全文获取类型
收费全文 | 9434篇 |
免费 | 937篇 |
国内免费 | 2015篇 |
专业分类
耳鼻咽喉 | 171篇 |
儿科学 | 32篇 |
妇产科学 | 21篇 |
基础医学 | 1458篇 |
口腔科学 | 2437篇 |
临床医学 | 700篇 |
内科学 | 957篇 |
皮肤病学 | 61篇 |
神经病学 | 3347篇 |
特种医学 | 182篇 |
外科学 | 1273篇 |
综合类 | 897篇 |
现状与发展 | 8篇 |
预防医学 | 71篇 |
眼科学 | 166篇 |
药学 | 331篇 |
5篇 | |
中国医学 | 203篇 |
肿瘤学 | 66篇 |
出版年
2024年 | 7篇 |
2023年 | 150篇 |
2022年 | 177篇 |
2021年 | 389篇 |
2020年 | 356篇 |
2019年 | 331篇 |
2018年 | 343篇 |
2017年 | 489篇 |
2016年 | 532篇 |
2015年 | 356篇 |
2014年 | 752篇 |
2013年 | 1030篇 |
2012年 | 675篇 |
2011年 | 640篇 |
2010年 | 629篇 |
2009年 | 413篇 |
2008年 | 422篇 |
2007年 | 416篇 |
2006年 | 438篇 |
2005年 | 401篇 |
2004年 | 372篇 |
2003年 | 338篇 |
2002年 | 299篇 |
2001年 | 259篇 |
2000年 | 188篇 |
1999年 | 195篇 |
1998年 | 186篇 |
1997年 | 203篇 |
1996年 | 138篇 |
1995年 | 131篇 |
1994年 | 101篇 |
1993年 | 95篇 |
1992年 | 102篇 |
1991年 | 107篇 |
1990年 | 93篇 |
1989年 | 85篇 |
1988年 | 42篇 |
1987年 | 64篇 |
1986年 | 54篇 |
1985年 | 76篇 |
1984年 | 64篇 |
1983年 | 40篇 |
1982年 | 36篇 |
1981年 | 40篇 |
1980年 | 39篇 |
1979年 | 21篇 |
1978年 | 20篇 |
1977年 | 20篇 |
1976年 | 20篇 |
1974年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
湿性皮肤再生技术在皮肤擦伤的应用 总被引:2,自引:0,他引:2
目的:探导湿性皮肤再生技术治疗皮肤擦伤的疗效。方法:自2000年1月-2005年10月,治疗头面部、躯干和四肢急性皮肤擦伤共353例,其中采用湿润烧伤膏和暴露疗法治疗(新法组)185例,按传统疗法清创治疗(传统组)168例。结果:新法组7天内痊愈116例,占62.7%;14天内痊愈59例,占3713%;总有效率100%。传统组7天内痊愈82例,占48.8%;14天内痊愈58例,占34.5%;另外28例,占16.7%,发生不同程度的创面感染,痂下积脓,需作再次清创,碘伏湿敷或改用MEBO治疗,创面延期愈合,愈后瘢痕增生明显。结论:湿润烧伤膏和暴露疗法治疗皮肤擦伤与传统疗法比较,具有缩短创面愈合时间,愈后不留瘢痕等优点。 相似文献
43.
Axotomy of the rat facial nerve leads to increased CR3 complement receptor expression by activated microglial cells 总被引:5,自引:0,他引:5
Axotomy of the rat facial nerve leads to mitotic divisions of microglial cells without developing into phagocytes. In order to study the functional characteristics of those activated, i.e., proliferating but nonphagocytic, microglia we investigated the expression of monocyte/macrophage antigens by these cells. Our results show that activated microglia lack monocyte/macrophage antigens recognized by the monoclonal antibodies Ox-41, ED1, ED2, and Ki-M2R but express high levels of CR3 complement receptors in situ. 相似文献
44.
