全文获取类型
收费全文 | 7402篇 |
免费 | 414篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 41篇 |
儿科学 | 113篇 |
妇产科学 | 149篇 |
基础医学 | 1105篇 |
口腔科学 | 227篇 |
临床医学 | 603篇 |
内科学 | 1469篇 |
皮肤病学 | 182篇 |
神经病学 | 799篇 |
特种医学 | 411篇 |
外科学 | 1053篇 |
综合类 | 71篇 |
一般理论 | 3篇 |
预防医学 | 360篇 |
眼科学 | 306篇 |
药学 | 488篇 |
中国医学 | 16篇 |
肿瘤学 | 454篇 |
出版年
2023年 | 25篇 |
2022年 | 91篇 |
2021年 | 136篇 |
2020年 | 76篇 |
2019年 | 100篇 |
2018年 | 115篇 |
2017年 | 110篇 |
2016年 | 141篇 |
2015年 | 177篇 |
2014年 | 249篇 |
2013年 | 312篇 |
2012年 | 464篇 |
2011年 | 534篇 |
2010年 | 336篇 |
2009年 | 306篇 |
2008年 | 544篇 |
2007年 | 548篇 |
2006年 | 507篇 |
2005年 | 505篇 |
2004年 | 489篇 |
2003年 | 496篇 |
2002年 | 472篇 |
2001年 | 89篇 |
2000年 | 53篇 |
1999年 | 103篇 |
1998年 | 97篇 |
1997年 | 90篇 |
1996年 | 55篇 |
1995年 | 54篇 |
1994年 | 43篇 |
1993年 | 39篇 |
1992年 | 42篇 |
1991年 | 27篇 |
1990年 | 27篇 |
1989年 | 18篇 |
1988年 | 14篇 |
1987年 | 19篇 |
1986年 | 8篇 |
1985年 | 13篇 |
1984年 | 19篇 |
1983年 | 22篇 |
1982年 | 17篇 |
1981年 | 22篇 |
1980年 | 14篇 |
1978年 | 18篇 |
1977年 | 17篇 |
1976年 | 12篇 |
1974年 | 15篇 |
1973年 | 8篇 |
1965年 | 8篇 |
排序方式: 共有7850条查询结果,搜索用时 15 毫秒
81.
Didier Mathieu Alain Rahmouni Norbert Vasile Nedal Jazaerli Christophe Duvoux Jeanne Tran Van Nhieu Elie Serge Zafrani 《Journal of magnetic resonance imaging : JMRI》1994,4(3):506-508
This case report illustrates atypical magnetic resonance (MR) imaging findings in a liver hemangioma mimicking a malignant lesion—lower signal intensity than cerebrospinal fluid on T2-weighted spin-echo images and lack of early enhancement on dynamic contrast material—enhanced gradient-echo images. Pathologic analysis demonstrated nearly total replacement of the vascular cavities by dense fibrous tissue. In this rare, sclerosed form, this lesion could not be defined as a hemangioma with MR imaging. 相似文献
82.
Radical Resection of Giant Congenital Melanocytic Nevus and Reconstruction With Meek-Graft Covered Integra Dermal Template 总被引:2,自引:0,他引:2
Jürgen Kopp MD E. Magnus Noah MD Albert Rübben MD PhD Hans F. Merk MD PhD Norbert Pallua MD PhD 《Dermatologic surgery》2003,29(6):653-657
BACKGROUND: Giant congenital melanocytic nevi represent a surgical challenge, particularly in cases in which the size of the nevus exceeds certain extend and malignant transformations have to be considered. OBJECTIVE: To discuss through case report considerable surgical options when extensive giant congenital melanocytic nevi with malignant transformation are encountered. METHODS: We present an unusual case of a giant congenital melanocytic nevi of the entire back of a 44-year-old patient. To achieve radical resection with direct appropriate wound closure and acceptable outcome, the integument of the entire back was excised and covered with Integra, followed by split-thickness skin grafting after stable integration of the matrix. RESULTS: The approach resulted in a complete excision of the tumor and acceptable cosmetic and excellent biomechanical outcome. CONCLUSION: The introduced practice demonstrates a useful alternative to established methods, particularly if tumor excision in large areas and subsequent wound closure might be achieved in one procedure. 相似文献
83.
