全文获取类型
收费全文 | 53713篇 |
免费 | 4201篇 |
国内免费 | 461篇 |
专业分类
耳鼻咽喉 | 889篇 |
儿科学 | 1057篇 |
妇产科学 | 1087篇 |
基础医学 | 8565篇 |
口腔科学 | 815篇 |
临床医学 | 4989篇 |
内科学 | 10705篇 |
皮肤病学 | 1746篇 |
神经病学 | 4592篇 |
特种医学 | 2882篇 |
外科学 | 6481篇 |
综合类 | 588篇 |
现状与发展 | 1篇 |
一般理论 | 16篇 |
预防医学 | 3394篇 |
眼科学 | 1397篇 |
药学 | 4616篇 |
中国医学 | 454篇 |
肿瘤学 | 4101篇 |
出版年
2023年 | 325篇 |
2022年 | 854篇 |
2021年 | 1409篇 |
2020年 | 775篇 |
2019年 | 1192篇 |
2018年 | 1369篇 |
2017年 | 1080篇 |
2016年 | 1569篇 |
2015年 | 2041篇 |
2014年 | 2415篇 |
2013年 | 2821篇 |
2012年 | 4036篇 |
2011年 | 3915篇 |
2010年 | 2391篇 |
2009年 | 1968篇 |
2008年 | 2820篇 |
2007年 | 2815篇 |
2006年 | 2550篇 |
2005年 | 2397篇 |
2004年 | 2049篇 |
2003年 | 1810篇 |
2002年 | 1667篇 |
2001年 | 1070篇 |
2000年 | 1029篇 |
1999年 | 890篇 |
1998年 | 396篇 |
1997年 | 359篇 |
1996年 | 317篇 |
1995年 | 304篇 |
1994年 | 254篇 |
1993年 | 268篇 |
1992年 | 625篇 |
1991年 | 655篇 |
1990年 | 564篇 |
1989年 | 615篇 |
1988年 | 598篇 |
1987年 | 592篇 |
1986年 | 512篇 |
1985年 | 522篇 |
1984年 | 408篇 |
1983年 | 337篇 |
1982年 | 250篇 |
1981年 | 226篇 |
1980年 | 206篇 |
1979年 | 311篇 |
1978年 | 276篇 |
1977年 | 194篇 |
1974年 | 218篇 |
1973年 | 233篇 |
1972年 | 192篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
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
2.
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
3.
H Ku?nierczyk J Matuszyk C Radzikowski 《Archivum immunologiae et therapiae experimentalis》1989,37(5-6):547-556
The alkylating agent ifosfamide synthesized according to own method at the Institute of Pharmaceutical Industry, Warsaw, was compared in biological evaluations with Holoxan (Asta-Werke's ifosfamide). No significant differences between tested compounds were found in respect of acute toxicity and antitumor activity in experimental systems in mice. 相似文献
4.
5.
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
6.
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
7.
白纹伊蚊在竹林里孳生的阳性比为75.4%;而在竹林包围的居民区阳性比为15.3%。白纹伊蚊在居民区孳生密度布雷图指数为19.4,容器指数为6.2%。居民区孳生蚊虫的主要场所是泡菜坛,泡菜坛主要孳生蚊种是骚扰阿蚊,阳性比为73.7%,其次是淡色库蚊为20.2%,贪食库蚊为14.0%,白纹伊蚊最低,为9.1%。 相似文献
8.
Yang Hee Kim Young In Moon Young Hee Kang Jung Sook Kang 《Nutrition Research And Practice》2007,1(4):298-304
This study was conducted to investigate the hypocholesterolemic effect of simvastatin (30 mg/kg BW) and antioxidant effect of coenzyme Q10 (CoQ10, 15 mg/kg BW) or green tea (5%) on erythrocyte Na leak, platelet aggregation and TBARS production in hypercholesterolemic rats treated with statin. Food efficiency ratio (FER, ADG/ADFI) was decreased in statin group and increased in green tea group, and the difference between these two groups was significant (p<0.05). Plasma total cholesterol was somewhat increased in all groups with statin compared with control. Plasma triglyceride was decreased in statin group and increased in groups of CoQ10 and green tea, and the difference between groups of statin and green tea was significant (p<0.05). Liver total cholesterol was not different between the control and statin group, but was significantly decreased in the group with green tea compared with other groups (p<0.05). Liver triglyceride was decreased in groups of statin and green tea compared with the control, and the difference between groups of the control and green tea was significant (p<0.05). Platelet aggregation of both the initial slope and the maximum was not significantly different, but the group with green tea tended to be higher in initial slope and lower in the maximum. Intracellular Na of group with green tea was significantly higher than the control or statin group (p<0.05). Na leak in intact cells was significantly decreased in the statin group compared with the control (p<0.05). Na leak in AAPH treated cells was also significantly reduced in the statin group compared with groups of the control and CoQ10 (p<0.05). TBARS production in platelet rich plasma was significantly decreased in the groups with CoQ10 and green tea compared with the control and statin groups (p<0.05). TBARS of liver was significantly decreased in the group with green tea compared with the statin group (p<0.05). In the present study, even a high dose of statin did not show a cholesterol lowering effect, therefore depletion of CoQ10 following statin treatment in rats is not clear. More clinical studies are needed for therapeutic use of CoQ10 as an antioxidant in prevention of degenerative diseases independent of statin therapy. 相似文献
9.
10.
Ho-Seong Han Jai Young Cho Yoo-Seok Yoon 《Journal of hepato-biliary-pancreatic sciences》2009,16(4):427-432
Many studies have recently reported on laparoscopic liver resection, although its development has been slow compared to laparoscopy in other fields. The indications for the location of laparoscopic liver resection have previously been limited to easily accessible lesions. Performing laparoscopic liver resection in the posterior and superior parts of the liver has been considered difficult due to inadequate exposure, the poor operative field and the difficulty with parenchymal dissection. Flexible endoscopy, high definition imaging and various kinds of equipment for parenchymal transection have been introduced for clinical use. In addition, much experience with this procedure has been accumulated at many centers. Accordingly, there are an increasing number of reports on laparoscopic liver resection in difficult locations. At our institution, the location of the tumor is no longer a limitation to laparoscopic liver resection. However, for safer laparoscopic liver resection, the patient positioning and trocar placement should be individualized according to the tumor location. The type of resection also may depend on the remaining liver’s functional capacity. We describe here the technical considerations for performing laparoscopic liver resection, including the technical considerations for performing laparoscopic liver resection for lesions located in the postero-superior segments of the liver. 相似文献