首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   9744篇
  免费   730篇
  国内免费   151篇
耳鼻咽喉   85篇
儿科学   67篇
妇产科学   959篇
基础医学   1062篇
口腔科学   827篇
临床医学   1172篇
内科学   561篇
皮肤病学   101篇
神经病学   456篇
特种医学   449篇
外科学   2184篇
综合类   1059篇
预防医学   411篇
眼科学   212篇
药学   459篇
  6篇
中国医学   242篇
肿瘤学   313篇
  2024年   38篇
  2023年   160篇
  2022年   359篇
  2021年   403篇
  2020年   413篇
  2019年   417篇
  2018年   397篇
  2017年   438篇
  2016年   359篇
  2015年   333篇
  2014年   646篇
  2013年   576篇
  2012年   517篇
  2011年   571篇
  2010年   443篇
  2009年   490篇
  2008年   493篇
  2007年   423篇
  2006年   373篇
  2005年   300篇
  2004年   296篇
  2003年   225篇
  2002年   192篇
  2001年   177篇
  2000年   129篇
  1999年   144篇
  1998年   115篇
  1997年   107篇
  1996年   100篇
  1995年   109篇
  1994年   71篇
  1993年   61篇
  1992年   73篇
  1991年   59篇
  1990年   54篇
  1989年   57篇
  1988年   44篇
  1987年   59篇
  1986年   45篇
  1985年   47篇
  1984年   44篇
  1983年   36篇
  1982年   38篇
  1981年   39篇
  1980年   37篇
  1979年   22篇
  1978年   29篇
  1977年   15篇
  1976年   26篇
  1974年   9篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
101.
目的建立人体下肢肌肉功能的数学模型并编写相应的计算机软件,为人体运动过程中的下肢各肌肉力学描述及评估提供快速可靠的数据支持。方法利用现有的国人下肢肌肉附着点的三维坐标数据及其与体表骨性形态学参数的回归方程等相关研究成果,利用VisualC++6.0平台,编写下肢肌肉功能评定软件。结果软件系统可输出任意模拟姿态或实际运动过程中的下肢肌肉功能参数。结论本研究成果可从肌肉动力学层面来指导运动员的专项力量训练,提高运动成绩,也可应用于相关医学领域。  相似文献   
102.
Summary This paper highlights the many similarities between the adductor pollicis and the palmar interossei. In particular it compares their anatomy, innervation and function. It suggests that adductor pollicis should be considered as the first palmar interosseous and that this view simplifies the teaching of hand anatomy and the tests of ulnar nerve function. Further support for the view that adductor pollicis is the thenar counterpart of the second, third and fourth palmar interossei is gained from studies of the literature on hand evolution, in particular published details of fossil records and dissection of primate hands.
L'adducteur du pouce : l'interrosseux perdu
Résumé Cet article souligne les nombreuses similitudes qui existent entre le m. adducteur du pouce et le m. premier inter-osseux palmaire. Il compare en particulier l'anatomie l'innervation et la fonction de ces muscles. Le m. adducteur du pouce semble bien devoir être considéré comme le m. premier inter-osseux palmaire et ce point de vue simplifie l'enseignement de l'anatomie de la main ainsi que l'évaluation de la fonction du nerf ulnaire. Des arguments supplémentaires en faveur de l'hypothèse d'un m. adducteur du pouce qui serait la contre-partie thénarienne des second, troisème et quatrième mm. inter-osseux palmaires proviennent de l'étude de la littérature concernant la phylogénèse de la main et en particulier des résultats d'études portant sur les fossiles et les dissections de mains de primates.
  相似文献   
103.
Summary The central changes associated with a period of strength training have been investigated in a group of 32 young healthy volunteers. Subjects participated in one of three 12 week training programmes, which required different degrees of skill and coordination. Study 1 consisted of unilateral isometric training of the quadriceps with the contralateral leg acting as a control, the apparatus providing firm back support and a lap strap. In Study 2 training consisted of unilateral concentric leg-extension with back support and hand-grips. In Study 3 subjects performed bilateral leg-extension with no back support. Measurements of maximum voluntary isometric strength were made at 2–3 week intervals and a continual record was kept of the weights lifted in Studies 2 and 3. The largest increase in isometric force was seen for the trained leg in Study 1 (approximately 40%). There was no significant change in strength in the contralateral untrained leg. In Studies 2 and 3 there was a large increase in training weights (about 200%) associated with smaller increase in isometric force (15–20%). It is concluded that a large part of the improvement in the ability to lift weights was due to an increased ability to coordinate other muscle groups involved in the movement such as those used to stabilise the body. The importance of these findings for athletic training and rehabilitation is discussed.  相似文献   
104.
