全文获取类型
收费全文 | 5906篇 |
免费 | 356篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 83篇 |
儿科学 | 588篇 |
妇产科学 | 106篇 |
基础医学 | 732篇 |
口腔科学 | 119篇 |
临床医学 | 359篇 |
内科学 | 1153篇 |
皮肤病学 | 294篇 |
神经病学 | 298篇 |
特种医学 | 182篇 |
外科学 | 564篇 |
综合类 | 171篇 |
一般理论 | 3篇 |
预防医学 | 354篇 |
眼科学 | 234篇 |
药学 | 508篇 |
中国医学 | 24篇 |
肿瘤学 | 504篇 |
出版年
2023年 | 42篇 |
2022年 | 113篇 |
2021年 | 215篇 |
2020年 | 141篇 |
2019年 | 161篇 |
2018年 | 197篇 |
2017年 | 118篇 |
2016年 | 144篇 |
2015年 | 150篇 |
2014年 | 256篇 |
2013年 | 291篇 |
2012年 | 369篇 |
2011年 | 370篇 |
2010年 | 218篇 |
2009年 | 182篇 |
2008年 | 252篇 |
2007年 | 247篇 |
2006年 | 235篇 |
2005年 | 227篇 |
2004年 | 186篇 |
2003年 | 163篇 |
2002年 | 144篇 |
2001年 | 142篇 |
2000年 | 113篇 |
1999年 | 112篇 |
1998年 | 46篇 |
1997年 | 32篇 |
1996年 | 42篇 |
1995年 | 28篇 |
1994年 | 41篇 |
1993年 | 35篇 |
1992年 | 85篇 |
1991年 | 91篇 |
1990年 | 93篇 |
1989年 | 77篇 |
1988年 | 69篇 |
1987年 | 79篇 |
1986年 | 58篇 |
1985年 | 61篇 |
1984年 | 64篇 |
1983年 | 46篇 |
1982年 | 63篇 |
1981年 | 72篇 |
1980年 | 70篇 |
1979年 | 55篇 |
1978年 | 33篇 |
1977年 | 26篇 |
1976年 | 32篇 |
1973年 | 31篇 |
1970年 | 26篇 |
排序方式: 共有6276条查询结果,搜索用时 15 毫秒
61.
62.
Hyperglycemia exaggerates ischemia-reperfusion-induced cardiomyocyte injury: reversal with endothelin antagonism 总被引:8,自引:0,他引:8
Verma S Maitland A Weisel RD Li SH Fedak PW Pomroy NC Mickle DA Li RK Ko L Rao V 《The Journal of thoracic and cardiovascular surgery》2002,123(6):1120-1124
OBJECTIVES: We have previously demonstrated an importance of endothelin-1 in diabetic patients undergoing bypass surgery. Recent evidence suggests that cardiomyocytes might also produce endothelin-1, which might directly impair myocyte contractility by increasing intracellular calcium levels. Because hyperglycemia is a potent stimulus of endothelin-1 production, we hypothesized that increased production, action, or both of endothelin-1 might be a mediator of direct cardiomyocyte injury in diabetes. Therefore we studied the effects of endothelin receptor blockers (BQ-123 and bosentan) on hyperglycemia-induced endothelin-1 production and cellular injury after ischemia-reperfusion. METHODS: Using a human ventricular heart cell model of simulated ischemia-reperfusion, we studied the effects of normoglycemia (5 mmol/L, 48 hours) and hyperglycemia (25 mmol/L, 48 hours) on cellular injury and endothelin-1 production. Furthermore, the effects of selective endothelin-A and mixed endothelin-A/B receptor antagonism (with BQ-123 and bosentan, respectively) were evaluated. RESULTS: Cellular injury, as assessed by means of trypan blue uptake, was higher in human ventricular heart cells subjected to hyperglycemia and simulated ischemia-reperfusion injury (P =.01); this effect was prevented with both BQ-123 and bosentan (P =.01). In addition, heart cells from the hyperglycemic group elaborated more endothelin-1 after ischemia-reperfusion (P =.02). CONCLUSIONS: Endothelin-1 production and cellular injury were greater in human ventricular heart cells subjected to hyperglycemic conditions and simulated ischemia-reperfusion. These effects are mediated by endothelin-A receptors because both BQ-123 and bosentan exerted similar degrees of protection. Endothelin receptor blockade is a novel strategy to improve the resistance of the diabetic heart to cardioplegic arrest and reperfusion. 相似文献
63.
