全文获取类型
收费全文 | 24303篇 |
免费 | 1593篇 |
国内免费 | 136篇 |
专业分类
耳鼻咽喉 | 346篇 |
儿科学 | 606篇 |
妇产科学 | 457篇 |
基础医学 | 3894篇 |
口腔科学 | 403篇 |
临床医学 | 2324篇 |
内科学 | 5610篇 |
皮肤病学 | 500篇 |
神经病学 | 2240篇 |
特种医学 | 1081篇 |
外国民族医学 | 3篇 |
外科学 | 3288篇 |
综合类 | 176篇 |
现状与发展 | 1篇 |
一般理论 | 13篇 |
预防医学 | 1525篇 |
眼科学 | 172篇 |
药学 | 1623篇 |
中国医学 | 32篇 |
肿瘤学 | 1738篇 |
出版年
2023年 | 95篇 |
2022年 | 222篇 |
2021年 | 485篇 |
2020年 | 276篇 |
2019年 | 441篇 |
2018年 | 525篇 |
2017年 | 389篇 |
2016年 | 498篇 |
2015年 | 603篇 |
2014年 | 780篇 |
2013年 | 1033篇 |
2012年 | 1709篇 |
2011年 | 1796篇 |
2010年 | 988篇 |
2009年 | 977篇 |
2008年 | 1637篇 |
2007年 | 1745篇 |
2006年 | 1649篇 |
2005年 | 1734篇 |
2004年 | 1656篇 |
2003年 | 1577篇 |
2002年 | 1452篇 |
2001年 | 240篇 |
2000年 | 161篇 |
1999年 | 275篇 |
1998年 | 324篇 |
1997年 | 293篇 |
1996年 | 214篇 |
1995年 | 209篇 |
1994年 | 175篇 |
1993年 | 177篇 |
1992年 | 120篇 |
1991年 | 116篇 |
1990年 | 99篇 |
1989年 | 108篇 |
1988年 | 80篇 |
1987年 | 89篇 |
1986年 | 88篇 |
1985年 | 55篇 |
1984年 | 80篇 |
1983年 | 76篇 |
1982年 | 88篇 |
1981年 | 78篇 |
1980年 | 86篇 |
1979年 | 55篇 |
1978年 | 42篇 |
1977年 | 43篇 |
1975年 | 43篇 |
1974年 | 36篇 |
1972年 | 32篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
82.
83.
Klaus-Dietrich Wolff Sami Swaid Dirk Nolte Roland A B?ckmann Frank H?lzle Christian Müller-Mai 《Journal of cranio-maxillo-facial surgery》2004,32(2):71-79
BACKGROUND: A carbonated apatite cement (NORIAN SRS) was used as a bone mineral substitute for the calvaria or viscerocranium in 27 patients. It has the consistency of a paste and hardens at physiologic pH and body temperature due to dahllite crystallization, which has the stoichiometric formula Ca(8.8)(HPO(4))(0.7)(PO(4))(4.5)(CO(3))(0.7)(OH)(1.3). MATERIAL AND METHODS: The cement was used for posttraumatic bone defects in the orbital, periorbital or malar regions (nine patients), posttraumatic deformities of the frontal bone (six patients), tumour-dependent bony defects of the calvaria (two patients) and posttraumatic or cystic defects of the mandible (five patients). In another five patients, the material was used to augment the atrophic anterior mandible in combination with the insertion of dental implants. Follow-up varied between 6 and 40 months (mean: 29 months). RESULTS: There was no inflammatory reaction surrounding the implanted material. There was no sign of infection in any of the patients and only one case of partial wound dehiscence with superficially exposed material. The defect fillings and augmentations were successful in all patients. None of the 19 dental implants which were inserted in combination with the material showed any sign of infection or loosening. Also, there was no loosening of the implants after loading (mean follow-up: 15 months). From the check-up radiographs, the material could be seen as a dense, radio-opaque structure. There were no material fractures or dislocations. Radiologically, the material seemed to be completely replaced by bony tissue after 30 months. CONCLUSION: Our 5-year clinical experience suggests that the material is a suitable bone mineral substitute for cranio-maxillofacial surgery especially for moderate-sized defects of the calvaria and forehead bone. It has advantages over preformed, solid bone substitute materials, and, due to its initial plasticity and eventual great compressive strength, it can also stabilize dental endosseous implants in the atrophic mandible. 相似文献
84.
