全文获取类型
收费全文 | 13950篇 |
免费 | 745篇 |
国内免费 | 64篇 |
专业分类
耳鼻咽喉 | 166篇 |
儿科学 | 238篇 |
妇产科学 | 219篇 |
基础医学 | 1926篇 |
口腔科学 | 1405篇 |
临床医学 | 1109篇 |
内科学 | 2960篇 |
皮肤病学 | 284篇 |
神经病学 | 1295篇 |
特种医学 | 343篇 |
外科学 | 1856篇 |
综合类 | 44篇 |
一般理论 | 2篇 |
预防医学 | 1101篇 |
眼科学 | 257篇 |
药学 | 946篇 |
中国医学 | 127篇 |
肿瘤学 | 481篇 |
出版年
2024年 | 11篇 |
2023年 | 111篇 |
2022年 | 110篇 |
2021年 | 481篇 |
2020年 | 295篇 |
2019年 | 385篇 |
2018年 | 493篇 |
2017年 | 314篇 |
2016年 | 400篇 |
2015年 | 483篇 |
2014年 | 660篇 |
2013年 | 735篇 |
2012年 | 1196篇 |
2011年 | 1307篇 |
2010年 | 733篇 |
2009年 | 554篇 |
2008年 | 950篇 |
2007年 | 953篇 |
2006年 | 899篇 |
2005年 | 727篇 |
2004年 | 655篇 |
2003年 | 534篇 |
2002年 | 443篇 |
2001年 | 164篇 |
2000年 | 148篇 |
1999年 | 137篇 |
1998年 | 68篇 |
1997年 | 56篇 |
1996年 | 39篇 |
1995年 | 44篇 |
1994年 | 27篇 |
1993年 | 32篇 |
1992年 | 67篇 |
1991年 | 65篇 |
1990年 | 44篇 |
1989年 | 63篇 |
1988年 | 40篇 |
1987年 | 36篇 |
1986年 | 30篇 |
1985年 | 29篇 |
1984年 | 23篇 |
1983年 | 18篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1975年 | 16篇 |
1974年 | 11篇 |
1973年 | 15篇 |
1971年 | 11篇 |
1969年 | 13篇 |
1968年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
61.
Daniel A Waschbusch Normand J Carrey Michael T Willoughby Sara King Brendan F Andrade 《Journal of clinical child and adolescent psychology》2007,36(4):629-644
This study examined whether response to behavior modification with and without methylphenidate differed for children with attention-deficit/hyperactivity disorder (ADHD) and conduct problems (CP) depending on the presence of callous/unemotional (CU) traits. Participants were 37 children ages 7 to 12, including 19 with ADHD/CP-only and 18 with ADHD/CP-CU, referred to a university-based summer treatment program. Results showed that ADHD/CP-CU children had worse behavior in the behavior-therapy-only (BT-only) condition, especially on measures of CP, noncompliance, and rule violations, but these differences largely disappeared when medication was added to BT. Children with ADHD/CP-CU were also less likely to be normalized by treatment than were children with ADHD/CP-only. These findings, though tentative, suggest that children with ADHD/CP-CU may not show a sufficient positive response to BT alone and that the combination of medication and BT may be especially important for them. 相似文献
62.
Effect of voice rehabilitation on oral communication of Parkinson's disease patients 总被引:3,自引:0,他引:3
E. C. de Angelis L. F. Mourao H. B. Ferraz M. S. Behlau P. A. L. Pontes L. A. F. Andrade 《Acta neurologica Scandinavica》1997,96(4):199-205
Voice and speech disorders are common in Parkinson's disease patients and may lead to social isolation. We employed routine clinical voice therapy measures to evaluate the effect of voice rehabilitation. Twenty patients with a stable drug regimen participated in this study. The patients were assessed before and after a program of voice rehabilitation consisting of 13 group therapy sessions during 1 month, with emphasis on the increase in laryngeal sphincteric activity. Voice rehabilitation produced an increase in maximal phonation times, decrease in the values of s/z ratio and air flow, increase in vocal intensity, decrease in the complaints of weak and strained-strangled voice and monotonous and unintelligible speech and elimination of complaints of swallowing alterations. These data indicate a greater glottic efficiency after voice rehabilitation reflecting a more functional oral communication. 相似文献
63.
Brett Claire M. Washington Carla B. Ott Ronda J. Gutierrez Marcelo M. Giacomini Kathleen M. 《Pharmaceutical research》1993,10(3):423-426
The therapeutic efficacy of nucleosides and nucleoside analogues as antitumor, antiviral, antiparasitic, and antiarrhythmic agents has been well documented. Pharmacokinetic studies suggest that many of these compounds are actively transported in the kidney. The goal of this study was to determine if therapeutically relevant nucleosides or analogues interact with the recently characterized Na+-driven nucleoside transport system of the brush border membrane of the human kidney. Brush border membrane vesicles (BBMV) were prepared from human kidney by divalent cation precipitation and differential centrifugation. The initial Na+-driven 3H-uridine uptake into vesicles was determined by rapid filtration. The effect of several naturally occurring nucleosides (cytidine, thymidine, adenosine), a pyrimidine base (uracil), a nucleotide (UMP), and several synthetic nucleoside analogues [zidovudine (AZT), cytarabine (Ara-C), and dideoxycytidine (ddC)] on Na+–uridine transport was determined. At a concentration of 100 µM the naturally occurring nucleosides, uracil, and UMP significantly inhibited Na+-uridine transport, whereas the three synthetic nucleoside analogues did not. Adenosine competitively inhibited Na+-uridine uptake with a K
i of 26.4 µM (determined by constructing a Dixon plot). These data suggest that naturally occurring nucleosides are substrates of the Na+–nucleoside transport system in the renal brush border membrane, whereas synthetic nucleoside analogues with modifications on the ribose ring are not. The K
i of adenosine is higher than clinically observed concentrations and suggests that the system may play a physiologic role in the disposition of this nucleoside. 相似文献
64.
