全文获取类型
收费全文 | 1920篇 |
免费 | 186篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 63篇 |
妇产科学 | 52篇 |
基础医学 | 285篇 |
口腔科学 | 25篇 |
临床医学 | 298篇 |
内科学 | 360篇 |
皮肤病学 | 16篇 |
神经病学 | 170篇 |
特种医学 | 41篇 |
外科学 | 259篇 |
综合类 | 34篇 |
预防医学 | 259篇 |
眼科学 | 11篇 |
药学 | 120篇 |
肿瘤学 | 94篇 |
出版年
2023年 | 15篇 |
2022年 | 16篇 |
2021年 | 49篇 |
2020年 | 27篇 |
2019年 | 40篇 |
2018年 | 39篇 |
2017年 | 25篇 |
2016年 | 21篇 |
2015年 | 31篇 |
2014年 | 57篇 |
2013年 | 80篇 |
2012年 | 104篇 |
2011年 | 111篇 |
2010年 | 68篇 |
2009年 | 66篇 |
2008年 | 88篇 |
2007年 | 108篇 |
2006年 | 93篇 |
2005年 | 109篇 |
2004年 | 77篇 |
2003年 | 76篇 |
2002年 | 81篇 |
2001年 | 39篇 |
2000年 | 30篇 |
1999年 | 31篇 |
1998年 | 19篇 |
1996年 | 21篇 |
1995年 | 24篇 |
1994年 | 15篇 |
1993年 | 21篇 |
1992年 | 39篇 |
1991年 | 31篇 |
1990年 | 30篇 |
1989年 | 41篇 |
1988年 | 44篇 |
1987年 | 41篇 |
1986年 | 20篇 |
1985年 | 19篇 |
1984年 | 15篇 |
1982年 | 13篇 |
1981年 | 12篇 |
1979年 | 26篇 |
1978年 | 18篇 |
1977年 | 12篇 |
1974年 | 12篇 |
1973年 | 19篇 |
1970年 | 15篇 |
1969年 | 11篇 |
1968年 | 12篇 |
1967年 | 11篇 |
排序方式: 共有2107条查询结果,搜索用时 15 毫秒
81.
Amy W. McDevitt Joshua A. Cleland Colin Strickland Paul Mintken Mary Becky Leibold Maria Borg Rebecca Altic Suzanne Snodgrass 《Journal of Physical Therapy Science》2020,32(11):760
[Purpose] Examination and treatment of the long head of the biceps tendon (LHBT) requires accurate palpation. The purpose of this study was to determine physical therapists’ reliability and ability to accurately palpate the LHBT in two arm positions with ultrasound as the gold standard. [Participants and Methods] Examiners palpated the LHBT within the intertubercular groove (ITG) of the humerus on the bilateral shoulders of 32 asymptomatic (21 female; 24.3 ± 1.9 years) participants in 2 arm positions. The magnitude of distance between a marker and the border of the ITG was compared between 2 positions using an independent t-test. Percent accuracy was calculated. [Results] Inter-rater reliability was poor (position 1, k=1.04; position 2, k=0.016). Overall accuracy rate was 45.7% (117/256). Accuracy was 49.2% (63/128) and 42.2% (54/128) for testing position 1 and position 2 respectively. Mean distance palpated from the groove was M=2.58 mm (± 6.2 mm) for position 1 and M=3.77 mm (± 6.6 mm) for position 2. Inaccurate palpation occurred medially 72.3% (47/65) and 93.2% (69/74) in position 1 and position 2 respectively. [Conclusion] Results of this study did not support one arm position being more accurate over another for LHBT palpation.Key words: Palpation, Accuracy, Long head of biceps tendon 相似文献
82.
83.
Farley BG Koshland GF 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2000,135(4):483-496
A unique feature of trunk muscles is that they can be activated to meet functional requirements for combined behaviors, including those related to posture and breathing. Trunk muscles therefore may have developed mechanisms for dealing with simultaneous inputs for different task requirements. This study was designed to test the hypothesis that a linear addition in trunk muscle activities would occur when an isometric trunk task and a pulsed expiration task was performed simultaneously. Surface electromyograms (EMG) were recorded from four trunk regions (medial and lateral back, upper and lower lateral abdomen) in sitting during the performance of the individual isometric trunk task, the individual pressure task, and the combined task (isometric trunk and pressure task). The direction of static holding for the isometric trunk task was varied between flexion and extension positions. For the pressure task subjects produced two consecutive pressure pulses (2/s) to a target oral pressure. For each muscle recording, a linear prediction was calculated from the mathematical addition of the EMG recorded from the individual trunk and pressure tasks. This linear prediction was compared to the actual muscle activity recorded during the combined task. Typically the EMG from two muscles showed linear addition, such that the relative contribution of muscle activity did not change for the combined task. This suggests that the motor commands for each task reached these motor neuron pools essentially unmodified. The other two muscles showed nonlinear combination of two EMG patterns. That is, qualitatively both EMG patterns, specific to each command, were evident in the measured EMG traces for the combined task, but quantitatively the muscle did not meet all criteria for linear addition. Linear addition may provide a simple mechanism for combining breathing-related behaviors (expiratory efforts) with other trunk behaviors (holding against gravity). This suggests that some muscles can be shared for two different voluntary tasks without changing their contribution to either component task. At the same time, nonlinear combination suggests that some muscles are shared, but their contribution to either component task may be modulated, thus avoiding the construction of a third new and unique plan. 相似文献
84.
