全文获取类型
收费全文 | 8124篇 |
免费 | 610篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 131篇 |
儿科学 | 252篇 |
妇产科学 | 238篇 |
基础医学 | 1170篇 |
口腔科学 | 112篇 |
临床医学 | 851篇 |
内科学 | 1773篇 |
皮肤病学 | 111篇 |
神经病学 | 750篇 |
特种医学 | 192篇 |
外科学 | 915篇 |
综合类 | 135篇 |
一般理论 | 9篇 |
预防医学 | 822篇 |
眼科学 | 66篇 |
药学 | 523篇 |
中国医学 | 12篇 |
肿瘤学 | 685篇 |
出版年
2023年 | 71篇 |
2022年 | 102篇 |
2021年 | 200篇 |
2020年 | 116篇 |
2019年 | 212篇 |
2018年 | 248篇 |
2017年 | 157篇 |
2016年 | 178篇 |
2015年 | 212篇 |
2014年 | 270篇 |
2013年 | 399篇 |
2012年 | 574篇 |
2011年 | 574篇 |
2010年 | 314篇 |
2009年 | 249篇 |
2008年 | 416篇 |
2007年 | 423篇 |
2006年 | 405篇 |
2005年 | 359篇 |
2004年 | 336篇 |
2003年 | 308篇 |
2002年 | 300篇 |
2001年 | 176篇 |
2000年 | 174篇 |
1999年 | 155篇 |
1998年 | 75篇 |
1997年 | 53篇 |
1996年 | 54篇 |
1995年 | 52篇 |
1994年 | 60篇 |
1993年 | 42篇 |
1992年 | 117篇 |
1991年 | 122篇 |
1990年 | 94篇 |
1989年 | 101篇 |
1988年 | 103篇 |
1987年 | 93篇 |
1986年 | 93篇 |
1985年 | 75篇 |
1984年 | 51篇 |
1983年 | 48篇 |
1982年 | 34篇 |
1981年 | 30篇 |
1980年 | 32篇 |
1979年 | 66篇 |
1978年 | 50篇 |
1976年 | 34篇 |
1974年 | 32篇 |
1970年 | 26篇 |
1966年 | 26篇 |
排序方式: 共有8747条查询结果,搜索用时 15 毫秒
31.
A theoretical model of prevention addressing adolescents at-risk of offending was developed then utilised to assess a primary and secondary prevention program. The study of the wilderness-based practise was conducted between September 1992 and October 1994, adopting a pre-post-follow-up quasi-experimental design using waiting periods to establish treatment and control groups. Maturational changes were gauged over a 12 month period of 44 male and 18 female voluntary Australian adolescents between the ages of 15 and 25 years. Significant differences between the treatment and control groups in the psychometric areas of general self-esteem and self-actualisation were found establishing positive program effect on participants. Further, the long term effect of this program in preventing participants initial contact with court proceedings or reducing further involvement respectively, over a twelve month period was substantiated. It was shown that following this experience post program goals of employment and education for adolescents at-risk were positively influenced. 相似文献
32.
OBJECTIVE AND DESIGN: Neutrophil-derived hypochlorous acid (PMN-HOCL) is a potent bactericidal and fungicidal agent. Neutrophils from patients with multiple organ failure (MOF) have an altered ability to inhibit Candida albicans. Conversely antifungal agents are effective in decreasing mortality in MOF patients with fungaemia. We determined the effect on the rate of production of PMN-HOCL in a series of MOF patients with C. albicans fungaemia when antifungal agents are administered. SUBJECTS AND METHODS: Eleven patients with MOF were recruited. Four patients had culture-positive C. albicans fungaemia (group 1) and 7 patients with MOF but without C. albicans fungaemia acted as controls (group 2). HOCL assays were performed on peripheral blood PMN obtained from group 1 and group 2 patients. RESULTS: The maximum PMN-HOCL production rate for group 1 increased from 0.24 nmol/million PMN/min to 0.8 nmol/million PMN/min after treatment with antifungal agents (p < 0.01) (Mann-Whitney U test) whereas the PMN-HOCL kinetic (rate) curves for group 1 post-treatment and for group 2 were similar (student's-t-test). CONCLUSIONS: These findings suggest that antifungal treatment improve PMN-HOCL production in MOF patients with C. albicans fungaemia and may improve the effectiveness in eradicating the organism. 相似文献
33.
Julie D Rippeth Robert K Heaton Catherine L Carey Thomas D Marcotte David J Moore Raul Gonzalez Tanya Wolfson Igor Grant 《Journal of the International Neuropsychological Society》2004,10(1):1-14
Both HIV infection and methamphetamine dependence can be associated with brain dysfunction. Little is known, however, about the cognitive effects of concurrent HIV infection and methamphetamine dependence. The present study included 200 participants in 4 groups: HIV infected/methamphetamine dependent (HIV+/METH+), HIV negative/methamphetamine dependent (HIV-/METH+), HIV infected/methamphetamine nondependent (HIV+/METH-), and HIV negative/methamphetamine nondependent (HIV-/METH-). Study groups were comparable for age, education, and ethnicity, although the HIV-/METH- group had significantly more females. A comprehensive, demographically corrected neuropsychological battery was administered yielding a global performance score and scores for seven neurobehavioral domains. Rates of neuropsychological impairment were determined by cutoff scores derived from performances of a separate control group and validated with larger samples of HIV+ and HIV- participants from an independent cohort. Rates of global neuropsychological impairment were higher in the HIV+/METH+ (58%), HIV-/METH+ (40%) and HIV+/METH- (38%) groups compared to the HIV-/METH- (18%) group. Nonparametric analyses revealed a significant monotonic trend for global cognitive status across groups, with least impairment in the control group and highest prevalence of impairment in the group with concurrent HIV infection and methamphetamine dependence. The results indicate that HIV infection and methamphetamine dependence are each associated with neuropsychological deficits, and suggest that these factors in combination are associated with additive deleterious cognitive effects. This additivity may reflect common pathways to neural injury involving both cytotoxic and apoptotic mechanisms. 相似文献
34.
