全文获取类型
收费全文 | 668篇 |
免费 | 36篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 28篇 |
儿科学 | 22篇 |
妇产科学 | 3篇 |
基础医学 | 37篇 |
口腔科学 | 14篇 |
临床医学 | 79篇 |
内科学 | 104篇 |
皮肤病学 | 5篇 |
神经病学 | 17篇 |
特种医学 | 287篇 |
外科学 | 26篇 |
综合类 | 42篇 |
预防医学 | 10篇 |
眼科学 | 6篇 |
药学 | 11篇 |
1篇 | |
肿瘤学 | 25篇 |
出版年
2021年 | 5篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 2篇 |
2012年 | 10篇 |
2011年 | 12篇 |
2010年 | 9篇 |
2009年 | 10篇 |
2008年 | 2篇 |
2007年 | 17篇 |
2006年 | 15篇 |
2005年 | 12篇 |
2004年 | 9篇 |
2003年 | 15篇 |
2002年 | 10篇 |
2001年 | 9篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 25篇 |
1997年 | 35篇 |
1996年 | 24篇 |
1995年 | 35篇 |
1994年 | 39篇 |
1993年 | 38篇 |
1992年 | 23篇 |
1991年 | 16篇 |
1990年 | 29篇 |
1989年 | 30篇 |
1988年 | 37篇 |
1987年 | 49篇 |
1986年 | 34篇 |
1985年 | 25篇 |
1984年 | 9篇 |
1983年 | 16篇 |
1982年 | 8篇 |
1981年 | 13篇 |
1980年 | 12篇 |
1979年 | 2篇 |
1978年 | 7篇 |
1977年 | 8篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1974年 | 9篇 |
1972年 | 3篇 |
1966年 | 2篇 |
1938年 | 1篇 |
排序方式: 共有717条查询结果,搜索用时 15 毫秒
41.
The feasibility of in vitro interleukin 2 (IL-2) activation and expansion of mononuclear cells (MNCs) derived from adult patients with acute myelogenous leukemia (ANLL) was studied. Patients' natural killer (NK) and lymphokine-activated killer (LAK) cell activity was compared with that of normal donors in terms of: (a) cytolytic activity (four- hour 51Cr release assay) against an NK-sensitive target (K562), NK- resistant targets (Raji/Daudi), and fresh/cryopreserved autologous and allogeneic leukemic blasts; (b) proliferation and expansion in culture with 1,000 U/mL recombinant IL 2 (rIL 2); and (c) the cell surface phenotype of the cultured cells. In 21 of 24 patients with active disease (AP) MNCs derived from the peripheral blood (PBL) or bone marrow (BM) could be cultured and expanded in the presence of rIL 2. These cultures initially contained between 30% and 50% blasts, and during 2 to 4 weeks of culture destruction of blasts and enrichment of up to 60% in cells with the morphology of large granular lymphocytes (LGLs) was observed. Expansion in culture varied between two- and 100- fold. MNCs from all patients in remission (RP) could be activated by rIL 2 and expanded up to 30-fold after 1 to 3 weeks in culture. NK activity of fresh PBLs from AP was significantly lower than in normal controls, whereas NK activity of RP was within the normal range. High levels of postactivation NK and LAK activity on K562/Raji/Daudi and on fresh/cryopreserved leukemic blasts was generated in approximately 50% of cases of AP and in most RP. Cell surface phenotype studies showed that cultured cells derived from ANLL patients were significantly enriched (up to 40%) in NKH-1 (Leu 19) positive cells, with RP LAK cells also expressing a high proportion of CD16 positive cells (up to 40%). This study has shown that it is feasible to activate and significantly expand killer cells derived from active disease and remission ANLL patients during 1 to 3 weeks culture with IL 2 with good maintenance of cytolytic activity. Both initial NK activity and LAK generation was optimal in remission patients. Based on data from this study, a clinical protocol has been developed for treatment of early relapse ANLL patients with LAK cells cultured for 1 to 3 weeks and systemic IL 2. 相似文献
42.
We report the successful long-term engraftment of normal male donor bone marrow (BM) transfused into noncytoablated female mice, challenging the assumption that "niches" need to be created for marrow to engraft. We have used chromosomal banding and Southern blot analysis to identify transplanted male marrow cells, and shown the long-term stability of the chimeric marrows. Balb/C, BDF1, or CBA-J female hosts (no irradiation) received for 5 consecutive days 40 x 10(6) male cells (per day) of the same strain, and repopulation patterns were observed. Parallel studies were performed using tibia/femur equivalents of normal marrow or marrow from Balb/C mice pretreated 6 days previously with 150 mg/kg 5-fluorouracil (5-FU). Chromosome banding techniques showed that 5% to 46% of marrow cells were male 3 to 9 months posttransplant with normal donor marrow. Southern blot analysis, using the pY2 probe, showed continued engraftment at 21 to 25 months posttransplant, ranging from 15% to 42% male engrafted cells in marrow. Normal donor male marrow engrafted significantly better than 5-FU-pretreated male marrow as shown 1 to 12 months posttransplant in non-cytoablated female recipients. Percentages of male engrafted cells in BM ranged from 23% to 78% for recipients of normal donor marrow and from 0.1% to 39% for recipients of 5-FU marrow. Mean engraftment for 6 mice receiving normal marrow was 38%, whereas that for 6 mice receiving post-5-FU marrow was 8%, as assayed 1 to 3 months posttransplant. At 10 to 12 months, mean engraftment for the normal donor group was 46%, compared with 16% for the 5-FU group. The patterns of engraftment with normal and 5-FU marrow were similar for spleen and thymus. These results show that long-term chimerism can be established after transplantation of normal donor marrow to normal nonirradiated host mice and indicate that marrow spaces do not have to be created for successful engraftment. They suggest that transplanted marrow competes equally with host marrow for marrow space. Finally, these data show that post-5-FU Balb/C male marrow is markedly inferior in the repopulation of Balb/C female host marrow, spleen, and thymus, and suggest that this population of cells may not be the ideal population for gene transfer studies. 相似文献
43.
