全文获取类型
收费全文 | 38393篇 |
免费 | 2917篇 |
国内免费 | 117篇 |
专业分类
耳鼻咽喉 | 292篇 |
儿科学 | 1447篇 |
妇产科学 | 1181篇 |
基础医学 | 5342篇 |
口腔科学 | 533篇 |
临床医学 | 4915篇 |
内科学 | 7284篇 |
皮肤病学 | 692篇 |
神经病学 | 3996篇 |
特种医学 | 942篇 |
外科学 | 3768篇 |
综合类 | 510篇 |
一般理论 | 34篇 |
预防医学 | 4552篇 |
眼科学 | 726篇 |
药学 | 2300篇 |
中国医学 | 203篇 |
肿瘤学 | 2710篇 |
出版年
2023年 | 271篇 |
2022年 | 494篇 |
2021年 | 1015篇 |
2020年 | 629篇 |
2019年 | 1021篇 |
2018年 | 1117篇 |
2017年 | 784篇 |
2016年 | 896篇 |
2015年 | 933篇 |
2014年 | 1323篇 |
2013年 | 1958篇 |
2012年 | 2883篇 |
2011年 | 2955篇 |
2010年 | 1629篇 |
2009年 | 1363篇 |
2008年 | 2359篇 |
2007年 | 2579篇 |
2006年 | 2518篇 |
2005年 | 2402篇 |
2004年 | 2126篇 |
2003年 | 1987篇 |
2002年 | 1912篇 |
2001年 | 464篇 |
2000年 | 394篇 |
1999年 | 456篇 |
1998年 | 409篇 |
1997年 | 367篇 |
1996年 | 293篇 |
1995年 | 287篇 |
1994年 | 220篇 |
1993年 | 269篇 |
1992年 | 276篇 |
1991年 | 242篇 |
1990年 | 208篇 |
1989年 | 217篇 |
1988年 | 212篇 |
1987年 | 170篇 |
1986年 | 152篇 |
1985年 | 149篇 |
1984年 | 140篇 |
1983年 | 118篇 |
1982年 | 97篇 |
1981年 | 95篇 |
1980年 | 106篇 |
1979年 | 90篇 |
1978年 | 103篇 |
1977年 | 68篇 |
1976年 | 58篇 |
1972年 | 66篇 |
1971年 | 54篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
George Karpati Djordje Ajdukovic Douglas Arnold Robert B. Gledhill Ronald Guttmann Paul Holland Penelope A. Koch Eric Shoubridge Desmond Spence Michel Vanasse Gordon V. Watters Michael Abrahamowicz Catherine Duff Ronald G. Worton 《Annals of neurology》1993,34(1):8-17
One biceps muscle of 8 patients with Duchenne muscular dystrophy was injected at 55 sites with a total of 55 million viable, purified, and contamination-free normal myoblasts (myoblast transfer). The other biceps of each patient was injected with a placebo to serve as a control. The procedure was blinded to the patients, parents, and investigators. Myoblasts derived from a biopsy specimen of the fathers were cultured and purified under strict conditions and carefully screened for microbial contamination. All patients received cyclophosphamide for immunosuppression for 6 or 12 months. No serious complications were observed after myoblast transfer, indicating that the procedure is safe. The overall therapeutic efficiency of myoblast transfer was poor as judged by the results in maximal voluntary force generation, dystrophin content of the muscle, magnetic resonance imaging of the muscle, and the lack of donor-derived DNA and dystrophin messenger RNA in the injected muscle. An improved efficiency of the take of myoblasts might be achieved by using younger cells and injecting the myoblasts with a myonecrotic agent (to increase the prevalence of regeneration) and a basal laminal fenestrating agent. 相似文献
103.
104.
N F Hopkins I S Benjamin M H Thompson R C Williamson 《Annals of the Royal College of Surgeons of England》1990,72(4):229-235
Choledochal cyst is a well-recognised entity, presenting primarily in infants and young children. Where symptoms are delayed until adulthood, associated hepatobiliary pathology may complicate the presentation. These problems may be aggravated by previous treatment with bypass surgery rather than resection. We report seven cases from our recent experience presenting with complications in adulthood. These included cholangitis, hepatic abscess, pancreatitis and malignancy within the cyst. Two patients presented during pregnancy. These complications and their implications for management are discussed. 相似文献
105.
Lynn McIntyre Edwin G. Belzer Lise Manchester Wade Blanchard Suzanne Officer A. Catherine Simpson 《The Journal of school health》1996,66(3):132-137
ABSTRACT: The Dartmouth Health Promotion Study was a longitudinal, quasi-experimental field study with a qualitative research arm, designed to learn whether coordinating school health instruction, health services, and a healthful environment enhanced the program's effect on the heart health and mental health of children. The research strategy — the Coordinated Approach — was applied to approximately 300 children in each of two cohorts in grades four to six attending nine trial schools; a further 600 children attended 10 comparison schools in Dartmouth and nine distal comparison schools. Although the qualitative analysis demonstrated that positive feelings were engendered in most areas of the study, when either the classroom or the individual was used as the unit of analysis, the Coordinated Approach did not have a more favorable effect on the heart or mental health of children than did the standard school health program. Thus, the effect of an existing school health program was not directly enhanced through coordinating its components. 相似文献
106.
