全文获取类型
收费全文 | 10498篇 |
免费 | 562篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 217篇 |
儿科学 | 355篇 |
妇产科学 | 548篇 |
基础医学 | 1662篇 |
口腔科学 | 195篇 |
临床医学 | 733篇 |
内科学 | 1740篇 |
皮肤病学 | 504篇 |
神经病学 | 919篇 |
特种医学 | 448篇 |
外科学 | 1597篇 |
综合类 | 112篇 |
一般理论 | 8篇 |
预防医学 | 511篇 |
眼科学 | 248篇 |
药学 | 600篇 |
中国医学 | 6篇 |
肿瘤学 | 684篇 |
出版年
2022年 | 70篇 |
2021年 | 147篇 |
2020年 | 85篇 |
2019年 | 141篇 |
2018年 | 147篇 |
2017年 | 109篇 |
2016年 | 150篇 |
2015年 | 152篇 |
2014年 | 229篇 |
2013年 | 315篇 |
2012年 | 448篇 |
2011年 | 479篇 |
2010年 | 312篇 |
2009年 | 299篇 |
2008年 | 426篇 |
2007年 | 451篇 |
2006年 | 438篇 |
2005年 | 452篇 |
2004年 | 478篇 |
2003年 | 441篇 |
2002年 | 431篇 |
2001年 | 280篇 |
2000年 | 281篇 |
1999年 | 249篇 |
1998年 | 116篇 |
1997年 | 86篇 |
1996年 | 80篇 |
1995年 | 72篇 |
1994年 | 67篇 |
1993年 | 63篇 |
1992年 | 136篇 |
1991年 | 128篇 |
1990年 | 128篇 |
1989年 | 106篇 |
1988年 | 117篇 |
1987年 | 120篇 |
1986年 | 100篇 |
1985年 | 112篇 |
1984年 | 82篇 |
1983年 | 63篇 |
1981年 | 58篇 |
1979年 | 93篇 |
1978年 | 55篇 |
1977年 | 54篇 |
1975年 | 74篇 |
1973年 | 69篇 |
1971年 | 58篇 |
1970年 | 75篇 |
1969年 | 66篇 |
1913年 | 54篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
Ludwig Labler Marius Keel Otmar Trentz Michael Heinzelmann 《European spine journal》2006,15(9):1388-1396
The use of vacuum assisted closure (V.A.C.) therapy in postoperative infections after dorsal spinal surgery was studied retrospectively. Successful treatment was defined as a stable healed wound that showed no signs of acute or chronic infection. The treatment of the infected back wounds consisted of repeated debridement, irrigation and open wound treatment with temporary closure by V.A.C. The instrumentation was exchanged or removed if necessary. Fifteen patients with deep subfascial infections after posterior spinal surgery were treated. The implants were exchanged in seven cases, removed completely in five cases and left without changing in one case. In two cases spinal surgery consisted of laminectomy without instrumentation. In two cases only the wound defects were closed by muscle flap, the remaining ones were closed by delayed suturing. Antibiotic treatment was necessary in all cases. Follow up was possible in 14 patients. One patient showed a new infection after treatment. The study illustrates the usefulness of V.A.C. therapy as a new alternative management for wound conditioning of complex back wounds after deep subfascial infection. 相似文献
4.
5.
G J Wintemute J F Kraus S P Teret M A Wright 《American journal of preventive medicine》1988,4(6):343-348
Previous epidemiological studies of drowning in the United States have dealt primarily with children. The epidemiology and prevention of drowning in adulthood may be very different. To test this general hypothesis, we analyzed the 293 drownings occurring among Sacramento County residents 20 years of age and above during 1974 to 1985. Drowning rates were highest for men 20-29 years of age (11.5 per 100,000 population) and blacks (7.5 per 100,000 population). Swimmers, boaters, and motor vehicle occupants were most frequently represented. Alcohol use was involved in 48% of cases overall and 77% of those involving motor vehicle occupants. A history of seizure disorder was another contributing factor. Important differences do exist in drowning epidemiology between children and adults. Our results suggest that preventing drowning will be more problematic among adults than among children. The study was also used to test the sensitivity of two commonly used methods of case ascertainment for cases in Sacramento County. A manual review of coroner's records had a sensitivity of 96%. A computerized review of death certificate data from the state's vital statistics data base had a sensitivity of 79%. The sources and implications of these differences are discussed. 相似文献
6.
7.
Parastoo Jangouk Thomas Dehmel Gerd Meyer Zu Hörste Andreas Ludwig Helmar C. Lehmann Bernd C. Kieseier 《Glia》2009,57(16):1765-1774
The disintegrin and metalloproteinase 10 (ADAM10) is a membrane‐anchored metalloproteinase with both proteolytic and disintegrin characteristics. Here, we investigate the expression, regulation, and functional role of ADAM10 in axonal outgrowth and myelination of the peripheral nerve. Expression pattern analysis of 11 ADAM family members in co‐cultures of rat dorsal root ganglia (DRG) neurons and Schwann cells (SCs) demonstrated the most pronounced mRNA expression for ADAM10. In further studies, ADAM10 was found to be consistently upregulated in DRG‐SC co‐cultures before the induction of myelination. Neurons as well as SCs widely expressed ADAM10 at the protein level. In neurons, the expression of ADAM10 was exclusively limited to the axons before the induction of myelination. Inhibition of ADAM10 activity by the hydroxamate‐based inhibitors GI254023X and GW280264X resulted in a significant decrease in the mean axonal length. These data suggest that ADAM10 represents a prerequisite for myelination, although its activity is not required during the process of myelination itself as demonstrated by expression analysis of myelin protein zero (P0) and Sudan black staining. Hence, during the process of myelin formation, ADAM10 is highly upregulated and appears to be critically involved in axonal outgrowth that is a requirement for myelination in the peripheral nerve. © 2009 Wiley‐Liss, Inc. 相似文献
8.
