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   20255篇
  免费   1383篇
  国内免费   97篇
耳鼻咽喉   186篇
儿科学   448篇
妇产科学   365篇
基础医学   2698篇
口腔科学   221篇
临床医学   1936篇
内科学   4582篇
皮肤病学   324篇
神经病学   2077篇
特种医学   946篇
外科学   3395篇
综合类   133篇
一般理论   6篇
预防医学   1266篇
眼科学   209篇
药学   1382篇
中国医学   23篇
肿瘤学   1538篇
  2023年   129篇
  2022年   195篇
  2021年   528篇
  2020年   275篇
  2019年   506篇
  2018年   602篇
  2017年   435篇
  2016年   418篇
  2015年   535篇
  2014年   827篇
  2013年   988篇
  2012年   1504篇
  2011年   1541篇
  2010年   904篇
  2009年   835篇
  2008年   1261篇
  2007年   1237篇
  2006年   1220篇
  2005年   1101篇
  2004年   1089篇
  2003年   925篇
  2002年   913篇
  2001年   337篇
  2000年   296篇
  1999年   263篇
  1998年   170篇
  1997年   166篇
  1996年   124篇
  1995年   132篇
  1994年   110篇
  1993年   103篇
  1992年   153篇
  1991年   157篇
  1990年   150篇
  1989年   152篇
  1988年   145篇
  1987年   122篇
  1986年   118篇
  1985年   106篇
  1984年   82篇
  1983年   84篇
  1982年   55篇
  1979年   60篇
  1978年   57篇
  1975年   47篇
  1974年   48篇
  1972年   48篇
  1971年   41篇
  1970年   48篇
  1969年   39篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
M. J. Ball  BSc  MB  BCh  MRCP    J. W. Sear  BSc  PhD  FFARCS  DRCOG   《Anaesthesia》1986,41(4):423-426
Critically ill patients are usually in a catabolic state and may require total parenteral nutrition; this often includes lipid emulsions. Any adverse effects of constituents on pulmonary function, white cell function or the haemocoagulation system could have disastrous consequences in such patients. We have investigated the effects of a new intravenous lipid preparation containing medium chain triglycerides, which, in severely ill malnourished patients are theoretically a preferable energy source to conventional drug chain triglycerides. In a pilot study 17 critically ill patients whose lungs were artificially ventilated were given this lipid emulsion; no adverse effects were observed. Arterial oxygen and carbon dioxide tensions, ratio of inspired oxygen fractional concentration to arterial oxygen tension, platelet and white cell counts all remained constant and the complement system was not activated.  相似文献   
62.
The purpose of this study was to determine if cephaloridine nephrotoxicity is attenuated in streptozotocin (STZ)-induced diabetic rats. Fischer 344 (F344) rats (205-250 g) were given a single injection (i.p.) of STZ (27-35 mg/kg) or citrate buffer. The nephrotoxicity of (750 mg/kg) cephaloridine (i.p.) was then compared with normoglycemic and 14-day diabetic rats. Increased blood urea nitrogen (BUN) levels as well as diminished renal cortical slice accumulation of tetraethylammonium (TEA) and lactate-stimulated p-aminohippurate (PAH) were measured (P less than 0.05) in normoglycemic rats 48 h after cephaloridine administration. Cephaloridine failed to alter BUN levels and organic ion accumulation in diabetic rats. Diabetes did not totally protect against cephaloridine toxicity since kidney weights were elevated in normoglycemic and diabetic rats 48 h after administration of 750 mg/kg cephaloridine. A series of experiments also measured BUN levels, kidney weight and renal cortical slice uptake of PAH and TEA 24, 48 and 72 h after (1500 mg/kg) cephaloridine administration. Cephaloridine increased (P less than 0.05) kidney wt and decreased PAH and TEA uptake (P less than 0.05) in the normoglycemic group at 24-72 h. No change in kidney wt, PAH or TEA uptake was observed in the diabetic rats. These data indicate diabetes reduces cephaloridine nephrotoxicity.  相似文献   
63.
PURPOSE: To examine changes in health habits (sleep, alcohol, and exercise) and the effects of an educational intervention promoting self-care on the emotional and academic adjustment of first-year medical students. METHOD: Fifty-four medical students completed questionnaires that assessed various health habits, alcohol use, depression severity, and areas of life satisfaction at the beginning of the semester, at mid-term, and at finals. Approximately half of the students received written feedback or participated in an educational discussion group at mid-term. RESULTS: The students demonstrated significant changes in health habits, with increases in alcohol consumption and decreases in exercise and socialization. The changes in health habits were predictive of both emotional and academic adjustment, with students who decreased in positive health habits, particularly socialization, being more depressed at finals. The feedback and educational interventions influenced some sleep and exercise behaviors, but the groups did not differ in overall emotional or academic adjustment. CONCLUSIONS: First-year medical students show significant changes in health habits as they adjust to medical school. An educational intervention demonstrated promising effects in changing these patterns, but self-care needs to be further elaborated to address the specific challenges associated with acute adjustment as well as with long-term stressors.  相似文献   
64.