Data concerning the food and beverage intake (including alcohol) of 79 males, aged 19–50 years, sleeping rough in Central London, who did not appear to be under the influence of drink, drugs or suffering from mental illness were collected by prompted 24-h recall and food-frequency questionnaire (FFQ). The source of food was noted and the subjects were asked about food availability and food needs. The group had intakes significantly lower than Dietary Reference Values (DRV) for the UK for energy, carbohydrate, non-starch polysaccharides (NSP), folate, zinc and magnesium. Significantly higher values were seen for protein, fat, vitamin B12 , calcium and iron. Alcohol intake was higher than that assumed to approximate current intakes of the UK population. Mean macronutrient intakes for the group were similar to means for British adult men (OPCS, 1990), only protein and NSP were significantly lower. The FFQ showed very low consumption/week of fruit, vegetables, salad, fruit juice and wholewheat/brown products. Organized charities provided the major source of food energy for the group as a whole. Self-supplied sources provided the major source of total energy. It is suggested that the group may benefit from an increase in dietary fibre and energy, with an increase in the proportion of energy supplied by carbohydrate and a reduction in energy from fat and alcohol. A varied supply of food and hot meals during weekends as well as during the week may benefit the group both aesthetically and nutritionally. It may be advisable to increase the supply of wholemeal/brown bread, fruits, vegetables and salad foods without decreasing the energy content of the food available. 相似文献
107.
108.
John M. Meredith Catherine J. Auger Jeffrey D. Blaustein 《Journal of neuroendocrinology》1994,6(6):639-648
Low amplitude pulses of estradiol-17β (E2-17β) are more effective than large single bolus injections or constant exposure to E2-17β in inducing progesterone-facilitated sex behavior in female rats and guinea pigs. The present study examined whether the increased responsiveness to E2-17β is due to an increase in the number of estrogen receptors in the estrogen receptor rich areas of the hypothalamus and amygdala. Initial studies examined the rapid effects (20 min) of a high dose of E2-17β (50 μg) on estrogen receptor immunostaining using either the H222 antibody or the ER 21 antiserum. ER 21 immunostaining was not affected by the E2-17β treatment suggesting that it binds to both occupied and unoccupied estrogen receptors. Therefore the ER 21 antiserum was used to characterize the regulation of estrogen receptor immunoreactivity (ER-IR) by E2-17β. ER-IR was examined for 48 h and serum E2-17β for 24 h following a 2 μg s.c. injection of E2-17β (a dose similar to that used in multiple pulse paradigms). Serum E2-17β peaked 15 to 30 min following the injection and returned to baseline values by 1 h. In all but one area maximal suppression of ER-IR occurred at 12 h. In summary, 1) decreases in estrogen receptor immunoreactivity following E2-17β are consistent with studies in which estrogen receptors were assayed by binding assays and estrogen receptor mRNA was determined by in situ hybridization; 2) the ER 21 antiserum is able to detect both occupied and unoccupied estrogen receptors and 3) H222 immunoreactivity is influenced by the presence of E2-17β, so that the level of H222-IR is a reflection of ligand/receptor binding dynamics. The data suggest that up-regulation of estrogen receptors does not account for the increase in behavioral sensitivity which is observed following multiple pulses of E2-17β. 相似文献
109.
110.
I. J. Williamson A. Reid R. D. Monie A. G. Fennerty E. M. Rimmer 《Postgraduate medical journal》1997,73(857):156-158
Generic substitution of salbutamol lags behind that of other drugs in Scotland and a negative perception by both patients and doctors may explain this. The aim of this study was to assess whether, in clinical practice, there was any difference in efficacy between branded salbutamol (Ventolin) and a generic preparation. Asthmatic patients using a Ventolin metered-dose inhaler at least twice a day for symptom relief were entered into a double-blind cross-over study, comparing Ventolin, blinded Ventolin and a generic salbutamol in random order for two weeks each. Daily peak flows, inhaler use and bronchodilator response were recorded. At the end of each treatment period patients rated their inhaler against their usual Ventolin on a 5-point scale. Forty patients were entered into the study; 90% received 1000 micrograms or more of inhaled steroids per day. Eleven patients dropped out during the run-in phase. In the remaining 29 patients, no significant difference between treatments could be found in any of the objective parameters measured. Fifty-five per cent of patients said they could detect a difference between the inhalers, and 45% noted a difference between their usual Ventolin and the open or blinded Ventolin. This study showed clinical equivalence between a generic and branded salbutamol. Patients'' own assessment of their relief inhaler seems to be influenced by factors other than efficacy. The study highlights that careful encouragement is required when changing to a generic product and has particular implications for the forthcoming conversion to CFC-free products. 相似文献