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   22986篇
  免费   1635篇
  国内免费   65篇
耳鼻咽喉   205篇
儿科学   769篇
妇产科学   656篇
基础医学   2861篇
口腔科学   268篇
临床医学   3354篇
内科学   4231篇
皮肤病学   360篇
神经病学   2164篇
特种医学   554篇
外科学   2495篇
综合类   223篇
一般理论   49篇
预防医学   2917篇
眼科学   307篇
药学   1489篇
  1篇
中国医学   31篇
肿瘤学   1752篇
  2024年   31篇
  2023年   268篇
  2022年   392篇
  2021年   838篇
  2020年   541篇
  2019年   854篇
  2018年   910篇
  2017年   690篇
  2016年   673篇
  2015年   779篇
  2014年   1026篇
  2013年   1389篇
  2012年   2009篇
  2011年   1983篇
  2010年   1093篇
  2009年   892篇
  2008年   1535篇
  2007年   1566篇
  2006年   1367篇
  2005年   1361篇
  2004年   1187篇
  2003年   1022篇
  2002年   920篇
  2001年   124篇
  2000年   71篇
  1999年   113篇
  1998年   198篇
  1997年   173篇
  1996年   135篇
  1995年   80篇
  1994年   67篇
  1993年   76篇
  1992年   29篇
  1991年   36篇
  1990年   28篇
  1989年   33篇
  1988年   25篇
  1987年   21篇
  1986年   24篇
  1985年   25篇
  1984年   16篇
  1983年   16篇
  1982年   14篇
  1981年   8篇
  1980年   15篇
  1979年   3篇
  1978年   3篇
  1977年   8篇
  1976年   8篇
  1975年   6篇
排序方式: 共有10000条查询结果,搜索用时 19 毫秒
71.
BACKGROUND: Boys and young men with hemophilia treated with factor infusions before 1985 had a substantial risk of acquiring the human immunodeficiency virus (HIV) and the acquired immunodeficiency syndrome. This study was designed to assess the effects of HIV and hemophilia per se on neurological function in a large cohort of subjects with hemophilia, and to investigate the relationships between neurological disease and death during follow-up. METHODS: Three hundred thirty-three boys and young men (207 HIV seropositive and 126 HIV seronegative) were evaluated longitudinally in a multicenter, multidisciplinary study. Neurological history and examination were conducted at baseline and annually for 4 years. The relationship between neurological variables, HIV serostatus, CD4+ cell counts, and vital status at the conclusion of the study was examined using logistic regression models. RESULTS: The risks of nonhemophilia-associated muscle atrophy, behavior change, and gait disturbance increased with time in immune compromised HIV-seropositive subjects compared with HIV seronegative or immunologically stable HIV-seropositive subjects. The risk of behavior change in immune compromised HIV-seropositive hemophiliacs, for example, rose to 60% by year 4 versus 10% to 17% for the other study groups. Forty-five subjects (13.5%), all of whom were HIV seropositive, died by year 4. Subjects who died had had increased risks of hyperreflexia, nonhemophilia-associated muscle atrophy, and behavior change. CONCLUSIONS: These results indicate that immune compromised, HIV-seropositive hemophiliacs have high rates of neurological abnormalities over time and that neurological abnormalities were common among subjects who later died. By contrast, immunologically stable HIV-seropositive subjects did not differ from the HIV-seronegative participants. Hemophilia per se was associated with progressive abnormalities of gait, coordination, and motor function.  相似文献   
72.
73.
Objectives: The reconstructed pharyngoesophageal segment (PES) serves as the neoglottis following total laryngectomy, as it provides the source of vibration for production of tracheoesophageal puncture (TEP) voice. To date, little information exists regarding the vibratory characteristics of the PES. The purpose of this investigation was to study the anatomy and physiology of the PES using videostroboscopy. Study Design: Prospective study investigating the anatomy and physiology of the PES in 34 laryngectomees who used TEP speech as their primary form of communication. Materials and Methods: Videostroboscopy and voice recordings were graded by three trained, blinded judges using a seven-point scale. Results: The patients demonstrated differences that allowed for separation of patients into two main groups: “poor” and “effective” TEP speakers. The voice quality differences were explained by anatomic and physiologic characteristics of the PES. Redundant, thick, and dyssynchronous PES features were observed in patients with poor TEP speech skills; the effective speakers exhibited less redundant, thinner mucosa and more synchronous vibratory patterns. Moreover, the latter subgroup consistently demonstrated a greater degree of volitional PES control and less spasmodic activity than their poorly speaking counterparts. Length of the PES opening (measured in the horizontal plane) as well as amount and consistency of secretions did not appear to influence TEP speech or voice proficiency. Conclusion: Videostroboscopy in laryngectomees is a noninvasive, inexpensive, easily performed procedure that may contribute valuable information regarding the anatomy and physiology of the PES, especially in patients who experience difficulties achieving satisfactory TEP voice and speech production.  相似文献   
74.
