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   201560篇
  免费   4274篇
  国内免费   470篇
耳鼻咽喉   3024篇
儿科学   8261篇
妇产科学   6141篇
基础医学   25400篇
口腔科学   6317篇
临床医学   15630篇
内科学   35995篇
皮肤病学   4748篇
神经病学   11953篇
特种医学   10942篇
外国民族医学   97篇
外科学   30971篇
综合类   1348篇
一般理论   5篇
预防医学   16428篇
眼科学   4547篇
药学   13771篇
  2篇
中国医学   221篇
肿瘤学   10503篇
  2018年   3690篇
  2017年   4039篇
  2016年   3352篇
  2015年   4980篇
  2014年   4490篇
  2013年   3736篇
  2012年   10093篇
  2011年   5081篇
  2010年   2400篇
  2009年   3990篇
  2008年   2407篇
  2007年   3148篇
  2006年   3429篇
  2005年   11573篇
  2004年   13072篇
  2003年   8703篇
  2002年   3942篇
  2001年   4721篇
  2000年   2052篇
  1999年   6078篇
  1998年   624篇
  1996年   460篇
  1992年   6869篇
  1991年   7099篇
  1990年   7345篇
  1989年   6945篇
  1988年   6469篇
  1987年   6232篇
  1986年   5950篇
  1985年   5243篇
  1984年   3591篇
  1983年   2910篇
  1982年   1001篇
  1981年   771篇
  1980年   837篇
  1979年   3832篇
  1978年   2363篇
  1977年   1785篇
  1976年   1559篇
  1975年   2474篇
  1974年   3109篇
  1973年   2739篇
  1972年   2762篇
  1971年   2743篇
  1970年   2556篇
  1969年   2464篇
  1968年   2238篇
  1967年   2164篇
  1966年   1898篇
  1965年   1131篇
排序方式: 共有10000条查询结果,搜索用时 906 毫秒
121.
The effect of unilateral ureteral occlusion on fibrin deposition in the kidney and the interrelation of the fibrin deposition and the renal blood flow was studied in rat. Intravascular coagulation in the kidney was induced by infusion of thrombin and inhibition of fibrinolysis with tranexamic acid. The effects unilateral occlusion of the ureter for 1 and 24 h on fibrin deposition and renal blood flow were studied. Fibrin in the kidneys was quantitated by intravenous injection of 125I-labelled fibrinogen 24 h before the experiment. The renal blood flow was measured before and after infusion of thrombin by injection of 85Sr- and 141Ce-labelled microspheres into the left ventricle. After ureteral occlusion for 1 h the deposition of fibrin in the kidneys was unaffected. After 24 h substantially less fibrin deposition was found in the occluded than in the unoccluded kidney (0.3 +/- 0.2 and 5.7 +/- 1.6 mg, respectively; p less than 0.05). Before thrombin infusion the blood flow to the occluded kidney was less than that in the unoccluded kidney (2.1 +/- 0.8 and 3.7 +/- 1.2 ml/min, 100 g body weight, respectively; p less than 0.05). The blood flow after infusion of thrombin was equally reduced in both kidneys. The results contradict the hypothesis that vasoconstriction increases the amount of fibrin in the kidneys in thrombin-induced intravascular coagulation.  相似文献   
122.
We found that thirteen per cent of all head and neck malignomas are malignant lymphomas. In 75% of these cases the Non-Hodgkin type could be found. The major salivary glands were involved by the lymphoma in 55% out of 104 patients. Paraglandular lymph nodes of the parotid gland were affected as well as intraglandular lymph nodes and the lymphoid tissue within the gland proper. The submandibular gland normally shows an involvement only with its paraglandular lymph nodes. Two thirds of the Non-Hodgkin lymphomas located in the salivary glands were low-grade. In case of clinical suspicion of a malignant lymphoma, fine needle biopsy is required for cytological diagnosis. However, surgery is mandatory for histological diagnosis, not as a therapeutic measure.  相似文献   
123.
124.
125.
126.
