although the concentration of the majority of congeners,p,p-DDE and hexachlorobenzene correlated in maternal and fetal cord blood, 2,5,2,5-tetrachlorobiphenyl and hexachlorobenzene crossed the placenta preferentially. Apparently, the population contains vestiges of Aroclor® 1242 (the PCB mixture used in electrical equipment) and Aroclor® 1260 (the mixture used as a plasticizer).p,p- DDE was the pollutant present at highest concentration (maternal 3.8±0.8 ng/g, fetal cord 1.9±0.9 ng/g). 相似文献
34.
Grad Roland Leger Daniel Kaczorowski Janusz Schuster Tibor Adler Samara Aman Marya Archibald Douglas Beaulieu Marie-Claude Chmelicek John Cornelissen Evelyn Delleman Bethany Hadj-Mimoune Sonia Horvey Samantha Macaluso Steven Mintsioulis Stephen Murdoch Stuart Ng Brian Papineau Alain Rangwala Sohil Rousseau Mathieu Rudkin Teresa Schabort Inge Schultz Karen Snow Pamela Wong Eric Wu Pearson Brailovsky Carlos 《Advances in health sciences education : theory and practice》2021,26(3):771-783
Advances in Health Sciences Education - Spaced education is a learning strategy to improve knowledge acquisition and retention. To date, no robust evidence exists to support the utility of spaced... 相似文献
35.
36.
Hardy Christopher Fairley Christopher K. Ong Jason J. Vodstrcil Lenka A. Bradshaw Catriona S. Snow Anthony Chow Eric P. F. 《Archives of sexual behavior》2022,51(5):2497-2507
Rises in condomless anal sex among men who have sex with men (MSM) have been reported over the last decade but there is less certainty about the role that drugs, alcohol, play in this change. We examined the changes in drug and alcohol use among 22,255 MSM reporting condomless anal sex at Melbourne Sexual Health Centre in 2011–2017. There was a 7% annual increase in using drugs before and/or during condomless anal sex but a 3% annual reduction in condomless anal sex while drunk. MSM taking PrEP were more likely to report condomless anal sex with drug use (AOR: 1.21; 95%CI: 1.07–1.37) and alcohol use (AOR: 1.29; 95%CI: 1.14–1.46) compared with MSM not taking PrEP.
相似文献37.
38.
Most applications of radiofrequency (RF) catheter ablation for treatment of ventricular tachycardia (VT) have been as a treatment of last resort. The purpose of this study was to determine the efficacy and safety of RF catheter ablation as the primary treatment for symptomatic single morphology VT. Eleven of 81 patients (14%) with inducible sustained monomorphic VT underwent RF ablation as the primary treatment. One of these 11 patients had successful RF ablation of bundle branch reentry VT and was excluded from this series. The remaining 10 patients had a mean age of 58 +/- 19 years (range 20 to 73 years), were mostly men (7 of 10 patients), and all presented with documented evidence of symptomatic sustained monomorphic VT, at a mean cycle length of 340 +/- 60 milliseconds (ms) (range 250 to 430 ms). Six patients had coronary artery disease (CAD), one had surgical repair for tetralogy of Fallot, one had surgical repair of a ventricular septal defect, and two had a normal cardiac substrate. The VT origin was mapped using a combination of activation mapping, mid-diastolic potentials, pace mapping, and concealed entrainment. A mean of 5 +/- 3 (range 2 to 11) RF applications were administered to the putative VT foci. Eight of 10 (80%) clinical VTs were successfully ablated. There were no serious complications. Patients with VT originating from the left ventricle were offered implantable cardioverter-defibrillator back-up; however, only one patient accepted this option. At a mean follow-up of 12 +/- 7 months, only one patient had a possible arrhythmia recurrence. 相似文献
39.
There is an urgent need for an effective adjuvant systemic therapy for the treatment of patients with advanced head and neck cancer. This study shows that therapy based on the use of monoclonal antibodies (MAbs) is developing to a realistic option. A few years ago the first MAbs with specificity for squamous cell carcinoma of the head and neck (HNSCC) were produced, among which was MAb E48. In animal and patient studies, in which localization of radiolabelled MAb E48 was analysed qualitatively and quantitatively, it was demonstrated that a high percentage of the injected dose accumulated selectively in the tumour. These targeting properties, when exploited for delivery of toxic agents to the tumour, give MAb E48 potential for tumour therapy. Especially the application of MAb E48 in radioimmunotherapy (RIT) seems to be attractive due to the intrinsic radiosensitivity of HNSCC. Armed with 186-Rhenium, a radionuclide recently introduced in the field of RIT, MAb E48 IgG was shown to be highly capable of eradicating established HNSCC tumours in nude mice. Complete ablation of small HNSCC was observed in this animal model by a single bolus injection. In an effort to make MAb E48 less antigenic for human application a chimeric human/mouse MAb (cMAb) has been constructed by use of recombinant DNA techniques. This modification strongly improved the capacity of MAb E48 for mediating antibody-dependent cellular cytotoxicity (ADCC). When using this cMAb E48 for RIT of minimal residual disease it can be anticipated that ADCC activity may be supportive to irradiation, especially in the ablation of single disseminated cells or small cell aggregates. Extrapolating results obtained in nude mice to patients and taking into account the good targeting in patients, RIT with E48 IgG seems to have potential for the elimination of minimal residual disease. Based on this encouraging progress, preparations are being made to evaluate the efficacy of Re-186-labelled cMAb E48 as an adjuvant in a phase III study for the treatment of patients who are at high risk for developing distant metastases. 相似文献
40.
Vedhara K Nott KH Richards SM Bradbeer C Davidson EA Ong EL Snow MH 《AIDS patient care》1995,9(6):276-280
Despite uncertainty over their reliability, CD4+ cell counts are used extensively in both clinical and research settings to document progression in HIV infection. We examined, therefore, whether the performance of a simple statistical test would facilitate greater accuracy in the use of this marker. CD4+ cell count data were collected from a cohort of deceased (N = 60) and living HIV-positive gay men (N = 100). Pearson's product moment correlation coefficients were calculated for each individual in order to examine the association between CD4+ counts and time since diagnosis. Correlations of 0.7 or greater were obtained in approximately 50 percent of cases in each cohort. For these individuals, CD4+ cell counts were deemed to be a reliable indicator of rate of progression. The results suggest that the proposed technique ensures greater precision in the use of CD4+ cell counts and that the technique cna be used in individuals with either complete (deceased patients) or partial (living patients) CD4+ data. 相似文献