全文获取类型
收费全文 | 1220篇 |
免费 | 56篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 40篇 |
妇产科学 | 53篇 |
基础医学 | 145篇 |
口腔科学 | 23篇 |
临床医学 | 161篇 |
内科学 | 259篇 |
皮肤病学 | 38篇 |
神经病学 | 77篇 |
特种医学 | 106篇 |
外国民族医学 | 1篇 |
外科学 | 130篇 |
综合类 | 61篇 |
一般理论 | 4篇 |
预防医学 | 70篇 |
眼科学 | 6篇 |
药学 | 47篇 |
中国医学 | 1篇 |
肿瘤学 | 49篇 |
出版年
2022年 | 20篇 |
2021年 | 24篇 |
2020年 | 11篇 |
2019年 | 20篇 |
2018年 | 20篇 |
2017年 | 17篇 |
2016年 | 15篇 |
2015年 | 25篇 |
2014年 | 31篇 |
2013年 | 50篇 |
2012年 | 24篇 |
2011年 | 34篇 |
2010年 | 47篇 |
2009年 | 40篇 |
2008年 | 31篇 |
2007年 | 29篇 |
2006年 | 28篇 |
2005年 | 25篇 |
2004年 | 25篇 |
2003年 | 31篇 |
2002年 | 34篇 |
2001年 | 21篇 |
2000年 | 30篇 |
1999年 | 17篇 |
1998年 | 25篇 |
1997年 | 18篇 |
1996年 | 27篇 |
1995年 | 22篇 |
1994年 | 29篇 |
1993年 | 30篇 |
1992年 | 34篇 |
1991年 | 23篇 |
1990年 | 16篇 |
1989年 | 34篇 |
1988年 | 32篇 |
1987年 | 15篇 |
1986年 | 17篇 |
1985年 | 24篇 |
1983年 | 16篇 |
1982年 | 12篇 |
1981年 | 14篇 |
1980年 | 16篇 |
1979年 | 22篇 |
1978年 | 14篇 |
1977年 | 21篇 |
1976年 | 10篇 |
1975年 | 10篇 |
1973年 | 12篇 |
1969年 | 9篇 |
1957年 | 9篇 |
排序方式: 共有1277条查询结果,搜索用时 9 毫秒
91.
92.
P M Arnow L A Pottenger C B Stocking M Siegler H W DeLeeuw 《Public health reports (Washington, D.C. : 1974)》1989,104(2):121-129
Concern regarding an occupational risk of acquiring human immunodeficiency virus (HIV) infection may influence surgeons' willingness to operate. A questionnaire survey of all orthopedists in the five cities with the most cases of acquired immunodeficiency syndrome (AIDS) was conducted to assess attitudes and practices. Questionnaires were completed anonymously by 325 of 510 orthopedists. In the previous year, 43 percent had examined or operated on an HIV-infected patient, and at least 90 percent who had had an opportunity to operate on an HIV-infected patient had chosen to do so. Decisions to operate did not appear to be based on hospital requirements, perceived ethical obligations, or knowledge of HIV transmissibility. Most orthopedists (85 percent) claimed the right to order preoperative HIV testing of high-risk patients, but such testing was ordered infrequently. Although most orthopedists believed they could not be compelled to operate and that ethically they could refuse when their health was threatened, they almost always were willing to treat HIV-infected patients. 相似文献
93.
94.
L.M. VAN GELDER M.I.H. EL GAMAL G.H.J. TIELEN 《Pacing and clinical electrophysiology : PACE》1989,12(10):1640-1649
The influence of pacemaker output on the morphology of the paced QRS complex was studied from standard lead electrocardiograms in 69 patients with bipolar pacemakers. In 40 of the 69 patients (58%), there was a significant (P less than 0.001) change in electrical axis, from -75 degrees at the low output setting (2.7 V, 0.15 msec) to -67 degrees at the high output setting (8.1 V, 2.29 msec). In 30 patients, these changes were also associated with changes in the QRS morphology and in the T-wave. This phenomenon may be explained by additional stimulation from the proximal electrode at high output, thus altering the pattern of depolarization. 相似文献
95.
Upper Rate Pacing After Radiofrequency Catheter Ablation in a Minute Ventilation Rate Adaptive DDD Pacemaker 总被引:1,自引:0,他引:1
BERRY M. van GELDER FRANK A.L.E. BRACKE MAMDOUH I.H. EL GAMAL 《Pacing and clinical electrophysiology : PACE》1994,17(8):1437-1440
A 58-year-old man with an implanted minute ventilation rate adaptive DDD pacemaker underwent RF ablation of the AV junction because of symptomatic supraventricular tachyarrhythmias. Immediately after ablation, while the pacemaker was programmed in the DDDR mode, AV sequential pacing at upper rate was observed. After programming the pacing system to the DDD mode and repeated ablation, no abnormalities were observed. It was concluded that AV sequential upper rate pacing was caused by false interpretation of the RF current by the sensor measuring transthoracic impedance as an indicator for minute ventilation. 相似文献
96.
