全文获取类型
收费全文 | 5992篇 |
免费 | 364篇 |
国内免费 | 43篇 |
专业分类
耳鼻咽喉 | 163篇 |
儿科学 | 122篇 |
妇产科学 | 31篇 |
基础医学 | 749篇 |
口腔科学 | 81篇 |
临床医学 | 532篇 |
内科学 | 1140篇 |
皮肤病学 | 208篇 |
神经病学 | 587篇 |
特种医学 | 349篇 |
外科学 | 1219篇 |
综合类 | 38篇 |
一般理论 | 4篇 |
预防医学 | 188篇 |
眼科学 | 63篇 |
药学 | 560篇 |
中国医学 | 8篇 |
肿瘤学 | 357篇 |
出版年
2023年 | 38篇 |
2022年 | 62篇 |
2021年 | 125篇 |
2020年 | 78篇 |
2019年 | 113篇 |
2018年 | 134篇 |
2017年 | 105篇 |
2016年 | 146篇 |
2015年 | 207篇 |
2014年 | 197篇 |
2013年 | 294篇 |
2012年 | 442篇 |
2011年 | 439篇 |
2010年 | 281篇 |
2009年 | 251篇 |
2008年 | 397篇 |
2007年 | 443篇 |
2006年 | 373篇 |
2005年 | 347篇 |
2004年 | 339篇 |
2003年 | 292篇 |
2002年 | 293篇 |
2001年 | 78篇 |
2000年 | 75篇 |
1999年 | 76篇 |
1998年 | 55篇 |
1997年 | 59篇 |
1996年 | 35篇 |
1995年 | 35篇 |
1994年 | 40篇 |
1993年 | 42篇 |
1992年 | 36篇 |
1991年 | 38篇 |
1990年 | 38篇 |
1989年 | 22篇 |
1988年 | 22篇 |
1987年 | 34篇 |
1986年 | 25篇 |
1985年 | 26篇 |
1984年 | 18篇 |
1983年 | 20篇 |
1982年 | 20篇 |
1981年 | 14篇 |
1980年 | 12篇 |
1979年 | 12篇 |
1978年 | 14篇 |
1977年 | 13篇 |
1976年 | 19篇 |
1975年 | 18篇 |
1967年 | 21篇 |
排序方式: 共有6399条查询结果,搜索用时 31 毫秒
51.
Baris Turkbey Sheng Xu Jochen Kruecker Julia Locklin Yuxi Pang Marcelino Bernardo Maria J. Merino Bradford J. Wood Peter L. Choyke Peter A. Pinto 《BJU international》2011,107(1):53-57
Study Type – Diagnostic (exploratory cohort)Level of Evidence 2b What’s known on the subject? and What does the study add? Currently, systematic prostate biopsies are obtained with minimal information about their actual location. This study demonstrates that a electromagnetically tracked ultrasound probe can be used to guide biopsies into specific areas of the prostate. By registering the ultrasound to an MRI scan of the prostate, obtained prior to biopsy, it is possible to accurately map the location of biopsies. Thus, if a patient requires a repeat biopsy, or there is a question about whether a specific area of the prostate was sampled, this system can be used to more accurately guide biopsies in the future. OBJECTIVE To develop a system that documents the location of transrectal ultrasonography (TRUS)‐guided prostate biopsies by fusing them to MRI scans obtained prior to biopsy, as the actual location of prostate biopsies is rarely known. PATIENTS AND METHODS Fifty patients (median age 61) with a median prostate‐specific antigen (PSA) of 5.8 ng/ml underwent 3T endorectal coil MRI prior to biopsy. 3D TRUS images were obtained just prior to standard TRUS‐guided 12‐core sextant biopsies wherein an electromagnetic positioning device was attached to the needle guide and TRUS probe in order to track the position of each needle pass. The 3D‐TRUS image documenting the location of each biopsy was fused electronically to the T2‐weighted MRI. Each biopsy needle track was marked on the TRUS images and these were then transposed onto the MRI. Each biopsy site was classified pathologically as positive or negative for cancer and the Gleason score was determined. RESULTS The location of all (n= 605) needle biopsy tracks was successfully documented on the T2‐weighted (T2W) MRI. Among 50 patients, 20 had 56 positive cores. At the sites of biopsy, T2W signal was considered ‘positive’ for cancer (i.e. low in signal intensity) in 34 of 56 sites. CONCLUSION It is feasible to document the location of TRUS‐guided prostate biopsies on pre‐procedure MRI by fusing the pre‐procedure TRUS to an endorectal coil MRI using electromagnetic needle tracking. This procedure may be useful in documenting the location of prior biopsies, improving quality control and thereby avoiding under‐sampling of the prostate as well as directing subsequent biopsies to regions of the prostate not previously sampled. 相似文献
52.
