全文获取类型
收费全文 | 2949篇 |
免费 | 195篇 |
国内免费 | 26篇 |
专业分类
耳鼻咽喉 | 116篇 |
儿科学 | 109篇 |
妇产科学 | 128篇 |
基础医学 | 294篇 |
口腔科学 | 127篇 |
临床医学 | 267篇 |
内科学 | 673篇 |
皮肤病学 | 74篇 |
神经病学 | 112篇 |
特种医学 | 200篇 |
外科学 | 685篇 |
综合类 | 62篇 |
一般理论 | 2篇 |
预防医学 | 71篇 |
眼科学 | 69篇 |
药学 | 89篇 |
中国医学 | 6篇 |
肿瘤学 | 86篇 |
出版年
2023年 | 15篇 |
2022年 | 23篇 |
2021年 | 78篇 |
2020年 | 29篇 |
2019年 | 49篇 |
2018年 | 65篇 |
2017年 | 45篇 |
2016年 | 83篇 |
2015年 | 102篇 |
2014年 | 126篇 |
2013年 | 158篇 |
2012年 | 191篇 |
2011年 | 177篇 |
2010年 | 115篇 |
2009年 | 118篇 |
2008年 | 209篇 |
2007年 | 214篇 |
2006年 | 185篇 |
2005年 | 170篇 |
2004年 | 156篇 |
2003年 | 119篇 |
2002年 | 103篇 |
2001年 | 39篇 |
2000年 | 58篇 |
1999年 | 40篇 |
1998年 | 25篇 |
1997年 | 39篇 |
1996年 | 32篇 |
1995年 | 27篇 |
1994年 | 16篇 |
1993年 | 12篇 |
1992年 | 25篇 |
1991年 | 21篇 |
1990年 | 15篇 |
1989年 | 17篇 |
1988年 | 16篇 |
1987年 | 20篇 |
1986年 | 18篇 |
1985年 | 33篇 |
1984年 | 21篇 |
1983年 | 18篇 |
1981年 | 18篇 |
1980年 | 11篇 |
1979年 | 14篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1975年 | 11篇 |
1973年 | 12篇 |
1970年 | 7篇 |
1969年 | 10篇 |
排序方式: 共有3170条查询结果,搜索用时 15 毫秒
1.
2.
Mine G. Güllüoğlu Zeki Kılıçaslan Alper Toker Göksel Kalaycı Dilek Yılmazbayhan 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2006,391(3):222-227
Background and aims The aim of this study was to assess the diagnostic value of image guided percutaneous fine needle aspiration (FNA) biopsy in equivocal mediastinal masses.Patients Sixty-six patients with an equivocal mediastinal mass who underwent FNA biopsy between 1993 and 2003 were eligible for final analysis. The cytological and definitive diagnosis of masses were grouped as primary 22 (33%)−30 (46%) and secondary (metastatic) neoplasms 18 (27%)−18 (27%) and nonneoplastic lesions 20 (30%)−18 (%27) respectively.Results The diagnostic accuracy (%95 C.I.) of FNA biopsy for primary mediastinal neoplasms, secondary neoplasms and nonneoplastic lesions were found to be 93.3 (83.8–98.2)%, 100 (95.1–100)%, 93.3 (83.8–98.2)%, respectively.Conclusion Image guided percutaneous FNA biopsy is a safe and highly accurate diagnostic method for equivocal mediastinal masses. 相似文献
3.
