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   13844篇
  免费   989篇
  国内免费   40篇
耳鼻咽喉   83篇
儿科学   252篇
妇产科学   246篇
基础医学   1941篇
口腔科学   432篇
临床医学   1764篇
内科学   2714篇
皮肤病学   281篇
神经病学   1129篇
特种医学   600篇
外科学   2051篇
综合类   121篇
一般理论   2篇
预防医学   1209篇
眼科学   246篇
药学   844篇
中国医学   34篇
肿瘤学   924篇
  2023年   84篇
  2022年   94篇
  2021年   224篇
  2020年   160篇
  2019年   219篇
  2018年   290篇
  2017年   263篇
  2016年   250篇
  2015年   236篇
  2014年   359篇
  2013年   530篇
  2012年   707篇
  2011年   761篇
  2010年   392篇
  2009年   355篇
  2008年   615篇
  2007年   632篇
  2006年   613篇
  2005年   524篇
  2004年   541篇
  2003年   462篇
  2002年   430篇
  2001年   364篇
  2000年   449篇
  1999年   381篇
  1998年   185篇
  1997年   144篇
  1996年   133篇
  1995年   150篇
  1994年   128篇
  1993年   106篇
  1992年   322篇
  1991年   329篇
  1990年   325篇
  1989年   273篇
  1988年   255篇
  1987年   287篇
  1986年   271篇
  1985年   208篇
  1984年   211篇
  1983年   187篇
  1982年   102篇
  1981年   85篇
  1979年   123篇
  1978年   92篇
  1977年   83篇
  1975年   76篇
  1974年   75篇
  1973年   81篇
  1970年   72篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
52.
In a pilot study of 6 patients with subarachnoid hemorrhage caused by a ruptured intracranial (grade IV (Hunt and Hess) aneurysm the hemodynamics and plasma-nimodipine concentrations have been observed during a 3-week period of treatment. We found that 3 patients developed reversible hypotension during the nimodipine treatment and that the hypotension tendency could be related to the plasmanimodipine level and not to a more or less severe sensitivity to nimodipine.

Repeated measurements of blood pressure, plasma-nimodipine and regional cerebral blood flow (rCBF) are necessary for the purpose of obtaining the optimum treatment and for evaluating the effect of treatment.  相似文献   

