首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   13172篇
  免费   946篇
  国内免费   118篇
耳鼻咽喉   94篇
儿科学   442篇
妇产科学   404篇
基础医学   1780篇
口腔科学   271篇
临床医学   1136篇
内科学   2540篇
皮肤病学   211篇
神经病学   920篇
特种医学   460篇
外科学   2278篇
综合类   615篇
一般理论   4篇
预防医学   726篇
眼科学   347篇
药学   740篇
  1篇
中国医学   78篇
肿瘤学   1189篇
  2023年   134篇
  2022年   183篇
  2021年   340篇
  2020年   235篇
  2019年   306篇
  2018年   335篇
  2017年   263篇
  2016年   289篇
  2015年   348篇
  2014年   442篇
  2013年   541篇
  2012年   859篇
  2011年   915篇
  2010年   547篇
  2009年   472篇
  2008年   721篇
  2007年   685篇
  2006年   710篇
  2005年   701篇
  2004年   670篇
  2003年   593篇
  2002年   552篇
  2001年   518篇
  2000年   411篇
  1999年   351篇
  1998年   114篇
  1997年   111篇
  1996年   92篇
  1995年   85篇
  1994年   65篇
  1993年   53篇
  1992年   162篇
  1991年   149篇
  1990年   161篇
  1989年   158篇
  1988年   132篇
  1987年   139篇
  1986年   108篇
  1985年   86篇
  1984年   53篇
  1983年   44篇
  1981年   34篇
  1980年   29篇
  1979年   52篇
  1978年   37篇
  1977年   32篇
  1976年   26篇
  1975年   25篇
  1974年   21篇
  1973年   26篇
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
91.
In this paper, the skin blood flow for the stomach and forehead regions of 36 female patients with menstrual symptoms was studied using a moorLDI laser Doppler imager in which the results of 6 typical patients are included. The patterns obtained at the two sites are common to all women in the sample who have menstrual symptoms. Cold stress testing was also investigated to see if it was effective in bringing out any skin blood flow fluctuation at these regions caused by menstrual symptoms. Each patient attended two scanning sessions: one before and the other during menstruation. During each session, the patient was scanned three consecutive times, each on the stomach and the forehead skin regions. For each region, the first measurement was a bare scanning whereas for the second and the third, 85% denatured ethanol (cold stress test) was applied onto the required scan areas. It was found that cold stress testing was able to bring out distinct differences in LDI perfusion images before and during menstruation. Results were best captured when perfusion images were taken approximately after 85% denatured ethanol had been applied in two layers for 30 s, allowed to evaporate over the next 5 min (approximately the time taken to obtain one image), reapplied for another 30 s and then finally over the next 30 s allowed to evaporate further. However, it was impossible to deduce conclusively any correlation regarding migraine and skin blood flow since all the patients for this work had menstrual cramps only.  相似文献   
92.
Various natural and synthetic polymeric materials have been used as scaffold matrices for tissue-engineered skin. However, the commercially available skin replacement products pose problems of poor mechanical properties and immunological rejection. We have thus developed a film of 5 microm thickness, via biaxial stretching of poly(epsilon-caprolactone) (PCL), as a potential matrix for living skin replacements. The aim of this study was to evaluate the feasibility of using biaxially stretched PCL films as matrices for culturing human dermal fibroblasts. For this purpose, we cultured human dermal fibroblasts for 7 days on the films. Glass cover slips and polyurethane (PU) sheets were used as controls. The data from phase contrast light, confocal laser, and scanning electron microscopy suggested that biaxially stretched PCL films support the attachment and proliferation of human dermal fibroblasts. Thymidine-labeling results showed quantitatively that cell proliferation on the PCL films was superior to that on the PU samples. These results indicated that biaxially stretched PCL films supported the growth of human dermal fibroblasts and might have potential to be applied in tissue engineering a dermal equivalent or skin graft.  相似文献   
93.
A wide range of drug demand reduction programmes are being carried out in Hong Kong. These include community involvement projects; preventive drug education and publicity through the use of mass media in the form of television and radio announcements and posters; and the production of educational and publicity materials. Most of these programmes are intended to reach young people. The local district campaigns are held every year to arouse awareness of the dangers of drug abuse and to encourage public support in combating such abuse. A selected volunteer group encourages young people to participate in the planning, organization and implementation of drug-abuse prevention projects. A programme called "Youth against drugs scheme", which was launched in 1981, is open to all youth groups, providing an opportunity for young people to plan and implement anti-narcotics publicity projects in their own way with limited supervision. These programmes have proved successful in involving the young in the fight against drug abuse and associated problems.  相似文献   
94.
