全文获取类型
收费全文 | 1441篇 |
免费 | 90篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 47篇 |
妇产科学 | 19篇 |
基础医学 | 213篇 |
口腔科学 | 8篇 |
临床医学 | 131篇 |
内科学 | 346篇 |
皮肤病学 | 13篇 |
神经病学 | 103篇 |
特种医学 | 20篇 |
外科学 | 178篇 |
综合类 | 23篇 |
一般理论 | 2篇 |
预防医学 | 113篇 |
眼科学 | 57篇 |
药学 | 83篇 |
中国医学 | 22篇 |
肿瘤学 | 161篇 |
出版年
2023年 | 17篇 |
2022年 | 18篇 |
2021年 | 42篇 |
2020年 | 22篇 |
2019年 | 32篇 |
2018年 | 54篇 |
2017年 | 23篇 |
2016年 | 24篇 |
2015年 | 40篇 |
2014年 | 32篇 |
2013年 | 75篇 |
2012年 | 96篇 |
2011年 | 80篇 |
2010年 | 56篇 |
2009年 | 45篇 |
2008年 | 79篇 |
2007年 | 96篇 |
2006年 | 84篇 |
2005年 | 73篇 |
2004年 | 71篇 |
2003年 | 52篇 |
2002年 | 34篇 |
2001年 | 51篇 |
2000年 | 50篇 |
1999年 | 39篇 |
1998年 | 11篇 |
1997年 | 9篇 |
1996年 | 17篇 |
1995年 | 11篇 |
1994年 | 13篇 |
1993年 | 11篇 |
1992年 | 16篇 |
1991年 | 27篇 |
1990年 | 13篇 |
1989年 | 23篇 |
1988年 | 18篇 |
1987年 | 12篇 |
1986年 | 10篇 |
1985年 | 14篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 10篇 |
1980年 | 7篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1968年 | 1篇 |
1967年 | 2篇 |
排序方式: 共有1542条查询结果,搜索用时 15 毫秒
21.
Niven Ralph W. Whitcomb K. Lane Shaner Linda Ip Anna Y. Kinstler Olaf B. 《Pharmaceutical research》1995,12(9):1343-1349
Purpose. The objective of this study was to highlight differences in the pulmonary absorption of a monoPEGylated rhG-CSF and rhG-CSF after intratracheal instillation and aerosol delivery.
Methods. Male Sprague Dawley rats (250 g) were anesthetized and intratracheally instilled (IT) with protein solution or were endotracheally intubated and administered aerosol for 20 min via a Harvard small animal ventilator. A DeVilbiss Aerosonic nebulizer containing 5 ml of protein solution at 3 mg/ml was used to generate aerosol. The volume of protein solution deposited in the lung lobes was estimated to be 13 µl after delivery of Tc-99m HSA solutions. The PEGylated proteins consisted of a 6 kDa (P6) or 12 kDa PEG (PI2) linked to the N-terminus of rhG-CSF. rhG-CSF also was administered IT in buffers at pH 4 and pH 7 and in dosing volumes ranging from 100 to 400 µl. Blood samples were removed at intervals after dosing and the total white blood cell counts (WBC) were determined. Plasma was assayed for proteins by an enzyme immuno assay.
Results. The plasma protein concentration v. time profiles were strikingly different for aerosol v. IT delivery. The C
max values for rhG-CSF and P12 after aerosol delivery were greater than found after IT (Aerosol: 598 ± 135 (ng/ml) rhG-CSF; 182 ± 14 P12 v. IT: 105 ± 12 rhG-CSF; 65.9 ± 5 P12). Similarly, Tmax was reached much earlier after aerosol administration (Aerosol: 21.7 ± 4.8 (min) rhG-CSF; 168 ± 31 P12 v. IT: 100 ± 17 rhG-CSF; 310 ± 121 P12). Estimated bioavailabilities (Flung %) were significantly greater via aerosol delivery than those obtained after IT (Aerosol: 66 ± 14 rhG-CSF; 12.3 ± 1.9 P12 v. IT: 11.9 ± 1.5 rhG-CSF; 1.6 ± 0.1 P12). An increase in circulating WBC counts was induced by all proteins delivered to the lungs. The rate and extent of absorption of rhG-CSF was not influenced by the pH employed nor the instilled volume.
Conclusions. Estimates of bioavailability are dependent upon the technique employed to administer drug to the lungs. Aerosol administration provides a better estimate of the systemic absorption of macromolecules. 相似文献
22.