Daniel A. Reuter Martin Anetseder Rainer Müller Norbert Roewer Edmund J. Hartung 《Journal canadien d'anesthésie》2003,50(7):643-648
PURPOSE: The ryanodine contracture test (RCT) using the plant alkaloid ryanodine as the triggering agent has been proposed to reduce equivocal results of the in vitro caffeine-halothane-contracture test (IVCT), which is the accepted and standardized procedure to diagnose malignant hyperthermia (MH). However, the response of skeletal muscle of non-MH affected patients (controls) to ryanodine has not yet been characterized. METHODS: Skeletal muscle biopsies were studied in 33 controls and in six patients with a history of fulminant MH. Following the IVCT, the RCT was performed in all specimens using ryanodine 1 micro M. Onset time of contracture and time to reach a contracture level of 10 mN above lowest resting tension and above predrug tension were calculated. RESULTS: With the standard IVCT, all controls were labelled MH non-susceptible; all clinically diagnosed MH patients were labelled MH susceptible. With ryanodine, control muscle differed from MH susceptible muscle regarding onset time of contracture (26 vs 3.8 min, P < 0.05) and time to reach a contracture of 10 mN (49 vs 12.5 min, P < 0.05; all median). Tissue viability and patient's age significantly influenced contracture times. CONCLUSIONS: Despite the highly specific binding of ryanodine at the myocytic sarcoplasmic reticulum, the wide range of contracture times of the controls points toward heterogeneity of ryanodine receptors within physiologic limits. This may also be caused in part by tissue viability and the patients' age. The ryanodine contracture test performed in addition to the IVCT may add clarity into diagnosing a patient as MH-susceptible or not. 相似文献
84.
Van Den Noortgate N Velghe A Petrovic M Vandewiele C Lameire N Voet D Afschrift M 《Journal of nephrology》2003,16(5):658-662
BACKGROUND: Ageing is associated with a progressive loss of renal mass and kidney length and a decline in glomerular filtration rate (GFR). This study evaluated a possible correlation between renal function and kidney size measured by ultrasonography (US), and whether the latter helps estimate GFR in the elderly. METHODS: Twenty-five medically stable elderly patients (mean age 85 +/- 5 yrs) were examined in a geriatric ward at a university hospital. Blood samples were taken to determine serum creatinine (Cr) levels. On the same day, 51chromium ethylenediamine tetraacetic acid (51Cr-EDTA) clearance was performed as the gold standard of GFR. US measured kidney length, transverse and anteroposterior dimensions. RESULTS: Serum Cr (r=-0.67; p=0.0002), Cockcroft-Gault formula (r=0.82; p<0.0001), absolute length (r=0.51; p=0.008) and volume kidney (r=0.46; p=0.02) correlated significantly with GFR. After receiver operating curve (ROC) analysis, length was less specific than sensitive in detecting renal impairment. Adding length to the Cockcroft-Gault formula did not improve GFR estimation (p=0.44). In contrast, adding length to serum Cr levels improved GFR estimation (p=0.015). CONCLUSION: In the elderly, kidney length and volume significantly correlated with GFR. However, length has a low specificity in predicting renal impairment. Therefore, in clinical practice, serum Cr levels and calculated Cr clearance are more useful in predicting renal impairment. However, normal kidney length can help to exclude renal impairment in the elderly at risk of GFR underestimation by a calculated Cr clearance. 相似文献
85.
Outcome in a post-cardiac surgery population with acute renal failure requiring dialysis: does age make a difference? 总被引:3,自引:0,他引:3
Nele Van Den Noortgate Veerle Mouton Caroline Lamot Guido Van Nooten Annemieke Dhondt Raymond Vanholder Marcel Afschrift Norbert Lameire 《Nephrology, dialysis, transplantation》2003,18(4):732-736
BACKGROUND: Acute renal failure (ARF), requiring dialysis (ARF-d), develops in 1-5% of patients undergoing cardiac surgery and is associated with higher in-hospital mortality. Age is one of the known risk factors for the development of ARF. As the ageing population is increasing, the nephrologist will be faced with a large population of elderly patients requiring dialysis following cardiac surgery. The aim of our study was to evaluate the influence of age on and the risk factors for in-hospital mortality. METHODS: Eighty-two patients with ARF following cardiac surgery and requiring dialysis between January 1997 and October 2001 were included. Two groups of patients were studied: the younger population (<70 years, 42 patients, mean age 59+/-10) and an elderly population (>/=70 years, 40 patients, mean age 76+/-4). Severity of disease was evaluated using the SAPS (Simplified Acute Physiology Score), the Liano score and the SHARF (Stuivenberg Hospital Acute Renal Failure) score. RESULTS: Overall mortality in the population with ARF-d was 56.1%. No difference in mortality rate was found between the younger (61.9%) and elderly patient group (50.0%). The two groups were very similar in baseline and procedural characteristics with exception of body weight (P=0.02) and preoperative glomerular filtration rate (P=0.0001). No significant difference was found in the scoring systems between the old and the young (SAPS P=0.52; Liano P=0.96; SHARF T0 P=0.06; SHARF T48 P=0.15). Mortality in the elderly was significantly correlated with hypotension before starting renal replacement therapy (RRT) (P=0.002), mechanical ventilation (P=0.002), presence of multiorgan failure (MOF) (P=0.0001) and higher scores in the severity models (SAPS: P=0.01; Liano: P<0.0001 and SHARF: P<0.0001). CONCLUSION: The outcome in the elderly requiring dialysis due to ARF post-cardiac surgery is comparable with the outcome in a younger population. No significant difference was found in severity of disease between the elderly and the younger. Variables predicting mortality in the elderly are the presence of MOF, mechanical ventilation and hypotension 24 h before starting RRT. These findings indicate that at the time the nephrologist is called for an elderly patient requiring dialysis due to ARF following cardiac surgery, age per se is not a reason to withhold RRT. 相似文献
86.
