全文获取类型
收费全文 | 245890篇 |
免费 | 5375篇 |
国内免费 | 271篇 |
专业分类
耳鼻咽喉 | 2325篇 |
儿科学 | 8588篇 |
妇产科学 | 4452篇 |
基础医学 | 24386篇 |
口腔科学 | 3045篇 |
临床医学 | 19354篇 |
内科学 | 45276篇 |
皮肤病学 | 1764篇 |
神经病学 | 23284篇 |
特种医学 | 11415篇 |
外国民族医学 | 5篇 |
外科学 | 40963篇 |
综合类 | 3150篇 |
一般理论 | 95篇 |
预防医学 | 23893篇 |
眼科学 | 4100篇 |
药学 | 14004篇 |
中国医学 | 734篇 |
肿瘤学 | 20703篇 |
出版年
2023年 | 400篇 |
2022年 | 664篇 |
2021年 | 1806篇 |
2020年 | 947篇 |
2019年 | 1592篇 |
2018年 | 23470篇 |
2017年 | 18489篇 |
2016年 | 20653篇 |
2015年 | 2383篇 |
2014年 | 3056篇 |
2013年 | 3986篇 |
2012年 | 11743篇 |
2011年 | 25775篇 |
2010年 | 21321篇 |
2009年 | 13869篇 |
2008年 | 23747篇 |
2007年 | 26209篇 |
2006年 | 5119篇 |
2005年 | 6684篇 |
2004年 | 7630篇 |
2003年 | 8245篇 |
2002年 | 6148篇 |
2001年 | 899篇 |
2000年 | 960篇 |
1999年 | 843篇 |
1998年 | 967篇 |
1997年 | 887篇 |
1996年 | 700篇 |
1995年 | 630篇 |
1994年 | 615篇 |
1993年 | 500篇 |
1992年 | 451篇 |
1991年 | 485篇 |
1990年 | 466篇 |
1989年 | 395篇 |
1988年 | 367篇 |
1987年 | 342篇 |
1986年 | 335篇 |
1985年 | 435篇 |
1984年 | 489篇 |
1983年 | 405篇 |
1982年 | 578篇 |
1981年 | 512篇 |
1980年 | 512篇 |
1979年 | 235篇 |
1978年 | 311篇 |
1977年 | 294篇 |
1976年 | 234篇 |
1975年 | 262篇 |
1974年 | 217篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Miller PD 《Current osteoporosis reports》2004,2(2):59-64
Bone mineral density (BMD) measurements have been the single greatest advancement for osteoporosis. BMD measurements have
helped define a prefracture diagnosis of osteoporosis, predict fracture risk in postmenopausal women and elderly men, and
monitor the course of disease processes that negatively affect bone or therapeutic agents that can improve bone strength.
Despite the large amount of clinical, epidemiologic, and basic science data that has advanced our understanding of BMD performance
and interpretation, many pitfalls in BMD performance and interpretation pervade the practice of bone densitometry. However,
all of these pitfalls can be overcome. Proper quality control and clinical interpretation of BMD computer printout reports
are paramount for correct diagnosis, risk assessment, and serial BMD measurements. Though BMD application(s) are a clinical
tool that can and should be used by many different primary care and specialty physicians, the performances and interpretations
are not simple processes. Proper education and training in the use of BMD technologies provides the means of achieving the
great intent that BMD measurements are capable of providing. 相似文献
992.