Kerstin Schmidt Johannes Hoffend Annette Altmann Ludwig G Strauss Antonia Dimitrakopoulou-Strauss Britta Engelhardt Dirk Koczan J?rg Peter Thomas J Dengler Walter Mier Michael Eisenhut Uwe Haberkorn Ralf Kinscherf 《Journal of nuclear medicine》2006,47(3):543-551
Growth of malignant tumors is dependent on sufficient blood supply. Thus, inhibition of tumor angiogenesis is emerging as a promising target in the treatment of malignancies. Human angiostatin (hANG) is one of the most potent inhibitors of endothelial cell proliferation, angiogenesis, and tumor growth in vivo. However, its mechanisms operating in vivo are not well understood. METHODS: To obtain more information about functional changes in the angiogenic process, we established Morris hepatoma (MH3924A) cell lines expressing hANG (hANG-MH3924A). The effects of hANG expression on proliferation and apoptosis of human umbilical vein endothelial cells (HUVECs) were measured in coculture experiments in vitro. To evaluate changes in tumor perfusion and blood volume, H2 15O and 68Ga-DOTA-albumin (DOTA is 1,4,7,10-tetraazacyclododecane-N,N',N',N'-tetraacetic acid) were used for PET studies in vivo. Additionally, immunohistologic quantification of vascularization, apoptosis, and proliferation as well as gene array analyses were performed. RESULTS: Our in vitro experiments demonstrate reduced proliferation and increased apoptosis in HUVECs when being cocultured with hANG-MH3924A. In support, tumor growth of hANG-MH3924A is diminished by 95% in vivo. However, tumor perfusion and blood volume are increased in hANG-MH3924A corresponding to an increased microvessel density. Furthermore, hANG-transfected tumors show changes in expression of genes related to apoptosis, stress, signal transduction, and metabolism. CONCLUSION: hANG expression leads to inhibition of tumor growth, increased apoptosis, and changes in the expression of multiple genes involved in stress reactions, signal transduction, and apoptosis, which indicates a multifactorial reaction of tumors. An enhanced microvessel density is seen as part of these reactions and is associated with increased perfusion as measured by PET. 相似文献
9.
Heiko Sch?der Diane L Carlson Dennis H Kraus Hilda E Stambuk Mithat G?nen Yusuf E Erdi Henry W D Yeung Andrew G Huvos Jatin P Shah Steven M Larson Richard J Wong 《Journal of nuclear medicine》2006,47(5):755-762
(18)F-FDG PET has a high accuracy in staging head and neck cancer, but its role in patients with clinically and radiographically negative necks (N0) is less clear. In particular, the value of combined PET/CT has not been determined in this group of patients. METHODS: In a prospective study, 31 patients with oral cancer and no evidence of lymph node metastases by clinical examination or CT/MRI underwent (18)F-FDG PET/CT before elective neck dissection. PET/CT findings were recorded by neck side (left or right) and lymph node level. PET/CT findings were compared with histopathology of dissected nodes, which was the standard of reference. RESULTS: Elective neck dissections (26 unilateral, 5 bilateral; a total of 36 neck sides), involving 142 nodal levels, were performed. Only 13 of 765 dissected lymph nodes harbored metastases. Histopathology revealed nodal metastases in 9 of 36 neck sides and 9 of 142 nodal levels. PET was TP in 6 nodal levels (6 neck sides), false-negative in 3 levels (3 neck sides), true-negative in 127 levels (23 neck sides), and false-positive in 6 levels (4 neck sides). The 3 false-negative findings occurred in metastases smaller than 3 mm or because of inability to distinguish between primary tumor and adjacent metastasis. TP and false-positive nodes exhibited similar standardized uptakes (4.8 +/- 1.1 vs. 4.2 +/- 1.0; P = not significant). Sensitivity and specificity were 67% and 85% on the basis of neck sides and 67% and 95% on the basis of number of nodal levels, respectively. If a decision regarding the need for neck dissection had been based solely on PET/CT, 3 false-negative necks would have been undertreated, and 4 false-positive necks would have been overtreated. CONCLUSION: (18)F-FDG PET/CT can identify lymph node metastases in a segment of patients with oral cancer and N0 neck. A negative test can exclude metastatic deposits with high specificity. Despite reasonably high overall accuracy, however, the clinical application of PET/CT in the N0 neck may be limited by the combination of limited sensitivity for small metastatic deposits and a relatively high number of false-positive findings. The surgical management of the N0 neck should therefore not be based on PET/CT findings alone. 相似文献
10.
PD Dr. K. Ludwig 《Der Radiologe》2007,47(3):240-249
About 3–4% of all tumors and tumor-like lesions of the skeleton are located in the foot. Many of these lesions have a predilection for certain locations, so that the spectrum of entities occurring in the foot differs from the rest of the skeleton. Despite the fact that practically any entity can occur in the foot in rare cases, taken together the ten most frequent lesions make up for the vast majority of tumors and tumor-like lesions of the foot. The differential diagnosis of these lesions follows the general principles that apply in the rest of the skeleton. It is based on the analysis of the lesion’s X-ray morphology and location, the patient’s age, and in certain entities, the MR morphology. This article describes the most important tumors and tumor-like lesions of the foot, their differential diagnosis, and the principles of local staging. 相似文献