全文获取类型
收费全文 | 4336篇 |
免费 | 419篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 152篇 |
妇产科学 | 87篇 |
基础医学 | 706篇 |
口腔科学 | 80篇 |
临床医学 | 477篇 |
内科学 | 742篇 |
皮肤病学 | 90篇 |
神经病学 | 290篇 |
特种医学 | 353篇 |
外科学 | 557篇 |
综合类 | 116篇 |
一般理论 | 3篇 |
预防医学 | 348篇 |
眼科学 | 134篇 |
药学 | 394篇 |
中国医学 | 5篇 |
肿瘤学 | 200篇 |
出版年
2021年 | 56篇 |
2020年 | 32篇 |
2019年 | 58篇 |
2018年 | 76篇 |
2017年 | 54篇 |
2016年 | 51篇 |
2015年 | 81篇 |
2014年 | 100篇 |
2013年 | 133篇 |
2012年 | 198篇 |
2011年 | 199篇 |
2010年 | 127篇 |
2009年 | 116篇 |
2008年 | 170篇 |
2007年 | 186篇 |
2006年 | 156篇 |
2005年 | 152篇 |
2004年 | 166篇 |
2003年 | 142篇 |
2002年 | 133篇 |
2001年 | 135篇 |
2000年 | 121篇 |
1999年 | 119篇 |
1998年 | 109篇 |
1997年 | 99篇 |
1996年 | 72篇 |
1995年 | 73篇 |
1994年 | 69篇 |
1993年 | 55篇 |
1992年 | 107篇 |
1991年 | 98篇 |
1990年 | 89篇 |
1989年 | 90篇 |
1988年 | 104篇 |
1987年 | 104篇 |
1986年 | 95篇 |
1985年 | 71篇 |
1984年 | 64篇 |
1983年 | 56篇 |
1982年 | 40篇 |
1981年 | 36篇 |
1979年 | 54篇 |
1978年 | 44篇 |
1977年 | 36篇 |
1975年 | 37篇 |
1973年 | 30篇 |
1972年 | 51篇 |
1971年 | 40篇 |
1970年 | 29篇 |
1969年 | 30篇 |
排序方式: 共有4766条查询结果,搜索用时 15 毫秒
1.
2.
Clint R. Bellenger John B. Arnold Jonathan D. Buckley Dominic Thewlis Joel T. Fuller 《Journal of Science and Medicine in Sport》2019,22(3):294-299
Objectives
To investigate whether functional overreaching affects locomotor system behaviour when running at fixed relative intensities and if any effects were associated with changes in running performance.Design
Prospective intervention study.Methods
Ten trained male runners completed three training blocks in a fixed order. Training consisted of one week of light training (baseline), two weeks of heavy training designed to induce functional overreaching, and ten days of light taper training designed to allow athletes to recover from, and adapt to, the heavy training. Locomotor behaviour, 5-km time trial performance, and subjective reports of training status (Daily Analysis of Life Demands for Athletes (DALDA) questionnaire) were assessed at the completion of each training block. Locomotor behaviour was assessed using detrended fluctuation analysis of stride intervals during running at speeds corresponding to 65% and 85% of maximum heart rate (HRmax) at baseline.Results
Time trial performance (effect size ±95% confidence interval (ES): 0.16 ± 0.06; p < 0.001), locomotor behaviour at 65% HRmax (ES: ?1.12 ± 0.95; p = 0.026), and DALDA (ES: 2.55 ± 0.80; p < 0.001) were all detrimentally affected by the heavy training. Time trial performance improved relative to baseline after the taper (ES: ?0.16 ± 0.10; p = 0.003) but locomotor behaviour at 65% HRmax (ES: ?1.18 ± 1.17; p = 0.048) and DALDA (ES: 0.92 ± 0.90; p = 0.045) remained impaired.Conclusions
Locomotor behaviour during running at 65% HRmax was impaired by functional overreaching and remained impaired after a 10-day taper, despite improved running performance. Locomotor changes may increase injury risk and should be considered within athlete monitoring programs independently of performance changes. 相似文献3.
Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography 总被引:2,自引:0,他引:2
The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study. 相似文献
4.
