全文获取类型
收费全文 | 33199篇 |
免费 | 2264篇 |
国内免费 | 111篇 |
专业分类
耳鼻咽喉 | 280篇 |
儿科学 | 1326篇 |
妇产科学 | 990篇 |
基础医学 | 4504篇 |
口腔科学 | 414篇 |
临床医学 | 4243篇 |
内科学 | 6396篇 |
皮肤病学 | 648篇 |
神经病学 | 3554篇 |
特种医学 | 734篇 |
外科学 | 3220篇 |
综合类 | 347篇 |
一般理论 | 32篇 |
预防医学 | 3875篇 |
眼科学 | 560篇 |
药学 | 1944篇 |
中国医学 | 56篇 |
肿瘤学 | 2451篇 |
出版年
2024年 | 39篇 |
2023年 | 253篇 |
2022年 | 466篇 |
2021年 | 931篇 |
2020年 | 584篇 |
2019年 | 970篇 |
2018年 | 1037篇 |
2017年 | 728篇 |
2016年 | 836篇 |
2015年 | 871篇 |
2014年 | 1232篇 |
2013年 | 1809篇 |
2012年 | 2686篇 |
2011年 | 2745篇 |
2010年 | 1520篇 |
2009年 | 1258篇 |
2008年 | 2182篇 |
2007年 | 2364篇 |
2006年 | 2287篇 |
2005年 | 2162篇 |
2004年 | 1928篇 |
2003年 | 1786篇 |
2002年 | 1717篇 |
2001年 | 249篇 |
2000年 | 191篇 |
1999年 | 230篇 |
1998年 | 324篇 |
1997年 | 287篇 |
1996年 | 224篇 |
1995年 | 192篇 |
1994年 | 154篇 |
1993年 | 189篇 |
1992年 | 118篇 |
1991年 | 97篇 |
1990年 | 75篇 |
1989年 | 69篇 |
1988年 | 85篇 |
1987年 | 45篇 |
1986年 | 52篇 |
1985年 | 47篇 |
1984年 | 57篇 |
1983年 | 53篇 |
1982年 | 55篇 |
1981年 | 48篇 |
1980年 | 55篇 |
1979年 | 38篇 |
1978年 | 37篇 |
1977年 | 28篇 |
1975年 | 18篇 |
1973年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
82.
83.
Bryce A. Kiberd Tammy Keough-Ryan Catherine M. Clase 《American journal of transplantation》2003,3(5):619-625
American Society of Transplantation guidelines recommend screening renal transplant recipients for breast, colorectal and prostate cancer. However there is a lack of evidence to support this practice. Computer simulation modeling was used to estimate the years of life lost as a result of these cancers in 50-year-old renal transplant recipients and subjects in the general population. Renal transplant recipients lost fewer years of life to cancer than people in the general population largely because of reduced life expectancy. In nondiabetic transplant recipients, loss of life as a result of these cancers was comparable with that in the general population only under assumptions of increased cancer incidence and cancer-specific mortality risks. Even with two-fold higher cancer incidence and disease-specific mortality risks, diabetic transplant recipients lost considerably fewer life years to cancer than those in the general population. Recommended cancer screening for the general population may not yield the expected benefits in the average renal transplant recipient but the benefits will be considerably higher than for patients on dialysis. Transplanted patients at above-average cancer risk in good health may achieve the benefits of screening that are seen in the general population. 相似文献
84.
