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   11112篇
  免费   2708篇
  国内免费   59篇
耳鼻咽喉   155篇
儿科学   281篇
妇产科学   336篇
基础医学   494篇
口腔科学   415篇
临床医学   3660篇
内科学   1868篇
皮肤病学   334篇
神经病学   1255篇
特种医学   257篇
外科学   1889篇
综合类   53篇
预防医学   1493篇
眼科学   438篇
药学   222篇
中国医学   10篇
肿瘤学   719篇
  2024年   84篇
  2023年   491篇
  2022年   121篇
  2021年   295篇
  2020年   401篇
  2019年   207篇
  2018年   731篇
  2017年   760篇
  2016年   694篇
  2015年   721篇
  2014年   861篇
  2013年   920篇
  2012年   446篇
  2011年   463篇
  2010年   581篇
  2009年   728篇
  2008年   407篇
  2007年   318篇
  2006年   338篇
  2005年   301篇
  2004年   235篇
  2003年   224篇
  2002年   210篇
  2001年   249篇
  2000年   118篇
  1999年   214篇
  1998年   280篇
  1997年   262篇
  1996年   323篇
  1995年   232篇
  1994年   227篇
  1993年   173篇
  1992年   154篇
  1991年   134篇
  1990年   87篇
  1989年   95篇
  1988年   85篇
  1987年   86篇
  1986年   79篇
  1985年   59篇
  1984年   45篇
  1983年   40篇
  1982年   45篇
  1981年   23篇
  1980年   35篇
  1979年   26篇
  1978年   23篇
  1977年   18篇
  1975年   18篇
  1972年   20篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Fifty-six children with isolated growth hormone deficiency (IGHD) and their families completed self-report instruments about behavioral, social, and emotional adjustment of the children. Results show that children with IGHD may experience significant behavioral and social adjustment problems. Social and emotional adjustment was best predicted by the relative height discrepancy between an individual and their normal-sized peers. Adjustment varied depending on the type of adjustment under consideration, the relative height discrepancy of the individual, the age and gender of the child, and the amount of time in treatment. Discussion addresses the need for an interdisciplinary approach to effective patient management of children with IGHD.  相似文献   
82.
The computerized database system described was initially developed in 1986 to facilitate analysis of retrospective head and neck cancer data from the Royal Adelaide Hospital Department of Otolaryngology. This has now been expanded to become an on-going patient information management system. It is based on the dBase-III-Plus database package and is implemented on an IBM XT compatible computer. The system was designed to be used by staff without specialist computer skills and is therefore largely “menu-driven.” The main functions include patient record creation, update, and retrieval, and the production of reports including graphical presentations. There is also a powerful but easy to use query facility. The system has already provided much useful epidemiological material but is now beginning to fulfill an even more important role in patient follow-up and in assisting evaluation of alternative treatment protocols.  相似文献   
83.
This study was designed to assess the accuracy of end-tidalPco 2 and transcutaneousPco 2 as measurements of arterialPco 2 in extubated, spontaneously breathing patients recovering from general anesthesia. In 30 patients, measurement of arterial transcutaneous, and end-tidalPco 2 were taken simultaneously with body temperature approximately every 15 minutes over a 2-hour period. ArterialPco 2 values were corrected for body temperature. Values for Paco 2 were compared with those forPetCO2 and Psco 2 by linear regression analysis and by calculation of bias ± precision. Thirty-six percent of the capnogram tracings obtained did not develop a plateau phase. We found poor correlation between end-tidal and arterialPco 2 regardless of the shape of the capnogram tracing, as well as poor correlation between transcutaneous and arterialPco 2. Although the measurements of bias and precision of noninvasivePco 2 monitors in this population are comparable to studies in other populations, we advise caution in relying on the routine use ofPetCO2 or Psco 2 for the noninvasive assessment of respiratory depression in extubated, spontaneously breathing patients recovering from general anesthesia.  相似文献   
84.
The ability of bone cements to modify the apoptotic program in activated immune cells and the mechanisms by which they act were evaluated. Mononuclear cells were collected from healthy individuals, cultured for 4 and 24 h with phytohemoagglutinina-P and cement extracts and then tested to assess: (a) cell viability; (b) early apoptotic events, by Annexin V/propidium iodide staining; and (c) the expression of pro- (p53, c-myc, ICE) and anti-apoptotic (bcl-2) genes. After 4 h three cements were able to increase significantly the percentage of apoptotic cells, while after 24 h no differences were found. The proportion of dead cells was not significantly changed at either culture time. The simultaneous expression of both pro-apoptotic (ICE, c-myc, p53) and antiapoptotic genes (bcl-2) was investigated only with regard to the materials which induced significant changes in apoptosis: two cements induced the p53 expression, while the third down-regulated bcl-2. As apoptosis regulates the balance of immune response, the authors recommend that the interaction between materials and immune cells should be assessed, so that the use of pro-apoptotic materials may be avoided in patients with immune defects.  相似文献   
85.
