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   7468篇
  免费   303篇
  国内免费   35篇
耳鼻咽喉   26篇
儿科学   115篇
妇产科学   88篇
基础医学   790篇
口腔科学   151篇
临床医学   491篇
内科学   1920篇
皮肤病学   75篇
神经病学   592篇
特种医学   347篇
外科学   1270篇
综合类   37篇
预防医学   152篇
眼科学   454篇
药学   430篇
中国医学   12篇
肿瘤学   856篇
  2022年   56篇
  2021年   114篇
  2020年   56篇
  2019年   93篇
  2018年   107篇
  2017年   101篇
  2016年   146篇
  2015年   123篇
  2014年   176篇
  2013年   190篇
  2012年   327篇
  2011年   320篇
  2010年   203篇
  2009年   169篇
  2008年   293篇
  2007年   308篇
  2006年   331篇
  2005年   309篇
  2004年   329篇
  2003年   312篇
  2002年   352篇
  2001年   298篇
  2000年   326篇
  1999年   268篇
  1998年   88篇
  1997年   81篇
  1996年   66篇
  1995年   64篇
  1994年   63篇
  1993年   54篇
  1992年   194篇
  1991年   168篇
  1990年   151篇
  1989年   167篇
  1988年   156篇
  1987年   101篇
  1986年   136篇
  1985年   123篇
  1984年   78篇
  1983年   75篇
  1979年   74篇
  1978年   44篇
  1977年   46篇
  1974年   46篇
  1973年   49篇
  1972年   46篇
  1971年   58篇
  1970年   38篇
  1969年   41篇
  1968年   45篇
排序方式: 共有7806条查询结果,搜索用时 0 毫秒
71.
BackgroundCurved periacetabular osteotomy (CPO) is performed via an anterior approach without detachment of the hip abductor muscles. This study aimed to evaluate the abductor muscle status shortly after CPO on magnetic resonance imaging (MRI).MethodsWe prospectively evaluated 38 hips in 38 patients 1 week and 3 months after CPO between October 2017 and July 2019. The status of the abductor muscles was assessed on MRI using the following criteria: grade 0, normal; grade I, strain/edema; grade II, partial tear; and grade III, complete tear. We also evaluated associations between muscle status and patients’ characteristics.ResultsOne week after CPO, the gluteus maximus was classified as grade 0 in all patients. The gluteus medius was grade 0 in 84.2% of patients and grade I in 15.8%. The gluteus minimus was grade I in 55.3% of patients and grade II in 44.7%. Three months after CPO, both the gluteus maximus and gluteus medius were grade 0 in all patients, while the gluteus minimus was still grade I in 47.4%. There were no significant differences between patients with a grade 0 and grade I gluteus minimus at 3 months after CPO in patients’ characteristics (age and body mass index) or clinical scores (Harris Hip Score and Japanese Orthopedics Association score).ConclusionBoth the gluteus minimus and medius showed abnormal appearances on MRI 1 week after CPO, whereas only the gluteus minimus showed abnormalities 3 months after CPO. This abductor muscle status did not affect the postoperative Harris Hip Score or Japanese Orthopedics Association score.  相似文献   
72.
BackgroundExtrahepatic recurrence and early intrahepatic recurrence of hepatocellular carcinoma after hepatic resection are indicative of poor prognoses. We aimed to develop nomograms to predict extrahepatic recurrence and early intrahepatic recurrence after hepatic resection.MethodsThe participants of this study were 1,206 patients who underwent initial and curative hepatic resection for hepatocellular carcinoma. Multivariate logistic regression analyses using the Akaike information criterion were used to construct nomograms to predict extrahepatic recurrence and early intrahepatic recurrence (within 1 year of surgery) at the first recurrence sites after hepatic resection. Performance of each nomogram was evaluated by calibration plots with bootstrapping.ResultsExtrahepatic recurrence was identified in 95 patients (7.9%) and early intrahepatic recurrence in 296 patients (24.5%). Three predictive factors, α-fetoprotein >200 ng/mL, tumor size (3–5 cm or >5 cm vs ≤3 cm), and image-diagnosed venous invasion by computed tomography, were adopted in the final model of the extrahepatic recurrence nomogram with a concordance index of 0.75. Tumor size and 2 additional predictors (ie, multiple tumors and image-diagnosed portal invasion) were adopted in the final model of the early intrahepatic recurrence nomogram with a concordance index of 0.67. The calibration plots showed good agreement between the nomogram predictions of extrahepatic recurrence and early intrahepatic recurrence and the actual observations of extrahepatic recurrence and early intrahepatic recurrence, respectively.ConclusionWe have developed reliable nomograms to predict extrahepatic recurrence and early intrahepatic recurrence of hepatocellular carcinoma after hepatic resection. These are useful for the diagnostic prediction of extrahepatic recurrence and early intrahepatic recurrence and could guide the surgeon’s selection of treatment strategies for hepatocellular carcinoma patients.  相似文献   
73.