Purpose. Age is known to be a major risk factor for adverse postoperative cognitive dysfunction after cardiac surgery. We conducted this study to determine if jugular venous oxygen saturation (SjvO2) differed during mild hypothermic (32°C) and normothermic cardiopulmonary bypass (CPB) in elderly patients.Methods. Sixty patients aged over 70 years who underwent elective coronary artery bypass grafting were randomly divided into two groups. Group 1 (n = 30) underwent normothermic CPB (>35°C) and group 2 (n = 30) underwent mild hypothermic CPB (32°C). For the continuous monitoring of SjvO2, a fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb after the induction of anesthesia. Hemodynamic parameters, and arterial and jugular venous blood gases were measured at seven time points.Results. The SjvO2 in the normothermic group was lower at the onset of CPB and 20min after the onset, than from the time of induction of anesthesia until the start of surgery (period 1), the respective SjvO2 values being 50.3% ± 1.0%, 50.1% ± 1.6%, and 59.5% ± 1.9% (P < 0.05). However, in the mild hypothermic group there were no changes in the SjvO2 value throughout the study. The cerebral desaturation time (when the SjvO2 value was <50%) and the ratio of the cerebral desaturation time to the total CPB time in the normothermic group differed significantly from those in the hypothermic group, being 19 ± 11min and 17% ± 10%, and 9 ± 3min and 8% ± 4%, respectively (P < 0.05).Conclusions. The SjvO2 value was better during mild hypothermic CPB than during normothermic CPB in elderly patients. 相似文献
993.
Transfemoral approach and cementless distally locked stem in total hip replacement failures 总被引:1,自引:0,他引:1
Charles Picault 《Journal of orthopaedic science》2004,9(2):191-207
994.
Prostate-specific antigen and related isoforms in the diagnosis and management of prostate cancer 总被引:1,自引:0,他引:1
Despite its unparalleled merits for prostate cancer detection and staging, prostate-specific antigen (PSA) is not a marker
for prostate cancer only, but also is expressed in benign conditions. For early detection, limitations of PSA are obvious.
Its widespread use has led to an extensive amount of expensive and often unnecessary diagnostic procedures associated with
significant morbidity. Total PSA derivatives may enhance the accuracy of prostate cancer diagnosis. The ratio of free-to-total
PSA improves specificity while maintaining a high sensitivity for prostate cancer detection for men with a total PSA of 2.5
to 10 ng/mL. Human glandular kallikrein also has the potential to be a valuable tool in combination with total and free PSA
for early diagnosis of prostate cancer. Complex PSA seems to be a reliable tool to improve specificity at high sensitivity
levels in men with suspected prostate cancer (mainly in PSA levels below 4 ng/mL). Newly discovered isoforms of free PSA also
may impact early detection of prostate cancer with encouraging preliminary results that warrant further clinical investigation. 相似文献
995.
David?S.?ZingmondEmail author L.?Joseph?MeltonIII Stuart?L.?Silverman 《Osteoporosis international》2004,15(8):603-610
Background: Hip fracture incidence in non-Hispanic whites (NHW) has decreased nationwide for the past 20 years. Little is known regarding hip fracture incidence among Hispanics, the largest, fastest growing minority in the United States. Objective: To assess the change in standardized hip fracture incidence from 1983 through 2000 in California Hispanics relative to other racial groups. Design: Hospitalizations for individuals older than 55 years with hip fracture requiring repair in acute care hospitals. Annual population estimates based on US Census Bureau estimates. Incidence standardized to national gender-age strata. Change in annual incidence calculated by weighted linear regression with robust variance estimates. Results: 372,078 hip fractures were identified. Age-adjusted annual incidence of hip fractures declined by 0.74% per year among women (655 to 568 per 100,000), but was unchanged among men (247 to 238 per 100,000). Among NHW women, the standardized annual incidence fell by 0.6% (4.0 fractures per 100,000) per year. Annual incidence among Hispanic women increased 4.9% (11.1 fractures per 100,000) per year. Annual incidence among Hispanic men increased by 4.2% (4.5 fractures per 100,000) per year and among NHW men by 0.5% (1.2 fractures per 100,000) per year. No significant change occurred among black or Asian women or men. Conclusions: Among California women, hip fracture incidence has doubled among Hispanics since 1983, while remaining unchanged or declining in other groups. Greater attention should be given to identification of individuals at risk for hip fracture and initiation of preventive measures in Hispanic populations. 相似文献
996.
