全文获取类型
收费全文 | 56892篇 |
免费 | 3988篇 |
国内免费 | 1089篇 |
专业分类
耳鼻咽喉 | 663篇 |
儿科学 | 857篇 |
妇产科学 | 881篇 |
基础医学 | 8189篇 |
口腔科学 | 880篇 |
临床医学 | 6221篇 |
内科学 | 10098篇 |
皮肤病学 | 1142篇 |
神经病学 | 4418篇 |
特种医学 | 2497篇 |
外国民族医学 | 5篇 |
外科学 | 7963篇 |
综合类 | 2685篇 |
现状与发展 | 7篇 |
一般理论 | 55篇 |
预防医学 | 3576篇 |
眼科学 | 1442篇 |
药学 | 5005篇 |
15篇 | |
中国医学 | 1084篇 |
肿瘤学 | 4286篇 |
出版年
2024年 | 87篇 |
2023年 | 664篇 |
2022年 | 1514篇 |
2021年 | 2512篇 |
2020年 | 1364篇 |
2019年 | 1809篇 |
2018年 | 2005篇 |
2017年 | 1533篇 |
2016年 | 1811篇 |
2015年 | 2339篇 |
2014年 | 3048篇 |
2013年 | 3356篇 |
2012年 | 5067篇 |
2011年 | 5180篇 |
2010年 | 2873篇 |
2009年 | 2500篇 |
2008年 | 3629篇 |
2007年 | 3483篇 |
2006年 | 3115篇 |
2005年 | 2921篇 |
2004年 | 2375篇 |
2003年 | 2058篇 |
2002年 | 1702篇 |
2001年 | 816篇 |
2000年 | 808篇 |
1999年 | 647篇 |
1998年 | 370篇 |
1997年 | 296篇 |
1996年 | 211篇 |
1995年 | 187篇 |
1994年 | 169篇 |
1993年 | 127篇 |
1992年 | 179篇 |
1991年 | 186篇 |
1990年 | 149篇 |
1989年 | 125篇 |
1988年 | 104篇 |
1987年 | 88篇 |
1986年 | 85篇 |
1985年 | 64篇 |
1984年 | 45篇 |
1983年 | 50篇 |
1982年 | 39篇 |
1981年 | 28篇 |
1980年 | 31篇 |
1979年 | 40篇 |
1978年 | 23篇 |
1977年 | 18篇 |
1976年 | 16篇 |
1974年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Gerald S. Lipshutz Harish Mahanty Sandy Feng Ryutaro Hirose Peter G. Stock Sang-Mo Kang rew M. Posselt Chris E. Freise 《American journal of transplantation》2005,5(2):366-373
With the introduction of more potent immunosuppressive agents, rejection has decreased in simultaneous pancreas/kidney transplant (SPK) recipients. However, as a consequence, opportunistic infections have increased. The purpose of this report is to outline the course of SPK patients who developed polyomavirus-associated nephropathy (PVAN). A retrospective review of 146 consecutive SPK recipients from January 1, 1996 to December 31, 2002 was performed. Immunosuppression, rejection and development of PVAN were reviewed. Nine patients were identified. All received induction with either OKT3 or thymoglobulin. Immunosuppression included tacrolimus/cyclosporine, MMF/azathioprine and sirolimus/prednisone. Two patients were treated for kidney rejection prior to the diagnosis of PVAN. Time to diagnosis was an average of 359.3 days post-transplantation. Immunosuppression was decreased but five ultimately lost function. However, none developed pancreatic abnormalities as demonstrated by normal glucose and amylase. Two underwent renal retransplantation after PVAN diagnosis and both have normal kidney function. PVAN was the leading cause of renal loss in SPK patients in the first 2 years after transplantation and is a serious concern for SPK recipients. The pancreas, however, is spared from evidence of infection, and no pancreatic rejection occurred when immunosuppression was decreased. 相似文献
32.
33.
34.
35.
PURPOSE: The pharmacology of methamphetamine is reviewed, and the effects of methamphetamine use on oral health are described. SUMMARY: Methamphetamine is a highly addictive amphetamine analogue, initially synthesized in 1919. Illicit methamphetamine use leads to devastating effects on health, particularly the dentition. Illegal production of methamphetamine has skyrocketed in recent years, as have the number of users. The chief complaint of methamphetamine users is xerostomia. Without the protective effects of saliva, caries development in these patients is rampant. The typical pattern of decay involves the facial and cervical areas of both the maxillary and mandibular teeth, with eventual progression to frank coronal involvement. The acidic substances used to manufacture this drug have also been implicated as a cause of tooth decay and wear in users, as has bruxism as a result of drug-induced hyperactivity. When possible, these patients should be referred to a dentist to improve their oral health status and minimize the potential for adverse cardiovascular sequelae. Other preventive measures for methamphetamine users include stimulating saliva flow and increasing fluoride supplementation. Pharmacists should also counsel users to avoid carbohydrate-rich soft drinks in favor of water. Oral moisturizers may also be effective. CONCLUSION: Methamphetamine use causes xerostomia secondary to sympathetic central nervous system activation, rampant caries caused by high-sugar intake in the absence of protective saliva, and bruxism as a result of hyperactivity. Practitioners should know how to recognize the signs of and manage the oral health of patients with a history of methamphetamine use. 相似文献
36.