Ursodeoxycholic Acid Enhances Fractional Calcium Absorption in Primary Biliary Cirrhosis 总被引:2,自引:0,他引:2
A. Verma J. D. Maxwell L. Ang T. Davis S. Hodges T. C. Northfield M. Zaidi M. Pazianas 《Osteoporosis international》2002,13(8):677-682
Bone disease is a frequently reported complication in primary biliary cirrhosis (PBC), but its pathogenesis is poorly understood.
Calcium malabsorption has been considered as an important contributing factor. Ursodeoxycholic acid (UDCA) is the treatment
of choice in PBC, improving survival, but its effect on calcium absorption is unknown. In this study, we have measured fractional
calcium absorption, using a single isotope method, in a group of female PBC patients (median age: 60 years, range: 46–78 years)
and age-matched female controls (median age: 58 years, range: 36–74). Bone mineral density (BMD) in PBC patients was significantly
lower than age-matched controls (g/cm2± SEM; lumbar spine: controls 1.139 ± 0.028, PBC patients 1.004 ± 0.026, p= 0.0028; femoral neck: controls 0.944 ± 0.034, PBC patients 0.819 ± 0.023, p = 0.0032). Twenty two PBC patients, who were not vitamin D-deficient, were off and on UDCA for ~1 month and ~8 weeks, respectively.
Fractional calcium absorption in PBC patients prior to UDCA treatment (mean ± SEM, 33.8 ± 2.6%) was significantly lower than
controls (52.0 ± 2.4%, p<0.001). Following UDCA therapy, fractional calcium absorption increased significantly (Off UDCA: 33.1 ± 2.6%, On UDCA: 36.6
± 2.5%, p<0.0058). Osteocalcin levels were significantly raised in the PBC group (mean ± SEM, ng/ml, 41.4 ± 2.02) compared to controls
(31.1 ± 2.64, p= 0.002). There were no differences in parathyroid hormone (PTH) or 25-hydroxyvitamin D levels between these two groups or
following UDCA therapy. In conclusion, we found that PBC patients display low spinal and femoral neck BMD, reduced fractional
calcium absorption, and elevated plasma osteocalcin. The calcium malabsorption is corrected partially by UDCA therapy. Long-term
studies are required to determine whether this effect can be sustained, and whether a sustained increase in fractional calcium
absorption can translate into a favorable change in bone strength in patients with PBC.
Received: 27 November 2001 / Accepted: 11 April 2002 相似文献
64.
Effect of highly purified capsaicin on articular cartilage and rotator cuff tendon healing: An in vivo rabbit study 下载免费PDF全文
Nicole A. Friel Allison G. McNickle Michael J. DeFranco FanChia Wang Elizabeth F. Shewman Nikhil N. Verma Brian J. Cole Bernard R. Bach Jr. Susan Chubinskaya Susan M. Kramer Vincent M. Wang 《Journal of orthopaedic research》2015,33(12):1854-1860
Highly purified capsaicin has emerged as a promising injectable compound capable of providing sustained pain relief following a single localized treatment during orthopedic surgical procedures. To further assess its reliability for clinical use, the potential effect of highly purified capsaicin on articular cartilage metabolism as well as tendon structure and function warrants clarification. In the current study, rabbits received unilateral supraspinatus transection and repair with a single 1 ml injection of capsaicin (R + C), PEG‐only placebo (R + P), or saline (R + S) into the glenohumeral joint (GHJ). An additional group received 1 ml capsaicin onto an intact rotator cuff (I + C). At 18 weeks post‐op, cartilage proteoglycan (PG) synthesis and content as well as cell viability were similar (p > 0.05) across treatment groups. Biomechanical testing revealed no differences (p > 0.05) among tendon repair treatment groups. Similarly, histologic features of both cartilage and repaired tendons showed minimal differences across groups. Hence, in this rabbit model, a single injection of highly purified capsaicin into the GHJ does not induce a deleterious response with regard to cartilage matrix metabolism and cell viability, or rotator cuff healing. These data provide further evidence supporting the use of injectable, highly purified capsaicin as a safe alternative for management of postoperative pain following GHJ surgery. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1854–1860, 2015. 相似文献
65.