Pennington TH 《Journal of medical microbiology》2000,49(8):677-679
85.
Asperger''s Syndrome: Evidence of an Empirical Distinction from High-Functioning Autism 总被引:14,自引:0,他引:14
Sally Ozonoff Sally J. Rogers Bruce F. Pennington 《Journal of child psychology and psychiatry, and allied disciplines》1991,32(7):1107-1122
This study compared the neuropsychological profiles of individuals with high-functioning autism (HFA) and Asperger's syndrome (AS). In comparison with matched controls, both groups were impaired on executive function tests. Only the HFA group demonstrated deficits in theory of mind and verbal memory, performing more poorly than both controls and AS subjects. These results suggest that: (1) HFA and AS are empirically distinguishable on measures independent of diagnostic criteria, and (2) impairment on theory of mind measures is not universally found among individuals with autistic spectrum conditions. The primacy of executive function and theory of mind deficits to autism is discussed. 相似文献
86.
The purpose of the study was to assess the effect of a combination regimen of herbs, vitamins, and minerals on bone mineral density (BMD) in early postmenopausal women via a 2-year, single-blind, uncontrolled, prospective trial. BMD was measured by dual energy x-ray absorptiometry (DEXA) at baseline and at 6, 12, and 24 months. Results of lumbar spine, hip, and forearm densities did not differ significantly from historical controls derived from other recent trials using a similar patient population. Bone mineral losses are reported on an annualized basis over the 2 years for the 12 women who completed the trial: spine (-1.42% per year), hip (-0.43% per year), forearm (-1.42% per year). Six women were withdrawn from the trial by the investigators because of excessive losses of bone mineral, and 1 of these women was diagnosed with hyperparathyroidism. There were no metabolic diseases to explain the losses in the remaining 5 withdrawn subjects. Four of 21 subjects experienced adverse side effects, necessitating dropping out by 3 of these women. In conclusion, the combined treatment regimen of a menopause symptom-oriented herbal blend plus a high potency vitamin/mineral was unsuccessful in protecting women against the predictable acceleration of bone mineral losses associated with early postmenopause. 相似文献
87.
Repression of stress-responsive genes by FIERY2, a novel transcriptional regulator in Arabidopsis 总被引:15,自引:0,他引:15 下载免费PDF全文
88.
Exercise-induced muscle damage is a well documented phenomenon that often follows unaccustomed and sustained metabolically demanding activities. This is a well researched, but poorly understood area, including the actual mechanisms involved in the muscle damage and repair cycle. An integrated model of muscle damage has been proposed by Armstrong and is generally accepted. A more recent aspect of exercise-induced muscle damage to be investigated is the potential of estrogen to have a protective effect against skeletal muscle damage. Estrogen has been demonstrated to have a potent antioxidant capacity that plays a protective role in cardiac muscle, but whether this antioxidant capacity has the ability to protect skeletal muscle is not fully understood. In both human and rat studies, females have been shown to have lower creatine kinase (CK) activity following both eccentric and sustained exercise compared with males. As CK is often used as an indirect marker of muscle damage, it has been suggested that female muscle may sustain less damage. However, these findings may be more indicative of the membrane stabilising effect of estrogen as some studies have shown no histological differences in male and female muscle following a damaging protocol. More recently, investigations into the potential effect of estrogen on muscle damage have explored the possible role that estrogen may play in the inflammatory response following muscle damage. In light of these studies, it may be suggested that if estrogen inhibits the vital inflammatory response process associated with the muscle damage and repair cycle, it has a negative role in restoring normal muscle function after muscle damage has occurred. This review is presented in two sections: firstly, the processes involved in the muscle damage and repair cycle are reviewed; and secondly, the possible effects that estrogen has upon these processes and muscle damage in general is discussed. The muscle damage and repair cycle is presented within a model, with particular emphasis on areas that are important to understanding the potential effect that estrogen has upon these processes. 相似文献
89.
The thymus is the major site of T cell maturation; extensive proliferation, differentiation, and apoptosis occur in this organ. During mammary tumorigenesis, there is a profound involution of the thymus associated with a severe depletion of the most abundant subset of thymocytes, CD4+8+ immature cells. Experiments to investigate the mechanism of loss of the CD4+8+ population indicated that there was no increase in the systemic levels of glucocorticoids, no loss of bone marrow precursors, and no decrease in precursor seeding of the thymus. Likewise, no enhanced emigration of thymocytes from the thymus to the periphery was observed in tumor-bearing mice. A slight increase in apoptosis was found in tumor bearers' thymi, but there was no apparent decrease in the proliferation of early thymic precursors CD4–8– cells. Importantly, severely altered levels of subpopulations of the CD4–8– precursors, consistent with an arrest in differentiation at an early stage of development, were detected. Moreover, thymic stromal cell function appeared to become impaired during tumorigenesis, possibly due to the action of tumor-derived factors. Thus, downregulation of cell-mediated immune functions occurring at late stages of the disease may be causally related to the thymic involution occurring during mammary tumorigenesis. 相似文献
90.