全文获取类型
收费全文 | 14351篇 |
免费 | 1132篇 |
国内免费 | 270篇 |
专业分类
耳鼻咽喉 | 216篇 |
儿科学 | 181篇 |
妇产科学 | 129篇 |
基础医学 | 1647篇 |
口腔科学 | 817篇 |
临床医学 | 1789篇 |
内科学 | 1291篇 |
皮肤病学 | 116篇 |
神经病学 | 724篇 |
特种医学 | 1005篇 |
外科学 | 2027篇 |
综合类 | 1261篇 |
预防医学 | 2039篇 |
眼科学 | 1517篇 |
药学 | 569篇 |
4篇 | |
中国医学 | 205篇 |
肿瘤学 | 216篇 |
出版年
2024年 | 42篇 |
2023年 | 282篇 |
2022年 | 534篇 |
2021年 | 624篇 |
2020年 | 574篇 |
2019年 | 600篇 |
2018年 | 590篇 |
2017年 | 513篇 |
2016年 | 527篇 |
2015年 | 470篇 |
2014年 | 828篇 |
2013年 | 1092篇 |
2012年 | 648篇 |
2011年 | 668篇 |
2010年 | 607篇 |
2009年 | 576篇 |
2008年 | 624篇 |
2007年 | 648篇 |
2006年 | 567篇 |
2005年 | 510篇 |
2004年 | 453篇 |
2003年 | 385篇 |
2002年 | 348篇 |
2001年 | 322篇 |
2000年 | 250篇 |
1999年 | 228篇 |
1998年 | 208篇 |
1997年 | 208篇 |
1996年 | 210篇 |
1995年 | 168篇 |
1994年 | 137篇 |
1993年 | 133篇 |
1992年 | 127篇 |
1991年 | 108篇 |
1990年 | 83篇 |
1989年 | 71篇 |
1988年 | 82篇 |
1987年 | 69篇 |
1986年 | 63篇 |
1985年 | 72篇 |
1984年 | 82篇 |
1983年 | 61篇 |
1982年 | 55篇 |
1981年 | 55篇 |
1980年 | 38篇 |
1979年 | 29篇 |
1978年 | 41篇 |
1977年 | 37篇 |
1976年 | 43篇 |
1975年 | 29篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
目的:建立一套测定单个细胞内蛋白含量的新方法。方法:纯化培养乳鼠雪旺氏细胞,施加实验因素,通过间接免疫荧光法标记细胞内NGF蛋白,而后用流式细胞仪(适用于细胞悬液样品)或粘附细胞仪(适用于粘附细胞样品)进行测定。结果:流式细胞仪及粘附细胞仪均可得到每一实验组的精确测定结果,并能进行统计分析,提供统计图表和各种数据。结论:应用流式细胞仪或粘附细胞仪可对单个雪旺氏细胞内的NGF含量进行定量研究 相似文献
92.
Dr. P. R. Hoskins P. J. Fish W. N. McDicken C. Moran 《Medical & biological engineering & computing》1998,36(3):259-269
Many of the changes resulting from arterial disease can be measured, using Doppler ultrasound for measurement of blood velocity
and B-scan imaging for measurement of tissue structure and composition. Wall thickness, the degree of arterial narrowing and
plaque volume can be measured using B-scan imaging, and 3D ultrasound can be used to improve the accuracy of measurements
of plaque volume and for improved visualisation of complex arterial geometries. Measurement of the dynamic properties of the
arterial wall permits estimation of wall elasticity and plaque motion. From the Doppler signal, measurements of blood velocity
are used to estimate the degree of arterial narrowing and volumetric flow, although measurement errors can be large. Wall
shear stress can be estimated by measuring the velocity gradient at the vessel wall. The problems of inadequate spatial resolution
and interference from overlying tissue are largely removed when intravascular systems are used, and these have superior capability
in the assessment of arterial structure and tissue composition. However, measurement of quantities relating to blood flow
is more difficult using the intravascular approach, as the indwelling cather disturbs the blood flow pattern, and currently,
assessment of flow and vessel cross-section are not performed at the same site. 相似文献
93.
