全文获取类型
收费全文 | 109168篇 |
免费 | 9336篇 |
国内免费 | 3949篇 |
专业分类
耳鼻咽喉 | 1383篇 |
儿科学 | 1564篇 |
妇产科学 | 1637篇 |
基础医学 | 15256篇 |
口腔科学 | 1948篇 |
临床医学 | 12000篇 |
内科学 | 19004篇 |
皮肤病学 | 2459篇 |
神经病学 | 7636篇 |
特种医学 | 5245篇 |
外国民族医学 | 39篇 |
外科学 | 12343篇 |
综合类 | 9273篇 |
现状与发展 | 9篇 |
一般理论 | 19篇 |
预防医学 | 7121篇 |
眼科学 | 2981篇 |
药学 | 10278篇 |
48篇 | |
中国医学 | 3507篇 |
肿瘤学 | 8703篇 |
出版年
2024年 | 199篇 |
2023年 | 1171篇 |
2022年 | 3188篇 |
2021年 | 4478篇 |
2020年 | 2886篇 |
2019年 | 3081篇 |
2018年 | 3348篇 |
2017年 | 2844篇 |
2016年 | 3370篇 |
2015年 | 4623篇 |
2014年 | 5599篇 |
2013年 | 5690篇 |
2012年 | 8515篇 |
2011年 | 8461篇 |
2010年 | 5370篇 |
2009年 | 4421篇 |
2008年 | 5998篇 |
2007年 | 5844篇 |
2006年 | 5332篇 |
2005年 | 4961篇 |
2004年 | 3964篇 |
2003年 | 3620篇 |
2002年 | 3213篇 |
2001年 | 2368篇 |
2000年 | 2269篇 |
1999年 | 2065篇 |
1998年 | 1067篇 |
1997年 | 1093篇 |
1996年 | 876篇 |
1995年 | 765篇 |
1994年 | 644篇 |
1993年 | 536篇 |
1992年 | 950篇 |
1991年 | 885篇 |
1990年 | 769篇 |
1989年 | 787篇 |
1988年 | 743篇 |
1987年 | 720篇 |
1986年 | 609篇 |
1985年 | 591篇 |
1984年 | 447篇 |
1983年 | 381篇 |
1982年 | 264篇 |
1981年 | 247篇 |
1980年 | 212篇 |
1979年 | 319篇 |
1978年 | 266篇 |
1977年 | 185篇 |
1974年 | 209篇 |
1973年 | 230篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
脑卒中急性期白细胞反应及临床意义 总被引:12,自引:1,他引:11
脑卒中急性期大多数患者白细胞增多,表现为中性粒细胞计数与白细胞总数增高,脑出血组白细胞增高姓率高于脑梗塞组,而中性粒细胞增高发生率二组间无差别,外周血白细胞增高与临床神经功能缺损程度评分有密切关系,中性粒细胞计数越高,近期神经功能预后则越差。 相似文献
24.
Facial reanimation after acoustic neuroma excision is currently accomplished using a variety of surgical techniques. A multi-institutional survey of patient perceptions of facial reanimation success was accomplished by mailing a questionnaire to 809 randomly selected members of the Acoustic Neuroma Association. Four hundred sixty patients who underwent 296 reanimation procedures responded. Facial to hypoglossal nerve anastomosis, tarsorrhaphy, and upper eyelid implants were most frequently performed. The patient's estimations of initial deficit, spontaneous recovery, and overall satisfaction with the reanimation procedures are discussed. 相似文献
25.
26.
Dopamine differentially regulates dynorphin, substance P, and enkephalin expression in striatal neurons: in situ hybridization histochemical analysis. 总被引:14,自引:0,他引:14
Dopamine regulation of the levels of dynorphin, enkephalin, and substance P messenger RNAs in rat striatal neurons was analyzed with in situ hybridization histochemistry (ISHH). Relative levels of peptide mRNA expression in the patch and matrix compartments of the dorsolateral striatum were compared among control rats, rats treated for 10 d with apomorphine, rats with unilateral 6-hydroxydopamine (6-OHDA) lesions of the nigrostriatal dopaminergic system, and rats with nigrostriatal dopaminergic lesions followed 2 weeks later by 10 d of apomorphine treatment. Image analysis of ISHH labeling demonstrated that the number of neurons expressing each peptide mRNA remained constant, whereas the relative level of peptide mRNA per neuron changed significantly, depending on the experimental treatment. Dynorphin mRNA expression increased following chronic apomorphine treatment: striatal patch neurons increased to an average of 100% above control values, whereas striatal matrix neurons showed only a 25% increase. Dynorphin mRNA expression decreased following 6-OHDA lesions: patch neurons showed an average 75% reduction in expression, whereas matrix neurons showed no significant change. In animals with 6-OHDA lesions followed by apomorphine treatment, both patch and matrix neurons showed an average increase in dynorphin expression of 300% above control levels. Changes in dynorphin mRNA levels with these treatments were matched by qualitative changes in dynorphin immunoreactivity both in the striatum and in striatonigral terminals in the substantia nigra. Neither substance P nor enkephalin mRNA levels showed a significant difference between the striatal patch and matrix compartments in any experimental condition (in the dorsolateral striatum). Substance P mRNA expression was increased an average of 50% after 10 d of apomorphine treatment and showed an average decrease of 75% following 6-OHDA lesions of the mesostriatal system. There was no significant change in the expression of substance P mRNA in striatal neurons compared to control values in rats with combined 6-OHDA lesion and apomorphine treatment. Enkephalin mRNA expression was not significantly altered by chronic apomorphine treatment but showed an average increase per cell of some 130% above control levels following 6-OHDA-induced lesions of the mesostriatal system. In animals with a 6-OHDA lesion and apomorphine treatment, enkephalin mRNA was also elevated but not significantly above the levels produced by the lesions alone. These data show that the expression of dynorphin, enkephalin, and substance P is differentially regulated by the mesostriatal dopaminergic system and, further, suggests that the mechanisms by which this regulation occurs may be different for the 3 peptide families. 相似文献
27.