Olivier Chataigner Elie Fadel Bedrettin Yildizeli Abdallah Achir Sacha Mussot Dominique Fabre Olaf Mercier Philippe G. Dartevelle 《European journal of cardio-thoracic surgery》2008,33(5):837-843
Objective: To identify factors that affect operative mortality and morbidity and long-term survival after completion pneumonectomy. Methods: We retrospectively reviewed the charts of consecutive patients who underwent completion pneumonectomy at our cardiothoracic surgery department from January 1996 to December 2005. Results: We identified 69 patients, who accounted for 17.8% of all pneumonectomies during the study period; 22 had benign disease and 47 malignant disease (second primary lung cancer, n = 19; local recurrence, n = 17; or metastasis, n = 11). There were 50 males and 19 females with a mean age of 60 years (range, 29–80 years). Postoperative mortality was 12% and postoperative morbidity 41%. Factors associated with postoperative mortality included obesity (p = 0.005), coronary artery disease (p = 0.03), removal of the right lung (p = 0.02), advanced age (p = 0.02), and renal failure (p < 0.0001). Preoperative renal failure was the only significant risk factor for mortality by multivariate analysis (p = 0.036). Bronchopleural fistula developed in seven patients (10%), with risk factors being removal of the right lung (p = 0.04) and mechanical stump closure (p = 0.03). Overall survival was 65% after 3 years and 46% after 5 years. Long-term survival was not affected by the reason for completion pneumonectomy. Conclusion: Although long-term survival was acceptable, postoperative mortality and morbidity rates remained high, confirming the reputation of completion pneumonectomy as a challenging procedure. Significant comorbidities and removal of the right lung were the main risk factors for postoperative mortality. Improved patient selection and better management of preoperative renal failure may improve the postoperative outcomes of this procedure, which offers a chance for prolonged survival. 相似文献
85.
Erkki Lotspeich Markus Schoene Heinz Gerngroß Roland Schmidt Reinhard Steinmann Marco Ramadani Susanne Gansauge 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2007,392(5):559-566
Introduction Postoperative treatment for colorectal cancer depends on tumor stage as defined by the International Union Against Cancer
(UICC). Adjuvant chemotherapy is not recommended in patients without lymph node involvement (UICC stages I and II). As many
as 20–30% of these patients, however, will develop recurrence.
Aims and objectives We conducted this study to determine the presence of disseminated tumor cells in the lymph nodes by quantitative real-time
polymerase chain reaction (QRT-PCR) for cytokeratin 20 (CK20) in an attempt to provide supplementary information compared
to histopathological findings.
Materials and methods Using a standard QRT-PCR assay, we examined primary tumors and 391 lymph nodes from 31 patients with completely resected colorectal
cancer.
Results Of the 31 primary tumors, 29 were positive for CK20 by QRT-PCR.
Discussion An examination of the lymph nodes from the 29 patients with CK20-positive primary tumors revealed that 35 (92.1% sensitivity)
of the 38 histopathologically positive lymph nodes and 54 (16.7%) of the 324 histopathologically negative lymph nodes were
positive by molecular analysis. CK20 expression was detected in 10 (100%) of 10 patients with a histopathologically positive
lymph node status (pN1). In 9 (47.4%) of 19 patients with negative histopathological results (pN0), we detected a CK20 mRNA
signal in at least one lymph node. Whereas eight patients with histopathologically negative lymph nodes could be upstaged
on the basis of the molecular findings, no patient would be downstaged.
Conclusion Our results suggest that QRT-PCR for CK20 is a useful tool for the quantitative detection of micrometastases in the regional
lymph nodes. We introduce a standardized procedure that integrates a molecular diagnostic technique in the clinical staging. 相似文献
86.
