全文获取类型
收费全文 | 20753篇 |
免费 | 5930篇 |
国内免费 | 126篇 |
专业分类
耳鼻咽喉 | 625篇 |
儿科学 | 616篇 |
妇产科学 | 690篇 |
基础医学 | 283篇 |
口腔科学 | 2643篇 |
临床医学 | 4135篇 |
内科学 | 5018篇 |
皮肤病学 | 454篇 |
神经病学 | 1794篇 |
特种医学 | 979篇 |
外科学 | 3749篇 |
综合类 | 54篇 |
现状与发展 | 12篇 |
预防医学 | 2681篇 |
眼科学 | 319篇 |
药学 | 182篇 |
中国医学 | 6篇 |
肿瘤学 | 2569篇 |
出版年
2024年 | 163篇 |
2023年 | 1089篇 |
2022年 | 353篇 |
2021年 | 627篇 |
2020年 | 1211篇 |
2019年 | 476篇 |
2018年 | 1319篇 |
2017年 | 1280篇 |
2016年 | 1497篇 |
2015年 | 1552篇 |
2014年 | 1950篇 |
2013年 | 2352篇 |
2012年 | 743篇 |
2011年 | 706篇 |
2010年 | 1341篇 |
2009年 | 1933篇 |
2008年 | 721篇 |
2007年 | 475篇 |
2006年 | 627篇 |
2005年 | 439篇 |
2004年 | 308篇 |
2003年 | 276篇 |
2002年 | 240篇 |
2001年 | 375篇 |
2000年 | 270篇 |
1999年 | 375篇 |
1998年 | 498篇 |
1997年 | 480篇 |
1996年 | 531篇 |
1995年 | 386篇 |
1994年 | 299篇 |
1993年 | 259篇 |
1992年 | 172篇 |
1991年 | 153篇 |
1990年 | 135篇 |
1989年 | 140篇 |
1988年 | 122篇 |
1987年 | 124篇 |
1986年 | 98篇 |
1985年 | 92篇 |
1984年 | 75篇 |
1983年 | 89篇 |
1982年 | 82篇 |
1981年 | 67篇 |
1980年 | 45篇 |
1979年 | 32篇 |
1978年 | 32篇 |
1977年 | 43篇 |
1976年 | 31篇 |
1975年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
152.
Taking occlusal photographs can be challenging; they are by far the most difficult images to obtain. Achieving an ideal photograph of every arch may not always be possible. In patients with limited range of motion of the mandible, an oversized or hyperactive tongue, an excessive gag reflex, or reduced flexibility of lips and checks, the goal of an ideal occlusal photograph may not be achieved. Nevertheless, patience, practice, and attention to detail can often provide a satisfactory result. 相似文献
153.
Jiange Qian MD Wenzhong Li PhD Guocheng Zhang MD Liangbin Yan MS Wei Sun PhD † 《Dermatologic surgery》2005,31(1):23-26
BACKGROUND: Preservation of hair follicle units for the purpose of delayed transplant will help us graft thousands of hair grafts at one session, even in a clinic with fewer assistants and less equipment. OBJECTIVE: This study was undertaken to evaluate and compare the viability of hair follicle units preserved at 0 and 4 degrees C for various periods. MATERIALS AND METHODS: Cell cultures and transplant of hair follicle units into athymic mice were performed. RESULTS: Outer root sheath cells could be cultivated in 96% (0 degrees C group) and 92% (4 degrees C group) of the hair follicles after 24 hours of preservation, whereas 85% (0 degrees C group) and 79% (4 degrees C group) of the follicles implanted into the mice regrew well after the same period of preservation. Then, in both the 0 degrees C and the 4 degrees C group, these rates decreased significantly with length of preservation in cell cultures and mice transplant; however, 0 degrees C seems better than 4 degrees C for preservation of grafts (p<.05). CONCLUSION: Grafts are better preserved at 0 degrees C instead of 4 degrees C. When delayed transplant is an option, it should be completed within 24 hours and no later than 48 hours. 相似文献
154.
Robert L. Kriel MD Linda E. Krach MD Martha M. Bergland MS Laurel A. Panser MS 《Pediatric neurology》1988,4(6):337-341
This report describes the outcomes of 28 children who had severe head injuries between 13–18 years of age. All were unconscious at least 24 hours and have been followed at least 2 years after injury. At present, their ages range from 18 to 27 years. Their educational achievements, social activities, marital status, functional independence, and employment at follow-up are described. 相似文献
155.