Four monoclonal antibodies against human erythrocyte membrane antigens were established. The antigenic determinants of KOR-E1, E3, E6 were Pr1h antigen, Wrb antigen, and the trypsin sensitive portion of glycophorin A (EnaTS) respectively. The antigen recognized by KOR-E4 could not be determined. The reactivities of these antibodies with normal hematopoietic cells, malignant hematopoietic cell lines (N = 31), and fresh leukemic cells obtained from 128 patients with various types of leukemias were studied. All antibodies reacted only with erythrocytes among peripheral blood cells, and also KOR-E6 reacted only with erythroid cells among bone marrow cells. KOR-E3 had no reactivity with any cell lines examined, and KOR-E1 and KOR-E4 were reactive with some lymphoid cell lines. However, KOR-E6 had specific reactivities with erythroid (HEL, K562), megakaryocytic (CMK-1), multiphenotypic (KOPM-28), and basophilic (KU-812) cell lines. The antigen (glycophorin A) recognized by KOR-E6 was expressed on a small population of mononuclear cells separated from acute lymphoblastic leukemia (3/70), acute myelogenous leukemia (2/12), monosomy 7-myeloproliferative disorder (1/1), juvenile CML (1/1), and transient myeloproliferative disorder with Down's syndrome (4/12), although it could not be determined whether these cells were leukemic cells or not. KOR-E6 was reactive with a large population of leukemic blasts in erythroleukemia (2/2) and acute megakaryoblastic leukemia (3/6). Thus, KOR-E6 appears to be an erythroid marker of leukemic cells.  相似文献   
74.
Seven elderly patients, 79-88 years old, with bladder cancer were treated by transvesical tumorectomy with intraoperative radiation therapy (IORT). The cancers appeared to be of high grade and high stage by cystoscopy and other examinations, and consequently they were diagnosed to be over stage T2. Therefore, all patients were thought to be candidates for total cystectomy. But their ages and complications precluded this treatment, so we decided to carry out the "palliative" IORT. The operation of IORT required less than two hours and required less than 200 ml of blood loss. There were no complications such as hematuria, irritable bladder, and rectal symptoms. The postoperative stage diagnoses coincided with the preoperative ones in 5 cases, but two cases were overdiagnosed. Five patients died after more than one year and 11 months, but four patients died due to other diseases, without cancer. One patient died due to pulmonary cancer confirmed by autopsy. Recurrence was seen in one case. These results confirmed that IORT was effective for local control of bladder cancer and partially prophylactic for recurrence. Furthermore, this treatment seemed to be even curative for some cases. We recommend this modality of treatment for some of aged patients and patients with complications who are unable to undergo cystectomy.  相似文献   
75.
The cardiovascular effects of sevoflurane were studied and compared with those of halothane in 30 healthy patients. The patients were assigned to receive 1MAC sevoflurane (n = 10), 2MAC sevoflurane (n = 10) or 1MAC halothane (n = 10) in N2O 2l·min–1 and O2 4l·min–1. The changes in left ventricular diastolic and systolic dimension (Dd and Ds), fractional shortening (FS), mean velocity of circumferential fiber shortening (mVcf), left ventricular diastolic and systolic volume (Vd and Vs), stroke volume (SV), ejection fraction (EF) and cardiac index (CI) were evaluated by echocardiography. Sevoflurane produced significant dose-dependent decreases in FS, mVcf, EF and SV, but no significant changes in Dd and Vd. Therefore, the decrease in SV was due mainly to the increase in left ventricular residual volume (Vs). One MAC halothane produced a more significant decrease in FS, mVcf, EF and SV, when compared to values obtained at 1MAC sevoflourane (P 0.01). CI was more significantly decreased with 1MAC halothane than with 1MAC and 2MAC sevoflurane (P 0.01). This was brought about by a slight decrease in HR with halothane and a slight increase in HR with sevoflurane, in addition to a smaller decrease in SV with sevoflurane than with halothane. This study suggests that sevoflurane may better preserve cardiac function as a pump in healthy patients, when compared to halothane.(Kasuda H, Akazawa S, Shimizu R.: The echocardiographic assessment of left ventricular performance during sevoflurane and halothane anesthesia. J Anesth 4: 295–302, 1990)  相似文献   
76.
