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   1793篇
  免费   93篇
  国内免费   9篇
耳鼻咽喉   13篇
儿科学   79篇
妇产科学   32篇
基础医学   336篇
口腔科学   29篇
临床医学   117篇
内科学   269篇
皮肤病学   32篇
神经病学   312篇
特种医学   54篇
外科学   209篇
综合类   6篇
预防医学   69篇
眼科学   91篇
药学   134篇
中国医学   11篇
肿瘤学   102篇
  2022年   14篇
  2021年   34篇
  2020年   17篇
  2019年   33篇
  2018年   47篇
  2017年   30篇
  2016年   43篇
  2015年   47篇
  2014年   46篇
  2013年   77篇
  2012年   99篇
  2011年   90篇
  2010年   54篇
  2009年   60篇
  2008年   79篇
  2007年   77篇
  2006年   93篇
  2005年   71篇
  2004年   71篇
  2003年   57篇
  2002年   67篇
  2001年   22篇
  2000年   21篇
  1999年   22篇
  1998年   23篇
  1997年   9篇
  1992年   10篇
  1989年   8篇
  1988年   9篇
  1939年   8篇
  1937年   9篇
  1936年   10篇
  1934年   9篇
  1933年   14篇
  1932年   12篇
  1931年   13篇
  1930年   15篇
  1929年   15篇
  1928年   19篇
  1927年   18篇
  1926年   16篇
  1925年   22篇
  1924年   24篇
  1923年   16篇
  1922年   16篇
  1921年   10篇
  1911年   11篇
  1908年   9篇
  1905年   9篇
  1902年   8篇
排序方式: 共有1895条查询结果,搜索用时 31 毫秒
1.
Zusammenfassung In vorliegender Arbeit konnten wir die Anwendbarkeit unserer in der vorigen Mitteilung für tensioaktive Gifte und antekritische Vergiftungssymptome abgeleiteten Vergiftungsgleichungen auf die Ergebnisse unserer mit Saponin an Atherina hepsetus L. ausgeführten Vergiftungsversuche (vgl. III. Mitteilung) bestätigen.Mit 1 Textabbildung.VII. Mitteilung: Naunyn-Schmiedebergs Arch.191, 628 (1939).  相似文献   
2.
3.
4.
Placenta can be considered as a pump of calcium necessary for the normal development of the fetus. We believe that the location of this pump is in the placental basement membrane. The calcification of this membrane has been described only in cases of in utero fetal death. In this study we describe for the first time a case of placental calcification in a living fetus. The fetus of a normal 21-year-old pregnant woman showed heart abnormalities but the genetic analysis showed a normal male karyotype. The histology of the placenta demonstrated multiple intravillous linear and granular calcific incrustations The hemtoxylin/eosin stain of the sections revealed basement membrane calcific incrustations and intravillous calcium deposits. We postulate that the fetal circulation in the villi was impaired and the calcium that reached the villi from the mother was deposited at this level.  相似文献   
5.
ABSTRACT: Background: Increasingly, women seek involvement in decisions about their health care. The purpose of this study was to examine women's experience of, and satisfaction with, their involvement in health care decisions during a high‐risk pregnancy. Methods: Forty‐seven women with hypertension or threatened preterm delivery (including multiple births) were interviewed after the birth of their child. They received prenatal care at home from nurses in a community program or were hospitalized. The in‐depth interviews were audiotaped and transcribed; data were analyzed using constant comparative methods. Results: Women identified an increased feeling of responsibility for the health of their baby and themselves, but differed in choosing active or passive involvement in health care decisions. Women who wanted active involvement achieved it through one of three processes: struggling for, negotiating, or being encouraged. Women who wanted passive involvement and women facing health crises used the process of trusting in the expertise of nurses and physicians. Women were satisfied if the care from health care professionals was congruent with how they wanted to be involved in decision‐making. Conclusions: Although most women want to be actively involved in health decision‐making during a high‐risk pregnancy, some prefer a passive role. The setting of prenatal care, community‐based or in‐hospital, was less important than the ability of nurses and physicians to support the woman in her preferred role in decision‐making. (BIRTH 30:2 June 2003)  相似文献   
6.