BACKGROUND: Although mixed states were classically described as various concomitant admixtures of depression and mania, the official current definitions in both DSM-IV and ICD-10 tend to restrict the concept to manic patients with full syndromal depression. Recent research has actually shown that mania with few depressive symptoms constitutes the most prevalent clinical presentation of mixed or dysphoric mania. Major depressive patients with few concomitant manic symptoms are not officially recognized within the current nosology. In this paper we attempt to delineate the clinical profile of such depressive mixed states in the context of bipolar I disorder. METHODS: In the Pisa day center, we studied 195 bipolar I patients who either met Pisa criteria for bipolar mixed state (n=159) or DSM-III-R criteria for major depressive episode (bipolar major depression or B-MD, n=36). Of the 159 patients identified by Pisa criteria as mixed state, 86 also met the criteria of the DSM-III-R for mixed episode (core mixed state or MS group), while 32 met the DSM III-R criteria for major depressive episode (provisionally defined as depressive mixed states, D-MS); the remaining patients (n=41, 25.7%) with predominatly manic picture were not included in the present comparisons. RESULTS: The three groups (B-MD, MS and D-MS) had close similarities in clinical and sociodemographic characteristics such as age, sex distribution, marital status, schooling, residence, age at onset, age of first treatment, age of first hospitalization, degree of chronicity of the index episode, stressor within the 6 months before the index episode, lifetime suicide attempts and premorbid temperament. First degree family history for bipolar illness and that for other mental disorders was also similar, except for major depression that was more common among the relatives of D-MS. MS and D-MS were further distinguished from B-MD by the fact that the latter followed a more 'cyclic' course with shorter yet greater number of episodes, and which began with a pure depressive episode; by contrast, MS and D-MS had fewer episodes of longer duration, less interepisodic remission, and tended to begin with a mixed episode. Incongruous psychotic features were more common in the two mixed groups compared to B-MD, and the most common features of the D-MS group were agitation, psychotic depression with irritable mood, pressured speech and/or flight of ideas. LIMITATION: It was not feasible to collect information blind to clinical status in patients with severe psychotic mood states. CONCLUSION: These data confirm the existence of psychotic agitated depressive mixed states with flight of ideas, distinct from cyclic retarded pure bipolar depressive states. The recognition of these affective states is clinically important to protect patients from the potentially harmful indiscriminate use of antidepressants and to provide them with the benefits of an anticonvulsant, a short-term neuroleptic, or ECT.  相似文献   
86.
A new hybrid fixation stem, named cemented-locked uncemented (CLU), for total hip arthroplasty was developed to achieve good initial stability. Primary stability is guaranteed by the cement which is injected into two pockets in the lateral area. This leaves a large surface available for long-term biologic fixation (direct bone attachment on implant). This study evaluates in vitro the initial stability of the CLU prototype under torsional load, in comparison with cemented and cementless stems. The results show that the CLU stem is very stable in simulated stair climbing. Its micromotions are comparable to those of a cemented prosthesis, and significantly less (80-90% lower) than those for a cementless stem. These findings confirm the optimal initial stability expected from the CLU prototype. This new design, which employs hybrid fixation, should improve bone formation on the implant and reduce the risk of stem loosening.  相似文献   
87.
Frequent spontaneous deletions at a shuttle vector locus in transgenic mice   总被引:2,自引:0,他引:2  
Transgenic mice carrying multiple copies of a recoverable lambdaphage shuttle vector (  相似文献   
88.
N-I Max Kjellman  MD  PhD    Michael T Stevens  BSc  CStat   《Allergy》1995,50(S21):14-22
A programme of clinical studies was carried out to determine the basic efficacy and safety of 2% nedocromil sodium eye drops (Tilavist) in treating allergic conjunctivitis, in 2,905 patients from 3–76 years of age. Results of all the double-masked placebo comparative studies completed to date - five in vernal keratoconjunctivitis (VKC), five in perennial (PAC) and 16 in seasonal allergic conjunctivitis (SAC) - have been assessed in a statistical overview analysis. Nedocromil sodium, administered four times daily to 153 patients with VKC, was significantly more effective than placebo (155 patients) and in the clinicians' opinion gave good control in 76% of cases, compared with 46% for placebo (p < 0.001). Patients with chronic symptoms of PAC also responded better to nedocromil sodium given four times daily (n = 146) rather than twice daily (n = 86), and significantly more patients (p < 0.001) were effectively controlled by four times daily treatment with nedocromil sodium (72%) than with placebo (47%; n= 156). Twice-daily dosage with nedocromil sodium (n = 677) was adequate for SAC, however, and the treatment was statistically better than placebo (p < 0.01-p < 0.001) whether dosed twice or four times daily. Speed of action was assessed in seven SAC studies in which 79% of all patients (n = 295) using nedocromil sodium had experienced relief of symptoms when questioned, half of them within 15 minutes and 74% during the first hour after dosing. Test treatments were well-accepted by both adults and children, and there were no major adverse events. Minor irritations reported more frequently with nedocromil sodium than placebo were stinging or burning of the eyes on application of the drops and a distinctive taste, noted by 5% of the active treatment group (n = 1,552).  相似文献   
89.
This work describes our experience in reviewing the performance criteria for display systems and how we have implemented a practical approach to the assessment of the workstation environment in a large tertiary care hospital. The acceptance criteria contained in the draft report of Topic Group 18 of the American Association of Physicists in Medicine (AAPM) were used as a basis for assessment of primary and secondary displays. A telescopic photometer was used to measure the maximum luminance and the contrast ratio of the image for the displays used in our radiology department and in the operating and emergency rooms using the standard Society of Motion Picture and Television Engineers (SMPTE) pattern, in ambient light and with light decreased as much as possible. About half of the displays met the AAPM criteria for minimum luminance and contrast ratio in low light. None of the systems met the contrast ratio criteria in ambient light. The challenges in improving the performance and calibrating displays are discussed.  相似文献   
90.
Recent advances in automatic speech recognition and related technologies allow computers to carry on conversations by telephone. We developed an intelligent dialogue system that interacts with hypertensive patients to collect data about their health status. Patients thus avoid the inconvenience of traveling for frequent face to face visits to monitor the clinical variables they can easily measure at home; the physician is facilitated in acquiring patient information and cardiovascular risk, which is evaluated from the data according to noted guidelines. Controlled trials to assess the clinical efficacy are under way.  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