全文获取类型
收费全文 | 39284篇 |
免费 | 2445篇 |
国内免费 | 2178篇 |
专业分类
耳鼻咽喉 | 1535篇 |
儿科学 | 373篇 |
妇产科学 | 140篇 |
基础医学 | 5347篇 |
口腔科学 | 964篇 |
临床医学 | 3493篇 |
内科学 | 2472篇 |
皮肤病学 | 221篇 |
神经病学 | 9038篇 |
特种医学 | 1314篇 |
外国民族医学 | 2篇 |
外科学 | 6722篇 |
综合类 | 5030篇 |
预防医学 | 736篇 |
眼科学 | 2564篇 |
药学 | 1998篇 |
17篇 | |
中国医学 | 1140篇 |
肿瘤学 | 801篇 |
出版年
2024年 | 77篇 |
2023年 | 558篇 |
2022年 | 962篇 |
2021年 | 1270篇 |
2020年 | 1337篇 |
2019年 | 1159篇 |
2018年 | 1117篇 |
2017年 | 1391篇 |
2016年 | 1383篇 |
2015年 | 1335篇 |
2014年 | 2312篇 |
2013年 | 2358篇 |
2012年 | 1904篇 |
2011年 | 2104篇 |
2010年 | 1859篇 |
2009年 | 1737篇 |
2008年 | 1919篇 |
2007年 | 1914篇 |
2006年 | 1727篇 |
2005年 | 1482篇 |
2004年 | 1395篇 |
2003年 | 1270篇 |
2002年 | 1105篇 |
2001年 | 984篇 |
2000年 | 816篇 |
1999年 | 763篇 |
1998年 | 732篇 |
1997年 | 684篇 |
1996年 | 580篇 |
1995年 | 507篇 |
1994年 | 456篇 |
1993年 | 407篇 |
1992年 | 448篇 |
1991年 | 364篇 |
1990年 | 372篇 |
1989年 | 300篇 |
1988年 | 256篇 |
1987年 | 270篇 |
1986年 | 272篇 |
1985年 | 342篇 |
1984年 | 311篇 |
1983年 | 192篇 |
1982年 | 228篇 |
1981年 | 205篇 |
1980年 | 183篇 |
1979年 | 130篇 |
1978年 | 93篇 |
1977年 | 85篇 |
1976年 | 68篇 |
1975年 | 43篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
71.
目的:研究面神经撞击伤后面神经核内生长相关蛋白(GAP-43)的变化及高压氧(HBO)治疗的影响。方法:利用BIM-Ⅱ型生物撞击机致家兔右侧面神经干损伤,应用SP免疫组化染色法观察损伤后1、3、7、14和21天(分别用HBO治疗及不用HBO为对照)面神经核内GAP-43的变化,并用电镜观察面神经干超微结构变化。结果:面神经损伤第1天,伤侧面神经核区GAP-43样免疫反应性神经元(GLIN)开始增多,第14天其增多达到高峰,第21天逐渐下降。HBO治疗组伤后不同时期GLIN的增多明显高于对照组。伤后第21天,与对照组相比HBO组面神经干电镜观察可见较多的新生髓鞘。结论:HBO治疗可使伤后面神经核内GLIN增多,因而有助于面神经损伤后的修复与再生。 相似文献
72.
73.
Sherif M. Hassan Frans G.I. Jennekens George Wieneke Henk Veldman 《Neuromuscular disorders : NMD》1994,4(5-6):489-496
Changes in calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) at the motor endplates of botulinum toxin-paralysed rat muscles were investigated using immunohistochemistry. One day following toxin injection, a dramatic increase in CGRP-LI was detected at the motor endplates and within preterminal axons of the soleus and gastrocnemius muscles. The upregulation of CGRP-LI persisted throughout the period during which muscle fibres were paralysed and new neuromuscular junctions were being formed by the growing sprouts. Decline of CGRP-LI at the motor endplates coincided with clinical recovery. Both up- and down-regulation of CGRP-LI took place earlier in the soleus than in the gastrocnemius muscle. Up-regulation of CGRP-LI was also detected in a subpopulation of motor axons in the sciatic nerves and in the spinal motor neurons innervating the paralysed muscles. These results indicate that levels of CGRP are regulated, at least partly, by changes in the target innervation. They also suggest an important role for CGRP in the regenerative processes following muscle paralysis. 相似文献
74.
