全文获取类型
收费全文 | 33389篇 |
免费 | 1998篇 |
国内免费 | 333篇 |
专业分类
耳鼻咽喉 | 550篇 |
儿科学 | 349篇 |
妇产科学 | 462篇 |
基础医学 | 5563篇 |
口腔科学 | 875篇 |
临床医学 | 2675篇 |
内科学 | 6342篇 |
皮肤病学 | 1317篇 |
神经病学 | 2449篇 |
特种医学 | 2246篇 |
外国民族医学 | 1篇 |
外科学 | 4130篇 |
综合类 | 166篇 |
一般理论 | 5篇 |
预防医学 | 1578篇 |
眼科学 | 583篇 |
药学 | 3317篇 |
中国医学 | 444篇 |
肿瘤学 | 2668篇 |
出版年
2024年 | 23篇 |
2023年 | 244篇 |
2022年 | 771篇 |
2021年 | 1236篇 |
2020年 | 559篇 |
2019年 | 798篇 |
2018年 | 974篇 |
2017年 | 798篇 |
2016年 | 1155篇 |
2015年 | 1528篇 |
2014年 | 1802篇 |
2013年 | 2061篇 |
2012年 | 3076篇 |
2011年 | 3017篇 |
2010年 | 1723篇 |
2009年 | 1512篇 |
2008年 | 2093篇 |
2007年 | 1889篇 |
2006年 | 1686篇 |
2005年 | 1559篇 |
2004年 | 1203篇 |
2003年 | 1054篇 |
2002年 | 896篇 |
2001年 | 787篇 |
2000年 | 720篇 |
1999年 | 511篇 |
1998年 | 201篇 |
1997年 | 129篇 |
1996年 | 113篇 |
1995年 | 78篇 |
1994年 | 90篇 |
1993年 | 74篇 |
1992年 | 145篇 |
1991年 | 153篇 |
1990年 | 171篇 |
1989年 | 133篇 |
1988年 | 119篇 |
1987年 | 110篇 |
1986年 | 93篇 |
1985年 | 64篇 |
1984年 | 43篇 |
1983年 | 38篇 |
1982年 | 28篇 |
1981年 | 36篇 |
1979年 | 23篇 |
1978年 | 22篇 |
1977年 | 23篇 |
1975年 | 18篇 |
1974年 | 17篇 |
1970年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
71.
Tracy W. Harachi Yoonsun Choi Robert D. Abbott Richard F. Catalano Siri L. Bliesner 《Prevention science》2006,7(4):359-368
While there is growing awareness for the need to examine the etiology of problem behaviors across cultural, racial, socioeconomic, and gender groups, much research tends to assume that constructs are equivalent and that the measures developed within one group equally assess constructs across groups. The meaning of constructs, however, may differ across groups or, if similar in meaning, measures developed for a given construct in one particular group may not be assessing the same construct or may not be assessing the construct in the same manner in other groups. The aims of this paper were to demonstrate a process of testing several forms of equivalence including conceptual, functional, item, and scalar using different methods. Data were from the Cross-Cultural Families Project, a study examining factors that promote the healthy development and adjustment of children among immigrant Cambodian and Vietnamese families. The process described in this paper can be implemented in other prevention studies interested in diverse groups. Demonstrating equivalence of constructs and measures prior to group comparisons is necessary in order to lend support of our interpretation of issues such as ethnic group differences and similarities. 相似文献
72.
73.
