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   2943135篇
  免费   233762篇
  国内免费   5884篇
耳鼻咽喉   42608篇
儿科学   91410篇
妇产科学   80729篇
基础医学   414459篇
口腔科学   84213篇
临床医学   264505篇
内科学   577828篇
皮肤病学   60478篇
神经病学   245552篇
特种医学   117898篇
外国民族医学   1129篇
外科学   449742篇
综合类   68601篇
现状与发展   1篇
一般理论   1171篇
预防医学   233943篇
眼科学   69305篇
药学   218724篇
  4篇
中国医学   5550篇
肿瘤学   154931篇
  2018年   30016篇
  2016年   25541篇
  2015年   28882篇
  2014年   41626篇
  2013年   63589篇
  2012年   85623篇
  2011年   90462篇
  2010年   53658篇
  2009年   51492篇
  2008年   86171篇
  2007年   91520篇
  2006年   92403篇
  2005年   90209篇
  2004年   86678篇
  2003年   83837篇
  2002年   82655篇
  2001年   135294篇
  2000年   139648篇
  1999年   118330篇
  1998年   34137篇
  1997年   31116篇
  1996年   30861篇
  1995年   29645篇
  1994年   27837篇
  1993年   26066篇
  1992年   94906篇
  1991年   91582篇
  1990年   88595篇
  1989年   85388篇
  1988年   79433篇
  1987年   78176篇
  1986年   74399篇
  1985年   70931篇
  1984年   53646篇
  1983年   45772篇
  1982年   27974篇
  1981年   24763篇
  1980年   23324篇
  1979年   50285篇
  1978年   35269篇
  1977年   29886篇
  1976年   28048篇
  1975年   29797篇
  1974年   36505篇
  1973年   34735篇
  1972年   32631篇
  1971年   30161篇
  1970年   28538篇
  1969年   26631篇
  1968年   24559篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
In a randomised, double-blind study, 20 women with idiopathic detrusor instability and associated symptoms were treated with terodiline 25 mg bd, placebo, and emepronium bromide 200 mg tds--each drug being given for 3 weeks with placebo as wash-out period before cross-over. The results were evaluated according to drug preference, frequency charts and elimination of detrusor instability on cystometry. Serum levels of both drugs were monitored as control of tablet intake. The preference for terodiline to placebo was statistically significant: 14/3 women (P less than 0.05), and the majority of women (12/4) preferred terodiline to emepronium. Terodiline also gave a small but significant reduction in 24 h micturition frequency and eliminated detrusor instability in almost 50% of the patients (P less than 0.05). Side effects were frequent but mild in all three treatment periods. It was concluded that terodiline offers an alternative in the treatment of female detrusor instability.  相似文献   
962.
Multiple trauma is often associated with blunt thoracic injuries. Especially lung contusion can result in respiratory insufficiency and therefore a higher mortality rate. In our prospective study comparing 8 multiple trauma patients with and without associated lung contusion, we found that respiratory function was already significantly disturbed (decrease of paO2/FiO2 and increase of AaDO2, a rise in extravascular lung water (EVLW) both early after trauma and also with a second peak following the 4th day. This group (LK) developed significantly more cases of respiratory distress (ARDS). The disturbance of respiratory function seen initially was interpreted as a consequence of the direct mechanical impact, leading to the formation of interstitial fluid and hematoma. The frequent development of ARDS in the LK-group probably results from a pronounced activation of cellular and humoral mechanisms and therefore an enforced injury of the pulmonary capillary bed. A significant increase of pulmonary infections or the development of sepsis was not seen in the LK-group and is probably not responsible for the higher ARDS-rate in this group.  相似文献   
963.