Jeanmonod P Sperling J Seidel R Richter S Kollmar O Schuld J 《International surgery》2011,96(2):117-119
A 49-year-old woman presented with acute abdominal pain in the right iliac fossa in our emergency department. Pain was abrupt in onset and severely colicky in nature. Abnormal laboratory values included a C-reactive protein of 75 mg/L and a CA-125 of 70.3 U/mL. White blood cell count was normal. Abdominal computed tomography (CT) scan revealed an inhomogeneous mass of 9.5 x 3.5 x 5.5 cm in diameter close to the appendix vermiformis and the sigmoid colon. Because of the clinical symptoms of an acute abdomen an explorative laparotomy was performed. Intraoperatively a pedunculated tumor beginning at the serosa of the sigmoid colon was found. The appendix was unremarkable. The macroscopic aspect as well as the backtable incision of the tumor was suspicious of an intraperitoneal liposarcoma. Rapid section and histopathologic examination revealed necrotic fat tissue without any malignancy. The patient was discharged from the hospital 7 days after the operation with normal laboratory parameters and without further complication. When epiploic appendagitis is evident as a big tumor mass in addition to clinical symptoms of an acute abdomen and elevated tumor markers, surgical exploration is mandatory. 相似文献
53.
Katrin Meyer Reinhard C. Klocke Jochen D. Schipke Emmeran Gams Bernhard Korbmacher 《European journal of cardio-thoracic surgery》2008,34(2):326-331
BACKGROUND: After open-chest cardiac surgery, ventricular function remains depressed (myocardial stunning). Catecholamines (epinephrine) improve ventricular function by increasing the intracellular Ca(2+) concentration. In parallel, the oxygen consumption is increased, so that the hitherto intact myocardium can be jeopardized. In the very insufficient ventricle, epinephrine can even become ineffective. Since Ca(2+) sensitizers provide another therapeutic avenue, the effects of epinephrine and levosimendan on postischemic hemodynamics were investigated. METHODS: After hemodynamic steady state, isolated, blood (erythrocyte-enriched Krebs-Henseleit solution)-perfused rabbit hearts were subjected to 25 min normothermic, no-flow ischemia and 20 min reperfusion. Heart rate (HR), cardiac output (CO), left ventricular pressure (LVP), coronary blood flow (CBF), and arterio-venous oxygen difference (AVDO(2)) were recorded during reperfusion and after administration of either epinephrine (n=16; 0.03 micromol), or levosimendan (n=11; 0.75 micromol) or epinephrine plus levosimendan (n=5). RESULTS: Epinephrine increased HR (19%, p=0.01) and improved hemodynamics in terms of CO (62%, p=0.0006), stroke volume SV (46%, p=0.02), stroke work W (158%, p=0.01), LVP(max) (58%, p=0.0001), maximal pressure increase dP/dt(max)(140%, p=0.0004), minimal pressure increase dP/dt(min) (104%, p=0.0002), LVP(ed) (-26%, p=0.02), and increased coronary resistance CR (31%, p=0.05). Epinephrine impaired hemodynamics in terms of AVDO(2) (+63%, p=0.003), myocardial oxygen consumption MVO(2) (+67%, p=0.0003) and MVO(2)/beat (+36%, p=0.01). External efficiency eta was increased by 92% (p=0.02). Levosimendan in postischemic