A 67-year-old male, suffering from ventricular tachycardia unresponsive to drug therapy, received a universal AV sequential pacemaker (DDD,M). Tim pacemaker was programmed in the DVI mode, pacing role 100 bpm, AV interval 250 ms. After implantation, the patient experiences two episodes of tachycardia that proved to be pacemaker tachycardia with a rate of 150 bpm. The first period was self-terminating, and the second had to be stopped by reprogramming the pulse generator. Pacemaker tachycardia could easily be provoked by instructing the patient to contract the pectoral muscle adjacent to the pulse generator. To our knowledge, this is the first report to pacemaker tachycardia provoked by myopotentials in a pulse generator programmed in the DVI mode. 相似文献
97.
Clinical use of white cell-poor blood components 总被引:1,自引:0,他引:1
EL Snyder 《Transfusion》1989,29(7):568-571
98.
Enhancement of t lymphocyte functions by Fc fragments of immunoglobulins. I. Augmentation of allogeneic mixed lymphocyte culture reactions requires I-A- or I-B-subregion differences between effector and stimulator cell populations 总被引:4,自引:1,他引:4
下载免费PDF全文
![点击此处可从《The Journal of experimental medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Fc fragments derived from human Ig were found to be capable of enhancing T cell-mediated, antigen-induced proliferative and mixed lymphocyte culture responses. Maximum enhancement occurred when suboptimal amounts of antigen or suboptimal numbers of stimulator cells were employed. Augmentation of the allogeneic mixed lymphocyte culture reaction requires an I-A and/or I-B subregion difference between effector and stimulator cell populations. Although a significant proliferative response was observed with K- or D- region differences, Fc fragments were unable to enhance the response. The T cell population acted upon by Fc fragments in the potentiation of these responses bears the Lyt-1(+)23(-) phenotype. 相似文献
99.
M Sun ; KH Chao ; LE Modahl ; G Leoung ; H Khayam-Bashi ; VL Ng ; EL Murphy 《Transfusion》1994,34(4):344-348
BACKGROUND: Asian Americans are generally underrepresented both as volunteer blood and bone marrow donors. STUDY DESIGN AND METHODS: To investigate the risk of transfusion transmission of viruses that is associated with increasing participation by Asian American donors, antibodies to human T-lymphotropic virus (HTLV), hepatitis C, and human immunodeficiency virus in Asian American volunteers recruited as potential bone marrow donors were measured. A total of 1354 Asian Americans were enrolled in the study, of whom 54 percent were Chinese, 26 percent Japanese, 9 percent Filipino, 4 percent Korean, 3 percent Indian, and 5 percent of other Asian or mixed Asian and other ethnicity. The majority of the study population was aged 20 through 49 and of high socioeconomic status, as indicated by education and income. Viral antibodies were measured with both screening enzyme-linked immunosorbent assays and supplemental testing, and polymerase chain reaction was used to resolve discrepant HTLV results. RESULTS: Confirmed seroprevalence rates for HTLV were 0.15 percent with one manufacturer's Western blot and 0.3 percent with the other; however, no sample was positive for HTLV types I or II in polymerase chain reaction. Confirmed seroprevalence to hepatitis C virus was 0.5 percent. No subject was seropositive for human immunodeficiency virus. CONCLUSION: On the basis of the moderate size and high education level of this study population, it is concluded that Asian American volunteer bone marrow donors do not pose a greater risk for transmission of HTLV type I or II, human immunodeficiency virus, or hepatitis C virus than does the average American blood donor. 相似文献
100.
L.M. VAN GELDER F.A.L.E. BRACKE M.I.H. EL GAMAL 《Pacing and clinical electrophysiology : PACE》1991,14(5):760-763
Holter recording of a patient with an implanted dual chamber rate responsive pacemaker revealed an electrocardiogram, where ventricular depolarization seemed to be initiated by the atrial stimulus. In a second patient with a VVI pacemaker, Holter recording showed delay of the pacemaker impulse that was registered after the onset of ventricular depolarization. Misalignment in one of the recorder heads of the display system was responsible for this phenomenon, which in case of dual chamber pacing could have been easily misinterpreted as pacemaker malfunction. 相似文献