Rolf Gronas B. Eng Peter G. Kalman MD Daryl S. Kucey MD Graham A. Wright PhD 《Journal of magnetic resonance imaging : JMRI》1997,7(4):637-643
Flow-independent angiography (FIA), an approach that isolates arterial blood using MR relaxation characteristics rather than flow effects, was evaluated for application in peripheral vascular disease (PVD). First, pilot studies were conducted in which FIA coronal projection images were obtained from controls and symptomatic patients with PVD to assess clinical utility. All control images corresponded to the expected leg arterial anatomy with little interference from deep veins (one of five) and muscle (zero of five). Superficial venous signal was less well suppressed in comparison to deep veins (four of five). Images of symptomatic patients were less consistent with difficulty suppressing muscle and deep venous signal in some cases and edema when present. We then compared T2 values for muscle (T2m, tibialis anterior), arterial blood (femoral and popliteal arteries), and venous blood (femoral, popliteal, and saphenous veins) in controls (n = 8) and symptomatic patients with intermittent claudication (n = 5) or ischemic rest pain (n = 7). Changes in T2 measurements of various tissues accounted for poorer contrast in symptomatic patients. Patients with ischemic rest pain had significantly higher T2m compared with controls (T2m = 39.3 ± 2.1 (1 standard error of the mean [SEM]) versus 30.9 ± .4, P < .01). For all measurements, other than saphenous vein, variances were greater in symptomatic patients. To realize the inherent advantages of FIA for this clinical application, additional work on suppression of signals from muscle, veins, and edema is required. One promising approach involves shifting from projection images to three-dimensional acquisitions for improved tissue suppression. 相似文献
75.
目的:介绍带血管蒂前臂后皮神经电缆式移植修复上臂桡神经缺损的应用解剖、手术方法及临床效果。方法:在20侧成人上肢标本上,观测前臂后皮神经及桡侧副动脉的行程及外径,设计以桡侧副动脉为蒂的前臂后皮神经电缆式移植修复上臂桡神经缺损的新术式并应用于临床。结果:前臂后皮神经与桡侧副动脉伴行关系密切,具有形成带血管蒂前臂后皮神经转移的解剖学条件;前臂后皮神经横径2.0cm左右,可切取长度15.0cm左右,折叠后可以修复7.0cm左右的桡神经缺损。同时,术中发现神经供体断端出血活跃,说明带血供的前臂后皮神经移植的血供是可靠的。临床应用8例,神经缺损3.5~6.0cm,随访10个月~3年,效果满意。按陆裕朴介绍的评定标准:优4例,良3例,可1例。结论:该术式转移灵活,操作简单、安全、可靠,对供区影响小,是修复上臂桡神经缺损的一种有用的方法。 相似文献
76.
Scott A. Syverud MD J. Matthew Jenkins MD Robert A. Schwab MD Michael T. Lynch MD Kevin Knoop MD Alexander Trott MD 《Academic emergency medicine》1994,1(6):509-513
Objective: Mental nerve block is frequently used to aid repair of facial lacerations; both percutaneous and intraoral approaches to blocking this nerve are used, but have never been compared. The authors compared the two techniques for pain of administration and effectiveness of anesthesia. Methods: A prospective, randomized, single-blind, crossover study was conducted using ten healthy volunteers aged 22 to 33 years. Patients having prior experience with mental nerve blocks, lidocaine allergy, active oral/facial infection, or previous facial fractures were excluded. Bilateral mental nerve blocks were done using intraoral technique on one side and percutaneous technique on the other. Both techniques were used by the same investigator and were carried out with 27-gauge needles and 2.5 mL of 2% buffered lidocaine at room temperature injected over 20 seconds. The oral mucosa was topically anesthetized with viscous lidocaine for 1 minute prior to intraoral injection. The orders of the blocks and sides of the face anesthetized were randomized. Subjective and objective pain (visual-analog scale), efficacy (anesthesia of lower lip), time to onset, and duration of anesthesia were evaluated. Results: The intraoral technique was subjectively less painful than the percutaneous approach in nine of ten subjects (p = 0.02). Scores on the visual-analog pain scale were significantly lower for the intraoral technique (p = 0.03). Intraoral injection produced lower-lip anesthesia in 10/10 subjects versus 7/10 for percutaneous (p = 0.25). Times to onset (approximately 1–2 minutes) and durations of anesthesia (approximately one hour) were similar for the two techniques. Conclusion: The intraoral approach to the mental nerve block with adjunctive topical anesthesia was subjectively and objectively less painful than the percutaneous approach without adjunctive anesthesia. While the intraoral approach had a greater efficacy of lower-lip anesthesia and a longer duration of action, these differences were not statistically significant. 相似文献
77.