hearts increased HR (32%, p=0.009) and improved hemodynamics in terms of CO (85%, p=0.01), SV (44%, p=0.03), W (115%, p=0.04), LVP(max) (95%, p=0.04), dP/dt(max) (133%, p=0.009), dP/dt(min) (121%, p=0.007), LVP(ed) (-63%, p=0.0006), and CR (-17%; n.s., p=0.1). It altered hemodynamics in terms of AVDO(2) (+7.0%; n.s., p=0.3) and MVO(2) (+32%, p=0.007) and MVO(2)/beat (+2.3%; n.s., p=0.4). External efficiency was increased by 307% (p=0.04). In five additional extremely dysfunctional rabbit hearts, epinephrine was ineffective. Additional levosimendan increased hemodynamics in terms of HR (56%; n.s., p=0.1), CO (159%, p=0.04), SV (89%, p=0.03), W (588%, p=0.02), LVP(max) (168%, p=0.03), dP/dt(max) (102%, p=0.005), dP/dt(min) (78%, p=0.006), LVP(ed) (-98%, p=0.0006), and CR (-50%, p=0.02). It altered hemodynamics in terms of AVDO(2) (-11%; n.s., p=0.05), MVO(2) (+131%, p=0.04) and MVO(2)/beat (+171%, p=0.03). External efficiency was increased by 212% (p=0.04). CONCLUSION: In contrast to epinephrine, levosimendan improves ventricular function without increasing oxygen demand, thereby considerably improving external efficiency. Even during epinephrine resistance in extremely dysfunctional hearts, levosimendan successfully improves ventricular function. 相似文献
54.
OBJECT: The purpose of this study was to clarify whether cerebrospinal fluid (CSF) leakage into the subdural space is involved in the genesis of chronic subdural hematoma (CSDH) and subdural hygroma (SH) and to clarify whether this leakage of CSF into the subdural space influences the postoperative recurrence rate of CSDH and SH. METHODS: In this prospective observational study, 75 cases involving patients treated surgically for CSDH (67 patients) or SH (8 patients) were evaluated with respect to clinical and radiological findings at presentation, the content of beta -trace protein (beta TP) in the subdural fluid (betaTPSF) and serum (betaTPSER), and the CSDH/SH recurrence rate. The betaTPSF was considered to indicate an admixture of CSF to the subdural fluid if betaTPSF/betaTPSER>2. RESULTS: The median beta TPSF level for the whole patient group was 4.29 mg/L (range 0.33-51 mg/L). Cerebrospinal fluid leakage, as indicated by betaTPSF/betaTPSER>2, was found to be present in 93% of the patients with CSDH and in 100% of the patients with SH (p=0.724). In patients who later had to undergo repeated surgery for recurrence of CSDH/SH, the betaTPSF concentrations (median 6.69 mg/L, range 0.59-51 mg/L) were significantly higher (p=0.04) than in patients not requiring reoperation (median 4.12 mg/L, range 0.33-26.8 mg/L). CONCLUSIONS: As indicated by the presence of betaTP in the subdural fluid, CSF leakage into the subdural space is present in the vast majority of patients with CSDH and SH. This leakage could be involved in the pathogenesis of CSDH and SH. Patients who experience recurrences of CSDH and SH have significantly higher concentrations of betaTPSF at initial presentation than patients not requiring reoperation for recurrence. These findings are presented in the literature for the first time and have to be confirmed and expanded upon by further studies. 相似文献
55.