Andrade C Gangadhar BN Subbakrishna DK Channabasavanna SM Pradhan N 《Convulsive therapy》1988,4(4):297-305
In a double-blind prospective study, 29 endogenously depressed patients (RDC) were randomized into sinusoidal wave (SW) and brief-pulse (BP) electroconvulsive therapy (ECT) groups. Bilateral modified treatments were administered on alternate days, three per week, and the treatment variables of current dosage and seizure duration were monitored for each treatment. Significantly more patients responded to SW than to BP ECT, but a comparable number of treatments was required to produce this response in the two groups. There was no difference in clinical or treatment variables between the SW and the BP groups, nor between ECT responders and nonresponders, with the exception that the SW-treated patients received larger doses of current per treatment than did the BP patients. For endogenous depression treated with ECT, we conclude that cumulative seizure duration may not be a parameter of significance, that overall rate of recovery in ECT responders is independent of stimulus waveform, and that some depressives may respond to SW but not to BP ECT. We suggest that the antidepressant effect of the ECT seizure may be characterized by a therapeutic window in current requirements; alternatively, a putative response threshold (again in terms of current requirement) may exist, which is higher in some patients than in others. 相似文献
65.
Thirty-two endogenous depressed patients (RDC) were treated with electroconvulsive therapy. Four patients (12.5%) developed a transient manic reaction; in two cases, this reaction occurred in mid-depression. Mania is not a generally recognized side effect of ECT; we detail the clinical characteristics, but fail to define clinical predictors of vulnerability. 相似文献
66.
An ideal vaccine has certain biological and physical characteristics. Technological advances have provided new strategies that may help the design of such a vaccine. 相似文献
67.
Stevenson HL Labruna MB Montenieri JA Kosoy MY Gage KL Walker DH 《Journal of medical entomology》2005,42(2):163-167
The flea and rodent samples studied in this project were collected from field study sites in New Mexico from winter 1998 to spring 2001. During this period, 155 small rodents (14 different species) were live-trapped and combed for the presence of fleas. A total of 253 fleas were collected, comprising 21 species. Two of the 253 fleas collected were polymerase chain reaction (PCR) positive for the Rickettsia 17-kDa protein gene. These two fleas were both Anomiopsyllus nudata Baker, each collected from an individual Neotoma albigula Hartley, on two occasions. Individual fleas positive for the Rickettsia 17-kDa protein gene were then tested with primers targeting the rickettsial genes for citrate synthase (gltA) and two major outer membrane proteins (ompA and ompB). The nucleotide sequences of the PCR products of these two fleas were identical to each other and were 100% (394/394), 100% (1150/1150), 99.8% (469/470), and 99.3% (818/824) similar to the corresponding sequences of the 17-kDa, gltA, ompA, and ompB genes of Rickettsia felis, respectively. Flea homogenates of individual PCR-positive fleas were inoculated into shell vials seeded with Vero cells, and the Gimenez stain technique was used to demonstrate the presence of Rickettsia-like organisms in detached cells found in aspirated medium 19 d after inoculation. These cells were harvested and tested by PCR, targeting portions of the 17-kDa and gltA genes, resulting in products 100% identical to R. felis. This work comprises the first report of R. felis detection in a flea species (A. nudata) endemic to the New World. 相似文献
68.
de Andrade AL Pimenta FC Laval CA de Andrade JG Guerra ML Brandileone MC 《Journal of clinical microbiology》2004,42(5):2345-2346
We present a case of invasive pneumococcal infection in a healthy 10-month-old infant from whom Streptococcus pneumoniae serotype 23F was isolated from the blood and serotype 23B was isolated from the cerebrospinal fluid. Both serotypes were penicillin nonsusceptible. Pulsed-field gel electrophoresis analysis demonstrated that the two serotypes had distinct DNA patterns, indicating that infection did not occur as a result of capsular transformation but as a result of a mixed infection with two distinct pneumococcal serotypes. 相似文献
69.
70.
Maternal origin of transferrin receptor positive cells in venous blood of pregnant women 总被引:1,自引:0,他引:1
Anna Slunga-Tallberg Wa'el El-Rifai Mauri Keinänen Kari Ylinen Tapio Kurki Katherine Klinger Olavi Ylikorkala Marcelo L. Larramendy Sakari Knuutila 《Clinical genetics》1996,49(4):196-199
We studied the origin of transferrin receptor (CD71) positive cells in blood from seven women pregnant with a male fetus in order to explore if fetal cells could be detected among them. We used a technique that allows direct chromosomal analysis by in situ hybridization on immunologically and morphologically classified cells. Enrichment was performed by magnetic activated cell sorting (miniMACS)® using an anti-CD71 monoclonal antibody. The cells were immunophenotyped by alkaline phosphatase anti-alkaline phosphatase immunostaining with the same antibody. The origin of the immunophenotyped cells was studied by in situ hybridization using an X cosmid Y repeat chromosome specific probe cocktail. CD71 positive cells were found in six of the seven women at the range of 4 to 43 in respective samples. Over 90% of the CD71 positive cells were nucleated erythrocytes. None of the detected positive cells were shown to be fetal. Thus, the use of transferrin receptor antigen alone in combination with the miniMACS® may not be sufficient for enrichment of fetal cells. 相似文献