37.
Ganapathy A Prasad Kenneth K Wang Lori S Lutzke Jason T Lewis Schuyler O Sanderson Navtej S Buttar Louis M Wong Kee Song Lynn S Borkenhagen Lawrence J Burgart 《Clinical gastroenterology and hepatology》2006,4(2):173-178
BACKGROUND & AIMS: The aim of this study was to assess the validity of frozen section analysis of endoscopic mucosal resection (EMR) specimens from Barrett's esophagus as compared with permanent sections for the detection of neoplasia. Frozen sections help to give immediate feedback for surgical procedures. It has not been determined whether EMR can be adequately interpreted by using frozen sections to aid endoscopists in completely resecting neoplastic lesions. METHODS: EMR specimens from Barrett's esophagus with high-grade dysplasia (HGD) and/or carcinoma were tested by frozen section. Pathologists evaluated EMR specimens for the depth of invasion as well as the appearance of clear margins of resection. The kappa statistic was calculated to assess the degree of agreement between the frozen section and permanent section diagnoses. RESULTS: Twenty-three consecutive patients underwent 30 EMRs with frozen section diagnosis. Frozen section revealed a carcinoma in 7 specimens (23%) and dysplasia in 20 (66%). Permanent sections found carcinoma in 8 specimens (26%), dysplasia in 19 specimens (63%), and normal or nondysplastic Barrett's esophagus in the remainder. The kappa statistic for the depth of invasion of EMR specimens was 0.93 (near perfect agreement). The kappa statistic for the margins of the EMR specimens was 0.80 (excellent agreement). CONCLUSIONS: This study indicated that frozen section analysis of esophageal EMR specimens is valid as compared with permanent section. This technique might allow rapid evaluation about the degree and depth of involvement of cancers. This allows physicians to make decisions regarding further therapy if margins are involved or decrease the use of EMR for histologically benign-appearing lesions. 相似文献
38.
Mark G Stokes Christopher D Chambers Ian C Gould Therese English Elizabeth McNaught Odette McDonald Jason B Mattingley 《Clinical neurophysiology》2007,118(7):1617-1625
OBJECTIVE: To examine the relationship between coil-cortex distance and effective cortical stimulation using transcranial magnetic stimulation (TMS) in the left and right motor cortex. We also compare the effect of coil-cortex distance using 50 and 70 mm figure-eight stimulating coils. METHODS: Coil-cortex distance was manipulated within each participant using 5 and 10 mm acrylic separators placed between the coil and scalp surface. The effect of cortical stimulation was indexed by resting motor threshold (MT). RESULTS: Increasing distance between the coil and underlying cortex was associated with a steep linear increase in MT. For each additional millimetre separating the stimulating coil from the scalp surface, an additional approximately 2.8% of absolute stimulator output (approximately 0.062 T) was required to reach MT. The gradient of the observed distance effect did not differ between hemispheres, and no differences were observed between the 50 and 70 mm TMS coils. CONCLUSIONS: Coil-cortex distance directly influences the magnitude of cortical stimulation in TMS. The relationship between TMS efficacy and coil-cortex distance is well characterised by a linear function, providing a simple and effective method for scaling stimulator output to a distance adjusted MT. SIGNIFICANCE: MT measured at the scalp-surface is dependent on the underlying scalp-cortex distance, and therefore does not provide an accurate index of cortical excitability. Distance-adjusted MT provides a more accurate index of cortical excitability, and improves the safety and efficacy of MT-calibrated TMS. 相似文献
39.
40.
用多粘菌素B琼脂糖亲和层析法清除内毒素,结果表明:5ml多粘菌素B层析柱的总吸附内毒素能力为450 μg,用此法可完全清除体液或各种液体中的内毒素,对血清及腹水中的内毒素也有明显的吸附作用,而其他各种主要成分(除内毒素外)经过处理后无明显改变。去氧胆酸是一种强有力的去污剂,可使已饱和的柱子复活,复活率达85%左右。该方法有简便,可靠,吸附能力大,柱子的复活率高等优点。本方法的建立为内毒素血症的治疗展示了新的前景。 相似文献