The experiences in treating 93 consecutive patients (56 males, 37 females; mean age, 38.5 years; range, 4-69 years), including 76 patients with primary malignant bone tumors and 17 patients with soft tissue sarcomas involving the innominate bone, are reported. Oncologic and functional results were investigated in relation to the tumor stage, to the achieved surgical margin, and to the surgical procedure (hemipelvectomy, internal hemipelvectomy and endoprosthetic replacement, and continuity resection). The mean followup was 48 months (range, 8-222 months). The 5-year survival was 86% in patients with low-grade malignant bone tumors, 42% in patients with high-grade malignant bone tumors, and 25% in patients with high-grade soft tissue sarcomas. Survival was influenced by the grade of malignancy, the tumor stage, and the achieved surgical margins. Forty-six patients who survived were examined an average of 36 months after primary surgery. Excellent and good functional results were seen in 82% of patients who underwent continuity resection and in 55.5% of patients who underwent partial or total internal hemipelvectomy. All patients who survived hemipelvectomy had poor functional results. Surgical treatment of pelvic sarcomas is an extensive procedure with a considerable incidence of complications. It requires the knowledge of different techniques of resection and reconstruction of bone, joints, soft tissue, and intrapelvic organs. 相似文献
56.
Malaria infections repeatedly have been reported to induce nephrotic syndrome and acute renal failure. Questions have been
raised whether the association of a nephrotic syndrome with quartan malaria was only coincidental, and whether the acute renal
failure was a specific or unspecific consequence of Plasmodium falciparum infection. This review attempts to answer questions about “chronic quartan malaria nephropathy” and “acute falciparum malaria
nephropathy”. The literature review was performed on all publications on kidney involvement in human and experimental malarial
infections accessible in PubMed or available at the library of the London School of Hygiene and Tropical Medicine. The association
of a nephrotic syndrome with quartan malaria was mostly described before 1975 in children and rarely in adult patients living
in areas endemic for Plasmodium malariae. The pooled data on malaria-induced acute renal failure included children and adults acquiring falciparum malaria in endemic
areas either as natives or as travellers from non-tropical countries. Non-immunes (not living in endemic areas) had a higher
risk of developing acute renal failure than semi-immunes (living in endemic areas). Children with cerebral malaria had a higher
rate and more severe course of acute renal failure than children with mild malaria. Today, there is no evidence of a dominant
role of steroid-resistant and chronic “malarial glomerulopathies” in children with a nephrotic syndrome in Africa. Acute renal
failure was a frequent and serious complication of falciparum malaria in non-immune adults. However, recently it has been
reported more often in semi-immune African children with associated morbidity and mortality. 相似文献
57.
Gait analysis of patients with resurfacing hip arthroplasty compared with hip osteoarthritis and standard total hip arthroplasty 总被引:12,自引:0,他引:12
Mont MA Seyler TM Ragland PS Starr R Erhart J Bhave A 《The Journal of arthroplasty》2007,22(1):100-108
Patients with standard total hip arthroplasties may have reduced hip abduction and extension moments when compared with normal nonosteoarthritic hips. In comparison, patients after resurfacing total hip arthroplasty appear to have a near-normal gait. The authors evaluated temporal-spatial parameters, hip kinematics, and kinetics in hip resurfacing patients compared with patients with unilateral osteoarthritic hips and unilateral standard total hip arthroplasties. Patients with resurfacing walked faster (average 1.26 m/s) and were comparable with normals. There were no significant differences in hip abductor and extensor moments of patients with resurfacing compared with patients in the standard hip arthroplasty group. This study showed more normal hip kinematics and functionality in resurfacing hip arthroplasty, which may be due to the large femoral head. 相似文献
58.
Hans Polzer Sigmund Polzer Mareen Brumann Wolf Mutschler Markus Regauer 《World journal of orthopedics》2014,5(1):6-13
Hallux rigidus describes the osteoarthritis of the first metatarsophalangeal joint. It was first mentioned in 1887. Since then a multitude of terms have been introduced referring to the same disease. The main complaints are pain especially during movement and a limited range of motion. Radiographically the typical signs of osteoarthritis can be observed starting at the dorsal portion of the joint. Numerous classifications make the comparison of the different studies difficult. If non-operative treatment fails to resolve the symptoms operative treatment is indicated. The most studied procedure with reproducible results is the arthrodesis. Nevertheless, many patients refuse this treatment option, favouring a procedure preserving motion. Different motion preserving and joint sacrificing operations such as arthroplasty are available. In this review we focus on motion and joint preserving procedures. Numerous joint preserving osteotomies have been described. Most of them try to relocate the viable plantar cartilage more dorsally, to decompress the joint and to increase dorsiflexion of the first metatarsal bone. Multiple studies are available investigating these procedures. Most of them suffer from low quality, short follow up and small patient numbers. Consequently the grade of recommendation is low. Nonetheless, joint preserving procedures are appealing because if they fail to relief the symptoms an arthrodesis or arthroplasty can still be performed thereafter. 相似文献
59.
