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   16625篇
  免费   2989篇
  国内免费   139篇
耳鼻咽喉   446篇
儿科学   485篇
妇产科学   453篇
基础医学   1206篇
口腔科学   239篇
临床医学   3878篇
内科学   2947篇
皮肤病学   429篇
神经病学   1552篇
特种医学   467篇
外科学   2066篇
综合类   402篇
现状与发展   2篇
一般理论   9篇
预防医学   2741篇
眼科学   211篇
药学   681篇
  1篇
中国医学   104篇
肿瘤学   1434篇
  2024年   95篇
  2023年   502篇
  2022年   251篇
  2021年   560篇
  2020年   673篇
  2019年   464篇
  2018年   910篇
  2017年   808篇
  2016年   855篇
  2015年   983篇
  2014年   1073篇
  2013年   1511篇
  2012年   1097篇
  2011年   1014篇
  2010年   880篇
  2009年   931篇
  2008年   805篇
  2007年   759篇
  2006年   731篇
  2005年   628篇
  2004年   489篇
  2003年   396篇
  2002年   348篇
  2001年   217篇
  2000年   135篇
  1999年   179篇
  1998年   325篇
  1997年   324篇
  1996年   332篇
  1995年   266篇
  1994年   186篇
  1993年   139篇
  1992年   98篇
  1991年   90篇
  1990年   76篇
  1989年   93篇
  1988年   74篇
  1987年   57篇
  1986年   50篇
  1985年   53篇
  1984年   50篇
  1983年   43篇
  1982年   34篇
  1981年   48篇
  1980年   19篇
  1979年   11篇
  1978年   16篇
  1977年   15篇
  1976年   14篇
  1975年   11篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
There is an ongoing debate in nurse education concerning the role and delivery of the biological sciences in the nursing curriculum. One of the fundamental questions raised by this debate asks how best can teachers impart biological knowledge in a manner that can be readily applied by students and qualified nurses to inform their clinical practice. This paper will include a discussion of some of the features of pre-registration education that may have influenced the manner in which biological sciences are perceived, taught and used by nurses. It will be argued that nursing may have developed a form of incomplete holism and that this may be in part responsible for the challenges that remain to be met within this area of the nursing curriculum. As a response to incomplete holism an innovative approach within pre-registration education will be introduced. This development involves the use of linked teaching sessions which aim to develop the analytical skills necessary to apply physiological knowledge to nursing practice.  相似文献   
42.
This is the first of two papers which address aspects of the findings of a large scale study commissioned by the English National Board which set out to examine the impact of Project 2000 on perceptions of the philosophy and practice of nursing. The findings presented here suggest that there have been fundamental shifts in perceptions of the nature and discipline of nursing. Students and diplomates of the course perceive themselves as knowledgeable doers, with their practice well grounded in theory and research. They value the interpersonal skills teaching and place the patient firmly at the centre of care delivery, viewing the patient holistically and being prepared to be fierce patient advocates where necessary. It is difficult to determine the extent to which these shifts can be attributed to the Project 2000 course, although the Project 2000 approach to education appears to be an important factor.  相似文献   
43.
Summary: regnant women who attended antenatal clinics at King George V Hospital, the Birth Centre or were referred by obstetricians from February to July. 1996 were screened for the platelet antigen HPA-la by flow cytometry. Forty out of 2300 (1.7%) were found to be negative for this antigen . Of the 28 women followed throughout their pregnancy, none developed antibody to HPA-la. Platelet counts performed on samples from 17 babies born to 17 of these mothers were all normal. This study proves the simplicity and rapidity of flow cytometry for platelet antigen screening. The results were comparable with the Solid Phase Red Cell Adherence (SPRCA) method and with PCR. The lack of a plentiful supply of specific antibody and the rarity of fetomaternai alloimmune thrombocytopenia (FMAIT) argue against the introduction of routine screening for maternal HPA-la status at the present time.  相似文献   
44.
