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101.
W. Robert Anderson 《Ultrastructural pathology》1990,14(3):221-232
The sequential stages of bronchopulmonary dysplasia occurring in 18 infants after intensive respiratory therapy supplemented by oxygen in high concentrations were studied by correlative light, scanning, and transmission electron microscopy. Infant survival ranged from 3 to 225 days. The earliest stage was an exudative reaction with a predominance of hyaline membranes. This merged with a subacute reparative response that was replaced by a chronic fibroproliferative stage in infants of longest survival; this stage was complicated by pulmonary fibrosis and emphysema. Correlative scanning and transmission electron microscopy demonstrated that type 2 pneumocytes contributed significantly to the reparative fibroproliferative response by organization of hyaline membranes and reepithelialization of damaged septal walls. 相似文献
102.
大鼠三叉神经脊束间质核内内脏神经初级传入终末与NOS阳性投射神经元的联系 总被引:1,自引:0,他引:1
目的 探查间质核 (INV)内内脏传入终末与向臂旁核 (PBN)投射的NOS阳性神经元之间的联系。 方法 逆行、跨神经节追踪以及免疫荧光组织化学方法 ,结合激光共聚焦扫描显微镜观察。 结果 PBN内注射四甲基罗丹明 (TMR)后 ,逆行标记细胞主要位于注射侧的INV ,大多属 2 0 μm以下的中、小型细胞。NOS阳性细胞与TMR逆行标记细胞分布区域重叠。NOS TMR双标记细胞分别占NOS阳性细胞总数的 5 4 8% (17 31)和TMR逆行标记细胞总数的 34% (17 4 9)。舌咽和迷走神经内注射生物素化葡聚糖胺 (BDA)跨神经节标记的内脏神经初级传入终末点状膨体贴近双标记细胞胞体 ,呈紧密接触状。 结论 可能存在经INV向PBN投射的内脏伤害性信息传导通路 ,作为神经递质和神经信息分子的NO可能参与其内脏伤害性信息的传递和调控 相似文献
103.
介绍基于USB2.0接口的医用超声内窥镜旋转扫描成像的设计与实现。根据超声成像的特点,本系统采取脉冲回波成像方式,文中介绍了超声波激发、接收电路以及收发隔离电路。针对旋转扫描的特点,设计了基于FPGA的同步控制电路和基于USB2.0接口的数据传输电路。对采集到的原始图像,进行坐标变换,获得了按直角坐标显示的灰度图像。利用连续旋转马达对实际物体扫描成像的实验结果,验证了系统的正确性。 相似文献
104.
B超心脏图象轮廓的自动检测 总被引:6,自引:1,他引:6
本文提出若干应用横向决策过程的动态规划及序贯模式识别的新方法,充分利用帧间心脏轮廓的动态信息,从超声图象中自动检测、分离心脏的内壁和外壁。 相似文献
105.
106.
Zheng-Lin Jiang Hisao Yamaguchi Akira Takahashi Shingo Tanabe Noboru Utsuyama Toshitaka Ikehara Keiko Hosokawa Hiroyuki Tanaka Yohsuke Kinouchi Hiroshi Miyamoto 《European journal of applied physiology》1995,70(3):234-239
Cerebral blood volume flow and flow velocity have been reported to increase during dynamic exercise, but whether the two increase in parallel and whether both increases occur as functions of exercise intensity remain unsettled. In this study, blood flow velocity in the common carotid artery was measured using the Doppler ultrasound method in eight healthy male students during graded treadmill exercise. The exercise consisted of stepwise progressive increases and decreases in exercise intensity. The peak intensity corresponded to approximately 85% of maximal oxygen consumption. During this exercise, the heart rate (f
c), mean blood pressure (BP) in the brachial artery and mean blood flow velocity (cc) in the common carotid artery increased as functions of exercise intensity. At the peak exercise intensity, (f
c), BP and cc increased by 134.5%, 20.5% and 51.8% over the control levels before exercise (P < 0.01), respectively. The resistance index (RI) and pulsatility index (PI) were determined from the velocity profile and were expected to reflect the distal cerebral blood flow resistance. The RI and PI increased during the graded exercise, but tended to decrease at the highest levels of exercise intensity. As cc increased with increases in exercise intensity it would be expected that cerebral blood flow would also increase at these higher intensities. It is also suggested that blood flow velocity in the cerebral artery does not proportionately reflect the cerebral blood flow during dynamic exercise, since the cerebral blood flow resistance changes. 相似文献
107.