Continuous estimation of systolic blood pressure using the pulse arrival time and intermittent calibration 总被引:8,自引:0,他引:8
Chen W Kobayashi T Ichikawa S Takeuchi Y Togawa T 《Medical & biological engineering & computing》2000,38(5):569-574
A continuous noninvasive method of systolic blood pressure estimation is described. Systolic blood pressure is estimated by
combining two separately obtained components: a higher frequency component obtained by extracting a specific frequency band
of pulse arrival time and a lower frequency component obtained from the intermittently acquired systolic blood pressure measurements
with an auscultatory or oscillometric system. The pulse arrival time was determined by the time interval from QRS apex in
electrocardiogram to the onset of photoplethysmogram in a fingertip beat-by-beat via an oximetric sensor. The method was examined
in 20 patients during cardiovascular surgery. The estimated values of systolic blood pressure were compared with those measured
invasively using a radial arterial catheter. The results showed that the correlation coefficients between estimated values
and invasively obtained systolic blood pressure reached 0.97±0.02 (mean±SD), and the error remained within ±10% in 97.8% of
the monitoring period. By using a system with automatic cuff inflation and deflation to acquire intermittent systolic blood
pressure values, this method can be applicable for the continuous noninvasive monitoring of systolic blood pressure. 相似文献
94.
冠状动脉血管直径测量方法的研究 总被引:1,自引:0,他引:1
心脏是人体生命活动的重要器官,能否正常工作主要是由心血管系和心传导系决定。冠状动脉是给心脏供血的唯一途径,心肌能否得到足够的营养、保持连续有节奏地运动,完全取决于冠状动脉是否能不断地供给其营养。冠状动脉直径的测量以及血管直径参数对于反映心脏功能和疾病的诊断具有重要意义。文中提出一种新型的、简便的血管直径测量方法,利用计算得到的血管直径,我们就可以判别心血管狭窄位置。 相似文献
95.
J. J. Visser J. E. Hoogkamer M. F. Bobbert P. A. Huijing 《European journal of applied physiology》1990,61(5-6):453-460
Summary Lengths of muscle tendon complexes of the quadriceps femoris muscle and some of its heads, biceps femoris and gastrocnemius muscles, were measured for six limbs of human cadavers as a function of knee and hip-joint angles. Length-angle curves were fitted using second degree polynomials. Using these polynomials the relationships between knee and hip-joint angles and moment arms were calculated. The effect of changing the hip angle on the biceps femoris muscle length is much larger than that of changing the knee angle. For the rectus femoris muscle the reverse was found. The moment arm of the biceps femoris muscle was found to remain constant throughout the whole range of knee flexion as was the case for the medial part of the vastus medialis muscle. Changes in the length of the lateral part of the vastus medialis muscle as well as the medial part of the vastus lateralis muscle are very similar to those of vastus intermedius muscle to which they are adjacent, while those changes in the length of the medial part of the vastus medialis muscle and the lateral part of the vastus lateralis muscle, which are similar to each other, differ substantially from those of the vastus intermedius muscle. Application of the results to jumping showed that bi-articular rectus femoris and biceps femoris muscles, which are antagonists, both contract eccentrically early in the push off phase and concentrically in last part of this phase. 相似文献
96.
Recent advances in the development of transducers for the measurement of vertical and shear forces acting on the plantar surface
of the foot are reviewed. Barefoot and in-shoe discrete and matrix transducers are reviewed in terms of structure, operation,
performance and limitations. Examples of capacitive, piezoelectric, optical, conductive and resistive types of transducer
are presented. Where available, the current clinical status is specified. 相似文献
97.
Cornelis G. Olthof Johanna W. Baars John Wagstaff Ab J. M. Donker Hans Schneider Peter M. J. M. de Vries 《European journal of applied physiology》1993,67(2):168-173
Summary One of the most common side effects of treatment with recombinant interleukin-2 (IL-2) is capillary leakage. Its genesis is not completely understood. The aim of the study was to determine whether capillary leakage can be monitored by means of a non-invasive conductivity technique and to study its starting point. Eight patients with advanced renal cell cancer were studied in a medium care section of the Department of Medical Oncology, University Hospital over 4 days during treatment sessions of continuous, intravenously administered IL-2 (mean dose of 15.6 × 106 IU · m–2 · day –1). The fluid shift from the intravascular to the extra- and intracellular compartments was monitored by means of noninvasive conductivity measurements. Changes in blood volume were calculated from serial erythrocyte counts. The clinical parameters of capillary leakage (oliguria, positive fluid balance, and gain in mass) were recorded. The mean gain in mass was 9% after 4 days of IL-2 treatment. The extracellular fluid volume increased significantly [46 (SD 23.2)%; P < 0.01], whereas the intracellular fluid volume did not change. The increase in blood volume (BV) amounted to 7% (P < 0.05). The decline in albumin concentration was significantly more than the increase in BV [38 (SD 4.3) %; P < 0.01], indicating capillary albumin leakage. The main changes were observed after the 2nd day of treatment. From this study, it is suggested that conductivity measurements are a suitable method to monitor capillary leakage induced by IL-2, and could be used to detect the exact onset and severity of this leakage. The leakage started within the first 24 h of treatment and was detected as a fluid shift from the intravascular to the extracellular space, while the intracellular compartment remained stable. These measurements could be useful during intervention studies with the aim of preventing this adverse effect of IL-2. 相似文献
98.