Van der Struijs NR Van Es EM Raymann RJ Daanen HA 《Aviation, space, and environmental medicine》2008,79(10):941-946
INTRODUCTION: Subjects with a weak cold-induced vasodilatation response (CIVD) to experimental cold-water immersion of the fingers in a laboratory setting have been shown to have a higher risk for local cold injuries when exposed to cold in real life. Most of the cold injuries in real life, however, occur in the foot in cold air rather than in the hand in cold water. Therefore, an experiment was conducted to investigate the within-subject relation between CIVD in the fingers and toes exposed to cold water and cold air. METHODS: In 4 experimental sessions, 11 healthy male subjects immersed their toes and fingers in 5 degrees C water and exposed the fingers and toes to -18 degrees C cold air for 30 min. The pad temperature of the middle three digits was measured. RESULTS: CIVD in water was more pronounced in the fingers (onset time 5.1 +/- 1.8 min; amplitude 5.0 +/- 2.1 degrees C) than in the toes (onset time 10.6 +/- 6.0 min; amplitude 3.0 +/- 1.0 degrees C). Out of 22 skin temperature responses to cold air, 13 were not identifiable as CIVD. The mean skin temperatures for fingers and toes during the last 20 min of cold exposure were 25.6 +/- 7.1 degrees C and 20.9 +/- 6.8 degrees C, respectively, for air and 9.3 +/- 1.9 degrees C and 7.1 +/- 1.3 degrees C for water immersion. There was a strong relation between the mean temperature of the fingers during cold-water immersion and toes during cold air exposure (r = 0.83, P < 0.01), showing that a weak CIVD response in the hand is related to a weak response in the foot. DISCUSSION: We conclude that the cold-water finger immersion test is related to the temperature response in the toes and may thus continue to serve as a valid indicator for the risk of local cold injuries. 相似文献
87.
Echocardiographic monitoring during induction of general anesthesia with a miniaturized esophageal probe 总被引:4,自引:0,他引:4
Zimmermann P Greim C Trautner H Sagmeister U Kraemer K Roewer N 《Anesthesia and analgesia》2003,96(1):21-7, table of contents
Standard transesophageal echocardiography (TEE) does not allow cardiac monitoring during the induction of anesthesia because standard probes would limit the oropharyngeal space and impair mask ventilation and tracheal intubation. We hypothesized that a prototype, miniaturized TEE probe could be safely introduced transnasally in awake patients and that mask ventilation and orotracheal intubation could be performed while continuously monitoring left ventricular (LV) function during the induction of anesthesia. Forty-five patients were studied prospectively. The transnasal TEE probe was introduced through one of the nares and advanced until a transverse plane image of the LV at the level of the papillary muscles was seen. Anesthesia was induced, and the patients were ventilated with a mask that had previously been threaded over the TEE probe via a central perforation. Probe insertion was successful in 12 patients under local anesthesia alone and in an additional 31 patients with a combination of local anesthesia and mild sedation. In two cases, probe placement was unsuccessful. Overall, hemodynamic variables did not change significantly during insertion. No case of significant mucosal bleeding was seen. In one patient, regurgitation of gastric contents occurred without affecting the perioperative outcome. The two-dimensional echocardiogram image quality of the LV during the induction of anesthesia was good or acceptable in 95% of patients. We conclude that transnasal TEE can effectively be used for cardiac monitoring during the induction of general anesthesia. IMPLICATIONS: This study demonstrates that it is feasible and generally safe to introduce a miniaturized transesophageal echocardiography probe transnasally in awake cardiac risk patients to monitor cardiac performance during the induction of general anesthesia. 相似文献
88.