We have sequenced the mutant beta-actin gene of a tumorigenic human fibroblast cell line (HuT-14T) and found that it carries three mutations that alter the amino acids at positions 36, 83, and 244 as well as a 22-base-pair "insertion" sequence, in the 5' intron, not present in a wild-type gene. The less tumorigenic cell line HuT-14, a progenitor of HuT-14T, has the same codon-244 mutation and the insertion sequence but not the other two mutations. A nontumorigenic cell line that is related to HuT-14 but that has no beta-actin mutations does carry the intron-length polymorphism. We conclude that the mutation at codon 244 occurred first in a beta-actin allele already bearing the 22-base-pair intron insert and that mutations at codons 36 and 83 arose subsequently during the selection for the HuT-14T phenotype. Rat-2 cells synthesize the appropriate charge-variant species of mutant actin protein when transfected with either the singly or the triply mutated beta-actin gene.  相似文献   
95.
Disease-bearing insects brought in by international aircraft into Singapore   总被引:1,自引:0,他引:1  
Fifty-seven (17.3%) of 330 incoming aircraft landing at Changi International Airport were found to harbour mosquitoes and other insects on board. The frequency of insects detected in aircraft from the Southeast Asian countries varied from 7.1% to 32.2%. Live insects were found in 5 (6.1%) of 82 aircraft disinsectized by the "block away" method. The species of mosquitoes brought in were: Culex quinquefasciatus (96), Culex tritaeniorhynchus (1), Aedes albopictus (2) and Aedes aegypti (1). None of the 51 female Culex quinquefasciatus dissected was found to be infected with microfilariae. They key to the prevention of introduction of exotic vectors and transmission of vector- borne diseases is to continue with the existing system of vector surveillance and control at the international airport, rather than routine disinsecting of aircraft landing in Singapore.  相似文献   
96.
Advances in Health Sciences Education - Critical reflection supports enactment of the social roles of care, like collaboration and advocacy. We require evidence that links critical teaching...  相似文献   
97.
Initial cases of coronavirus disease in Hong Kong were imported from mainland China. A dramatic increase in case numbers was seen in February 2020. Most case-patients had no recent travel history, suggesting the presence of transmission chains in the local community. We collected demographic, clinical, and epidemiologic data from 50 patients, who accounted for 53.8% of total reported case-patients as of February 28, 2020. We performed whole-genome sequencing to determine phylogenetic relationship and transmission dynamics of severe acute respiratory syndrome coronavirus 2 infections. By using phylogenetic analysis, we attributed the community outbreak to 2 lineages; 1 harbored a common mutation, Orf3a-G251V, and accounted for 88.0% of the cases in our study. The estimated time to the most recent common ancestor of local coronavirus disease outbreak was December 24, 2019, with an evolutionary rate of 3.04 × 10−3 substitutions/site/year. The reproduction number was 1.84, indicating ongoing community spread.  相似文献   
98.
99.
100.
BackgroundThe aim of this study is to compare the long-term functional outcome and quality of life between total knee arthroplasty (TKA) and fixed-bearing unicompartmental knee arthroplasty (UKA) for the treatment of isolated medial compartment osteoarthritis.MethodsBetween 2000 and 2008, a total of 218 patients underwent primary UKA at our tertiary hospital. A TKA group was matched through 1:1 propensity score matching and adjusted for age, gender, body mass index, preoperative knee flexion, and function scores. All patients had medial compartment osteoarthritis. The patients were assessed with the range of motion, Knee Society Knee Score and Knee Society Function Score, Oxford Knee Score, Short Form-36 physical component score (PCS) and mental component score preoperatively, at 6 months, 2 years, and 10 years. Patients’ satisfaction, expectation fulfillment, and minimal clinically important difference were analyzed.ResultsThere were no differences in baseline characteristics between groups after propensity score matching (P > .05). UKA had greater knee flexion at all time points. Although the Knee Society Function Score was superior in UKA by 5.5, 3, and 4.3 points at 6 months, 2 years, and 10 years, respectively (P < .001), these differences did not exceed the minimal clinically important difference (Knee Society Knee Score 6.1). There were no significant differences in the Oxford Knee Score and Short Form-36 physical component score/mental component score. At 10 years, similar proportions of UKA and TKA were satisfied (90.8% vs 89.9%, P = .44) and had expectation fulfillment (89.4% vs 88.5%, P = .46). Between 2 and 10 years, all function scores deteriorated significantly for both groups (P < .01).ConclusionUKA and TKA are excellent treatment modalities for isolated medial compartment osteoarthritis, with similar functional outcomes, quality of life, and satisfaction at 10 years.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号