本文报道用激光对100例成人肱骨头进行两维平面测量,即正位、侧位、左、右45°斜位肱骨头的半径、关节面高度、张角及表面面积等。其结果为:1.肱骨头关节面的张角平均为144.48±11.93°。2.肱骨头半径及高度分别为2.15±0.16 cm、1.56±0.24 cm。肱骨头关节面高度占近似球体直径的36.05%。3.肱骨头关节面的表面积为21.02±4.03 cm~2。4.激光测量比接触测量客观、准确,可以重复并易取得统一标准,为骨胳测量提供一种较好方法。根据所测肱骨头半径与关节面张角,即能绘出肱骨头关节面的图形,计算出关节面曲率。本文对设计、制造肱骨头提供了国人数据,也可为肱骨头生物力学的研究提供参考。 相似文献
99.
《The Knee》2022
BackgroundRestricted kinematically-aligned total knee arthroplasty (KA-TKA) is a reasonable modification to avoid the alignment outlier that may cause implant failure. However, despite a noted high incidence of constitutional varus in Japanese individuals, there has been no investigation into how many knees require the restriction in restricted KA-TKA (RKA-TKA) among Japanese patients. Therefore, we conducted a study using preoperative long-leg radiograms.MethodsWe studied long-leg radiographs of 228 knees in 114 consecutive patients. The numbers of knees within the safety range and their corrective osteotomy angle in the restriction algorithms advocated by Almaawi et al. (2017) and MacDessi et al. (2020) were evaluated.ResultsAccording to the algorithms used by Almaawi et al. and MacDessi et al., out of 228 knees, 46 (20%) and 39 (17%) fell within the safety range, respectively. The mean correction angles of the hip-knee-ankle angle, lateral distal femoral angle and medial proximal tibial angle were 2.8 ± 3.4°, 0.4 ± 1.4° and 2.4 ± 2.8° in the algorithm used by Almaawi et al., while they were −4.9 ± 4.7°, 1.1 ± 2.5° and −6.0 ± 3.4° in the algorithm used by MacDessi et al. Most of the knees needed to be restricted in order to perform RKA-TKA, regardless of the algorithm used.ConclusionsBased on a preoperative analysis of long-leg radiograms in a Japanese population, most knees fall out of the safety range in RKA-TKA. Surgeons must consider whether to allow component outlier or to perform corrective osteotomy that likely requires soft tissue release. 相似文献
100.
Niels Jrgensen Jrn Müller Aleksander Giwercman Jakob Visfeldt Henrik Mller Niels E. Skakkebk 《The Journal of pathology》1995,176(3):269-278
The origin of testicular germ cell tumours occurring during childhood is poorly understood. In adults, the classical seminomas and non-seminomas originate from carcinoma in situ of the testis, which can usually also be detected in seminiferous tubules adjacent to the tumours. In order to contribute with information regarding a possible association between carcinoma in situ and the childhood group of germ cell tumours, we investigated seminiferous tubules adjacent to 13 infantile yolk sac tumours, five infantile teratomas, and six adolescent germ cell tumours of various types, using morphological evaluation, immunohistochemical staining with markers for carcinoma in situ cells, and densitometric DNA measurement of the germ cells. We detected clear differences between the germ cell populations adjacent to adolescent and infantile germ cell tumours. The former were associated with both normal germ cells and carcinoma in situ cells. The presence of carcinoma in situ cells strongly suggested that the adolescent tumours arose from carcinoma in situ cells, like germ cell tumours occurring in adult men. Although we were in doubt in two cases, the infantile germ cell tumours were in general not associated with carcinoma in situ cells. The aetiology of infantile yolk sac tumours and teratomas may therefore be fundamentally different from that of adolescent and adult germ cell tumours. The origin of yolk sac tumours and teratomas remains to be elucidated. 相似文献