Objectives: To verify the validity of the recently described sciatic functional index for mice to monitor neuronal functional recovery over time using a blinded, randomized, and controlled evaluation. Study Design: Surgery was performed on the left sciatic nerves of 62 C57/BL mice after randomly assigning them to one of four surgical groups: sham surgery, sciatic nerve crush, nerve transection without repair, and nerve transection followed by epineurial suture repair. Sciatic functional indices were measured before surgery and then after surgery at 10-day intervals for 90 days, using a previously described formula. Results: Sham surgery did not affect nerve function when compared with preoperative values (P > .24). Crush surgery produced a reversible nerve injury that fully recovered after 20 days. Nerve transection without repair resulted in complete functional disability without recovery of function during the 90-day follow-up interval. When transected nerves were repaired, complete functional disability was noted at day 10, with subsequent functional recovery to 26% of function at day 30. This level of recovery persisted until the 60th postoperative day when muscle contractures resulted in progressive worsening of the index. There were statistically significant differences between the sciatic functional indices of each of the groups (P < .05). Conclusions: The previously described sciatic functional index for mice is an accurate indicator of the level of sciatic neuronal function during recovery. This index represents a method of evaluating neuronal function that may provide a better reflection of the recovery parameters that are important in clinical situations. The sciatic functional index will allow for study of sciatic nerve functional recovery in genetically engineered transgenic mice.  相似文献   
75.
76.
77.
OBJECTIVE: To develop a multi-attribute outcome measure for children with asthma that allows for the calculation of quality-adjusted life years in cost-effectiveness studies and can also be used to assign preference weights to asthma-symptom-free days. STUDY DESIGN: A literature review and two interviewer-administered surveys. SETTING: Homes or community centers of participants in Seattle, United States. MAIN MEASURE: Visual analog scale (VAS), standard gamble (SG), and relative risk attitude equation techniques were used to estimate two sets of preference weights for 10 health states. The PAHOM was used to record health states of pediatric asthma patients. RESULTS: A total of 94 subjects provided complete responses without any illogical ratings to VAS questions and 101 provided the same to SG questions. The VAS preference weights of the health states range from a maximum of 1 for perfect health to a minimum of 0.03 for severe asthma symptoms, emotional problems, and activity limitations. Those based on the relative risk attitude equation constructed with both VAS and SG preference weights range from 1 to 0.06. The mean PAHOM scores of pediatric asthma patients based on VAS and converted SG preference weights were 0.70 and 0.83, respectively. CONCLUSIONS: The PAHOM calendar can be used to identify asthma patients' health outcomes, to calculate the preference weights of asthma patients' health states, and to estimate the number of symptom-free days. These factors make the PAHOM a promising instrument for use in effectiveness and cost-effectiveness studies in children with asthma.  相似文献   
78.
INTRODUCTION: Surgical treatment of third nerve palsy, sensory exotropia and strabismus secondary to anomalous innervation of the rectus muscles, frequently require large rectus muscle recessions in an attempt to maintain alignment in the primary position and reduce the effects of misinnervation. The aim of this study was to describe and evaluate the results of inactivation of a rectus muscle by its attachment to the adjacent orbital wall. METHODS: Seven subjects diagnosed with third-nerve palsy (three cases), Duane syndrome (two cases), sensory exotropia (one case), and congenital aberrant innervation of vertical rectus muscles (one case) underwent rectus muscle inactivation by orbital wall fixation. The rectus muscle was disinserted from the globe and reattached to the adjacent orbital periosteum using non-absorbable sutures. This surgery was performed on the lateral rectus muscle in six subjects, and surgery was performed on both ipsilateral vertical rectus muscles in one. RESULTS: Postoperatively four of six patients were aligned within 12 prism diopters of orthotropia in primary position. All patients had improvement of the anomalous head posture. In Duane syndrome, lateral rectus inactivation markedly reduced co-contraction and globe retraction. No overcorrections resulted. CONCLUSION: A rectus muscle may be functionally inactivated when its insertion is attached to the orbital periosteum. Advantages of this procedure over extirpation and free tenotomy include permanent disinsertion of the muscle from globe and reversibility.  相似文献   
79.
80.
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