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   31707篇
  免费   2006篇
  国内免费   81篇
耳鼻咽喉   271篇
儿科学   729篇
妇产科学   592篇
基础医学   4492篇
口腔科学   695篇
临床医学   2921篇
内科学   6086篇
皮肤病学   526篇
神经病学   3518篇
特种医学   1353篇
外国民族医学   55篇
外科学   4412篇
综合类   382篇
一般理论   10篇
预防医学   2496篇
眼科学   889篇
药学   2125篇
中国医学   33篇
肿瘤学   2209篇
  2022年   172篇
  2021年   463篇
  2020年   298篇
  2019年   460篇
  2018年   531篇
  2017年   439篇
  2016年   500篇
  2015年   659篇
  2014年   855篇
  2013年   1223篇
  2012年   1857篇
  2011年   1933篇
  2010年   1073篇
  2009年   992篇
  2008年   1750篇
  2007年   1881篇
  2006年   1794篇
  2005年   1820篇
  2004年   1779篇
  2003年   1651篇
  2002年   1589篇
  2001年   451篇
  2000年   401篇
  1999年   425篇
  1998年   374篇
  1997年   333篇
  1996年   284篇
  1995年   263篇
  1994年   235篇
  1993年   230篇
  1992年   272篇
  1991年   240篇
  1990年   214篇
  1989年   241篇
  1988年   221篇
  1987年   224篇
  1986年   204篇
  1985年   193篇
  1984年   245篇
  1983年   205篇
  1982年   246篇
  1981年   221篇
  1980年   203篇
  1979年   187篇
  1978年   161篇
  1977年   115篇
  1976年   147篇
  1975年   136篇
  1974年   163篇
  1973年   120篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
81.
SUMMARY: This report concerning the immunization of adolescents (ie, persons 11–21 years of age, as defined by the American Medical Association [AMA] and the American Academy of Pediatrics [AAP]) is a supplement to previous publications (ie, MMWR 1994;43[No. RR-1] 1–38; the AAP 1994 Red Book: Report of the Committee on Infectious Diseases; Summary of Policy Recommendations for Periodic Health Examination, August 1996 from the American Academy of Family Physicians [AAFP]; and AMA Guidelines for Adolescent Preventive Services [GAPS]: Recommendations and Rationale). This report presents a new strategy to improve the delivery of vaccination services to adolescents and to integrate recommendations for vaccination with other preventive services provided to adolescents. This new strategy emphasizes vaccination of adolescents 11–12 years of age by establishing a routine visit to their health-care providers. Specifically, the purposes of this visit are to a) vaccinate adolescents who have not been previously vaccinated with varicella virus vaccine, hepatitis B vaccine, or the second dose of the measles, mumps, and rubella (MMR) vaccine; b) provide a booster dose of tetanus and diphtheria toxoids; c) administer other vaccines that may be recommended for certain adolescents; and d) provide other recommended preventive services. The recommendations for vaccination of adolescents are based on new or current information for each vaccine. The most recent recommendations from AC1P, AAP, AAFP, and AMA concerning specific vaccines and delivery of preventive services should be consulted for details.  相似文献   
82.
83.
The forces to produce fractures of the os calcis are combined compression and shear under a cranio-caudal impulse of 10-40 kN and a short time of stroke about 10-40 ms. The main patterns in biomechanics of calcaneal fractures are the time of stroke and the geometrical position of the foot in the moment of impact. Furthermore individual structural changes of the calcaneal cancellous bone, age, diseases as Diabetes mellitus and vascular obliterations are to be respected. Operative treatment of these fractures needs an understanding of the pathomechanism of the intracalcaneal shear-tension-forces. With plantarflexion of the foot combined with vertical forces within 40 ms to the anterior talocalcanear facette impact-fractures of the anterior part can be expected. These forces develop a posterior directed shear tension parallel to the axis of the os calcis, dividing the bone horizontally in two parts (Typ A, 44-56%), well-known as tongue-type fracture. Compression of the posterior talo-calcaneal joint leads to an impact of this structure producing the joint depression type within about 30 ms in dorsoflexion of the foot (Type B, 42%) together with sagittal shear fractures. High-energy forces are supposed to produce the so-called primary fractures of the sustentacular process in about 10 ms in a supinated position of the foot (Type C, 2-10%); these fractures represent in cases of dislocation an indication for open reduction and internal fixation. In our own experience with 45 cases in 35 patients using the lateral or/and medial approach no infection happened. Palmer's lateral approach was preferred.  相似文献   
84.
