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   2923265篇
  免费   226550篇
  国内免费   5528篇
耳鼻咽喉   39521篇
儿科学   96469篇
妇产科学   80860篇
基础医学   415695篇
口腔科学   86782篇
临床医学   264711篇
内科学   563976篇
皮肤病学   64358篇
神经病学   232313篇
特种医学   113452篇
外国民族医学   704篇
外科学   442601篇
综合类   70899篇
现状与发展   6篇
一般理论   1066篇
预防医学   225886篇
眼科学   69074篇
药学   218394篇
  9篇
中国医学   6409篇
肿瘤学   162158篇
  2018年   31141篇
  2017年   23919篇
  2016年   26380篇
  2015年   30191篇
  2014年   41896篇
  2013年   62727篇
  2012年   85820篇
  2011年   90512篇
  2010年   53532篇
  2009年   50335篇
  2008年   84957篇
  2007年   90173篇
  2006年   90993篇
  2005年   87821篇
  2004年   85591篇
  2003年   81689篇
  2002年   79320篇
  2001年   141920篇
  2000年   145971篇
  1999年   122303篇
  1998年   33453篇
  1997年   29698篇
  1996年   29621篇
  1995年   28568篇
  1994年   26645篇
  1993年   24764篇
  1992年   96942篇
  1991年   94149篇
  1990年   91265篇
  1989年   88043篇
  1988年   81166篇
  1987年   79580篇
  1986年   75597篇
  1985年   72593篇
  1984年   53954篇
  1983年   46341篇
  1982年   26807篇
  1981年   23972篇
  1979年   49955篇
  1978年   34479篇
  1977年   29337篇
  1976年   27555篇
  1975年   29116篇
  1974年   35507篇
  1973年   34085篇
  1972年   31497篇
  1971年   29536篇
  1970年   27345篇
  1969年   25617篇
  1968年   23590篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
Clinical versus ultrasonographic evaluation of scrotal disorders   总被引:1,自引:0,他引:1  
Clinical and ultrasonographic examinations of scrotal disorders were compared in 166 patients in order to determine their ability to distinguish between those diseases requiring surgery and those requiring clinical follow-up only. Ultrasound examinations were efficient in discriminating between normal and pathological findings. Extra-testicular lesions were readily differentiated from testicular ones. Although both clinical and ultrasonographic examinations had high sensitivity (90%) in detecting testicular cancer, the number of false positive findings was smaller after ultrasound examination. This gave a predictive value of a positive test of 53% after ultrasound examination but only 33% after clinical examination. Ultrasound examination may, therefore, reduce the number of surgical explorations in the scrotum and should be performed in patients with suspected testicular pathology based on history and palpatory findings.  相似文献   
992.
993.
Ten years experience with acute peritoneal dialysis in 39 preterm-, newborn and small infants shows advantage and low risk of surgically implanted single dacron cuffed silicone catheters compared to trocar catheters.  相似文献   
994.
995.
Neglected tears of the patellar tendon due to loss of active extension remain a difficult therapeutic endeavor. The goals in the approach to this diagnosis include restoration of both structural and functional integrity of the extensor mechanism. A procedure has been developed utilizing Z-shortening of the patellar tendon, Z-lengthening of the quadriceps tendon, and the semitendinosis gracilis as a biologic splint. This technique allows establishment of preoperative goals, including restoration of the muscle-tendon complex in its anatomic position, restoration of quadriceps function, preservation of vascularity of the reconstructed tendon, and splinting of the patellar tendon. This reconstruction allows early mobilization and rehabilitation.  相似文献   
996.
The effects of bulk versus particulate polymethylmethacrylate on bone   总被引:3,自引:0,他引:3  
Twenty-one mature New Zealand white female rabbits were allocated into three groups of seven rabbits. Group I received a bolus of doughy Simplex polymethylmethacrylate (PMMA) cement injected into the proximal tibia through a drill hole. Group II received a preformed, cooled, bulk PMMA pellet. Group III had particulate PMMA powder implanted. The operated, but nonimplanted, left tibiae served as controls. Animals were killed after four months. Histologically, both Group I and Group II demonstrated a thin, fibrous tissue membrane at the implant interface. Particulate PMMA (Group III) stimulated a much thicker, florid, foreign body reaction composed of histiocytes and giant cells. The foreign body response to particulate acrylic cement was similar to that seen in failed cemented joint replacement arthroplasty in humans.  相似文献   
997.
We report spectrophotometric methods for quantifying sodium and potassium in serum and plasma without sample pretreatment or solvent-extraction steps. The methods are based on novel chromogenic ionophores characterized by molecular structures highly preorganized for binding, which result in exceptionally high sensitivity and selectivity (negligible responses to sodium at 80 to 200 mmol/L in the potassium assay and to potassium at 0 to 10 mmol/L in the sodium assay). The within-run imprecisions are comparable with those for ion-selective electrodes (for K, 1.0% at 4.5 mmol/L; for Na, 1.1% at 136 mmol/L); the analytical range is 2-10 mmol/L for potassium, 80-170 mmol/L for sodium. The results for greater than 100 patients' samples correlated well with results obtained with ion-selective electrodes (r = 0.99 for K, 0.97 for Na). The ready-to-use aqueous reagents will be available under the trade name of ChromoLyte for use with Technicon's RA family of clinical analyzers.  相似文献   
998.
Differentiation of cardiac murmurs by dynamic auscultation   总被引:1,自引:0,他引:1  
The techniques described in this monograph will aid in the accurate identification of the origin of a cardiac murmur or abnormal heart sound. They do not necessarily reveal the presence or severity of cardiac disease. No maneuver is 100% accurate in elucidation of cardiac abnormalities, and a given maneuver's effectiveness varies in its application. The systematic application of a combination of maneuvers improves the accuracy of diagnosis. Auscultatory findings must be interpreted with consideration of the total clinical examination including history, other physical findings, ECG, chest x-ray, and possibly an echocardiogram. Thus, the careful physiological approach to the physical examination represents a powerful noninvasive tool that can be used in combination with other information to accurately diagnose cardiac disease in many patients and efficiently direct further evaluation when necessary.  相似文献   
999.
The present study demonstrates that alcohol-induced memory impairment can be attenuated by pretreatment with an oral tryptophan supplementation. These results provide support for the role of a brain serotonin deficit in this impairment and highlight the impact a dietary manipulation can have on a complex behavioral process.  相似文献   
1000.
A murine monoclonal antibody PASE/4LJ to prostatic acid phosphatase (PAP) was used to immunostain a wide variety of sections of benign and malignant tissues (654 blocks). Non-neoplastic adult and fetal prostatic glands, primary and metastatic prostatic carcinomas, and scattered cells in prostatic and penile urethra were positive. Rat, dog and rabbit prostates were negative. Nine of 400 tumours of non-prostatic origin showed some positivity: 6/36 carcinoids, 1/9 islet cell tumours, 1/55 ovarian adenocarcinomas (serous) and one carcinosarcoma of the lung (epithelial portion). Positive staining was seen in islet cells in 4/5 specimens of normal pancreas, and in 4/9 blocks of normal pancreas surrounding a pancreatic tumour. Loops of Henle, maculae densae, and distal tubules in 10/10 fetal and 2/9 adult kidneys were also positive, with proximal tubules and collecting ducts negative. All other 159 blocks of non-neoplastic adult and fetal tissues were negative. The antibody was also affinity purified from ascitic fluid, and shown not to inhibit the enzyme activity of prostatic acid phosphatase.  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