Gérard Brunel Edmond Benqué Frédéric Elharar Catherine Sansac Jean François Duffort Pierre Barthet Eric Baysse Neal Miller 《Clinical oral implants research》1998,9(5):303-312
The aim of the present study was to evaluate the combined application of different bioabsorbable materials for healing of residual peri‐implant defects after placement of non‐submerged implants into fresh extraction sockets. Second and third mandibular premolars were extracted from 10 Beagle dogs, the coronal part of the distal sockets were surgically enlarged and this was followed by immediate placement of specially designed hollow‐screw non‐submerged dental implants. For each animal, the coronal peri‐implant defects were further treated with one of the 4 following procedures: 1) no treatment, control site: 2) grafting with porous hydroxyapatite (HA); 3) collagen membrane tightly secured around the implant and over the defect and 4) grafting with HA covered with a collagen membrane. After 16 weeks of healing, specimens were removed from the mandibule and prepared for a histomorphometric evaluation. The bone-to-implant contact length (BIC) was measured and compared amongst the different treatment modalities. In the defect area, the irregular bone regeneration was similar between all the treatment procedures ( P >0.10). In the sites covered with a collagen membrane alone, the total BIC (47%) was greater than in control sites (28.7%. P <0.05) or sites grafted with HA (22.2%, P <0.02). Total BIC in sites treated with the HA‐membrane combination (43%) was only significantly different from sites treated with HA ( P <0.10). It is concluded that the use of bioabsorbable materials results in a limited increase of osseointegration when used in conjunction with immediate placement of non-submerged implants, although the principle of the one stage surgical approach can be maintained. 相似文献
85.
Dr. Hershel Jick M.D. Dr. Laura E. Derby D.Sc. Dr. Victor Gurewich M.D. Mr. Catherine Vasilakis M.P.H. 《Pharmacotherapy》1996,16(3):321-326
We conducted a case-control study based on computer-recorded information accrued in the United Kingdom General Practice Research Database to assess and compare the relation between different antihypertensive drug therapies and myocardial infarction in patients with no known clinical or laboratory risk factors for myocardial infarction other than hypertension. Cases were treated hypertensive patients with no other known risk factors who developed a first acute myocardial infarction between January 1, 1993, and October 31, 1994. They were ascertained from a review of the clinical record together with a questionnaire filled out by the attending general practitioner. Controls were matched to each case for age, sex, general practice, and index date. Antihypertensive therapy was derived from the computerized patient record. The study consisted of 210 cases and 793 controls. Compared with users of β-blockers alone, the adjusted relative risk (RR) estimates for all other treatment regimens were close to 1.0. A comparison of users of calcium channel blockers alone with users of β-blockers alone yielded a RR estimate of 0.9 (95% CI 0.5, 1.7). We conclude that the risk of acute myocardial infarction in otherwise healthy, treated hypertensive patients is not materially associated with the particular drug they receive. 相似文献
86.
The addition of normal mouse serum (NMS) to mouse bone marrow cell cultures was found to stimulate the growth of late erythroid precursors (CFU-E). The stimulating activity was called Erythropoietic Stimulating Cofactor (ESCF) (Blanchet et al 1984). In this article, we report that CFU-Es from foetal liver are not sensitive to serum addition, in contrast to CFU-Es from bone marrow or spleen taken from the same foetuses. When foetal liver cells were co-cultured with irradiated adult bone marrow cells, addition of NMS stimulated the foetal liver CFU-Es, suggesting that ESCF acts via some accessory cells not present (or in too low a frequency) among foetal liver cells. Moreover, NMS should be added at onset of adult bone marrow cell culture to be fully stimulatory. In addition, a very large increase (by a factor of 5 to 7) was observed for CFU-Es from spleen and bone marrow from 6- to 20-d-old newborn mice. This high sensitivity was correlated with a post-natal anaemia. We propose the existence of two different CFU-E population, one stimulated by the accessory cells, the other not, the proportion of which could be modified in response to anaemia. 相似文献
87.
88.