Is colonoscopy alone sufficient to screen for ulcerative colitis-associated colorectal carcinoma? 总被引:2,自引:0,他引:2
Bruewer M Krieglstein CF Utech M Bode M Rijcken E Anthoni C Laukoetter MG Schuermann G Senninger N 《World journal of surgery》2003,27(5):611-615
Patients with ulcerative colitis (UC) are at increased risk for colorectal carcinoma (CAC). Despite the fact that patients at risk are followed closely by colonoscopy to screen for dysplasia, the prevalence of CAC is still unacceptably high. The aim of this study was to evaluate the prevalence of risk factors for CAC, such as dysplasia, and to determine the relevance of colonoscopic surveillance in the group who went on to develop cancer. A series of 24 patients with UC were diagnosed with CAC. The patients' records were analyzed retrospectively for duration of UC, prevalence of preoperative dysplasia, and other cancer risk factors (CRFs) (e.g., pancolitis, primary sclerosing cholangitis, early onset of UC, and backwash ileitis). The mean age of the patients at the time of cancer diagnosis was 43 years with an average UC duration of 15 years (6 patients had had UC less than 8 years). CAC was identified preoperatively by colonoscopy in 15 of 24 patients, with an additional 7 of 15 showing flat dysplasia. Five of nine patients without preoperatively diagnosed CAC had flat dysplasia. Overall, 19 patients had additional CRFs, most of them with at least two more CRFs. Despite a regular colonoscopic follow-up for most patients with UC, flat dysplasia was missed in 12 patients preoperatively. Therefore we suggest that patient information should also always include surgical options in each case where significant cancer risk factors are found. 相似文献
89.
Androgen and estrogen receptors in the human corpus cavernosum penis: immunohistochemical and cell culture results 总被引:3,自引:1,他引:3
Schultheiss D Badalyan R Pilatz A Gabouev AI Schlote N Wefer J von Wasielewski R Mertsching H Sohn M Stief CG Jonas U 《World journal of urology》2003,21(5):320-324
Despite the central and peripheral effects of androgens on the nervous system, the local effects of androgens in the corpus cavernosum penis and their importance for erectile function is still unclear. In this study corpus cavernosum biopsies of eight adult potent patients, aged 19–63 years, undergoing penile deviation surgery (group A) and 12 patients undergoing male-to-female transsexual surgery (group B) were immunostained for nuclear androgen and estrogen-alpha receptors. Additionally, primary corpus cavernosum endothelial cell cultures were obtained from six transsexual patients and exposed to testosterone, dihydrotestosterone, estradiol and progesterone likewise for 7 days. Total cell count was performed and cell metabolic activity was measured by a tetrazolium salt-based assay. Androgen and estrogen-alpha receptors were detected in stromal as well as in endothelial cells. Of all cell nuclei, 74.9% (SD 16.4) in group A and 63.5% (SD 17.1) in group B were positively stained for androgen receptors. The respective percentage of estrogen receptors was 11% (SD 9.5) and 21.2% (SD 12.6). An age-dependent difference in receptor distribution was not observed in either group. In the cell culture system only cultures exposed to testosterone and dihydrotestosterone showed a dose-dependent increase of cell metabolic activity compared to the cultures supplemented with estradiol and progesterone. The significant and age-independent high androgen and low estrogen-alpha receptor distribution found in both groups suggests a possible peripheral effect of androgens at the level of the corpus cavernosum penis in adult humans. This is supported by the observed effect of testosterone and dihydrotestosterone on cell count and endothelial cell metabolism in our cell culture system. The role of estrogens remains unclear. 相似文献
90.
Intra-lesional injections of collagenase are ineffective in the treatment of keloid and hypertrophic scars. 总被引:2,自引:0,他引:2
Norbert Kang Branavan Sivakumar Roy Sanders Charles Nduka David Gault 《Journal of plastic, reconstructive & aesthetic surgery》2006,59(7):693-699
The treatment of keloid and hypertrophic scars remains difficult. Enzymatic digestion of keloid scars has been previously proposed as an effective treatment strategy for reducing the volume of keloid scars. To test this, we administered intra-lesional injections of pure collagenase (between 600 and 4500 units for each scar) into the keloid and hypertrophic scars of seven human volunteers (five keloid and two hypertrophic scars). Five patients (three keloid and two hypertrophic) received more than one injection of collagenase. The treatment resulted in a temporary reduction in scar volume for three of the patients with keloid scars. However, scar volumes for these three patients returned to the same (or greater) levels after 6 months of follow-up. Treatment with collagenase produced no change in scar volume for the two patients with hypertrophic scar. Side effects were numerous and severe including; pain, swelling, blistering, ulceration and ecchymosis at the site of injection. One patient required admission to hospital for 48 h after the first injection. Maximum length of follow-up was 6 months. None of the seven patients completed the study and returned for final follow-up at 2 years. This pilot study suggests that treatment of keloid and hypertrophic scars with intra-lesional injections of collagenase is ineffective. 相似文献