M. M. Ali S. Jayabalan M. Machnicki G. S. Sohal 《International journal of developmental neuroscience》2003,21(4):199-208
Virtually all cell types in the inner ear develop from the cells of the otic vesicle. The otic vesicle is formed by the invagination of non-neural ectodermal cells known as the otic placode. We investigated whether a recently described cell population, originating from the ventral part of the hindbrain neural tube known as the ventrally emigrating neural tube (VENT) cells, also contributes cells to the otic vesicle. The ventral hindbrain neural tube cells were labeled with the fluorescent vital dye DiI or replication-deficient retroviruses containing the LacZ gene in chick embryos on embryonic day 2, after the emigration of neural crest from this region. One day later, the labeled cells were detected only in the hindbrain neural tube. Shortly thereafter, the labeled cells began to appear in the eighth (vestibulocochlear) cranial nerve and otic vesicle. From embryonic day 3.5-5, the labeled cells were detected in the major derivatives of the otic vesicle, i.e. the endolymphatic duct, semicircular canals, utricle, saccule, cochlea, and vestibulocochlear ganglion. That the emigrated cells originated from the ventral part of the hindbrain neural tube was confirmed by focal application of DiI impregnated filter paper and with quail chimeras. It is concluded that, in addition to the otic placode cells, the otic vesicle also contains the ventrally emigrating neural tube cells, and that both cell populations contribute to the structures and cell types in the inner ear. It is well known that inductive signals from the hindbrain are required for the morphogenesis of the inner ear. The migration of the hindbrain neural tube cells into the otic vesicle raises the possibility that the inductive effect of the hindbrain might be mediated, at least in part, by the ventrally emigrating neural tube cells and that, therefore, a mechanism exists that involves cells rather than diffusible molecules only. 相似文献
78.
J. M. Vallat M. J. Leboutet M. O. Jauberteau F. Tabaraud P. Couratier F. Akani 《Muscle & nerve》1994,17(4):378-380
The so-called “widenings of the myelin lamellae” are thought to be specific ultrastructural features of peripheral nerve myelin in patients with peripheral neuropathy associated with a monoclonal dysglobulinemia of IgM type and antiglycolipid activity. We report here a case of Guillain–Barré syndrome with no evidence of serum monoclonal dysglobulinemia, presenting the typical widenings of the myelin lamellae in small-diameter myelinated fibers from a sural nerve biopsy. In view of the positive reaction with anti-C3d complement on direct immunofluorescence, an immunological mechanism may be involved in the widenings of the myelin lamellae. © 1994 John Wiley & Sons, Inc. 相似文献
79.
前臂骨间背侧神经断裂的显微外科治疗 总被引:1,自引:0,他引:1
从1988年8月以来,应用显微外科技术修复前臂骨间背侧神经断裂10例,4例行自体神经游离移植,6例直接缝合。经术后4月~1年随访8例,肌力恢复均在4级以上,疗效满意。讨论了有关诊断,手术注意事项,修复时间与疗效的关系。自体神经移植与直接缝合的疗效比较等。 相似文献
80.
Summary This study describes reduced motor nerve conduction velocity and increased resistance to hypoxia-induced conduction failure in sciatic nerves of rats after four weeks of streptozotocin-induced diabetes (both effects were significant at p <0.05). These changes occurred in the absence of any deficit in the steady-state ouabain-sensitive adenosine triphosphatase (ATPase) activity of sciatic nerve endoneurial homogenates. The addition of 10 nmol/l insulin to endoneurial homogenates from control animals resulted in a 34% increase in ouabain-sensitive ATPase activity and a 19% reduction in ouabain-insensitive ATPase activity (both p <0.01). This stimulation of ouabain-sensitive ATPase activity by insulin did not occur in homogenates from diabetic rats. Treating diabetic rats daily with the aldose reductase inhibitor, imirestat (1 mg/kg) improved nerve conduction velocity (p <0.05) but was without effect upon the resistance to hypoxic conduction blockade or the deficit in insulin-stimulated oubain-sensitive ATPase activity. These data suggest that in streptozotocin-diabetic rats the functional disorders of reduced motor nerve conduction velocity and increased resistance to hypoxic conduction blockade do not share a common aetiology and that impaired nerve conduction is not related to reduced maximal potential oubain-sensitive ATPase activity. 相似文献