在当前医学教育持续变革的背景中,医学教师的专业发展成为广泛关注的焦点.为了解目前美国以提高教师的教学技能为目标的教师专业发展(faculty development,FD)活动的参与率、课程设计、教学方法和评估策略等情况,美国约翰·霍普金斯大学预防、流行病学和临床研究中心采取邮件调查的方式,对美国277家教学医院进行了调查. 相似文献
44.
P Laws A Barton RB Warren 《Journal of the European Academy of Dermatology and Venereology》2010,24(11):1270-1277
Psoriasis is commonly associated with a co‐existent arthritis known as psoriatic arthritis (PsA). Although there is some treatment overlap for psoriasis and psoriatic arthritis, it is possible that dermatologists may not diagnose or treat appropriately patients who are developing psoriatic arthritis at an early stage of the disease process when joint damage may be preventable. In this article we review the criteria for diagnosis of this sero‐negative arthritis, look at the clinical indications for referral to a rheumatologist and discuss evolving treatment options relevant to both conditions. 相似文献
45.
46.
Dan J. Castro Paul H. Ward Donna J. Castro Romaine E. Saxton Robert B. Lufkin Hooshang Kangarloo Richard P. Haugland Andrew A. Zwarun Harold R. Fetterman Jacques Soudant 《The Laryngoscope》1991,101(7):1-10
A new and highly promising adjunctive modality for the diagnosis and therapy of malignancies is under development using lasers and tumor targeting dyes. To reach the eventual goal of clinical treatment, several current “fantasies and fallacies” regarding laser applications in medicine must be identified and their problems clearly outlined. A multidisciplinary scientific approach is also required to enable the clinical practicality of this laser targeting approach. Many new dyes and laser wavelengths are being tested to improve specific tumor uptake and/or retention, lower systemic toxicity, increase tissue penetration, and identify fluorochromes with synergistic properties to further enhance laser tumoricidal effects. Rapid technological advancements in magnetic resonance imaging may now provide an extremely sensitive way to detect and monitor laser-tissue effects, and allow efficient interstitial laser phototherapy of deep and sometimes inaccessible tumors. The current and future prospectives of the emerging field of laser phototherapy are described. 相似文献
47.
D J Castro R E Saxton L J Layfield H R Fetterman D J Castro P B Tartell J D Robinson S Y To E Nishimura R B Lufkin 《The Laryngoscope》1990,100(5):541-547
The rapid technological advances of magnetic resonance imaging, laser fiberoptics, and compatible probes may allow treatment of deep and sometimes surgically unreachable tumors of the head and neck with minimal morbidity through interstitial laser phototherapy. In this study, a new application of magnetic resonance imaging was developed to monitor and quantify laser-induced tissue damages. Pig skin was exposed to increased levels of argon laser (514.5 nm) at energy densities between 62.5 and 375 J/cm2 as determined by an accurate and reproducible method of dosimetry. Thermal profiles were recorded using an infrared sensor and T1- and T2-weighted magnetic resonance images were taken; afterward, biopsies were performed to quantitate the level of tissue damage. Our results demonstrate that above a certain threshold of laser energy, the magnetic resonance imaging findings are temperature dependent. Appropriate development of a scale matching laser energies, temperature profiles, T1- and T2-weighted magnetic resonance images, and histological quantitation of tissue destruction will allow us to optimize the three-dimensional control and monitoring of laser-tissue interactions. 相似文献
48.
49.
Niyazov D Borges A Ishiyama A Zaragoza E Lufkin R 《AJNR. American journal of neuroradiology》2000,21(9):1670-1672
Numerous attempts to deal surgically with otosclerosis were made before the current method of stapedectomy with stapes prosthesis was established. We report a case with unique CT findings of a patient who underwent fenestration surgery for otosclerosis in the early 1940s. Recognition of this old surgical procedure on the imaging scans may avoid misdiagnosis of labyrinthine fistulae or middle and inner ear malformations. 相似文献
50.
Tang RB Wang HY Lu HY Xiong J Li HH Qiu XH Liu HQ 《第二军医大学学报》2005,26(8):880-880
There have been extensive observations that RNA containing repetitive elements accumulates in transformed cells and tumor tissues. In the present study, we first obtained result consistent with previous observations by in situ hybridization. 相似文献