全文获取类型
收费全文 | 1932篇 |
免费 | 117篇 |
国内免费 | 30篇 |
专业分类
耳鼻咽喉 | 39篇 |
儿科学 | 115篇 |
妇产科学 | 45篇 |
基础医学 | 206篇 |
口腔科学 | 29篇 |
临床医学 | 182篇 |
内科学 | 285篇 |
皮肤病学 | 24篇 |
神经病学 | 279篇 |
特种医学 | 228篇 |
外科学 | 253篇 |
综合类 | 36篇 |
预防医学 | 75篇 |
眼科学 | 6篇 |
药学 | 75篇 |
肿瘤学 | 202篇 |
出版年
2021年 | 15篇 |
2019年 | 19篇 |
2018年 | 21篇 |
2017年 | 24篇 |
2016年 | 18篇 |
2015年 | 32篇 |
2014年 | 40篇 |
2013年 | 47篇 |
2012年 | 74篇 |
2011年 | 83篇 |
2010年 | 60篇 |
2009年 | 51篇 |
2008年 | 82篇 |
2007年 | 85篇 |
2006年 | 75篇 |
2005年 | 93篇 |
2004年 | 57篇 |
2003年 | 66篇 |
2002年 | 66篇 |
2001年 | 65篇 |
2000年 | 68篇 |
1999年 | 59篇 |
1998年 | 41篇 |
1997年 | 38篇 |
1996年 | 32篇 |
1995年 | 17篇 |
1994年 | 36篇 |
1993年 | 34篇 |
1992年 | 31篇 |
1991年 | 34篇 |
1990年 | 44篇 |
1989年 | 39篇 |
1988年 | 52篇 |
1987年 | 36篇 |
1986年 | 30篇 |
1985年 | 43篇 |
1984年 | 31篇 |
1983年 | 21篇 |
1982年 | 24篇 |
1981年 | 24篇 |
1980年 | 12篇 |
1979年 | 22篇 |
1978年 | 21篇 |
1977年 | 22篇 |
1975年 | 13篇 |
1974年 | 20篇 |
1973年 | 12篇 |
1972年 | 9篇 |
1970年 | 9篇 |
1966年 | 15篇 |
排序方式: 共有2079条查询结果,搜索用时 15 毫秒
21.
Simultaneous pancreas-kidney transplantation is a therapeutic option for type I diabetics with end-stage renal disease. It aims to correct the uremic state, to normalize glucose hemeostasis, and to ameliorate diabetic complications. Careful donor-recipient selection and meticulous intra-operative and postoperative care will substantially impact recipient morbidity. An understanding of the technical aspects of the surgical procedure and its metabolic and immunological consequences is necessary to successfully manage a pancreas-kidney transplant recipient, many of whom are nursed in intensive care units. A successful outcome is predicted in early recognition of technical complications and aggressive management of rejection to achieve the current 1-year graft survival rates of 75% for pancreas transplants and 84% for kidney transplants. 相似文献
22.
Objectives. To examine the effects of bicalutamide (Casodex), a pure antiandrogen with high specificity for the androgen receptor, on insulin-like growth factor binding protein (IGFBP) expression and apoptotic regression of the rat ventral prostate.Methods. Rats were treated daily with 10 mg/kg body weight bicalutamide or vehicle alone. Ventral prostates were collected at various days of treatment. Northern blot analysis was performed to quantitate expression of genes encoding IGFBPs, and the TUNEL method was used to determine the extent of apoptosis in ventral prostate.Results. In rats treated daily with bicalutamide, increases in mRNA levels of IGFBP-2, -3, -4, and -5 were detectable by Northern blotting by 6 hours and reached 6 to 10-fold of control levels after 5 days of treatment. The time-course of induction of apoptosis in the ventral prostate by bicalutamide, as detected in situ by the TUNEL method, corresponded to the time-course of induction of IGFBP expression.Conclusions. We demonstrate that apoptotic regression of the ventral prostate during bicalutamide treatment is accompanied by increased expression of IGFBP-2, -3, -4, and -5. Rapid induction of IGFBPs, which can limit access of insulin-like growth factors (IGFs) to the IGF-I receptor, may play a role in the induction of apoptosis by antiandrogens, particularly in view of the increasing evidence that IGF-I inhibits apoptosis. These results document a previously unrecognized effect of antiandrogens and extend our previous studies relating IGF physiology to prostate biology. Together with evidence that a strong positive correlation exists between plasma IGF-I levels and prostate cancer risk, our data suggest that IGF physiology may play a key role in prostate cancer biology and is strongly influenced by androgen-targeting therapies. 相似文献
23.