28.
Magnetic resonance imaging confirmation of resolution of periodontoid pannus formation following C1/C2 posterior transarticular screw fixation. 总被引:3,自引:0,他引:3
Chronic odontoid fractures are considered unstable spinal lesions. Chronic instability in this region leads to the development of an inflammatory pannus, which can progress resulting in spinal cord compression radiographically and a myelopathy syndrome clinically. In this report we document three cases of reversal of pannus after C1/C2 transarticular screw fixation of an unstable odontoid fracture. Three patients were identified with chronic odontoid fractures and spinal cord compression due to periodontoid pannus formation. All patients presented with a progressive myelopathy syndrome. All patients underwent preoperative and postoperative magnetic resonance imaging (MRI) of the craniovertebral junction. C1/C2 transarticular screw fixation was performed for stabilization of C1/C2. Postoperatively there were no complications. Postoperative MRI at 6 months demonstrated resolution of the ventral pannus. Moreover, all patients exhibited improvement of preoperative neurological deficits. MRI is the imaging technique of choice for diagnosis and follow-up of patients with chronic odontoid fractures and ventral pannus. C1/C2 transarticular screw fixation provides a viable method for spinal stabilization in this region. In addition, stabilization can result in resolution of inflammatory pannus formation secondary to instability of the C1/C2 articulation. 相似文献
29.
Spontaneous neuronal hyperactivity in the medial and intralaminar thalamic nuclei of patients with deafferentation pain 总被引:6,自引:0,他引:6
Electrical activity was recorded from single cells in the thalamus of 10 patients with chronic pain associated with deafferentation. Under local anesthesia, these patients underwent either electrode implantation or thalamotomy for treatment of their pain. In eight of the 10 patients, single units were identified as discharging spontaneously in high-frequency, often rhythmic, bursts. The discharges were of two types: short bursts comprised of two to six spikes with a burst frequency of one to four per second; and long trains of 30 to 80 spikes of similar frequency. Reconstruction of electrode trajectories indicated that recordings were made from the region corresponding to the lateral aspect of the mediodorsal thalamic nucleus, the central lateral nucleus, a small part of the central median nucleus, and the parafascicular nucleus. In the eight patients in whom spontaneous neuronal burst activity was exhibited, it was impossible to study activity evoked by natural cutaneous stimulation due to the continuous spontaneous neuronal discharges. Both animal and human studies have suggested that pain related to deafferentation is accompanied by spontaneous hyperactivity in the dorsal horn of the spinal cord and in the ventral posterior thalamic nuclei. The authors present evidence of spontaneous neuronal hyperactivity in the intralaminar thalamic nuclei of patients with pain related to deafferentation. The findings suggest that spontaneous neuronal discharge in patients with pain related to deafferentation is more widespread in the central nervous system than has been previously appreciated. The results have important implications for the surgical treatment of chronic pain. 相似文献
30.
M K Song W Y Shin N F Adham N V Costea 《The American journal of clinical nutrition》1989,49(4):701-707
The effects of different amounts of dietary zinc on the Zn absorption rate and on Zn, calcium and magnesium concentrations in tissues of MOPC 104E tumor-bearing Balb/c mice were determined. The Zn absorption rate was inversely related to the amounts of Zn in their diets and was lower than that of nontumor-bearing control mice fed a laboratory mice chow. Zn concentrations of tumor-bearing mice were also low compared with control mice but tumor Zn concentrations, regardless of the concentrations of Zn in the diets, were higher than those of normal tissues of the host other than the pancreas. Ca concentrations in tumor and tissues of tumor-bearing mice were higher than in control animals but Mg concentrations in tissues of tumor-bearing mice appeared to be similar to those of control mice. Results suggest that tumor-bearing mice have a lower intestinal Zn absorption capacity and a higher Zn uptake rate causing other tissues to become hypozincemic and hypercalcemic. 相似文献