Summary The otolith contribution and otolith-visual interaction in eye and head stabilization were investigated in alert cats submitted to sinusoidal linear accelerations in three defined directions of space: up-down (Z motion), left-right (Y motion), and forward-back (X motion). Otolith stimulation alone was performed in total darkness with stimulus frequency varying from 0.05 to 1.39 Hz at a constant half peak-to-peak amplitude of 0.145 m (corresponding acceleration range 0.0014–1.13 g) Optokinetic stimuli were provided by sinusoidally moving a pseudorandom visual pattern in the Z and Y directions, using a similar half peak-to-peak amplitude (0.145 m, i.e., 16.1°) in the 0.025–1.39 Hz frequency domain (corresponding velocity range 2.5°–141°/s). Congruent otolith-visual interaction (costimulation, CS) was produced by moving the cat in front of the earth-stationary visual pattern, while conflicting interaction was obtained by suppressing all visual motion cues during linear motion (visual stabilization method, VS, with cat and visual pattern moving together, in phase). Electromyographic (EMG) activity of antagonist neck extensor (splenius capitis) and flexor (longus capitis) muscles as well as horizontal and vertical eye movements (electrooculography, EOG) were recorded in these different experimental conditions. Results showed that otolith-neck (ONR) and otolith-ocular (OOR) responses were produced during pure otolith stimulation with relatively weak stimuli (0.036 g) in all directions tested. Both EMG and EOG response gain slightly increased, while response phase lead decreased (with respect to stimulus velocity) as stimulus frequency increased in the range 0.25–1.39 Hz. Otolith contribution to compensatory eye and neck responses increased with stimulus frequency, leading to EMG and EOG responses, which oppose the imposed displacement more and more. But the otolith system alone remained unable to produce perfect compensatory responses, even at the highest frequency tested. In contrast, optokinetic stimuli in the Z and Y directions evoked consistent and compensatory eye movement responses (OKR) in a lower frequency range (0.025–0.25 Hz). Increasing stimulus frequency induced strong gain reduction and phase lag. Oculo-neck coupling or eye-head synergy was found during optokinetic stimulation in the Z and Y directions. It was characterized by bilateral activation of neck extensors and flexors during upward and downward eye movements, respectively, and by ipsilateral activation of neck muscles during horizontal eye movements. These visually-induced neck responses seemed related to eye velocity signals. Dynamic properties of neck and eye responses were significantly improved when both inputs were combined (CS). Near perfect compensatory eye movement and neck muscle responses closely related to stimulus velocity were observed over all frequencies tested, in the three directions defined. The present study indicates that eye-head coordination processes during linear motion are mainly dependent on the visual system at low frequencies (below 0.25 Hz), with close functional coupling of OKR and eye-head synergy. The otolith system basically works at higher stimulus frequencies and triggers Synergist OOR and ONR. However, both sensorimotor subsystems combine their dynamic properties to provide better eyehead coordination in an extended frequency range and, as evidenced under VS condition, visual and otolith inputs also contribute to eye and neck responses at high and low frequency, respectively. These general laws on functional coupling of the eye and head stabilizing reflexes during linear motion are valid in the three directions tested, even though the relative weight of visual and otolith inputs may vary according to motion direction and/or kinematics.  相似文献   
105.
血清C—反应蛋白测定在女性盆腔包块鉴别诊断中的意义   总被引:2,自引:0,他引:2  
目的;探讨C-反应蛋白(CRP)测定对女性盆腔包块鉴别诊断的临床价值。方法:分别测定盆腔炎性包块、良恶性肿瘤患者及无盆腔包块正常妇女血清C-反应蛋白。结果:炎性包块组、恶性肿瘤组血清CRP水平极显著地高于良性肿瘤组和正常对照组(P<0.01),且炎性包块组血清CRP水平升高的程度远大于恶性肿瘤组(P<0.01);而良性肿瘤组血清CRP与正常对照组无显著差异(P>0.05),两者均在正常范围。结论:血清CRP极显著升高者,首先应考虑炎性包块;较显著升高者,在排除感染,创伤及其他引起CRP升高者外要考虑盆腔恶性肿瘤的可能;CRP在正常范围者炎性包块的可能性极小。说明血清CRP测定是女性盆腔包块鉴别诊断的有用手段。  相似文献   
106.
PURPOSE: Acute pouchitis is a troublesome complication after restorative proctocolectomy. Deficiency of fuel, especially short chain fatty acids (SCFA), produced by anaerobic bacterial fermentation of saccharides, is implicated in ulcerative and diversion colitis. Our hypothesis was that SCFA deficiency occurs in acute pouchitis, and correction of the deficiency is associated with resolution of pouchitis. METHODS: Thirty-two patients were studied, 10 with histologically confirmed acute pouchitis and 22 with healthy pouches. Stool concentrations of SCFA (acetic, propionic, butyric, and valeric acids) were determined by gas-liquid chromatography. Quantitative bacteriologic studies of stool were carried out, and four-quadrant pouch biopsies were assessed by a pathologist who was unaware of the clinical state. Patients with pouchitis were treated for six weeks with metronidazole and given dietary advice to increase their intake of fermentable saccharides. RESULTS: Stool concentrations of SCFA were significantly less in pouchitis patients compared with patients with healthy pouches (340 mol/g (range, 124–492) vs.93 (range, 44–136) P<0.01). No differences in anaerobic or aerobic counts were seen. Resolution of pouchitis was associated with a significant increase in SCFA, but anaerobic counts fell. CONCLUSION: Deficiency of SCFA is implicated in acute pouchitis Read at the meeting of The American Society of Colon and Rectal Surgeons, Orlando, Florida, May 8 to 13, 1994.  相似文献   
107.