Congenital pulmonary atresia with ventricular septal defect: angiographic and surgical correlates 总被引:1,自引:0,他引:1
Of 181 patients with severe congenital pulmonary atresia and ventricular septal defect or "type IV truncus" (an obsolete term), all but 11% had true central pulmonary arteries. These arteries were demonstrable by large serial biplane angiograms using multiple selective injections into collateral vessels, frequent photographic subtraction, and occasional pulmonary vein-wedge angiograms. These techniques are extremely important for accurate diagnosis and in planning corrective or palliative surgery, which was done in 77% of patients with pulmonary arteries. 相似文献
24.
Zusammenfassung Einige gebräuchliche Modelle unter den Viehbetäubungsapparaten verfügen über Gummipuffer und Rückholfedern. Durch diese Bestandteile wird der vorschnellende Bolzen gebremst und in seine Ausgangsposition zurückgebracht. Wenn man den Gummipuffer und die Rückholfeder vor der Schußabgabe entfernt, kann der Bolzen abreißen und zu einem frei fliegenden Geschoß werden. In einem Suizidfall ist unter solchen Umständen ein 17 cm langes Bolzenstück durch die Stirn in die Schädelkapsel eingedrungen. 相似文献
25.
Introduction of bias in residency-candidate interviews 总被引:1,自引:0,他引:1
We have developed, as part of our resident applicant ranking process, a computerized weighted scoring system incorporating, among other variables, the interview score (IS). This study was undertaken to test the IS as a dependent variable when the applicant file is available during the interview. Over a 3-year period, each of two faculty members interviewed 133 candidates in a "blinded" fashion (file unavailable) or 290 candidates with an "open" file. The mean discrepancy between paired interviewers (1 to 10 scale) was 1.34 +/- 0.10 for the blinded group versus 0.93 +/- 0.06 for the open group (p less than 0.001). Individual and multiple regression analysis were used to test the IS as a dependent variable in the open group, with the blinded group as a control. In each instance (except clerkship grades), the IS correlated more closely with other parameters (p less than 0.05) in the open group. Correlation coefficients were 0.27 (blinded) and 0.64 (open) for weighted scores combining all parameters (p less than 0.001) and 0.39 (blinded) and 0.65 (open) for multiple linear regression analysis (p less than 0.001). We conclude that the IS is significantly influenced if other objective variables are at hand, thus deflating the actual weight of the interview. To accurately quantify the value of the interview, a correction factor must be applied, or, more appropriately, the interview must be conducted blindly. 相似文献
26.
