全文获取类型
收费全文 | 1598篇 |
免费 | 134篇 |
国内免费 | 60篇 |
专业分类
耳鼻咽喉 | 23篇 |
儿科学 | 87篇 |
妇产科学 | 29篇 |
基础医学 | 188篇 |
口腔科学 | 54篇 |
临床医学 | 207篇 |
内科学 | 381篇 |
皮肤病学 | 23篇 |
神经病学 | 126篇 |
特种医学 | 157篇 |
外科学 | 188篇 |
综合类 | 34篇 |
一般理论 | 3篇 |
预防医学 | 81篇 |
眼科学 | 22篇 |
药学 | 98篇 |
中国医学 | 2篇 |
肿瘤学 | 89篇 |
出版年
2021年 | 14篇 |
2019年 | 13篇 |
2018年 | 16篇 |
2016年 | 16篇 |
2015年 | 25篇 |
2014年 | 36篇 |
2013年 | 58篇 |
2012年 | 42篇 |
2011年 | 42篇 |
2010年 | 40篇 |
2009年 | 46篇 |
2008年 | 65篇 |
2007年 | 109篇 |
2006年 | 56篇 |
2005年 | 59篇 |
2004年 | 40篇 |
2003年 | 32篇 |
2002年 | 31篇 |
2001年 | 42篇 |
2000年 | 34篇 |
1999年 | 33篇 |
1998年 | 37篇 |
1997年 | 46篇 |
1996年 | 27篇 |
1995年 | 28篇 |
1994年 | 38篇 |
1993年 | 29篇 |
1992年 | 34篇 |
1991年 | 41篇 |
1990年 | 33篇 |
1989年 | 51篇 |
1988年 | 41篇 |
1987年 | 31篇 |
1986年 | 26篇 |
1985年 | 42篇 |
1984年 | 23篇 |
1983年 | 29篇 |
1982年 | 20篇 |
1981年 | 22篇 |
1980年 | 24篇 |
1979年 | 33篇 |
1978年 | 26篇 |
1977年 | 27篇 |
1976年 | 31篇 |
1975年 | 31篇 |
1974年 | 16篇 |
1973年 | 14篇 |
1972年 | 15篇 |
1971年 | 24篇 |
1970年 | 22篇 |
排序方式: 共有1792条查询结果,搜索用时 15 毫秒
21.
Diverse cardiovascular responses to aortic constriction in normotensive Sprague-Dawley versus spontaneously hypertensive rats. 下载免费PDF全文
B. C. Wexler 《The American journal of pathology》1979,97(3):549-561
Normotensive, Sprague-Dawley (S-D) and spontaneously hypertensive (SH) rats were subjected to aortic ligature. The systolic blood pressure of S-D rats was increased by +/- 80 mm Hg, whereas the blood pressure of SH rats with pre-existent hypertension increased only slightly, +/- 9 mm Hg. The S-D rats developed myocardial and renal infarcts as well as polyarteritis nodosa; the SH rats developed testicular and microadrenocortical infarcts only. Aortic-ligated S-D rats had elevated creatine phosphokinase, serum glutamic-oxaloacetic transaminase, serum glutamic-pyruvic transaminase, and lactic hydrogenase levels and manifested hyperglycemia, hypercholesterolemia, and elevated blood urea nitrogen (BUN) levels. Corticosterone levels increased in aortic-ligated S-D rats but decreased in SH rats. Collateralization about the site of aortic ligature appeared to be the same in both strains. It is suggested that the acutely induced hypertension in S-D rats rather than SH rats and differences in adrenal steroidogenesis between the two strains would best account for the dichotomous cardiovascular response to aortic constriction. 相似文献
22.
Although in physics, quantum mechanical principles have long replaced Newtonian ones, we continue to apply the latter in models of the mind and its diseases. This article discusses the possible theoretical application of quantum principles to mind-brain function. Empirically, this study tested which of these principles practicing psychiatrists found more applicable in clinical practice. Psychiatrists (N = 382) at universities around the United States were asked to answer a questionnaire that contained clinical scenarios reflecting mental, interpersonal, or therapeutic processes corresponding to quantum or classical physical principles. Respondents (N = 191) were significantly more likely to rate scenarios reflecting quantum principles as being consistent with their experience than they were those reflecting classical principles (p < .0005). This effect was significantly greater in more experienced psychiatrists. Quantum physics, a powerful tool in understanding properties of both micro- and macro-level phenomena, may have implications at the human level, invoking the roles of observer, interpersonal relationships, and resources such as resiliency and creativity. 相似文献
23.