Background: Secondary insults/complications have a major impact on the prognosis after traumatic brain injury (TBI). The aim was to study the occurrence and prognostic value of secondary insults occurring in TBI patients, during standardized neurointensive care (NIC) dedicated to avoiding secondary insults. Material and Methods: 154 patients, 17-79 years, with acute head trauma and pathologic CT, treated during a 2-year period at the NIC unit were studied. The occurrence of defined secondary insults (standard and severe) was recorded during the 1st week of NIC from bedside surveillance charts containing one value per hour and parameter (intracranial pressure, cerebral perfusion pressure, systolic blood pressure, PaO2, temperature, and blood glucose). The data set was analyzed using univariate and multivariate logistic regression with favorable outcome as the response variable. Both admission variables (Glasgow Coma Scale Motor Score [GCS M], CT class, Injury Severity Score [ISS], age, and gender) and secondary insult variables were included as explanatory variables. Results: In total, 1,570 insults were identified (320 severe). In the univariate analysis, the sum of all insults, blood glucose, GCS M, CT class, and ISS showed significant effects on outcome (p < 0.05). In the multiple regression analysis, GCS M was the only significant explanatory variable. Conclusions: The occurrence of secondary insults in the NIC unit was not negligible, despite the fact that major efforts were made to avoid them. The sum score of all insult categories and high blood glucose had a statistically significant effect on favorable outcome in the univariate analysis, but secondary insults did not add any prognostic information to the neurologic grade in the multivariate analysis. This finding indicates that the insults that occurred were related to the degree of primary injury/neurologic grade.  相似文献   
45.
Nephrectomy during operative management of retroperitoneal sarcoma   总被引:4,自引:0,他引:4  
Background: Complete resection of a retroperitoneal sarcoma often requires removal of adjacent organs. In this study we evaluated the role of nephrectomy during operation for retroperitoneal sarcoma. Methods: Between July 1982 and July 1995, 75 of the 371 (20%) patients who underwent resection of retroperitoneal sarcoma at MSKCC underwent concommitant nephrectomy. Data concerning the reasons for nephrectomy, degree of sarcomatous renal involvement, and survival were retrospectively analyzed. Results: Fifty-four patients (72%) underwent nephrectomy during the initial resection, and 21 (28%) during a resection of a recurrent or persistent tumor. The most common reason for nephrectomy was total encasement by sarcoma (n=40; 53%), followed by dense adherence of the tumor to the kidney (n=21; 28%), and the direct invasion of the kidney by tumor (n=2; 3%). Pathology demonstrated an absence of kidney invasion in the majority of cases (55 of 75; 73%). Renal capsular invasion was present in 11 of 75 (15%), renal parenchymal invasion in 7 of 75 (9%), and renal vein invasion in 2 of 75 (3%) of cases. There were no significant differences in survival based on degree of sarcoma involvement of the kidney, tumor grade, or whether the resection was for primary or recurrent disease. The 53 patients who underwent a complete gross resection of all tumor had a significantly improved long-term survival compared to the 20 patients who did not (50% versus 20% DFS at 5 years, respectively; p<0.001). Conclusions: Decisions for concomitant nephrectomy during resection of retroperitoneal sarcoma should be based on whether this maneuver will provide a complete resection of all gross tumor, in which case the long-term disease-free survival of 50% is comparable to the reported 5-year survival of all patients with retroperitoneal sarcoma who are completely resected. Presented at the 49th Annual Cancer Symposium of the Society of Surgical Oncology, Atlanta, Georgia, March 21–24, 1996.  相似文献   
46.
The present study describes, in animals, a novel approach to the in vivo, noninvasive determination of alcohol in the body. The concentration of ethanol in vapor above the lacrimal fluid in the eye was analyzed in situ by the use of a fast (1-min) gas sensor method developed previously for biological liquids. After an oral dose of 1 g/kg to 11 animals, eye vapor measurements and blood samples were obtained over 4 hr. The correlation of 61 blood ethanol concentrations obtained by the two methods yielded a correlation coefficient of 0.92 and a slope of 0.99. The metabolic rates of ethanol determined by gas chromatographic analysis of blood and by ethanol eye vapor analysis are virtually identical. The data suggest that ethanol eye vapor analysis may be an attractive, noninvasive method for the determination of ethanol in animals. The method is not subject to false high readings due to alcohol in the buccal cavity and thus might constitute an alternative to breath analysis in the human. In a separate series, ethanol was determined by head space gas chromatography in samples of blood and lacrimal fluid while the animals were under ketamine anesthesia. The correlation of ethanol concentrations in blood and lacrimal fluid (r = 0.99) shows that ethanol is distributed in lacrimal fluid which comprises part of total body water.  相似文献   
47.