Contemporary management of penile cancer including surgery and adjuvant radiotherapy: an experience in Taiwan 总被引:1,自引:0,他引:1
This retrospective study reports on the treatment outcomes of 45 men with penile cancer and seeks to address the issue concerning the treatment of inguinal lymph nodes (LN). Of these 45 patients, five had verrucous carcinoma and the other 40 had squamous cell carcinoma. Eighteen patients had inguinal lymph nodes (LNs) metastasis and received treatments of inguinal LNs involving bilateral inguinal LN dissection or unilateral inguinal LN dissection with or without postoperative radiotherapy. The median follow-up was 37 months. The ultimate local and regional controls for patients with verrucous carcinoma were 100 and 100%, respectively. Among the 40 patients with squamous cell carcinoma, the overall local control rate was 90%. The 5-year overall survival (OS) and disease-free survival (DFS) rates of patients without or with pathological inguinal LN metastasis were 70 vs. 22% (p=0.01), and 55 vs. 16% (p=0.004), respectively. The regional failure rates after inguinal LN dissection for pathological inguinal LN metastasis were 11% (1/9) and 60% (3/5) in patients with and without adjuvant radiotherapy. This study demonstrates that verrucous carcinoma shows excellent treatment outcomes following surgery alone. Squamous cell carcinoma of the penis is associated with a high incidence of inguinal lymph node metastasis. Elective groin dissection is indicated for all penile cancer patients except those with verrucous carcinoma and pT1 cancer with well-differentiated tumor. For patients with pathologically positive inguinal LN metastasis, adjuvant radiotherapy can increase inguinal control in this study. It warrants further prospective trial to prove the value of adjuvant radiotherapy in patients with pathological documented inguinal LN metastasis in penile cancer. 相似文献
997.
Histological analysis of the ligamentum flavum of patients with dialysis-related spondyloarthropathy
Kenshiro Inatomi Tomoko Matsumoto Tadashi Tomonaga Masao Eto Hiroyuki Shindo Tomayoshi Hayashi Hiroaki Konishi 《Journal of orthopaedic science》2004,9(3):285-290
Dialysis-related spondyloarthropathy (DRS) is a severe complication of long-term hemodialysis that ultimately leads to functional disability of the upper and lower extremities. Although the cause of this disease is still unknown, it is thought that amyloid deposits are involved. 2-Microglobulin (2M) is a major component of amyloid fibrils, some of which are modified with the advanced glycation end-product (AGE). To clarify the pathophysiology of DRS we histologically examined the ligamentum flavum of the cervical spine in 15 patients with DRS. The mean duration of hemodialysis was 20 years (12–27 years). In addition to the congo red stain for amyloid, 2M and AGE were detected by immunohistochemical methods. Macrophages were stained with CD68 antibody. Amyloid deposits were found in tissues, although the extent of the stained area differed among the patients. Part of the amyloid deposit area was positively immunostained for 2M and AGE. In 10 cases macrophages positive for CD68 infiltrated around the amyloid deposits. Comparing these histological findings with the dialysis duration, more positive staining areas for 2M and AGE were found in the tissue from patients with long-term dialysis. These findings suggest that both 2M and AGE play roles in the pathogenesis of DRS. 相似文献
998.