The effect of dietary fat on mammary tumor incidence, estrogen-binding capacity as related to the hormone dependency of the tumors, and circulating estrogen levels in Sprague-Dawley rats given an oral dose of 7,12-dimethylbenz[a]anthracene (DMBA) was investigated. Rats were fed diets consisting of 0.5, 5, or 20% corn oil starting at weaning and were administered 5 mg DMBA at 50 days of age. Tumor incidences were 13, 46, and 75% for the groups given 0.5, 5, and 20% fat, respectively, when the experiment was terminated 20-22 weeks later. Serum estradiol, measured at proestrus at 50 days of age and at the end of the experiment, was slightly depressed at both time points in rats fed the 0.5% fat diet but was similar in the other 2 groups. Serum estrone levels were not significantly different at either time point. Estrogen receptor levels in the tumor were the same in the groups given 5 and 20% fat but were lower in the group given 0.5% fat. No difference was detected in the progesterone receptor concentrations. Furthermore, most (approximately 70%) of the tumors in all 3 dietary groups regressed in response to ovariectomy, which suggested that dietary fat has very little influence on the estrogen dependence of the tumor. This observation suggested that fat intake does not result in any intrinsic difference in the biochemical action of estrogen. 相似文献
23.
Margaret Ip D J Lyon F Chio A F Cheng 《Infection control and hospital epidemiology》2004,25(2):126-129
OBJECTIVES: To review the incidence and trends of MRSA during a 12-year (1989-2000) period at a university teaching hospital and the relationship between strain distribution by antibiogram and molecular typing. DESIGN: Retrospective review of laboratory-based surveillance records on MRSA isolation and characterization of strains by antimicrobial susceptibility and PFGE. A patient episode was counted at the time when MRSA was first isolated. SETTING: A 1,350-bed university teaching hospital in Hong Kong. PATIENTS: Those with clinical isolates of MRSA. RESULTS: During 1989 to 2000, the hospital recorded 1,203,175 deaths and discharges (D&D) and encountered 5,707 patient episodes of new MRSA isolation. The overall incidence of patient episodes of MRSA was 0.47/100 D&D. In 1989, the incidence was 0.81/100 D&D and fell to a low of 0.33/100 D&D in 1995, but then rose to 0.50/100 D&D in 2000. Antibiogram and DNA typing identified 5 major types. PFGE type A constituted 68% (211/312) of isolates and was present throughout the 12-year period. PFGE type B constituted 13% (40/312) of isolates and was only present from 1995 to 2000. These isolates form a distinct clone and had unique antibiotic resistance profiles. CONCLUSIONS: The study showed the establishment of a dominant MRSA clone (PFGE type A group) in the intensive care, medical, and surgical units and the appearance of a new MRSA strain in 1995 (PFGE type B), which partly explained the rise in incidence of MRSA cases and a disproportionate rise in MRSA bacteremia from 1995 to 2000. 相似文献
24.
Kiki S. N. Liu Julie Y. Chen Kai-Sing Sun Joyce P. Y. Tsang Patrick Ip Cindy L. K. Lam 《Nutrients》2022,14(14)
To tackle unhealthy eating among adolescents, it is crucial to understand the dietary knowledge, attitudes, and practices (KAP) on which adolescent eating habits are based. This qualitative study identifies the gaps in KAP by exploring what Chinese adolescents know, perceive, and practice regarding healthy eating to better inform targeted interventions for this important health problem. Parent–adolescent dyads were purposively sampled based on, for example, the dietary intake, age, and gender of the adolescent and household income, and each completed a 30 to 60 min interview. Twelve themes were synthesized: knowledge: (1) dietary recommendations, (2) health outcomes of healthy eating, (3) nutrition content in food, and (4) access to healthy meals; attitudes: (5) outcome expectation for healthy eating, (6) food preferences, and (7) self-efficacy regarding adopting healthy eating; and practices: (8) going grocery shopping for healthy food, (9) eating home-prepared meals. (10) eating out in restaurants or consuming takeaway food, (11) fruit and vegetable consumption, and (12) snacking, perceived unhealthy eating to be low risk, made unhealthy choices regarding snacking and eating out, and had insufficient fruit and vegetable intake. Programs should emphasize the positive short-term health outcomes of healthy eating and empower adolescents to acquire food preparation skills to sustain healthy eating habits. 相似文献
25.
Vivian H. Y. Ip MBChB Mark C. Rockley BScH Ban C. H. Tsui MD 《Journal canadien d'anesthésie》2013,60(12):1272-1273
26.
27.