Julie D Rippeth Robert K Heaton Catherine L Carey Thomas D Marcotte David J Moore Raul Gonzalez Tanya Wolfson Igor Grant 《Journal of the International Neuropsychological Society》2004,10(1):1-14
Both HIV infection and methamphetamine dependence can be associated with brain dysfunction. Little is known, however, about the cognitive effects of concurrent HIV infection and methamphetamine dependence. The present study included 200 participants in 4 groups: HIV infected/methamphetamine dependent (HIV+/METH+), HIV negative/methamphetamine dependent (HIV-/METH+), HIV infected/methamphetamine nondependent (HIV+/METH-), and HIV negative/methamphetamine nondependent (HIV-/METH-). Study groups were comparable for age, education, and ethnicity, although the HIV-/METH- group had significantly more females. A comprehensive, demographically corrected neuropsychological battery was administered yielding a global performance score and scores for seven neurobehavioral domains. Rates of neuropsychological impairment were determined by cutoff scores derived from performances of a separate control group and validated with larger samples of HIV+ and HIV- participants from an independent cohort. Rates of global neuropsychological impairment were higher in the HIV+/METH+ (58%), HIV-/METH+ (40%) and HIV+/METH- (38%) groups compared to the HIV-/METH- (18%) group. Nonparametric analyses revealed a significant monotonic trend for global cognitive status across groups, with least impairment in the control group and highest prevalence of impairment in the group with concurrent HIV infection and methamphetamine dependence. The results indicate that HIV infection and methamphetamine dependence are each associated with neuropsychological deficits, and suggest that these factors in combination are associated with additive deleterious cognitive effects. This additivity may reflect common pathways to neural injury involving both cytotoxic and apoptotic mechanisms. 相似文献
89.
Janice Matthews-Greer Dorothy Rivette Rosalina Reyes Catherine F Vanderloos Elba A Turbat-Herrera 《Clinical laboratory science》2004,17(1):8-11
OBJECTIVE: Thirteen specific types of human papillomavirus (HPV), classified as high-risk for the development of cervical cancer, have been reported in 99.7% of all cervical cancers. For this reason, and because of the reported lack of sensitivity of the Papanicolaou (Pap) smear for detecting HPV, some experts believe that the use of papillomavirus DNA testing may replace cytology for routine gynecological screening. Our goal was to validate a commercial assay, the Digene Hybrid Capture-2 for the detection of human papillomavirus by comparing the results to cytological detection of cervical abnormalities. DESIGN: Cytology results of concurrent liquid-based Papanicolaou smears were compared to the Hybrid Capture-2 results. Correlation was assessed and discordant cytology results were reviewed. SETTING: Louisiana State University Health Sciences Center at Shreveport, Department of Pathology, HPV Diagnostic Laboratory. PATIENTS: All liquid cytology specimens submitted for HPV testing between November 1, 2000 and April 1, 2001. RESULTS: Of the 291 cases tested by Hybrid Capture-2, 12% and 28% were positive with the low-risk and high-risk probes, respectively, and 265 had concurrent cytology results. Fourteen specimens testing positive only with the low-risk probe were not included in this comparison. Thus, the results for 251 of the 291 (86%) specimens tested for human papillomavirus DNA were compared to the original cytology report. Overall concordance between Hybrid Capture-2 and the original smear cytology result was 78%. Slide review reduced the number of discordant specimens from 22% to 12%. CONCLUSION: Based upon these data, we find the HPV assay to be useful as a routine screen for Human papillomavirus. 相似文献
90.
Jamie A Koufman Catherine J Rees William D Frazier Lauren A Kilpatrick S Carter Wright Stacey L Halum Gregory N Postma 《Otolaryngology--head and neck surgery》2007,137(1):146-151
BACKGROUND: Unsedated office-based laser surgery (UOLS) of the larynx and trachea has significantly improved the treatment options for patients with laryngotracheal pathology including recurrent respiratory papillomas, granulomas, leukoplakia, and polypoid degeneration. UOLS delivered by flexible endoscopes has dramatically impacted office-based surgery by reducing the time, costs, and morbidity of surgery. OBJECTIVES: To review our experience with 443 laryngotracheal cases treated by UOLS. METHODS: The laser logbooks at the Center for Voice and Swallowing Disorders were reviewed for UOLS, and the medical and laryngological histories were detailed, as were the treatment modalities, frequencies, and complications. RESULTS: Of the 443 cases, 406 were performed with the pulsed-dye laser, 10 with the carbon-dioxide laser, and 27 with the thulium: yttrium-aluminum-garnet laser. There were no significant complications in this series. A review of indications and wavelength selection criteria is presented. CONCLUSION: Unsedated, office-based, upper aerodigestive tract laser surgery appears to be a safe and effective treatment option for many patients with laryngotracheal pathology. 相似文献