全文获取类型
收费全文 | 7073篇 |
免费 | 519篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 80篇 |
儿科学 | 339篇 |
妇产科学 | 127篇 |
基础医学 | 567篇 |
口腔科学 | 782篇 |
临床医学 | 513篇 |
内科学 | 1633篇 |
皮肤病学 | 111篇 |
神经病学 | 441篇 |
特种医学 | 239篇 |
外国民族医学 | 1篇 |
外科学 | 1132篇 |
综合类 | 110篇 |
一般理论 | 2篇 |
预防医学 | 266篇 |
眼科学 | 226篇 |
药学 | 404篇 |
中国医学 | 20篇 |
肿瘤学 | 630篇 |
出版年
2024年 | 9篇 |
2023年 | 125篇 |
2022年 | 157篇 |
2021年 | 237篇 |
2020年 | 147篇 |
2019年 | 214篇 |
2018年 | 299篇 |
2017年 | 200篇 |
2016年 | 265篇 |
2015年 | 243篇 |
2014年 | 384篇 |
2013年 | 405篇 |
2012年 | 602篇 |
2011年 | 614篇 |
2010年 | 354篇 |
2009年 | 319篇 |
2008年 | 465篇 |
2007年 | 465篇 |
2006年 | 368篇 |
2005年 | 342篇 |
2004年 | 314篇 |
2003年 | 236篇 |
2002年 | 201篇 |
2001年 | 61篇 |
2000年 | 62篇 |
1999年 | 66篇 |
1998年 | 46篇 |
1997年 | 39篇 |
1996年 | 50篇 |
1995年 | 36篇 |
1994年 | 28篇 |
1993年 | 35篇 |
1992年 | 26篇 |
1991年 | 42篇 |
1990年 | 25篇 |
1989年 | 28篇 |
1988年 | 11篇 |
1987年 | 18篇 |
1986年 | 14篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 11篇 |
1981年 | 11篇 |
1980年 | 4篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有7623条查询结果,搜索用时 15 毫秒
1.
Danut Vai
iukynien Aras Kantautas Simona Tu
kut Fallon Manhanga Eugenijus Janavi
ius Ernestas Ivanauskas
ymantas Rudionis Aloyzas Gaudutis 《Materials》2021,14(10)
Concrete plants accumulate large amounts of concrete wash water. This water, which pH is highly alkaline, has a negative impact on the environment. Its reuse in fresh concrete slightly reduces its mechanical properties. The combination of concrete wash water and zeolitic by-product led to an increase of 4.6% in the compressive strength at 7 days hydration and up to 30% at 28 days hydration. The same combination led to the denser microstructure compared to the samples made with concrete wash water. This could be explained by the pozzolanic reaction of the zeolitic by-product. The complex chemical reactions of cement, zeolitic by-product, and fines presented in the concrete wash water occurred. Therefore, it was suggested the reusing method of concrete wash water together with zeolitic by-product in the fresh concrete mixtures by substituting some amount of tap water with concrete wash water. In this way, the consumption of tap water is possible to reduce in cement systems. 相似文献
2.
3.
Ajay Punpale C S Pramesh Nirmala Jambhekar Rajesh C Mistry 《Annals of thoracic and cardiovascular surgery》2006,12(6):425-427
Liposarcomas are extremely rare in the mediastinum. They may achieve considerable size before causing any symptoms. Mediastinal liposarcomas may invade surrounding structures like the pericardium or the superior vena cava. Complete surgical excision is the optimal treatment in resectable cases. Excision of adjacent structures like the pericardium may be needed if the tumor infiltrates them. We report on a case of a giant liposarcoma of the mediastinum involving both hemithoraces and extending into the neck, which was successfully managed by complete surgical excision. 相似文献
4.