Jun-Seok Lee Byung-Hwan Yang Jang-Han Lee Jun-Ho Choi Ihn-Geun Choi Sae-Byul Kim 《Clinical neurophysiology》2007,118(11):2489-2496
OBJECTIVE: Recent findings have demonstrated that the EEG possesses long-range temporal (auto-) correlations (LRTC) in the dynamics of broad band oscillations. The analysis of LRTC provides a quantitative index of statistical dependencies in oscillations on different time scales. We analyzed LRTC in resting EEG signals in depressed outpatients and healthy controls. METHODS: The participants in this study were 11 non-depressed, age-matched controls, and 11 unmedicated unipolar depressed patients. EEG data were obtained from each participant during 5-min resting baseline periods with eyes closed and then analyzed with detrended fluctuation analysis (DFA), a scaling analysis method that quantifies a simple parameter to represent the correlation properties of a time series. The scaling exponent, the result of DFA, provides a quantitative measure of LRTC from the EEG. RESULTS: The present study demonstrates that all the scaling exponents in depressed patients and healthy controls were greater than 0.5 and less than 1.0, regardless of condition. Furthermore, the scaling exponents of depressed patients have relatively higher values in whole brain regions compared to healthy controls, with significant differences at F3, C3, T3, T4 and O1 channels (p<0.05). Finally, a significant linear correlation was observed between the severity of depression and the scaling exponent over most of the channels, except O2. CONCLUSIONS: These results suggest that the brain affected by a major depressive disorder shows slower decay of the LRTC, and that the persistence of the LRTC of EEG in depressed patients was associated with the severity of depression over most of the cortical areas. SIGNIFICANCE: The DFA method may broaden our understanding of the psychophysiological basis of depression. 相似文献
74.
75.
A. Mori S. Urabe M. Asada Y. Tanaka H. Tazaki I. Yamamoto N. Kimura T. Ozawa S. T. Morris R. Hickson P. R. Kenyon H. Blair C. B. Choi T. Arai 《Transboundary and Emerging Diseases》2007,54(7):342-345
Concentrations of metabolites and immunoreactive insulin (IRI) and activities of enzymes related to energy metabolism were measured in plasma of Korean and Japanese beef cattle, which were raised by the indoor feeding system programmed to feed larger amount of roughage in their growing periods and larger amount of concentrate diet in their finishing periods (Japanese feeding system), and grazing New Zealand beef cattle. By the Japanese beef grading system, Korean and Japanese beef cattle showed high beef quality score, average grade 3.3 and 3.6, respectively. The plasma free fatty acid and lactate concentrations and lactate dehydrogenase (LDH), malate dehydrogenase (MDH) and aspartate aminotransferase (AST) activities in Korean beef cattle were significantly higher than those in Japanese beef cattle. The plasma lactate concentration in Korean beef cattle was 8.40 mmol/l, which was similar to the values observed in lactic acidosis. The higher activities of plasma LDH, MDH and AST may indicate slight liver damage by slightly acidotic conditions in Korean beef cattle. New Zealand beef cattle fed on pasture which they harvest by grazing showed significantly lower plasma glucose, cholesterol, lactate and IRI concentrations and enzyme activities than those in Korean and Japanese beef cattle fed on larger amount of concentrate diets. Plasma metabolite concentrations and energy metabolism‐related enzyme activities may be good indicators for evaluating metabolic conditions of beef cattle raised by different feeding systems. 相似文献
76.
77.
Bum Soon Choi Mi Jung Shin Suk Joon Shin Young Soo Kim Yeong Jin Choi Yong-Soo Kim In Sung Moon Suk Young Kim Yong Bok Koh Byung Kee Bang Chul Woo Yang 《American journal of transplantation》2005,5(6):1354-1360
We report here our 10-year experience of a biopsy performed at day 14 after transplantation in 304 patients with stable graft function. The factors that may have influenced subclinical rejection were analyzed according to histology. The incidence of subclinical rejection was 13.2%. Addition of mycophenolate mofetile (MMF) as a primary immunosuppressant significantly decreased the incidence of subclinical rejection compared with patients without such treatment (odds ratio, 0.23; p < 0.05). On the other hand, HLA-DR antigen mismatch (odds ratio, 2.39) and unrelated donor (odds ratio, 2.10) were also significantly associated with decreased subclinical rejection (p < 0.05). The incidence of acute rejection in patients with normal findings was lower than in those with borderline changes or subclinical rejection (0.23 +/- 0.05 vs. 0.48 +/- 0.07 and 0.60 +/- 0.11, respectively; p < 0.05). The graft survival rates in patients with subclinical rejection were lower than in patients with normal or borderline changes at 1 (88.4% vs. 97.9% and 99.1%; p < 0.05), 5 (77.8% vs. 96.2% and 95.9%; p < 0.05) and 10 (62.3% vs. 96.2% and 93.7%; p < 0.05) years. Thus, a protocol biopsy performed on day 14 after transplantation is useful for predicting graft survival. Triple therapy including MMF, related donor and HLA-DR antigen match are important factors for reducing subclinical rejection in living-donor renal transplantation. 相似文献
78.