In order to determine whether the lateral ganglionic eminence (LGE) of the fetal telencephalon is the primary source of striatal precursors in striatal transplants and tissue cultures, cells derived exclusively from the LGE of fetal rat brains were transplanted into the quinolinic-acid-lesioned striatum of adult rats. After 2–3 months they produced grafts that were almost entirely AChE-positive as well as DARPP-32-, TH-, and calbindin-immunoreactive. The grafts were integrated into the host striatum so that host corticofugal fiber tracts interdigitated with graft tissues similar to the way they penetrate the gray matter of the normal striatum. Fast Blue dye injected into the ipsilateral globus pallidus of LGE grafted produced retrogradely labeled neurons within the grafts, but Fluorogold dye injected into the ipsilateral substantia nigra did not. In a separate experiment using DARPP-32-immunohistochemistry as a striatal marker, fetal (E16) and neonatal (P2) rat brains showed DARPP-32 immunoreactivity in the LGE but not in the adjacent medial ganglionic eminence (MGE). In summary, both fetal LGE cells and LGE grafts express specific striatal markers, and LGE grafts integrate into the host striatum and innervate the major striatal efferent target within the host brain. These data suggest that the LGE is the origin of cells committed to striatal phenotypes in the developing brain. 相似文献
45.
Ventricular-like and fast myosin heavy chains (VL-MHC and FMHC) are transiently expressed during slow skeletal muscle development. The influence of innervation on repression of these MHC isoforms is investigated over an 84-day time course in: (1) normal anterior latissimus dorsi (N-ALD) muscles, (2) regenerating ALD (R-ALD) muscles, (3) denervated ALD (D-ALD) muscles, and (4) regenerating and denervated ALD (RD-ALD) muscles. Western blotting demonstrates that the VL-MHC is expressed in R-, D-, and RD-ALD muscles, but not in N-ALD muscles. Expression of the VL-MHC is transient in R-ALD muscles. In contrast, VL-MHC expression persists in RD-ALD muscles, and appears with time in D-ALD muscles. FMHC was not detected in N-ALD muscles by Western blotting. Two FMHCs are seen in R-ALD and RD-ALD muscles, and in 13-day embryonic ALD muscles. The slower migrating FMHC (FMHCA) comigrates with developmentally regulated FMHCs in fast pectoralis muscle, while the faster migrating FMHC (FMHCB) comigrates with the faster migrating FMHC in embryonic ALD muscle (13 days in ovo). FMHCB decreases in amount over the time course in R-ALD muscles, while FMHCA persists. In contrast, substantial levels of both FMHCs persist in RD-ALD muscles, and appear with time in D-ALD muscles. The cellular distribution of MHCs is followed by immunocytochemistry. Regenerating cells expressing VL-MHC and FMHC are replaced by a mature population in R-ALD muscles. Some of the mature myofibers in R-ALD muscles express FMHC, but not VL-MHC. In RD-ALD and D-ALD muscles, both regenerating and mature muscle cells are seen which express VL-MHC and FMHC. Our results indicate that innervation is required for the repression of VL-MHC and FMHCB during regeneration of slow muscle. 相似文献
46.
N. R. Saunders A. Deal G. W. Knott Z. M. Varga† J. G. Nicholls † 《Clinical and experimental pharmacology & physiology》1995,22(8):518-526
1. Repair and recovery following spinal cord injury (complete spinal cord crush) has been studied in vitro in neonatal opossum (Monodelphis domestica), fetal rat and in vivo in neonatal opossum. 2. Crush injury of the cultured spinal cord of isolated entire central nervous system (CNS) of neonatal opossum (P4–10) or fetal rats (E15–E16) was followed by profuse growth of fibres and recovery of conduction of impulses through the crush. Previous studies of injured immature mammalian spinal cord have described fibre growth occurring only around the lesion, unless implanted with fetal CNS. 3. The period during which successful growth occurred in response to a crush is developmentally regulated. No such growth was obtained after P12 in spinal cords crushed in vitro at the level of C7–8. 4. In vivo, in the neonatal (P4–8) marsupial opossum, growth of fibres through, and restoration of, impulse conduction across the crush was apparent 1–2 weeks after injury. With longer periods of time after crushing a considerable degree of normal locomotor function developed. 5. By the time the operated animals reached adulthood, the morphological structure of the spinal cord, both in the region of the crush and on either side of the site of the lesion, appeared grossly normal. 6. The results are discussed in relation to the eventual longterm possibility of devising effective treatments for patients with spinal cord injuries. 相似文献
47.