Patrick Ambrosetti Karim Francis Dominique Weintraub Jonathan Weintraub 《Journal of gastrointestinal surgery》2007,11(6):767-772
We performed a prospective study to analyze the functional results following elective laparoscopic sigmoidectomy for computed
tomography (CT)-proven diagnosis of acute diverticulitis and review the literature. Forty-three of 45 available patients (96%)
who had laparoscopic sigmoidectomy for CT-proven acute diverticulitis answered, after a mean time of 40 months, a questionnaire
exploring new abdominal symptoms, bowel function, and the patient’s own judgement of the surgical outcome. Surgical technique
aimed at removing all the sigmoid by taking down the splenic flexure and do a colorectal anastomosis. Four patients (9%) complained
of new abdominal pain. Bowel function was reported as better for 24 patients (56%), unchanged for 16 patients (37%), and worse
for 3 (7%). Twenty patients (47%) considered their final result as excellent to good, 17 patients (40%) as satisfying, and
6 patients (13%) as mediocre. Male gender, absence of preoperative history compatible with an irritable bowel syndrome, length
of resected sigmoid and residual acute inflammation on histology are statistically predictive of a better postoperative degree
of satisfaction. After elective laparoscopic sigmoidectomy for CT-proven diverticulitis, a great majority of patients are
very satisfied with their postoperative general comfort. 相似文献
87.
Although the concept of receiving MR signal using multiple coils simultaneously has been known for over two decades, the technique has only recently become clinically available as a result of the development of several effective parallel imaging reconstruction algorithms. Despite the success of these algorithms, it remains a challenge in many applications to rapidly and reliably reconstruct an image from partially-acquired general non-Cartesian k-space data. Such applications include, for example, three-dimensional (3D) imaging, functional MRI (fMRI), perfusion-weighted imaging, and diffusion tensor imaging (DTI), in which a large number of images have to be reconstructed. In this work, a systematic k-space-based reconstruction algorithm based on k-space sparse matrices (kSPA) is introduced. This algorithm formulates the image reconstruction problem as a system of sparse linear equations in k-space. The inversion of this system of equations is achieved by computing a sparse approximate inverse matrix. The algorithm is demonstrated using both simulated and in vivo data, and the resulting image quality is comparable to that of the iterative sensitivity encoding (SENSE) algorithm. The kSPA algorithm is noniterative and the computed sparse approximate inverse can be applied repetitively to reconstruct all subsequent images. This algorithm, therefore, is particularly suitable for the aforementioned applications. 相似文献
88.
Stéphane Aubert Roland Henaine Olivier Raisky Nicolas Chavanis Jacques Robin René Ecochard Jean Ninet 《European journal of cardio-thoracic surgery》2005,28(2):223-228
OBJECTIVE: We consider the short- and long-term outcomes of the repair of the isolated partial atrioventricular (AV) septal defect to determine the role played by the atypical forms on the initial AV valve replacement and on the risk of reoperation. METHODS: Two hundred and eight patients underwent an operation for this malformation between 1974 and 2001. Clinical and echocardiographic examinations were performed on all patients, the AV valve regurgitation was graded from 1 to 4 and a residual interatrial shunt was sought. Median age at the intervention was 5.8 years (3 months to 67 years). RESULTS: Median follow-up time was 7.5 years (range 0-22.6 years). The cumulative 30-day, 5- and 20-year survival rates were 96.5, 95.4 and 94.6%, respectively. AV valve replacement was associated with a high mortality (P<0.001). A reoperation was performed on 12 patients (5.7%) including six patients within less than a 30-day period, especially to repair residual AV valve regurgitation. We performed four AV valve repairs by annuloplasty and six AV valve replacements. Two patients who had initially undergone an AV valve replacement underwent a reoperation for valve thrombosis. The cumulative 30-day, 5- and 20-year rates of freedom from reoperation were 96.5, 93.6 and 83%, respectively. An atypical form was present in 24 patients (11.5%) and was a risk factor for initial AV valve replacement (P<0.001) and for reoperation (P<0.001). A complete AV block occurred in 13 patients (6.2%), all of them within a 30-day period. The AV valve replacement was a high risk factor for a complete AV block (P<0.001). At the end of our study 180 patients (96%) were in NYHA I and 8 in NYHA II. CONCLUSIONS: The morbi-mortality of the isolated partial AV septal defect is primarily perioperative and is linked with the presence of an atypical form of the lesion. This atypical form was the main reason for reoperation for AV valve regurgitation. The AV valve replacement was associated with a high mortality and with the occurrence of complete AV block. Using a standardized technique, the AV septal defect can be repaired with excellent long-term clinical and echographic results. 相似文献
89.
Reed Jon A.; Nador Roland G.; Spaulding David; Tani Yoichi; Cesarman Ethel; Knowles Daniel M. 《Blood》1998,91(10):3825-3832