Richard I. Hall J. Thomas Murphy Emerson A. Moffitt Roderick Landymore P. Timothy Pollak Laurie Poole 《Journal canadien d'anesthésie》1991,38(8):996-1004
The purpose of this study was to compare propofol-sufentanil with enflurane-sufentanil anaesthesia for patients undergoing elective coronary artery bypass graft (CABG) surgery with respect to changes in (1) haemodynamic variables; (2) myocardial blood flow and metabolism; (3) serum cortisol, triglyceride, lipoprotein concentrations and liver function; and (4) recovery characteristics. Forty-seven patients with preserved ventricular function (ejection fraction greater than 40%, left ventricular end diastolic pressure less than or equal to 16 mmHg) were studied. Patients in Group A (n = 24) received sufentanil 0.2 microgram.kg-1 and propofol 1-2 mg.kg-1 for induction of anaesthesia which was maintained with a variable rate propofol (50-200 micrograms.kg-1.min-1) infusion and supplemental sufentanil (maximum total 5 micrograms.kg-1). Patients in Group B (n = 23) received sufentanil 5 micrograms.kg-1 for induction of anaesthesia which was maintained with enflurane and supplemental sufentanil (maximum total 7 micrograms.kg-1). Haemodynamic and myocardial metabolic profiles were determined at the awake-sedated, post-induction, post-intubation, first skin incision, post-sternotomy, and pre-cardiopulmonary bypass intervals. Induction of anaesthesia produced a larger reduction in systolic blood pressure in Group A (156 +/- 22 to 104 +/- 20 mmHg vs 152 +/- 26 to 124 +/- 24 mmHg; P less than 0.05). No statistical differences were detected at any other time or in any other variable including myocardial lactate production (n = 13 events in each group), time to tracheal extubation and time to discharge from the ICU. We concluded that, apart from hypotension on induction of anaesthesia, propofol-sufentanil anaesthesia produced anaesthetic conditions equivalent to enflurane-sufentanil anaesthesia for CABG surgery. 相似文献
27.
A K Dosekun M R First P K Chandran K S Kant P Glas-Greenwalt M A Weiss J W Alexander V E Pollak 《Clinical nephrology》1982,18(2):101-105
Hyperacute and renal allograft failure, whether due to rejection or other mechanisms, such as perfusion injury, is usually associated with extensive intraglomerular fibrin deposition and allograft loss. Defibrination with ancrod was used to treat a patient with hyperacute renal allograft failure and extensive glomerular fibrin deposition and necrosis. The patient's plasma had normal fibrinolytic activity but a complete absence of the ability to generate prostacyclin-like activity from rat aortic endothelium "in vitro". Treatment was associated with complete recovery of renal function, disappearance of glomerular fibrin, and restoration toward normal of glomerular structure. 相似文献
28.
Rachael Z Stolzenberg-Solomon Paul Limburg Michael Pollak Philip R Taylor Jarmo Virtamo Demetrius Albanes 《Cancer epidemiology, biomarkers & prevention》2004,13(3):438-444
To investigate whether insulin-like growth factor (IGF)-1 and IGF-binding protein-3 (IGFBP-3) are prospectively associated with exocrine pancreatic cancer, we conducted a nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort of 29,133 male Finnish smokers, aged 50-69 years. To avoid the potential influence of subclinical cancer on IGF-1 and IGFBP-3, all subjects in this study were alive without clinical evidence of cancer during their 5th year of the cohort follow-up. Four hundred randomly selected cohort controls and 93 incident pancreatic adenocarcinoma cases that occurred between their 5th follow-up year through 1997 (i.e., up to 12.7 years of follow-up) were included in this study. Concentrations of IGF-1 and IGFBP-3 were measured in serum samples obtained at baseline using ELISA. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models, adjusted for confounders. Neither IGF-1, IGFBP-3, nor the IGF-1:IGFBP-3 molar ratio was significantly associated with pancreatic cancer: highest compared to lowest tertile, OR = 0.67, 95% CI 0.37-1.21, P trend = 0.17; OR = 0.70, 95% CI 0.38-1.27, P trend = 0.12; and OR = 0.85, 95% CI 0.50-1.46, P trend = 0.54, respectively. Our results do not support the hypothesis that serum IGF-1 and IGFBP-3 concentrations are associated with pancreatic cancer risk among male smokers. Further studies are necessary to evaluate these associations in other populations. 相似文献
29.