Social learning theory-based models have recently provided the foundation for a series of twelve controlled human immunodeficiency virus (HIV) risk reduction intervention studies that have examined sexual behavior change. These interventions have been tested with adolescents, gay and bisexual men, inner-city women, college students, and seriously mentally ill adults. We report the first meta-analysis of these intervention studies. We found that, as expected, the mean weighted effect of HIV-risk reduction interventions on behavioral outcomes was positive and strongly significant (d+=0.25). Moreover, the studies’ effect sizes were consistently positive, ranging from 0.11 to 0.53, and were largest when the outcomes were measured close in time to the intervention. We discuss other methodological challenges that, if solved, should enhance the success of future HIV-risk reduction interventions. 相似文献
35.
1. Subepidermal injection of histamine solutions in isotonic saline in four subjects evoked whealing after a mean delay of 2.6 min, this estimate being derived by regression modelling. 2. Wheal growth was better modelled by the logarithm of time than by time, suggesting that wheal size depends upon assisted diffusion of histamine in the dermis. 3. Wheal growth was piecemeal, not continuous, consistent with the successive involvement of neighbouring vascular territories. 4. Wheal growth was completed by 9 min after injection. 相似文献
36.
G Luppino M Matelli R G Carey D Fitzpatrick I T Diamond 《The Journal of comparative neurology》1988,273(1):67-86
The projections of the superficial layers of the superior colliculus to the pulvinar nucleus in Tupaia were reexamined by injecting WGA-HRP into the tectum. The main result was finding two different patterns of terminations in the pulvinar nucleus: a zone remote from the lateral geniculate nucleus, which occupies the dorsomedial and caudal poles of the pulvinar nucleus, was almost entirely filled with terminals in every case irrespective of the location of the injection site; and a second division of the pulvinar nucleus, adjacent to the lateral geniculate nucleus, contained irregular patches--much more densely populated--and the distribution of patches varied from case to case. We call the first projection "diffuse" and the patchy projection "specific." Next we injected several divisions of the extrastriate visual cortex to find the cortical target of each pathway. The diffuse path terminates in the ventral temporal area (Tv). The specific path terminates in the dorsal temporal area (Td) and area 18. We speculated about the significance of the two pathways: the specific path may be responsible for the preservation of vision after removal of the striate cortex; the diffuse path may have an important place in the evolution of the visual areas of the temporal and occipital lobe. We argued that the target of the diffuse path is in a position to relate limbic and visual impulses and relay the product of such integration to the other visual areas, striate as well as extrastriate cortex. 相似文献
37.
38.
39.
F Fiacchino M Bricchi M Gemma B Regi M Montolivo M T Crippa C Ferrazza E Bruzzone 《Minerva anestesiologica》1989,55(1-2):11-19
Pre- and postoperative serum CK activity is evaluated in 142 children submitted, "uneventfully", to diagnostic muscle biopsy under halothane (77 patients), ketamine (50 patients) or "local" (15 patients) anaesthesia. The purpose was to ascertain whether or not anaesthesia-induced-rhabdomyolysis (AR) was an asymptomatic (and unrecognized) complication of "uneventful" anaesthesia. The majority of patients with low preoperative CK values showed a slight increase of serum CK activity on the first postoperative day. On the contrary, a postoperative decrease was observed in the majority of patients with high preoperative values (namely in almost all ketamine patients and in 2/3 of halothane-patients). In no case postoperative increase reached a value suggesting the occurrence of AR even though a postoperative value of 16480 U/I was observed in a patient with Duchenne muscular dystrophy after halothane anaesthesia. Sudden interruption of motor activity induced by general anaesthesia seems to be the most important factor in reducing the release of CK from muscle. When preoperative release is low, any further postoperative reduction is not sufficient to balance the moderate increase of CK produced by the surgical procedure; the opposite should happen in patients presenting with high preoperative release. So far as anaesthetics are concerned, our data seem to suggest that ketamine has a higher "protective" role compared to halothane. 相似文献
40.
P V Nelson W F Carey C P Morris A C Pollard 《The Medical journal of Australia》1989,151(3):126-7, 130-1
The analysis of restriction fragment length polymorphism (RFLP)s was used to detect 11 polymorphisms that are linked to cystic fibrosis in 42 Australian families with at least one child with cystic fibrosis. The data from all the families were fully informative in regard to the gene for cystic fibrosis (CF). Prenatal assessment was performed for 24 of these families: seven fetuses were assessed to be homozygous for cystic fibrosis, 13 fetuses were heterozygous and three fetuses were free of the CF gene. Of the seven pregnancies in which it was predicted that the infant would be affected by cystic fibrosis, two were continued electively; both have come to term and the infants each were shown to have cystic fibrosis at birth. Of the 17 pregnancies in which it was predicted that the infant would not be affected by cystic fibrosis, 13 have come to term and all the infants but one (who has not yet been followed-up) have been shown to be unaffected by cystic fibrosis at birth. The polymerase chain reaction has been used to amplify the CS.7 and KM.19 loci close to the CF gene. This procedure allows a polymorphic site in each locus to be analysed in a much shorter time (one or two days rather than 10 days) and allows the use of very small test-samples, such as dried blood on filter paper ("Guthrie blood spots"). Our observations confirm the results of overseas studies and indicate that these techniques are eminently useful for prenatal diagnosis and the detection of carriers in the vast majority of Australian families with cystic fibrosis. 相似文献