Kajua B. Lor Sakura Moua Eric J. Ip 《Journal of immigrant and minority health / Center for Minority Public Health》2016,18(2):397-401
To determine the frequency and perceptions of herbal medicine use among Hmong Americans. Cross-sectional telephone survey. Sacramento, California Hmong community. Out of 118 subjects reached, 77 (65.3 %) reported lifetime use of herbal medicines. A majority of respondents agreed that herbal medicines were able to treat the body as a whole. Respondents felt that a leaflet of information indicating uses/side effects would be important to include for herbal medicines. Herbal medicine use was commonly reported among Hmong Americans. Thus, health care providers should be encouraged to discuss these alternative medicines with their Hmong American patients. 相似文献
28.
Anabolic-androgenic steroids (AAS) and other performance-enhancing drugs (PEDs) are commonly misused to increase muscle size and strength, as well as improve physical appearance. Many AAS and certain PEDs are administered via injection and therefore pose a risk for transmission of infectious diseases such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), and skin and soft tissue infections (SSTIs). Further, AAS users may be more likely to take part in high-risk sexual behaviors than non-AAS users. This review explores the prevalence of infectious diseases as well as risky injection practices and sexual behaviors of AAS users in the current literature. A comprehensive MEDLINE search (1984–17 April 2015) for English language reports was performed on AAS users. Ten studies analyzed the prevalence of HIV infection, 6 studies analyzed HBV infection, and 6 studies analyzed HCV infection; 20 studies analyzed injection practices and 7 studies analyzed high-risk sexual behaviors of AAS users. HIV, HBV, HCV, and SSTIs have been associated with AAS users. In particular, HIV infection seems much higher among homosexual male AAS users. AAS users also take part in high-risk injection practices but to a much lower extent than intravenous drug users. AAS users are also more likely to engage in high-risk sexual behaviors than the general population. Clinicians and health-policy leaders may utilize these findings to implement strategies to decrease the spread of infectious diseases. 相似文献
29.
Jun Feng Author Vitae Horace H.S. Ip Author Vitae 《Computers in biology and medicine》2009,39(6):489-500
Although many deformable models have been proposed in medical applications for segmenting isolated structures in the human anatomy, not much of such work had been done on tubular structures such as the vasculature. In this paper, we propose a statistical assembled model for tubular structures (SAMTUS) to segment entire tubular structure from three-dimensional (3D) volumetric data. To our knowledge, there is no literature about the statistical deformable model for entire tubular structures. Specifically, the statistical tubular model is composed of a statistical axis model (SAM) and a statistical surface model (SSM). Both of them are assembled from a set of branch segments through the control points. Instead of searching for fuzzy correspondence along tubular axes or surfaces, we build point matching between feature points along tubular segments, and train SAM and SSM independently to characterize, respectively, the axial and the cross-sectional variation of the entire structure. In this way, more accurate point correspondence can be established, and a larger number of deformation modes can be captured. Our SAMTUS-based segmentation process consists of three stages: initialization, model fitting and final refinement. The experimental results demonstrate that the algorithm obtains good quantifications on the morphology and volume of the vasculature of the zebrafish which is being used increasingly as a specimen for drug screening and genomic research. 相似文献
30.
Computed tomographic evaluation of the role of craniofacial and upper airway morphology in obstructive sleep apnea in Chinese 总被引:5,自引:0,他引:5
OBJECTIVES: To evaluate the relationship between cephalometric parameters, upper airway morphological factors and obstructive sleep apnea (OSA) in Chinese subjects. DESIGN: Polysomnogram (PSG) were performed and scored using standard criteria. Supine lateral cephalometric parameters and pharyngeal cross-sectional areas at the level of velopharynx (VA) and hypopharynx (HA) were measured from computed tomographic scans. The roles of these parameters and other anthropometric/demographic characteristics in OSA (apnea hypopnea index, AHI > or = 5) and their relationship with severity of OSA were explored by multiple logistic and multinominal regression analysis. RESULTS: Ninety-two subjects, ranging from normal (n = 36), mild/moderate OSA (n = 34) to severe OSA (n = 22), were evaluated. Compared with normal subjects, OSA subjects were heavier (body mass index 27 vs. 24 kg/m2) and older (47 vs. 42 years of age); had smaller VA size and VA to HA ratio, lower positioned hyoid bone, longer and thicker soft palate, and more retropositioned mandible relative to maxilla. After controlling for body mass index and age, subjects with severe OSA (AHI > 30) had more retropositioned mandible relative to maxilla (odds ratio, OR 1.31, P = 0.044) and longer soft palate (OR 1.16, P = 0.01), while those with mild/moderate OSA had larger VA to HA ratio (OR 0.17, P = 0.018). CONCLUSIONS: Craniofacial factors and upper airway morphology contributed to severity of OSA in Chinese subjects. Having controlled for obesity, more retropositioned mandible was associated with more severe OSA. 相似文献