Olson RE Sielecki TM Wityak J Pinto DJ Batt DG Frietze WE Liu J Tobin AE Orwat MJ Di Meo SV Houghton GC Lalka GK Mousa SA Racanelli AL Hausner EA Kapil RP Rabel SR Thoolen MJ Reilly TM Anderson PS Wexler RR 《Journal of medicinal chemistry》1999,42(7):1178-1192
Modification of the alpha-carbamate substituent of isoxazoline GPIIb/IIIa (alphaIIb beta3) antagonist DMP 754 (7) led to a series of alpha-sulfonamide and alpha-sulfamide diaminopropionate isoxazolinylacetamides which were found to be potent inhibitors of in vitro platelet aggregation. Aryl- and heteroaryl-alpha-sulfonamide groups, in conjunction with (5R)-isoxazoline (2S)-diaminopropionate stereochemistry, were found to impart a pronounced duration of antiplatelet effect in dogs, potentially due to high affinity for unactivated platelets. Isoxazolylsulfonamide 34b (DMP 802), a highly selective GPIIb/IIIa antagonist, demonstrated a prolonged duration of action after iv and po dosing and high affinity for resting and activated platelets. The prolonged antiplatelet profile of DMP 802 in dogs and the high affinity of DMP 802 for human platelets may be predictive of clinical utility as a once-daily antiplatelet agent. 相似文献
24.
OBJECTIVES: To determine the spectrum of N and G genotypes of respiratory syncytial virus (RSV) causing respiratory tract infection and whether particular genotypes are associated with severity of infection. PATIENTS AND METHODS: Nasopharyngeal aspirates (NPAs) were obtained from 114 infants with acute respiratory tract infection due to RSV over two seasons. Viral mRNA was extracted from NPAs or cultured virus, reverse transcribed, and the cDNA amplified by the polymerase chain reaction using primers directed to parts of the N and G gene respectively. Amplicons were separately digested with four different restriction endonucleases for each gene. The fragments were separated by agarose gel, electrophoresis, and the electrophoretic patterns used to assign the various genotypes. Disease severity was assessed as very mild (upper respiratory tract signs only), mild (coryza and signs of lower respiratory tract infection), moderate (requiring nasogastric or intravenous fluids), and severe (requiring oxygen or ventilation). RESULTS: Five of the six known N genotypes were detected, but NP4 and NP2 were found most frequently. There was no association between N genotype and disease severity. Six G (SHL) genotypes were detected. Significantly (p = 0.04) more of the infants infected with the SHL2 genotype had severe or moderate disease. CONCLUSIONS: During the seasonal peaks of RSV respiratory tract infection at least 10 different RSV genotypes cocirculated. While there is no association between N genotypes and disease severity, infection with the SHL2 G genotype appears to result in moderate to severe disease. 相似文献
25.
Shpichinetsky V Raz I Friedlander Y Goldschmidt N Wexler ID Ben-Yehuda A Friedman G 《The Journal of nutrition》2000,130(10):2493-2497
Mutations of the methylenetetrahydrofolate reductase (MTHFR) gene have been shown to be associated with a predisposition to developing diabetic nephropathy (DN) in specific populations. The frequency of two MTHFR mutations, a recently described mutation in the human MTHFR gene A1298C and C677T, whose association with DN is already known, was determined in an Israeli Jewish population with type 2 diabetes mellitus (DM). Both A1298C and C677T are highly prevalent in the diabetic population with allele frequencies of 0.35 and 0.36, respectively. The genotype frequency and allele frequency for these two polymorphisms in patients who are normoalbuminuric (n = 55) were compared with those of patients who had either micro- or macroalbuminuria (n = 43). For both polymorphisms, there were no significant differences in either the genotype distribution or allele frequency in patients with or without DN. However, in patients with serum folate <15.4 nmol/L, there was a greater incidence of DN in those patients who were homozygous or heterozygous for the C677T mutation. For the A1298C mutation, there is evidence suggesting that the homozygous state may be protective in patients with low-normal serum folate. Folate supplementation in diabetic patients with the C677T mutation and low-normal serum folate may prevent the onset or retard the progression of DN. 相似文献
26.