Die laparoskopische Chirurgie hat sich in den letzten Jahren zunehmend verbreitet und sich für einige Indikationen sogar zum Goldstandard entwickelt. Auch für kolorektale Eingriffe wird der laparoskopische Zugang zunehmend benutzt, wobei jedoch im Hinblick auf die Sicherheit bei onkologischen Koloneingriffen noch keine abschließende Beurteilung möglich ist. Die operative Therapie der Rektumkarzinome, die durch die Einführung der totalen mesorektalen Exzision (TME) zusätzliche Vorteile hinsichtlich der Rate an Lokalrezidiven erfahren hat, war bislang nicht Gegenstand der laparoskopischen Operationstechnik, da die angenommene Lernkurve und die fragliche onkologische Sicherheit einen derartigen Therapieansatz nicht zuließen.In der hier diskutierten Studie wurde bei Patienten mit Rektumkarzinom die Operation mit TME laparoskopisch durchgeführt. Es konnte gezeigt werden, dass sowohl die onkologischen Ergebnisse (Rezidivrate und Überleben) als auch das kurzfristige Outcome (Mortalität und Morbidität) mit den Ergebnissen der konventionell durchgeführten Operation vergleichbar sind. Ferner bleiben für die Patienten die von anderen laparoskopischen Operationen bekannten Vorteile (Schmerzreduktion, frühe Mobilisation, frühe Darmpassage) erhalten. Die Weiterentwicklung der laparoskopischen Technik könnte hier noch weitere Vorteile bringen, sofern die Konversionsrate zum konventionellen Verfahren durch adäquate Patientenselektion begrenzt werden kann. 相似文献
999.
Theodor W. Kaulich Ulf Lamprecht Frank Paulsen Frank Kahmann Uwe Maurer Thomas Oliver Henkel Wolfgang Loeser Karl-Horst Bichler Fridtjof Nüsslin Michael Bamberg 《Strahlentherapie und Onkologie》2002,178(10):548-555
BACKGROUND: Interstitial brachytherapy with I-125 seeds can be used for successful treatment of early stage prostate cancer. There is presented the technique of permanent transperineal implantation of I-125 seeds with intraoperative treatment planning which is suited for the treatment of prostate cancer up to the clinical stage of T2a. MATERIAL AND METHODS: Some weeks before the implantation of the seeds the prostate volume is determined using transrectal ultrasound (TRUS) so as to estimate the required number of I-125 seeds. At the outset of the treatment the prostate is stabilized by two perineally inserted needles. Subsequently there is carried out an ultrasound guided treatment planning that allows to optimize the distribution of the seeds within the prostate. In interstitial brachytherapy we use RAPID STRANDS((R)), i. e. the I-125 seeds are embedded in vicryl suture at distances of 1 cm. During implantation of the I-125 seeds the transversal placement of the applicator needles is controlled by TRUS and the cranio-caudal placement of the applicator needles is controlled using the fluoroscopic unit as well as TRUS. About 4 weeks after the implantation of the seeds there is carried out a postoperative computation of the dose distribution of the implant using CT imaging. RESULTS: The procedure possesses the advantage that ultrasound imaging, treatment planning and seed implantation are carried out with the prostate remaining in an unaltered position. During implantation the combined imaging of TRUS and fluoroscopy allows a safe placement of the seeds with in the prostate. CONCLUSION: The methods for the calculation of the actually attained dose distribution must still be optimized, because the postoperative examination of the individual results has so far been possible only with difficulties resulting from methodological inconveniences. 相似文献
1000.
MR patterns of involvement of humeral head osteonecrosis 总被引:1,自引:0,他引:1
PURPOSE: To characterize osteonecrosis of the humeral head on coronal and axial MR images. METHODS: We retrospectively reviewed MR examinations in patients with humeral head osteonecrosis. The angle of the entire affected articular surface at three levels was measured and an angle subtended by the margins of osteonecrosis was also measured. RESULTS: The appearance of osteonecrosis is identical to that in the femoral head with signal abnormality (13/13), double-line sign (7/13), and subchondral fractures (3/13). The superior aspect of the humeral head was the most common location of osteonecrosis. The MR staging resulted as follows: stage II (6/13), stage IIIA (1/13), stage IIIB (1/13), and stage IV (5/13). The maximum percentage of involvement of the articular surface demonstrated the following distribution: 0% to 25%, 0/11; 25% to 50%, 1/13; 50% to 75%, 5/13; and 75% to 100%, 7/13. CONCLUSIONS: Quantitative analysis of the percentage of involvement of the humeral head was performed and indicates that in most cases, 75% to 100% of the articular surface at the levels measured was involved. 相似文献