Background
Children are vulnerable to musculoskeletal injuries both at home and on the street for various reasons. Morbidity and disabilities resulting from these, mostly preventable, injuries, make them a burden to their families and society. The role of various factors associated with injuries is often not documented.Methods
This prospective study, done on 100 children aged up to 12 years with musculoskeletal trauma, analysed in details, the various modes of injuries.Results
One in every five patient was a child below 12 years of age. Boys were injured more than girls. Injuries, especially fractures, were most common in the extremities, the upper limb more commonly injured than the lower limb. Most of the injuries occurred at home. The most common mode of injuries was falls that happened while playing both within and outside the home, followed by road traffic accidents. Most injuries occurred during daytime.Conclusions
Injuries in children were found to be preventable. Small interventions while constructing homes can contribute tremendously to injury prevention and control in children. Parental awareness about the various modes of injury, role of supervised playing and their responsibility towards injury prevention can play a key role in reducing the morbidity associated with childhood fractures. 相似文献66.
Beard and moustache reconstruction has gained more popularity and acceptance over the last decade. The procedure is done for the correction of facial areas with hair density deficit and also for the cosmetic enhancement of pre-existing facial hair. The surgical technique includes the harvesting of grafts from the scalp by the follicular unit excision (FUE) or follicular unit transplantation (FUT) technique and then placing them in either premade slits or by stick and place method. The advancement and refinement of procedure over the years has aided in achieving the optimal aesthetic results, with minimal side effects. 相似文献
67.
68.
69.
PURPOSE/BACKGROUND: Penetrating keratoplasty is the logical solution for the management of corneal opacities. In situations such as in Papua New Guinea, where donor corneal tissue is scarce and corneal opacities are plenty, an alternative procedure for the management of corneal opacities in the form of ipsilateral rotational autokeratoplasty was considered. METHODS: In the present prospective study, ipsilateral rotational autokeratoplasty was performed in 17 eyes over a 2 year period in a general hospital.The patient's cornea was trephined eccentrically and the corneal opacity was dialed out of the visual axis and was replaced by clear peripheral cornea. RESULTS: Most opacities were leucomata (76.4%). The average size of the opacity was 5.1 mm and the corneal button size was 7 mm.A final visual acuity of 6/18 or better was obtained in 64.7% of cases (at 12 months). No significant postoperative complications were encountered. No complex formula was needed to calculate the size of the button and, by simply adding 3 mm to the pupillary diameter in standard illumination, one could make an estimation of the graft diameter. CONCLUSIONS: Rotational autokeratoplasty has a definite role in places where donor corneal tissue is scarce, in patients in whom long-term steroids are a risk or in situations where follow up of patients is difficult. Rejection is a theoretical impossibility, but late endothelial failure could occur, requiring regrafting. Rotational autokeratoplasty should be seriously considered as an alternative to conventional penetrating keratoplasty. 相似文献
70.
Miyamura Y Verma IC Saxena R Murase A Kono M Suzuki T Yasue S Shibata S Sakakibara A Tomita Y 《Journal of dermatological science》2005,39(3):167-173
BACKGROUND: Many mutations of the tyrosinase gene have been reported in oculocutaneous albinism type I (OCA1) patient. In the future, a greater number of novel mutations will be found as the search for pathological mutations in the tyrosinase genes of OCA patients from various ethnic origins. For rapid determination in future whether an observed mutation is a polymorphism or a novel pathological one, sequence databases of the gene of various ethnic people are needed. OBJECTIVE: We established a sequence database of the tyrosinase gene of Japanese as well as Indian people. METHOD: We collected DNA from 109 Japanese and 103 Indians with normal pigmentation and analyzed their tyrosinase gene using a direct sequencing method. RESULT: The database shows an apparent difference between the two ethnic groups in polymorphisms of the tyrosinase gene namely, Q402 allele, Y192 allele and IV2+24 insT were found in the Indian population, but not in the Japanese. On the other hand, some Japanese had IV2-21 insT but none of the Indians did. The database supports the notion that the tyrosinase gene evolved and extended separately in the two ethnic groups. And the developing database confirmed that the reported mutations causing Indian and Japanese OCA were not among the polymorphisms in the database, which conversely gives genetical proof of the "genuine" pathological mutations. CONCLUSION: Eventually, the sequence database we established will contribute to demonstrating novel mutations of albinism in Indians and Japanese. 相似文献