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   4944篇
  免费   419篇
  国内免费   18篇
耳鼻咽喉   31篇
儿科学   223篇
妇产科学   152篇
基础医学   692篇
口腔科学   92篇
临床医学   628篇
内科学   997篇
皮肤病学   83篇
神经病学   283篇
特种医学   163篇
外科学   600篇
综合类   90篇
一般理论   8篇
预防医学   606篇
眼科学   82篇
药学   408篇
中国医学   3篇
肿瘤学   240篇
  2022年   41篇
  2021年   84篇
  2020年   59篇
  2019年   85篇
  2018年   124篇
  2017年   76篇
  2016年   97篇
  2015年   106篇
  2014年   165篇
  2013年   216篇
  2012年   290篇
  2011年   303篇
  2010年   205篇
  2009年   170篇
  2008年   294篇
  2007年   282篇
  2006年   284篇
  2005年   312篇
  2004年   266篇
  2003年   259篇
  2002年   220篇
  2001年   94篇
  2000年   96篇
  1999年   106篇
  1998年   50篇
  1997年   37篇
  1996年   49篇
  1995年   50篇
  1994年   21篇
  1993年   27篇
  1992年   66篇
  1991年   67篇
  1990年   50篇
  1989年   70篇
  1988年   54篇
  1987年   42篇
  1986年   54篇
  1985年   46篇
  1984年   30篇
  1983年   30篇
  1981年   23篇
  1980年   20篇
  1979年   23篇
  1978年   19篇
  1976年   17篇
  1974年   19篇
  1973年   20篇
  1972年   18篇
  1970年   26篇
  1966年   23篇
排序方式: 共有5381条查询结果,搜索用时 0 毫秒
11.
The aim of this study was to determine if DNA polymorphism within runt-related gene 2 (RUNX2)/core binding factor A1 (CBFA1) is related to bone mineral density (BMD). RUNX2 contains a glutamine-alanine repeat where mutations causing cleidocranial dysplasia (CCD) have been observed. Two common variants were detected within the alanine repeat: an 18-bp deletion and a synonymous alanine codon polymorphism with alleles GCA and GCG (noted as A and G alleles, respectively). In addition, rare mutations that may be related to low BMD were observed within the glutamine repeat. In 495 randomly selected women of the Geelong Osteoporosis Study (GOS), the A allele was associated with higher BMD at all sites tested. The effect was maximal at the ultradistal (UD) radius (p = 0.001). In a separate fracture study, the A allele was significantly protective against Colles' fracture in elderly women but not spine and hip fracture. The A allele was associated with increased BMD and was protective against a common form of osteoporotic fracture, suggesting that RUNX2 variants may be related to genetic effects on BMD and osteoporosis.  相似文献   
12.
13.
A 41-year-old woman with active, seropositive erosive rheumatoid arthritis was treated with the humanized monoclonal antibody Campath 1H. She had not responded or developed side effects to myocrisin, sulfasalazine and penicillamine, and had not responded to inpatient bedrest and physiotherapy. There was a rapid clinical improvement within 24 hours of infusion, which was maintained for about 12-14 weeks after the infusion. The lymphocyte count was suppressed for 7 months after treatment. There were no significant side effects during or after treatment. No anti-Campath 1H response was detected. This preliminary study suggests humanized monoclonal antibody therapy may be of value in the treatment of rheumatoid arthritis.  相似文献   
14.
Summary: We report a series of 8 patients with ictal déjà vu. Subdural strip electrocorticographic (ECoG) monitoring localized the ictal epileptogenic focus as follows: right (n = 6) and left (n = 2) mesiotemporal lobe. In all 8 patients, the left hemisphere was dominant for language function based on intracarotid amytal testing. In 6 right-handed patients, ictal déjà vu was associated with a right temporal lobe focus. However, in the 2 left-handed patients, the ictal focus was left temporal lobe. Although ictal déjà vu localizes the epileptic focus to temporal lobe, this experiential phenomenon appears to lateralize to the hemisphere nondominant for handedness.  相似文献   
15.
We investigated the effects of activated protein C resistance (APCR), Factor V Leiden (FVL) mutation, and high lipoprotein (a) levels in 32 young patients with branch retinal vein occlusion (BRVO) vs 30 controls. No difference between patients with BRVO and controls was found with regard to APCR, FVL mutation, or lipoprotein (a) levels. These factors do not seem important in the etiology of BRVO. The authors have stated that they do not have a significant financial interest or other relationship with any product manufacturer or provider of services discussed in this article. The authors also do not discuss the use of off-label products, which includes unlabeled, unapproved, or investigative products or devices.  相似文献   
16.