Nutritional predictors of insulin-like growth factor I and their relationships to cancer in men. 总被引:4,自引:0,他引:4
Edward Giovannucci Michael Pollak Yan Liu Elizabeth A Platz Noreen Majeed Eric B Rimm Walter C Willett 《Cancer epidemiology, biomarkers & prevention》2003,12(2):84-89
The insulin-like growth factor (IGF) axis may play opposing roles in health and disease.The age-related declines in growth hormone and IGF-I may be associated with potentially deleterious changes in body composition and functioning, but recent studies suggest that IGF-I levels may be related to risk of prostate, colorectal, premenopausal breast, and possibly other cancers. Thus, we studied dietary influences on plasma IGF-I and IGF-I:IGF-binding protein-3 ratio in 753 men in the Health Professionals Follow-Up Study who completed a food frequency questionnaire. In this generally well-nourished population of middle-aged to elderly men, plasma IGF-I and IGF-I:IGF-binding protein-3 molar ratio tended to increase with higher intake of protein and minerals, including potassium, zinc, magnesium, calcium, and phosphorus. Men with relatively high intakes of total protein (top quintile) and minerals (top quintile of the five minerals combined) had a 25% higher mean plasma level of IGF-I compared with those in the low quintiles simultaneously. The major sources of animal protein, including milk, fish, and poultry, but not red meat, as well as total vegetable protein, were associated with an increase in IGF-I levels. Energy intake was positively related to plasma IGF-I level but only in men with body mass index <25 kg/m(2). The age-related decline in plasma IGF-I may be exacerbated by low intakes of protein and minerals. The potential role of these dietary factors on cancer risk through altering IGF-I levels requires study. 相似文献
30.
Orthopaedic manifestations of familial dysautonomia. A review of one hundred and thirty-six patients
Bar-On E Floman Y Sagiv S Katz K Pollak RD Maayan C 《The Journal of bone and joint surgery. American volume》2000,(11):1563-1570
BACKGROUND: Familial dysautonomia is a hereditary multisystemic disease primarily affecting people of Ashkenazi Jewish descent. Musculoskeletal problems are related to gait disorders, spinal deformities, foot deformities, fractures, and arthropathies. METHODS: The charts and radiographs of 136 patients who ranged in age from three months to forty-six years (mean, sixteen years) were reviewed. Sixty-four patients were available for follow-up examination. RESULTS: Spinal deformity was the most common orthopaedic problem and was diagnosed in seventy-eight patients starting at the age of four years, with a prevalence of 86 percent (forty-eight of fifty-six) by the age of fifteen years. Forty-one (53 percent) of the seventy-eight patients had scoliosis only, thirty-four (44 percent) had kyphoscoliosis, and three (4 percent) had kyphosis only. Bracing was accompanied by emotional, pulmonary, and skin problems, leading to a high rate of noncompliance and progression of the curve. Twenty-four patients had an operation at a mean age of thirteen years (range, five to eighteen years): twenty patients had posterior spinal arthrodesis, and four had combined anterior and posterior arthrodesis. Fifteen patients had a total of nineteen complications, of which seven were systemic and twelve were related to the spinal fixation. Eight patients had revision surgery. At the time of the surgery, scoliosis was corrected from a mean of 55 degrees to a mean of 35 degrees and kyphosis was corrected from a mean of 69 degrees to a mean of 61 degrees. After a mean duration of follow-up of sixty-five months, scoliosis measured 49 degrees (range, 18 to 62 degrees) and kyphosis measured 67 degrees (range, 30 to 115 degrees). Postoperative progression of the deformity was caused by failure of the instrumentation or progression in unfused segments. Walking was delayed in 72 percent (ninety-four) of the 130 patients who were of walking age. All sixty-four of the patients who were examined had an ataxic gait. Foot deformities were found in sixteen patients, six of whom were treated surgically. Two patients had Charcot joints. Fifty-five patients sustained at least one fracture before skeletal maturity, with a mean of 1.5 fractures per patient. All but one of the fractures was treated nonoperatively, and fracture-healing was often accompanied by profuse callus formation. CONCLUSIONS: Spinal deformity is common in patients with familial dysautonomia. Bracing is of questionable benefit, and surgical intervention should be considered once curve progression is well documented. Arthrodesis should be extended as far proximally as possible to prevent junctional kyphosis. Swelling and warmth in a limb should raise suspicion of an undiagnosed fracture. 相似文献