CANDYCE M. ROBERTS MS KATHRYN SUCHER ScD RD DONALD G. PERRIN PhD STEPHEN RODRIGUEZ PhD 《Journal of the American Dietetic Association》1995,95(8)
Concept mapping is an instructional strategy that requires learners to identify, graphically display, and link key concepts in instructional reading material. Although proven effective in numerous disciplines as a means to promote critical thinking and self-directed learning, concept mapping has not been tested in diet therapy. The objective of this study was to implement concept mapping as a small-group, cooperative learning strategy in an upper-division diet therapy course and to evaluate student attitudes about the effect of concept mapping on knowledge, self-directed learning, problem-solving, and collaborative skills. Students in the first semester (n=27) initially learned course material by lecture (4 weeks) followed by an integrated mapping/lecture format (12 weeks); the second semester (n=25) used an integrated mapping lecture format for the full 16 weeks. At the end of both semesters, students completed a 10-item original survey questionnaire. Responses for first (n=25) and second (n=21) semesters were analyzed independently. Results indicated that a majority of students thought participation in concept mapping enhanced knowledge of diet therapy principles (n=19 of 25; 18 of 21), self-directed learning (n=14 of 25; 18 of 21), critical thinking (n=21 of 25; 14 of 21), problem-solving (n=22 of 25; 16 of 21), and collaboration (n=24 of 25; 20 of 21) skills. When noncooperation of teammates was a factor, concept mapping was viewed as more frustrating and time consuming than lecture. This study demonstrated concept mapping as an effective learning strategy for diet therapy; it improves students’ ability to engage in self-directed learning, critical thinking, collaboration, and creative problem solving. Results suggest that concept mapping is most effective when accompanied with comprehensive training, coordinated lectures, instructor guidance, and long-term practice. J Am Diet Assoc. 1995; 95:908–911. 相似文献
156.
Can nurses practice caring within a healthcare system that promotes codependency? Caring promotes mutual empowerment of all participants while codependent caring disempowers. Nurses are expected to practice caring with clients, The authors contend, however, that nursing, as historically and currently practiced within bureaucratic/patriarchal organizations, is founded on a vlue system that fosters codependency. Until nursing is practiced within the context of caring organizations and a caring healthcare system, nurses will continue to be powerless to shape their own practice as carers and burnout will continue to be a problem. 相似文献
157.
158.
Lee L. Eckhardt MD Amanda L. Farley MS Esther Rodriguez MD Karen Ruwaldt BS Daniel Hammill David J. Tester BS Michael J. Ackerman MD PhD Jonathan C. Makielski MD 《Heart rhythm》2007,4(3):323-329
BACKGROUND: Loss-of-function mutations in the KCNJ2 cause approximately 50% of Andersen-Tawil Syndrome (ATS) characterized by a classic triad of periodic paralysis, ventricular arrhythmia, and dysmorphic features. Do KCNJ2 mutations occur in patients lacking this triad and lacking a family history of ATS? OBJECTIVES: The purpose of this study was to identify and characterize mutations in the KCNJ2-encoded inward rectifier potassium channel Kir2.1 from patients referred for genetic arrhythmia testing. METHODS: Mutational analysis of KCNJ2 was performed for 541 unrelated patients. The mutations were made in wild type (WT) and expressed in COS-1 cells and voltage clamped for ion currents. RESULTS: Three novel missense mutations (R67Q, R85W, and T305A) and one known mutation (T75M) were identified in 4/249 (1.6%) patients genotype-negative for other known arrhythmia genes with overall incidence 4/541 (0.74%). They had prominent U-waves, marked ventricular ectopy, and polymorphic ventricular tachycardia but no facial/skeletal abnormalities. Periodic paralysis was present in only one case. Outward current was decreased to less than 5% of WT for all mutants expressed alone. Co-expression with WT (simulating heterozygosity) caused a marked dominant negative effect for T75M and R82W, no dominant negative effect for R67Q, and a novel selective enhancement of inward rectification for T305A. CONCLUSIONS: KCNJ2 loss of function mutations were found in approximately 1% of patients referred for genetic arrhythmia testing that lacked criteria for ATS. Characterization of three new mutations identified a novel dominant negative effect selectively reducing outward current for T305A. These results extend the range of clinical phenotype and molecular phenotype associated with KCNJ2 mutations. 相似文献
159.
TRACY B. BRAMLETTE MD MPH DAVID H. LAWSON MD CARL V. WASHINGTON MD EMIR VELEDAR PHD BARRY R. JOHNS MD STACEY F. BRISMAN MD LIANA ABRAMOVA MD SUEPHY C. CHEN MD MS 《Dermatologic surgery》2007,33(1):11-16
BACKGROUND: Patients with thick (Breslow>4 mm) primary melanoma and/or regional nodal metastasis have a high risk of tumor recurrence. High-dose adjuvant interferon (IFN) alfa-2b offers/=50% risk of recurrence/disease-related mortality and offered IFN. Telephone surveys delineated reasons behind patients' decisions to accept IFN. RESULTS: Acceptors, 60 of 135 (45%), decided to take IFN alfa-2b whereas 75 of 135 (55%) declined. Being female (OR, 2.4; 95% CI, 1.17-5.03; p=.017) and positive SLN status (OR, 2.2; 95% CI, 1.01-4.97; p=.048) were strongly associated with patients who chose IFN. Acceptors of IFN were younger, more influenced by physicians, and less affected by depression and side effect profile (p<.05 for all). Decliners were more concerned by strained relationships with family and social life (p<.05). CONCLUSIONS: Gender and positive SLN were predictive of high-risk melanoma patients' acceptance of IFN treatment. Physician insight into melanoma patients' therapeutic decision-making process can guide patients through this difficult disease. 相似文献
160.
S. van Ruth† EBL van Dorst‡ MR Canninga-van Dijk§ MS de Bruin-Weller† 《Journal of the European Academy of Dermatology and Venereology》2007,21(5):678-680
Cutaneous metastasis of vaginal carcinoma is extremely rare. So far, the total number of reported skin metastasis of vaginal carcinoma is only one. We present another case with an unusual manifestation of vagina carcinoma metastasis: skin metastasis presenting as a leg ulcer on the lower leg. 相似文献