The purpose of this study was to investigate the force-velocity (F/) relationship for the erector spinae muscles in submaximal activation movements, with particular attention to their response during lengthening movements and at lower shortening contraction velocities. Dynamic models that predict lower back muscle forces require reasonable representations of the modulating effect of instantaneous velocity. Ten males were observed performing trunk flexion and extension in the sagittal plane under constant load. Contraction velocities were measured as the first derivative from a devise sensitive to changes in spine curvature, and controlled by a visual feedback system while a constant load was applied through a chest harness. The erector spinae exhibited a yielding phenomenon which causes an abrupt drop in force during constant velocity stretching under constant, submaximal, stimulation. The findings were consistent with previous isovelocity muscle lengthening experiments. Yielding appeared dependent on the level of load/activation supporting the theory of a state-variableF/ relationship. The eccentric behaviour of the lower erectors (L3) seemed independent of velocity and length, while that of the upper erectors (T9) showed a dependence on length. At lower concentric velocities, concavity in torque-velocity curves was noted after a threshold velocity. The findings of this study strongly reinforce the notion that theF/ length relationship is not a continuous hyperbolic relationship during muscle shortening and that the commonly modelled force augmentation effect of lengthening is incorrect, at least for submaximal activation of the extensors of the lower back.  相似文献   
108.
The authors compared intensive pelvic floor exercise alone (A) with intensive pelvic floor exercise plus vaginal cones (B) in premenopausal women with mild to moderate stress urinary incontinence. Forty-six patients (mean 43±6 years) were randomized into two training groups and treated for 3 months. Pre- and post-therapy urethral pressure profiles at rest and under stress and subjective results were obtained from 29 patients. The subjective improvement rate of the compliant patients after 12 weeks was 85% in group A and 84% in group B. When the dropouts (9 in group A and 8 in group B) were included in the subjective results an overall improvement rate of 48% in group A and 52% in group B was obtained. In group A one pressure transmission ratio (PTR) improved significantly at 6 weeks and the position of maximum urethral closure pressure was shifted proximally at 12 weeks. In group B one PTR in the midurethra was improved significantly at 6 weeks. The other urodynamic parameters were unchanged. There were no differences between groups A and B in subjective results or urodynamic findings. These results suggest that intensive pelvic floor exercise with or without vaginal cones improves the symptoms of mild to moderate stress incontinence in about 85% of premenopausal women, but that it has little effect on urodynamic parameters. Vaginal cones provided no additional benefit but may be useful for women for whom closely supervised pelvic floor exercise is not available.Editorial Comment: It is becoming increasingly clear from the literature that pelvic floor muscle exercises are effective in improving continence in many women with straightforward stress incontinence. An appropriate quest continues to determine how the exercises can best be taught and done. This article demonstrates that with frequent supervision, similar continence status is achieved both with and without the use of vaginal cones. It would be interesting to compare outcomes with and without cones in women who saw a health care provider only once for their initial teaching. If cones were found to be more effective in this setting, that would be a great aid to primary care physicians.The authors state that there was no correlation between the cone weight and the degree of improvement of symptoms: however, only 2 of the subjects progressed to the next heaviest cone weight. My understanding of the principles of athletic muscles training is that as one increases the resistance the muscle fibers hypertrophy and strengthen. This is the principle behind building biceps. Body-builders or power-lifters continue to increase the amount of weight (resistance) they lift in order to increase bulk and strength. I wonder if this same principle is the reason for the differences in results between this study and the one by Peattie et al. quoted by the authors. My major concern is that people begin to devalue the amount of effort required to perform effective pelvic floor exercises and make assumptions that such exercises are not as good as a permanent surgical cure. I believe that we have not yet begun to develop really effective muscle strengthening regimens for the pelvic floor, and attitudes such as the above will only serve to inhibit our progress.  相似文献   
109.
PreliminaryevaluationofpelvicvascularbedisolationchemotherapyinthetreatmentofadvancedcervicalcarcinomaJiangSenandPostgraduate...  相似文献   
110.
本文对83例患者盆腔囊性肿块超声诊断结果与手术及病理检查进行对比,提高了超声诊断的准确性。同时结合中医辨证分型拟找寻出中医分型与超声诊断的内在联系,以提高中医诊疗水平  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号