全文获取类型
收费全文 | 19414篇 |
免费 | 1170篇 |
国内免费 | 129篇 |
专业分类
耳鼻咽喉 | 197篇 |
儿科学 | 291篇 |
妇产科学 | 260篇 |
基础医学 | 2589篇 |
口腔科学 | 473篇 |
临床医学 | 1781篇 |
内科学 | 3927篇 |
皮肤病学 | 515篇 |
神经病学 | 2109篇 |
特种医学 | 1427篇 |
外科学 | 3566篇 |
综合类 | 125篇 |
一般理论 | 5篇 |
预防医学 | 640篇 |
眼科学 | 222篇 |
药学 | 1198篇 |
中国医学 | 13篇 |
肿瘤学 | 1375篇 |
出版年
2024年 | 11篇 |
2023年 | 172篇 |
2022年 | 271篇 |
2021年 | 507篇 |
2020年 | 345篇 |
2019年 | 450篇 |
2018年 | 520篇 |
2017年 | 430篇 |
2016年 | 519篇 |
2015年 | 650篇 |
2014年 | 791篇 |
2013年 | 886篇 |
2012年 | 1494篇 |
2011年 | 1591篇 |
2010年 | 993篇 |
2009年 | 922篇 |
2008年 | 1331篇 |
2007年 | 1362篇 |
2006年 | 1270篇 |
2005年 | 1195篇 |
2004年 | 1076篇 |
2003年 | 977篇 |
2002年 | 925篇 |
2001年 | 188篇 |
2000年 | 144篇 |
1999年 | 182篇 |
1998年 | 197篇 |
1997年 | 215篇 |
1996年 | 137篇 |
1995年 | 127篇 |
1994年 | 114篇 |
1993年 | 76篇 |
1992年 | 66篇 |
1991年 | 52篇 |
1990年 | 49篇 |
1989年 | 55篇 |
1988年 | 59篇 |
1987年 | 33篇 |
1986年 | 56篇 |
1985年 | 40篇 |
1984年 | 27篇 |
1983年 | 30篇 |
1982年 | 28篇 |
1981年 | 16篇 |
1980年 | 19篇 |
1979年 | 8篇 |
1978年 | 14篇 |
1977年 | 13篇 |
1976年 | 17篇 |
1975年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Anne F. Mannion Barbara R. Weber Jiri Dvorak Dieter Grob Markus Müntener 《Journal of orthopaedic research》1997,15(6):881-887
A knowledge of the alteration in the fibre type profile of paraspinal muscle associated with low back pain is essential for the design of successful rehabilitation programmes. In attempting to compare the muscles of patients with low back pain with those of controls, few previous studies have considered factors such as gender, age, and size of the subjects, each of which can potentially confound interpretation of the results. We obtained samples of lumbar paraspinal muscle during spinal surgery from 21 patients with low back pain and, using the percutaneous biopsy technique, from 21 control volunteers matched for gender, age, and body mass. The samples were subject to routine histochemicsl typcal analysis to determine characteristics of muscle fibre type. Compared with controls, the muscle of the patients had a significantly higher proportion of type-IIB (fast-twitch glycolytic) fibres than type- I (slow oxidatve) fibres. The mean size of a given fibre type did not differ between the patients and the controls. Consequently, the relative area of the muscle iccupied by type-IIB fibres was higher and that by type-I fibres Was lower in the patients. The patients had a greater number of muscle samples with more than 1% type-IIC fibres, and abnormalities that could be described as pathological were more marked in the patients than in the controls. In conclusion, the paraspinal muscles of patients who have low back pain display a more glycolytic (faster) profile; this can be expected to render them less resistant to fatigue. 相似文献
32.