53.
Sucralfate, a basic aluminum salt of sucrose, was the first successful drug with a major cytoprotective mechanism of action. It binds bile acids and pepsin and adheres to both ulcerated and nonulcerated mucosa. Sucralfate stimulates the synthesis and release of gastric mucosal prostaglandins as well as bicarbonate and the epidermal growth factor which stimulates healing. Sucralfate is the safest drug available today in the treatment of dyspeptic symptoms and compared to ranitidine and cimetidine it has the following characteristics. (2) The short-term healing of duodenal ulcers is the same for sucralfate, cimetidine and ranitidine. (3) Sucralfate-treated patients have a lower recurrence rate of duodenal ulceration after healing when compared with cimetidine and the recurrence rate is not connected with the presence or absence of Campylobacter pylori.  相似文献   
54.
The purpose of this study was to identify factors which will predict the risk of severe postoperative complications in individual patients in a neurosurgical unit. Eleven risk factors were investigated in 363 neurosurgical patients, of whom 40 (11%) developed postoperative complications requiring mechanical ventilation for more than 24 h in an intensive care unit, 16 were found to be severely disabled or in a vegetative state at follow-up 1 month after admission, and 28 patients died. By applying stepwise, logistic regression analysis to the patient's data, we were able to select two significant risk variables, i.e. the Glasgow Coma Scale (GCS) 8 or less preoperatively and emergency anaesthesia. The presence of GCS 8 or less on the consciousness scale was associated with postoperative complications in approximately 40% of the cases. Emergency patients with severe neurological damage had the greatest risk of postoperative complications (93%). Fatal outcome for patients with postoperative complications was seen in 40% of the cases.  相似文献   
55.
The distribution of sympathetic preganglionic neurons (SPN) projecting to the adrenal medulla and the aorticorenal ganglion in the rabbit was studied using a dual retrograde transport technique. The B subunit of cholera toxin (CTB) was injected into the left adrenal medulla and wheatgerm agglutinin-apo-horseradish peroxidase-7 nm gold (WGA-apo-HRP-gold) was injected into the left aorticorenal ganglion. Retrogradely transported CTB was detected by immunohistochemistry, while gold particles were detected by silver intensification. SPN projecting to the adrenal medulla were observed in segments T2-L2 of the spinal cord in 5 rabbits, with the majority of cells within segments T6-T11 (79%). SPN projecting to the aorticorenal ganglion were seen in segments T2-L1 of the spinal cord in 5 rabbits, with the greatest number of the cells within T6-T11 (81%). Only a small number of doubly labelled cells (1%) were found in two rabbits. The results suggest that despite their similar segmental distribution SPN projecting to the adrenal medulla or the aorticorenal ganglion belong to separate populations and few, if any, individual SPN have axonal projections to both locations.  相似文献   
56.
All first-time admissions from 1970 to 1986 with obsessive-compulsive neurosis (OCD) (ICD-8 diagnosis number 300.39) or obsessive-compulsive personality disorder (OCPD) (ICD-8 diagnosis number 301.49) were analyzed based on an extract from the nationwide Psychiatric Case Register in Denmark. All patients with secondary diagnoses other than neurotic disorders or personality disorders (including “neuroses characterogenes”) were excluded from the study. A total of 284 patients were first-time admitted with a main diagnosis of OCD during the period. The sex ratio was 0.67 (males/females). A total of 126 were first-time admitted with a diagnosis of OCPD, with a sex ratio of 1.18 (males/females). Seventy-seven percent of the readmitted patients with a first-time diagnosis of OCD kept a diagnosis within the “emotional spectrum” at the last admission. About half kept OCD as a main diagnosis, whereas only 15% shifted to a severe psychiatric diagnosis such as schizophrenia or manic-depressive psychosis. Of the readmitted patients with OCPD. 13% later developed a diagnosis of manic-depressive psychosis.  相似文献   
57.
A method is suggested and described which allows to introduce areas of different sizes, shapes, sites, and doses into a photon irradiation field. The bases for calculation and manufacturing of such irregular field stops containing integrated dose modification blocks are, according to precision requirements and data acquisition possibilities, either information provided by computed tomography or conventional planning radiographs. The following standard parameters are required as input data: sizes, shapes, and positions of the partial fields within the total irradiation field, depth of the reference plane, absorption coefficient of the modification material used, proportions of the planned dose modification, radiation quality, and other radiation field parameters. For the calculation of the dose distributions within the generally irregularly shaped irradiation volumes, an iterative algorithm has been formulated following the differential sector addition method and an equivalent TAR scheme. The quality of such a modifier can be checked by standard dosimetric methods. Deviations from the planned dose modification can be defined as sigma = +/- 5% for the radiation qualities employed (60Co gamma radiation and 15 MeV bremsstrahlung of a linear accelerator).  相似文献   
58.
We investigated the effects of polymerization heat and toxicity of polymethyimetacrylate bone cement in the canine tibial diaphysis. Heat was studied by filling the tibias with either bone cement or bone wax contained in a monomer tight membrane pouch. Toxicity was studied by filling both tibias with cement, with the control side contained in the membrane pouch. Bone blood perfusion was measured by microsphere technic, and bone remodeling by 99mTc-methylene diphosphonate uptake and by histologic technique. In bone exposed to the combination of polymerization heat and monomer, both perfusion and remodeling were impaired. We did not find any effects of polymerization heat alone.

We conclude that hot toxic chemicals from bone cement during polymerization may inhibit bone blood perfusion and remodeling, whereas heat alone seems to be of minor importance for the regenerative processes in cemented diaphyseal bone.  相似文献   
59.
14 children suffering from a fracture of the talar neck or body were examined after 21 (7-34) years. The talar neck was fractured in 10 children and the talar body in 4. 3 fractures were displaced and primarily treated with reduction and immobilization. Nondisplaced fractures were treated conservatively. All fractures healed. All patients with displaced fractures had exercise-induced pain at follow-up. Of 11 patients with nondisplaced fractures only 1 had minor complaints.

CT and conventional radiographs showed arthrosis in the talocrural joint and normal subtalar joints in those with displaced fractures. The radio- graphic findings were normal after nondisplaced fractures.  相似文献   
60.
Transgenic mice overexpressing the phosphoenolpyruvate carboxykinase/bovine growth hormone (PEPCK/ bGH) hybrid gene and normal (nontransgenic) littermate controls (10 males + 10 females/group) were given access to tapwater and an ascending series of concentrations of ethanol (1.0–22.0%), then a similar ascending series of concentrations of nicotine (1.0–40.0 μg/ml), in a two-bottle choice test. Male transgenic mice consumed more and exhibited greater preferences for ethanol and nicotine than control males; transgenic females consumed less and showed lower preferences for ethanol, but not nicotine, than control females. These results suggest that chronic exposure to high levels of bGH may modulate the rewarding effects of ethanol and nicotine in mice in a gender-specific fashion.  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