全文获取类型
收费全文 | 5954篇 |
免费 | 333篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 38篇 |
儿科学 | 217篇 |
妇产科学 | 158篇 |
基础医学 | 989篇 |
口腔科学 | 70篇 |
临床医学 | 383篇 |
内科学 | 1058篇 |
皮肤病学 | 185篇 |
神经病学 | 627篇 |
特种医学 | 182篇 |
外国民族医学 | 5篇 |
外科学 | 821篇 |
综合类 | 37篇 |
预防医学 | 275篇 |
眼科学 | 177篇 |
药学 | 427篇 |
中国医学 | 1篇 |
肿瘤学 | 661篇 |
出版年
2023年 | 36篇 |
2022年 | 73篇 |
2021年 | 86篇 |
2020年 | 65篇 |
2019年 | 78篇 |
2018年 | 100篇 |
2017年 | 78篇 |
2016年 | 111篇 |
2015年 | 127篇 |
2014年 | 163篇 |
2013年 | 202篇 |
2012年 | 269篇 |
2011年 | 302篇 |
2010年 | 156篇 |
2009年 | 169篇 |
2008年 | 294篇 |
2007年 | 244篇 |
2006年 | 268篇 |
2005年 | 285篇 |
2004年 | 245篇 |
2003年 | 256篇 |
2002年 | 214篇 |
2001年 | 229篇 |
2000年 | 209篇 |
1999年 | 182篇 |
1998年 | 79篇 |
1997年 | 68篇 |
1996年 | 57篇 |
1995年 | 32篇 |
1994年 | 49篇 |
1993年 | 36篇 |
1992年 | 103篇 |
1991年 | 89篇 |
1990年 | 84篇 |
1989年 | 78篇 |
1988年 | 90篇 |
1987年 | 82篇 |
1986年 | 71篇 |
1985年 | 56篇 |
1984年 | 45篇 |
1983年 | 39篇 |
1982年 | 32篇 |
1979年 | 52篇 |
1975年 | 31篇 |
1974年 | 41篇 |
1973年 | 36篇 |
1972年 | 33篇 |
1971年 | 32篇 |
1969年 | 30篇 |
1966年 | 46篇 |
排序方式: 共有6311条查询结果,搜索用时 15 毫秒
51.
Pregnancies during early adolescence were commonly thought to represent special risks, such as preterm delivery or low‐weight newborns, resulting in increased mortality and morbidity of mother and child. An important biopsychosocial interaction can be assumed. In the present study the impact of maternal age and maternal somatic characteristics such as prepregnancy weight, stature, or pregnancy weight gain on newborn somatometric features (birth weight, birth length, head circumference, and arcomial circumference) using a dataset of 8,011 single term births were analyzed. The offspring of 215 extremely young mothers ages 12–16 years were significantly (P < 0.0001) lighter and smaller in all body dimensions than the offspring of older adolescent mothers, ages 17–19 years, and the offspring of adult gravida, ages 20–29 years, although no increased incidence of low‐weight newborns (<2,500g) could be observed. As expected, the youngest mothers were also significantly smaller and lighter than their older, biologically more mature counterparts, although the relative weight gain during pregnancy was highest in the youngest age group (23.4% vs. 22.9 and 22.1%, respectively). In general, age but also pregnancy weight gain and prepregnancy weight status were significantly associated with pregnancy outcome. Within term births taking place under sufficient psychosocial support, maternal somatic features had an important impact on newborn size. Am. J. Hum. Biol. 15:220–228, 2003. ©2003 Wiley‐Liss, Inc. 相似文献
52.
The disintegrin/metalloprotease ADAM 10 is essential for Notch signalling but not for alpha-secretase activity in fibroblasts 总被引:14,自引:0,他引:14
Hartmann D de Strooper B Serneels L Craessaerts K Herreman A Annaert W Umans L Lübke T Lena Illert A von Figura K Saftig P 《Human molecular genetics》2002,11(21):2615-2624
The metalloprotease ADAM 10 is an important APP alpha-secretase candidate, but in vivo proof of this is lacking. Furthermore, invertebrate models point towards a key role of the ADAM 10 orthologues Kuzbanian and sup-17 in Notch signalling. In the mouse, this function is, however, currently attributed to ADAM 17/TACE, while the role of ADAM 10 remains unknown. We have created ADAM 10-deficient mice. They die at day 9.5 of embryogenesis with multiple defects of the developing central nervous system, somites, and cardiovascular system. In situ hybridization revealed a reduced expression of the Notch target gene hes-5 in the neural tube and an increased expression of the Notch ligand dll-1, supporting an important role for ADAM 10 in Notch signalling in the vertebrates as well. Since the early lethality precluded the establishment of primary neuronal cultures, APPs alpha generation was analyzed in embryonic fibroblasts and found to be preserved in 15 out of 17 independently generated ADAM 10-deficient fibroblast cell lines, albeit at a quantitatively more variable level than in controls, whereas a severe reduction was found in only two cases. The variability was not due to differences in genetic background or to variable expression of the alternative alpha-secretase candidates ADAM 9 and ADAM 17. These results indicate, therefore, either a regulation between ADAMs on the post-translational level or that other, not yet known, proteases are able to compensate for ADAM 10 deficiency. Thus, the observed variability, together with recent reports on tissue-specific expression patterns of ADAMs 9, 10 and 17, points to the existence of tissue-specific 'teams' of different proteases exerting alpha-secretase activity. 相似文献
53.