Since the first transurethral resection of the prostate (TURP) was performed by Guyon at the Necker Hospital in Paris in 1901,
this treatment modality has replaced open prostatectomy as the procedure of choice for more than 95% of patients. TURP has
been used in surgical treatment of benign prostatic hyperplasia (BPH) and remains the gold standard treatment. Transurethral
vapor resection of the prostate (TUVRP) and holmium laser enucleation of the prostate (HoLEP) are new treatment modalities
for the treatment of BPH. Each procedure has its own advantages and disadvantages. Availability of instruments, surgical expertise,
and specific indications for a particular procedure are of utmost importance for successful outcome, with minimal morbidity.
TURP can be either monopolar or bipolar, using thin or thick loop. Bipolar TURP is associated with less bleeding and less
chances of dilutional hyponatremia. TUVRP, using a thick wedge loop, causes vaporization and resection of the prostate, and
is associated with less bleeding and short operative time. HoLEP is another effective alternative for the surgical treatment
of BPH. The holmium laser possesses the ideal combination of cutting and coagulation; however, it has a learning curve. 相似文献
6.
A 50 year old man with a two month history of upper abdominal pain and a one month history of anorexia and weight loss, presented
with icterus and evidence of peritonitis. Laparotomy revealed biliary peritonitis which had been caused by a rupture of the
fundus of the gallbladder. The common bile duct was dilated and there was a large growth in the head of the pancreas with
multiple hepatic metastases. A cholecysto-jejunostomy and gastrojejunostomy were done and the patient had an uneventful recovery. 相似文献
7.
A forty year old female patient developed paraesthesia of the right side of her lower lip following the placement of an extensive pin-retained amalgam restoration in her lower right second premolar tooth. Radiographs indicated that the mental foramen was close to the apex of this tooth and it was assumed that postoperative pulpitis and periapical inflammation had caused the paraesthesia through the effects of pressure on the mental nerve. The paraesthesia resolved following endodontic treatment of the lower second premolar tooth and the patient has had no further signs or symtoms. 相似文献
8.
J Douglas Bremner Meena Vythilingam Eric Vermetten George Anderson John W Newcomer Dennis S Charney 《Neuropsychopharmacology》2004,55(8):811-815
BACKGROUND: Major depression has been associated with hypercortisolemia in a subset of patients with depression. Administration of exogenous cortisol and other glucocorticoids to healthy human subjects has been observed to result in a transient impairment in verbal declarative memory function. The purpose of this study was to assess the effects of the glucocorticoid, dexamethasone, on verbal declarative memory function in patients with untreated unipolar major depressive disorder (MDD). METHODS: Fifty two men and women with (n = 28) and without (n = 24) MDD received placebo or dexamethasone (1 mg and 2 mg on 2 successive days) in a double-blind, randomized fashion. Declarative memory was assessed with paragraph recall at baseline (day 1) and day 3. RESULTS: There was a significant interaction between diagnosis and drug (dexamethasone vs. placebo) on paragraph recall. In the healthy subjects, memory improved from baseline to day 3 with placebo and was unchanged with dexamethasone, whereas in MDD patients memory function showed a pattern of decreasing with placebo and improving with dexamethasone from baseline to day 3. CONCLUSIONS: These findings are consistent with an altered sensitivity of declarative memory function in MDD to regulation by glucocorticoids. Possible explanations of the findings include alterations in glucocorticoid receptors in the hippocampus or other brain regions mediating declarative memory, or differential sensitivity to dexamethasone-induced reductions in cortisol, in patients with MDD. 相似文献
9.