Finger arterial blood pressures determined by a newly developed sphygmomanometer, HEM-802F, were compared with arterial pressure obtained from direct measurement of the radial artery. An excellent correlation was found between the two methods (systolic: r = 0.93, diastolic: r = 0.91), although there was a large variability among individual subjects. The range of differences between them are from +32 to –13mmHg for systolic and +15 to –25mmHg for diastolic blood pressure measurement. HEM-802F underestimated systolic pressure (–4.0mmHg) and overestimated diastolic pressure (+6.7mmHg), compared with intra-arterial readings.The HEM-802F was useful for the non-invasive arterial pressure monitoring during general anesthesia.(Shigemi K, Takahashi H, Hashimoto S et al.: A comparative study of measurement of arterial blood pressure using HEM-802F and arterial cannulation. J Anesth 4: 91–93, 1990)  相似文献   
77.
We analyzed association between p53 and/or Rb expression and clinicopathologic variables or Ag-NOR counts, and then ascertained whether p53 and/or Rb expression would be useful for estimating prognosis in 81 breast cancer patients. Positive p53 expression was significantly associated with post-menopausal status, axillary lymph node metastases and Ag-NOR counts, whereas low level Rb expression was significantly associated with tumor size. Moreover, the combination of p53 and Rb expression was significantly associated with Ag-NOR counts, although there was no significant association between p53 and Rb expression. In the univariate study, p53 expression as well as age and axillary lymph node metastases were significantly associated with survival, whereas Rb expression was not. In the multivariate study, p53 and/or Rb expression did not provide independent prognostic information, although axillary lymph node metastases was an important factor affecting survival. Our findings suggest that p53 and/or Rb expression may reflect tumor proliferation of breast cancer, but the prognostic value of such assays is limited.  相似文献   
78.
The relationship between nm23 expression, HPA staining, and other clinicopathological variables, i.e., axillary (AX) and internal mammary lymph node (IMN) metastases was assessed, and their prognostic values were analyzed. Positive HPA staining was found to be significantly correlated with tumor size, and with AX and IMN metastases, whereas negative nm23 expression was significantly correlated with AX and IMN metastases. A univariate study revealed that overall survival was correlated significantly with tumor size, AX and IMN metastases, and HPA staining, whereas nm23 expression did not appear to be a significant prognostic factor. In a multivariate study, only AX and IMN metastases were significant prognostic factors. When AX and IMN metastases were excluded from the Cox model, however, only HPA staining had independent prognostic value for survival. In this study, therefore, it may be concluded that HPA staining was more closely correlated with AX and IMN metastases, and with survival than nm23 expression.  相似文献   
79.
Although breast conserving treatment (BCT) has become the standard therapy for early breast cancer, breast removal is still recommended for patients with a tumor beneath the nipple or with Paget’s disease. We have employed transposition of a latissimus dorsi myocutaneous (LD-MC) flap after wide local excision of a tumor with the nipple-areola complex. A new nipple-areola complex was reconstructed on the LD-MC flap after breast irradiation. Utilizing reconstructive techniques, BCT will likely become the treatment of choice for more patients with early breast cancer.  相似文献   
80.
Radiation safety management condition in Japanese nuclear medicine facilities were investigated by the questionnaire method. The first questionnaire was asked in all Japanese 1,401 Nuclear Medicine facilities. Answers from 624 institutes (44.5%) were received and analyzed. The radiation-safety management in nuclear medicine institutes was considered to be very well performed everyday. Opinion for the present legal control of nuclear medicine institutes was that the regulation in Japan was too strict for the clinical use of radionuclides. The current regulation is based on the assumption that 1% of all radioactivity used in nuclear medicine institutes contaminates into the draining-water system. The second questionnaire detailing the contamination of radioactivity in the draining-water system was sent to 128 institutes, and 64 answers were received. Of them, 42 institutes were considered to be enough to evaluate the contamination of radioactivity in the draining-water system. There was no difference between 624 institutes answered to the first questionnaire and 42 institutes, where the radioactivity in the draining-water system was measured, in the distribution of the institute size, draining-water system equipment and the radioactivity measuring method, and these 42 institutes seemed to be representative of Japanese nuclear medicine institutes. Contamination rate of radioactivity into the draining system was calculated by the value of radioactivity in the collecting tank divided by the amount of radionuclides used daily in each institute. The institutes were divided into two categories on the basis of nuclear medicine practice pattern; type A: in-vivo use only and type B: both in-vivo and in-vitro use. The contamination rate in 27 type A institutes did not exceed 0.01%, whereas in 15 type B institutes the contamination rate distributed widely from undetectable to above 1%. These results indicated that the present regulation for the draining-water system, which assumed that 1% of all radioactivity used in nuclear medicine institutes contaminated into draining-water system, should be reconsidered in nuclear medicine facilities where radionuclides are used only in in-vivo studies.  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