Renal allograft function in matched pediatric and adult recipient pairs of the same donor 总被引:5,自引:0,他引:5
BACKGROUND: To study the effect of donor age on kidney function, the authors investigated matched pairs from the same kidney donor given to a pediatric or an adult recipient. METHODS: Fifteen matched pairs of an adult and a pediatric patient, selected from the Eurotransplant registry, receiving the renal graft from the same cadaveric donor were selected for analysis of graft function over 7 years. Nine matched pairs were from adult donors (mean age, 40 years; range, 23-60 years) and six from pediatric donors (mean age, 11 years; range, 4-15 years). All recipients had comparable immunosuppression with cyclosporine A, prednisolone, and azathioprine and comparable numbers of acute rejection, cytomegalovirus reactivation, and antihypertensive therapy. Mean age of pediatric and adult recipients at transplantation was 5 years (range, 1-9 years) and 38 years (range, 25-60 years), respectively. RESULTS: The calculated glomerular filtration rate (GFR) corrected to body surface area was not different in adult and pediatric recipients. Initial absolute GFR was significantly lower in pediatric recipients (27 mL/ min; range, 17-38 mL/min) than in adult recipients (54 mL/min; range, 25-74 mL/min) (P <0.05) and remained lower in the following years. Initially, pediatric donor kidneys transplanted into pediatric recipients showed a lower absolute GFR than those transplanted into adults, however, approaching the GFR in adult recipients later. Adult donor kidneys transplanted into pediatric recipients showed a persistently lower absolute GFR in children compared with those transplanted into adult recipients. CONCLUSIONS: The authors conclude that adult donor kidneys in pediatric recipients decrease GFR in the early stages and lack an increase in GFR with growth of the child. 相似文献
60.
von Breunig F Wappler F Hagel C von Richthofen V Fiege M Weisshorn R Stavrou D Schulte am Esch J 《Anesthesiology》2004,100(4):789-794
BACKGROUND: It has been suggested that malignant hyperthermia (MH) can be diagnosed by specific myopathologic alterations. The purpose of this study was to investigate whether there are characteristic myopathologic changes in skeletal muscles of MH-susceptible (MHS) compared with MH-normal (MHN) patients. METHODS: Four hundred forty patients with clinical suspicion of MH were classified as MHN, MH equivocal (MHE), or MHS by the in vitro contracture test with halothane and caffeine. In addition, a small muscle sample excised from each patient was analyzed by histologic, histochemical, immunohistochemical, and computer-aided morphometric methods. RESULTS: MHN was diagnosed in 243 patients, MHE was diagnosed in 65, and MHS was diagnosed in 132. No myopathologic abnormalities were found in 53.5% of the MHN, 53.9% of the MHE, and 56.1% of the MHS patients. Thirty-five percent of all patients showed one, 9.8% showed two, and only 0.9% showed three different pathologic findings within skeletal muscle preparations. The frequency of pathologic findings did not differ between the MHN and the MHS patients; only fiber type I predominance was observed more often in MHN. MHE patients could not be assigned to a diagnostic group by detection of myopathologic alterations. In six clinically unaffected patients, a former unrecognized myopathy, such as central core disease, was diagnosed. This disease is characterized by a specific alteration (cores). CONCLUSIONS: Histologic differences between MHS and MHN statuses could not be demonstrated in this study. Histopathologic examinations can neither improve the diagnosis of MH nor contribute to a better definition of the MH status. However, histopathologic examinations might be useful to detect formerly unrecognized specific myopathies. 相似文献