首页 | 官方网站   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   1267篇
  免费   117篇
医药卫生   1384篇
  2021年   13篇
  2019年   20篇
  2018年   13篇
  2016年   13篇
  2015年   15篇
  2014年   17篇
  2013年   33篇
  2012年   47篇
  2011年   48篇
  2010年   20篇
  2009年   17篇
  2008年   57篇
  2007年   50篇
  2006年   56篇
  2005年   39篇
  2004年   52篇
  2003年   46篇
  2002年   45篇
  2001年   39篇
  2000年   55篇
  1999年   36篇
  1998年   13篇
  1997年   16篇
  1996年   12篇
  1995年   13篇
  1994年   10篇
  1993年   13篇
  1992年   45篇
  1991年   49篇
  1990年   39篇
  1989年   42篇
  1988年   40篇
  1987年   36篇
  1986年   36篇
  1985年   33篇
  1984年   27篇
  1983年   18篇
  1982年   18篇
  1981年   18篇
  1979年   16篇
  1978年   15篇
  1977年   8篇
  1976年   12篇
  1975年   11篇
  1974年   14篇
  1973年   14篇
  1971年   7篇
  1969年   7篇
  1968年   11篇
  1967年   11篇
排序方式: 共有1384条查询结果,搜索用时 31 毫秒
1.
2.
This study examined the immunoregulatory role of recombinant interleukin 4 (IL-4), also known as B-cell stimulating factor 1, on the generation of cytotoxic effector cells from normal and leukaemic human blood mononuclear cells. When tested on cells from normal individuals, the addition of IL-4 to mixed lymphocyte cultures led to a dose-dependent proliferation of T-helper cells (CD3, 4 positive) with a concomitant decrease in phenotypic and functional cytotoxic T cells and natural killer (NK) cells. IL-4 also inhibited the interleukin-2 (IL-2)-induced generation of lymphokine-activated killer (LAK) activity when added at the beginning of mixed lymphocyte culture. When tested on mature leukaemic NK cells, IL-4 also inhibited the ability of IL-2 to induce LAK function using a short-term culture system. These results show that IL-4 acts on both normal and leukaemic cells and suggests that it acts at more than one level during the development of LAK function.  相似文献   
3.
A digital test of pelvic muscle strength for evaluation of a pelvic muscle exercise (PME) program was developed with a sample of 338 incontinent women living at home. Factors of perceived pressure, alteration of the vertical plane, and time were combined to form a 7-point scale ranging from 0 to 4. Test-retest for the anteroposterior score was r = .65, p less than .01 with interrater reliability, r = .91, p less than .01. Relationship to other variables and further development of the measure are discussed.  相似文献   
4.
A significant number of nursing home residents exhibit behavior disturbances that are disruptive to the living and working environment in the nursing home. The most common disruptive behaviors cited by licensed nursing personnel included hitting/slapping, verbally aggressive remarks, screaming, pacing, wandering, and repetitive verbal requests. Self-injurious behavior, property destruction, and hiding things were not mentioned. Many of the nursing strategies listed by nursing staff as being used to alleviate disruptive behaviors are traditional care activities, eg, talking to and counseling patients, touching, or altering care. However, chemical and physical restraints were also frequently listed.  相似文献   
5.
AIM: To determine whether axillary recurrence reflects inadequate axillary treatment or adverse pathological features. METHODS: The case-records were reviewed of 2122 women aged under 75 years, treated for invasive breast cancer during the time-period 1/1/86-31/12/91 in a geographically defined area. Data were abstracted on operations performed, pathological features, post-operative treatments and details of axillary recurrence. The risk of axillary recurrence was examined by pathological, treatment and patient factors. RESULTS: Axillary recurrence was more than twice as likely after inadequate compared to adequate treatment of the axilla (adequate staging or axillary radiotherapy or clearance). Delayed treatment of the axilla was not as successful as adequate primary treatment: multiple axillary recurrences were twice as common, one third of which were uncontrolled at time of death. Inadequate surgical treatment was associated with increased rates of recurrence despite endocrine therapy, chemotherapy or radiotherapy. Lymphoedema was twice as common if axillary radiotherapy was combined with any axillary surgical procedure. CONCLUSIONS: Axillary recurrence is more common in tumours with adverse pathology but may also result from inadequate axillary treatment. In order to minimise axillary recurrence, optimal treatment of the axilla entails adequate staging (sampling of four or more nodes) and treatment (axillary clearance or radiotherapy and endocrine therapy) in all women.  相似文献   
6.