Introduction - Axon growth and axon regeneration are complex processes requiring an adequate supply of certain metabolic precursors and nutrients. Material and methods - This article reviews the studies examining some of the processes of protein modification fundamental to both nerve regeneration and to the continuous and adequate supply of specific factors such as arginine, S-adenosylmethionine and polyamines. Results - The process of arginylation notably increases following nerve injury and during subsequent regeneration of the nerve, with the most likelyfunction of arginine-modification of nerve proteins being the degradation of proteins damaged through injury. It appears that defective methyl group metabolism may be one of the leading causes of demyelination, as suggested by the observation of reduced cerebrospinal fluid concentrations of s-adenosylmethionine (SAMe) and 5-methyltetrahydrofolate, the key metabolites in methylation processes, in patients with a reduction in myelination of corticospinal tracts. Polyamine synthesis, which depends strongly on the availability of both SAMe and arginine, markedly increases in neurons soon after an injury. This "polyamine-response" has been found to be essential for the survival ofthe parent neurons after injury to their axons. Polyamines probably exert their effects through involvement in DNA, RNA and protein synthesis, or through post-translational modifications that areindicated as the most relevant events of the "axon reaction." Conclusions - Nerve regeneration requires the presence of arginine, s-adenosylmethionine, and polyamines. Further studies are needed to explore the mechanisms involved in these processes. 相似文献
48.
An electron microscopic study of local anesthetic-induced skeletal muscle fiber degeneration and regeneration in the monkey 总被引:1,自引:0,他引:1
An electron microscopic study was done on abductor pollicis brevis muscles of 18 Rhesus monkeys after intramuscular injections of 0.75% bupivacaine, 2% mepivacaine, or 2% lidocaine + epinephrine. The muscles were examined for from 2 h to 28 days. Severe muscle fiber damage, consisting of breakdown of sarcolemma and myofibrils, was seen as early as 2 h. Phagocyte mediated fragmentation of the degenerating muscle fibers was at its peak during the third and fourth days. Myoblasts were abundant during the fourth day. Early myotubes appeared on the fifth and sixth days, and they matured during the second week. Satellite cells appeared alongside mature myotubes. Overall, the local anesthetic-induced breakdown and regeneration of skeletal muscle fibers in the monkey followed a course quite similar to that seen in the rat. 相似文献
49.
Adhesion in skeletal muscle during regeneration. 总被引:3,自引:0,他引:3
Adhesion molecules were studied in regenerating skeletal muscle immunohistochemically and ultrastructurally after a standardized trauma. In normal muscle, extracellular matrix (ECM) protein tenascin was restricted to myotendinous junctions (MTJ), while the integrin beta 1-subunit was present also on the sarcolemma. After injury, tenascin increased on the outer surface of regenerating myofibers, where cellular fibronectin also accumulated. Later, tenascin concentrated at the tips of regenerating myofibers, where new MTJs were formed. The beta 1-subunit disappeared on necrotized myofibers and reappeared on regenerating fibers in a thicker layer. The regenerating myofibers were invested by a basal lamina, except for the growth cones at the distal ends, which were laminin-negative until the formation of MTJs occurred. These results indicate that regenerating muscle cells are attached to the ECM in a way that allows both growth of the muscle cells across the scar and their use before the regeneration is completed. 相似文献
50.
Brainstem pieces from the trigeminal region of the metencephalic basal plate of 10-day chick embryos were dissociated and cultured in control conditions or in the presence of muscle-conditioned medium (MCM). The MCM was derived from age-matched target tissue relevant to this neuronal region (jaw musculature), from relevant target tissue of an age at which innervation would initially be taking place (4 days), and from nonrelevant target tissue also of an early stage (4-day limb bud). Neuronal survival and differentiation was assessed daily, for 7 days. Survival and differentiation were significantly enhanced by the 4-day jaw MCM compared to both the controls and the cultures grown with 10-day jaw MCM and 4-day limb MCM. These measures in the presence of 10-day jaw MCM and 4-day limb MCM did not differ, but surpassed that seen in control cultures. The results are compared to the more specific responsiveness seen in earlier (2-day) neural tube cultures, and their relationship to in vivo regenerative nerve fiber outgrowth is considered. 相似文献