85.
This article describes how genetic components of disease susceptibility can be evaluated in case-control studies, where cases and controls are sampled independently from the population at large. Subjects are assumed unrelated, in contrast to studies of familial aggregation and linkage. The logistic model can be used to test collapsibility over phenotypes or genotypes, and to estimate interactions between environmental and genetic factors. Such interactions provide an example of a context where non-hierarchical models make sense biologically. Also, if the exposure and genetic categories occur independently and the disease is rare, then analyses based only on cases are valid, and offer better precision for estimating gene-environment interactions than those based on the full data.  相似文献   
86.
The confrontation with one's body appearance as recorded on a video might have an impact on the body experience of anorexia nervosa patients. Such a video confrontation was applied to a group of 12 anorectic females. After the procedure, these patients rated their actual body (using Osgood's Semantic Differential) as thinner and more active; the control group of 12 female anorectics did not change their evaluations. The patients' evaluation of their ideal body image was not influenced.  相似文献   
87.
Fungal infections still represent a serious complication after organ transplantation. Early diagnosis and aggressive treatment are crucial. Because of the many diagnostic problems involved, we present a case of mucormycosis--primarily affecting the paranasal sinuses with later intracranial extension--in a highly immunized recipient of a third renal transplant. Although fungal infection was suspected from various imaging techniques, only the detection of typical fungal hyphae in the infected tissue was diagnostic. Neither the blood tests and cerebrospinal fluid examinations performed nor cultures from maxillary sinus fluid were of any diagnostic help. Surgical debridement from a transnasal as well as an intracranial approach and systemic amphotericin B together with the discontinuation of immunosuppression after removal of the rejected graft were able to save the patient. This case stresses the importance of early diagnosis that can only be made from tissue biopsies and allows appropriate timely treatment.  相似文献   
88.
This article is a retrospective study comparing the efficacy of Regnauld arthroplasty to first ray osteotomies for the treatment of hallux valgus. One hundred consecutive cases of Regnauld arthroplasties were compared with 100 consecutive first ray osteotomies. One hundred fourty-one patients were available for follow-up, and based on clinical/radiographic examinations, 72 were treated with the osteotomy protocol (group A) and 69 with Regnauld arthroplasty (group B). Age at surgery, clinical symptoms, and preoperative radiologic findings were similar for the 2 groups; there was a preponderance of female patients (90%). The average follow-up was 49 months in group A and 51 months in group B. Clinical evaluation showed in the osteotomy group a more stable correction (79% v 49%), greater pain reduction (measured in a visual analog scale from 0 = pain free to 10 = deep intolerable pain), increased residual articular excursion of the first metatarsophalangeal joint (27 degrees of active dorsiflexion from neutral position v 8 degrees ), and less presence of central metatarsalgia (15% v 34%) (P <.05). The radiographic evaluation expressed more stable correction values in group A for the following parameters: joint preservation, sesamoid position, intermetatarsal angle (7 degrees v 12 degrees ), abduction angle of the hallux (14 degrees v 20 degrees ), and proximal articular set angle (8 degrees v 18 degrees ) (P <.05).  相似文献   
89.
90.
Semliki Forest virus-infected BHK cells or herpes simplex virus-infected Vero cells were incubated with the protein synthesis inhibitors hygromycin B and gougerotin. Infected cells take up no more [3H]hygromycin or [3H]gougerotin than do mock-infected cells, at a time p.i. at which either compound is more inhibitory to protein synthesis in infected, than in mock-infected cells. The concentrations of hygromycin and gougerotin required to inhibit protein synthesis in intact cells (irrespective of whether they are infected or not) are several orders of magnitude higher than those required in either permeabilized cells or in cell-free systems. Infected cells take up 86Rb+ at the same rate as mock-infected cells, their intracellular content of K+ is the same, and the activity of the Na+ pump is the same. It is concluded that the increased efficacy of hygromycin and gougerotin in virus-infected cells is a consequence of altered intracellular compartmentation and that increases in permeability of the plasma membrane, if any, are so small as to be undetectable by direct methods.  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