Chairat Shayakul Petr Jarolim Marie Zachlederova Daniel Prabakaran Dionisio Cortez-Campeao Dana Kalabova Alan K Stuart-Tilley Hiroshi Ideguchi Christlieb Haller Seth L Alper 《Nephrology, dialysis, transplantation》2004,19(2):371-379
BACKGROUND: Mutations in the human SLC4A1 (AE1/band 3) gene are associated with hereditary spherocytic anaemia and with distal renal tubular acidosis (dRTA). The molecular diagnosis of AE1 mutations has been complicated by the absence of highly polymorphic genetic markers, and the pathogenic mechanisms of some dRTA-associated AE1 mutations remain unclear. Here, we characterized a polymorphic dinucleotide repeat close to the human AE1 gene and performed an immunocytochemical study of kidney tissue from a patient with inherited dRTA with a defined AE1 mutation. METHODS: One CA repeat region was identified in a phage P1-derived artificial chromosome (PAC) clone containing most of the human AE1 gene and the upstream flanking region. We determined its heterozygosity value in multiple populations by PCR analysis. Genotyping of one family with dominant dRTA identified the AE1 R589H mutation, and family member genotypes were compared with the CA repeat length. AE1 and vH(+)-ATPase polypeptides in kidney tissue from an AE1 R589H patient were examined by immunocytochemistry for the first time. RESULTS: This CA repeat, previously reported as D17S1183, is approximately 90 kb upstream of the AE1 gene and displayed considerable length polymorphism, with small racial differences, and a heterozygosity value of 0.56. The allele-specific length of this repeat confirmed co-segregation of the AE1 R589H mutation with the disease phenotype in a family with dominant dRTA. Immunostaining of the kidney cortex from one affected member with superimposed chronic pyelonephritis revealed vH(+)-ATPase-positive intercalated cells in which AE1 was undetectable, and proximal tubular epithelial cells with apparently enhanced apical vH(+)-ATPase staining. CONCLUSIONS: The highly polymorphic dinucleotide repeat adjacent to the human AE1 gene may be useful for future studies of disease association and haplotype analysis. Intercalated cells persist in the end-stage kidney of a patient with familial autosomal dominant dRTA associated with the AE1 R589H mutation. The absence of detectable AE1 polypeptide in those intercalated cells supports the genetic prediction that the AE1 R589H mutation indeed causes dominant dRTA. 相似文献
4.
Joseph C. Alper M.D. Elizabeth A. Welch M.D. Patricia Maguire R.N. 《Age (Dordrecht, Netherlands)》1986,9(4):105-109
During a five year period, approximately 150 elderly patients were treated with a water vapor and oxygen permeable membrane
(VPM) in an open fashion.
The following is important when treating elderly patients with VPM: xerosis or irritant dermatitis must be thoroughly treated
before use of VPM as it will not adhere to abnormal skin; alcohol or acetone should not be used to prepare the treatment site
as they cause irritation; VPM must not be stretched prior to placement as friction blisters occur in fragile, elderly skin;
prior to removal, VPM should be soaked in soapy water or its surface rubbed lightly with alconol to break the adhesive bond
to prevent stripping off epidermis; in patients with protein-calorie malnutrition, serum albumin should be monitored as large
amounts of protein-rich fluid collect under VPM. VPM is a useful non-surgical approach to treating many ulcers in the elderly.
Certain precautions must be taken to achieve optimum success in this population. 相似文献
5.
Otavio B Piltcher J Douglas Swarts Karin Magnuson Cuneyt M Alper William J Doyle Patricia A Hebda 《Otolaryngology--head and neck surgery》2002,126(5):490-498
OBJECTIVE: To describe the clinical and histopathologic progression of a rat model of otitis media with effusion caused by eustachian tube obstruction (ETO) with and without Streptococcus pneumoniae infection. METHODS: In 164 rats, the left, bony eustachian tube was approached via a ventral incision and obstructed with dental material. Then 108 rats were infected via an intrabullar injection with S pneumoniae. At 48 hours, the infected rats were treated for 5 days with ampicillin. All ears were evaluated by weekly otomicroscopy. On each of days 1, 2, 7, 21, 35, 56, and 112, four rats were killed for histologic study. All effusions were cultured for bacteria. RESULTS: Fourteen rats died of surgical complications; effusion resolved by 2 weeks in 9 rats. During the first few days, infected ears with ETO had bulging tympanic membranes, followed by tympanic membrane retraction, purulent effusion, and otorrhea (50%) over the next few weeks, whereas uninfected ears with ETO developed retraction and serous effusion during the same time frame. At later times, all ears with ETO presented with retraction and serous or serous-mucoid effusion. S pneumoniae was recovered only from the infected ears with ETO (days 1 and 2), with some colonization by nonpathogenic microorganisms observed equally in both groups of ears. Histology showed a typical acute inflammatory reaction in the challenged ears with ETO through day 14 and then a chronic inflammation for all ears with ETO. CONCLUSION: The experimental methods provoked reproducible pathologic signs similar to those for otitis media with effusion. Given the availability of rat-specific reagents, this model is well suited for studies of cytokine elaboration during disease pathogenesis. 相似文献
6.