Predicting failure in polytetrafluoroethylene vascular access grafts for hemodialysis: a pilot study
C R Shackleton D C Taylor A R Buckley V A Rowley P L Cooperberg P D Fry 《Canadian journal of surgery》1987,30(6):442-444
In order to determine if serial, noninvasive evaluation of polytetrafluoroethylene (PTFE) vascular access grafts could identify a subgroup of patients at risk for thrombosis, the authors studied flow characteristics, using duplex ultrasonic scanning, in 18 hemodialysis patients with forearm loop grafts. On average, five examinations were performed per patient over the 10-month study period. Seven episodes of thrombosis occurred in six patients. The mean Doppler flow in grafts that subsequently thrombosed was significantly lower than in those that did not (544 +/- 218 ml/min versus 843 +/- 391 ml/min, p less than 0.001). The interval from last examination to thrombosis ranged from 13 to 58 days. At a defined cut-off flow of 450 ml/min, this test yielded a sensitivity of 83% and a specificity of 75% for episodes of thrombosis occurring within 2 to 6 weeks. The authors conclude that episodes of thrombosis in PTFE arm loop grafts are usually preceded by significantly lower Doppler-measured flow than grafts that do not thrombose and that it may be possible, by this means, to identify grafts at risk. 相似文献
5.
6.
Sarah J Buckley 《British medical journal》2005,331(7518):698-699
7.
D H Russell N E Zorn A R Buckley P D Crowe M D Sauro E M Hadden R V Farese H E Laird 《European journal of pharmacology》1990,188(2-3):139-152
Prolactin (PRL) and other trophic factors rapidly activate a nuclear pool(s) of protein kinase C (nPKC) in purified splenocyte nuclei. The PRL also enhanced [2-3H]glycerol incorporation into nuclear mono- and triacylglycerol. An assay was devised which not only probed the ability of the hormone to activate protein kinase C (PKC) but also demonstrated the presence of nuclear substrates. Using this methodology, a biphasic concentration-response curve to PRL was observed. Heterologous species of PRL and various growth factors also activated nPKC. The PRL-induced nPKC stimulation was antagonized by various immunomodulators, G protein-coupling inhibitors, PKC inhibitors, a calmodulin inhibitor, and a peripheral benzodiazepine agonist and antagonist. A monoclonal antibody to PKC, anti-rat PRL antiserum and a monoclonal anti-rat PRL receptor antibody antagonized PRL-induced PKC-dependent nuclear phosphorylation, further implicating nPKC and a PRL receptor-mediated activation process. Nuclear PKC may be a major target for trophic regulation in response to both positive and negative growth signals. 相似文献
8.
9.
With estimates as high as 1.8 million individuals infected with human immunodeficiency virus (HIV) in the United States, the majority asymptomatic, it is crucial that all physicians routinely use adequate disinfection procedures for medical instruments. The protosigmoidoscopic disinfection procedures used by US family physicians were evaluated for adequacy in inactivating HIV. Sixty-seven percent of 1,585 randomly selected American Academy of Family Physicians members completed a mail survey regarding these procedures. Comparing procedures used with those recommended by the Centers for Disease Control or documented to inactivate HIV, 32.4 percent were judged to be appropriate procedures; 54.4 percent of the procedures were not tested or recommended; and 13.2 percent used appropriate solutions but at inadequate concentrations or exposure times. Therefore, a substantial proportion of US family physicians performing endoscopic procedures use disinfection procedures that may not inactivate HIV. The ever-increasing prevalence of HIV demands that standardized adequate disinfection procedures be implemented by all physicians to prevent the potential nosocomial spread of HIV. 相似文献
10.
Paediatric dacryocystorhinostomy 总被引:1,自引:0,他引:1
KN Hakin FRCS FRCOphth TJ Sullivan FRACO FRACS A Sharma FCOphth † RAN Welham FRCS FCOphth † 《Clinical & experimental ophthalmology》1994,22(4):231-235
Of 258 cases of dacryocystorhinostomy performed on children in the period September 1981 to September 1991, 130 were for simple, unresolved congenital nasolacrimal duct obstruction. Other indications for surgery included punctal agenesis, lacrimal fistula, post-traumatic and post-inflammatory canalicular obstruction. Of 177 children without canalicular pathology, 171 (96%) were relieved of symptoms with one operation, without canalicular intubation. Of 81 cases with canalicular disease, 55 of 70 (79%) who underwent DCR plus canalicular intubation, and 10 of 11 who underwent DCR plus Lester-Jones tube, were substantially improved with one operation. No child required peroperative or postoperative blood transfusion. Dacryocystorhinostomy in childhood, in experienced surgical hands, is a safe procedure, achieving relief of symptoms in most cases, particularly in the absence of canalicular disease. 相似文献