Summary Intracellular concentrations of prednimustine (PM), chlorambucil (CLB), phenylacetic acid mustard (PAAM) and prednisolone (P) were measured in different experimental tumor cell lines that had been incubated with either PM or CLB+P. For intracellular analytical determination, we modified a high-pressure liquid chromatographic method for the detection of these substances in plasma. Intact PM could be detected in the intracellular compartment of the incubated tumor cells. PM-incubated cells from PM-injected rats exhibited a higher intracellular concentration-time integral (PAAM) and longer concentration-time profiles for drugs with alkylating capacity than did cells exposed to the CLB+P mixture or to CLB. PAAM was not detectable after incubation of cells with PM, whereas in CLB-incubated cells the AUC of PAAM exceeded that of the parent drug CLB. Our in vitro results therefore favour the concept of a facilitated intracellular uptake and an increased antiproliferative effect for PM versus CLB and CLB+P.Dedicated to Prof. Dr. H. J. Dengler on the occasion of his 65th birthday. This study was supported by the Ministry of Science and Research of Nordrhein-Westfalen  相似文献   
7.
The purpose of this study was to explore the relationship between carpal tunnel pressure and fingertip force during a simple pressing task. Carpal tunnel pressure was measured in 15 healthy volunteers by means of a saline-filled catheter inserted percutaneously into the carpal tunnel of the nondominant hand. The subjects pressed on a load cell with the tip of the index finger and with 0, 6, 9, and 12 N of force. The task was repeated in 10 wrist postures: neutral; 10 and 20° of ulnar deviation; 10° of radial deviation; and 15, 30, and 45° of both flexion and extension. Fingertip loading significantly increased carpal tunnel pressure for all wrist angles (p = 0.0001). Post hoc analyses identified significant increases (p <0.05) in carpal tunnel pressure between unloaded (0 N) and all loaded conditions, as well as between the 6 and 12 N load conditions. This study demonstrates that the process whereby fingertip loading elevates carpal tunnel pressure is independent of wrist posture and that relatively small fingertip loads have a large effect on carpal tunnel pressure. It also reveals the response characteristics of carpal tunnel pressure to fingertip loading, which is one step in understanding the relationship between sustained grip and pinch activities and the aggravation or development of median neuropathy at the wrist.  相似文献   
8.
BACKGROUND: There is a lack of information from Canadian hospitals on the role of hospital characteristics such as procedure volume and teaching status on the survival of patients who undergo major cancer resection. Therefore, we chose to study these relationships using data from patients treated in Ontario hospitals. METHODS: We used the Ontario Cancer Registry from calendar years 1990-2000 to obtain data on patients who underwent surgery for breast, colon, lung or esophageal cancer or who underwent major liver surgery related to a cancer diagnosis between 1990 and 1995 in order to assess the influence of volume of procedures and teaching status of hospitals on in-hospital death rate and long-term survival. For each disease site and before observing patient outcomes data, volume cut-off points were selected to create volume groups with similar numbers of patients. Teaching hospitals were those directly affiliated with a medical school. Logistic regression and proportional hazards models were used to consider the clustering of data at the hospital level and to assess operative death and long-term survival. We also used 4 measures to gauge the degree of procedure regionalization across the province including (1) the number of hospitals performing a procedure; (2) the percentage of patients treated in teaching hospitals; (3) the percentage of rural patients treated in higher volume procedure hospitals; and (4) median distances travelled by patients to receive care. RESULTS: The number of patients in our cohorts who underwent resection of the breast, colon, lung, esophagus or liver was 14 346, 8398, 2698, 629 and 362, respectively. Surgery in a high-volume versus a low-volume hospital did not have a statistically significant influence on the odds of operative death for patients who underwent colon, liver, lung or esophageal cancer resection. The risk of long-term death was increased in low-volume versus high-volume hospitals for patients who underwent resection of the breast (hazard ratio [HR] 1.2, 95% confidence interval [95% CI] 1.0-1.4, p < 0.05), lung (HR 1.3, 95% CI 1.1-1.6, p < 0.01) and liver (HR 1.7, 95% CI 1.0-2.7, p = 0.04). There were no significant differences in the odds of operative (in-hospital) death or risk of long-term death among patients treated in teaching compared with nonteaching hospitals. There was more regionalization of liver, lung and esophageal operations versus breast and colon operations. CONCLUSIONS: Increased hospital procedure volume correlated with improved longterm survival for patients in Ontario who underwent some, but not all, cancer resections, whereas hospital teaching status had no significant impact on patient outcomes. Across the province, further regionalization of care may help improve the quality of some cancer procedures.  相似文献   
9.
Ohne Zusammenfassung (Mit 4 Abbildungen.) Nach einer klinischen Demonstration der Schweiz. neurolog. Gesellschaft zu Basel, 12. Nov. 1910.  相似文献   
10.
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