Markus Dietlein Klemens Scheidhauer Eberhard Voth Peter Theissen Harald Schicha 《European journal of nuclear medicine and molecular imaging》1997,24(11):1342-1348
Metastases of differentiated thyroid cancer may show different uptake patterns for fluorine-18 fluorodeoxyglucose and [131I]NaI. FDG positron emission tomography (PET), iodine-131 whole-body scintigraphy (131I WBS) and magnetic resonance imaging were performed in 58 unselected patients, and spiral computed tomography (CT) of the
lung in 25 patients. Thirty-eight patients presented with papillary carcinomas, 15 patients with follicular carcinomas and
five patients with variants of follicular carcinoma. Primary tumour stage (pT) was pT1 in 3, pT2 in 19, pT3 in 11 and pT4
in 25 cases. For the detection of metastases, FDG PET was found to have a sensitivity of 50%, 131I WBS a sensitivity of 61%, and the two methods combined a sensitivity of 86%. When FDG PET was limited to patients with elevated
thyroglobulin (Tg) levels and negative 131I WBS, the sensitivity of this algorithm was 82%. Of the 21 patients with lymph node metastases, seven presented with FDG
uptake but no iodine uptake. In four of them, a second FDG hot spot appeared in a lymph node metastasis of normal size. Five
of the seven patients underwent surgery. None of the eight patients with pulmonary metastases smaller than 1 cm exhibited
FDG uptake, while five of them had iodine uptake. All had positive results on spiral CT. In conclusion, FDG PET cannot be
substituted for 131I WBS. If the Tg level is elevated and 131I WBS is negative, FDG PET can be used to detect lymph node metastases and complements anatomical imaging. A spiral CT of
the lung is useful to exclude pulmonary metastases before planning a dissection of iodine-negative lymph node metastases.
Received 2 May and in revised form 8 July 1997 相似文献
33.
Objective . To describe the importance of migraine in Santiago, Chile, by analyzing its prevalence, clinical features and impact by age, gender and socioeconomic status. Methods . In 1993, a representative sample of 1,540 adults of the province of Santiago were interviewed using a standard questionnaire. A total of 1,385 (89.9%) subjects responded to the survey. Initially, a designated member of each household responded to the questionnaire. Subsequently, each household member with headaches was asked to respond to questions about severity, frequency, location, duration, associated symptoms and impact in work and social activities of their most frequent headaches. Migraine diagnoses were determined in accordance with the International Headache Society (IHS) criteria of 1988. Results. Recurrent headaches in the past year were found in 516 (36.82%) respondents, 145 (28.1%) males and 371 (71.9%) females. Total prevalence of migraine was found to be 7.3% (95%, CI 5.9–8.6); 11.9% (95% CI 9.6–14.2) in females and 2.0% (95% CI 0.9–3.0) in males. Overall, migraine constituted 19.6% (101/516) of all headaches reported in this sample. The prevalence did not vary significantly by age groups or socioeconomic status (SES). Migraine with aura had an overall prevalence of 3.5% (CI 0.8–7.1), and was significantly more frequent in females. In 60–70% of cases the attacks lasted 2–6 h and the frequency was 3.3 and 3.4 per month in females and males respectively. Both males and females reported significantly high percentages of attacks during work. Conclusions . Migraine prevalence in a sample of adults of Santiago is similar to that reported in previous studies using IHS criteria. Women of all socioeconomic levels are at an increased risk. 相似文献
34.
Markus Kohler Hans M. Eppenberger Imogen Cordt-Riehle Christian Michel 《Acta oncologica (Stockholm, Sweden)》1992,31(6):673-677
Urination frequency and cystic pressure resistance have been used as end-points to assess x-ray-induced changes of bladder function. Whole or half bladders of adult male rabbits were irradiated, caudally or cranially. The absorbed dose was 33 Gy, 36 Gy or 39 Gy, given in 5 daily fractions. Animals which received a whole bladder dose of 39 Gy or 36 Gy showed increased urination frequency and enhanced bladder pressure resistance during the whole follow-up time of 100 weeks, compared with the sham-irradiated controls. At half bladder irradiation, only the highest doses (39 Gy to the cranial part of the bladder and 39 Gy or 36 Gy to the caudal part) gave rise to a slight increase in frequency at about 20 weeks after exposure. 相似文献
35.