The skeletal manifestations of malignant carcinoid seem not to have been reported in the orthopedic literature. Bronchial and hindgut carcinoid tumors are less numerous than midgut tumors but metastasize to bone much more frequently. Carcinoid skeletal deposits are usually osteoblastic and most commonly affect the axial skeleton. The radiologic appearance is frequently indistinguishable from prostatic skeletal metastases or chronic sclerosing osteomyelitis. Two cases of skeletal metastases from midgut carcinoid are reported to demonstrate that metastases from carcinoid should be considered in the differential diagnosis of either bone malignancy or chronic sclerosing osteomyelitis.  相似文献   
964.
The influence of the pore size of Nucleopore diffusion-chamber filters on the rate of proliferation and differentiation of periosteal cells in muscle was studied in 44 growing rabbits. Periosteal grafts were placed in chambers (16-19 in each experimental group) sealed with filters with a pore size of 0.4, 0.6, 0.8, 1.0, or 2.0 micron. Each chamber was implanted into the paraspinal muscle of the rabbit, where it remained for 16 weeks. The osteochondrogenic activity of the graft grew linearly when the pore size increased from 0.4 to 1.0 micron. In the chambers with a pore size of 2.0 micron, both bone and cartilage were found in only one chamber. Bone and cartilage were not found outside any of the chambers. The present results showed that the pore size of the filters significantly affected the ability of the periosteal graft to form bone and cartilage.  相似文献   
965.
The effects of bulk versus particulate polymethylmethacrylate on bone   总被引:3,自引:0,他引:3  
Twenty-one mature New Zealand white female rabbits were allocated into three groups of seven rabbits. Group I received a bolus of doughy Simplex polymethylmethacrylate (PMMA) cement injected into the proximal tibia through a drill hole. Group II received a preformed, cooled, bulk PMMA pellet. Group III had particulate PMMA powder implanted. The operated, but nonimplanted, left tibiae served as controls. Animals were killed after four months. Histologically, both Group I and Group II demonstrated a thin, fibrous tissue membrane at the implant interface. Particulate PMMA (Group III) stimulated a much thicker, florid, foreign body reaction composed of histiocytes and giant cells. The foreign body response to particulate acrylic cement was similar to that seen in failed cemented joint replacement arthroplasty in humans.  相似文献   
966.
Computed tomography (CT) is currently the imaging modality of choice for assessing the morphology of the adrenal glands in adult patients. Much useful information can be gained using CT in disease processes which primarily involve one or both of the adrenal glands, such as adenomas, as well as in entities which secondarily affect the adrenals, such as pituitary or metastatic disease. The size and configuration of the glands can be readily determined, and masses may be detected. We discuss CT of normal and abnormal adrenal glands with sonographic (US) and pathological correlation, when available. Entities which may mimic adrenal abnormalities are emphasized. Relative advantages of US over CT in the pediatric patient are discussed.  相似文献   
967.
The impact of recombinant human tumour necrosis factor-alpha (1 microgram kg-1 to 1 mg kg-1; 6.6 x 10(6) U mg protein-1) on blood flow, oxygen consumption and growth of a moderately TNF-sensitive rat tumour (DS-carcinosarcoma) was studied. Tumour growth was stimulated at low TNF doses (1 and 10 micrograms kg-1) and significantly retarded at higher TNF dose levels (0.1 and 1 mg kg-1). Growth changes were concomitant with variations in oxygen consumption, lactate release and acidification of the metabolic micromilieu. Both single and repeated application of low TNF doses (1-10 micrograms kg-1 i.v.) increased tumour perfusion whereas single administration of high TNF dose levels (0.1-1 mg kg-1 i.v.) reduced tumour blood flow. After repeated application of high TNF doses tumours shrank to such small sizes that perfusion measurements could not be performed within the observation period of two weeks. It is concluded that TNF effects on solid tumours are at least partially mediated by changes in tumour perfusion. Thus, an altered tumour sensitivity towards other treatment modalities, e.g. irradiation, chemotherapy or hyperthermia, can be expected after TNF therapy. A beneficial TNF effect would critically depend on the dose level employed and on the sequence and timing of various combination regimes.  相似文献   
968.
969.
J Arton 《Nursing times》1988,84(14):96-98
  相似文献   
970.
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