The kinetics of antibody responses of Mycobacterium leprae-infected armadillos to phenolic glycolipid-I (PGL-I) were studied by means of ELISA. The levels of both IgG and IgM antibodies to PGL-I increased with time. Some animals were less susceptible to disseminations of M. leprae infection and lived longer than others. These animals had high absorbance values (greater than 0.7) for IgG anti-PGL-I compared to more susceptible armadillos that had lower absorbance values for IgG anti-PGL-I.  相似文献   
7.
Endothelin-like immunoreactivity was observed in the endothelial lining of umbilical vein and artery as well as in the epithelium of the amniotic membrane. High levels of endothelin-like immunoreactivity (0.4-1.4 pmol g-1) were detected in human amniotic membrane, umbilical vessels and placenta. The concentration of endothelin-like immunoreactivity in the amniotic fluid was much higher (77 pmol l-1) than in umbilical cord plasma (10 pmol l-1). Characterization by reverse phase HPLC revealed that most of the endothelin-like immunoreactivity eluted in the position of synthetic endothelin-1 or oxidized endothelin-1. Specific, high affinity binding sites for endothelin-1 were present in placenta and umbilical artery. Endothelin binding sites were also found in cultured smooth muscle cells from the umbilical artery and vein. In the placenta, endothelin-1 and -3 were almost equipotent as competing ligands for endothelin-1 binding sites, whereas in the umbilical artery endothelin-3 was much less potent than endothelin-1. Scatchard analysis of the binding for placental membranes displayed a straight line (r = -0.994) indicating a single class of endothelin receptors with a Kd-value of 80 pmol l-1 and Bmax of 113 fmol mg-1. Endothelin-1 caused potent contractions of umbilical arteries and veins with threshold effects at 10 pmol l-1 while endothelin-3 had no contractile effect up to 10(-7) mol l-1. It is concluded that endothelin-1 predominates over other endothelins in umbilical vessels, amnion and placenta, and high levels of endothelin-1 was observed in foetal circulation and amniotic fluid. Endothelin-receptors seem to be of different types in placenta (ETB type) and umbilical vessels (ETA type).  相似文献   
8.
Fast skeletal muscles of mdx (X chromosome-linked muscular dystrophy) mice were injected after birth with a recombinant adenovirus containing a minidys- trophin gene, a 6.3-kbp cDNA coding for the N- and C-terminal ends of dystrophin. Adult muscles were challenged by forced lengthening during tetanic contractions. Stretch-induced mechanical and histological damages were much reduced in injected muscles, in direct proportion of the Miniber of fibers expressing minidystrophin. Damaged fibers were preferentially found among minidystrophin-negative regions. Minidystrostrophin confers an important functional and structural protection of limb muscles against high mechanical stress, even after a partial somatic gene transfer.  相似文献   
9.
The purpose of our study was to determine whether clonidine exerts its centrally mediated hypotensive action at three sites that influence arterial pressure located in the medulla, specifically associated with the intermediate area of the ventrolateral medulla. The "intermediate area" lies approximately 1.5 mm caudal to the border of the trapezoid body (caudal border) and 4 mm lateral to the midline. One of the sites that influence arterial pressure lies in the nucleus reticularis rostroventrolateralis. The second site lies in close proximity to the rostral part of the nucleus reticularis lateralis (rLRN) and also near the A1 area. The third site lies in the most rostral area and medial to the nucleus reticularis rostroventrolateralis, that is in the nucleus paragigantocellularis lateralis. Unilateral microinjections of 0.22 and 0.43 nmol of clonidine into the rLRN produced dose-dependent decreases in arterial pressure. The 0.43 nmol dose of clonidine had no effect when unilaterally or bilaterally microinjected into either the nucleus reticularis rostroventrolateralis or into the nucleus paragigantocellularis lateralis. Microinjection of the alpha-2 adrenoceptor antagonist, idazoxan (16.6 nmol), unilaterally into rLRN had no effect per se, but prevented the hypotensive effect of a subsequent microinjection of clonidine. Similarly, bilateral microinjection of idazoxan into rLRN counteracted the hypotensive effect of i.v. administered clonidine. These data indicate that clonidine acts at alpha-2 adrenoceptors in the rLRN to produce hypotension.  相似文献   
10.
We report on a child with giant congenital aortic aneurysm, sternal defect, hemangiomas of face, supraumbilical raphé, and review the only two other cases reported to date. Congenital aortic aneurysm is an ominous malformation that has to be systematically searched in children with the sternal malformation/vascular dysplasia complex.  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-23

京公网安备 11010802026262号