Irradiation of a cytosolic fraction from vascular smooth muscle in the presence of [3H]felodipine resulted in the labelling of a protein with an apparent molecular weight of 62 kDa. The labelling was seen on UV-irradiation at 360 nm, but not at 254, 278 or at wavelengths above 410 nm. The photolabelling was enhanced in the absence of oxygen. In cytosolic fractions prepared from porcine liver, cardiac and skeletal muscle no photoaffinity labelling of proteins between 90 and 45 kDa could be demonstrated. The results suggest that felodipine is a photoaffinity ligand and that felodipine binds to a soluble protein present in vascular smooth muscle but not in the other tissues tested.  相似文献   
127.
A new technique for ultrasonic examination of the hip joint was evaluated in neonatals and infants. An anterior approach was used with the sound sector centered over the femoral head and parallel to the femoral neck. The ultrasonograms corresponded to lateral radiographs of the joint with the leg in Lorenz' first position. It was possible to evaluate the size and depth of the acetabulum and the size and position of the femoral head. The projection also permitted a dynamic examination for determination of hip instability. Thus, the technique provided a method for an objective diagnosis in congenital dislocation of the hip (CDH). In 216 hips, the results of clinical evaluation for CDH were correlated with the degree of instability demonstrated by ultrasound. The comparison showed the clinical diagnosis to be highly inaccurate.  相似文献   
128.
129.
PURPOSE: The purpose to clarify what kind of managerial challenges employees experience regarding organisational justice in hospitals. DESIGN/METHODOLOGY/APPROACH: This exploratory study of 8,971 employees working in 14 hospitals and examines the concept of organisational justice in management with qualitative and quantitative methods. FINDINGS: An inductive content analysis of the comments revealed five integrative frames describing challenges in hospital management at respondents' workplaces. These frames should be regarded as major managerial challenges in hospitals. These findings illustrate important antecedents of organisational justice and suggest that work units tend to share the same perceptions of justice. They also reveal that individually produced comments reflect collective experiences in organisational justice. Further, the results indicate that problems in management and policies are often experienced in a complex way, and people making justice judgements do not separate procedural and interactional factors. RESEARCH LIMITATIONS/IMPLICATIONS: Although the commentators producing qualitative data represented many organisational hierarchy levels, the results should not be generalised to apply to horizontal, informal social relationships. PRACTICAL IMPLICATIONS: This paper gives useful information regarding challenges in human resources management in hospitals. ORIGINALITY/VALUE: The paper suggests that people making fairness judgements do not make a distinction between procedural and interpersonal factors. Instead, they use any information available to judge the righteousness of the management events. This paper serves to guide hospital managers towards a better understanding of the importance of organisational justice and its collective nature.  相似文献   
130.
Low-trauma fractures of elderly people are a major public health burden worldwide, and as the number and mean age of older adults in the population continue to increase, the number of fractures is also likely to increase. Epidemiologically, however, an additional concern is that, for unknown reasons, the age-standardized incidence (average individual risk) of fracture has also risen in many populations during the recent decades. Possible reasons for this rise include a birth cohort effect, deterioration in the average bone strength by time, and increased average risk of (serious) falls. Literature provides evidence that the rise is not due to a birth cohort effect, whereas no study shows whether bone fragility has increased during this relatively short period of time. This osteoporosis hypothesis could, however, be tested if researchers would now repeat the population measurements of bone mass and density that were made in the late 1980s and the 1990s. If such studies proved that women's and men's age-standardized mean values of bone mass and density have declined over time, the osteoporosis hypothesis would receive scientific support. The third explanation is based on the hypothesis that the number and/or severity of falls has risen in elderly populations during the recent decades. Although no study has directly tested this hypothesis, a great deal of indirect epidemiologic evidence supports this contention. For example, the age-standardized incidence of fall-induced severe head injuries, bruises and contusions, and joint distortions and dislocations has increased among elderly people similarly to the low-trauma fractures. The fall hypothesis could also be tested in the coming years because the 1990s saw many research teams reporting age- and sex-specific incidences of falling for elderly populations, and the same could be done now to provide data comparing the current incidence rates of falls with the earlier ones.  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