Sir, We read with interest the recent article by Buzello et al. [1]on renal changes in apo E-/- mice after subtotal nephrectomy.They compared renal lesion development in male wild-type C57BL/6mice with that of genetically modified male apo E-/- mice aftereither sham operation, unilateral nephrectomy or subtotal nephrectomy(SNX) by removal of 75% of the cortex in one kidney and removalof the contralateral kidney. They found  相似文献   
65.
OBJECTIVE: To assess the extent of nosocomial transmission of tuberculosis among infants, family members, and healthcare workers (HCWs) who were exposed to a 29-week-old premature infant with congenital tuberculosis, diagnosed at 102 days of age. DESIGN: A prospective exposure investigation using tuberculin skin test (IST conversion was conducted. Contacts underwent two skin tests 10 to 12 weeks apart. Clinical examination and chest radiographs were performed to rule out disease. Isoniazid prophylaxis was administered to exposed infants at higher risk. SETTING: A neonatal intensive care unit in an urban hospital in Brussels, Belgium. PARTICIPANTS: Ninety-seven infants, 139 HCWs, and 180 visitors. RESULTS: Newly positive TST results occurred in HCWs who had been in close contact with the infant. Six (19%) of 32 primary care nurses and physicians had TST conversions and received treatment. Among the 97 exposed infants, 85 were screened and 34 were identified as at higher risk of infection. Of these, 27 received preventive isoniazid. None of the infants and none of the 93 other infants' family members evaluated were infected. CONCLUSIONS: Congenital tuberculosis in an infant poses a risk for nosocomial transmission to HCWs. Delayed diagnosis of this rare disease and close proximity are the most important factors related to transmission.  相似文献   
66.
The mucus producing colonic cell line, LS174T, was used as a model to study E. histolytica-induced mucin secretion. E. histolytica trophozoites in contact with the mucus layer overlying the LS174T cells and in response to PMA, a protein kinase C activator, and Ca2+ ionophore A23187 which elevates intracellular Ca2+ ([Ca]i), caused a time-dependent (0.25-2.00 h) release of mucin. PKC inhibitors, H7 and staurosporine inhibited E. histolytica (37 and 75%) and PMA (46 and 100%)-induced mucin secretion, whereas in response to Ca2+ ionophore mucin secretion was augmented (56 and 17%). Both PMA and E. histolytica-induced the translocation of the PKC enzyme from the cytoplasm to the membrane fraction with increased enzyme activity. These results suggest that even though mucin secretion can be induced by PKC and Ca(2+)-dependent pathways, E. histolytica evokes the fast release of mucins by a PKC-dependent mechanism.  相似文献   
67.
EEG in borderline personality disorder   总被引:1,自引:0,他引:1  
  相似文献   
68.
Summary: It is not generally appreciated that intractable seizures involving the face area are amenable to surgical treatment. Twenty patients with onset of sensorimotor seizures in the face area of the pre- and postcentral gyri have been studied and surgically treated since 1948. Seizures started in the face, tongue, or throat, followed by diverse patterns depending on spread of seizure activity. Two patients had epilepsia partialis continua; 6 had either tonic or atonic drop attacks. All patients had pre- and postcentral face area resections, 12 in the dominant hemisphere. In addition, 3 had more extensive postcentral removal, 7 had temporal lobe, and 4 had small separate or contiguous frontal or parietal resection. Because the seizures were not sufficiently reduced by the first operation, 6 required reoperation; 4 of these patients had residual epileptiform activity on electrocorticogram (ECoG) after the first resection. Three patients had new neurologic signs that did not return to the preoperative level, but in 2 of them the deficit related mainly to higher resection in the central area. All but 2 of these 20 patients had at least moderate seizure reduction. Corticectomy can be performed for treatment of seizures arising in the lower central area and usually does not lead to significant permanent neurologic deficit.  相似文献   
69.
70.
Anomalously low affinities for the beta-1-adrenoceptor are seen for members of a series of para-substituted N-isopropylphenoxypropanolamines in which the substituent is able to conjugate with the aromatic ring. The energy of conjugation was calculated using the AM1 semiempirical molecular orbital method and appears to correlate with the loss of binding energy, and hence affinity for the receptor. This suggests that binding is associated with movement of the substituent out of the plane of the aromatic ring due to steric interference with the receptor. A previously unrecognized binding site for aromatic groups off the para position is also identified.  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