Yuji Baba Markus M. Lerch David D. Stark Akihiro Tanimoto Burkhard P. Kreft Longhai Zhao Ashok K. Saluja Mutsumasa Takahashi 《Journal of magnetic resonance imaging : JMRI》1994,4(5):647-651
Previously unreported effects of tissue storage were recently observed in the authors' experimental magnetic resonance (MR) studies. To evaluate the effect of elapsed time after excision and storage temperature on tissue relaxation time measurements, tissue samples from the liver, pancreas, kidney, testis, spleen, and brain were obtained in rats. T1 and T2 were first measured within 5 minutes of excision, and between subsequent measurements, tubes were kept in a water bath at 40°C, at room temperature (28°C), or in an ice bath (4°C). Cellular and organellar integrity was assessed with electron microscopy and correlated with the MR findings. At 40°C (20-MHz spectrometer), the T1 of liver decreased from 280 msec ± 8 to 212 msec ± 10 during the first 60 minutes; the T1 of pancreas decreased from 276 msec ± 3 to 208 msec ± 2. Other tissues showed less than a 5% decrease in T1. T2 changes were smaller than T1 changes in all tissues. Electron microscopy of pancreatic acinar cells showed postmortem changes in mitochondria evolving over the first 60 minutes after death. Manganese loading experiments implicated mitochondrial manganese stores in the observed enhanced postmortem decrease in T1. This study calls into question reported relaxation time data for liver and pancreas. MR studies of excised tissues must account for time and temperature to prevent systematic experimental errors. 相似文献
36.
Markus Kohlhaas Olaf Stahlhut Joachim Tholuck Gisbert Richard 《Der Ophthalmologe : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft》1997,94(7):515-518
Ziel der vorliegenden Untersuchung war es, das Ausma? der Hornhautsch?digung durch eine Kataraktextraktion im Hinblick auf
das Hornhautendothel und die Hornhautdicke zu untersuchen.
Patienten und Methode: In einer prospektiven Untersuchung wurde die Entwicklung der Hornhautdicke und der Endothelzelldichte
an 48 Patienten untersucht. Die Patienten wurden mittels Phakoemulsifikation operiert. Die Hornhautdicke wurde dabei mit einem
Ultraschallpachymeter bei 12 Uhr und im Hornhautzentrum und die Endothelzelldichte mit einer Endothelzellkamera an den gleichen
Me?punkten pr?operativ sowie 4 Wochen, 4 Monate und 1 Jahr postoperativ bestimmt.
Ergebnisse: Ein Jahr postoperativ nahm die Hornhautdicke nach Phakoemulsifikation an der 12-Uhr-Position um ca. 9% und im
Hornhautzentrum um ca. 12% im Vergleich zum pr?operativen Wert zu. Die Endothelzelldichte war 1 Jahr postoperativ an der 12-Uhr-Position
um ca. 27% und im Zentrum um ca. 18% reduziert. Das Patientenalter korrelierte signifikant mit dem Zellverlust an beiden Me?punkten.
Bezüglich der Dickenzunahme ist keine signifikante Korrelation festzustellen.
Schlu?folgerung: Nach einer Kataraktextraktion ist der Hornhautstoffwechsel reduziert. Als Indikator k?nnen der Verlauf der
Endothelzelldichte und der Dicke herangezogen werden.
相似文献
37.
38.
Jan Groetzner Ingo Kaczmarek Bruno Meiser Markus Müller Sabine Daebritz Bruno Reichart 《The Journal of heart and lung transplantation》2004,23(6):770-773
Chronic renal failure triggered by calcineurin inhibitor (CNI)-based immunosuppression is a common complication after cardiac transplantation. Sirolimus and mycophenolate mofetil (MMF) are 2 newer immunosuppressive agents with no documented nephrotoxic side effects. This case report describes a patient with ongoing chronic renal failure 10 months after cardiac transplantation on cyclosporine-based immunosuppressive therapy. Conversion of the immunosuppressive regimen from cyclosporine to sirolimus and MMF resulted in freedom from acute rejection, excellent cardiac graft function and consistently improved renal function. This case illustrates the beneficial potential of sirolimus and MMF as CNI-free and safe long-term immunosuppression in a patient with chronic renal failure after heart transplantation. 相似文献
39.
Michael A Flierl Heike Schreiber Markus S Huber-Lang 《Journal of investigative surgery》2006,19(4):255-265
Sepsis continues to be a major clinical problem that is difficult to treat, as the pathophysiology of the disease is still unclear. Despite promising experimental strategies, therapeutic interventions have been largely unsuccessful. There is now increasing evidence that the disturbance of innate immunity during sepsis and multiorgan dysfunction syndrome (MODS) may be linked to uncontrolled activation of the complement system. Especially, the powerful anaphylatoxin C5a seems to play a key role in the development of immune paralysis. In this review, we describe our present understanding of the role of complement in the inflammatory response during sepsis and MODS. 相似文献
40.