Summary This study investigated whether isokinetic strength training might induce changes in static and dynamic power already achieved as a result of isometric strength training. The subjects were twelve males. The isometric strength and dynamic power of elbow flexors were tested by means of an electric dynamometer and fly-wheel every two weeks. During the first 8 weeks all subjects trained the elbow flexors isometrically at four different positions of elbow joints. This training produced 27–36% gains in isometric strength and 34–46% in power. Thereafter the subjects were divided into two groups: the FG group who trained isokinetically at a fast velocity of 157·s–1, and the SG group at slow velocity of 73·s–1. After 6 weeks of training, the FG group produced a significant gain in power with light equivalent masses and the SG group did so with heavy equivalent masses. Neither group showed change in isometric strength. 相似文献
108.
Dynamic particle image velocimetry (PIV) was applied to the study of the flow field associated with prosthetic heart valves.
The results were compared with those of laser Doppler anemometry (LDA). Anatomically and antianatomically oriented Jyros (JR)
and St. Jude Medical (SJM) valves were compared in the mitral position to study the effects of valve design on the downstream
flow field. The experimental program used a dynamic PIV system utilizing high-speed, high-resolution video to map the true
time-resolved velocity field inside the simulated ventricle. This system was complemented by a study using the more traditional
LDA system for comparison. Based on the experimental data, the following general conclusions can be made. High-resolution
dynamic PIV can capture true chronological changes in the velocity and turbulence fields. It also produces very detailed velocity
and turbulence information comparable to the LDA results. In the vertical measuring plane that passes both the center of the
aortic and mitral valves (A-A section), the two valves (the SJM and the JR) show distinct circulatory flow patterns when the
valve is installed in the antianatomical orientation. Small differences in valve design can generate noticeable differences,
particularly during the accelerating flow phase. The SJM valve maintains a relatively high velocity through the central orifice;
the curved leaflets of the JR valve generate higher velocities with a divergent flow during the accelerating and peak flow
phases. In the velocity field directly below the mitral valve and normal to the previous measuring plane (B-B section), where
characteristic differences in valve design will be visible, symmetrical twin circulations were observed because of the divergent
nature of the flow generated by the two inclined half-disks installed in the antianatomical orientation. The SJM valve, with
a central downward flow near the valve, is contrasted with the JR valve, which has a peripheral downward circulation with
higher, turbulent stresses. 相似文献
109.
Professor K. M. Patil M. S. Srinath 《Medical & biological engineering & computing》1990,28(5):416-422
A new image-processing system, using a video digitiser with an IBM-compatible PC/AT, is developed for acquisition and processing
of low-contrast, lowintensity barographic images of both feet for assessment of pressure distribution during standing and
walking. Data displays, in the form of centres of pressures, isopressures contours, perspective views of pressures, grey scale
image and walking pressure patterns, combined image of walking pressures, paths of centres of pressures and pressure variations
with time, are developed. These have provided very useful and early information regarding the internal structural changes
in the bones of the foot and sites at risk of ulcer development in leprosy subjects and enable suitable corrective orthopaedic
procedures to be adopted.
unitl the end of November 1990, and will then return to the Indian Institute of Technology. 相似文献
110.
Luigi Abbondanza Luigi Abis Nicoletta Cardi Fabio Garbassi Riccardo Po 《Macromolecular chemistry and physics.》2003,204(11):1428-1438
Several syndiotactic polystyrene (sPS) samples have been synthesized by using different catalytic systems. Their stereochemistry has been determined by 13C NMR spectra in both the aliphatic CH2 and aromatic C1 resonance regions. The observed peaks have been unambiguously assigned to specific hexads and heptads, respectively, and their intensities have been used to draw the percent of defects (meso dyads) in the polymer chains. On the hypothesis that chain defects are at the origin of chain folding and thus determine the thickness of crystalline lamellae, we performed differential scanning calorimetry (DSC) analysis on the same samples, and their thermal parameters were measured. A model was developed to determine the amount of steric defects from the DSC melting‐peak profiles, and the results obtained were compared with the NMR results. A satisfactory agreement was found (correlation factor 0.96) in the explored range of defect concentrations (up to 2.5% of meso dyads). The possible influence of the extraction procedure of the amorphous fraction was found to be negligible. Thus, information on stereochemistry can be obtained from DSC experiments starting from as‐prepared (not extracted) samples.