This paper reflects on a research project funded by a consortium of leading sheltered housing (SH) providers and their regulatory body, the Housing Corporation. The project aimed to ascertain which aspects of SH older people perceived to be central to their satisfaction and the methods they judged most appropriate to measuring this. We outline key policy developments of importance to SH (specifically the development of performance measurement regimes), and changes in the nature of SH, which are driving providers to re‐evaluate how they measure user satisfaction. We discuss the aims of the project, our methodology and findings, and conclude by raising critical questions about the process of measuring satisfaction within an increasingly managerialised housing system. We argue that this favours standardised methods of information gathering (such as questionnaires) rather than engage with clients in order to develop methods and systems capable of eliciting qualitative issues of concern to them. Our conclusions are, we believe, applicable to health and social care provision, where similar tensions exist around performance measurement and user satisfaction.  相似文献   
48.
Background. Vitiligo is an acquired skin disorder that is characterized by well-defined, often symmetric white patches. Although current therapeutic modalities are directed toward increasing melanocyte melanin production, few treatment modalities address the immunologic nature of the disease.
Objective. To determine whether excimer laser, a known therapeutic modality, in combination with tacrolimus, a topical immunomodulator, accelerate response time and/or improve the degree of response in patients with this disorder.
Methods. Eight subjects diagnosed with vitiligo were recruited to participate in this institutional review board–approved double-blind, placebo-controlled study. Twenty-four symmetric vitiliginous patches (elbows, knees) from eight subjects received excimer laser treatment three times per week for 24 treatments or 10 weeks. Additionally, topical tacrolimus 0.1% ointment (Protopic) and placebo (Aquaphor) were applied to randomized patches (left or right) twice daily throughout the length of the trial. Vitiliginous patches were monitored with photographs at baseline, every 2 weeks, and 6 months after treatment. Biopsies were performed on subjects with significant results.
Results. Twenty vitiliginous patches from six subjects qualified for evaluation. Fifty percent of patches treated with combination excimer laser and tacrolimus achieved a successful response (75% repigmentation) compared with 20% for the placebo group. Subjects who responded successfully repigmented faster (19%) with combination therapy compared with excimer laser alone. Additionally, three subjects experienced transient hyperpigmentation in lesions treated with combination therapy.
Conclusion. Combining topical immunomodulators with known phototherapeutic modalities may represent a key advancement in the treatment of disease.  相似文献   
49.
The purpose of this study was to examine motor learning and retention given extensive practice in two fundamentally different movement sequences. One sequence was a memory-driven task (performing a series of whole body positions from memory) and the other a context-driven task (buttoning). Practice took place over 3 weeks, with performance measured weekly; retention was measured weekly for 3 weeks after practice. There were 7 people with Parkinson's disease (PD) and 7 age-matched neurologically healthy people who participated in this study. Both groups improved performance on both tasks with practice, with the majority of the change for the PD group occurring between 1 and 2 weeks of practice. Although those with PD did not necessarily perform as well as age-matched controls, they learned both sequences in a manner similar to age-matched controls, and exhibited retention across the 3-week retention interval. If people with PD are given sufficient practice they can learn and retain both memory-based and context-driven movement sequences as well as age-matched controls. The results provide support for maintaining physical activity and for intervention through movement therapy.  相似文献   
50.
The receptor tyrosine kinase (RTK) Ret is activated by the formation of a complex consisting of ligands such as glial cell line-derived neurotrophic factor (GDNF) and glycerophosphatidylinositol-anchored coreceptors termed GFRalphas. During activation, Ret translocates into lipid rafts, which is critical for functional responses to GDNF. We found that Ret was rapidly ubiquitinated and degraded in sympathetic neurons when activated with GDNF, but, unlike other RTKs that are trafficked to lysosomes for degradation, Ret was degraded predominantly by the proteasome. After GDNF stimulation, the majority of ubiquitinated Ret was located outside of lipid rafts and Ret was lost predominantly from nonraft membrane domains. Consistent with the predominance of Ret degradation outside of rafts, disruption of lipid rafts in neurons did not alter either the GDNF-dependent ubiquitination or degradation of Ret. GDNF-mediated survival of sympathetic neurons was inhibited by lipid raft depletion, and this inhibitory effect of raft disruption on GDNF-mediated survival was reversed if Ret degradation was blocked via proteasome inhibition. Therefore, lipid rafts sequester Ret away from the degradation machinery located in nonraft membrane domains, such as Cbl family E3 ligases, thereby sustaining Ret signaling.  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