Comparison of a shiga toxin enzyme-linked immunosorbent assay and two types of PCR for detection of shiga toxin-producing Escherichia coli in human stool specimens 下载免费PDF全文
Pulz M Matussek A Monazahian M Tittel A Nikolic E Hartmann M Bellin T Buer J Gunzer F 《Journal of clinical microbiology》2003,41(10):4671-4675
Shiga toxin (Stx)-producing Escherichia coli (STEC) is a major cause of sporadic cases of disease as well as serious outbreaks worldwide. The spectrum of illnesses includes mild nonbloody diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome. STEC produces one or more Stxs, which are subdivided into two major classes, Stx1 and Stx2. The ingestion of contaminated food or water, person-to-person spread, and contact with animals are the major transmission modes. The infective dose of STEC may be less than 100 organisms. Effective prevention of infection is dependent on rapid detection of the causative bacterial pathogen. In the present study, we examined 295 stool specimens for the presence of Stx-producing E. coli by three different methods: an Stx enzyme-linked immunosorbent assay, a conventional PCR assay, and a LightCycler PCR (LC-PCR) assay protocol recently developed by our laboratory at the Institute of Medical Microbiology at Hannover Medical School. Our intent was to compare these three methods and to examine the utility of the STEC LC-PCR protocol in a clinical laboratory. The addition of a control DNA to each sample to clearly discriminate inhibited specimens from negative ones enhanced the accuracy of the LC-PCR protocol. From our results, it can be concluded that LC-PCR is a very useful tool for the rapid and safe detection of STEC in clinical samples. 相似文献
54.
The effects of the loop diuretics ethacrynic acid and bumetanide on lithium, bicarbonate and phosphate reabsorption were compared in 16 anaesthetized, normovolaemic dogs. In six dogs, ethacrynic acid (3 mg kg-1 body wt) significantly reduced absolute lithium reabsorption from 29.3 +/- 4.1 to 19.0 +/- 3.4 mumol min-1, fractional lithium reabsorption from 0.65 +/- 0.04 to 0.37 +/- 0.04 and fractional chloride reabsorption from 1.00 +/- 0.00 to 0.65 +/- 0.02. Bicarbonate and phosphate reabsorption did not decrease significantly. In six other dogs, bumetanide (30 micrograms kg-1 body wt) gave similar results. Absolute lithium reabsorption significantly decreased from 34.0 +/- 2.2 to 18.1 +/- 2.6 mumol min-1 and fractional lithium reabsorption decreased from 0.50 +/- 0.03 to 0.25 +/- 0.03. Fractional chloride reabsorption decreased from 0.98 +/- 0.00 to 0.61 +/- 0.05, whereas bicarbonate and phosphate reabsorption were not significantly altered. Thus, both loop diuretics greatly reduced lithium reabsorption. We propose that loop diuretics inhibit passive lithium reabsorption in the thick ascending limb of Henle's loop by reducing the lumen-positive electrical potential that drives passive cation transport. 相似文献
55.
56.
J Ostensen E S Stokke A Hartmann K Wensell F Kiil 《Acta physiologica Scandinavica》1989,137(2):189-198
To examine the oxygen requirement of carbonic anhydrase-dependent sodium reabsorption in the proximal tubule, 18 anaesthetized dogs were studied under conditions of saturated distal NaCl reabsorption; the latter was accomplished by volume expansion (all groups) combined with infusion of loop diuretics (groups 1 and 3). Acetazolamide reduced HCO3- reabsorption by 602 +/- 32 mumol min-1 (55%, group 1) and by 777 +/- 103 mumol min-1 (66%, group 2). This was accompanied with a reduction in sodium reabsorption and oxygen consumption in a molar delta Na/delta O2 ratio of about 45 in both groups of dogs. The delta HCO3/delta O2 ratio averaged 16 +/- 1, which was not significantly different from the theoretical value of 18 expected for transcellular sodium transport by Na+, K+-ATPase. Mannitol (group 3) reduced NaCl reabsorption by 37 +/- 2% without affecting NaHCO3 reabsorption or oxygen consumption significantly. We conclude that carbonic anhydrase-dependent NaCl reabsorption in the proximal tubules is passive, and that NaHCO3 reabsorption is the only important active sodium transport which is sensitive to inhibition of carbonic anhydrase. 相似文献
57.