Alper Alkan Erdal Erdem Omer Günhan Cimen Karasu 《Journal of oral and maxillofacial surgery》2002,60(8):898-904
PURPOSE: Bone healing is impaired in diabetes mellitus, particularly due to increased collagen breakdown. Recently, tetracyclines have been used to treat experimental bone defects because they have anticollagenolytic properties, and positive effects on the healing process have been obtained. The objective of this study was to develop a computer-assisted histomorphometric technique to quantitatively determine the amount of regenerating bone within experimental bone defects in a diabetic rodent model. MATERIALS AND METHODS: This study examined the effects of systemic doxycycline administration on the healing of tibial bone defects in healthy albino rats and in experimentally induced diabetic rats. Twenty-four female albino rats were assigned to 4 groups: diabetic, diabetic plus doxycycline, control, or control plus doxycycline. The standardized bone defects were histomorphometrically examined 10 and 30 days postoperatively. Histomorphometric analysis of the amount of new bone formation was performed using the Zeiss Vision image analysis program KS 400 (Kontron Elektron GmbH, Eching, Germany). RESULTS: At 10 days of healing, the diabetic groups exhibited inferior healing compared with the control groups in terms of the amount of new bone formation within the defects. However, the effect of doxycycline administration to the diabetic and control groups was not statistically different. At 30 days of healing, there were no statistically significant differences between the amount of newly formed bone in any of the groups. CONCLUSIONS: This study found that doxycycline administration did not significantly alter the amount of new bone formation during the healing of bone defects in control and diabetic rats. 相似文献
7.
Calciphylaxis – a topical overview 总被引:3,自引:0,他引:3
G Arseculeratne† AT Evans‡ SM Morley† 《Journal of the European Academy of Dermatology and Venereology》2006,20(5):493-502
'Calciphylaxis', a calcification syndrome associated with ischaemic cutaneous necrosis, is acquired naturally in humans in disease states. It is a life and limb-threatening complication, usually observed in patients with renal disease and secondary hyperparathyroidism, but known to occur in the absence of renal or parathyroid disease. The reported mortality rate, which ranges from 60-80%, relates to wound infection, sepsis and organ failure. It is a small-vessel vasculopathy, which is estimated to occur in about 4% of haemodialysis patients. Clinically, violaceous, reticulate areas of cutaneous necrosis and eschar may be evident, particularly in the extremities. In addition to the clinical picture, a raised calcium phosphorous product, an elevated parathyroid hormone level, radiographic evidence of vessel and soft-tissue calcification and the finding of mural calcification affecting small arteries and arterioles on histopathology help to confirm the diagnosis of this entity which generally has a poor prognosis. A high index of suspicion and an active multidisciplinary management approach, with rigorous attention to wound care and prevention of sepsis, are vital in the management of these patients. In this overview, we discuss the pathophysiology, clinical features and associations, risk factors, diagnosis and management issues relating to calciphylaxis. 相似文献
8.
9.
William J Doyle Cuneyt M Alper Juliane M Banks J Douglas Swarts 《Otolaryngology--head and neck surgery》2003,128(5):732-741
OBJECTIVES: We tested the hypothesis that mastoid volume buffers the rate of change in middle ear pressure caused by transmucosal, inert gas exchange. STUDY DESIGN: Twelve monkeys were randomly assigned to group 1 or group 2. Right ears of group 1 had sham surgery and of group 2 had obstruction of the mastoid antrum. Before and after surgery, the time constant for transmucosal N(2)O exchange was estimated from N(2)O breathing experiments. The hypothesis predicts that the postoperative time constant measured for right ears of group 2 but not group 1 is greater than that measured before surgery. RESULTS: Mastoid antrum block significantly decreased right middle ear volume but did not affect the time constant for transmucosal N(2)O exchange. CONCLUSION: A mastoid gas-reserve function is not supported by the experimental data. SIGNIFICANCE: These results for monkeys and the theory developed to explain the effect of mastoid volume on transmucosal inert gas exchange suggest that the results for previous experiments in humans interpreted as evidencing a mastoid gas-reserve function are consistent with alternative explanations. 相似文献
10.