The Stiles-Crawford effect of the first kind (SCE-I) was measured on both emmetropic and myopic subjects at six different retinal locations. The results revealed a number of significant discrepancies in receptor alignment between the groups of different refractive errors. In myopic subjects, the receptors in the nasal retina (i.e. between the fovea and the optic nerve head) were found to be aligned nasally towards the optic nerve head, whereas the receptors in the temporal retina were aligned towards the centre of the exit pupil. In emmetropic subjects, the receptors across the retina were finely tuned towards the centre of the exit pupil. The magnitude of the receptor displacement in myopic subjects was found to be directly associated with the length of the eyeball. 相似文献
79.
Guk-Hee Suh Hyun Gyun Son Young-Su Ju Kyeong Hyeong Jcho Byeong Kil Yeon Young Min Shin Baik Seok Kee Sung-Ku Choi 《The American journal of geriatric psychiatry》2004,12(5):509-516
OBJECTIVE: Behavioral disturbances in dementia are extremely prominent and distressful, and often result in serious physical, social, and economic consequences. The authors compared the efficacy and tolerability of risperidone and haloperidol in the treatment of behavioral and psychological symptoms of dementia (BPSD) in institutionalized elderly Korean patients with Alzheimer disease, vascular dementia, or mixed dementia. METHODS: This was an 18-week double-blind, crossover study involving 120 patients who were randomly assigned to receive flexible doses (0.5-1.5 mg/day) of risperidone or haloperidol. BPSD were assessed using the Korean version of the Behavioral Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD-K), the Korean version of the Cohen-Mansfield Agitation Inventory (CMAI-K), and the Clinical Global Impression of Change scale (CGI-C). Safety and tolerability assessments included the Extrapyramidal Symptom Rating Scale and the incidence of adverse events. RESULTS: Both risperidone and haloperidol were efficacious in alleviating BPSD. However, when receiving risperidone, patients showed significantly greater improvement than when receiving haloperidol in the total and subscale scores of the BEHAVE-AD-K, the total and subscale scores of the CMAI-K, and the scores on the CGI-C scale. Also, risperidone had an additional benefit on aggressiveness and anxieties/phobias. The risk of antipsychotic-induced parkinsonism throughout this study was significantly lower with risperidone than with haloperidol. CONCLUSION: Risperidone had a favorable efficacy and tolerability profile compared with haloperidol in the treatment of BPSD in this patient population. 相似文献
80.
BACKGROUND: IgE-mediated carboplatin hypersensitivity reactions occur in up to 30% of patients receiving this agent for chemotherapy of solid tumors, thus limiting therapeutic options. OBJECTIVE: To describe our experience with intravenous carboplatin desensitization regimens, which culminated in a standardized, successful protocol for safe administration. METHODS: Eight consecutive patients with ovarian cancer who had experienced severe anaphylactic reactions to carboplatin were referred to our hospital. Intradermal skin testing was performed by raising a 3-mm bleb by injection of undiluted carboplatin at 10 mg/mL, and the wheal size was read at 20 minutes. The outcomes of the various desensitization regimens were documented prospectively, and the experience gained was used to develop a standardized protocol for administration. RESULTS: All patients had positive intradermal skin test results. The first 3 patients were treated with short (90 minutes to 6 hours) desensitization protocols, and all protocols failed on the first or second infusions. These 3 and a subsequent 5 patients were given intravenous carboplatin according to a protocol of gradual dose escalation over a 4-log dose range given during a 4-day period, with subsequent 3-weekly infusions given more rapidly by omitting the most dilute log dose on each occasion. All patients tolerated the longer infusion protocol without event, and all but 1 patient experienced appropriate tumor marker response. CONCLUSIONS: Short carboplatin desensitization protocols (less than 6 hours) have an unacceptable failure rate in patients with carboplatin allergy, but longer infusion times (days) are well tolerated without recurrence of the allergic reaction and with good tumor response. In cases where carboplatin is the optimal therapeutic agent, clinicians should not be deterred by an anaphylactic reaction to it or by failure of shorter desensitization regimens. 相似文献