Surgical management of hypoplastic right ventricle with pulmonary atresia or critical pulmonary stenosis and intact ventricular septum 总被引:2,自引:0,他引:2
Our experience with the surgical management of hypoplastic right ventricle with intact ventricular septum includes 26 patients with pulmonary atresia and 4 with critical pulmonary stenosis. Group 1 consisted of 8 neonates managed initially by transventricular valvotomy; 6 later required a secondary procedure, with 100% survival. Group 2 had 11 neonates managed by aorta-pulmonary artery shunting without operative death. However, only 3 have survived over the long term and 1 has required an additional shunt procedure. Group 3 had 9 infants who underwent concomitant valvotomy and shunting. There were 4 operative deaths and 1 late death. Finally, Group 4 included 2 infants managed by primary repair at 3 days and 6 days old with prosthetic enlargement of the right ventricle; 1 required the addition of a shunt. Both are alive. Seven of the 15 patients in Groups 1, 2, and 3 who survived neonatal palliative procedures have undergone reparative operations. Two had no growth of the right ventricle and underwent repair after conversion to tricuspid atresia, by a Fontan procedure. Five had prosthetic enlargement of the right ventricle in childhood with 1 late death. Findings of this review were as follows: (1) effective palliation of pulmonary atresia and intact ventricular septum or critical pulmonary stenosis with cavitary hypoplasia of the right ventricle is rare unless transventricular flow can be established; (2) establishment of transventricular flow produces a high incidence of cavitary "growth," which permits later repair; (3) the Fontan operation is available for repair in patients who have no cavitary growth; and (4) when all three portions of the right ventricular cavity can be identified by angiography, a primary repair can be performed in the neonatal period with a good long-term prognosis. 相似文献
58.
59.
Justin Gabriel Schlager Benjamin Kendziora Leilah Patzak Sophie Kupf Christoph Rothenberger Zeno Fiocco Lars E. French Markus Reinholz Daniela Hartmann 《International wound journal》2021,18(4):536
Recent studies showed that the COVID‐19 pandemic caused collateral damage in health care in terms of reduced hospital submissions or postponed treatment of other acute or chronic ill patients. An anonymous survey was sent out by mail to patients with chronic wounds in order to evaluate the impact of the pandemic on wound care. Sixty‐three patients returned the survey. In 14%, diagnostic workup or hospitalisation was cancelled or postponed. Thirty‐six percent could not seek consultation by their primary care physician as usual. The use of public transport or long travel time was not related to limited access to medical service (P = .583). In ambulatory care, there was neither a significant difference in the frequency of changing wound dressings (P = .67), nor in the person, who performed wound care (P = .39). There were no significant changes in wound‐specific quality of life (P = .505). No patient used telemedicine in order to avoid face‐to‐face contact or anticipate to pandemic‐related restrictions. The COVID‐19 pandemic impaired access to clinical management of chronic wounds in Germany. It had no significant impact on ambulatory care or wound‐related quality of life. Telemedicine still plays a negligible role in wound care. 相似文献
60.
Abbas Agaimy Robert Stoehr Lars Tgel Arndt Hartmann Thomas Cramer 《Head and neck pathology》2021,15(1):361
Porocarcinoma (synonym: malignant eccrine poroma) is a rare aggressive carcinoma type with terminal sweat gland duct differentiation. The squamous variant of porocarcinoma is even less frequent and might be indistinguishable from conventional squamous cell carcinoma (SCC). We herein describe the first case of a carcinoma presenting as a primary parotid gland malignancy in a 24-year-old male without any other primary tumor. Total parotidectomy and neck dissection were performed followed by adjuvant chemoradiation. The patient remained alive and well 10 months after diagnosis. Histology showed keratinizing SCC infiltrating extensively the parotid gland with subtle poroid cell features. Oncogenic HPV infection was excluded by DNA-based testing. NGS analysis using the TruSight RNA fusion panel (Illumina) revealed a novel YAP1-MAML2 gene fusion. This gene fusion was reported recently in a subset of cutaneous porocarcinoma and poroma. This case of poroid SCC (or squamoid porocarcinoma) adds to the differential diagnosis of SCC presenting as parotid gland tumor and highlights the value of molecular testing in cases with unusual presentation.Electronic supplementary materialThe online version of this article (10.1007/s12105-020-01181-9) contains supplementary material, which is available to authorized users. 相似文献