Illes J Glover GH Wexler L Leung AN Glazer GM 《Academic radiology》2000,7(9):717-24; discussion 725-6
RATIONALE AND OBJECTIVES: The purpose of this report is to describe the development and implementation of a faculty mentoring program in radiology designed to promote the career development of junior faculty and enhance communication in the department. MATERIALS AND METHODS: The mentoring program was implemented in five stages: organizational readiness, participant recruitment, mentor matching and orientation, implementation, and evaluation. Evaluations were based on Likert scale ratings and qualitative feedback. A retrospective analysis was also conducted of the annual performance reviews of junior faculty in the areas of research, teaching, patient care, and overall performance. RESULTS: An average of 83% (19 of 23) of the junior faculty participated in the pilot phase of the mentoring program. During five rounds of testing, the median rating (1 indicates not important; 10, extremely important) from responding junior faculty was 10 for overall value of individual mentoring meetings; the median rating for the mentors responding was 8.75. Research and academic development were identified as the areas of greatest importance to the faculty. Research and patient care were most improved as assessed by faculty peers during performance reviews. The schedule of semiannual formal mentoring meetings was reported to be optimal. CONCLUSION: The program was implemented to the satisfaction of junior faculty and mentors, and longitudinal performance suggests positive effects. Issues to be contended with include confidentiality and the time needed for mentoring beyond already saturated schedules. Overall, the authors propose that mentoring programs can be an asset to academic radiology departments and a key factor in maintaining their vitality. 相似文献
27.
Effect of posaconazole on cytochrome P450 enzymes: a randomized, open-label, two-way crossover study 总被引:3,自引:0,他引:3
D. Wexler R. Courtney W. Richards C. Banfield J. Lim M. Laughlin 《European journal of pharmaceutical sciences》2004,21(5):139-653
Posaconazole is an antifungal with a wide-spectrum of activity against common and emerging fungal pathogens. In this randomised, open-label, two-way crossover study, the potential for drug interactions with posaconazole via the cytochrome P450 (CYP450) enzyme pathway was evaluated. Thirteen subjects received posaconazole tablets (2×100 mg) once daily for 10 days or no treatment; following a 14-day washout period, subjects were crossed over to the alternate treatment. The inhibition spectra of posaconazole were examined using a cocktail of the following probe substrates: caffeine (CYP1A2), tolbutamide (CYP2C8/9), dextromethorphan (CYP2D6 and total CYP3A4), chlorzoxazone (CYP2E1), and midazolam (hepatic CYP3A4). Except for midazolam, which was intravenously infused on Day 10, the cocktail probes were administered simultaneously on Day 9 during both treatment periods. Blood and urine samples were collected at specified times to quantitate probe substrates and/or metabolites. Based on insignificant differences in mean probe ratios, posaconazole did not inhibit CYP1A2, 2C8/9, 2D6, or 2E1. However, the midazolam AUC(tf) was higher in the posaconazole than no-treatment group (93.4 ng h/ml versus 51.4 ng h/ml, P<0.01), indicating inhibition of hepatic CYP3A4. Drug interactions mediated by various CYP450 are common with the currently available triazole antifungals, however these results suggest that posaconazole may have an improved and more narrow drug interaction profile (CYP3A4 only) compared with other triazoles. 相似文献
28.
Marielle E. Yohe Christine M. Heske Elizabeth Stewart Peter C. Adamson Nabil Ahmed Cristina R. Antonescu Eleanor Chen Natalie Collins Alan Ehrlich Rene L. Galindo Berkley E. Gryder Heidi Hahn Sharon Hammond Mark E. Hatley Douglas S. Hawkins Madeline N. Hayes Andrea Hayes‐Jordan Lee J. Helman Simone Hettmer Myron S. Ignatius Charles Keller Javed Khan David G. Kirsch Corinne M. Linardic Philip J. Lupo Rossella Rota Jack F. Shern Janet Shipley Sivasish Sindiri Stephen J. Tapscott Christopher R. Vakoc Leonard H. Wexler David M. Langenau 《Pediatric blood & cancer》2019,66(10)
Overall survival rates for pediatric patients with high‐risk or relapsed rhabdomyosarcoma (RMS) have not improved significantly since the 1980s. Recent studies have identified a number of targetable vulnerabilities in RMS, but these discoveries have infrequently translated into clinical trials. We propose streamlining the process by which agents are selected for clinical evaluation in RMS. We believe that strong consideration should be given to the development of combination therapies that add biologically targeted agents to conventional cytotoxic drugs. One example of this type of combination is the addition of the WEE1 inhibitor AZD1775 to the conventional cytotoxic chemotherapeutics, vincristine and irinotecan. 相似文献
29.
30.
Arianne C Lim Kitty WM Bloemenkamp Kees Boer Johannes J Duvekot Jan Jaap HM Erwich Tom HM Hasaart Pieter Hummel Ben WJ Mol Jos PM Offermans Charlotte M van Oirschot Job G Santema Hubertina CJ Scheepers Willem A Schöls Frank PHA Vandenbussche Maurice GAJ Wouters Hein W Bruinse 《BMC pregnancy and childbirth》2007,7(1):1-6