Abstract: Ambient air was monitored for pesticides at four sites in Coffs Harbour, a coastal town (population about 50 000) surrounded by banana plantations. Air was sampled continuously for five consecutive months during the peak agricultural spraying period using vacuum pumps set to sample one litre per minute through ORBO-42 adsorption tubes. Six pesticides were detected: three organochlorines and three organophosphates. The most commonly detected pesticide (14 per cent of all samples) was chlor-pyrifos (maximum detected level 208.0 ng/m3, mean 3.6 ng/m3). Heptachlor was detected in 7.1 per cent of all samples (maximum detected level 133 ng/m3, mean 2.7 ng/m3). Other pesticides were only rarely detected. The only pesticide applied by air in the district (propiconazole) was not detected. If international health guidelines are used as a yardstick, these levels of exposure appear unlikely to present an appreciable health risk. Chlorpyrifos detection was associated with low wind speed (P = 0.012) and high temperature (P = 0.015), and detection at one site was associated with detection at another (P < 0.001). Chlorpyrifos detection was also associated with domestic applications within the town area as reported by pesticide applicators (P = 0.045). Peak agricultural use of chlorpyrifos did not coincide with peak detection periods. None of the detected organochlorines is registered for agricultural use, although at the time, heptachlor was permitted for use as a domestic termiticide. Even in a semirural town with nearby widespread use of agricultural chemicals, community exposures to pesticides in ambient air may largely relate to their nonagricultural use.  相似文献   
17.
Mini-Mental State Examination (MMSE) scores were studied in an ambulatory elderly population to identify correlates with self-reported signs, symptoms, diseases, drugs and laboratory values. A total of 1,264 subjects were studied including 844 women and 420 men. In this study, 5.0% of men and 5.3% of women scored less than 24 on the MMSE. A linear-regression model revealed eleven factors of significance in predicting scores on the MMSE. The most important predictors were age (p less than 0.0001), self-reported memory loss (p less than 0.0001), complaints of swollen feet or ankles (p less than 0.0010), the total number of diseases reported (0.0006) and the serum lactate dehydrogenase concentration (p less than 0.0098). Results suggest that cognitive function in the elderly is not related to the general level of health or consistently affected by specific disease states.  相似文献   
18.
19.
PURPOSE: To describe a patient diagnosed with pheochromocytoma in the third trimester of pregnancy and discuss the perioperative and anesthetic management. CLINICAL FEATURES: A 32-yr-old previously healthy woman (gravida 4, para 2) presented to our tertiary care obstetrical hospital at 34 weeks five days gestation with a history of labile blood pressure and severe hypertension. A week prior to admission she began having episodes of severe headache, dizziness, sweating and nausea. On a routine obstetric visit she was noted to be severely hypertensive with a blood pressure of 200/120 mmHg. Biochemical investigations confirmed the diagnosis of pheochromocytoma and magnetic resonance imaging demonstrated a 3 cm x 3 cm right adrenal mass. The patient was invasively monitored in the intensive care unit and treated with alpha- followed by beta-blockade with phenoxybenzamine and metoprolol. A multidisciplinary conference was organized involving endocrinology, anesthesiology, general surgery and obstetrics to determine the most appropriate management of the patient. An uncomplicated laparoscopic adrenalectomy was performed following a period of recovery after an uneventful elective Cesarean delivery. CONCLUSIONS: The primary goals in the management of pheochromocytoma in pregnancy are early diagnosis, avoidance of a hypertensive crisis during delivery and definitive surgical treatment. Timing of surgical resection will depend on the gestational age at which diagnosis is made. Cesarean section is the preferred mode of delivery when the tumour is still present. This case illustrates that with antenatal diagnosis, advanced methods of tumour localization, adequate preoperative adrenergic blockade and team planning, pheochromocytoma in pregnancy can be treated successfully.  相似文献   
20.
AIMS: To study the pattern of expression and prognostic importance of c-erbB-2 protein in cervical carcinoma. METHODS: Sixty two cases of stage IB/IIA cervical carcinoma, representing the three main tumour types, were investigated immunohistochemically for the presence of c-erbB-2 protein expression, using a monoclonal antibody (CB11) to its internal domain. Follow up of at least five years' duration was available in all cases. RESULTS: Definite membrane staining was seen in 38.7% of cases. There was a strong correlation with poor survival (p less than 0.0001) particularly. For those with adenocarcinomas, this was the case when nodal metastases were present. In contrast, for squamous carcinomas and adenosquamous carcinomas, the association with a poor prognosis was most apparent in those patients without lymph node metastases. CONCLUSIONS: These findings raise the possibility that immunostaining for c-erbB-2 protein could be used as a prognostic marker and may help identify those patients for whom early adjuvant treatment might be beneficial.  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