Joseph G Rajendran Darrell R Fisher Ajay K Gopal Lawrence D Durack Oliver W Press Janet F Eary 《Journal of nuclear medicine》2004,45(6):1059-1064
Radioimmunotherapy (RIT) using (131)I-tositumomab has been used successfully to treat relapsed or refractory B-cell non-Hodgkin's lymphoma (NHL). Our approach to treatment planning has been to determine limits on radiation absorbed dose to critical nonhematopoietic organs. This study demonstrates the feasibility of using CT to adjust for actual organ volumes in calculating organ-specific absorbed dose estimates. METHODS: Records of 84 patients who underwent biodistribution studies after a trace-labeled infusion of (131)I-tositumomab for RIT (January 1990 and April 2003) were reviewed. Serial planar gamma-camera images and whole-body NaI probe counts were obtained to estimate (131)I-antibody source-organ residence times as recommended by the MIRD Committee. The source-organ residence times for standard man or woman were adjusted by the ratio of the MIRD phantom organ mass to the CT-derived organ mass. RESULTS: The mean radiation absorbed doses (in mGy/MBq) for our data using the MIRD model were lungs = 1.67; liver = 1.03; kidneys = 1.08; spleen = 2.67; and whole body = 0.3; and for CT volume-adjusted organ volumes (in mGy/MBq) were lungs = 1.30; liver = 0.92; kidneys = 0.76; spleen = 1.40; and whole body = 0.22. We determined the following correlation coefficients between the 2 methods for the various organs: lungs, 0.49 (P = 0.0001); liver, 0.64 (P = 0.004); kidneys, 0.45 (P = 0.0004); spleen, 0.22 (P = 0.0001); and whole body, 0.78 (P = 0.0001), for the residence times. For therapy, patients received mean (131)I administered activities of 19.2 GBq (520 mCi) after adjustment for CT-derived organ mass compared with 16.0 GBq (433 mCi) that would otherwise have been given had therapy been based only using standard MIRD organ volumes-a statistically significant difference (P = 0.0001). CONCLUSION: We observed large variations in organ masses among our patients. Our treatments were planned to deliver the maximally tolerated radiation dose to the dose-limiting normal organ. This work provides a simplified method for calculating patient-specific radiation doses by adjusting for the actual organ mass and shows the value of this approach in treatment planning for RIT. 相似文献
10.
Joseph G Rajendran Ajay K Gopal Darrel R Fisher Larry D Durack Ted A Gooley Oliver W Press 《Journal of nuclear medicine》2008,49(5):837-844
Myeloablative radioimmunotherapy using (131)I-tositumomab (anti-CD20) monoclonal antibodies is an effective therapy for B-cell non-Hodgkin's lymphoma. The amount of radioactivity for radioimmunotherapy may be determined by several methods, including those based on whole-body retention and on dose to a limiting normal organ. The goal of each approach is to deliver maximal myeloablative amounts of radioactivity within the tolerance of critical normal organs. METHODS: Records of 100 consecutive patients who underwent biodistribution and dosimetry evaluation after tracer infusion of (131)I-tositumomab before radioimmunotherapy were reviewed. We assessed organ and tissue activities over time by serial gamma-camera imaging to calculate radiation-absorbed doses. Organ volumes were determined from CT scans for organ-specific dosimetry. These dose estimates helped us to determine therapy on the basis of projected dose to the critical normal organ receiving a maximum tolerable radiation dose. We compared organ-specific dosimetry for treatment planning with the whole-body dose-assessment method by retrospectively analyzing the differences in projected organ-absorbed doses and their ratios. RESULTS: Mean organ doses per unit of administered activity (mGy/MBq) estimated by both methods were 0.33 for liver and 0.33 for lungs by the whole-body method and 1.52 for liver and 1.74 for lungs by the organ-specific method (P=0.0001). The median differences between methods were 0.92 mGy/MBq (range, 0.36-2.2 mGy/MBq) for lungs, 0.82 mGy/MBq (range, 0.28-1.67 mGy/MBq) for liver, and -0.01 mGy/MBq (range, -0.18-0.16 mGy/MBq) for whole body. The median ratios of the treatment activities based on limiting normal-organ dose were 5.12 (range, 2.33-10.01) for lungs, 4.14 (range, 2.16-6.67) for liver, and 0.94 (range, 0.79-1.22) for whole body. We found substantial differences between the dose estimated by the 2 methods for liver and lungs (P=0.0001). CONCLUSION: Dosimetry based on whole-body retention will underestimate the organ doses, and a preferable approach is to evaluate organ-specific doses by accounting for actual radionuclide biodistribution. Myeloablative treatments based on the latter approach allow administration of the maximum amount of radioactivity while minimizing toxicity. 相似文献